Patellar tendon versus hamstring tendon autografts for anterior cruciate ligament reconstruction: a randomized controlled trial using similar femoral and tibial fixation methods

Validating the capture rate of revisions by the New Zealand ACL Registry: An analysis of all-cause reoperation following primary ACL reconstruction

PURPOSE

To validate the New Zealand Anterior Cruciate Ligament (ACL) Registry's capture rate of revisions by cross-referencing Registry data with reoperations data recorded by the Accident Compensation Corporation (ACC) and identify risk factors for all-cause reoperation.

METHODS

Primary ACL reconstructions performed between April 2014 and September 2019 were individually matched on a record-by-record basis between the two databases. The ACC database was used to identify patients who underwent a reoperation with manual review of operation notes to identify whether a revision or other procedure was performed. This was combined with the number of revisions separately recorded in the New Zealand ACL Registry, which was used as the denominator value to calculate the Registry's capture rate of revisions. Patient and surgical data recorded in the Registry were analysed to identify independent predictors for all-cause reoperation.

RESULTS

A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and the ACC databases. The reoperation rate was 8.9% (n = 715) at a mean follow-up of 2.5 years. Meniscal-related procedures were the most common reoperation (n = 299, 3.7%), followed by revision ACL reconstruction (n = 219, 2.7%), arthrofibrosis (n = 185, 2.3%), cartilage (n = 56, 0.7%) and implants (n = 32, 0.4%). The New Zealand ACL Registry captured 96% of revisions. Younger age (hazard ratio [HR] > 1.4, p < 0.001), earlier surgery (HR > 1.3, p = 0.05), concurrent meniscal repair (medial meniscus HR = 1.9, p < 0.001 and lateral meniscus HR = 1.3, p = 0.022) and hamstring tendon autografts (HR = 1.4, p = 0.001) were associated with a higher risk of reoperation.

CONCLUSION

The New Zealand ACL Registry captured 96% of revisions. Risk factors for all-cause reoperation included younger age, earlier surgery, meniscal repair and hamstring tendon autografts.

LEVEL OF EVIDENCE

Level III.

Following Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Autograft, the Incidence of Anterior Knee Pain Ranges From 5.4% to 48.4% and the Incidence of Kneeling Pain Ranges From 4.0% to 75.6%: A Systematic Review of Level I Studies

Purpose

To (1) perform a systematic review of level I randomized controlled trials (RCTs) detailing the incidence of anterior knee pain and kneeling pain following anterior cruciate ligament reconstruction (ACLR) with bone-patellar tendon-bone (BPTB) autograft and (2) investigate the effect of bone grafting the patellar harvest site on anterior knee and kneeling pain.

Methods

A systematic review of level I studies from 1980 to 2023 was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome evaluated was the presence of donor site morbidity in the form of anterior knee pain or kneeling pain. A secondary subanalysis was performed to assess for differences in the incidence of postoperative pain between patient groups undergoing ACLR with BPTB receiving harvest site bone grafting and those in whom the defect was left untreated.

Results

Following full-text review, 15 studies reporting on a total of 696 patients met final inclusion criteria. Patients were followed for an average of 4.78 years (range, 2.0-15.3), and the mean age ranged from 21.7 to 38 years old. The incidence of anterior knee pain, calculated from 354 patients across 10 studies, ranged from 5.4% to 48.4%. The incidence of postoperative pain with kneeling was determined to range from 4.0% to 75.6% in 490 patients from 9 studies. Patients treated with bone grafting of the BPTB harvest site had no significant difference in incidence of any knee pain compared with those who were not grafted, with incidences of 43.3% and 40.2%, respectively.

Conclusions

Based on the current level I RCT data, the incidences of anterior knee pain and kneeling pain following ACLR with BPTB autograft range from 5.4% to 48.4% and 4.0% to 75.6%, respectively.

Level of Evidence

Level I, systematic review of RCTs.

The impact of bone graft type used to fill bone defects in patients undergoing ACL reconstruction with bone-patellar tendon-bone (BPTB) autograft on kneeling, anterior knee pain and knee functional outcomes

PURPOSE

Multiple different materials are used for filling bone defects following bone-patellar tendon-bone (BPTB) graft ACL reconstruction surgery. The theoretical objective being to minimize kneeling pain, improve clinical outcomes and reduce anterior knee pain following surgery. The impact of these materials is assessed in this study.

METHODS

A prospective monocentric cohort study was conducted from January 2018 to March 2020. There were 128 skeletally mature athletic patients who underwent ACL reconstruction using the same arthroscopic-assisted BPTB technique, with a minimum follow-up of two years identified in our database. After obtaining approval from the local ethics committee, 102 patients were included in the study. Patients were divided into three groups based on type of bone substitute. The Bioactive glass 45S5 ceramic Glassbone™ (GB), collagen and hydroxyapatite bone void filler in sponge form Collapat® II (CP), and treated human bone graft Osteopure®(OP) bone substitutes were used according to availability. Clinical evaluation of patients at follow-up was performed using the WebSurvey software. A questionnaire completed in the 2nd post-operative year included three items: The ability to kneel, the presence of donor site pain, and the palpation of a defect. Another assessment tool included the IKDC subjective score and Lysholm score. These two tools were completed by patients preoperatively, and postoperatively on three occasions (6 months, 1 year, and 2 years).

RESULTS

A total of 102 patients were included in this study. In terms of Kneeling pain, the percentage of GB and CP patients' who kneel with ease were much higher than that of OP patients (77.78%, 76.5% vs 65.6%, respectively). All three groups experienced an important increase in IKDC and Lysholm scores. There was no difference in anterior knee pain between the groups.

CONCLUSION

The use of Glassbone® and Collapat II® bone substitutes reduced the incidence of kneeling pain compared to Osteopure®. There was no influence of the bone substitute type on the functional outcome of the knee or on the anterior knee pain at two years of follow.

Timing of Outcomes and Expectations After Knee Surgery in the US Military: A Systematic Review

CONTEXT

Knee injury and subsequent surgery are widespread in the military setting. Associations between knee surgery and expected outcomes over time have not been consolidated and characterized systematically by procedure type across the body of literature, and the temporal expectations of these outcomes remain unclear.

OBJECTIVE

To summarize common postoperative follow-up times and associated outcomes that determine clinical or surgical failure in US service members after elective knee surgery.

DATA SOURCES

A systematic search was conducted with 3 bibliographic databases of published research reports from 2010 through 2021.

STUDY SELECTION

Studies in US military service members undergoing elective knee surgery, with a minimum of 1-year follow-up, and reporting on a functional/occupational outcome were included. Three reviewers screened all abstracts and full-text articles to determine eligibility.

STUDY DESIGN

Systematic review of longitudinal cohort studies.

LEVEL OF EVIDENCE

Level 2a.

DATA EXTRACTION

Extracted data included military demographics, surgical procedure variables, surveillance period, and outcome measures. The Newcastle-Ottawa Scale and the Grading of Recommendations Assessment, Development, and Evaluation approach were used to determine study quality and risk of bias.

RESULTS

A total of 22 studies (mean follow-up time of 40.7 months) met the inclusion criteria. For cruciate ligament repair, approximately one-third of patients required a second surgery or were medically separated from military service by 2 years from surgery; 100% were reinjured by 4 years, and 85% sustained a new injury within 5 years of surgery. For meniscal repair, nearly one-third of patients were medically separated, and half were placed on activity restrictions within 3 years of surgery. For articular cartilage repair, within 5 years, 39% of patients required a second surgery, 30% were placed on activity restrictions, and 36% were medically separated. For patellar repair, 37% of patients were medically separated and over half were placed on activity restrictions within 5 years.

CONCLUSION

Common knee surgeries can have long-term implications for military careers that may not become apparent with shorter follow-up periods (<2 years). When longer surveillance periods are used (eg, up to 5 years), additional surgical procedures are more common and the likelihood of being injured or medically separated from military service is higher.

Bone-patellar tendon-bone versus two- and four-strand hamstring tendon autografts for ACL reconstruction in young adults: a Bayesian network meta-analysis

Bone-patellar tendon-bone (BPTB), two- and four-strand hamstring tendon (4SHT and 2SHT, respectively) are the most common autografts used for anterior cruciate ligament (ACL) reconstruction. The present study compared BPTB, 2SHT, and 4SHT for ACL reconstruction in terms of joint laxity, patient reported outcome measures (PROMs), rate of failure and anterior knee pain (AKP). The time to return to sport and the peak torque between the autografts were also compared. Finally, prognostic factors leading to worse outcomes were also investigated. It was hypothesized that all grafts yield similar proprieties in terms of joint laxity, patient reported outcome measures (PROMs) and rate of failure, but that the BPTB autograft causes a greater rate of anterior knee pain (AKP). The literature search was conducted. All clinical trials comparing BTPB and/or 2SHT, and/or 4SHT were accessed. Grafts other than BTPB and/or 4SHT and/or 2SHT were not considered. Articles reporting outcomes of allografts or synthetic grafts were not eligible, nor were those concerning revision settings. Articles reporting ACL reconstruction in patients with multi-ligament damage were also not eligible. Data from 95,575 procedures were retrieved. The median length of follow-up was 36 months. The median age of the patients was 27.5 years. With regard to joint laxity, similarity was found in terms of Lachman and Pivot shift tests between all three autografts. The BPTB demonstrated the greatest stability in terms of instrumental laxity. BPTB demonstrated the greatest PROMs. BPTB demonstrated the greatest rate of AKP, while AKP in 2SHT and 4SHT was similar. Concerning failure, statistically significant inconsistency was found (P = 0.008). The 4SHT demonstrated the quickest return to sport, followed by BPTB, and 2SHT. There was evidence of a negative association between the time span between injury to surgery, Lysholm score (P = 0.04), and Tegner scale (P = 0.04). Furthermore, there was evidence of a weak positive association between the time span between injury to surgery and return to sport (P = 0.01). BPTB may result in lower joint laxity, greater PROMs, and greater peak flexion torque compared to 2SHT and 4SHT autografts. On the other hand, BPTB reported the lowest peak extension torque and the greatest rate of AKP. Finally, a longer time span between injury and surgery negatively influences outcome.

The reverse fragility index: RCTs reporting non-significant differences in failure rates between hamstring and bone-patellar tendon-bone autografts have fragile results

PURPOSE

The reverse fragility index (RFI) is a novel metric to appraise the results of studies reporting statistically non-significant results. The purpose of this study was to determine the statistical robustness of randomized controlled trials (RCTs) reporting non-significant differences in anterior cruciate ligament reconstruction (ACLR) graft failure rates, defined as re-rupture/revision ACLR rate, between hamstring tendon (HT) and bone-patellar tendon-bone (BTB) autografts by calculating RFIs.

METHODS

A systematic review was performed to identify RCTs that compared HT to BTB grafts for ACLR through January 2022. Studies reporting non-significant differences in graft re-rupture and revision ACLR rate (n.s.) were included. The RFI, defined as the fewest number of event reversals needed to change the non-significant graft re-rupture/revision outcome to statistically significant (P < 0.05), was recorded for each study. In addition, the number of studies in which the loss to follow-up exceeded the RFI was recorded.

RESULTS

Among the 16 included RCTs, the median (interquartile range [IQR]) sample size was 71 (64-114), and the median (IQR) total number of graft re-rupture/revision ACLR events was 4 (4-6). The median (IQR) graft re-rupture/revision ACLR rate was 4.3% (3.0-6.4) overall, 4.1% (2.6-6.7) in the BTB group, and 5.4% (3.0-6.3) in the HT group. The median (IQR) RFI was 3 (3-4), signifying that a reversal of the outcome in 3 patients in one arm was needed to flip the studies' result from non-significant to statistically significant (P < 0.05). The median (IQR) number of participants lost to follow-up was 11 (3-13), and 13 (81.3%) of the included studies had a loss to follow-up greater than the studies' RFI.

CONCLUSION

The results of RCTs reporting statistically non-significant re-rupture/revision ACLR rates between HT and BTB autografts would become significant if the outcome were reversed in a small number of patients-a number that was less than the loss to follow-up in the majority of studies. Thus, the neutrality of these studies is fragile, and a true statistically significant difference in re-rupture/revision rates may have been undetected.

LEVEL OF EVIDENCE

Level I.

Canine ACL reconstruction with an injectable hydroxyapatite/collagen paste for accelerated healing of tendon-bone interface

Healing of an anterior cruciate ligament (ACL) autologous graft in a bone tunnel occurs through the formation of fibrovascular scar tissue, which is structurally and compositionally inferior to normal fibrocartilaginous insertion and thus may increase the reconstruction failure and the rate of failure recurrence. In this study, an injectable hydroxyapatite/type I collagen (HAp/Col Ⅰ) paste was developed to construct a suitable local microenvironment to accelerate the healing of bone-tendon interface. Physicochemical characterization demonstrated that the HAp/Col Ⅰ paste was injectable, uniform and stable. The in vitro cell culture illustrated that the paste could promote MC3T3-E1 cells proliferation and osteogenic expression. The results of a canine ACL reconstruction study showed that the reconstructive ACL had similar texture and color as the native ACL. The average width of the tunnel, total bone volume, bone volume/tissue volume and trabecular number acquired from micro-CT analysis suggested that the healing of tendon-bone interface in experimental group was better than that in control group. The biomechanical test showed the maximal loads in experimental group achieved approximately half of native ACL's maximal load at 24 weeks. According to histological examination, Sharpey fibers could be observed as early as 12 weeks postoperatively while a typical four-layer transitional structure of insertion site was regenerated at 48 weeks in the experimental group. The injectable HAp/Col Ⅰ paste provided a biomimetic scaffold and microenvironment for early cell attachment and proliferation, further osteogenic expression and extracellular matrix deposition, and in vivo structural and functional regeneration of the tendon-bone interface.

•

A stable and injectable HAp/Col I paste was designed, optimized and characterized.

•

The paste was applied in ACL reconstruction with an established standard operation procedure.

•

Provided the safety and efficacy evidence for ACL reconstruction, and healing of tendon-bone interface was accelerated.

Return to Baseline Physical Activity After Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts are the most utilized grafts for primary anterior cruciate ligament (ACL) reconstruction. The ability of a patient to return to a preinjury level of physical activity is a key consideration in choice of graft; the influence of graft choice on this metric lacks consensus in the literature.

PURPOSE

To assess the effects of autograft choice (BPTB vs HT) for primary ACL reconstruction on return to baseline level of physical activity and/or sports participation.

STUDY DESIGN

Meta-analysis; Level of evidence, 1.

METHODS

A systematic review of randomized controlled trials comparing the use of BPTB and HT autografts for primary ACL reconstruction was conducted. The electronic databases EMBASE, MEDLINE, Cochrane CENTRAL, and Web of Science were comprehensively queried through September 23, 2019. The primary outcome was return to preinjury level of activity/sports. Secondary outcomes included knee stability testing (Lachman, KT-1000 arthrometer, and pivot-shift tests) and clinical subjective knee scores (Tegner, Cincinnati, International Knee Documentation Committee, and Lysholm). Two independent reviewers were involved in the screening of titles and abstracts, data extraction, and the assessment of risk of bias. Meta-analyses were performed respecting the Cochrane Handbook for Systematic Reviews of Intervention.

RESULTS

A total of 29 studies (N = 3099 patients) were eligible for this review, of which 13 (n = 1029 patients) reported on return to baseline level of sports as an endpoint. The risk ratio (RR) of using BPTB vs HT on return to baseline sport level was 1.03 (0.91-1.17; P = .63). Absence of a positive pivot-shift test was the only secondary outcome, with a statistically significant RR of 0.66 (95% CI, 0.50-0.86) in favor of BPTB autografts (P = .002).

CONCLUSION

In reviewing the current literature, no recommendation can be made on the optimal graft choice when using a return to baseline level of physical activity and/or sports participation as a primary metric.

Biological enhancement methods may be a viable option for ACL arthroscopic primary repair - A systematic review

BACKGROUND

Bioactive factors combined with advanced anterior cruciate ligament (ACL) primary repair technology have been used to treat ACL repairs. The current review was conducted to identify whether biological enhancement could enable superior clinical outcome, including side-to-side difference, failure rate, reoperation rate and subjective scores.

HYPOTHESIS

The implementation of ACL primary repair with biological enhancement will provide better clinical outcomes in terms of side-to-side differences, failure rate, reoperation rate and subjective scores than ACL primary repair alone.

MATERIALS AND METHODS

A systematic literature review was performed following PRISMA guidelines by searching all studies reporting outcomes of arthroscopic primary repair with or without biological augmentation published until April 19, 2020, in Medline, PubMed, Embase and the Cochrane Library. Primary metrics were side-to-side differences, failure rate and reoperation rate, as well as measurements of patient-reported outcomes at the last follow-up.

RESULTS

A total of 20 studies were finally included in this work, of which 3 were Grade I (15%), 3 studies were Grade III (15%), and 14 studies were Grade IV (70%) in terms of the level of evidence. There were 729 patients with a mean age of 30 (range: 8-68) years, and the mean follow-up period of which was 38 (range: 3-122) months. At the final follow-up, the postoperative side-to-side differences (the proportion of patients with a side-to-side difference less than 3mm) and patient-report outcomes were significantly better in the biological enhancement group. Nevertheless, there were no significant differences between the two groups in the rate of surgical failure, the rate of revision, or the positive Lachman test or pivot shift test.

CONCLUSION

Biologically enhanced arthroscopic ACL primary repair was superior to ACL primary repair alone in terms of postoperative side-to-side differences (proportion of patients with a side-to-side difference less than 3mm) and patient-reported outcomes. Thus, biologically enhanced arthroscopic ACL primary repair can be preferentially recommended over ACL arthroscopic primary repair alone.

LEVEL OF EVIDENCE

IV, systematic review.

Bench to Bedside: A Multidisciplinary Approach toward the Unknowns after ACL Injuries to Drive Individual Success

ACL injury and surgery are increasing in prevalence. Several challenges exist that can be obstacles to an individual achieving success after ACL surgery. A knowledge of these risk factors alongside a multidisciplinary collaborative team approach can result in a greater likelihood of achieving individual success after ACL surgery.

Journey around the Notch: A Systematic Review on the History of ACL Reconstruction in the United States

The evolution of anterior cruciate ligament (ACL) surgery, seemingly circular at times, informs and provides context for past and current controversies in ACL management. The purpose of this systematic review is to objectively summarize the historical course of ACL reconstruction and repair in the United States over the last 40 years. Femoral tunnel drilling and graft selection have evolved dramatically over the last few decades. An initial focus on restoring ACL anatomy was for a period sacrificed for decreased operative morbidity. However, recent developments in operative techniques aim to restore ACL anatomy while also achieving minimal operative morbidity. Despite this historically iterative process, there remains no perfect choice for the treatment of ACL tears. Continued research on ACL repair, anatomic graft placement, graft choice, and augmentation will help our patients over the next generation.

Bone Grafting the Patellar Defect After Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction Decreases Anterior Knee Morbidity: A Systematic Review

PURPOSE

The aim of this systematic review was to evaluate the impact of bone grafting of patellar defects on reported anterior knee morbidity and subjective outcomes after bone-patellar tendon-bone autograft reconstruction of the anterior cruciate ligament.

METHODS

A systematic electronic search of MEDLINE, Embase, Web of Science, and the Cochrane Library was carried out. All English-language prospective randomized clinical trials published from January 1, 2000, to July 24, 2020, were eligible for inclusion. All studies addressing patellar defect grafting were eligible for inclusion regardless of the timing of surgery, graft type, surgical technique, or rehabilitation protocol.

RESULTS

A total of 39 studies with 1,955 patients were included for analysis. There were 796 patients in the no patellar grafting (NPG) group, with a mean age range of 22.7 to 33.0 years, and 1,159 patients in the patellar grafting (PG) group, with a mean age range of 17.8 to 34.7 years. The visual analog scale pain score ranged from 1.2 to 5.1 in the NPG group compared with 0.3 to 3.7 in the PG group. The proportion of patients with anterior knee pain ranged from 19% to 81% in the NPG group and from 15% to 32% in the PG group. Moderate to severe kneeling pain was reported in 22% to 57% of patients in the NPG group and 10% of those in the PG group. The percentage of patients with at least 3° of extension loss ranged from 4% to 43% in the NPG group and from 2% to 11% in the PG group.

CONCLUSIONS

PG favors decreased anterior knee pain, kneeling pain, and extension loss compared with non-grafted defects; however, the functional outcomes are comparable. Owing to the heterogeneity in reporting, statistical conclusions could not be drawn.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

The long-term outcomes of different grafts in anterior cruciate ligament reconstruction: a network meta-analysis

OBJECTIVES

To compare the long-term prognosis of patients with different types of grafts used in anterior cruciate ligament reconstruction (ACLR).

METHODS

PubMed, Ovid (MEDLINE and Embase) and the Cochrane library were searched up to Feb 2020. Eligible studies about different grafts in ACLR were searched for identifying the evidence comparing the long-term (mean or median follow-up time or the general description of the follow-up time≥2 years) knee outcomes of different grafts for ACLR. The final included articles and evaluation criteria were confirmed by the authors and senior clinicians to ensure the validity of the included articles. Lysholm score, the results of pivot shift test, Lachman test and International Knee Documentation Committee (IKDC) evaluation were selected as prognostic indicators. A Bayesian network meta-analysis was conducted.

RESULTS

A total of 30 articles were included in our network meta-analysis. Finally, we found that artificial graft or augmentation can provide the not bad Lysholm score but the worse result of IKDC evaluation for patients with ACLR compared with other types of grafts. Double-bundle hamstring autograft can provide a good Lysholm score as well as lower positive rate of pivot shift test and Lachman test. Patellar tendon autograft can provide the better result of IKDC evaluation. The patients with allogeneic tendon graft may get the higher positive rate of pivot shift test and Lachman test. Patients with single-bundle hamstring autograft may get the ordinary result of IKDC evaluation and Lysholm score.

CONCLUSIONS

Double-bundle hamstring autograft may be a better choice because of more items of good prognosis for the patients with ACLR. Patellar tendon autograft is a right choice which only shows the disadvantage on the Lysholm score. The prognosis of patients with single-bundle hamstring autograft is ordinary. The effect of artificial graft or augmentation needs more evidence to prove. Allogeneic tendon graft is not a better choice when compared with other grafts referred in our network meta-analysis.

TRANSLATIONAL POTENTIAL STATEMENT

In this study, we made a comprehensive comparison of the grafts commonly used in anterior cruciate ligament reconstruction. The evidence presented in this study provides a reference for clinicians to select a suitable anterior cruciate ligament graft.

Comparative Efficacy of Graft Options in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Network Meta-Analysis

Purpose

To evaluate the effectiveness of various graft options for anterior cruciate ligament reconstruction using network meta-analysis.

Methods

A medical literature search was conducted of PubMed, the Cochrane Library, Embase, SCOPUS, and Web of Science from their inception through March 1, 2019. The outcomes, including International Knee Documentation Committee (IKDC) form, Lachman test, Lysholm score, Pivot shift test, and Tegner score, were evaluated among graft options. Data extraction was carried out according to inclusion and exclusion criteria, and a network meta-analysis was performed using STATA 14.0.

Results

A total of 45 trials with 3992 patients were included. The forest plots revealed no significant differences in IKDC, Lysholm, or Tegner score among the grafts. In Lachman score, a significant difference was found in the comparisons of hamstring tendon allograft (HT-AL) versus patellar tendon autograft (PT-AU) and HT-AL versus hamstring tendon autograft (HT-AU). In pivot shift test, PT-AU was superior to all the other grafts, and quadriceps tendon autograft (QT-AU) was superior to HT-AL and artificial ligament (Art-L) in the number of cases with negative results. According to surface under the cumulative ranking area (SUCRA), PT-AU had the highest probability to be the best intervention in Lachman test and Tegner score; tibialis anterior tendon allograft (TA-AL) in IKDC and Lysholm score; and QT-AU in pivot shift test. Based on the cluster analysis of SUCRA, PT-AU was considered the most appropriate intervention by IKDC and Lachman test.

Conclusion

This study suggests that PT-AU may be the most appropriate graft for ACL reconstruction according to IKDC and Lachman test results.

Level of Evidence

Level I, network meta-analysis of randomized controlled trials.

Clinical Outcomes of the Central Third Patellar Tendon Versus Four-strand Hamstring Tendon Autograft Used for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Subgroup Meta-analysis of Randomized Controlled Trials

BACKGROUND

The most frequently used auto-grafts for ACL reconstruction (ACLR) are bone-patellar tendon-bone (BPTB) and four-strand hamstring tendon (4S-HT), but significant controversy exists about which graft is better. This study aimed to compare the knee outcomes following ACLR with BPTB and 4S-HT autografts.

METHODS

Subgroup meta-analyses were performed basing on available randomised controlled trials (RCTs) according to different follow-up intervals. 23 RCTs were eligible for inclusion, involving 933 participants in each treatment group.

RESULTS

Only short-term (≤2 years) knee anteroposterior and rotational stability were significantly poorer with 4S-HT when compared to BPTB autograft, as judged by side-to-side difference on knee laxity (WMD=-0.50, 95%CI -0.81~-0.18, p=0.002) and pivot-shift test (OR=0.58, 95%CI 0.39~0.88, p=0.010), respectively. The IKDC objective grade was evident to be in favour of 4S-HT group in mid-term (3-5 years) follow-up (OR=0.63, 95%CI 0.43~0.92, p=0.017). Several donor-site related complications, including anterior knee pain, pain with kneeling and extension deficit, were more frequent in BPTB autograft group, while lower short-term iskinetic peak flexion torques both at 60°/S (WMD=8.93, 95%CI 7.88~9.99, p<0.001) and 240°/S (WMD=11.63, 95%CI 9.92~13.34, p<0.001) were caused by HT harvesting.

CONCLUSION

BPTB was associated with inferior mid- to long-term (>5 years) knee functional outcomes, and increased frequency of donor-site complications. In contrast, only short-term knee laxity was increased for 4S-HT autograft, which is expected to be improved by providing more conservative rehabilitation protocol and aperture fixation methods.

Hamstring autograft versus patellar tendon autograft for anterior cruciate ligament reconstruction, which graft has a higher contralateral anterior cruciate ligament injury rate?: A meta-analysis of 5561 patients following the PRISMA guidelines

BACKGROUND

Contralateral anterior cruciate ligament (CACL) injury is one of the devastating complications after anterior cruciate ligament (ACL) reconstruction. Whether the risk of CACL tear is related to graft selection remains controversial due to contradictory results in studies. There are no meta-analyses to compare which graft has a higher CACL injury rate. Hence, this meta-analysis was conducted to compare the incidence of the CACL injury after ACL reconstruction with bone-patellar tendon-bone (BPTB) autografts compared with hamstring (HT) autografts.

METHODS

A comprehensive search of literature published between 1980 and January 2020 was performed using MEDLINE, EMBASE, Web of Science, and the Cochrane Library databases. RevMan 5.3 software was used for meta-analysis. The overall risk ratio (RR) was calculated using a fixed- or random-effects. The heterogeneity among the included results was analyzed by chi-square test with significance set at P < .10, and the heterogeneity was quantitatively detected by I-square tests.

RESULTS

Fifteen prospective comparative studies met inclusion criteria. In the BPTB group, the CACL rupture rate ranged from 1.8% to 30%, with a pooled percentage of 8.5%. In the HT group, the CACL rupture rate ranged from 0% to 14.4%, with a pooled percentage of 3.3%. The overall CACL rupture rate was 3.1% and ranged from 1.1% to 27.1%, with a pooled percentage of 4.9%. The pooled results indicate that there was a statistical significant difference in CACL rupture risk rate between BPTB and HT autograft. (RR, 1.53; 95% CL, 1.21-1.91; P = .0004).

CONCLUSION

This review showed that patients undergoing primary ACL reconstruction with BPTB autograft were more likely to have CACL rupture than patients treated with HT autograft.

Healthy knee KT1000 measurements of anterior tibial translation have significant variation

PURPOSE

The most commonly used arthrometer for measuring and reporting anterior tibial translation after anterior cruciate ligament reconstruction is the KT1000. Reports on its consistency and reproducibility vary in the literature, but it remains the "gold standard". The purpose of this study was to assess agreement of KT1000 measurements in a daily clinical setting.

METHODS

A retrospective analysis of anterior knee translation in the healthy knee of 770 patients over a 17-year time period was performed. In this cohort, a total of 24 investigators performed 1890 measurement sets at 89 Newtons (N), 134N and at maximum manual force (MMax) level. To assess the inter- and intra-observer agreement, the intraclass-correlation coefficient (ICC) was calculated. The "investigator effect" was a difference between two examiners in the same patient and the "device effect'' a difference within one examiner in the same patient. Minimally important difference (MID) was calculated as 0.5 of the standard deviation.

RESULTS

Thirteen investigators were female, performing 1099 measurements and 11 were male, performing 791 measurements. ICC ranged between 0.558 and 0.644. At the MMax level, male investigators had a higher mm reading than female investigators (p < 0.001). Increased experience did not correlate with a higher ICC. MID ranged between 0.85 and 1.65 mm.

CONCLUSION

This study investigated the KT1000 arthrometer in a clinical setting with a large number of investigators. This device delivers moderate agreement of results. Both the device and investigator effect are present. The MMax level has shown the lowest agreement and a dependency on the investigator gender.

LEVEL OF EVIDENCE

Level III diagnostic study.

All-Inside Quadrupled Semitendinosus Autograft Shows Stability Equivalent to Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: Randomized Controlled Trial in Athletes 24 Years or Younger

PURPOSE

To compare clinical outcomes of knee anterior cruciate ligament (ACL) autograft reconstruction using all-inside quadrupled semitendinosus (AIST) versus bone-patellar tendon-bone (BPTB) in a high-risk athletic population 24 years or younger.

METHODS

Skeletally mature candidates younger than 24 years old with an ACL tear were randomized into either the AIST (n = 32) or BPTB (n = 32) group and were followed for 2 years. Magnetic resonance imaging scans were obtained at 1-year follow-up, and radiographs were obtained at 2-year follow-up. All surgeries were performed by a single surgeon using an anteromedial portal to establish the femoral tunnel. The primary outcome measure was KT-1000 stability testing. Secondary outcome measures included International Knee Documentation Committee (IKDC) Knee Evaluation Form, IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx Activity Scale, visual analog pain scale, and SF-12 (Mental and Physical).

RESULTS

At 2-year follow-up, no statistical difference existed with KT-1000-measured side-to-side laxity between AIST (0.3 ± 0.7 mm, 95% confidence interval 0.0-1.0 mm) and BPTB (0.0 ± 0.8 mm, confidence interval CI -0.3 to 1.1 mm) (P = .197). In addition, no statistical differences between the groups were found for IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx, SF-12 Mental, SF-12 Physical, or with regards to imaging findings. Patients with BPTB reported significantly greater postoperative pain scores at days 2 (P = .049), 3 (P = .004), and 7 (P = .015) and had significantly greater kneeling pain at 2 years (P < .019). A return to sport questionnaire at 2 years revealed no significant difference between the groups for returning to preoperative level of sport activity (83% AIST, 74% BPTB; P = .415). Two graft retears (7%; P = .222) occurred in the AIST group. Three patients in the BPTB group experienced ACL tears in the contralateral knee (9%; P = .239).

CONCLUSIONS

ACL reconstruction with an all-inside quadrupled semitendinosus autograft construct is equivalent to patellar BPTB autograft based on KT-1000 stability testing in athletes 24 years or younger.

LEVEL OF EVIDENCE

randomized controlled trial with 92% 2-year follow-up, Level I.

Quadriceps tendon autograft for primary ACL reconstruction: a Bayesian network meta-analysis

Background

The purpose of the current study was to clarify the role of the quadriceps tendon (QT) autograft for primary ACL reconstruction. Thus, a Bayesian network meta-analysis comparing patients undergoing a primary ACL reconstruction with QT versus patellar tendon (PT) and hamstring tendon (HT) autografts was conducted.

Material and methods

This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of health care interventions. In January 2020, the main databases were accessed. Articles comparing the outcomes of the QT autograft versus HT autograft and/or PT autograft for primary ACL reconstruction were included in the present study. The statistical analysis was performed with STATA Software/MP, through a Bayesian hierarchical random-effect model analysis.

Results

Data from a total of 2603 knees were analysed. The overall mean follow-up was 35.0 months. Among the different grafts were evidenced comparable values of IKDC, Tegner and Lysholm score. The QT autograft detected comparable rate of Lachman test > 3 mm, Pivot shift test > 3 m and instrumental laxity > 3 mm. The QT autograft showed a lower rate of autograft failure above all. The QT autograft detected the reduced rate of AKP than the PT.

Conclusion

Quadriceps tendon autograft may represent a feasible option for primary ACL reconstruction. These results must be interpret within the limitations of the present network meta-anlaysis.

Effect of Graft Choice on Revision and Contralateral Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

BACKGROUND

The patellar tendon is often considered the "gold standard" graft for reducing the risk of graft rupture after anterior cruciate ligament (ACL) reconstruction. However, its use may also be associated with an increased risk of injury to the contralateral ACL.

PURPOSE

To clarify the association between graft choice and the risk of revision and contralateral ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Prospective data captured by the New Zealand ACL Registry between April 2014 and December 2018 were reviewed. All primary ACL reconstructions performed using either a hamstring tendon or patellar tendon autograft were included. Cox regression survival analysis adjusting for patient factors was performed to compare the risk of revision and contralateral ACL reconstruction between the hamstring tendon graft and the patellar tendon graft.

RESULTS

A total of 7155 primary ACL reconstructions were reviewed, of which 5563 (77.7%) were performed using a hamstring tendon graft and 1592 (22.3%) were performed using a patellar tendon graft. Patients with a hamstring tendon graft had a revision rate of 2.7% compared with 1.3% in patients with a patellar tendon graft (adjusted hazard ratio [HR], 2.51; 95% CI, 1.55-4.06; P < .001). The patellar tendon graft was associated with an increased risk of contralateral ACL reconstruction compared with the hamstring tendon graft (adjusted HR, 1.91; 95% CI, 1.15-3.16; P = .012). The number needed to treat (NNT) with a patellar tendon graft to prevent 1 revision was 73.6. However, the NNT with a hamstring tendon graft to prevent 1 contralateral reconstruction was 116.3.

CONCLUSION

Use of a patellar tendon graft reduced the risk of graft rupture but was associated with an increased risk of injury to the contralateral ACL. Adequate rehabilitation and informed decision making on return to activity and injury prevention measures may be important in preventing subsequent injury to the healthy knee.

Bone-Patellar Tendon-Bone Autografts Versus Hamstring Autografts Using the Same Suspensory Fixations in ACL Reconstruction: A Systematic Review and Meta-analysis

Background:

Bone–patellar tendon–bone (BPB) autografts and hamstring tendon (HT) autografts are 2 popular choices for anterior cruciate ligament reconstruction (ACLR). Although existing meta-analyses have explored the clinical outcomes between BPB and HT autografts, none have based their analysis on studies with just femoral suspensory fixation methods.

Purpose:

To evaluate and compare clinical outcomes, particularly graft failure and knee stability, of ACLR with BPB or HT autografts with suspensory femoral fixation.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A literature search was conducted of studies reporting single-bundle ACLR with BPB autografts and HT autografts with suspensory fixation with a minimum 24-month follow-up. Graft failure rate, knee stability, and clinical outcomes were compared for BPB versus HT autografts. Knee stability was measured with the Lachman test, pivot-shift test, and KT-1000/2000 arthrometer side-to-side difference (SSD). Clinical outcomes were measured with Lysholm scores and the Tegner activity scale, as well as rate of return to preinjury sports. Donor site morbidity among included studies was reviewed. A random-effects model was used for calculations of summary estimates. Subgroup, sensitivity, and trial sequential analyses were conducted.

Results:

Five studies were included. Graft failure was seen more often in the HT group than the BPB group, and this was statistically significant (P = .03). However, the trial sequential analysis outcome indicated that the included sample size was not large enough to support a solid positive finding. The analysis showed no significant difference in SSD, Lachman test, pivot-shift test, rate of return to sports, Lysholm score, or Tegner score between groups. Subgroup analyses found no significant difference between groups.

Conclusion:

This meta-analysis demonstrated no significant differences in knee stability and knee functional outcomes between BPB and HT autografts with suspensory fixation. More evidence is needed to prove the lower risk of failure with use of BTB autograft with suspensory fixation.

Bridge-Enhanced Anterior Cruciate Ligament Repair: Two-Year Results of a First-in-Human Study

Background

Bridge-enhanced anterior cruciate ligament repair (BEAR) combines suture repair of the anterior cruciate ligament (ACL) with a specific extracellular matrix scaffold (the BEAR scaffold) that is placed in the gap between the torn ends of the ACL to facilitate ligament healing.

Purpose/Hypothesis

The purpose of this study was to report the 12- and 24-month outcomes of patients who underwent the BEAR procedure compared with a nonrandomized concurrent control group who underwent ACL reconstruction (ACLR) with an autograft. We hypothesized that the BEAR group would have physical examination findings, patient-reported outcomes, and adverse events that were similar to those of the ACLR group.

Study Design

Cohort study; Level of evidence, 2.

Methods

Ten patients underwent BEAR, and 10 underwent ACLR with a 4-stranded hamstring autograft. At 24 months, 9 of the 10 BEAR patients and 7 of the 10 ACLR patients completed a study visit. Outcomes reported included International Knee Documentation Committee (IKDC) subjective and objective results, knee anteroposterior (AP) laxity findings via an arthrometer, and functional outcomes.

Results

There were no graft or repair failures in the first 24 months after surgery. The IKDC subjective scores in both groups improved significantly from baseline (P < .0001) at 12 and 24 months, to 84.6 ± 17.2 in the ACLR group and to 91.7 ± 11.7 in the BEAR group. An IKDC objective grade of A (normal) was found in 44% of patients in the BEAR group and in 29% of patients in the ACLR group at 24 months; no patients in either group had C (abnormal) or D (severely abnormal) grades. Arthrometer testing demonstrated mean side-to-side differences in AP laxity that were similar in the 2 groups at 24 months (BEAR, 1.94 ± 2.08 mm; ACLR, 3.14 ± 2.66 mm). Functional hop testing results were similar in the 2 groups at 12 and 24 months after surgery. Hamstring strength indices were significantly higher in the BEAR group compared with the ACLR group (P = .0001).

Conclusion

In this small, first-in-human study, BEAR produced similar outcomes to ACLR with a hamstring autograft. BEAR may result in knee stability and patient-reported outcomes at 2 years sufficient to warrant longer term studies of efficacy in larger groups of patients.

Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review

Objective

To describe the criteria used to guide clinical decision-making regarding when a patient is ready to return to running (RTR) after ACL reconstruction.

Design

Scoping review.

Data sources

The MEDLINE (PubMed), EMBASE, Web of Science, PEDro, SPORTDiscus and Cochrane Library electronic databases. We also screened the reference lists of included studies and conducted forward citation tracking.

Eligibility criteria for selecting studies

Reported at least one criterion for permitting adult patients with primary ACL reconstruction to commence running postoperatively.

Results

201 studies fulfilled the inclusion criteria and reported 205 time-based criteria for RTR. The median time from when RTR was permitted was 12 postoperative weeks (IQR=3.3, range 5–39 weeks). Fewer than one in five studies used additional clinical, strength or performance-based criteria for decision-making regarding RTR. Aside from time, the most frequently reported criteria for RTR were: full knee range of motion or >95% of the non-injured knee plus no pain or pain <2 on visual analogue scale; isometric extensor limb symmetry index (LSI)>70% plus extensor and flexor LSI>70%; and hop test LSI>70%.

Conclusions

Fewer than one in five studies reported clinical, strength or performance-based criteria for RTR even though best evidence recommends performance-based criteria combined with time-based criteria to commence running activities following ACL reconstruction.

Meta-analysis of the Risk of Infections After Anterior Cruciate Ligament Reconstruction by Graft Type

BACKGROUND

An infection after anterior cruciate ligament (ACL) reconstruction is a relatively rare but challenging complication. There are no meta-analyses comparing the incidence of infections after ACL reconstruction with the various available graft choices.

PURPOSE

To compare the incidence of infections after ACL reconstruction with bone-patellar tendon-bone (BPTB) autografts compared with hamstring autografts, with a secondary aim of comparing the incidence of infections after reconstruction with autografts compared with allografts.

STUDY DESIGN

Meta-analysis.

METHODS

A systematic review was performed to identify level 1 and 2 studies that reported the incidence of infections by graft type after ACL reconstruction. Studies that evaluated patients undergoing primary ACL reconstruction with an autograft, allograft, or combination of autograft and allograft and reported the number of postoperative infections by graft type utilized were considered for inclusion. Studies were excluded if they included revision ACL reconstruction or did not specify the number of infections by graft type. Study findings were reviewed, and meta-analysis was performed when data were sufficiently homogeneous.

RESULTS

Twenty-one studies meeting criteria were identified from the literature review. Meta-analysis revealed a significant difference in the incidence of deep infections between BPTB autografts and hamstring autografts, with the BPTB group displaying a 77% lower incidence of infections compared with the hamstring group (relative risk [RR], 0.23; 95% CI, 0.097-0.54). The incidence of infections was 66% lower with BPTB autografts compared with all other graft types, with a pooled RR of 0.33 (95% CI, 0.15-0.71). There was no significant difference in the incidence of infections after ACL reconstruction with autografts compared with allografts (RR, 1.035; 95% CI, 0.589-1.819).

CONCLUSION

The findings of this meta-analysis demonstrate a significantly lower incidence of deep infections after ACL reconstruction with BPTB autografts compared with hamstring autografts but not compared with allografts.

CLINICAL RELEVANCE

Although the overall infection rate after ACL reconstruction is relatively low, the significantly higher rate of infections with hamstring autografts compared with BPTB autografts should be a consideration when discussing graft choices for ACL reconstruction.

Quadriceps Tendon-Bone or Patellar Tendon-Bone Autografts When Reconstructing the Anterior Cruciate Ligament: A Meta-analysis

OBJECTIVE

We aimed to quantitatively assess the outcomes of studies, comparing the use of Bone-patellar tendon-bone (BPTB) and the quadriceps tendon-bone (QTB) autografts when reconstructing the anterior cruciate ligament (ACL).

DATA SOURCES

MEDLINE, Embase, and CINAHL databases were searched for relevant articles published between January 1980 and January 2015 for the purpose of identifying studies comparing BPTB and QTB autografts for ACL reconstruction. Included studies were assessed regarding their methodological quality before analysis. Outcomes analyzed were graft failure rates, objective and subjective stability assessments, as well as the presence and severity of donor site morbidity.

MAIN RESULTS

Five studies contributed to the quantitative analysis of 806 patients with 452 patients included in the BPTB group and 354 patients in the QTB group. Graft failure rates were similar between the 2 groups [odds ratio (OR) = 0.61; confidence interval (CI) = 0.17-2.15; Z = 0.78, P = 0.44]. There were no significant differences between the 2 groups when testing anteroposterior stability using an arthrometer (standardized mean difference = 0.07; CI = -0.12-0.25; Z = 0.70, P = 0.48). At 1 year postoperatively, there was no difference in the percentage of patients with a positive pivot shift test between the 2 groups (OR = 1.0; CI = 0.85-1.18; Z = 0.01, P = 0.99). However, significantly less patients had graft site pain 1 year after surgery in the QTB group (OR = 0.10; CI = 0.02-0.43; Z = 3.12, P = 0.002). Similarly, fewer patients reported moderate to severe pain while kneeling, in the QTB group (OR = 0.16; CI = 0.07-0.37; Z = 4.26, P < 0.001).

CONCLUSIONS

This study demonstrates comparable survival rates and joint stability when BPTB and QTB grafts are used. However, fewer adverse donor site symptoms are evident with QTB grafts.

LEVEL OF EVIDENCE

III.

Reinterventions after dynamic intraligamentary stabilization in primary anterior cruciate ligament repair

BACKGROUND

The goal of this study was to perform an in-depth analysis of the frequency and cause of secondary interventions subsequent to primary anterior cruciate ligament (ACL) repair with dynamic intraligamentary stabilization (DIS).

METHODS

Between July 2009 and June 2014, 455 patients underwent DIS treatment. The minimum follow-up was 21months (mean 28months, range 21-64months).

RESULTS

A total of 215 (48.2%) reinterventions were performed in 190 (42.6%) patients. One-hundred and seventy-six (39.4%) were non-revision reinterventions, and 39 (8.7%) were revision ACL reconstructions. Re-arthroscopies included 26 (5.8%) scar tissue debridements with hardware removal due to range of motion deficits, 14 (3.1%) partial meniscectomies, four (0.9%) meniscal sutures, and four (0.9%) arthroscopies due to crepitation or knee pain. Minor non-revision reinterventions performed under analgosedation consisted of 97 (21.7%) hardware removals, 20 (4.5%) hardware removals with manipulations under anesthesia, and four manipulations under anesthesia alone (0.9%).

CONCLUSIONS

In our study, the revision rate was within the range of published results after ACL reconstructions. In over 90% of patients, the native ACL was preserved with no need for a secondary reconstruction. Most of the non-revision reinterventions were minor and included hardware removals and manipulations under anesthesia. The re-arthroscopy rate was lower than that after ACL reconstruction with fewer secondary meniscal sutures and partial meniscectomies. Early treatment of meniscal tears may be one crucial benefit of ACL repair with DIS.

Hamstring Autograft versus Patellar Tendon Autograft for ACL Reconstruction: Is There a Difference in Graft Failure Rate? A Meta-analysis of 47,613 Patients

BACKGROUND

Bone-patellar tendon-bone (bone-tendon-bone) and four-strand hamstring tendon grafts (hamstring) are the most commonly utilized autografts for primary anterior cruciate ligament (ACL) reconstruction. Existing clinical trials, registry studies, and meta-analyses offer conflicting opinions regarding the most favorable graft choice.

QUESTIONS/PURPOSES

Which graft type for ACL reconstruction (bone-tendon-bone or hamstring) has a higher risk of (1) graft rupture and/or (2) graft laxity?

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs), prospective cohort studies, and high-quality national registry studies to compare the outcomes of primary ACL reconstruction with bone-tendon-bone autograft or hamstring autograft. Studies that compared these graft types were identified through a comprehensive search of electronic databases (PubMed, MEDLINE, EMBASE, and the Cochrane Library). Two independent reviewers utilized the Jadad scale for RCT study quality and the Modified Coleman Methodology Score for prospective comparative and registry study quality. The included studies were analyzed for the primary outcome measure of graft rupture with or without revision ACL surgery. In surviving grafts, secondary outcomes of graft laxity were quantified by KT1000/2000™ testing, a positive pivot shift test, and a positive Lachman test. Meta-analysis was performed with Review Manager. A total of 47,613 ACL reconstructions (39,768 bone-tendon-bone and 7845 hamstring) from 14 RCTs, 10 prospective comparative studies, and one high-quality national registry study were included in this meta-analysis. Mean age was 28 years in both groups. Sixty-three percent of patients in the bone-tendon-bone cohort were men versus 57% of patients in the hamstring cohort. Mean followup was 68 ± 55 months.

RESULTS

Two hundred twelve of 7560 (2.80%) bone-tendon-bone grafts ruptured compared with 1123 of 39,510 (2.84%) in the hamstring group (odds ratio = 0.83, 95% confidence interval, 0.72-0.96; p = 0.01). The number needed to treat analysis found that 235 patients would need to be treated with a bone-tendon-bone graft over a hamstring tendon graft to prevent one graft rupture. Instrumented laxity analysis showed that 22% (318 of 1433) of patients in the bone-tendon-bone group had laxity compared with 18% (869 of 4783) in the hamstring tendon group (odds ratio = 0.86; p = 0.16). Pivot shift analysis showed a positive pivot shift in 19% (291 of 1508) of the bone-tendon-bone group compared with 17% (844 of 5062) in the hamstring group (odds ratio = 0.89; p = 0.51). Lachman testing showed a positive Lachman in 25% (71 of 280) of patients receiving bone-tendon-bone grafts compared with 25% (73 of 288) in the hamstring group (odds ratio = 0.96; p = 0.84).

CONCLUSIONS

In this meta-analysis of short- to mid-term followup after primary ACL reconstruction, hamstring autografts failed at a higher rate than bone-tendon-bone autografts. However, failure rates were low in each group, the difference observed was small, and we observed few differences between graft types in terms of laxity. Both graft types remain viable options for primary ACL reconstruction, and the difference in failure rate should be one part of a larger conversation with each individual patient about graft selection that should also include potential differences in donor site morbidity, complication rates, and patient-reported outcome measures. Continued prospective collection of patient data will be important going forward as we attempt to further characterize the potential differences in outcomes attributable to graft selection.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Functional performance 2-9 years after ACL reconstruction: cross-sectional comparison between athletes with bone-patellar tendon-bone, semitendinosus/gracilis and healthy controls

PURPOSE

The purpose of this cross-sectional study was to provide descriptive data on functional performance in men and women with ACLR, to compare bone-patellar tendon-bone (BPTB) with semitendinosus/gracilis (STG) within the same sex and to compare the ACLR subjects with healthy controls.

METHODS

Eligible participants comprised 100 men (43 % BPTB) and 84 women (41 % BPTB) after ACLR, of whom 30 men (STG n = 19; BPTB n = 11) and 18 women (STG n = 12; BPTB n = 6) were untraceable/not willing and 15 men (STG n = 9; BPTB n = 6) and 18 women (STG n = 12; BPTB n = 3) were not able to take part in the measurements because of injury. Besides men BPTB (n = 24), men STG (n = 27), women BPTB (n = 23) and women STG (n = 23), healthy men (n = 22) and women (n = 22) participated. Measurements consisted of questionnaires, isokinetic peak torque and endurance tests, a hop test battery and drop jump including video analysis.

RESULTS

Only the occurrence of dynamic knee valgus differed between ACLR and healthy subjects.

CONCLUSION

Two to nine years after ACLR, 16 % of athletes could not participate because of a lower extremity injury. In the remaining group, this study showed similar results for males and females with BPTB compared with STG. Also, similar results are found for quantity of movement comparing operated and healthy subjects. For quality of movement, only the occurrence of dynamic knee valgus in landing from a jump is higher in operated subjects compared with healthy controls. This supports the relevance of a focus on quality of movement as part of ACLR rehabilitation programmes and return to sports criteria.

LEVEL OF EVIDENCE

III.

Outcome of Patellar Tendon Versus 4-Strand Hamstring Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Prospective Randomized Trials

PURPOSE

To compare clinical outcomes of anterior cruciate ligament (ACL) reconstruction and investigate whether the clinical results of 4-strand hamstring tendon (HT) reconstruction are still inferior to that of the patellar tendon (PT).

METHODS

We performed a comprehensive systematic review and meta-analysis of the English literature on PubMed, Scopus, Web of Science, and the Cochrane register for papers that compared clinical outcomes of PT versus HT for ACL reconstruction. Outcome measures analyzed included rate of rerupture, KT-1000, International Knee Documentation Committee grade, Lachman, pivot shift, Lysholm score, Tegner Activity Scale, anterior knee pain, and discomfort on kneeling.

RESULTS

We included 19 studies from an initial 1,168 abstracts for the systematic review, and, eventually, 19 studies were included in the meta-analysis. The study population consisted of a total of 1784 patients. The average follow-up duration was 58.8 months. We found significant differences in favor of the HT technique in the domains of anterior knee pain, kneeling pain, and restriction in the range of active extension ("extension deficit"). We found no differences between the PT and HT technique in terms of rerupture rate. There were no clinically significant differences for the outcomes of Lysholm score and Tegner Activity Scale as well as the KT-1000 side-to-side at maximum manual force.

CONCLUSIONS

Contemporary 4-strand HT ACL reconstruction is comparable with the PT technique in terms of clinical stability and postoperative functional status across most parameters studied. The HT technique carries lower risk of postoperative complications such as anterior knee pain, kneeling discomfort, and extension deficit. Primary ACL reconstruction using the 4-strand HT technique achieves clinical results that are comparable with the PT technique with significantly less postoperative complications.

LEVEL OF EVIDENCE

Level I, systemic review and meta-analysis of Level I studies.

Credibility and quality of meta-analyses addressing graft choice in anterior cruciate ligament reconstruction: a systematic review

PURPOSE

This systematic review examined the methodological credibility and quality of reporting of all meta-analyses which have compared bone-patellar tendon-bone (BPTB) versus hamstring tendon (HT) for anterior cruciate ligament (ACL) reconstruction (ACLR).

METHODS

EMBASE, MEDLINE, and The Cochrane Library were systematically searched, and two reviewers independently assessed eligibility, credibility according to the Users' Guide to medical literature, and completeness of reporting according to the preferred reporting items for systematic review and meta-analyses (PRISMA) checklist. Inter-rater agreement was quantified using Kappa, and we used Pearson's correlation coefficient to evaluate potential associations.

RESULTS

Seventeen meta-analyses were identified comparing BPTB versus HT for ACLR. The majority of meta-analyses were published in 2011 (5; 29 %), and North America was the most common continent of publication (6; 35 %). The three most commonly reported outcomes were stability (82 %), complications (76 %), and function (return to sport, IKDC score) (71 %). The median number of satisfactorily reported items in the Users' Guide was three out of seven (IQR 2-4). The median number of satisfactorily reported items in PRISMA for the meta-analyses was 20 out of 27 (IQR 19-22).

CONCLUSION

The credibility of the meta-analyses comparing BPTB versus HT autograft for ACLR although limited is improving with time. Earlier studies had limited methodological rigour; however, the more recent studies have shown promise in improved methodology. The study findings suggest that decisions should be made on a case-to-case basis with coordination of patient factors and preferences as well as surgeon experience on the background of the best available evidence.

LEVEL OF EVIDENCE

IV.

Contractile function and motor unit firing rates of the human hamstrings

Neuromuscular properties of the lower limb in health, aging, and disease are well described for major lower limb muscles comprising the quadriceps, triceps surae, and dorsiflexors, with the notable exception of the posterior thigh (hamstrings). The purpose of this study was to further characterize major muscles of the lower limb by comprehensively exploring contractile properties in relation to spinal motor neuron output expressed as motor unit firing rates (MUFRs) in the hamstrings of 11 (26.5 ± 3.8) young men. Maximal isometric voluntary contraction (MVC), voluntary activation, stimulated contractile properties including a force-frequency relationship, and MUFRs from submaximal to maximal voluntary contractile intensities were assessed in the hamstrings. Strength and MUFRs were assessed at two presumably different muscle lengths by varying the knee joint angles (90° and 160°). Knee flexion MVCs were 60-70% greater in the extended position (160°). The frequency required to elicit 50% of maximum tetanic torque was 16-17 Hz. Mean MUFRs at 25-50% MVC were 9-31% less in the biceps femoris compared with the semimembranosus-semitendinosus group. Knee joint angle (muscle length) influenced MUFRs such that mean MUFRs were greater in the shortened (90°) position at 50% and 100% MVC. Compared with previous reports, mean maximal MUFRs in the hamstrings are greater than those in the quadriceps and triceps surae and somewhat less than those in the tibialis anterior. Mean maximal MUFRs in the hamstrings are influenced by changes in knee joint angle, with lower firing rates in the biceps femoris compared with the semimembranosus-semitendinosus muscle group.

NEW & NOTEWORTHY

We studied motor unit firing rates (MUFRs) at various voluntary contraction intensities in the hamstrings, one of the only major lower limb muscles to have MUFRs affected by muscle length changes. Within the hamstrings muscle-specific differences have greater impact on MUFRs than length changes, with the biceps femoris having reduced neural drive compared with the semimembranosus-semimembranosus. Comparing our results to other lower limb muscles, flexors have inherently higher firing rate compared with extensors.

Failure Rate and Clinical Outcomes of Anterior Cruciate Ligament Reconstruction Using Autograft Hamstring Versus a Hybrid Graft

PURPOSE

To compare the revision rate and subjective outcome measures of autograft hamstring versus a soft tissue hybrid graft combining both autograft hamstring and tibialis allograft for isolated anterior cruciate ligament (ACL) reconstruction.

METHODS

A single-center retrospective, nonrandomized, comparative study of isolated ACL reconstruction revision rates for subjects who underwent arthroscopic reconstruction of the ACL using autograft hamstring or a soft tissue hybrid graft using both autograft hamstring and tibialis allograft was performed. Patients with isolated ACL tears were included and underwent anatomic single-bundle reconstruction using an independent tunnel drilling technique and a minimum of 24 months' follow-up. The primary outcome assessed was the presence or absence of ACL rerupture. Secondary clinical outcomes consisted of the International Knee Documentation Committee, University of California at Los Angeles (UCLA) ACL quality of life assessment, and the visual analog pain scale.

RESULTS

Between February 2010 and April 2013, 95 patients with isolated ACL tears between ages 18 and 40 met the inclusion criteria and were enrolled. Seventy-one autograft hamstring and 24 soft tissue hybrid graft ACL reconstructions were performed during the course of this study. The follow-up period was 24 to 32 months (mean 26.9 months). There were no statistically significant differences in patient demographics or Outerbridge classification. No statistically significant differences in ACL retears (5.6% auto, 4.2% hybrid; P = .57) were found between groups. Clinical International Knee Documentation Committee and UCLA ACL quality of life assessment improvement scores revealed no statistically significant differences in autograft and hybrid graft reconstructions (41 ± 11, 43 ± 13; P = .65) (38 ± 11, 40 ± 10; P = .23). The mean pain level decreased from 8.1 to 2.8 in the autograft group and 7.9 to 2.5 in the hybrid group (P = .18).

CONCLUSIONS

The use of a hybrid soft tissue graft has a comparable rerupture rate and clinical outcome to ACL reconstruction using autograft hamstring.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Is There a Difference in Graft Motion for Bone-Tendon-Bone and Hamstring Autograft ACL Reconstruction at 6 Weeks and 1 Year?

BACKGROUND

Bone-patellar tendon-bone (BTB) grafts are generally believed to heal more quickly than soft tissue grafts after anterior cruciate ligament (ACL) reconstruction, but little is known about the time course of healing or motion of the grafts within the bone tunnels.

HYPOTHESIS

Graft-tunnel motion will be greater in hamstring (HS) grafts compared with BTB grafts and will be less at 1 year than at 6 weeks.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve patients underwent anatomic single-bundle ACL reconstruction using HS or BTB autografts (6 per group) with six 0.8-mm tantalum beads embedded in each graft. Dynamic stereo x-ray images were collected at 6 weeks and 1 year during treadmill walking and stair descent and at 1 year during treadmill running. Tibiofemoral kinematics and bead positions were evaluated. Graft-tunnel motion was based on bead range of motion during the loading response phase (first 10%) of the gait cycle.

RESULTS

During treadmill walking, there was no difference in femoral tunnel or tibial tunnel motion between BTB or HS grafts at 6 weeks (BTB vs HS: 2.00 ± 1.05 vs 1.25 ± 0.67 mm [femoral tunnel]; 1.20 ± 0.63 vs 1.27 ± 0.71 mm [tibial tunnel]), or 1 year (BTB vs HS: 1.62 ± 0.76 vs 1.08 ± 0.26 mm [femoral tunnel]; 1.58 ± 0.75 vs 1.68 ± 0.53 mm [tibial tunnel]). During stair descent, there was no difference in femoral or tibial tunnel motion between BTB and HS grafts at 6 weeks or 1 year. With running, there was no difference between graft types at 1 year. For all results, P values were > .05. Knee kinematics were consistent with the literature.

CONCLUSION

During walking and stair descent, ACL reconstruction using suspensory fixation yielded no difference between graft types in femoral or tibial tunnel motion at 6 weeks or 1 year. All subjects were asymptomatic with knee kinematics similar to that of the literature. The significance of persistent, small (1 to 3 mm) movements at 1 year for healing or graft performance is unknown.

CLINICAL RELEVANCE

These study results may have significant implications for graft choice, rehabilitation strategies, and timing for return to sports.

The Development and Early to Midterm Findings of the Multicenter Revision Anterior Cruciate Ligament Study

Revision anterior cruciate ligament (ACL) reconstruction can present a series of unique challenges for the both the patient and the treating surgeon. The Multicenter ACL Revision Study (MARS) was established to identify the factors contributing to ACL graft failure and report on the outcomes following revision reconstruction. In this article we review the development and early to midterm findings of the MARS group.

The Association Between Serum Biomarkers of Collagen Turnover and Subsequent Anterior Cruciate Ligament Rupture

BACKGROUND

No study has attempted to associate the levels of preinjury serum biomarkers of collagen turnover with the subsequent risk of anterior cruciate ligament (ACL) injury.

HYPOTHESIS

Preinjury serum biomarkers of collagen turnover would be associated with the subsequent risk of ACL injury.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

We conducted a case-control study with 45 ACL-injured cases and 45 controls matched for sex, age, height, and weight. In addition to the matching criteria, controls had no history of major joint injury. Baseline preinjury serum samples were obtained from the Department of Defense Serum Repository for all subjects. Samples were assessed for 2 serum biomarkers of collagen synthesis (CPII and CS846) and 2 markers of collagen degradation (C1,2C and C2C) through commercially available enzyme-linked immunosorbent assay (ELISA) kits. All ELISAs were performed in triplicate. Conditional logistic regression models were used to analyze the data.

RESULTS

Univariate results suggested that both biomarkers for collagen degradation (C1,2C and C2C) were significantly associated with the subsequent likelihood of ACL injury. Serum C2C and C1,2C concentration at baseline were associated with odds ratios (ORs) of 2.05 (95% CI, 1.30-3.23; P = .001) and 3.02 (95% CI, 1.60-5.71; P = .002), respectively. Baseline serum CPII concentrations were also associated with subsequent ACL injury. Serum CPII concentration at baseline was associated with an OR of 4.41 (95% CI, 1.87-10.38; P = .001). Baseline serum CS846 levels approached significance (OR = 0.77; 95% CI, 0.57-1.03; P = .080). Multivariable models suggested that preinjury CPII and C2C concentrations at baseline are important indicators of subsequent ACL injury risk.

CONCLUSION

Preinjury differences in serum biomarker levels of collagen turnover suggest that collagen metabolism in individuals who go on to tear an ACL may be different when compared with a matched control group with no history of major joint injury. These differences may be reflective of different preinjury biochemical and/or biomechanical risk profiles or genetic factors that subsequently affect both collagen metabolism and ACL injury risk.

The Effect of Autologous Hamstring Graft Diameter on the Likelihood for Revision of Anterior Cruciate Ligament Reconstruction

BACKGROUND

Hamstring autografts for anterior cruciate ligament (ACL) reconstruction (ACLR) have become popular in the past 2 decades; however, it is difficult to predict the diameter of the harvested tendons before surgery. Previous biomechanical studies have suggested that a smaller graft diameter leads to a lower load to failure, but clinical studies looking at various predictors for failure, including graft size, have been inconclusive.

PURPOSE

To evaluate the relationship of hamstring graft diameter to ACL revision within a large cohort of patients, while controlling for sex, age, body mass index (BMI), and femoral and tibial fixation type.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A case-control study using patients registered in an ACLR registry was conducted. Revision was used as a marker for graft failure. A case was defined as a patient who underwent primary ACLR with a hamstring autograft that was revised during the study period (April 2006 to September 2012). Three controls, defined as patients who underwent primary ACLR with a hamstring autograft that was not revised, were matched to each of the cases according to age, sex, BMI, and femoral and tibial fixation type. Descriptive characteristics were employed, and conditional logistic regression was conducted to produce estimates of odds ratios and 95% CIs.

RESULTS

A total of 124 cases and 367 controls were identified. There were no significant differences between cases and controls in the distribution of sex (52.4% male vs 52.9% male, respectively; P = .932), median age (17.6 years [interquartile range (IQR), 15.9-20.4] vs 17.6 years [IQR, 15.9-20.4], respectively; P = .999), median BMI (23.4 kg/m(2) [IQR, 21.5-26.4] vs 23.4 kg/m(2) [IQR, 21.6-25.8], respectively; P = .954), femoral fixation (P = .459), and tibial fixation (P = .766). The mean (±SD) graft diameter was 7.9 ± 0.75 mm in the cases and 8.1 ± 0.73 mm in the controls. The likelihood of a patient needing revision ACLR in the study cohort was 0.82 times lower (95% CI, 0.68-0.98) for every 0.5-mm increase in the graft diameter from 7.0 to 9.0 mm.

CONCLUSION

In this study, within the range of 7.0 to 9.0 mm, there was a 0.82 times lower likelihood of being a revision case with every 0.5-mm incremental increase in graft diameter.

Change in Size of Hamstring Grafts During Preparation for ACL Reconstruction: Effect of Tension and Circumferential Compression on Graft Diameter

BACKGROUND

There is good consensus that anterior cruciate ligament (ACL) grafts should be pretensioned to remove creep prior to implantation, but the literature contains little information on the influence of graft preparation or circumferential compression on graft size. The purpose of this study was to investigate how the size of hamstring allografts changes as they are prepared for ACL reconstruction. We hypothesized that grafts decrease in diameter as they are prepared with both tension and circumferential compression. We also investigated the interrater reliability of graft diameter measurements during each step of graft preparation.

METHODS

Twenty pairs of fresh-frozen human hamstring tendons obtained from an allograft supplier were prepared in a standardized fashion for ACL reconstruction (suturing followed by longitudinal tensioning followed by circumferential compression followed by relaxation). Four blinded raters measured each graft in a sequential manner after each graft preparation step. Interrater reliability was assessed using the intraclass correlation coefficient ICC(2,1). The mean allograft diameter at each time point was calculated and compared across all time points using repeated-measures analysis of variance (ANOVA).

RESULTS

Subjecting the grafts to both tension and circumferential compression significantly decreased their mean diameter (to 7.38 mm compared with 8.28 mm at baseline; p = 0.044). Interrater reliability revealed almost perfect agreement at each measurement interval, with the ICC ranging from 0.933 to 0.961.

CONCLUSIONS

The average diameter of hamstring ACL grafts decreases by almost 1 mm after they are subjected to both tension and circumferential compression within a standard cylindrical sizing block.

CLINICAL RELEVANCE

Because ACL bone tunnels are drilled in 0.5-mm increments, preparing soft-tissue grafts with circumferential compression in addition to tension may allow creation of tunnels that are one to two incremental sizes smaller. This could permit less bone removal, which may be particularly applicable for certain reconstruction techniques such as pediatric, double-bundle, or revision ACL reconstruction, in which limited space is available for tunnel drilling.

Biomechanical and Computed Tomography Analysis of Adjustable Femoral Cortical Fixation Devices for Anterior Cruciate Ligament Reconstruction in a Cadaveric Human Knee Model

PURPOSE

To evaluate and compare two adjustable femoral cortical suspensory fixation devices used for anterior cruciate ligament reconstruction through a novel, direct computed tomography (CT) analysis metric and biomechanical laxity testing in a matched cadaveric human knee study.

METHODS

Anterior cruciate ligament reconstructions with bovine tendon grafts were performed using two adjustable femoral cortical suspensory fixation devices (RigidLoop Adjustable [DePuy Synthes Mitek, Raynham, MA] and TightRope [Arthrex, Naples, FL]) in 12 knees (6 matched pairs). A mechanical testing series was used to determine each knee's laxity in the intact condition. After reconstruction, each specimen was again tested for laxity and also imaged with CT. The laxity testing and CT imaging were then repeated after 1,000 cycles of anteroposterior loading on each knee to compare changes in laxity for the two fixation devices and to visualize changes in button-to-graft distance migration through a three-dimensional CT imaging method.

RESULTS

No significant differences were found between the two fixation groups' laxity measures after reconstruction (all P values ≥ .620) or after cycling (all P values ≥ .211) at any flexion angle. In addition, no significant differences were found between the two groups regarding button-to-graft distance migration (P = .773; mean, 0.61 ± 0.6 mm [95% confidence interval, -0.1 to 1.3 mm] in RigidLoop Adjustable group and 0.53 ± 0.6 mm [95% confidence interval, -0.1 to 1.2 mm] in TightRope group).

CONCLUSIONS

There were no significant differences between the two femoral cortical suspensory adjustable-loop devices regarding laxity outcomes or loop displacement as measured by button-to-graft distance migration.

CLINICAL RELEVANCE

Use of either of the adjustable-loop cortical suspensory devices in our analysis would appear to produce similar, acceptable laxity outcomes and minimal effects in terms of device-related loop displacement.

Cortical femoral suspensory fixation using screw post in anatomic single-bundle anterior cruciate ligament reconstruction: a prospective study and mid-term outcome results

PURPOSE

Cortical femoral suspensory fixation using screw post in ACLR has the advantage of allowing complete filling of the femoral tunnel with graft tissue. In addition, the low cost of the implants is an advantage in countries where cost is an issue of concern. The purpose of the current study was to evaluate the clinical functional outcome results of cortical femoral suspensory fixation using screw post at mid-term follow-up.

METHODS

Single surgeon single centre prospective case series study. Sixty two patients having complete ACL tears were included in the current study. Average follow-up was 52.6 months (range 38-68). Objective and subjective IKDC scores, Lysholm knee score, SF-36 score, VAS for patients' satisfaction, VAS for pain and Kellgren & Lawrence (K/L) classification of osteoarthritis were used for follow-up evaluation.

RESULTS

Objective IKDC score revealed that 59 patients had grade "A" and 3 had grade "B", while no single patient had neither grade "C" nor "D". The average Lysholm score was 90.7, average subjective IKDC was 89.5. Average SF-36 score was 94.8. The average VAS for operation satisfaction was 9.4. Average VAS for pain was 0.2. Forty six patients were classified as normal K/L classification, nine were grade "1", seven were grade "2". Comparing pre-operative and follow-up objective IKDC, subjective IKDC, Lysholm, SF-36, and VAS for pain scores revealed statistically significant differences (P-value <0.05).

CONCLUSION

Femoral suspensory fixation using screw post in ACLR showed excellent functional outcome results at mid-term follow-up.

Does retrograde tibial tunnel drilling decrease subchondral bone lesions during ACL reconstruction? A prospective trial comparing retrograde to antegrade technique

BACKGROUND

The main goal of this study was to assess iatrogenic subchondral bone lesions following three different anterior cruciate ligament (ACL) reconstruction techniques and their association with early postoperative pain.

METHODS

A multicenter prospective comparative study was conducted in 2012. Each center performed a specific ligamentoplasty technique: two used retrograde and the other antegrade tibial tunnel drilling. Peri- and postoperative analgesia and systematic early postoperative magnetic resonance imaging (MRI) protocols were standardized. The main assessment criterion was tibial subchondral lesions (microfractures or bone oedema) on MRI during the first postoperative week. Secondary criteria were the assessment of postoperative pain for two days using a Visual Analogical Scale (VAS 0-10) and consumption of analgesics.

RESULTS

Forty-three patients were included in three centers, 15 in the "antegrade group" and 28 in the "retrograde group", mean age is 32.5±9.1years, 14 women/29 men. All included patients underwent postoperative MRI. There were no subchondral tibial microfractures, but oedema was significantly more frequent in the antegrade group (p=0.0001). Tibial subchondral oedema was correlated to greater early postoperative pain (p=0.01). Multivariate analysis identified tibial tunnel diameter as an independent factor of early postoperative pain. The smaller the tibial tunnel diameter, the greater the mean early postoperative pain (≤8mm (18 patients) 3.4±1.5 vs. >8mm (25 patients) 1.8±1.7, p=0.004) and the more frequent the presence of edemas (10/18 vs. 2/25, p=0.001).

CONCLUSION

The present clinical study confirmed the benefit of retrograde tibial tunnel drilling for tibial subchondral bone lesions and showed a correlation between these lesions and early postoperative pain.

LEVEL OF EVIDENCE

II; therapeutic study - prospective cohort study.

Knee stability after arthroscopic anterior cruciate ligament reconstruction using the middle third of the patellar ligament and quadrupled hamstring tendons grafts - A two-year follow-up

Knee stability after surgical anterior cruciate ligament (ACL) reconstruction using quadrupled hamstring tendons graft (gracilis and semitendinosus) was compared with that using the middle third of the patellar ligament. All subjects participating in this study had ACL rupture diagnosed by clinical examination and MRI and underwent identical surgical procedure apart from the choice of graft. A total of 112 patients with either patellar ligament or quadrupled hamstring tendons graft were evaluated for 24 months following surgery. Patients were similar in terms of age, sex, activity level, knee instability level and rehabilitation programme. Clinical tests and a measuring instrument, the KT-1000 arthrometer, were used to evaluate knee stability after reconstruction. During the 24-month study there were no significant differences in clinical stability of the knee and the use of both grafts resulted in satisfactory knee stability. The difference between the groups according to the graft was noticed 6 months after reconstruction when the results obtained by a measuring instrument showed that knee stability was significantly higher with the patellar ligament graft (Fisher's exact test, p=0.022).

A two- and five-year follow-up of clinical outcome after ACL reconstruction using BPTB or hamstring tendon grafts: a prospective intervention outcome study

PURPOSE

The aim of the present study was to evaluate and compare objective and subjective outcome in patients 2 and 5 years after anterior cruciate ligament (ACL) reconstruction with either bone-patellar tendon-bone (BPTB) or hamstring grafts. The second aim was to report the prevalence of re- and contralateral ACL ruptures.

METHODS

Sixty-eight patients (BPTB, n = 34 and hamstring graft, n = 34) were evaluated preoperatively, 2 and 5 years after ACL reconstruction. Anterior knee laxity and rotational knee joint stability, muscle torque, hop length, anterior knee pain, activity level and self-reported knee function and quality of life were evaluated within and between groups. The prevalence of re- and contralateral ACL ruptures was also recorded.

RESULTS

No significant difference in anterior knee laxity, rotational knee joint stability, hop length anterior knee pain or knee function and quality of life were noted at the 5-year follow-up. No significant differences in concentric or eccentric quadriceps torque at 90°/s and 230°/s were found at any of the follow-ups between and within grafts. A significant group difference in hamstring torque 1.05 (0.02) for BPTB and 0.89 (0.02) for hamstring grafts, and in hop length (leg symmetry index) follow-up 0.94 (0.07) for BPTB compared to 0.99 (0.07) for hamstring grafts (P = 0.002) was found at the 2 year follow-up in favour of the BPTB graft, but not at the 5 year follow-up. A significant improvement over time, irrespective of graft, was found in the KOOS's subscales Sport/Rec and quality of life (P < 0.001). None of the patients, irrespective of group, returned to their pre-injury level of sport (P < 0.05). Over the five postoperative years, one man and eight women (13 %) (hamstring graft, n = 5 and BPTB graft, n = 4), sustained a total of 11 (16.2 %) new ACL ruptures: seven (10.2 %) re-ruptures and four (5.9 %) ruptures of the contralateral ACL.

CONCLUSIONS

At the 5-year follow-up, there were no significant differences in terms of anterior knee laxity, rotational knee joint stability, muscle torque, anterior knee pain, hop performance, quality of life or activity level between patients who had undergone reconstruction with BPTB or hamstring grafts. None of the patients, irrespective of group, had returned to their pre-injury level of activity. Eight out of the nine patients who had sustained a second ACL rupture were women.

A meta-analysis of bone-patellar tendon-bone autograft versus four-strand hamstring tendon autograft for anterior cruciate ligament reconstruction

BACKGROUND

There is a lack of comprehensive studies comparing the clinical outcome of anterior cruciate ligament (ACL) reconstruction with either a bone-patellar tendon-bone (BPTB) or four-strand hamstring tendon (4SHT) autografts. The optimal choice of graft for anterior cruciate ligament reconstruction remains controversial.

PURPOSE

The objective of this study was to evaluate the effectiveness of BPTB autografts versus 4SHT autografts for the reconstruction of ACL.

METHODS

A systematical search of literature was performed in Pubmed, Embase, and the Cochrane library to identify published clinical prospective studies relevant to ACL reconstruction comparing BPTB and 4SHT autografts. The results of the eligible studies were analysed in terms of instrumented laxity measurements, Lachman test, pivot shift test, objective International Knee Documentation Committee (IKDC) scores, return to preinjury activity level, and morbidity of graft failure, anterior knee pain, kneeling pain, extension deficit, and flexion deficit. Study quality was assessed by using the Jadad scale for randomized clinical trial (RCT) and the Newcastle-Ottawa Scale (NOS) for prospective cohort study (PCS). Two reviewers independently assessed each study for quality and extracted data. Subgroup analysis of the primary outcomes was conducted according to the type of study design (RCT or PCS).

RESULTS

Twenty-two studies, with 931 patients in the BPTB group and 999 patients in the 4SHT group, met the inclusion criteria. Fourteen studies were randomized controlled trials, and eight were prospective cohort studies. The results of the meta-analysis showed that there were no significant differences between BPTB and 4SHT in terms of instrumented laxity measurements (P=0.06), Lachman test (P=0.58), objective IKDC scores (P=0.31), graft failure (P=0.45), extension deficit (P=0.06) and flexion deficit (P=0.63). However, outcomes in favour of BPTB were found in terms of pivot shift test (P=0.01) and return to preinjury activity level (P=0.03); outcome measures that favours 4SHT included anterior knee pain (P<0.01) and kneeling pain (P<0.01). These findings were still robust during the sensitivity analysis. Results from subgroup analysis of the primary outcomes were consistent with the overall analysis.

CONCLUSION

Based on the results above, ACL reconstruction with BPTB autografts might be superior in resuming rotation stability of the knee joint and allow patients to return to higher levels of activity in comparison with 4SHT autografts. Whereas, postoperative complications of the knee joint were lower for 4SHT autografts than for BPTB autografts. There was insufficient evidence to identify which of the two types of grafts was significantly better for ACL reconstruction considering the limitations of this study. More high-quality randomized controlled trials with strictly specified inclusion criteria are highly required before drawing a reliable conclusion.

Femoral suspension devices for anterior cruciate ligament reconstruction: do adjustable loops lengthen?

BACKGROUND

Cortical suspension devices are commonly used for femoral graft fixation during anterior cruciate ligament (ACL) reconstructive surgery. Adjustable-length fixation devices provide technical advantages over fixed-length loops but may be more susceptible to lengthening during cyclic loading.

HYPOTHESIS

Both fixed-length and adjustable-length femoral cortical suspension devices would withstand ultimate loads greater than those normally experienced by the native ACL and would prevent clinically significant lengthening during prolonged cyclic loading.

STUDY DESIGN

Controlled laboratory study.

METHODS

Mechanical testing was performed on 3 ACL graft cortical suspensory devices by use of an extended cyclic loading (4500 cycles at 10-250 N) and pull-to-failure protocol. Two adjustable-length devices were additionally tested with the free suture ends tied.

RESULTS

Total displacement after 4500 cycles of tensioning at variable loads (expressed as mean ± SD) was 42.45 mm (±7.01 mm) for the Arthrex TightRope RT, 5.76 mm (±0.35 mm) for the Biomet ToggleLoc, and 1.34 mm (±0.03 mm) for the Smith & Nephew EndoButton CL Ultra (P < .001). The Arthrex TightRope reached clinical failure of 3 mm lengthening after fewer cycles (1349 ± 316) than the Biomet ToggleLoc (2576 ± 73) (P < .001). The Smith & Nephew EndoButton did not reach clinical failure during cyclic testing. With the free suture ends tied, after 4500 cycles, the Arthrex TightRope had a significant decrease in lengthening to 13.36 ± 1.86 mm (P < .037) There was also a significant difference in ultimate load between the TightRope (809.11 ± 52.94 N) and the other 2 constructs (P < .001).

CONCLUSION

The ultimate load of all graft-fixation devices exceeded the forces likely to be experienced in a patient's knee during the early postoperative rehabilitation period. However, the adjustable-length fixation devices experienced a clinically significant increase in loop lengthening during cyclic testing. This lengthening is partially caused by suture slippage into the adjustable-length loop.

CLINICAL RELEVANCE

Adjustable-length ACL graft cortical suspension devices lengthen under cyclic loads because free suture ends are pulled into the adjustable loop. This may allow for graft-fixation device lengthening during the acute postoperative period.

Comparison of hamstring tendon and patellar tendon grafts in anterior cruciate ligament reconstruction in a nationwide population-based cohort study: results from the danish registry of knee ligament reconstruction

BACKGROUND

The choice of graft for anterior cruciate ligament reconstruction (ACLR) remains controversial, and despite numerous studies, there is still an ongoing debate on this topic. The 2 most widely used grafts are the hamstring tendon and patellar tendon.

HYPOTHESIS

In this study, we hypothesized that the revision rate after primary ACLR is greater when using hamstring tendon grafts compared with patellar tendon grafts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

From the nationwide population-based Danish Knee Ligament Reconstruction Registry, we identified all primary ACLR procedures (n = 13,647) performed in Denmark between July 2005 and December 2011. The end point was revision ACLR. As other end points, we used objective measurements and patient-reported outcome scores. Revision rates and relative risk estimates for revision ACLR were calculated using Cox multiple regression.

RESULTS

The use of hamstring tendon grafts increased from 68% in 2005 to 85% in 2011. The cumulative revision rates for hamstring tendon grafts at 1 and 5 years were 0.65% (95% confidence interval [CI], 0.51%-0.82%) and 4.45% (95% CI, 3.94%-5.01%), respectively. For patellar tendon grafts, the revision rate was 0.16% (95% CI, 0.05%-0.50%) at 1 year and 3.03% (95% CI, 2.27%-4.05%) at 5 years. The adjusted overall relative risk of revision surgery in the hamstring tendon group compared with the patellar tendon group was 1.41 (95% CI, 1.03-1.92), and the adjusted relative risk of undergoing revision surgery performed after 1 and 5 years was 3.82 (95% CI, 1.20-12.2) and 1.90 (95% CI, 0.43-8.40), respectively.

CONCLUSION

In this population-based study, the use of hamstring tendon grafts in ACLR was associated with an increased risk of revision compared with patellar tendon grafts, in particular during the first year after surgery. These results demonstrate that both hamstring and patellar tendon grafts reveal good results after ACLR and suggest that graft selection should be based on an individual evaluation of patient demands and graft morbidity.

Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: a systematic review, meta-analysis, and meta-regression

BACKGROUND

While numerous cadaveric, in vivo, and clinical studies have compared transtibial and independent drilling of femoral tunnels during anterior cruciate ligament reconstruction, there is no evidence-based consensus on which technique affords the best outcome.

HYPOTHESIS

There is no difference in clinical outcome between transtibial and independent drilling of femoral tunnels.

STUDY DESIGN

Systematic review with meta-analysis and meta-regression.

METHODS

Cadaveric, in vivo, and clinical studies comparing transtibial and independent drilling techniques were systematically identified. A qualitative synthesis of nonrandomized studies and meta-analysis of randomized controlled trials (RCTs) were performed. In addition, a meta-regression analysis of RCTs that did not directly compare drilling techniques was performed.

RESULTS

A total of 49 studies were included in the qualitative review, and 15 were included in the meta-analysis; 22 studies were included in the meta-regression. In biomechanical studies, independent drilling placed the center of the femoral tunnel closer to the center of the femoral footprint (mean difference, 2.69 mm; 95% CI, 0.46-4.92; P < .00001). Independent drilling reduced anterior tibial translation with the Lachman examination (mean difference, 2.2 mm; 95% CI, 0.34-4.07; P = .02), 134 N of anterior load (mean difference, 1 mm; 95% CI, 0.29-1.71; P = .006), and simulated pivot shift (mean difference, 3.36 mm; 95% CI, 1.88-4.85; P < .00001). The meta-analysis showed improved Lysholm scores with independent drilling (mean difference, -0.62 points; 95% CI, -1.09 to -0.55; P = .009), although the clinical relevance of this small difference is questionable. There were no significant differences in International Knee Documentation Committee (IKDC) objective scores or Tegner scores between groups. With the meta-regression, there were no significant differences in failure rates or IKDC objective scores.

CONCLUSION

While there are biomechanical data suggesting improved knee stability and more anatomic graft placement with independent drilling, no significant clinical differences were found between the 2 techniques.

CLINICAL RELEVANCE

The current evidence shows that transtibial and independent drilling techniques have equivalent clinical outcomes at short-term to midterm follow-up. The long-term effects of subtle differences in tunnel position and postoperative knee kinematics should be further studied in dedicated, prospective cohort and randomized studies.

Bone-patellar tendon-bone autograft versus allograft in outcomes of anterior cruciate ligament reconstruction: a meta-analysis of 5182 patients

BACKGROUND

Bone-patellar tendon-bone (BPTB) is a common autograft and allograft source used for anterior cruciate ligament (ACL) reconstruction. Although the failure rate is generally higher for allografts, donor site morbidity and anterior knee pain can be issues with BPTB autografts. Controversy exists regarding the functional outcomes, complications, and knee stability of these grafts, previous comparisons of which have been based on smaller samples of case series.

PURPOSE

To compare BPTB autografts to allografts for ACL reconstruction, specifically with regard to patient satisfaction, return to preinjury activity level, and postoperative functional outcomes.

STUDY DESIGN

Meta-analysis.

METHODS

A total of 76 studies published between 1998 and 2012, including a total of 5182 patients, were reviewed. It was not required for studies to be comparative in nature. Outcomes evaluated were graft rupture rate, return to preinjury activity level, overall and subjective International Knee Documentation Committee (IKDC), Lysholm, Tegner activity, Cincinnati Knee Rating System, pivot shift, and single-legged hop tests, as well as KT-1000 arthrometer side-to-side difference and presence of anterior knee pain. Summary odds ratios with 95% confidence intervals were calculated to compare BPTB autografts to allografts for each outcome.

RESULTS

Outcomes on subjective IKDC, Lysholm, Tegner, single-legged hop, and KT-1000 arthrometer were statistically significantly in favor of autografts. Return to preinjury activity level, overall IKDC, pivot shift, and anterior knee pain were significantly in favor of allografts, although allograft BPTB demonstrated a 3-fold increase in rerupture rates compared with autograft (12.7% vs 4.3%). There was no significant difference between the 2 groups for Cincinnati Knee scores.

CONCLUSION

Patients undergoing ACL reconstruction with BPTB autografts demonstrate lower rates of graft rupture, lower levels of knee laxity, and improved single-legged hop test results and are more generally satisfied postoperatively compared with patients undergoing reconstruction with allograft BPTB.

Changes in serum biomarkers of cartilage turnover after anterior cruciate ligament injury

BACKGROUND

Biomarkers of cartilage turnover and joint metabolism have a potential use in detecting early degenerative changes after a traumatic knee joint injury; however, no study has analyzed biomarkers before an anterior cruciate ligament (ACL) injury and again after injury or in comparison with a similar group of uninjured controls.

HYPOTHESIS

Changes in serum biomarker levels and the ratio of cartilage degradation to synthesis, from baseline to follow-up, would be significantly different between ACL-injured patients and uninjured controls.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This case-control study was conducted to examine changes in serum biomarkers of cartilage turnover following ACL injury in a young athletic population. Specifically, 2 markers for type II collagen and aggrecan synthesis (CPII and CS846, respectively) and 2 markers of types I and II degradation and type II degradation only (C1,2C and C2C, respectively) were studied. Preinjury baseline serum samples and postinjury follow-up samples were obtained for 45 ACL-injured cases and 45 uninjured controls matched for sex, age, height, and weight.

RESULTS

Results revealed significant decreases in C1,2C (P = .042) and C2C (P = .006) over time in the ACL-injured group when compared with the controls. The change in serum concentrations of CS846 from baseline to follow-up was also significantly different between the ACL-injured patients and uninjured controls (P = .002), as was the change between groups in the ratio of C2C:CPII over time (P = .013). No preinjury differences in the ratio of C1,2C:CPII or C2C:CPII were observed between groups; however, postinjury differences were observed for both ratios.

CONCLUSION

Changes in biomarker concentrations after an ACL injury suggest an alteration in cartilage turnover and joint metabolism in those sustaining ACL injuries compared with uninjured matched controls.