Quadriceps strength and functional capacity after anterior cruciate ligament reconstruction. Patellar tendon autograft versus allograft

Functional performance tests, clinical measurements, and patient-reported outcome measures do not correlate as outcomes 1 year after anterior cruciate ligament reconstruction

PURPOSE

The results after anterior cruciate ligament reconstruction (ACLR) are evaluated by laxity measures, functional tests, and patients' perception by patient-reported outcome measures (PROMs). It is not known, if one of these evaluation instruments is representative or if outcome scores from all must be reported to obtain a full evaluation of the condition. The aim was to study the correlations between these three types of outcomes 1 year after primary ACLR.

METHOD

All adult patients (range 18-45 years) who had an ACLR between 1.1.2019 and 31.12.2021 were offered 1-year follow-up by an independent observer. Preoperative information about knee laxity and peroperative information about the condition of menisci and cartilage were registered. At 1-year follow-up clinical and instrumented knee stability and function assessed by four different hop tests were registered. Patients completed four PROMs (the Subjective International Knee Documentation Committee (IKDC) score, the Knee Numeric-Entity Evaluation Score (KNEES-ACL), the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Lysholm score) and Tegner activity scale and answered anchor questions regarding satisfaction and willingness to repeat the operation.

RESULTS

A total of 190 adults attended the 1-year follow-up and 151 had all assessments. There were only a few positive and weak correlations between performance tests and PROMS and between clinical measurements and PROMS (r = 0.00-0.38), and the majority were of negligible strength. Tegner score had in general the highest correlation (low to moderate). The highest correlation was 0.53 (moderate) between the anchor question about patient satisfaction and Lysholm/IKDC scores. There was no difference in the correlations depending on meniscal condition.

CONCLUSIONS

In ACLR patients there was no clinically relevant correlation between scores obtained by PROMs, a battery of functional performance tests and instrumented laxity of the knee at 1-year follow-up. Therefore, one type of outcome cannot represent the others. This is an argument for always to include and report all three types of outcomes, and conclusions based on one type of outcome may not be sufficient.

LEVEL OF EVIDENCE

II.

Quadriceps Strength After Anterior Cruciate Ligament Reconstruction Compared With Uninjured Matched Controls: A Systematic Review and Meta-analysis

Background:

The limb symmetry index may overestimate the recovery of quadriceps muscle strength after anterior cruciate ligament reconstruction. Comparison of individuals who have had anterior cruciate ligament reconstruction with age-, sex-, and activity-matched individuals might be more appropriate to guide rehabilitation interventions.

Purpose:

To compare the quadriceps strength between the injured limb of people with anterior cruciate ligament reconstruction and the limb of an age-, sex-, and activity-matched control group.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

MEDLINE, CINAHL, EMBASE, SCOPUS, and SPORTDiscus were searched between inception and April 2019. Studies were included if they reported the peak quadriceps strength for persons with anterior cruciate ligament reconstruction and age-, sex-, and activity-matched control groups measured using isometric or isokinetic dynamometry. Risk of bias was assessed, and meta-analyses and metaregression (for effect of time since surgery) were performed.

Results:

A total of 2759 studies were identified and 21 were included for analyses. Quadriceps strength was lower in the limbs with anterior cruciate ligament reconstruction compared with the limb from matched controls within 6 months of anterior cruciate ligament reconstruction (standardized mean difference [SMD], –1.42; 95% CI, –1.62 to –1.23), 6 to 18 months after anterior cruciate ligament reconstruction (SMD, –0.92; 95% CI, –1.18 to –0.66), and >18 to 48 months after anterior cruciate ligament reconstruction (SMD, –0.38; 95% CI, –0.79 to 0.03). Results of the metaregression were significant, with the difference between anterior cruciate ligament reconstruction and matched controls decreasing with time since surgery (P < .001).

Conclusion:

In people with anterior cruciate ligament reconstruction, the injured limb had lower quadriceps strength compared with the limb of age-, sex-, and activity-matched controls up to 4 years after surgery. Clinicians should consider comparison with matched cohorts for return to sports decision making.

A comparison of the effects of plyometric and virtual training on physical and functional performance: a randomized, controlled, clinical trial

BACKGROUND

This study compared the effects of plyometric training (PT) and virtual training (VT) on physical and functional performance.

METHODS

Fifty-five moderately-trained women participated in this randomized, controlled, prospective study. The subjects were randomly assigned to VT (N.=20), PT (N.=18), and control (CG, N.=17) groups. The VT was performed using the Your Body Shape Fitness Evolved 2012^™ exergame in an Xbox360/Kinetic^™ environment. The PT was based on the methods used in previous studies. Both interventions were performed 3 times per week for 8 weeks. Participants in the CG were not submitted to any type of intervention. Physical performance (fitness and athleticism levels) was assessed using the Nike+ Kinetic Training^™ exergame in an Xbox360/Kinetic^™ environment. Functional performance was assessed using the shuttle run (SR), triple hop test (THT), and six-meter timed hop test (STHT).

RESULTS

Postintervention fitness and athleticism levels were significantly greater in VT (P<0.001 and P=0.009) and in PT (P<0.001 and P=0.003) than baselines values. Only VT postintervention fitness level was significantly greater compared to CG (P=0.03). Postintervention SR values were significantly lower than baselines values in all groups (P<0.001). VT (P=0.08) and PT (P=0.006) postintervention values were significantly lower compared to CG. Postintervention THT values were significantly greater than baselines values in VT and PT (P<0.001). VT (P=0.04 - dominant limb) and PT (P=0.003 - dominant limb; and P=0.03 - non-dominant limb) postintervention values were significantly greater compared to CG. Postintervention STHT values were significantly lower than baselines values in VT (P<0.001), PT (P<0.001) and CG (P=0.01-0.02). PT postintervention dominant (P=0.01) and non-dominant (P=0.03) limb values were significantly lower compared to CG.

CONCLUSIONS

Both VT and PT are beneficial for improving physical and functional performance. Therefore, VT might be a new tool that can be used for physical exercise practice and conditioning training in moderately-trained women.

Hop tests can result in higher limb symmetry index values than isokinetic strength and leg press tests in patients following ACL reconstruction

PURPOSE

Quadriceps weakness is a common clinical sign following anterior cruciate ligament injury and reconstruction surgery (ACLR). The aim of this study was to compare strength deficits and the limb symmetry index (LSI) from three different types of functional tests: isokinetic dynamometry, hop test, and leg press.

METHODS

A total of 26 subjects with ACLR (average 8.3 months post-operation) participated in the study. The peak knee extension torque was tested with isokinetic dynamometry at 60/180/300 °/s (ISO60/180/300). Hop distance was tested during single hop (SH) and triple hop (TH). Unilateral peak leg power (POWER) was tested during a bilateral leg press test. LSI was calculated as the ratio of the involved limb over the uninvolved limb values. Pearson correlation coefficients and paired t-tests were used to establish relationships among ISO60/180/300, SH/TH, and POWER values and compare these values between the limbs, respectively. Within-subject one-way analysis of variance (ANOVA) with post hoc analyses was used to compare LSI values among different tests.

RESULTS

ISO60/180/300 values were significantly positively correlated with SH/TH and POWER (P < 0.05), while SH/TH and POWER values were not significantly correlated. Significant limb differences were found in all tests (P = 0.001-0.008). ANOVA revealed significant LSI differences among different tests. Specifically, post hoc analyses revealed that LSI during SH was significantly higher than LSI during ISO60. Similarly, LSI during TH was significantly higher than LSIs from ISO60, ISO180, and POWER tests.

CONCLUSIONS

Peak knee extension torque values were positively associated with hop distance and leg power during the leg press test. However, LSI values should be interpreted with caution as hop tests provided significantly higher LSI values than isokinetic testing. Both isokinetic dynamometry and unilateral leg press machine could be used to isolate and strengthen the quadriceps in the involved limb. The current "gold standard" isokinetic testing at slow speed (ISO60) provided the lowest LSI value among all functional tests; therefore, the current study supported a continued use of isokinetic testing when examining individual's readiness and return-to-sport.

LEVEL OF EVIDENCE

III.

Quadriceps tendon autograft ACL reconstructed subjects overshoot target knee extension angle during active proprioception testing

PURPOSE

To compare the active joint position sense (JPS), muscle strength, and knee functions in individuals who had anterior cruciate ligament (ACL) reconstruction with quadriceps tendon autograft, hamstring tendon autograft, tibialis anterior allograft and healthy individuals. It was hypothesized that when compared to an age and gender-matched healthy control group, subjects who were post-ACL reconstruction would display impaired active joint position sense, knee extensor and flexor strength symmetry and knee function at 1 year post-surgery. A secondary hypothesis was that differences would exist between the quadriceps tendon autograft, hamstring tendon autograft and tibialis anterior allograft groups.

METHODS

Sixty-seven patients with ACL reconstruction and 20 healthy individuals were included. Active JPS reproduction was measured at 15°, 45° and 75° of knee flexion. International Knee Documentation Committee (IKDC) subjective score and one-leg hop test were used to assess the functional status of the patients.

RESULTS

The JPS detection was different at the 15° target angle between groups (F_3.86 = 24.56, p < 0.001). A significantly higher proportion of quadriceps tendon autograft group patients failed to identify the 15° active JPS assessment position compared to the other groups (p < 0.0001). The quadriceps index was lower in patients compared to healthy individuals (p < 0.001), while the hamstring index was similar (n.s.). The knee functional outcomes were similar between ACL reconstructed groups and healthy controls (n.s.).

CONCLUSION

Knee proprioception deficits and impaired muscle strength were evident among patients at a mean 13.5 months post-ACL reconstruction compared with healthy controls. Patients who underwent ACL reconstruction using a quadriceps tendon autograft may be more likely to actively over-estimate knee position near terminal extension. Physiotherapists may need to focus greater attention on terminal knee extension proprioceptive awareness among this patient group.

LEVEL OF EVIDENCE

III.

Clinical Outcomes of Isolated Revision Anterior Cruciate Ligament Reconstruction or in Combination With Anatomic Anterolateral Ligament Reconstruction

BACKGROUND

Although the cause of rotational instability after revision anterior cruciate ligament reconstruction (ACLR) is multifactorial, the rationale of adding an extra-articular procedure is based on its ability to restrict rotational instability.

PURPOSE

To assess the effect of anterolateral ligament (ALL) reconstruction on revision ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 87 patients who underwent revision ACLR between March 2011 and July 2014 with a follow-up of more than 3 years were included in this retrospective study. Patients were divided into the isolated revision ACLR group (group I, n = 45, from March 2011 to January 2013) or the revision ACLR in combination with ALL reconstruction group (group C, n = 42, from February 2013 to July 2014). Subjective knee assessments including the subjective International Knee Documentation Committee (IKDC) form, Lysholm score, Tegner activity scale, and Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale were used. Clinical and functional tests were performed before surgery and at ≥6 months after surgery. All tests were usually completed at 36 months of follow-up.

RESULTS

The mean follow-up duration for groups I and C were 41.5 ± 8.2 and 38.2 ± 6.9 months, respectively ( P = .451). The subjective IKDC score, Tegner score, and ACL-RSI score were significantly better in group C compared with those in group I at the last follow-up (84.3 ± 18.5 vs 75.9 ± 19.2, 7.0 ± 0.8 vs 6.3 ± 0.7, and 69.5 ± 25.4 vs 51.9 ± 23.1, respectively), although they were not significantly different between the 2 groups at 12 months after surgery (79.2 ± 18.8 vs 76.7 ± 17.2, 6.7 ± 0.7 vs 6.5 ± 0.9, and 50.2 ± 24.6 vs 49.9 ± 25.1, respectively). There were no significant differences in KT-2000 arthrometer, isokinetic extensor strength, single-legged hop for distance, co-contraction test, or carioca test results between the 2 groups at the last follow-up ( P = .304, .068, .125, .056, and .066, respectively). Preoperatively, 43 (95.6%) patients in group I and 40 (95.2%) patients in group C had a grade 2 or 3 pivot shift ( P = .387). Postoperatively, 23 (53.5%) patients in group I and 38 (90.5%) patients in group C had a negative pivot shift ( P < .001). Group C showed a higher rate of return to the same level of sports activity than group I (57.1% vs 25.6%, respectively; P = .008), although there was no significant difference in the rate of return to any sports activity at the last follow-up (88.4% in group I vs 88.1% in group C; P = .713).

CONCLUSION

Revision ACLR in combination with ALL reconstruction significantly reduced rotational laxity and showed a higher rate of return to the same level of sports activity than revision ACLR alone, although there were no significant differences in anterior laxity or functional test results between the 2 groups.

Single-leg vertical jump test as a functional test after anterior cruciate ligament reconstruction

BACKGROUND

The aim of this study was to identify the correlations between the single-leg vertical jump (SLVJ) test and subjective and objective tests which were used widely for determining return-to-sports (RTS) after anterior cruciate ligament reconstruction (ACLR).

METHODS

Seventy-five patients (29.5 ± 9.2 years) who underwent ACLR between May 2012 and Jan 2014 were included. Subjective knee scoring systems including subjective International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner activity scale, and ACL-Return to Sports after Injury (ACL-RSI) scale were assessed. Objective tests were also performed.

RESULTS

The limb symmetry index (LSI) for SLVJ test and single-leg hop for distance (SLHD) test was 89.4 ± 14.9% and 90.7 ± 11.7%. LSI for SLVJ test was correlated to subjective IKDC scores (r = 0.26, P = 0.024), Tegner activity scale (r = 0.64, P < 0.001), ACL-RSI scale (r = 0.61, P < 0.001), LSI for SLHD (r = 0.45, P < 0.001), Co-contraction (r = -0.57, P < 0.001), Shuttle run (r = -0.52, P < 0.001), and Carioca (r = -0.54, P < 0.001) tests. In isokinetic strength tests, extensor peak torque (r = 0.30, P = 0.009) and extensor strength deficit (r = -0.41, P < 0.001) were correlated with LSI for SLVJ test.

CONCLUSION

There were considerable correlations between SLVJ test and subjective IKDC scores, Tegner activity scale, ACL-RSI scale, isokinetic extensor muscle strength, and all other functional tests. SLVJ test could be used conveniently to determine RTS after ACLR in outpatient clinics.

LEVEL OF EVIDENCE

Level IV, case series.

A tourniquet-less technique using saline epinephrine irrigation system in an arthroscopic ACL reconstruction in patient with history of popliteal artery ligation

INTRODUCTION

Pneumatic tourniquets use in surgery to create a bloodless surgical field. The majority of orthopaedic surgeon use a tourniquet inflated above systemic blood pressure during arthroscopic anterior cruciate ligament (ACL) reconstruction. A tourniquet use is not free of complications. The disadvantage of tourniquet application include an increased risk of vascular injuries. An arthroscopic ACL reconstruction in patient with history of popliteal artery ligation is challenging. The popliteal artery is the major contributor to the blood supply of the knee joint. This arthroscopic ACL reconstruction does not use tourniquets to preserve the collateral circulation that provides blood supply to the leg and prevent the vascular injuries in patient with history of popliteal artery ligation.

PRESENTATION OF CASE

A-23-year-old female brought to the General Hospital with ACL rupture caused by car accident. The patient had a history of knee dislocation with an open wound and rupture of popliteal artery. The patient underwent open reduction surgery of her right knee joint by orthopaedic surgeon and popliteal artery repair by vascular surgeon. The reduction of the knee joint went good, but the popliteal artery repair was failed and the patient underwent popliteal artery ligation 1 week later. The patient received non-operative treatment for her ACL rupture. After 2 years, she did not get a good improvement to her knee and the patient still felt a giving way sensation and unstability of her knee. Then the patient transferred to the General Hospital for ACL reconstruction, but the surgery required a special consideration in the technique of ACL reconstruction because of the history of popliteal artery ligation.

DISCUSSION

Positioning of the patient for ACL reconstruction The patient supine on an operating table. The leg to undergo surgery has no tourniquet placed because the patient had no popliteal artery and this operation needs to preserve and prevent the vascular ischemia of the collateral artery. Operating room set up with the patient prepped and draped for the diagnostic arthroscopy. It shows a normal cartilage, rupture of the ACL and PCL, rupture of body of the lateral meniscus in the white zone and rupture of body of the medial meniscus in the white zone. To make the bloodless arthroscopic field, cold saline and epinephrine pumped into the knee. Partial meniscectomy of the lateral and medial meniscus was performed. Single bundled ACL reconstruction was performed using hamstring autograft of the contralatelal site with the diameter was 8 mm and fixated by XO button and bioscrew (ConMed). After six months follow up, the patient did not feel giving way, catched, or locking. The patient had a good vascularity of the right lower extremity. There is improvement in Modified Cincinnati Rating System. The pre operative score was 49. The post operative score was 90. Tegner Lysholm Knee Scoring system before surgery was 35 and post operative score was 91. IKDC Scoring before surgery was 21,8 and the score had a good improvement. The IKDC Scoring after surgery was 73,6.

CONCLUSION

ACL reconstruction in patient with popliteal artery ligation is challenging. A tourniquet-less technique using a cold saline and epinephrine solution can be successfully done for pressure controlled into the knee to preserve the collateral arteries flow to the distal limb while still permitting acceptable visual in operative field with good outcome after the surgery.

Comparison of clinical outcomes after anterior cruciate ligament reconstruction with hamstring tendon autograft versus soft-tissue allograft: A meta-analysis of randomised controlled trials

BACKGROUND

Hamstring tendon autografts and soft-tissue allograft are commonly used for anterior cruciate ligament (ACL) reconstruction. However, the clinical outcomes between these two grafts are controversial. This meta-analysis was performed to compare clinical outcomes of primary ACL reconstruction with hamstring tendon autografts versus soft-tissue allografts.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library were searched through 8 September 2017 to identify randomized controlled studies that compared hamstring tendon autografts with soft-tissue allografts for primary ACL reconstruction. Two authors independently graded the methodological quality of each eligible study using the Cochrane Collaboration tool and extracted relevant data. Statistical heterogeneity among the trials was evaluated with chi-square and I-square tests. A sensitivity analysis was conducted to explore sources of heterogeneity. Subgroup analysis was performed to identify potential differences according to type of reconstruction technique (single-bundle or double-bundle).

RESULTS

Eight studies with 785 combined patients (396 hamstring tendon autografts and 389 soft-tissue allografts) were included. Two studies had a high risk of bias. The other six studies had unclear risk of bias. There were significant differences between the groups in subjective International Knee Documentation Committee (IKDC) score (mean difference [MD], 2.43; 95%CI, 0.69-4.18; p = 0.006), Tegner score (MD, 0.24; 95%CI, 0.03-0.45; p = 0.03), and side-to-side difference (MD, -1.37; 95%CI, -2.44 to -0.30; p = 0.01). There was no significant difference between the groups in Lysholm score, complications, pivot shift test, anterior drawer test, Lachman test, overall IKDC score, or range of motion. Subgroup analysis demonstrated that for primary ACL reconstruction using the single-bundle technique, soft-tissue allografts were inferior to hamstring tendon autografts in subjective IKDC score, anterior drawer test, and side-to-side difference.

CONCLUSION

Soft-tissue allografts are inferior to hamstring tendon autografts with respect to subjective patient evaluation and knee stability but superior in the complication of hypoesthesia for patients undergoing primary ACL reconstruction.

Correlation between body mass index and quadrupled hamstring tendon autograft size in ACL reconstruction

PURPOSE

the aim of this study was to assess the relationship of patient weight, height and body mass index (BMI) with the size of the quadrupled hamstring tendon used in anterior cruciate ligament (ACL) reconstruction.

METHODS

from patient records, we retrospectively assessed the weight, height, BMI and graft sizes of 126 patients who underwent ACL reconstruction using a quadrupled hamstring tendon autograft between January 2010 and January 2013 at our institution. The data obtained from perioperative measurements were studied using correlation analysis.

RESULTS

statistically significant relationships were found between patient height and graft diameter (p = 0.033, r = 0.19) and between patient weight and graft diameter (p < 0.0001, r = 0.33). No statistically significant relationships were found between graft diameter and BMI or between graft length and patient height, weight and BMI (p > 0.05).

CONCLUSIONS

patient height and weight were found to be related to quadrupled hamstring graft diameter in our patient population. BMI was not related to the quadrupled hamstring graft size. The exact size of the graft cannot be predicted preoperatively on the basis of these variables.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Diagnostic Accuracy of Handheld Dynamometry and 1-Repetition-Maximum Tests for Identifying Meaningful Quadriceps Strength Asymmetries

Study Design Clinical measurement, cross-sectional. Background Quadriceps deficits are common in individuals with knee joint impairments and impact functional and quality-of-life outcomes. Quadriceps strength symmetry influences clinical decisions after knee injury. Isometric electromechanical dynamometry (ISO-ED) is the gold standard for measuring symmetry, but is not available in all clinical settings. Objectives To compare concurrent validity of handheld dynamometry and 1-repetition-maximum leg press, knee extension from 90° to 0°, and knee extension from 90° to 45° to that of ISO-ED in identifying meaningful quadriceps strength deficits. Methods Fifty-six participants with knee joint impairments completed ISO-ED and 4 alternative measures of quadriceps strength symmetry in a single session. Absolute agreement of alternative measures with ISO-ED was calculated with intraclass correlation coefficients (ICCs). Clinical agreement values at thresholds of 80% and 90% symmetry were compared between the alternatives and ISO-ED. Results Knee extension from 90° to 45° (ICC = 0.67) and handheld dynamometry (ICC = 0.70) had the greatest ICCs. Clinical agreement was also best for these measures for 80% symmetry (κ = 0.56 and 0.55, respectively) and 90% symmetry (κ = 0.19 and 0.33, respectively). Conclusion Handheld dynamometry and 1-repetition-maximum testing of knee extension from 90° to 45° are fair alternatives, although symmetry is typically overestimated. Receiver operating characteristic analysis identified alternative measure thresholds that correlated with the 80% and 90% symmetry thresholds on the ISO-ED. Clinicians should use more stringent symmetry values for these alternative tests to increase the probability that individuals have a minimum ISO-ED symmetry of 80% or 90%. J Orthop Sports Phys Ther 2017;47(2):97-107. doi:10.2519/jospt.2017.6651.

Single-bundle versus double-bundle anterior cruciate ligament reconstruction: A comparative study with propensity score matching

BACKGROUND

Numerous studies have elucidated the functional anatomy and biomechanics of the anterior cruciate ligament (ACL), as a result, double-bundle (DB) ACL reconstruction has received much attention and has become a popular choice because it gives better rotational stability. Many other studies, however, found no differences with respect to stability, and/or other clinical outcomes between the DB and single-bundle (SB) techniques. There is still not enough evidence as to whether the anatomical DB anterior cruciate ligament reconstruction (ACLR) is superior to anatomical SB reconstruction. The purpose of this study is to compare various clinical and functional outcomes between SB and DBACLR at 2 years followup.

MATERIALS AND METHODS

Medical records of patients with ACLR available for at least 2 years followup were reviewed retrospectively. 191 patients (164 males and 25 females) for SB and 48 patients (40 males and 8 females) for DB were selected using the inclusion and exclusion criteria. The mean age of SB and DB was 29.9 and 24.8 years, respectively. Propensity score (PS) was calculated based on age, sex and Tegner activity score and 48 patients in each group were matched by the PS. Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score and Tegneractivity score were investigated. Functional performance tests, isokinetic muscle strength test with Biodex system, pivot shift test and KT-2000 arthrometer test were performed.

RESULTS

At 2 years followup, there were no significant differences between SB and DB group in Lysholm score (92.9 vs. 90.6, P = 0.224), IKDC subjective knee score (88.7 vs. 87.0, P = 0.524), Tegner activity score (7.3 vs. 8.0, P = 0.059). No significant differences were also found in all functional performance tests, isokinetic muscle strength tests in 60° and 180°/s, KT-2000 arthrometer test and pivot shift test (P > 0.05).

CONCLUSIONS

There were no significant differences of clinical and functional outcomes between SB and DB ACLR at 2 years followup.

Autograft versus allograft in anterior cruciate ligament reconstruction: A meta-analysis with trial sequential analysis

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction is considered as the standard surgical procedure for the treatment of ACL tear. However, there is a crucial controversy in terms of whether to use autograft or allograft in ACL reconstruction. The purpose of this meta-analysis is to compare autograft with allograft for patients undergoing ACL reconstruction.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for randomized controlled trials that compared autograft with allograft in ACL reconstruction up to January 31, 2016. The relative risk or mean difference with 95% confidence interval was calculated using either a fixed- or random-effects model. The risk of bias for individual studies according to the Cochrane Handbook. The trial sequential analysis was used to test the robustness of our findings and get more conservative estimates.

RESULTS

Thirteen trials were included, involving 1636 participants. The results of this meta-analysis indicated that autograft brought about lower clinical failure, better overall International Knee Documentation Committee (IKDC) level, better pivot-shift test, better Lachman test, greater Tegner score, and better instrumented laxity test (P < 0.05) than allograft. Autograft was not statistically different from allograft in Lysholm score, subjective IKDC score, and Daniel 1-leg hop test (P > 0.05). Subgroup analyses demonstrated that autograft was superior to irradiated allograft for patients undergoing ACL reconstruction in clinical failure, Lysholm score, pivot-shift test, Lachman test, Tegner score, instrumented laxity test, and subjective IKDC score (P < 0.05). Moreover, there were no significant differences between autograft and nonirradiated allograft.

CONCLUSIONS

Autograft is superior to irradiated allograft for patients undergoing ACL reconstruction concerning knee function and laxity, but there are no significant differences between autograft and nonirradiated allograft. However, our results should be interpreted with caution, because the blinding methods were not well used.

The Utility of Limb Symmetry Indices in Return-to-Sport Assessment in Patients With Bilateral Anterior Cruciate Ligament Reconstruction

BACKGROUND

The incidence of contralateral anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) is high. Often, return-to-sport (RTS) tests of strength and functional hopping rely on limb symmetry indices (LSIs) to identify deficits, although the utility of these measures in athletes with bilateral ACL injuries is unknown.

PURPOSE/HYPOTHESIS

The aim of this study was to investigate if LSIs used as RTS criteria in female patients after unilateral ACLR were appropriate for female patients with bilateral ACL involvement. The hypothesis tested was that asymmetries with traditional LSI measures would be present in a population after unilateral ACLR but would not be present in a population with bilateral ACLR due to the lack of a healthy internal control limb.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 45 female subjects were classified into 3 groups: after second (contralateral) ACLR (ACLR-B; n = 15); after primary unilateral ACLR (ACLR-U; n = 15); and uninjured controls (CTRL; n = 15). After being cleared for RTS, each subject completed a single-legged hop for distance (SLHD), triple hop for distance (THD), and triple-crossover hop for distance (CHD) test, in addition to an isometric quadriceps strength test on both limbs. Means and LSI ([involved limb/uninvolved limb] × 100) were calculated for each test. Limb symmetry deficits were defined by LSI <90%.

RESULTS

Analysis of functional hop testing revealed a side × group interaction for SLHD (P = .001), THD (P = .019), and CHD (P = .04). Side-to-side differences were found in the ACLR-U group for all hop tests (P = .001-.003) and in the ACLR-B group for SLHD (P = .002) and THD tests (P = .024). No side-to side differences were seen in the CTRL group (P > .05). A side × group interaction was found for isometric quadriceps strength (P = .006), with lower LSI seen in the ACLR-U group (81% ± 17.6%) compared with the CTRL group (102.2% ± 10.8%) and the ACLR-B group (95.6% ± 24.9%). Although no interaction was seen, side-to-side differences were noted in the THD in the ACLR-U group (P = .013) and ACLR-B group (P = .024) and in the CHD in the ACLR-U group (P = .001). Despite absence of an LSI deficit, bilateral peak quadriceps strength in the ACLR-B group was comparable to the involved limb of the ACLR-U group and less than in the CTRL group (P = .012).

CONCLUSION

Both the ACLR-U and the ACLR-B groups demonstrated side-to-side deficits during functional hop tests; however, these deficits were not identified according to the clinically accepted LSI values of ≥90%, calling into question the efficacy of current RTS criteria. At the time of RTS, only individuals in the ACLR-U group demonstrated an altered LSI in quadriceps strength. Significantly lower quadriceps strength of both limbs in the ACLR-B group was seen compared with the CTRL group, despite no LSI deficits in quadriceps strength. Current use of LSIs during strength and performance tests may not be an appropriate means of identifying residual deficits in female patients after bilateral ACLR at time of RTS. Furthermore, a better indicator of strength performance in this population may need to include a comparison of strength performance values to the normative values of healthy controls.

Pre-operative quadriceps activation is related to post-operative activation, not strength, in patients post-ACL reconstruction

PURPOSE

Quadriceps activation failure is considered to contribute to the weakness that lingers following anterior cruciate ligament (ACL) reconstruction. Importantly, the impact of pre-operative quadriceps activation on post-operative quadriceps function is unknown. Understanding this relationship is clinically important; as the counteractive approach clinicians should employ pre-operatively to mitigate post-operative quadriceps weakness is unclear. Accordingly, the primary purpose of this study was to investigate the relationship between pre-operative quadriceps activation and post-operative quadriceps strength and activation.

METHODS

Fifty-four individuals post-ACL injury reported for testing on two occasions: prior to surgery and post-surgery once they returned to activity. Quadriceps activation was assessed using the burst superimposition technique and quantified using the central activation ratio. Quadriceps strength was assessed using isometric contractions that were performed at 90° of knee flexion. Multiple linear regressions were utilized to detect the relationships between pre-operative activation and strength and post-operative activation and strength.

RESULTS

Pre-operative activation was not associated with post-operative strength (R(2) = 0.064, P = 0.186). Pre-operative quadriceps activation and strength were associated with post-operative activation (R(2) = 0.383, P ≤ 0.001) and strength (R(2) = 0.465, P ≤ 0.001), respectively.

CONCLUSIONS

Individuals with better pre-operative quadriceps activation demonstrated greater post-operative activation. Similarly, individuals with better pre-operative strength demonstrated better post-operative strength. Pre-operative quadriceps activation was not a predictor of post-operative strength. From a clinical perspective, our work indicates that clinicians should utilize therapies targeting both quadriceps activation and strength prior to ACL reconstruction in order to maximize these factors post-ACL reconstruction, as pre-operative activation and strength are related to post-operative activation and strength, respectively at return-to-activity.

RELIABILITY AND VALIDITY OF A MODIFIED ISOMETRIC DYNAMOMETER IN THE ASSESSMENT OF MUSCULAR PERFORMANCE IN INDIVIDUALS WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Objectives: The aim of this study was to evaluate the reliability and validity of a modified isometric dynamometer (MID) in performance deficits of the knee extensor and flexor muscles in normal individuals and in those with ACL reconstructions. Methods: Sixty male subjects were invited to participate of the study, being divided into three groups with 20 subjects each: control group (GC), group of individuals with ACL reconstruction with patellar tendon graft (GTP, and group of individuals with ACL reconstruction with hamstrings graft (GTF). All individuals performed isometric tests in the MID, muscular strength deficits collected were subsequently compared to the tests performed on the Biodex System 3 operating in the isometric and isokinetic mode at speeds of 60°/s and 180o/s. Intraclass ICC correlation calculations were done in order to assess MID reliability, specificity, sensitivity and Kappa's consistency coefficient calculations, respectively, for assessing the MID's validity in detecting muscular deficits and intra- and intergroup comparisons when performing the four strength tests using the ANOVA method. Results: The modified isometric dynamometer (MID) showed excellent reliability and good validity in the assessment of the performance of the knee extensor and flexor muscles groups. In the comparison between groups, the GTP showed significantly greater deficits as compared to the GTF and GC groups. Conclusion: Isometric dynamometers connected to mechanotherapy equipments could be an alternative option to collect data concerning performance deficits of the extensor and flexor muscles groups of the knee in subjects with ACL reconstruction.

A meta-analysis of anterior cruciate ligament reconstruction with autograft compared with nonirradiated allograft

BACKGROUND

To compare autograft with non-irradiated allograft for reconstruction of anterior cruciate ligament.

METHODS

MEDLINE, EMBASE, and Cochrane Library databases, as well as unpublished and ongoing studies were searched through up to 20 July 2013 to identify studies meeting the pre-stated inclusion criteria.

RESULTS

A total of 12 studies (n=1167, including 597 patients in the autograft group and 570 patients in the allograft group) were included. The methodological scores for randomized controlled trials ranged from two to four (total score: seven), and for non-randomized prospective studies and cohort studies ranged from four to seven (total score: 12). Except for the Lysholm score (WMD, -1.46; P<0.05) showing a statistically significant difference but a small and clinically irrelevant difference, there was no significant difference between autograft and non-irradiated allograft with respect to the overall IKDC (International Knee Documentation Committee) level, subjective IKDC score, Tegner score, complication, ROM (range of motion), Pivot-shift test, Anterior drawer test, Lachman test, Daniel's one-leg hop test, Harner's vertical jump test, and Instrumented knee laxity test. The results were consistent across a series of sensitivity analyses and subgroup analyses.

CONCLUSIONS

Patients with autograft exhibited little clinical advantage over non-irradiated allograft with respect to knee stability, function and side effects. The robustness of the findings might need to be further validated due to the relatively small number of randomized controlled trials.

LEVEL OF EVIDENCE

Level II, meta-analysis of prospective studies.

Deficits in Quadriceps Strength and Patient-Oriented Outcomes at Return to Activity After ACL Reconstruction: A Review of the Current Literature

Context:

Side-to-side quadriceps strength deficits are linked to hazardous lower extremity mechanics and reduced function at a time when individuals are returned to activity after anterior cruciate ligament (ACL) reconstruction. As a result, generalized criteria have emerged in the literature, wherein researchers are recommending that patients be cleared for participation once side-to-side differences in strength are ≤10% of the noninjured limb. Similar recommendations exist for patient-oriented outcomes (ie, self-reported function and hop tests), where deficits of ≤10% are considered ideal at return to activity. It is unclear how many studies actually achieve these clinically recommended results.

Evidence Acquisition:

Articles that reported quadriceps strength deficits as compared to the contralateral limb were collected from peer-reviewed sources available on Medline and Web of Science databases (1990 through August 2014). Search terms included the following: anterior cruciate ligament OR ACL AND muscle weakness, anterior cruciate ligament OR ACL AND strength; return-to-activity AND strength; anterior cruciate ligament OR ACL AND quadriceps.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Average side-to-side strength deficits at 6 months postreconstruction were 23% ± 8% (range, 3%-40%), while the average at 12 months postsurgery was found to be 14% ± 6% (range, 3%-28%). The average deficits in self-reported function at 6 months (mean, 14% ± 5%) and 12 months postsurgery (mean, 13% ± 6%) were also found to be >10%. Performance on hop tests was found to be less than optimal at 6 months postsurgery (mean, 11% ± 7%), but improved at 12 months postsurgery (mean, 1.3% ± 2%).

Conclusion:

This review provides an up-to-date account of the typical deficits in strength and patient-oriented outcomes that exist when formalized physical therapy concludes after ACL reconstruction. Based on the studies included, it seems pertinent that researchers and clinicians continue to investigate interventions capable of improving the recovery of quadriceps strength as well as patient-oriented outcomes as the majority of studies report levels that are well below clinical recommendations.

A Systematic Review of Failed Anterior Cruciate Ligament Reconstruction With Autograft Compared With Allograft in Young Patients

CONTEXT

The advantages of allograft anterior cruciate ligament reconstruction (ACLR), which include shorter surgical time, less postoperative pain, and no donor site morbidity, may be offset by a higher risk of failure. Previous systematic reviews have inconsistently shown a difference in failure prevalence by graft type; however, such reviews have never been stratified for younger or more active patients.

OBJECTIVE

To determine whether there is a different ACLR failure prevalence of autograft compared with allograft in young, active patients.

DATA SOURCES

EMBASE, MEDLINE, Cochrane trials registry.

STUDY SELECTION

Comparative studies of allograft versus autograft primary ACL reconstruction in patients <25 years of age or of high-activity level (military, Marx activity score >12 points, collegiate or semiprofessional athletes).

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Manual extraction of available data from eligible studies. Quantitative synthesis of failure prevalence and Lysholm score (outcomes in ≥3 studies) and I (2) test for heterogeneity. Assessment of study quality using CLEAR NPT and Newcastle-Ottawa Scale (NOS).

RESULTS

Seven studies met inclusion criteria (1 level 1; 2 level 2, 4 level 3), including 788 patients treated with autograft tissue and 228 with various allografts. The mean age across studies was 21.7 years (64% male), and follow-up ranged between 24 and 51 months. The pooled failure prevalence was 9.6% (76/788) for autografts and 25.0% (57/228) for allografts (relative risk, 0.36; 95% CI, 0.24-0.53; P < 0.00001; I (2) = 16%). The number needed to benefit to prevent 1 failure by using autograft was 7 patients (95% CI, 5-10). No difference between hamstrings autograft and patella tendon autograft was noted. Lysholm score was reported in 3 studies and did not differ between autograft and allograft.

CONCLUSION

While systematic reviews comparing allograft and autograft ACLR have been equivocal, this is the first review to examine young and active patients in whom allograft performs poorly.

Functional Performance Testing After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background:

When to allow an athlete to return to unrestricted sporting activity after anterior cruciate ligament (ACL) reconstruction remains controversial.

Purpose:

To report the results of functional performance testing reported in the literature for individuals at differing time points following ACL reconstruction and to examine differences between graft types.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of Medline, Scopus, and Cochrane Central Register of Controlled Trials was performed using PRISMA guidelines. Inclusion criteria were English-language studies that examined any functional rehabilitation test from 6 months to 2 years following ACL reconstruction. All patient-, limb-, and knee-specific demographics were extracted from included investigations. All functional rehabilitation tests were analyzed and compared when applicable.

Results:

The search term returned a total of 890 potential studies, with 88 meeting inclusion and exclusion criteria. A total of 4927 patients were included, of which 66% were male. The mean patient age was 26.5 ± 3.4 years. The predominant graft choices for reconstruction were bone–patellar tendon–bone (BPTB) autograft (59.8%) and hamstring autograft (37.9%). The most commonly reported functional tests were the hop tests. The results of these functional tests, as reported in the Limb Symmetry Index (LSI), improved with increasing time, with nearly all results greater than 90% at 1 year following primary ACL reconstruction. At 6 months postoperatively, a number of isokinetic strength measurements failed to reach 80% LSI, most commonly isokinetic knee extension testing in both BPTB and hamstring autograft groups. The knee flexion strength deficit was significantly less in the BPTB autograft group as compared with those having hamstring autograft at 1 year postoperatively, while no significant differences were found in isokinetic extension strength between the 2 groups.

Conclusion:

Hop testing was the most commonly reported functional test following ACL reconstruction. Increases in performance on functional tests were predictably seen as time increased following surgery. Those with hamstring autografts may experience increased strength deficits with knee flexion versus those having BPTB autograft. These data provide information that may assist providers in determining timing of return to unrestricted sporting activity.

One-stage bilateral anterior cruciate ligament reconstruction

PURPOSE

The ideal treatment for patients presenting with bilateral anterior cruciate ligament (ACL) deficiency remains controversial. The purpose was to evaluate cost and functional results after one-stage bilateral ACL reconstruction using either hamstring or patella tendon autograft.

METHODS

This prospective comparative study was compared the mid-term outcome of 7 patients (14 knees) who had one-stage bilateral ACL reconstruction with that of a matched group of patients who had unilateral reconstruction (21 patients).

RESULTS

The median length of hospital stay was 4 (3-5) nights for the bilateral group and 2 (1-4) nights for the control group. The duration of rehabilitation process in patients from control group with unilateral ACL reconstruction was one week shorter (9 vs 8 weeks). In the bilateral group, the median Lysholm score was 96 (85-100), and in the control group, the median score was 93 (81-100). The median time to return to full-time work and to full sports was 9 weeks and 7 months for the one-stage group and 8 weeks and 6 months for the unilateral group. Six patients (86%) in the bilateral group and 17 patients (81%) in the control group were still performing at their pre-injury level of activity. National Health Institution saved 2925 EUR when we performed one-stage bilateral reconstruction instead of two-stage ACL reconstruction.

CONCLUSIONS

Mid-term clinical results suggested that one-stage bilateral ACL reconstruction using either hamstring or patella tendon autograft is clinically effective. For patients presenting bilateral ACL-deficient knees, one-stage bilateral ACL reconstruction is reproducible, cost effective and does not compromise functional results.

LEVEL OF EVIDENCE

II.

Single-bundle anterior cruciate ligament reconstruction in active young men using bone-tendon achilles allograft versus free tendon achilles allograft

PURPOSE

The purpose was to prospectively compare the outcomes of anterior cruciate ligament (ACL) reconstruction using bone-tendon Achilles allograft with those of free tendon Achilles allograft in 2 groups of active young men.

METHODS

We enrolled 72 subjects in the study. Of these, 33 subjects who had ACL reconstruction with Achilles allograft with calcaneal bone block on its end (group I) and 34 who had ACL reconstruction with free tendon Achilles allograft (group II) were followed up for a minimum of 2 years. The Lachman test, pivot-shift test, and 1-leg hop test were evaluated at the last follow-up. The International Knee Documentation Committee classification, Lysholm score, and side-to-side difference were assessed preoperatively and at the last follow-up. The Tegner activity scale was evaluated before injury and at the last follow-up.

RESULTS

The mean follow-up period was 30.9 months (range, 26 to 38 months). At the last follow-up, there were no statistically significant differences between the 2 groups for the Lachman test, pivot-shift test, 1-leg hop test, International Knee Documentation Committee classification, Lysholm score, and side-to-side difference (P > .05). Three subjects in group I and three in group II showed an activity level 2 steps below the preinjury activity level. The rest of the subjects returned to the preinjury activity level or showed a level 1 step below the preinjury activity level.

CONCLUSIONS

There were no significant differences in clinical outcomes of ACL reconstructions using Achilles allograft between the bone-tendon group and the free tendon group in active young men. Free tendon Achilles allograft may be considered an option for ACL reconstruction.

LEVEL OF EVIDENCE

Level II, therapeutic study, randomized controlled trial.

The impact of quadriceps femoris strength asymmetry on functional performance at return to sport following anterior cruciate ligament reconstruction

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To investigate the impact of quadriceps femoris (QF) muscle strength asymmetry at the time of return to sport on self-reported function and functional performance of individuals following anterior cruciate ligament reconstruction (ACLR).

BACKGROUND

Evidence-based QF strength guidelines for return-to-sport decision making are lacking. Objective guidelines necessitate understanding the impact of QF strength deficits at the time of return to sport on function and performance.

METHODS

Fifty-five individuals (mean age, 17.3 years) who were cleared for return to sport following primary ACLR (ACLR group) and 35 uninjured individuals (mean age, 17.0 years) in a control group participated in the study. QF strength (maximum voluntary isometric contraction) was assessed, and the quadriceps index (QI) was calculated [(involved strength/uninvolved strength) × 100%]. The ACLR group was further subdivided into 2 groups, based on the QI: high quadriceps (QI of 90% or greater) and low quadriceps (QI of less than 85%). The International Knee Documentation Committee Subjective Knee Evaluation Form score was used to assess self-reported function, and hop tests were used to assess functional performance. Multivariate analysis of variance and hierarchical regression analyses were performed.

RESULTS

The individuals in the ACLR group were weaker, reported worse function, and performed worse on hop tests compared to those in the control group (P<.05). The low-quadriceps group demonstrated worse performance on the hop tests compared to the high-quadriceps group and the control group (P ≤.016). Hop test performance did not differ between the high-quadriceps and control groups (P ≥.14). QF strength predicted performance on the hop tests beyond graft type, presence of meniscus injury, knee pain, and knee symptoms.

CONCLUSION

At the time of return to sport, individuals post-ACLR who had weaker QF (QI of less than 85%) demonstrated decreased function, whereas those with minimal QF strength deficits (QI of 90% or greater) demonstrated functional performance similar to uninjured individuals. QF strength deficits predicted hop test performance beyond the influences of graft type, presence of meniscus injury, knee pain, and knee symptoms.

Adequacy of semitendinosus tendon alone for anterior cruciate ligament reconstruction graft and prediction of hamstring graft size by evaluating simple anthropometric parameters

Introduction. Preoperative identification of patients with inadequate hamstring grafts for anterior cruciate ligament reconstruction is still a subject of interest. Purpose. The purpose of this study was to determine whether the semitendinosus tendon length is adequate for four-strand graft harvested by common technique (without bone plug) and whether there is correlation of gracilis and semitendinosus tendon grafts length and diameter of quadrupled graft with anthropometric parameters. Materials and Methods. In this retrospective study, 61 patients (45 males, 16 females) undergoing ACL reconstruction using four-strand hamstring autograft tendons were included. Results. The length of semitendinosus tendon, harvested by the common technique, was in 21% of our cases inadequate in order to be used alone as a four-strand graft especially in females (43%). There was moderate correlation between semitendinosus and gracilis graft diameter and patient's height and weight and fair correlation to BMI. We found no statistically important predictor for graft diameter in female patients. Conclusions. The length of semitendinosus tendon, harvested by common technique, is usually inadequate to be used alone as a four-strand graft especially in females. The most reliable predictor seems to be patient's height in males. In female patients, there is no statistically important predictor.

Validation of functional performance tests after anterior cruciate ligament reconstruction

Purpose

To validate the functional performance tests (FPTs) after anterior cruciate ligament (ACL) reconstruction.

Materials and Methods

Thirty men in their third decade after ACL reconstruction at 6 month follow-up and thirty healthy subjects were selected. Lysholm knee score, International Knee Documentation Committee (IKDC) subjective score, Tegner activity score, KT-2000 arthrometer test, isokinetic strength test, functional performance tests (one leg hop test, co-contraction test, shuttle run test, carioca test) were performed in two groups. We evaluated the test-retest reliability of FPTs in healthy group and the between FPTs and other parameters in ACL reconstruction group.

Results

The test-retest result showed high correlation in co-contraction test (r=0.511), shuttle run test (r=0.746), carioca test (r=0.742). In the ACL reconstruction group, the IKDC score, Tegner activity score, extensor power at 60°/s, and one leg hop test also showed high correlation between each test.

Conclusions

The three FPTs showed correlations with the established methods for determining return to sports activities after ACL reconstruction and had high test-retest reliability. Therefore we believe the three FPTs can be useful methods to assess knee function in athletes after ACL reconstruction.

Relationships among tendon regeneration on MRI, flexor strength, and functional performance after anterior cruciate ligament reconstruction with hamstring autograft

BACKGROUND

There are numerous reports on hamstring tendon regeneration after harvest for anterior cruciate ligament (ACL) reconstruction. However, few studies have evaluated the relationships among the magnetic resonance imaging (MRI) findings of hamstring regeneration, muscle strength, and functional results.

PURPOSE

This study evaluates the correlations among the hamstring regeneration on MRI, flexor strength, and functional performance after hamstring tendon harvesting in ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We enrolled 45 patients who underwent primary ACL reconstruction using hamstring tendon autografts and in whom flexor strength, functional performance, and preoperative and postoperative MRI results were evaluated at least 2 years postoperatively. Isokinetic flexion strength was tested in the standard and prone positions. We evaluated the differences in flexor strength and functional performance according to the number of regenerated tendons. The correlation between the MRI findings (the number of regenerated hamstring tendons and proximal shift of the musculotendinous junction) and the functional performance and flexor strength was analyzed.

RESULTS

The patients were divided into 3 groups according to the regeneration of the hamstring tendons on MRI: both semitendinosus and gracilis tendons regenerated (group SG), only 1 tendon regenerated (group O), and no tendon regenerated (group N). Significant differences were found in the flexor deficit between group N and groups SG and O on the standard and prone position isokinetic tests. There was a significant correlation (ρ = -.472) between the number of regenerated hamstring tendons and the carioca test result. The proximal shift significantly correlated with the flexor deficit in the prone position isokinetic test (semitendinosus, r = .449; gracilis, r = .366).

CONCLUSION

Hamstring tendons regenerated after harvest for ACL reconstruction in a high proportion of the patients. The flexor strength with both the standard and prone position isokinetic tests differed in the 3 groups. The number of regenerated hamstring tendons was significantly correlated with performance on the carioca test. Proximal shifting of the musculotendinous junction was significantly correlated with flexor deficit on the hyperflexion isokinetic test.

Allografts in Anterior Cruciate Ligament Reconstruction

Usual allograft sources for anterior cruciate ligament (ACL) reconstruction are patellar ligament, Achilles tendon, tibialis anterior, and posterior. The advantages of the use of allograft include reduced donor-site morbidity, shorter operative time, smaller incisions, and no size restrictions. The disadvantages include increased cost, slower graft embodiment, and the risk of viral or bacterial infection, which may occur either by transmission from an infected donor or by contamination by the healthcare provider. Careful donor selection, aseptic graft procurement and processing, and tissue sterilization, by irradiation or proprietary chemical processing, are the three major steps of the graft preparation procedure. Successful allograft implantation depends on sterility, reduction of antigenicity, and preservation of the biomechanical properties of the graft. To date, reports on the clinical and functional outcomes of allograft compared to autograft ACL reconstruction are controversial. Overall, graft choice depends on surgeon and patient preference, since no graft can perfectly match the properties of the native ACL.

The effects of hamstring harvesting on outcomes in anterior cruciate ligament-reconstructed patients: a comparative study between hamstring-harvested and -unharvested patients

PURPOSE

The purpose of this study was to evaluate the effects of hamstring harvesting in patients after anterior cruciate ligament (ACL) reconstruction by comparing groups with and without hamstring harvesting.

METHODS

We evaluated the effect of hamstring harvesting in 73 consecutive patients who underwent ACL reconstruction: 39 patients whose hamstrings were harvested for autografts (group H) were compared with 34 patients who received allografts during the same time period (group C [control]). The cases and controls were compared by analyzing the following variables: age, height, weight, mean follow-up period, type of tissue used, and meniscal surgery. Outcomes were assessed by the Lysholm knee score, Tegner activity score, and KT-2000 side-to-side difference (MEDmetric, San Diego, CA), as well as functional performance tests. The flexor deficit and isokinetic peak torque for knee flexion were measured in the sitting position (0° to 90°), and the flexion torque at 90° was measured in the prone position (60° to 120°).

RESULTS

Although significant knee flexion weakness after ACL reconstruction was observed, a significantly greater knee flexor deficit was found in autograft patients than in allograft patients (P < .001). No differences were found between groups in terms of clinical and functional results regardless of hamstring harvesting. The performance of both study groups in all 4 functional tests were significantly correlated with flexor deficit in the sitting position (P < .05) but not in hyperflexion. Significant flexor deficits in both normal and hyperflexed positions were noted in both groups when compared with the unaffected knee (group H, P < .001; group C, P = .002).

CONCLUSIONS

These results indicate significant knee flexion weakness compared with the unaffected knee after ACL reconstruction regardless of hamstring harvesting. Moreover, the greater increase in knee flexor deficit in the hamstring-harvested group compared with the allograft group was statistically significant. However, clinical and functional outcomes were similar between the groups.

LEVEL OF EVIDENCE

Level III, case-control study.

Effect of repeated freezing-thawing on the Achilles tendon of rabbits

The increased use of allograft tissue in the reconstruction of anterior cruciate ligament has brought more focus to the effect of storage and treatment on allograft. The purpose of this study was to observe the effect of histology and biomechanics on Achilles tendon in rabbits through repeated freezing-thawing before allograft tendon transplantation. Rabbit Achilles tendons were harvested and processed according to the manufacture's protocol of tissue bank, and freezing-thawing was repeated three times (group 1) and ten times (group 2). Those received only one cycle were used as controls. Then, tendons in each group were selected randomly to make for histological observations and biomechanics test. Histological observation showed that the following changes happened as the number of freezing-thawing increased: the arrangement of tendon bundles and collagen fibrils became disordered until ruptured, cells disrupted and apparent gaps appeared between tendon bundle because the formation of ice crystals. There were significant differences between the experimental and control groups in the values of maximum load, energy of maximum load and maximum stress, whereas no significant differences existed in other values such as stiffness, maximum strain, elastic modulus, and energy density. Therefore, repeated freezing-thawing had histological and biomechanical effect on Achilles tendon in rabbits before allograft tendon transplantation. This indicates that cautions should be taken in the repeated freezing-thawing preparation of allograft tendons in clinical application.

Allograft compared with autograft infection rates in primary anterior cruciate ligament reconstruction

BACKGROUND

Injuries to the anterior cruciate ligament are the most common surgically treated knee ligament injury. There is no consensus regarding the optimal graft choice between allograft and autograft tissue. Postoperative septic arthritis is an uncommon complication after anterior cruciate ligament reconstruction. The purpose of this study was to compare infection rates between procedures with use of allograft and autograft tissue in primary anterior cruciate ligament reconstruction.

METHODS

A combined prospective and retrospective multicenter cohort study was performed over a three-year period. Graft selection was determined by the individual surgeon. Inclusion and exclusion criteria were equivalent for the two groups (allograft and autograft tissue). Data collected included demographic characteristics, clinical information, and graft details. Patients were followed for a minimum of 5.5 months postoperatively. Our primary outcome was intra-articular infection following anterior cruciate ligament reconstruction.

RESULTS

Of the 1298 patients who had anterior cruciate ligament reconstruction during the study period, 861 met the criteria for inclusion and formed the final study group. Two hundred and twenty-one patients (25.6%) received an autograft, and 640 (74.3%) received an allograft. There were no cases of septic arthritis in either group. The 95% confidence interval was 0% to 0.57% for the allograft group and 0% to 1.66% for the autograft group. The rate of superficial infections in the entire study group was 2.32%. We did not identify a significant difference in the rate of superficial infections between autograft and allograft reconstruction in our study group.

CONCLUSIONS

While the theoretical risk of disease transmission inherent with allograft tissue cannot be eliminated, we found no increased clinical risk of infection with the use of allograft tissue compared with autologous tissue for primary anterior cruciate ligament reconstruction.

Autologous chondrocyte implantation versus microfracture for knee cartilage injury: a prospective randomized trial, with 2-year follow-up

The objective was to evaluate the functional performance over a 2-year period following autologous chondrocyte implantation (ACI) in an open knee procedure compared to microfracture. Objective functional outcome was studied as secondary analysis in a subgroup of patients, in a randomized clinical trial, with concealed allocation and independent evaluators. Sixty-seven patients with local cartilage defect, with a mean size of 2.4 cm(2) (SD 1.5) of the femoral condyle of the knee were included. Thirty-three patients underwent the microfracture and 34 the ACI procedure. An identical rehabilitation protocol was implemented for both groups. Active knee flexion and extension range, anterior laxity, knee extension strength (concentric at 60 degrees/s) and single leg hop performance (single hop, crossover triple hop and 6 m timed hop test) were evaluated pre-surgery and at 6, 9,12 and 24 months post-surgery. We calculated the symmetry index for individual and four performance tests pooled. Mixed linear model analyses were used with confidence interval set at 95%. The change over 2 years for the pooled performance-based tests was comparable between the two treatment arms. At 2 years, 70% (38/54) of all patients returned to >85% symmetry in overall functional performance. A decrease in functional performance at 6 months following ACI resulted in slower recovery at 9 and 12 months compared to microfracture. Rehabilitation following both cartilage repair procedures is a lengthy process. At 2 years after surgery, ACI patients have similar overall functional outcome compared to microfracture patients.

Anterior cruciate ligament-deficient potential copers and noncopers reveal different isokinetic quadriceps strength profiles in the early stage after injury

BACKGROUND

Isokinetic muscle strength testing using the peak torque value is the most frequently included quadriceps muscle strength measurement for anterior cruciate ligament (ACL)-injured subjects. PURPOSE AND HYPOTHESES: The purpose of this study was to investigate quadriceps muscle performance during the whole isokinetic curve in subjects with ACL deficiency classified as potential copers or noncopers and to investigate whether these curve profiles were associated with single-legged hop performance. We hypothesized that quadriceps muscle torque at other knee flexion angles than peak torque would give more information about quadriceps muscle strength deficits. Furthermore, we hypothesized that there would be significant torque differences between potential copers and noncopers and a significant relationship between angle-specific torque values and single-legged hop performance.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Seventy-six individuals with a complete unilateral ACL rupture within the last 3 months were included. The subjects were classified as potential copers and noncopers. Isokinetic quadriceps muscle tests were performed at 60 deg/s. Mean torque values were calculated for peak torque as well as for specific knee flexion angles. The 1-legged hop and the 6-m timed hop tests were included, and symmetry indices were used.

RESULTS

The peak torque value did not identify the largest quadriceps muscle strength deficit. Rather, these were established at knee flexion angles of less than 40 degrees . There were significant differences in angle-specific torque values between potential copers and noncopers (P < .05). Moderate to strong associations were disclosed between angle-specific torque values and single-legged hop performance, but only for noncopers (r > or = .32-.58).

CONCLUSION

Angle-specific quadriceps muscle torque values of less than 40 degrees of knee flexion provide more information on the quadriceps strength deficits after ACL injury than the commonly used peak torque values. Interpretation of the isokinetic curve profiles seems to be of clinical importance for the evaluation of quadriceps muscle performance after ACL injury.

The ability of 4 single-limb hopping tests to detect functional performance deficits in individuals with functional ankle instability

STUDY DESIGN

Experimental laboratory testing using a cross-sectional design.

OBJECTIVES

To determine if functional performance deficits are present in individuals with functional ankle instability (FAI) in 4 single-limb hopping tests, including figure-of-8 hop, side hop, 6-meter crossover hop, and square hop.

BACKGROUND

Conflicting results exist regarding the presence of functional deficits in individuals with FAI. It is important to evaluate whether functional performance deficits are present in this population, as well as if subjective feelings of giving way can assist in identifying these deficits.

METHODS

Sixty college students volunteered for this study. Thirty participants with unilateral ankle instability were placed in the FAI group and 30 participants with no history of ankle injuries were placed in the control group. The FAI group was subsequently further divided to indicate those that reported giving way during the functional test (FAI-GW) and those that did not (FAI-NGW). Time to complete each test was recorded and the mean of 3 trials for each test were used for statistical analysis. To identify performance differences, we used 4 mixed-design 2-way (side-by-group) ANOVAs, 1 for each hop test. A Tukey post hoc test was completed on all significant findings.

RESULTS

We identified a significant side-by-group interaction for all 4 functional performance tests (P<.05). Specifically, for each functional performance test, the FAI limb performed significantly worse than the contralateral uninjured limb in the FAI-GW group. Additionally, the FAI limb in the FAI-GW group performed worse than the FAI limb in the FAI-NGW group, and the matched limb in the control group in 3 of the 4 functional performance tests.

CONCLUSION

We found that functional performance deficits were present in participants with FAI who also experienced instability during the test. This difference was identified when comparing the FAI limb to the contralateral uninjured limb as well as control participants. However, the performance deficits identified in this study were relatively small. Future research in this area is needed to further evaluate the clinical meaningfulness of these findings. Finally, we found that limb dominance did not affect performance.

A systematic review of anterior cruciate ligament reconstruction with autograft compared with allograft

BACKGROUND

Anterior cruciate ligament reconstruction can be performed with use of either autograft or allograft tissue. It is currently unclear if the outcomes of these two methods differ significantly. This systematic review and meta-analysis investigated whether the short-term clinical outcomes of anterior cruciate reconstruction with allograft were significantly different from those with autograft.

METHODS

A computerized search of the electronic databases MEDLINE and EMBASE was conducted. Only therapeutic studies with a prospective or retrospective comparative design were considered for inclusion in the present investigation. Two reviewers independently assessed the methodological quality and extracted relevant data from each included study. If a study failed the qualitative assessment and statistical tests of homogeneity, it was excluded from the meta-analysis. Furthermore, a study was withdrawn from the meta-analysis of a particular outcome if that outcome was not studied or was not reported adequately. A Mantel-Haenszel analysis utilizing a random-effects model allowed for pooling of results according to graft source while accounting for the number of subjects in individual studies.

RESULTS

Nine studies were determined to be appropriate for the systematic review. Eight studies compared bone-patellar tendon-bone grafts, and one study compared quadruple-stranded hamstring grafts. Five studies were prospective comparative studies, and four were retrospective comparative studies. One study, which investigated allografts that underwent a unique sterilization process, demonstrated an allograft failure rate of 45% (thirty-eight of eighty-five). That study failed the qualitative assessment and statistical tests of homogeneity and consequently was excluded from the meta-analysis. When the outcomes from the remaining studies were pooled according to graft source, the meta-analyses of the Lysholm score, instrumented laxity measurements, and the clinical failure rate estimated mean differences and odds ratios that were not significant. These findings were robust during the sensitivity analysis, which varied the included studies or variables on the basis of graft type, instrumented laxity cut-off value, secondary sterilization technique, duration of follow-up, mean patient age, and study methodology.

CONCLUSIONS

In general, the short-term clinical outcomes of anterior cruciate reconstruction with allograft were not significantly different from those with autograft. However, it is important to note that none of these nonrandomized studies stratified outcomes according to age or utilized multivariable modeling to mathematically control for age (or any other possible confounder, such as activity level, that is not equally distributed in the two treatment groups). Understanding these limitations of the best available evidence, the surgeon may incorporate the results of the present systematic review into the informed-consent and shared-decision-making process in order to individualize optimum patient care.

Tissue processing: role of secondary sterilization techniques

Secondary sterilization of musculoskeletal allografts may use chemicals, radiation, or combinations of these. No sterilization techniques have been definitively proven to be more effective than others, and their biomechanical and biological effects on allograft tissue remain largely unknown. The current risk of an allograft infection appears to be much less than the risk of infection surrounding the surgical procedure itself. With appropriate donor screening, improved donor testing—including nucleic acid testing (NAT), and adherence to AATB standards—the risk of disease transmission or infections can be eliminated or substantially decreased.

Rehabilitation after anterior cruciate ligament injury influences joint loading during walking but not hopping

OBJECTIVE

The purpose of this study was to identify changes in clinical outcome and lower extremity biomechanics during walking and hopping in ACL-injured subjects before and after a 20-session neuromuscular and strength training programme.

STUDY DESIGN

Pre and post experimental design.

SETTING

Outpatient clinic, primary care.

PATIENTS

32 subjects with unilateral ACL injury, mean 60 (SD 35) days after injury, with a mean age of 26.2 (5.4) years.

INTERVENTION

The rehabilitation programme consisted of neuromuscular and strength exercises.

MAIN OUTCOME MEASUREMENTS

Outcome measurements assessed before and after a 20-session rehabilitation programme were: self-assessment questionnaires (KOS-ADL, IKDC2000, Global function), four single-leg hop tests, and isokinetic muscle strength tests. Lower extremity kinematics and kinetics were captured during the stance phase of gait and landing after a single leg hop, synchronised with three force plates.

RESULTS

These ACL-injured individuals significantly improved their clinical outcome after rehabilitation. Gait analysis disclosed a significantly improved knee extension moment after rehabilitation, but no change in hip or knee excursions. During landing after hop no change in knee excursion or knee moment was recorded.

CONCLUSION

After rehabilitation the ACL-injured subjects showed a significantly improved clinical outcome, but lower extremity biomechanics were still significantly impaired during both walking and hopping. The rehabilitation programme influenced knee joint loading during walking, but not during hopping. Longer rehabilitation should be considered before ACL-injured individuals return to jumping activities.

FUNCTIONAL PERFORMANCE AND KNEE LAXITY IN NORMAL INDIVIDUALS AND IN INDIVIDUALS SUBMITTED TO ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The aim of this study was to analyze the correlation between deficits in the isokinetic peak torque of the knee extensors and flexors with hop tests, postoperative knee laxity and functional scores in normal and ACL- reconstructed subjects with patellar tendon and hamstring tendon autografts. Methods: Sixty male subjects were enrolled and subdivided into three groups: Twenty subjects without knee injuries (GC group) and two groups of 20 subjects submitted to ACL reconstruction with patellar tendon (GTP group) and hamstrings autograft (GTF group). Results: The results showed significant correlation between knee extensors peak torque and performance in the hop tests for GTF and GC groups. There are no significantly correlations between post op knee laxity and Lysholm score compared with the hop tests and peak torque deficits. Concerning the differences between groups, the GTP group showed greater peak torque deficits in knee extensors, worst Lysholm scores and higher percentage of individuals with lower limb symmetry index (ISM) < 90% in both hop tests when compared to the other two groups. Conclusion: It is not recommendable to use only one measurement instrument for the functional evaluation of ACL-reconstructed patients, because significant correlation between peak torque, subject's functional score, knee laxity and hop tests were not observed in all groups.

[Allografts for cruciate ligament reconstruction]

Allografts have an essential significance in the surgical reconstruction of ligamentous injuries around the knee joint. While in primary anterior cruciate ligament reconstruction allografts are less important than autografts, at least in the European countries, the usage of allografts in anterior cruciate ligament revision surgery is increasing. In addition, allografts represent a good alternative for the reconstruction of the posterior cruciate ligament and the posterolateral structures. Especially in multiligament reconstructions of the knee joint, the usage of allografts may prevent iatrogenic damage of the already traumatized periarticular soft tissue. The present article focuses on the application and clinical results of allografts for ligament reconstruction around the knee joint. Furthermore, the immunological and biological principles of tendon allografts, their availability, processing, and security are discussed.

Functional recovery after anterior cruciate ligament reconstruction: a longitudinal perspective

OBJECTIVE

To evaluate functional hop performance in subjects with an anterior cruciate ligament (ACL) reconstruction with a bone-patellar tendon-bone graft during 12, 18, 26, 39, and 52 weeks.

DESIGN

A longitudinal comparative study.

SETTING

University research laboratory.

PARTICIPANTS

Patients (N=19) were evaluated at 12, 18, 26, 39, and 52 weeks after ACL reconstruction surgery.

INTERVENTION

Testing on 5 separate occasions.

MAIN OUTCOME MEASURES

The Cincinnati Knee Rating System and analog scales, the 6-meter timed hop, crossover hop, stair hop, and vertical hop, and limb symmetry indices.

RESULTS

The uninjured and injured legs and test order were randomized. There was a significant test occasion main effect for both the Cincinnati and analog scores (P=.001). Subjective rating scores improved over the 5 testing occasions. For all 4 hop tests, test occasion and limb main effects were significant (P=.001). Paired t test comparisons at each testing occasion indicated a significant difference between the reconstructed and uninjured limb (P<.05). Furthermore, significant test occasion main effects were noted for limb symmetry indices for the 4 hop tests (P=.001). Using a score of greater than or equal to 85% as a criterion for normative limb symmetry, normative scores were recorded in the 6-m timed hop at the week 18 test occasion, the stair hop and vertical hop at the week 26 test occasion, and the crossover hop at the week 39 test occasion.

CONCLUSIONS

These hop tests showed different levels of imposed demands on the knee that could be used to assess functional recovery and readiness to resume sport.

Isokinetic Dynamometry in Anterior Cruciate Ligament Injury and Reconstruction

The use of isokinetic dynamometry has often been criticised based on the face-validity argument that isokinetic movements poorly resemble the everyday multi-segmented, dynamic activities of human movements. In the anterior cruciate ligament (ACL) reconstruction or deficiency population where muscle deficits are ubiquitous, this review paper has made a case for using isokinetic dynamometry to isolate and quantify these deficits in a safe and controlled manner. More importantly, the usefulness of isokinetic dynamometry, as applied in individuals with ACL reconstruction or deficiency, is attested by its established known-group and convergent validity. Known-group validity is demonstrated by the extent to which a given isokinetic measure is able to identify individuals who could and could not resume pre-morbid athletic or strenuous activities with minimal functional limitations following an ACL injury. Convergent validity is demonstrated by the extent to which a given isokinetic measure closely associates with self-report measures of knee function in individuals with ACL reconstruction. A basic understanding of the measurement properties of isokinetic dynamometry will guide the clinicians in providing reasoned interventions and advancing the clinical care of their clients. Key words: Biomechanics, Knee, Validity

Allograft update: the current status of tissue regulation, procurement, processing, and sterilization

Allografts are commonly used during sports medicine surgical procedures in the United States, and their frequency of use is increasing. Based on surgeon reports, it is estimated that more than 60 000 allografts were used in knee surgeries by members of the American Orthopaedic Society for Sports Medicine in 2005. In the United States, there are governmental agencies and other regulatory bodies involved in the oversight of tissue banks. In 2005, the Food and Drug Administration finalized its requirements for current good tissue practice and has mandated new rules regarding the "manufacture" of allogenic tissue. In response to well-publicized infections associated with the implantation of allograft tissue, some tissue banks have developed methods to sterilize allograft tissue. Although many surgeons have significant concerns about the safety of allografts, the majority believe that sterilized allografts are safe but that the sterilization process negatively affects tissue biology and biomechanics. However, most know very little about the principles of sterilization and the proprietary processes currently used in tissue banking. This article will review the current status of allograft tissue regulation, procurement, processing, and sterilization in the United States.