Preoperative anterior knee laxity did not influence postoperative stability restored by anterior cruciate ligament reconstruction

Validation and Application of a Spanish Version of the ALR-RSI Scale (Ankle Ligament Reconstruction-Return to Sport after Injury) in an Active Non-Athlete Population

The most recent scale to quantify psychological readiness before returning to sport is the ALR-RSI (Ankle Ligament Reconstruction-Return to Sport after Injury) scale. The aim of this study was the cross-cultural adaptation to Spanish and application of the ALR-RSI scale in a sample of active people who were not professional athletes, and to carry out an initial psychometric analysis of the functioning of the instrument in this sample. The sample consisted of 257 participants (161 men and 96 women) aged between 18 and 50 years. The adequacy of the model obtained in the exploratory study was confirmed, obtaining a model composed of one factor and 12 indicators in total. The estimated parameters were statistically significant (p < 0.05), and the factor loadings presented values higher than 0.5; thus, all indicators revealed a satisfactory saturation in the latent variable (convergent validity). Regarding internal consistency, the Cronbach's alpha value was 0.886 (excellent internal consistency). This study demonstrated that the ALR-RSI in Spanish is a valid and reproducible scale for evaluating psychological readiness to return to non-professional physical activity after ankle ligament reconstruction in the Spanish population.

Preoperative quantitative pivot shift does not correlate with in vivo kinematics following ACL reconstruction with or without lateral extraarticular tenodesis

PURPOSE

Quantitative pivot shift (QPS) testing using PIVOT technology can detect high- and low-grade rotatory knee instability following anterior cruciate ligament injury or reconstruction (ACLR). The aim of this project was to determine if preoperative QPS correlates with postoperative knee kinematics in the operative and contralateral, healthy extremity following ACLR with or without lateral extraarticular tenodesis (LET) using a highly precise in vivo analysis system. A positive correlation between preoperative QPS and postoperative tibial translation and rotation following ACLR with or without LET in the operative and healthy, contralateral extremity was hypothesized.

METHODS

Twenty patients with ACL injury and high-grade rotatory knee instability were randomized to undergo anatomic ACLR with or without LET as part of a prospective randomized trial. At 6 and 12 months postoperatively, in vivo kinematic data were collected using dynamic biplanar radiography superimposed with high-resolution computed tomography scans of patients' knees during downhill running. Total anterior-posterior (AP) tibial translation and internal-external tibial rotation were measured during the gait cycle. Spearman's rho was calculated for preoperative QPS and postoperative kinematics.

RESULTS

In the contralateral, healthy extremity, a significant positive correlation was seen between preoperative QPS and total AP tibial translation at 12 months postoperatively (r_s = 0.6, p < 0.05). There were no additional significant correlations observed between preoperative QPS and postoperative knee kinematics at 6 and 12 months postoperatively in the operative and contralateral, healthy extremity for combined isolated ACLR and ACLR with LET patients as well as isolated ACLR patients or ACLR with LET patients analyzed separately.

DISCUSSION

The main finding of this study was that there was a significant positive correlation between preoperative QPS and total AP tibial translation at 12 months postoperatively in the contralateral, healthy extremity. There were no significant correlations between preoperative QPS and postoperative in vivo kinematics at 6 and 12 months following ACLR with or without LET. This suggests that QPS as measured with PIVOT technology does correlate with healthy in vivo knee kinematics, but QPS does not correlate with in vivo kinematics following ACLR with or without LET.

Risk Factors for Abnormal Anteroposterior Knee Laxity After Primary Anterior Cruciate Ligament Reconstruction

PURPOSE

To identify preoperative and intraoperative factors associated with abnormal anterior knee laxity after primary anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 5,462 patients who underwent primary ACL reconstruction at our institution from January 2000 to October 2015, with no associated ligament injuries, were included. Demographic data, information regarding graft used, concomitant meniscal surgery, and instrumented laxity were reviewed. The KT-1000 arthrometer, with an anterior tibial load of 134 N, was used to evaluate knee laxity preoperatively and at 6-month follow-up. Patients were considered to have abnormal anterior knee laxity if the postoperative side-to-side difference was greater than 5 mm (International Knee Documentation Committee laxity grade C or D). A logistic regression analysis was used to evaluate whether patient age, gender, preoperative knee laxity, graft type, and presence of medial or lateral meniscus resection or suture were risk factors for abnormal knee laxity.

RESULTS

The risk of having abnormal anterior knee laxity was significantly related to younger age (<30 years) (odds ratio [OR] 1.44; 95% confidence interval [CI], 1.07-1.95; P = .016), preoperative side-to-side difference greater than 5 mm (OR, 6.57; 95% CI, 4.94-8.73; P < .001), hamstring tendon graft (OR, 1.83; 95% CI, 1.08-3.11; P = .025), and medial meniscus resection (OR, 2.22; 95% CI, 1.61-3.07; P < .001). Female gender (OR, 0.96; 95% CI, 0.72-1.28; P = .80), medial meniscus suture (OR, 0.82; 95% CI 0.42-1.62; P = .58), lateral meniscus resection (OR, 0.73; 95% CI 0.49-1.10; P = .13), and lateral meniscus suture (OR, 0.99; 95% CI, 0.46-2.11; P = .98) were not associated with increased risk of abnormal knee laxity.

CONCLUSIONS

Age less than 30 years, preoperative side-to-side difference greater than 5 mm, hamstring tendon graft, and medial meniscus resection are associated with increased risk of having abnormal anterior knee laxity 6 months after primary ACL reconstruction.

LEVEL OF EVIDENCE

Level III, retrospective comparative trial.

Medio-lateral knee fluency in anterior cruciate ligament-injured athletes during dynamic movement trials

BACKGROUND

Correction of neuromuscular impairments after anterior cruciate ligament injury is vital to successful return to sport. Frontal plane knee control during landing is a common measure of lower-extremity neuromuscular control and asymmetries in neuromuscular control of the knee can predispose injured athletes to additional injury and associated morbidities. Therefore, this study investigated the effects of anterior cruciate ligament injury on knee biomechanics during landing.

METHODS

Two-dimensional frontal plane video of single leg drop, cross over drop, and drop vertical jump dynamic movement trials was analyzed for twenty injured and reconstructed athletes. The position of the knee joint center was tracked in ImageJ software for 500 milliseconds after landing to calculate medio-lateral knee motion velocities and determine normal fluency, the number of times per second knee velocity changed direction. The inverse of this calculation, analytical fluency, was used to associate larger numerical values with fluent movement.

FINDINGS

Analytical fluency was decreased in involved limbs for single leg drop trials (P=0.0018). Importantly, analytical fluency for single leg drop differed compared to cross over drop trials for involved (P<0.001), but not uninvolved limbs (P=0.5029). For involved limbs, analytical fluency values exhibited a stepwise trend in relative magnitudes.

INTERPRETATION

Decreased analytical fluency in involved limbs is consistent with previous studies. Fluency asymmetries observed during single leg drop tasks may be indicative of abhorrent landing strategies in the involved limb. Analytical fluency differences in unilateral tasks for injured limbs may represent neuromuscular impairment as a result of injury.

Clinical outcomes of second-look arthroscopic evaluation after anterior cruciate ligament augmentation

We report the clinical outcome and findings at second-look arthroscopy of 216 patients (mean age 25 years (11 to 58)) who underwent anterior cruciate ligament (ACL) reconstruction or augmentation. There were 73 single-bundle ACL augmentations (44 female, 29 male), 82 double-bundle ACL reconstructions (35 female, 47 male), and 61 single-bundle ACL reconstructions (34 female, 27 male).

In 94 of the 216 patients, proprioceptive function of the knee was evaluated before and 12 months after surgery using the threshold to detect passive motion test.

Second-look arthroscopy showed significantly better synovial coverage of the graft in the augmentation group (good: 60 (82%), fair: 10 (14%), poor: 3 (4%)) than in the other groups (p = 0.039). The mean side-to-side difference measured with a KT-2000 arthrometer was 0.4 mm (-3.3 to 2.9) in the augmentation group, 0.9 mm (-3.2 to 3.5) in the double-bundle group, and 1.3 mm (-2.7 to 3.9) in the single-bundle group: the result differed significantly between the augmentation and single-bundle groups (p = 0 .013). No significant difference in the Lysholm score or pivot-shift test was seen between the three groups (p = 0.09 and 0.65, respectively). In patients with good synovial coverage, three of the four measurements used revealed significant improvement in proprioceptive function (p = 0.177, 0.020, 0.034, and 0.026).

We conclude that ACL augmentation is a reasonable treatment option for patients with favourable ACL remnants.

Cite this article: Bone Joint J 2014;96-B:1325–32

Preoperative patient and injury factors of successful rehabilitation after anterior cruciate ligament reconstruction with single-bundle techniques

PURPOSE

The aim of this systematic review was to determine which patient determinants and injury factors, before anterior cruciate ligament reconstruction by arthroscopic single-bundle techniques, affect postoperative rehabilitation.

METHODS

A search of PubMed, Embase, and the Cochrane Database of Clinical Trials was performed up to February 2013. After application of our inclusion criteria, a final selection was made based on studies' methodologic score assessed with the Newcastle-Ottawa Scale. Meta-analysis was planned for each prognostic factor when data were considered clinically and statistically homogeneous.

RESULTS

Meta-analysis showed that male patients have better functional outcomes. Qualitative synthesis from 18 high-quality studies showed that patients operated on before 30 years of age reach higher activity levels. Patients with high baseline body mass index have lower activity levels after surgery. Smoking results in more symptoms and lower activity levels and subjective scores. Reconstruction before 3 months results in higher activity levels. Preoperatively, a less than 20% quadriceps strength difference, 50° of tibial external rotation or less, absence of flexion deficits, low knee influence on the patient's activity level, and less anterior knee pain result in higher functional scores. Preoperative anterior laxity difference does not predict functional scores. The prognostic value of preoperative activity and competition level for postoperative functional outcome is controversial. Patients with concomitant meniscal injuries have worse functional outcomes. The prognostic value of concomitant chondral pathology for postoperative functional outcome is controversial. Collateral ligament injury could predict functional scores or activity level.

CONCLUSIONS

Male gender, patient age younger than 30 years, reconstruction before 3 months, and high baseline activity level contribute to better functional outcomes. Smoking, high body mass index, quadriceps strength, and range-of-motion deficits affect rehabilitation negatively. Preoperative anterior laxity does not influence rehabilitation. The role of preoperative prognostic injury factors remains unclear because of limited evidence.

LEVEL OF EVIDENCE

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

Do pre-operative knee laxity values influence post-operative ones after anterior cruciate ligament reconstruction?

The objective of this study was to verify whether pre-reconstruction laxity condition effects post-reconstruction outcome. A total of 100 patients who underwent navigated Anterior Cruciate Ligament (ACL) reconstruction were included in the study and knee laxity analysed retrospectively. The knee was assessed in six different laxity tests before and after ACL reconstruction, namely antero-posterior (AP) and internal-external (IE) at 30° and 90°, and varus-valgus (VV) rotations at 0° and 30° of flexion. For each test, the least square (LS) fitting line based on pre-operative-to-post-operative laxity value was calculated. To what degree the post-operative laxity value is explainable by the corresponding pre-operative condition was evaluated by the LS line slope. Post-operatively, for each single patient, the grade of laxity decreased at any evaluated test. The strongest influence of pre-operative-to-post-operative laxity values was found during IE30 and IE90 tests. While AP30 and VV0 tests seem to be those in which the post-reconstruction laxity was barely affected by the pre-surgery condition. The analysis of the global laxity reduction confirms the previous results. Following this hypothesis, our study remarks on the importance of combined lesions to secondary restraints and the importance of fully understanding the residual laxity to optimize the surgical technique.

The relationship of anterior and rotatory laxity between surgical navigation and clinical outcome after ACL reconstruction

PURPOSE

Recently, a computer-assisted navigation system has been used for the quantitative evaluation not only of anterior-posterior (AP) laxity but also rotational laxity of the tibia intraoperatively. The purpose of this study was to investigate how intraoperative AP or rotational laxities measured by the navigation system could correlate with postoperative AP and rotational laxities of the patients.

METHODS

125 patients who underwent primary isolated anatomical single- or double-bundle ACL reconstruction or augmentation using multistranded autologous hamstring tendons were included in the study after a minimum of 2-year follow-up. Clinically, absolute value and side-to-side difference (SSD) of AP translation of the tibia were measured by KT-2000 preoperatively and postoperatively. Intraoperative measurement of AP translation of the tibia and total range of tibial rotation of the ACL-injured knee were carried out using the computer-assisted navigation system. We have investigated the relationship between intraoperative measurements using the navigation system and AP laxity measurements using the KT-2000 knee arthrometer as well as rotational laxity measurements using the manual pivot shift test.

RESULTS

There was a positive correlation between the SSD of preoperative AP translation of the tibia measured by KT-2000 arthrometer and the reduction in AP laxity following ACL reconstruction measured by the navigation system. However, we found no significant correlation between the reduction in AP laxity measured by the navigation system and the SSD of AP translation of the tibia measured by the KT-2000 arthrometer at final follow-up. Postoperatively, eight patients had a positive pivot shift test. Using the navigation system pre- and post-ACL reconstruction, these patients could not be identified by high absolute values for AP laxity nor rotational laxity.

CONCLUSION

Although AP and rotational laxities vary largely among the patients, and AP and rotational stabilization are successfully achieved immediately after ACL reconstruction, intraoperative AP and rotational laxity measured by the navigation system did not influence the postoperative AP and rotational laxities after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Predictors of activity level 2 years after anterior cruciate ligament reconstruction (ACLR): a Multicenter Orthopaedic Outcomes Network (MOON) ACLR cohort study

OBJECTIVE

The study was conducted to quantify activity level 2 years after anterior cruciate ligament reconstruction and identify explanatory variables measured at baseline (demographics, concomitant meniscal/articular cartilage injuries and their treatment) associated with activity level at short-term follow-up (2 years).

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

In 2002, the Multicenter Orthopaedic Outcomes Network (MOON) consortium began enrolling patients undergoing anterior cruciate ligament reconstruction at 6 recruitment sites. The current study reports 2-year follow-up of patients enrolled in 2002. Participants completed a series of validated, patient-oriented questionnaires that included activity level assessment. Measurement of intra-articular pathology, techniques of anterior cruciate ligament reconstruction, and secondary procedures were recorded at baseline by participating surgeons. Multivariable proportional odds ordinal logistic regression was used to assess predictors of activity level after adjusting for baseline patient characteristics. Interquartile range (IQR) odds ratios (ORs) are given for continuous variables. The fitted model that used ORs to specify predicted probabilities of exceeding any activity level was translated into predicted mean activity level.

RESULTS

Of the 446 patients who underwent unilateral anterior cruciate ligament reconstruction, follow-up was obtained on 393 (88%). Male patients comprise 56% of the cohort, with a median age of 23 years. The median and IQR International Knee Documentation Committee subjective score was 53 (range, 40-65) preoperatively and increased to 84 (range, 74-92) 2 years postoperatively. Median and IQR activity level was 12 (range, 8-16) at baseline, and declined to 9 (range, 3-13) at follow-up. The proportion of participants returning to the same or higher level of activity 2 years after anterior cruciate ligament reconstruction was 45%. After controlling for other baseline factors such as age, marital and student status, contralateral knee status, sport and competition level, and articular cartilage/meniscal injuries, factors associated with higher activity levels at 2 years were higher baseline activity (IQROR = 3.84; 95% confidence interval [CI], 1.98-7.43; P < .0001) and lower baseline body mass index (IQROR = 1.37; 95% CI, 1.04-1.82; P = .027). The following baseline factors were associated with lower activity: female sex (OR = 0.60; 95% CI, 0.39-0.91; P = .015), smoking within 6 months prior to surgery (OR = 0.55; 95% CI, 0.33-0.92; P = 0.023), and revision anterior cruciate ligament reconstruction (OR = 0.41; 95% CI, 0.20-0.83; P = .014). Factors presumably related to functional status of the knee such as the condition of the articular cartilage and menisci, as well as normalcy of the contralateral knee, were not predictive of activity level at 2 years.

CONCLUSION

(1) Evaluation of posttreatment activity levels should control for patients' preoperative activity because this is a strong predictor of future activity. (2) Assuming physical activity is an important component of a healthy person, investigation of potential interventions to improve future activity could target modifiable exposures such as weight. (3) Further evaluation is needed to explore the association of sex and revision surgery on activity level following anterior cruciate ligament reconstruction.

A meta-analysis of stability after anterior cruciate ligament reconstruction as a function of hamstring versus patellar tendon graft and fixation type

PURPOSE

Four-strand hamstring graft (4HS) is stronger than 10-mm bone-patellar tendon-bone graft (BPTB) and has equal tunnel pullout strength, but is believed by some to produce lower rates of stability after anterior cruciate ligament reconstruction (ACLR). Our purpose was to test the hypothesis that 4HS ACLR with modern fixation would produce equal or greater stability than BPTB ACLR.

TYPE OF STUDY

Meta-analysis.

METHODS

A computer search was used to find all published reports of ACLR series using HS and/or BPTB. Inclusion criteria were minimum 24-month follow-up, stratified presentation of arthrometric stability data, and at least 30-lb arthrometric testing force. Twenty-four 4HS, 8 2-strand hamstring (2HS), and 32 BPTB series met these criteria and were subdivided into groups according to fixation type. We used the International Knee Documentation Committee classification of a side-to-side instrumented Lachman test difference of < or = 2 mm as normal stability, and > 5 mm difference as abnormal stability. Series with at least 80% normal and at most 3% abnormal stability were designated as high-stability. Meta-analytic methods were used to determine group level differences.

RESULTS

Total 4HS had a higher normal stability rate than total BPTB: 77% versus 66%, P < .001; and lower abnormal stability: 4.4% versus 5.9%, P = .029. The 4HS ACLR using the EndoButton (Smith & Nephew Endoscopy, Andover, MA) and second-generation tibial fixation (EB2-4HS) had higher normal stability (80%) and lower abnormal stability (1.7%) than all other subgroups, including BPTB with 2 interference screws (70% normal, 5.0% abnormal) P < .001; 84% of the series in the EB2-4HS group were high-stability series. No more than 33% of the series from any other group were high-stability.

CONCLUSIONS

The recent literature would suggest that 4HS ACLR produces higher stability rates than BPTB, that 4HS stability rates are fixation dependent, that aperture fixation offers no stability advantage, and that EndoButton with second-generation tibial fixation produces consistently high stability rates.

LEVEL OF EVIDENCE

Level IV.

The effects of semitendinosus and gracilis harvest in anterior cruciate ligament reconstruction

PURPOSE

There is significant debate concerning the morbidity of hamstring harvest for use during anterior cruciate ligament (ACL) reconstruction. We hypothesized that harvest of the semitendinosus and gracilis tendons for ACL reconstruction would result in no measurable hamstring weakness, but that abnormalities of the semitendinosus and gracilis muscle would be observed on magnetic resonance imaging (MRI) scans.

TYPE OF STUDY

Case series.

METHODS

Nine patients undergoing ACL reconstruction with doubled semitendinosus and gracilis tendons had MRI cross-sectional area measurements of both limbs made from axial images and muscle contour was studied on coronal images at 3 and 12 months. The semitendinosus, semimembranosus, gracilis, sartorius, and biceps muscles were evaluated. Isokinetic testing was performed on the operative and nonoperative legs at 60 degrees and 180 degrees per second at 6 and 12 months postoperatively.

RESULTS

The gracilis cross-sectional area at 1 year averaged 2 cm2 on the operative side and 3.7 cm2 on the contralateral side. The semitendinosus averaged 2.1 cm2 on the operative side and 6.6 cm2 on the contralateral side at 1 year. Both of these differences were statistically significant (P < .05). In most cases, the semitendinosus muscle was retracted. Distally, the gracilis and occasionally the semitendinosus were blending with the gastrocnemius or sartorial fascia. The gracilis and semitendinosus in 1 case extended to near the original attachment site. Hamstring strength testing revealed a 26% deficit on the operative side at 60 degrees/second at 6 months and 16% at 180 degrees/second. At 12 months the mean 60 degrees/second deficit was 21% and the deficit at 180 degrees/second was 13%.

CONCLUSIONS

At 1 year, the semitendinosus and gracilis muscles showed significant and persistent atrophy on the operative side and frequent retraction of the semitendinosus muscle belly. There were also hamstring strength deficits persisting at 1 year after the use of the tendons for ACL reconstruction.

LEVEL OF EVIDENCE

Level IV.

Changes in cross-sectional area of hamstring anterior cruciate ligament grafts as a function of time following transplantation

PURPOSE

To measure the cross-sectional area (CSA) of hamstring anterior cruciate ligament (ACL) grafts in humans up to 2 years postoperatively and to estimate the appropriate graft-notch distance (the distance between ACL graft and roof or wall of the notch) at surgery.

TYPE OF STUDY

Case series.

METHODS

Fifty-nine patients, who had consented to have a magnetic resonance imaging (MRI) evaluation postoperatively, underwent endoscopic ACL reconstruction using 3- to 5-strand autogenous hamstring tendons. Intraoperatively, the CSA of the graft was measured using a custom-made area micrometer. Postoperatively, 115 axial MRIs of the grafts (48 at 3 months, 44 at 12 months, and 23 at 24 months) were obtained. They were transmitted to a personal computer and the CSAs of the grafts' midsubstance were calculated. To evaluate the accuracy of the MRI measurement, another 15 patients who consented to have MRI 2 days after surgery were selected and intraoperative graft CSA measurements and graft axial MRI were performed 2 days after surgery.

RESULTS

The CSAs of the grafts measured by MRI 2 days after surgery were well correlated with those directly measured intraoperatively (gamma = 0.905). The CSA of the grafts measured intraoperatively was 43 +/- 5 mm2, and those estimated by MRI at 3, 12, and 24 months were 50 +/- 9 mm2, 54 +/- 9 mm2, and 48 +/- 12 mm2, respectively. The increase in graft diameter at 3, 12, and 24 months was 9% +/- 8%, 13% +/- 10%, and 7% +/- 12%, respectively.

CONCLUSIONS

In humans, the increase in CSA of the ACL graft was smaller compared with previous animal studies. The graft CSA increased up to 29% (13% in diameter) 12 months after surgery. When a 95% confidence interval was used, the percent increase in diameter of the reconstructed graft was estimated to be less than 32% in 95% of the cases. When the graft diameter was 7, 8, or 9 mm, a 1.1-, 1.3-, or 1.4-mm graft-notch distance, respectively, was suitable for impingement-free graft during postoperative periods with 95% of probability.

LEVEL OF EVIDENCE

Level IIII.

Fear of re-injury: a hindrance for returning to sports after anterior cruciate ligament reconstruction

Unrestricted participation in sports activities and return to the pre-injury level is often reported as an indicator of the success of ACL reconstruction. The athletes' choice not to return to their pre-injury level may depend on the knee function, but some times, social reasons or psychological hindrances such as fear of re-injury may influence their return to sports. The aim of this study was to investigate whether fear of re-injury due to movement is of significance for returning to previous level of activity in patients who have undergone anterior cruciate ligament reconstruction. The Tampa Scale of Kinesiophobia (TSK), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and some general questions were mailed to 87 patients who underwent ACL reconstruction 3-4 years before the study was conducted. Sixty-two patients (74%) answered the questionnaires (34 men and 28 women). Fifty-three percent of the patients returned to their pre-injury activity level. The patients who did not return to their pre-injury activity level had more fear of re-injury, which was reflected in the TSK. In addition, high fear of re-injury was correlated with low knee-related quality of life. Fear of re-injury must be considered in the rehabilitation and evaluation of the effects of an ACL reconstruction.

Rehabilitation following anterior cruciate ligament injury: current recommendations for sports participation

Knee ligament injuries often result in a premature end to a career in sports. The treatment after rupture of the anterior cruciate ligament (ACL) may be operative or conservative. In both cases, the goal is to reach the best functional level for the patient without risking new injuries or degenerative changes in the knee. Return to high level of athletic activity has been an indicator of treatment success. Rehabilitation is an important part of the treatment. Knowledge of healing processes and biomechanics in the knee joint after injury and reconstruction, together with physiological aspects on training effects is important for the construction of rehabilitation programmes. Current rehabilitation programmes use immediate training of range of motion. Weight bearing is encouraged within the first week after an ACL reconstruction. Commonly, the patients are allowed to return to light sporting activities such as running at 2-3 months after surgery and to contact sports, including cutting and jumping, after 6 months. In many cases, the decisions are empirically based and the rehabilitation programmes are adjusted to the time selected for returning to sports. In this article, some criteria that should be fulfilled in order to allow the patient to return to sports are presented. Surgery together with completed rehabilitation and sport-specific exercises should result in functional stability of the knee joint. In addition, adequate muscle strength and performance should be used as a critical criterion. Other factors, such as associated injuries and social and psychological hindrances may also influence the return to sports and must be taken into consideration, both during the rehabilitation and at the evaluation of the treatment.

Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with endoButton femoral fixation: A prospective study

PURPOSE

This prospective study was conducted to compare the single-socket and the bi-socket anterior cruciate ligament (ACL) reconstruction techniques in terms of outcome.

TYPE OF STUDY

Nonrandomized control trial.

METHODS

There were 160 consecutive patients with unilateral chronic ACL insufficiency who underwent endoscopic single- or bi-socket ACL reconstruction alternately using multiple-stranded medial hamstring tendon and EndoButton (Smith & Nephew, Andover, MD) femoral fixation. All patients underwent the same postoperative rehabilitation protocol. Of them, 106 patients (57 single, 49 bi) were available for 2-year follow-up.

RESULTS

According to the IKDC Knee Ligament Evaluation Form, 23 patients (40%) of the single-socket group were subjectively graded as normal, 30 (53%) as nearly normal, and 4 (7%) as abnormal. Twenty-six patients (53%) of the bi-socket group were graded as normal, 21 (43%) as nearly normal, and 2 (4%) as abnormal (P =.19). The mean side-to-side anterior laxity difference (KT-1000 manual maximum force) was 0.9 +/- 1.8 mm for the single-socket group and 0.7 +/- 1.2 mm for the bi-socket group (P =.44). Fifty-three of 57 patients (93%) in the single-socket group and all patients in the bi-socket group showed anterior laxity differences of +/-3 mm or less (P =.12). There were no differences in thigh muscle strength between the groups.

CONCLUSIONS

Both single- and bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton fixation provided satisfactory anterior stability, and there were no statistically significant differences in subjective results or measured restored stability between the 2 groups.

The elongation behavior of the anterior cruciate ligament graft in vivo. A long-term follow-up study

The relationship between the elongation values of an autogenous bone-patellar tendon-bone graft immediately after fixation and the anterior-posterior laxity of the knee 5 years later was studied in vivo. Immediately after fixation, the change in the graft midsubstance length during passive knee flexion-extension was measured using a Hall-effect transducer, and anterior-posterior knee laxity was measured with the KT-1000 arthrometer. Subjects were divided into group 1 (N = 6), with graft elongation values bounded by the 95% confidence intervals of the normal anterior cruciate ligament elongation values, and group 2 (N = 7), subjects with values outside these intervals. Immediately after reconstruction, the side-to-side difference in anterior-posterior laxity between the reconstructed and uninjured knees was not different between group 1 (-2.6 +/- 0.7 mm, mean +/- SEM) and group 2 (-1.7 +/- 1.0 mm) (P = 0.49). At 5-year follow-up, the difference was 1.2 +/- 0.7 mm for group 1, while for group 2 it was significantly greater at 4.7 +/- 0.6 mm (P = 0.004). At surgery, graft elongation values produced by flexion of the knee that are outside the limits of the anterior cruciate ligament result in significant increases in anterior knee laxity at long-term follow-up, while grafts with elongation values similar to the normal anterior cruciate ligament do not. Not only is restoration of anterior-posterior laxity values to within normal limits important, but the biomechanical behavior of the graft produced by flexion-extension of the knee should be appreciated.