Hybrid Graft Anterior Cruciate Ligament Reconstruction: A Predictable Graft for Knee Stabilization

Similarities in the kinematics of autografts and hybrid grafts for anterior cruciate ligament reconstruction: Minimum 2 years of follow-up

OBJECTIVE

To compare the clinical results of anterior cruciate ligament reconstruction (ACLR) with autografts and that with hybrid grafts of the same diameter.

METHODS

This study retrospectively included 102 patients who underwent ACLR from August 2017 to July 2019. According to graft type, the patients were divided into an autograft group (58 patients) and a hybrid graft group (44 patients). All grafts were 8.0 mm in diameter. The failure rate, knee kinematics with 6 degrees of freedom (DOFs), signal/noise quotient (SNQ), the Lachman test, pivot-shift test, Lysholm score, Tegner activity score, and International Knee Documentation Committee (IKDC) score were compared in each group after a minimum 2-year follow-up.

RESULTS

There was no significant difference in the failure rate between the autograft group (1.72%) and the hybrid graft group (2.27%) (P > 0.999). The SNQ values of the autograft group (16.42 ± 5.29 and 18.52 ± 5.30) at the middle and proximal sites were lower than those of the hybrid graft group (12.13 ± 5.62 and 16.35 ± 4.64; P = 0.020 and P < 0.001, respectively). In the autograft group, the results of range of motion at 6 DOFs and tibiofemoral kinematics at 5 DOFs (except internal-external rotation) were similar to those of the hybrid graft group (P > 0.05). The Lysholm score, Tegner activity score, IKDC score, Lachman test, and pivot-shift test showed no differences between the two groups (P > 0.05).

CONCLUSIONS

Autograft in ACLR has better graft maturity than hybrid grafts, but their kinematic characteristics are similar.

CLINICAL TRIAL REGISTRATION

ChiCTR2000037869.

Comparison of clinical outcomes between hamstring tendon autografts and hybrid grafts in ACL reconstruction: a systematic review and meta-analysis

BACKGROUND

Hamstring tendon (HT) autografts have become a popular choice for anterior cruciate ligament (ACL) reconstruction. However, small-diameter grafts are inevitably encountered during surgery, which have poor biomechanical properties. Hybrid grafts (HGs) using an allograft combined with small diameter HT are gaining interest from surgeons.

HYPOTHESIS

There would be no difference between the HT autograft and HG in terms of failure, knee stability, and patient-reported outcomes.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

The PubMed, Embase, web of science and Cochrane databases were systematically searched from their inception until July 1, 2022. Clinical trials that compared HG and HT autografts were included. The quality of the included studies was assessed with the Cochrane Collaboration's risk of bias tool and the modified Newcastle-Ottawa Scale. Extracted data were pooled with fixed or random effects depending on the detected heterogeneity.

RESULTS

A total of 14 eligible studies involving 1411 patients (HT: 863; HG: 548) were included in the quantitative meta-analysis. The mean age of the patients involved ranged from 14.6 to 40.4 years. Compared to patients who received HT autografts, patients receiving HGs had similar postoperative failure rate (OR, 0.99; P = 0.97; I2 = 41%), side-to-side difference (MD, -0.16; P = 0.13; I2 = 41%), Subjective IKDC (MD, 0.51; P = 0.58; I2 = 69%), Lysholm (MD, 2.79; P = 0.1; I2 = 79%), Tegner (MD, -0.88; P = 0.56; I2 = 0%). When the available data for failure rate were analyzed by the dose of irradiation, patient age, and mean diameter of the HT, the results of subgroup analyses did not change substantially.

CONCLUSION

This review found no significant differences in failure rates, knee stability, or patient-reported outcomes between autologous HT and HG in ACLR. Surgeons should prioritize autografts of adequate size through optimized techniques and consider hybrid grafts as a last resort, considering the risks associated with allografts.

Comparison of failure rates and functional outcomes between hamstring autografts and hybrid grafts in anterior cruciate ligament reconstruction: A systematic review and meta-analysis

BACKGROUND

The viability of augmenting small-diameter hamstring autografts with allografts remains unclear. Recent studies have reported different clinical results after allograft augmentation. Hence, we sought to determine whether hamstring autografts and hybrid grafts differed in terms of failure rates and functional outcomes after anterior cruciate ligament (ACL) reconstruction. We also evaluated whether the results of the comparisons differed based on allograft sterilization methods.

PATIENTS AND METHODS

This systematic review and meta-analysis were performed by searching the PubMed, Cochrane Library, and EMBASE databases to identify prospective or retrospective studies (evidence levels 1, 2, or 3) that compared the failure rates and functional outcomes of ACL reconstruction using autografts and hybrid grafts.

RESULTS

We identified 15 relevant studies, including 1,521 patients, with 798 and 723 treated using autografts and hybrid grafts, respectively. Fourteen studies were retrospective comparative studies, and one was a prospective randomized controlled trial. Of these, three studies used non-irradiated allografts. In the analysis of all participants, no significant differences in failure rates and subjective International Knee Documentation Committee (IKDC) scores were observed between the autograft and hybrid graft groups. Comparing the autograft and hybrid graft groups that used non-irradiated allografts, no differences in the failure rates and subjective IKDC scores were also noted. Meanwhile, in the groups that used irradiated allograft, the autograft group demonstrated higher Lysholm knee scores and reduced anterior laxity than the hybrid graft group.

DISCUSSION

Overall, ACL reconstruction using hybrid grafts may not reduce failure rates compared to reconstructions using hamstring autografts, although hybrid grafts with irradiation may decrease functional outcomes.

LEVEL OF EVIDENCE

III; systematic review of level II and III studies.

No difference in revision risk between autologous hamstring graft less than 8 mm versus hybrid graft 8 mm or larger in anterior cruciate ligament reconstruction

PURPOSE

Hamstring autograft (HA) is commonly used for primary anterior cruciate ligament reconstruction (ACLR). However, if the harvested HA is inadequate in diameter, it is often augmented with an allograft tendon, forming a hybrid graft (HY). This study sought to evaluate aseptic revision risk following HA versus HY ACLR.

METHODS

A retrospective cohort study was performed using data obtained from our healthcare system's ACLR registry. Patients ≤ 25 years of age who underwent primary isolated ACLR were identified (2005-2020). Graft type and diameter size was the primary exposure of interest: < 8 mm HA and ≥ 8 mm HY. A secondary analysis was performed to examine 7 mm HA and 7.5 mm HA vs ≥ 8 mm HY. Propensity score-weighted Cox proportional hazard regression was used to evaluate the risk of aseptic revision.

RESULTS

The study sample included 1,945 ACLR: 548 ≥ 8 mm HY, 651 7 mm HA, and 672 7.5 mm HA. The crude cumulative aseptic revision probability at 8-years for ≥ 8 mm HY was 9.1%, 11.1% for 7 mm HA, and 11.2% for 7.5 mm HA. In adjusted analysis, no difference in revision risk was observed for < 8 mm HA (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.72-1.82), 7 mm HA (HR 1.23, 95% CI 0.71-2.11), or 7.5 mm HA (HR 1.16, 95% CI 0.74-1.82) compared to ≥ 8 mm HY.

CONCLUSION

In a US-based cohort of ACLR patients aged ≤ 25 years, we failed to observe any differences in aseptic revision risk for HA < 8 mm compared to HY ≥ 8 mm. Augmentation of a HA as small as 7 mm is not necessary to prevent a revision surgery.

LEVEL OF EVIDENCE

Level III.

Comparing Hamstring Autograft With Hybrid Graft for Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To systematically review the literature in an effort to compare the demographics and clinical outcomes of patients undergoing anterior cruciate ligament reconstruction (ACLR) with a hamstring tendon autograft (HT) versus an irradiated or nonirradiated hybrid autograft-allograft.

METHODS

A systematic review of the PubMed, Cochrane Library, and Embase databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All English-language literature that reported general demographics and compared the clinical outcomes of patients undergoing primary ACLR with autograft versus hybrid graft (HG) with a minimum 2-year follow-up was reviewed by 2 independent reviewers. Search terms used were "anterior cruciate ligament" and "hybrid graft." Patients were assessed based on graft failure, anteroposterior laxity, and patient-reported outcomes (Knee Injury and Osteoarthritis Outcome Score, visual analog scale, Subjective International Knee Documentation Committee score, Lysholm, and Tegner scores). Study quality was evaluated with the Modified Coleman Methodology Score and ROBINS-I risk of bias tool.

RESULTS

Twelve studies (1 level II, 11 level III) met inclusion criteria (follow-up, 2.0-8.9 years), including 471 patients undergoing ACLR with an irradiated hybrid graft (IH), 89 patients with a nonirradiated hybrid graft, and 829 patients with HT. Graft diameter ranged from 7.5 to 10.0 mm and from 6.5 to 10.0 mm in HG and HT patients, respectively. Overall, graft failure ranged from 0% to 30.0% and from 0% to 28.3% in HG and HT patients, respectively (I² = 35.9%; 95% confidence interval 0%-74.8%). Among HG patients, graft failure ranged from 0%-30.0% and from 2.4%-4.2% in IH and nonirradiated hybrid graft groups, respectively (I² = 33.6%; 95% confidence interval, 0%-71.8%). Results for postoperative anteroposterior laxity and patient-reported outcomes were also inconsistent.

CONCLUSIONS

Patients undergoing ACLR with HT demonstrate inconsistent differences in clinical outcomes at midterm follow-up compared with IH patients.

LEVEL OF EVIDENCE

III, systematic review of level II and III studies.

Revision Risk of Soft Tissue Allograft Versus Hybrid Graft After Anterior Cruciate Ligament Reconstruction

BACKGROUND

When a harvested hamstring autograft is deemed by the surgeon to be of inadequate diameter, the options include using the small graft, using another autograft from a different site, augmenting with an allograft (hybrid graft), using a different configuration of the graft (eg, 5- or 6-stranded), or abandoning the autograft and using allograft alone. A small graft diameter is associated with a higher revision risk, and using another autograft site includes added harvest-site morbidity; therefore, use of a hybrid graft or an allograft alone may be appealing alternative options. Revision risk for hybrid graft compared with soft tissue allograft is not known.

PURPOSE

To evaluate the risk for aseptic revision surgery after primary anterior cruciate ligament reconstruction (ACLR) using a soft tissue allograft compared with ACLR using a hybrid graft in patients 25 years and younger.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data from a health care system's ACLR registry were used to identify primary isolated unilateral ACLRs between 2009 and 2016 using either a hybrid graft (hamstring autograft with soft tissue allograft) or a soft tissue allograft alone. Multivariable Cox proportional hazards regression was used to evaluate risk for aseptic revision after ACLR according to graft used after adjustment for age, allograft processing, tunnel drilling technique, and region where the primary ACLR was performed.

RESULTS

The cohort included 2080 ACLR procedures; a hybrid graft was used for 479 (23.0%) ACLRs. Median follow-up time was 3.4 years (interquartile range, 1.8-5.1 years). The crude 2-year aseptic revision probability was 5.4% (95% CI, 4.3%-6.7%) for soft tissue allograft ACLR and 3.8% (95% CI, 2.3%-6.4%) for hybrid graft ACLR. After adjustment for covariates, soft tissue allograft ACLR had a higher risk of aseptic revision during follow-up compared with hybrid graft ACLR (hazard ratio, 2.00; 95% CI, 1.21-3.31; P = .007).

CONCLUSION

Soft tissue allografts had a 2-fold higher risk of aseptic revision compared with hybrid graft after ACLR. Future studies evaluating the indications for using hybrid grafts and the optimal hybrid graft diameter is needed.

Magnetic resonance imaging of the quadriceps tendon autograft in anterior cruciate ligament reconstruction

BACKGROUND

Quadriceps tendon (QT) autograft is emerging as a popular technique for primary anterior cruciate ligament (ACL) reconstruction. Studies have shown that it has comparable outcomes to bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts while mitigating post-operative complications associated with these grafts.

PURPOSE

To provide a literature summary of the important pre- and post-operative magnetic resonance imaging (MRI) findings of the quadriceps tendon and pertinent postoperative complications associated with the QT harvest. Radiologists should be familiar with MR findings after autologous graft harvest of the quadriceps tendon for reconstruction of the ACL.

LEVEL OF EVIDENCE

Level IV.

Editorial Commentary: The Trend to Blend: Should We Be Using Hybrid Grafts in Adult Anterior Cruciate Ligament Reconstructions?

Hybrid anterior cruciate ligament grafts augmenting a small-diameter hamstring tendon autograft with nonirradiated allografts can be used with good results in adults. In teens, however, outcomes of hybrid grafts have not been well defined, and other solutions to small hamstring grafts including graft folding, contralateral autograft augmentation, or selection of a different autograft source could be considered.

Hamstring Autograft Versus Hybrid Graft in Anterior Cruciate Ligament Reconstruction: A Systematic Review of Comparative Studies

PURPOSE

To compare (1) patient-reported outcomes, (2) objective knee measures of stability, (3) failures, and (4) reoperations after primary anterior cruciate ligament (ACL) reconstruction with semitendinosus-gracilis autograft versus autograft-allograft hybrid grafts.

METHODS

We performed a systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Multiple databases were searched for studies that compared outcomes of ACL reconstruction with semitendinosus-gracilis autograft versus autograft-allograft hybrid grafts in adult human patients with minimum 2-year follow-up. Knee-specific patient-reported outcome scores, objective knee measures of stability, failures, and reoperations were reported for each study and compared between semitendinosus-gracilis autografts and hybrid grafts. Study heterogeneity and levels of evidence precluded meta-analysis.

RESULTS

We analyzed 6 articles (544 patients; 54.5% male patients; mean age, 30.9 ± 3.9 years; mean follow-up period, 43.6 ± 15.5 months). Of 6 studies, 4 showed no significant differences in International Knee Documentation Committee and Lysholm scores between the semitendinosus-gracilis autograft and hybrid groups. Five of six studies showed no significant differences in KT-1000 measurements between groups. The risk of ACL failure ranged from 3.2% to 8.4% for semitendinosus-gracilis autografts and from 2.4% to 14.3% for hybrid grafts, with no study reporting a significant difference in failure rates between groups. The reoperation rate in the subjects undergoing ACL reconstruction with semitendinosus-gracilis autografts and hybrid grafts ranged from 2.8% to 10.3% and from 2.4% to 48.3%, respectively. In 5 of 6 studies, no significant differences in reoperation rates were found between groups.

CONCLUSIONS

Most studies reported no significant differences in patient-reported outcome scores, objective knee measures of stability, and reoperation rates between semitendinosus-gracilis autografts and hybrid grafts. No significant difference in ACL failure rates was found between groups in any study.

LEVEL OF EVIDENCE

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

Hybrid graft vs autograft in anterior cruciate ligament reconstruction: a meta-analysis

Purpose

We conducted this meta-analysis to evaluate the efficacy of hybrid grafts in anterior cruciate ligament reconstruction (ACLR).

Methods

We performed an electronic search of the Cochrane Library, PubMed, Embase, and ScienceDirect from the inception of these databases to February 2018, based on the terms “anterior cruciate ligament or ACL reconstruction”, “autograft”, “hybrid”, and “augment”. Relevant journals and conference proceedings were searched manually. Quality assessment, data extraction, and calculation of data from the included studies were conducted independently by two reviewers using RevMan 5.1.

Results

One randomized controlled trial and eight nonrandomized controlled trials met inclusion criteria. Larger graft diameters were found in the hybrid-graft group (mean difference −1.47, P=0.0001). There was no significant difference in failure rate (OR 2.13, P=0.21), retearing (OR 2.23, P=0.12), revision of ACLR (OR 1.05, P=0.87) or reoperation (OR 1.27, P=0.35). Subgroup analysis showed that hybrid-graft patients with meniscus injury suffered more revision (OR 4.10, P=0.02) and reoperation (OR 5.74, P=0.001). Both autografts and hybrid grafts performed similarly in most knee-score systems. However, autograft patients had better KT-1000 (mean difference 0.24, P=0.05) and quality-of-life results on the Knee Injury and Osteoarthritis Outcome Score measure (mean difference 7.23, P=0.05).

Conclusion

This meta-analysis of the current literature indicates similar performance of hybrid or autologous grafts in ACLR, though hybrid grafts had larger diameters than autografts. Other potential factors to influence failure, revision, or postoperative knee function, such as irradiation, age at reconstruction, meniscus injury/treatment, and hybrid-graft remodeling, should be investigated further.

Hybrid ACL reconstruction in a 6-year-old female with fibular hemimelia

Fibular hemimelia is a rare congenital malformation that is commonly associated with other lower limb abnormalities. This is a unique case of a bicruciate ligament, anterior cru ciate ligament/posterior cruciate ligament (ACL/PCL) deficiency in a 6-year-old female with fibular hemimelia in which we describe an ACL reconstruction using autograft–allograft hybrid technique. This case focuses on the technical aspects of an ACL reconstruction using a physeal-sparing technique with a hybrid ACL graft in a pediatric patient with fibular hemimelia. When evaluating patients with fibular hemimelia, it is important to consider implications of treatment in a stepwise manner as this condition commonly presents with other abnormalities that will most likely require multiple procedures, including limb lengthening.

Hamstring Autograft Too Small: How Much Allograft Do You Need to Supplement to a Desired Hybrid Graft Size?

PURPOSE

To determine a simple rule for choosing supplemental allograft size for hybrid anterior cruciate ligament reconstruction using mathematical and cadaveric models.

METHODS

Mathematical and cadaveric models were used to determine the rule. The mathematical model required application of the geometric Pythagorean theorem to add areas of circles. Cadaveric semitendinosus and gracilis tendons were combined in multiple quadrupled hamstring size combinations and then sized using standard surgical techniques to confirm the mathematical model.

RESULTS

Geometric measurement, not simple addition, of graft diameters was required to determine the final graft size. Direct comparison of cadaveric and mathematical models showed close relations. If a final graft size of 7 mm is desired, an added diameter of all grafts of approximately 9.5 mm is needed. If a final graft size of 8 mm is desired, an added diameter of all grafts of approximately 11 mm is needed. If a final graft size of 9 mm is desired, an added diameter of all grafts of approximately 12.5 mm is needed. If a final graft size of 10 mm is desired, an added graft diameter of approximately 14 mm is needed. Cadaveric hamstring measurements were similar to the mathematical model.

CONCLUSIONS

By use of mathematical and cadaveric models, simple rules for determining the additional size of allograft diameter needed to supplement undersized hamstring autograft were created.

CLINICAL RELEVANCE

With the increasing availability of allograft types and sizes, surgeons currently have no guidelines on the size of allograft that is required to supplement an undersized hamstring autograft. Simple rules were created for determining the amount of allograft supplementation required for undersized hamstrings and are easily applied to clinical situations.

Editorial Commentary: Built to Last or Just a Trend? Hybrid Graft for Anterior Cruciate Ligament Reconstruction

The use of a hybrid autograft-allograft for primary anterior cruciate ligament reconstruction (ACLR) has gained significant attention in the orthopaedic sports medicine community in recent years. A hybrid graft is most often used to supplement a hamstring autograft with a small diameter, based on evidence that a graft size under a certain diameter (most often 8 mm) increases the risk for graft failure in younger patients. Multiple studies have been published comparing clinical outcomes of ACLR using a hybrid graft versus a hamstring autograft, with conflicting results. Although it is important to attempt to harvest a graft of sufficient size for this procedure, the indications for the use of a hybrid graft for primary ACLR are still unknown.

Graft choice for anatomic anterior cruciate ligament reconstruction: The comparison between thin autograft and thick hybrid graft. An observational study

Great controversy over the graft choice has been lasted now. This study compared the second-look evaluation and clinical outcomes of anatomic anterior cruciate ligament reconstruction (ACL-R) using a thin autograft versus a thick hybrid graft.Seventy-six patients with complete follow-up data were categorized into the autograft group (N = 34) and hybrid group (N = 42). The Lysholm score, Tegner activity level, International Knee Documentation Committee (IKDC) Knee Evaluation Form, and KT-1000 test were performed before and at follow-up. Results were compared, and further comparisons were made for grafts thicker than 8.5 mm.The hybrid graft was thicker than the autograft (9.10 ± 0.52 vs 8.57 ± 0.48 mm, P < .001). The KT-1000 test, subjective evaluation, and activity level scores increased significantly between pre- and postoperation for all patients (P < .001). No significant differences were, however, found between the 2 groups. Only grafts thicker than 8.5 mm were selected from the autograft (N = 14) and hybrid (N = 34) groups, the Lysholm, IKDC, and KT-1000 test scores were significantly superior for the autograft than the hybrid graft (P = .021, P = .005, and P = .024, respectively).For anatomic ACL-R, a pure autograft is superior to a hybrid graft of the same diameter. The purity of the autograft was more important than the size, and augmenting allografts may be unnecessary.

Second-Look Arthroscopic Evaluation and Clinical Outcomes of Anatomic Anterior Cruciate Ligament Reconstruction with Autograft and Hybrid Graft: A Retrospective Study

BACKGROUND Graft choice is very controversial. This study compared the second-look evaluation and clinical outcomes of anatomic ACL-R using a thin autograft versus a thick hybrid graft. MATERIAL AND METHODS Sixty-eight patients who had received ACL-R with hamstring autograft or autograft-allograft hybrid graft accepted second-look arthroscopy were grouped (autograft: n=31, age: 32.8±8.9, Male/Female: 16/15, and hybrid graft: n=37, age: 33.9±8.4, Male/Female: 27/10). Patients were evaluated with the functional score and KT-1000 test before reconstruction. The re-examination and second-look evaluation were performed at 2-year follow-up. Results were compared and further comparisons were made for grafts size >8.5 mm. RESULTS The hybrid group showed thicker graft size and bigger graft occupancy (9.0±0.5 mm vs. 8.5±0.7 mm, P=.003; 80.1±7.0% vs. 69.9±6.9%, P8.5 mm were selected and compared (autograft, n=16; hybrid, n=29). Graft tension and Synovial coverage showed a significant difference (P=.036 and P=.029). The Lysholm, IKDC, and KT-1000 test were significantly superior for the autograft than the hybrid graft (P=.036, P=.004, and P=.003, respectively). CONCLUSIONS A pure autograft is superior to a hybrid graft with same diameter in ACL-R because the augmenting allografts may be null and void. Therefore, a homogenous graft is recommended.

Allograft Augmentation of Hamstring Autograft for Younger Patients Undergoing Anterior Cruciate Ligament Reconstruction

BACKGROUND

Younger patients and those with smaller hamstring autograft diameters have been shown to be at significantly greater risk of graft failure after anterior cruciate ligament (ACL) reconstruction. To date, there is no information in the literature about the clinical success and/or cost-effectiveness of increasing graft diameter by augmenting with semitendinosus allograft tissue for younger patients.

HYPOTHESIS

Hybrid hamstring grafts are a cost-effective treatment option because of a reduced rate of graft failure.

STUDY DESIGN

Cohort study (economic and decision analysis); Level of evidence, 3.

METHODS

We retrospectively identified patients younger than 18 years who had undergone ACL reconstruction by a single surgeon between 2010 and 2015. During this period, the operating surgeon's graft selection algorithm included the use of bone-patellar tendon-bone (BTB) autografts for the majority of patients younger than 18 years. However, hamstring autografts (hamstring) or hybrid hamstring autografts with allograft augment (hybrid) were used in skeletally immature patients and in those whom the surgeon felt might have greater difficulty with postoperative rehabilitation after BTB graft harvest. Patient demographics, graft type, graft diameter, the time the patient was cleared to return to activity, and the need for secondary surgical procedures were compared between the hamstring and hybrid groups. The clinical results were then used to assess the potential cost-effectiveness of hybrid grafts in this select group of young patients with an ACL injury or reconstruction.

RESULTS

This study comprised 88 patients (hamstring group, n = 46; hybrid group, n = 42). The 2 groups did not differ in terms of age, sex, timing of return to activity, or prevalence of skeletally immature patients. Graft diameters were significantly smaller in the hamstring group (7.8 vs 9.9 mm; P < .001), which corresponded with a significantly greater rate of graft failure (13 of 46 [28.3%] vs 5 of 42 [11.9%]; P = .049). As a result of the reduced revision rate, the hybrid graft demonstrated incremental cost savings of US$2765 compared with the hamstring graft, and the hybrid graft was the preferred strategy in 89% of cases.

CONCLUSION

Driven by increased graft diameters and the reduced risk of revision, hybrid grafts appear to be a more cost-effective treatment option in a subset of younger patients with an ACL injury.

Does Allograft Augmentation of Small-Diameter Hamstring Autograft ACL Grafts Reduce the Incidence of Graft Retear?

BACKGROUND

Small-diameter hamstring tendons are frequently encountered during anterior cruciate ligament (ACL) reconstructions in patients with short stature or those who are skeletally immature. The role of augmenting these small-diameter autografts with allograft is unclear.

PURPOSE

To assess clinical outcomes and failure rates in adolescent patients with small hamstring tendon autografts (<7 mm) that were either augmented with soft tissue allograft or accepted "as is" and not augmented.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective chart review of all primary ACL reconstructions performed with hamstring autografts identified 385 patients, of whom 50 (13%) had a quadrupled (semitendinosus-gracilis) graft size less than 7 mm. Patients were grouped based on the surgeon's preference either to augment these grafts with allograft (augmented group; n = 26) or to accept the smaller autograft (nonaugmented group; n = 24). Preoperative demographic, injury, and intraoperative data were documented. All patients were contacted to obtain information about outcome scores, subsequent procedures, and complications. Forty patients (20 in each group) were available for 2-year follow-up.

RESULTS

The mean age of the entire cohort was 15.7 years (range, 12-18 years), and 38% were male. No between-group differences were found with respect to any of the preoperative or intraoperative variables except extremity side. The mean graft size for the augmented group was 8.9 mm and for the nonaugmented group was 6.4 mm. At a mean follow-up of 3 years, 6 (30%) of the patients in the augmented group had a graft failure, whereas only 1 (5%) in the nonaugmented group had a failure ( P = .04). Five of the 6 augmented failures occurred within 1 year of surgery, whereas the single failure in the nonaugmented group occurred 2.7years postoperatively. No differences were noted in the reported outcomes between patients in the augmented and nonaugmented groups who did not experience graft failure (Lysholm score, 88 vs 92; Tegner score, 6.4 vs 6.3; single-assessment numeric evaluation score, 86 vs 86; satisfaction, 8.4 vs 8.9, respectively).

CONCLUSION

Adolescents undergoing an ACL reconstruction frequently have small hamstring tendon autograft size. The augmentation of these small grafts with allograft does not reduce graft failure rates and may in fact lead to higher retear rates, with earlier graft failure.

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.