Knee strength deficits following anterior cruciate ligament reconstruction differ between quadriceps and hamstring tendon autografts

'Real world' clinical implementation of blood flow restriction therapy does not increase quadriceps strength after quadriceps tendon autograft ACL reconstruction

PURPOSE

To retrospectively compare strength outcomes of individuals undergoing postoperative rehabilitation following quadriceps tendon (QT) autograft anterior cruciate ligament reconstruction (ACLR) with and without blood flow restriction therapy.

METHODS

A retrospective review of consecutive patients undergoing ACLR with QT autograft with a minimum of two quantitative postoperative isometric strength assessments via an electromechanical dynamometer (Biodex) was included. Demographics, surgical variables and strength measurement outcomes were compared between patients undergoing blood flow restriction therapy as part of postoperative rehabilitation versus those who did not.

RESULTS

Eighty-one (81) patients met the inclusion criteria. No differences were found in demographic and surgical characteristics between those who received blood flow restriction compared with those who did not. While both groups had improvements in quadriceps peak torque and limb symmetry index (LSI; defined as peak torque of the operative limb divided by the peak torque of the nonoperative limb) over the study period, the blood flow restriction group had significantly lower mean peak torque of the operative limb at first Biodex strength measurement (95.6 vs. 111.2 Nm; p = 0.03). Additionally, the blood flow restriction group had a significantly lower mean LSI than those with no blood flow restriction at the second Biodex measurement timepoint (81% vs. 90%; p = 0.02). No other significant differences were found between the strength outcomes measured.

CONCLUSIONS

Results of this study show that the 'real world' clinical implementation of blood flow restriction therapy to the postoperative rehabilitation protocol following QT autograft ACLR did not result in an increase in absolute or longitudinal changes in quadriceps strength measurements. A better understanding and standardisation of the use of blood flow restriction therapy in the rehabilitation setting is necessary to delineate the true effects of this modality on strength recovery after QT autograft ACLR.

LEVEL OF EVIDENCE

Level III.

Knee flexor strength at 6 months after anterior cruciate ligament reconstruction using hamstring tendon can be predicted from that at 3 months

PURPOSE

This study aimed to identify factors influencing persistent muscle weakness in knee flexor strength after anterior cruciate ligament (ACL) reconstruction using the hamstring tendon and establish a clear cut-off value at 3 months postoperatively for the limb symmetry index (LSI) to exceed 90% at 6 months postoperatively.

METHODS

One hundred forty-eight patients undergoing ACL reconstruction were included and categorised into two groups based on knee flexor strength at 6 months postoperatively: patients with LSI of 90% or greater (achieved group: n = 114) and patients with LSI less than 85% (nonachieved group: n = 34). Items with significant differences between the two groups (preoperative waiting period, LSI to body weight ratio of knee flexor and extensor strength at 3 months postoperatively and peak torque angle of knee flexor muscle) were included in the multiple logistic regression analysis. Additionally, a receiver operating characteristic curve was used to calculate the cut-off value of the LSI at 3 months postoperatively, which was required to achieve the LSI criteria for knee flexor strength 6 months postoperatively.

RESULTS

Multiple logistic regression analysis extracted the preoperative waiting period and LSI for knee flexor strength at 3 months postoperatively. The cut-off value at 3 months postoperatively was 76.9% (area under the curve value, 0.82; sensitivity, 0.76; and specificity, 0.81) of the LSI.

CONCLUSION

The LSI of at least 76.9% for knee flexor strength at 3 months after ACL reconstruction was an indicator for achieving the 6 months postoperatively. This is a criterion to aim for, considering the stress on the graft and the regeneration process of the semitendinosus tendon.

LEVEL OF EVIDENCE

Level III.

Hamstring Tendon Autograft Is Associated With Increased Knee Valgus Moment After Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis

BACKGROUND

There is limited evidence related to the effects of autograft type on functional performance after anterior cruciate ligament reconstruction (ACLR).

PURPOSE/HYPOTHESIS

This study aimed to compare biomechanical outcomes during a drop vertical jump (DVJ) between patients with a hamstring tendon (HT) autograft, quadriceps tendon (QT) autograft with bone block, QT autograft without bone block, and bone-patellar tendon-bone autograft at 6 months postoperatively in an adolescent population. The authors' hypothesized there would be differences in DVJ biomechanics between athletes depending on the type of autograft used.

STUDY DESIGN

Controlled laboratory study.

METHODS

Patients aged 8 to 18 years who underwent primary ACLR were included for analysis. Kinematic and kinetic data collected during a DVJ using a 3-dimensional computerized marker system were assessed at 6 months after ACLR and compared with the uninjured contralateral limb.

RESULTS

A total of 155 participants were included. There were no significant differences in terms of age, sex, or affected leg (P≥ .1973) between groups. The HT group was significantly associated with a larger knee valgus moment at initial contact compared with the QT group (28 × 10-2 vs -35 × 10-2 N·m/kg, respectively; P = .0254) and a significantly larger maximum hip adduction moment compared with the QT with bone block group (30 × 10-2 vs -4 × 10-2 N·m/kg, respectively; P = .0426). Both the QT with bone block (-12 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0265) and QT (-13 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0459) groups demonstrated significantly decreased mean knee extension moments compared with the HT group.

CONCLUSION

The findings of this study suggest that utilizing an HT autograft resulted in a significantly increased knee valgus moment at initial contact compared with a QT autograft without bone block at 6 months after ACLR in adolescent patients performing a DVJ. A QT autograft was found to be associated with significantly decreased extensor mechanism function compared with an HT autograft.

CLINICAL RELEVANCE

This study adds unique kinematic and kinetic information regarding various ACLR autograft options and highlights the biomechanical deficits that should be taken into consideration in rehabilitation.

Musculoskeletal ultrasound imaging of proximal and distal hamstrings cross sectional area in individuals with history of anterior cruciate ligament reconstruction

BACKGROUND

Ultrasound (US) imaging is used by physical therapists for diagnosis and assessment of musculoskeletal injury and follow-up.

PURPOSE

The aim was to identify long-term effects of graft harvesting on hamstrings muscle mass among athletes who had undergone anterior cruciate ligament reconstruction (ACLR).

METHODS

Twenty-eight participants (ages 18-55) were recruited: 18 with history of ACLR using semitendinosus (ST) autograft and 10 healthy controls. Images of the cross-sectional area (CSA) of ST and biceps femoris (BF) were captured at 30% and 70% of the distance from the ischial tuberosity to the popliteal crease. A mixed model ANOVA was used to identify inter-limb differences in the CSA of ST and BF at each location, for each group.

RESULTS

Inter-limb differences were found for the CSA of ST but not BF across both locations for the ACLR group, not controls (p < .001). Within the ACLR group, ST atrophy of the injured limb was relatively greater at the distal vs. proximal location (p < .001).

CONCLUSION

US imaging identified selective atrophy of ST on the injured side with no compensatory hypertrophy of BF. Specific rehabilitation may influence muscle mass of medial vs. lateral hamstrings muscle groups after ACLR using a ST graft, and monitored with US imaging.

A Prospective Randomized Controlled Trial Investigating Quadriceps Versus Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction

BACKGROUND

Numerous graft options are available when undertaking anterior cruciate ligament (ACL) reconstruction (ACLR), although a lack of high-quality evidence exists comparing quadriceps (QT) and hamstring (HT) autografts.

PURPOSE

To investigate patient outcomes in patients undergoing HT versus QT ACLR.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

After recruitment and randomization, 112 patients (HT = 55; QT = 57) underwent ACLR. Patients were assessed pre- and postoperatively (6 weeks and 3, 6, 12, and 24 months), with a range of patient-reported outcome measures (PROMs), graft laxity (KT-1000 arthrometer; primary outcome variable), active knee flexion and extension range of motion (ROM), peak isokinetic knee extensor and flexor strength, and a 6-hop performance battery. Limb symmetry indices (LSIs) were calculated for strength and hop measures. Secondary procedures, ACL retears, and contralateral ACL tears were reported.

RESULTS

All PROMs and knee ROM measures significantly improved (P < .0001), and no other group differences (P > .05) were observed-apart from the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) score, which was significantly better in the HT group at 3 (P = .008), 6 (P = .010), and 12 (P = .014) months. No significant changes were observed in side-to-side laxity from 6 to 24 months (P = .105), and no group differences were observed (P = .487) at 6 (HT mean, 1.2; QT mean, 1.3), 12 (HT mean, 1.1; QT mean, 1.3), and 24 (HT mean, 1.1; QT mean, 1.2) months. While the HT group demonstrated significantly greater (P < .05) quadriceps strength LSIs at 6 and 12 months, the QT group showed significantly greater (P < .05) hamstring strength LSIs at 6, 12, and 24 months. The HT group showed significantly greater (P < .05) LSIs for the single horizontal (6 months), lateral (6 and 12 months), and medial (6 months) hop tests for distance. Up until 24 months, 1 patient (QT at 22 months) had a retear, with 2 contralateral ACL tears (QT at 19 months; HT at 23 months). Secondary procedures included 5 in the HT group (manipulation under anesthesia, notch debridement, meniscal repair, and knee arthroscopy for scar tissue) and 6 in the QT group (notch debridement, meniscal repair, knee arthroscopy for scar tissue, tibial tubercle transfer, and osteochondral autologous transplantation).

CONCLUSION

Apart from the ACL-RSI, the 2 autograft groups compared well for PROMs, knee ROM, and laxity. However, greater hamstring strength LSIs were observed for the QT cohort, with greater quadriceps strength (and hop test) LSIs in the HT cohort. The longer-term review will continue to evaluate return to sports and later-stage reinjury between the 2 graft constructs.

REGISTRATION

ACTRN12618001520224p (Australian New Zealand Clinical Trials Registry).

Comparison of knee flexor strength recovery between semitendinosus alone versus semitendinosus with gracilis autograft for ACL reconstruction: a systematic review and meta-analysis

BACKGROUND

Whether there is a difference in harvesting the semitendinosus tendon alone (S) or in combination with the gracilis tendon (SG) for the recovery of knee flexor strength after anterior cruciate ligament (ACL) reconstruction remains inconclusive. Therefore, this study aimed to assess the recovery of knee flexor strength based on the autograft composition, S or SG autograft at 6, 12, and ≥ 24 months after ACL reconstruction.

METHODS

A systematic review and meta-analysis was conducted following the PRISMA guidelines. A comprehensive search was performed encompassing the Cochrane Library, Embase, Medline, PEDRo and AMED databases from inception to January 2023. Inclusion criteria were human clinical trials published in English, comprised of randomized controlled trials (RCTs), longitudinal cohort-, cross-sectional and case-control studies that compared knee flexor strength recovery between S and SG autografts in patients undergoing primary ACL reconstruction. Isokinetic peak torques were summarized for angular velocities of 60°/s, 180°/s, and across all angular velocities, assessed at 6, 12, and ≥ 24 months after ACL reconstruction. A random-effects model was used with standardized mean differences and 95% confidence intervals. Risk of bias was assessed with the RoBANS for non-randomized studies and the Cochrane RoB 2 tool for RCTs. Certainty of evidence was appraised using the GRADE working group methodology.

RESULTS

Among the 1,227 patients from the 15 included studies, 604 patients received treatment with S autograft (49%), and 623 received SG autograft (51%). Patients treated with S autograft displayed lesser strength deficits at 6 months across all angular velocities d = -0.25, (95% CI -0.40; -0.10, p = 0.001). Beyond 6 months after ACL reconstruction, no significant difference was observed between autograft compositions.

CONCLUSION

The harvest of S autograft for ACL reconstruction yields superior knee flexor strength recovery compared to SG autograft 6 months after ACL reconstruction, irrespective of angular velocity at isokinetic testing. However, the clinical significance of the observed difference in knee flexor strength between autograft compositions at 6 months is questionable, given the very low certainty of evidence and small effect size. There was no significant difference in knee flexor strength recovery between autograft compositions beyond 6 months after ACL reconstruction.

TRIAL REGISTRATION

CRD42022286773.

Strength symmetry after autograft anterior cruciate ligament reconstruction

OBJECTIVE

To compare postoperative isometric quadriceps strength indices (QI%) and hamstring strength limb symmetry indices (HI%) between partial thickness quadriceps tendon (pQT), full thickness quadriceps tendon (fQT), and bone-patellar-tendon bone (BPTB) autograft anterior cruciate ligament reconstruction (ACLR).

METHODS

Patients with primary ACLR with pQT, fQT, or BPTB autograft with the documentation of quantitative postoperative strength assessments between 2016 and 2021 were included. Isometric Biodex data, including QI% and HI% (calculated as the percentage of involved to uninvolved limb strength) were collected between 5 and 8 months and between 9 and 15 months postoperatively.

RESULTS

In total, 124 and 51 patients had 5-8- and 9-15-month follow-up strength data, respectively. No significant difference was detected between groups for sex. However, patients undergoing fQT were found to be older than those undergoing BPTB (24.6±7 vs 20.2±5; ​p = 0.01). There were no significant differences in the number of concomitant meniscus repairs between the groups (pQT vs. fQT vs. BPTB). No significant differences were detected in median (min-max) QI% between pQT, fQT, and BPTB 5-8 months [87 ​% (44%-130 ​%), 84 ​% (44%-110 ​%), 82 ​% (37%-110 ​%) or 9-15 months [89 ​% (50%-110 ​%), 89 ​% (67%-110 ​%), and 90 ​% (74%-140 ​%)] postoperatively. Similarly, no differences were detected in median HI% between the groups 5-8 months or 9-15 months postoperatively.

CONCLUSION

The study was unable to detect differences in the recovery of quadriceps strength between patients undergoing ACLR with pQT, fQT, and BPTB autografts at 5-8 months and 9-15-months postoperatively.

LEVEL OF EVIDENCE

III.

No Association Between Hamstrings-to-Quadriceps Strength Ratio and Second ACL Injuries After Accounting for Prognostic Factors: A Cohort Study of 574 Patients After ACL-Reconstruction

BACKGROUND

The stress on the anterior cruciate ligament (ACL) induced by the quadriceps can be attenuated by activation of the hamstrings by exerting an opposing torque to the anterior translation of tibia. Consequently, considering the ratio between strength of the hamstrings-to-quadriceps (HQ-ratio) may be of value to reduce the odds of second ACL injuries. The objective was therefore to evaluate (1) the association between HQ-ratio and the occurrence of a second ACL injury in patients after ACL-reconstruction within 2 years of return to preinjury sport level and (2) to compare the HQ-ratio between males and females after ACL reconstruction.

METHODS

Patients who had undergone primary ACL reconstruction and participated in knee-strenuous activity preinjury were included. Demographics, the occurrence of a second ACL injury, and muscle strength test results before returning to preinjury sport level were extracted from a rehabilitation registry. The endpoint was set at a second ACL injury or 2 years after return to preinjury sport level. A multivariable logistic regression was used to analyze the association between the HQ-ratio and a second ACL injury.

RESULTS

A total of 574 patients (50.0% female) with a mean age of 24.0 ± 9.4 years at primary ACL reconstruction were included. In the univariable logistic regression analysis, the odds of sustaining a second ACL injury decreased by 3% for every 1% increase in the HQ-ratio (OR 0.97 [95% CI 0.95-1.00], p = 0.025). After adjusting for the time from reconstruction to return to preinjury sport level, sex, preinjury sport level, graft choice, age, and body mass index, the results were no longer significant (OR 0.98 [95% CI 0.95-1.01], p = 0.16). Females had a higher HQ-ratio compared with males for both the ACL-reconstructed and uninjured side (3.7% [95% CI 5.7; 1.8%], p = 0.0002 and 3.3% [95% CI 4.6; 2.1], p < 0.001, respectively).

CONCLUSION

The HQ-ratio did not significantly affect the odds for sustaining a second ACL injury upon return to preinjury sports level after primary ACL reconstruction. Females had a significant higher HQ-ratio than males for both the ACL reconstructed and uninjured side.

Restoring Knee Flexor Strength Symmetry Requires 2 Years After ACL Reconstruction, But Does It Matter for Second ACL Injuries? A Systematic Review and Meta-analysis

BACKGROUND

It is unknown whether knee flexor strength recovers after anterior cruciate ligament (ACL) reconstruction with a hamstring tendon (HT) autograft and whether persistent knee flexor strength asymmetry is associated to a second ACL injury.

OBJECTIVE

We aimed to systematically review (1) whether knee flexor strength recovers after ACL reconstruction with HT autografts, and (2) whether it influences the association with a second ACL injury. A third aim was to summarize the methodology used to assess knee flexor strength.

DESIGN

Systematic review and meta-analysis reported according to PRISMA.

METHODS

A systematic search was performed using the Cochrane Library, Embase, Medline, PEDRo, and AMED databases from inception to December 2021 and until completion in January 2023. Human clinical trials written in English and conducted as randomized controlled trials, longitudinal cohort, cross-sectional, and case-control studies on patients with index ACL reconstructions with HT autografts harvested from the ipsilateral side were considered. Knee flexor strength was measured isokinetically in both the reconstructed and uninjured limb to enable the calculation of the limb symmetry index (LSI). The Risk of Bias Assessment Tool for Non-Randomized Studies was used to assess risk of bias for non-randomized studies and the revised Cochrane Risk of Bias tool was used for randomized controlled trials. For the meta-analysis, the LSI (mean ± standard error) for concentric knee flexor strength at angular velocities of 60°/second (s) and 180°/s preoperatively and at 3 months, 6 months, 12 months, and 24 months were pooled as weighted means with standard errors.

RESULTS

The search yielded 64 studies with a total of 8378 patients, which were included for the assessment of recovery of knee flexor strength LSI, and a total of 610 patients from four studies that investigated the association between knee flexor strength and second ACL injuries. At 1 year after ACL reconstruction, the knee flexor strength LSI had recovered to 89.0% (95% CI 87.3; 90.7%) and 88.3% (95% CI 85.5; 91.1%) for the velocities of 60°/s and 180°/s, respectively. At 2 years, the LSI was 91.7% (95% CI 90.8; 92.6%) and 91.2% (95% CI 88.1; 94.2%), for velocities of 60°/s and 180°/s, respectively. For the association between knee flexor strength and second ACL injuries, there was insufficient and contradictory data.

CONCLUSIONS

There was low to very low certainty of evidence indicating that the recovery of knee flexor strength LSI, defined as ≥ 90% of the uninjured side, takes up to 2 years after ACL reconstruction with HT autografts. Whether knee flexor strength deficits influence the association of second ACL injuries is still uncertain. There was considerable heterogeneity in the methodology used for knee flexor strength assessment, which together with the low to very low certainty of evidence, warrants further caution in the interpretation of our results.

REGISTRATION NUMBER

CRD42022286773.

Suture Augmentation of a Four-Strand Semitendinosus Graft Improves Time-Zero Biomechanical Properties

PURPOSE

To compare the time-zero biomechanical properties of hamstring graft preparations with or without suture augmentation for anterior cruciate ligament reconstruction (ACLR) in a full-construct cadaveric model.

METHODS

Hamstring grafts were harvested from 24 fresh frozen human cadavers and prepared in 1 of 3 ways: quadrupled SemiTendinosus (SemiT), and quadrupled SemiT with suture augmentation (SemiT+2.0-mm tape or SemiT+1.3-mm tape; n = 8 per group). Adjustable loop suspensory implants and cortical buttons were used for fixation on a porcine tibia and acrylic block. Testing included force-controlled cyclic loading at 250 N and 400 N followed by load to failure.

RESULTS

The 2 suture augmentation groups had less total elongation and increased stiffness compared to the nonsuture-augmented group (P = .025). The SemiT+2.0-mm tape group had 36% less total elongation and 34% increased stiffness compared to SemiT+1.3mm tape (P < .001).

CONCLUSIONS

Suture augmentation improves construct biomechanics at time zero following hamstring tendon ACLR. Augmentation with 2.0-mm tape suture improves construct biomechanics compared to 1.3-mm tape suture.

CLINICAL RELEVANCE

Independent suture augmentation of a quadrupled SemiT graft improves ACLR construct biomechanics. Outcomes were improved with augmentation using 2.0-mm tape suture compared to 1.3-mm tape suture.

Weaker Quadriceps Muscle Strength With a Quadriceps Tendon Graft Compared With a Patellar or Hamstring Tendon Graft at 7 Months After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Impaired quadriceps muscle strength after anterior cruciate ligament reconstruction (ACLR) is associated with worse clinical outcomes and a risk of reinjuries. Yet, we know little about quadriceps muscle strength in patients reconstructed with a quadriceps tendon (QT) graft, which is increasing in popularity worldwide.

PURPOSE

To describe and compare isokinetic quadriceps strength in patients undergoing ACLR with a QT, hamstring tendon (HT), or bone-patellar tendon-bone (BPTB) autograft.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We included patients with QT grafts (n = 104) and matched them to patients with HT (n = 104) and BPTB (n = 104) grafts based on age, sex, and associated meniscal surgery. Data were collected through clinical strength testing at a mean of 7 ± 1 months postoperatively. Isokinetic strength was measured at 90 deg/s, and quadriceps strength was expressed as the limb symmetry index (LSI) for peak torque, total work, torque at 30° of knee flexion, and time to peak torque.

RESULTS

Patients with QT grafts had the most impaired isokinetic quadriceps strength, with the LSI ranging between 67.5% and 75.1%, followed by those with BPTB grafts (74.4%-81.5%) and HT grafts (84.0%-89.0%). Patients with QT grafts had a significantly lower LSI for all variables compared with patients with HT grafts (mean difference: peak torque: -17.4% [95% CI, -21.7 to -13.2], P < .001; total work: -15.9% [95% CI, -20.6 to -11.1], P < .001; torque at 30° of knee flexion: -8.8% [95% CI, -14.7 to -2.9], P = .001; time to peak torque: -17.7% [95% CI, -25.8 to -9.6], P < .001). Compared with patients with BPTB grafts, patients with QT grafts had a significantly lower LSI for all variables (mean difference: peak torque: -6.9% [95% CI, -11.2 to -2.7], P < .001; total work: -7.7% [95% CI, -12.4 to -2.9], P < .001; torque at 30° of knee flexion: -6.3% [95% CI, -12.2 to -0.5], P = .03; time to peak torque: -8.8% [95% CI, -16.9 to -0.7], P = .03). None of the graft groups reached a mean LSI of >90% for peak torque (QT: 67.5% [95% CI, 64.8-70.1]; HT: 84.9% [95% CI, 82.4-87.4]; BPTB: 74.4% [95% CI, 72.0-76.9]).

CONCLUSION

At 7 months after ACLR, patients with QT grafts had significantly worse isokinetic quadriceps strength than patients with HT and BPTB grafts. None of the 3 graft groups reached a mean LSI of >90% in quadriceps strength.

Limited preoperative knee extension in anterior cruciate ligament reconstruction using a hamstring tendon affects improvement of postoperative knee extensor strength

PURPOSE

This study aimed to determine the factors affecting knee extensor strength 6 months after anterior cruciate ligament (ACL) reconstruction using autograft hamstring tendon.

METHODS

144 patients who could undergo regular follow-up after ACL reconstruction were divided into 2 groups: those with greater than 90% (Group A: n = 95) and less than 85% (Group B: n = 49) isokinetic knee contraction at 60°/s 6 months post-ACL reconstruction. Basic information, injury status, limited preoperative knee extension, and knee extensor strength at 3 and 6 months postoperatively were compared between the groups. Multivariate logistic analysis was performed and included variables that showed statistically significant differences between the groups in the univariate analysis. In addition, the cut-off value for the limb symmetry index (LSI) at 3 months postoperatively needed to exceed an LSI of 90% at 6 months postoperatively was calculated using the receiver operating characteristics curve.

RESULTS

Age, preoperative waiting period, limited preoperative knee extension, and knee extensor strength at 3 months postoperatively were significantly different between the two groups. The multivariate logistic analysis showed that all the variables affected the improvement in knee extensor strength at 6 months postoperatively. Limited preoperative knee extension was the most significant factor (odds ratio: 15.1, 95% confidence interval: 2.57-118.56, p < 0.01). The LSI cut-off value at 3 months postoperatively was 72.0%.

CONCLUSION

Key factors in achieving the necessary knee extensor strength criteria for return to sports at 6 months post-ACL reconstruction include addressing limited preoperative knee extension and achieving an LSI ≥ 72% in knee extensor strength at 3 months postoperatively.

LEVEL OF EVIDENCE

Level III.

Quadriceps tendon autograft has similar clinical outcomes when compared to hamstring tendon and bone-patellar tendon-bone autografts for revision ACL reconstruction: a systematic review and meta-analysis

PURPOSE

Research regarding revision anterior cruciate ligament reconstruction (RACLR) with quadriceps tendon (QT) autografts is lacking. The purpose of this study was to perform a systematic review and meta-analysis of RACLR with QT and compare its patient outcomes to RACLR with hamstring tendon (HT) and bone-patellar tendon-bone (BTB) autografts.

METHODS

Adhering to PRISMA guidelines, a search for studies using QT in RACLR was performed within PubMed, Scopus, and CINAHL from database date of inception through December 26, 2022. Primary outcomes sought included: failure rate, Lysholm scores, International Knee Documentation Committee (IKDC) scores, IKDC grades, arthrometric knee side-to-side differences (STSD), pivot shift grade, donor site morbidity, return to sport, visual analog scale (VAS) pain scores.

RESULTS

Nine studies were included consisting of 606 RACLR: 349 QT, 169 HT, and 88 BTB. Overall failure rates were 7.6% QT, 13.3% HT, and 8.7% BTB. Mean weighted Lysholm scores were 85.8 ± 3.8 QT, 82.5 ± 3.8 HT and 86.6 ± 4.5 BTB. IKDC average scores were 82.3 ± 1.6 QT, 80.1 ± 1.7 HT, and 81.7 ± 5.5BTB. Combined rates of IKDC A/B grades were 88.4% and 80.0% for QT and HT, respectively. VAS average scores were 0.9 ± 1.1 QT, 1.4 ± 0.2 HT, and 0.7 ± 0.8 for BTB. Side-to-side difference was reported for QT and HT with average values of 1.7 ± 0.6 mm and 2.1 ± 0.5 mm, respectively. Grade 0 or 1 pivot shifts were reported in 96.2% of QT patients and 91.3% of HT. Donor site morbidity, only reported for QT and HT, was 14.6 ± 9.7% and 23.6 ± 14.1%, respectively. QT resulted in a mean Tegner score of 5.9 ± 1.5 versus HT 5.7 ± 1.5. Rate of return to pivoting sports was 38.0% QT, 48.6% HT, and 76.9% BTB. Across all outcomes, there was no significant difference when comparing QT to HT, QT to BTB, and QT compared to HT and BTB combined.

CONCLUSIONS

RACLR with QT yields satisfactory patient reported outcomes, satisfactory improvement in knee laxity, expected return to sport rates, and has an overall 7.6% failure rate. Outcomes are comparative to those of HT and BTB making it an acceptable graft choice for RACLR. Surgeons should consider using QT autograft for RACLR, especially when other autografts are unavailable.

LEVEL OF EVIDENCE

IV.

Graft-Specific Surgical and Rehabilitation Considerations for Anterior Cruciate Ligament Reconstruction with the Quadriceps Tendon Autograft

Anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone (BPTB) or hamstring tendon (HT) autograft has traditionally been the preferred surgical treatment for patients returning to Level 1 sports. More recently, international utilization of the quadriceps tendon (QT) autograft for primary and revision ACLR has increased in popularity. Recent literature suggests that ACLR with the QT may yield less donor site morbidity than the BPTB and better patient-reported outcomes than the HT. Additionally, anatomic and biomechanical studies have highlighted the robust properties of the QT itself, with superior levels of collagen density, length, size, and load-to-failure strength compared to the BPTB. Although previous literature has described rehabilitation considerations for the BPTB and HT autografts, there is less published with respect to the QT. Given the known impact of the various ACLR surgical techniques on postoperative rehabilitation, the purpose of this clinical commentary is to present the procedure-specific surgical and rehabilitation considerations for ACLR with the QT, as well as further highlight the need for procedure-specific rehabilitation strategies after ACLR by comparing the QT to the BPTB and HT autografts.

Level of Evidence

Level 5.

The Associations Between Quadriceps Tendon Graft Thickness and Isokinetic Performance

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) using the quadriceps tendon is an increasingly popular technique. Both partial-thickness quadriceps tendon (PT-Q) and full-thickness quadriceps tendon (FT-Q) graft depths are employed.

HYPOTHESIS/PURPOSE

This study was designed to assess isokinetic peak torque, average power, and total work during knee extension in patients with FT-Q or PT-Q grafts for ACLR. We hypothesized that both groups would show lower isokinetic values for the operated side, with greater deficits in the FT-Q group than in the PT-Q group.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 26 patients who underwent ACLR with either an FT-Q or PT-Q graft were recruited between June 2021 and November 2021. Patients underwent isokinetic knee extension testing at > 1 year after surgery. Mixed repeated-measures analysis of covariance with least square difference post hoc testing was used to determine significant differences or interactions for all variables.

RESULTS

Peak torque was significantly lower for the operated limb than the nonoperated limb in the FT-Q group (mean difference [MD] ± standard error [SE], -38.6 ± 8.3 Nċm [95% CI, -55.7 to -21.5 Nċm]; P < .001; d = 0.90) but not in the PT-Q group (MD ± SE, -7.3 ± 7.7 Nċm [95% CI, -23.2 to 8.5 Nċm]; P = .348; d = 0.20). Similarly, average power for the operated limb was lower than that for the nonoperated limb in the FT-Q group (MD ± SE, -53.6 ± 13.4 W [95% CI, -81.3 to -26.9 W]; P < .001; d = 0.88) but not in the PT-Q group (MD ± SE, -4.1 ± 12.4 W [95% CI, -29.8 to 21.5 W]; P = .742; d = 0.07), and total work was lower for the operated limb compared with the nonoperated limb in the FT-Q group (MD ± SE, -118.2 ± 27.1 J [95% CI, -174.3 to -62.2 J]; P < .001; d = 0.96) but not in the PT-Q group (MD ± SE, -18.3 ± 25.1 J [95% CI, -70.2 to 33.6 J]; P = .472; d = 0.15).

CONCLUSION

The FT-Q group showed significant deficits in the operated limb compared with the nonoperated limb for all isokinetic variables. In contrast, no significant differences were found between the nonoperated and operated limbs for the PT-Q group.

High revision arthroscopy rate after ACL reconstruction in men's professional team sports

PURPOSE

The study analysed unique data on anterior cruciate ligament (ACL) injuries among German professional male team sports over five consecutive seasons with the aim of improving medical outcomes in the future. Sport-specific differences in injury occurrence, concomitant injuries, timing of ACL reconstruction, graft type selection and short-term complications were examined.

METHODS

This retrospective study analysed trauma insurance data on all complete ACL tears from players with at least one competitive match appearance in the two highest divisions of German male basketball, ice hockey, football and handball. Each complete ACL tear registered by clubs or physicians between the 2014/15 and 2018/19 seasons with the German statutory accidental insurance for professional athletes (VBG) as part of occupational accident reporting was included.

RESULTS

In total, 189 out of 7517 players (2.5%) sustained an ACL injury, mainly in handball (n = 82; 43.4%) and football (n = 72; 38.1%) followed by ice hockey (n = 20; 10.6%) and basketball (n = 15; 7.9%).Seventeen players (9.0%) also sustained a second ACL injury. Thus, 206 ACL injuries were included in the analysis. The overall match incidence of ACL injuries was 0.5 per 1000 h and was highest in handballs (1.1 injuries per 1000 h). A total of 70.4% of ACL injuries involved concomitant injury to other knee structures, and 29.6% were isolated ACL injuries. The highest rate of isolated ACL injuries was seen in ice hockey (42.9%). All ACL injuries, except for one career-ending injury, required surgery. In the four analysed team sports, hamstring tendons (71.4%) were the most commonly used grafts for ACL reconstruction; football had the highest percentage of alternative grafts (48.7%). During rehabilitation, 22.9% of all surgically treated ACL injuries (n = 205) required at least two surgical interventions, and 15.6% required revision arthroscopy. The main cause of revision arthroscopy (n = 32; 50.0%) was range-of-motion deficit due to arthrofibrosis or cyclops formation.

CONCLUSION

The present study shows an overall high rate of revision arthroscopy after ACLR (15.6%), which should encourage surgeons and therapists to evaluate their treatment and rehabilitation strategies in this specific subpopulation. Hamstring tendon grafts are most commonly used for ACL reconstruction but have the highest revision and infection rates. Handball shows the highest ACL injury risk of the four evaluated professional team sports. Concomitant injuries occur in the majority of cases, with the highest share of isolated ACL injuries occurring in ice hockey.

LEVEL OF EVIDENCE

Level III.

Predictors of Quadriceps Strength Asymmetry after Anterior Cruciate Ligament Reconstruction: A Chi-Squared Automatic Interaction Detection Decision Tree Analysis

INTRODUCTION

The influence of graft type on the restoration of quadriceps strength symmetry after ACL reconstruction (ACLR) has been widely studied. However, an important consideration when evaluating quadriceps symmetry is the fact that this measure can be influenced by numerous factors beyond graft type. This study sought to determine if graft type is predictive of quadriceps strength asymmetry during the first 12 months post-ACLR taking into consideration potentially influential factors (i.e., age, sex, body mass index, time post-ACLR).

METHODS

We retrospectively reviewed quadriceps strength data from 434 patients (303 female patients and 131 male patients) who had previously undergone ACLR with an autograft (hamstring tendon, quadriceps tendon [QT], patellar tendon [PT]) or allograft. Chi-Squared Automatic Interaction Detection decision tree analysis was used to evaluate if graft type is predictive of quadriceps strength asymmetry during the first 12 months post-ACLR taking into consideration age, sex, body mass index, and time post-ACLR.

RESULTS

The best predictor of quadriceps strength asymmetry was graft type. Specifically, three graft categories were identified: 1) allograft and hamstring tendon autograft, 2) PT autograft, and 3) QT autograft. The average quadriceps strength asymmetry for each of the three identified categories was 0.91, 0.87, and 0.81, respectively, and differed statistically from each other ( P < 0.001). The second-best predictor of quadriceps strength asymmetry was sex, albeit only in the PT and QT groups (with female patients having increased asymmetry). Female patients post-ACLR with a QT autograft were at highest risk for quadriceps strength asymmetry.

CONCLUSIONS

Graft type and sex are important predictors of quadriceps strength asymmetry after ACLR. Clinicians should take these factors into consideration when designing rehabilitation protocols to restore quadriceps strength symmetry during the postoperative period.

Quadriceps tendon autograft for anterior cruciate ligament reconstruction: state of the art

The ideal graft for anterior cruciate ligament reconstruction (ACLR) continues to be debated. Although first described in 1984, use of the quadriceps tendon (QT) autograft has only recently gained popularity. The biomechanical properties of the QT autograft are favourable compared to bone-patellar tendon-bone (BPTB) and doubled hamstring (HS) grafts with a higher load to failure and a modulus of elasticity that more closely approximates the native anterior cruciate ligament (ACL). The QT graft can be harvested with or without a bone plug, as either a full thickness or a partial thickness graft, and even through minimally invasive techniques. The surgeon must be aware of potential harvest risks including patellar fracture or a graft that is of insufficient length. Numerous short-term studies have shown comparable results when compared to BPTB or hamstring HS autografts with similar graft failure rates, patient-reported outcomes. A major advantage of QT ACLR is reduced donor site morbidity compared to BPTB. However, some persistent quadriceps weakness after QT ACLR has also been reported. The current literature shows that use of the QT autograft for ACLR provides equivalent clinical results compared to other autografts with less donor site morbidity. However, future studies with longer follow-up and higher level of evidence are needed to identify specific populations where the QT may have additional advantage.

Anterior cruciate ligament reconstruction using quadriceps tendon autograft is a viable option for small-statured female patients

PURPOSE

The choice of graft for anterior cruciate ligament (ACL) reconstruction remains controversial. The quadriceps tendon (QT) autograft is a good alternative for ACL reconstruction. However, concerns regarding its use in short-statured patients, related to donor site morbidity, anterior knee pain, or loss of muscle strength remain. This study aimed to compare muscle strength and morbidity between patients with short and normal statures following ACL reconstruction with a QT autograft.

METHODS

A total of 73 female patients (mean age, 33.8 ± 11.5 years) who underwent primary ACL reconstruction between 2016 and 2019 were included. Patients were categorized into two groups: group S, with a height ≤ 163 cm, and group L, with a height > 163 cm. Muscle strength, harvesting site morbidity, and ACL-return to sport after injury scale (ACL-RSI) were evaluated, with a mean timing of the follow-up of 9.0 ± 2.3 months.

RESULTS

The mean quadriceps strength for the isokinetic measurements at 60° and 240° was 65.0% and 74.0% in group S, respectively, and 70.0% and 75.7% in group L, respectively. There was no significant difference in the postoperative muscle strength or mean ACL-RSI (group S, 70.0; group L, 65.9) between the groups. No donor site morbidity was observed in either group.

CONCLUSION

Muscle strength recovery, morbidity, and readiness to return to sports were similar in both groups, which supports the possibility of QT autografts for patients with a small stature. The results of this study may provide useful information for surgeons who are hesitant to perform QT autografts because of patient physique.

LEVEL OF EVIDENCE

IV.

Is There an Association in Young Patients Between Quadriceps or Hamstring Strength After ACL Reconstruction and Graft Rupture?

Background:

Younger patients who sustain anterior cruciate ligament (ACL) ruptures are at high risk for reinjury after ACL reconstruction. Restoring muscle strength before return to sports (RTS) is regarded as an important factor in reducing the reinjury risk, and quadriceps and hamstring strength assessment is commonly included in RTS testing. However, it is not clear whether reduced strength is a risk factor for subsequent graft rupture in this patient population.

Purpose:

To investigate the association between quadriceps and hamstring strength at 12 months after primary ACL reconstruction and ACL graft rupture in young patients.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The cohort consisted of 210 patients (100 men and 110 women) who were younger than 20 years at the time of primary ACL reconstruction with a hamstring tendon autograft and who had no previous contralateral ACL injury. Isokinetic strength testing (60 and 180 deg/s) of knee flexors and extensors was performed at 12 months postoperatively, and the limb symmetry index (LSI) for each strength outcome was calculated. RTS rates and the incidence of further ACL graft ruptures were recorded.

Results:

Measures of central tendency (mean and median) of LSI values ranged from 88 to 98. The percentage of patients with LSI ≥90 was 57% to 69% for quadriceps strength and 45% to 47% for hamstring strength. Overall, 19 patients (9%) sustained an ACL graft rupture. No significant differences were found between the patients who sustained an ACL graft rupture and those who did not in terms of quadriceps and hamstring strength at 12 months. No significant associations were found between achieving LSI ≥90 for quadriceps peak torque and subsequent ACL graft rupture.

Conclusion:

In young patients who underwent an ACL reconstruction, no association was noted between quadriceps and hamstring strength at 12 months postoperatively and subsequent graft ruptures. The role of strength testing as part of the RTS criteria after ACL reconstruction, and specifically the use of limb symmetry thresholds, warrants further investigation and clarification.

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery

PURPOSE

The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy.

METHODS

A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions.

RESULTS

There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.).

CONCLUSION

In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery.

LEVEL OF EVIDENCE

II.