Assessment of Flexion Strength Following Single- Versus Double-Hamstring Tendon Harvest for Anterior Cruciate Ligament Reconstruction

The effectiveness of quadrupled semitendinosus graft technique in anterior cruciate ligament reconstruction: A network meta-analysis assessing various graft preparation techniques

PURPOSE

This study aims to perform a network meta-analysis of hamstring graft preparation techniques to enhance anterior cruciate ligament (ACL) reconstruction guidelines and inform clinical decision-making in patients with primary ACL rupture.

METHODS

A review of the literature, from 1 January 1990, to 31 August 2023, was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, focusing on the clinical outcomes of various hamstring graft preparation techniques. Forty-six studies (over 4800 knees) were analysed. Eight graft compositions: doubled hamstring (ST/G)-1978 grafts, doubled hamstring with augmentation (ST/G+A)-586 grafts, tripled semitendinosus (3ST)-124 grafts, quadrupled semitendinosus (4ST)-1273 grafts, five-strand tripled semitendinosus + doubled gracilis (3ST/2GR-839 grafts, six-strand tripled semitendinosus + tripled gracilis (3ST/3GR)-335 grafts, seven-strand quadrupled semitendinosus + tripled gracilis (4ST/3GR)-11 grafts and ≥eight strands-24 grafts were compared, considering graft sizes, laxity, muscle strength, range-of-motion, patient-reported outcome measures (PROMs), return to sport (RTS) and adverse events.

RESULTS

The 4ST grafts fared better than the ST/G grafts in the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS) Sport, KOOS Q and RTS (mean difference [MD], -1.69; p = 0.0159; MD, -1.55; p = 0.0325; MD, -1.93; p = 0.001; odds ratio: 3.13; p < 0.0001). The IKDC differed significantly between the 4ST and ST/G+A groups (MD, 1.88; p = 0.046). The ST/G+A resulted in the lowest knee laxity, surpassing the ST/G, 3ST and 4ST. The ST/G had the smallest diameter (ST/G vs. ST/G+A: MD, 1.26; 95% confidence interval [CI]: 0.67-1.86, p < 0.0001). Reduced failure rates were noted with the 3ST/2GR (3ST/2GR vs. ST/G: MD, 6.93; p = 0.009) and 3ST/3GR (3ST/3GR vs. ST/G: MD, 53.64; p = 0.006).

CONCLUSION

The ideal hamstring graft for ACLR should be individualized. A 4ST graft is likely to yield good PROMs. For high stability and rapid RTS, adding augmentation to the graft is advisable. The ST/G is the thinnest graft possible.

LEVEL OF EVIDENCE

Network meta-analysis of level I-III studies.

Editorial Commentary: Gracilis-Sparing Anterior Cruciate Ligament Hamstring Graft Reconstruction Is Less Invasive Than Semitendinosus-Gracilis Graft Harvest, and Shows No Clinical Difference in Outcomes With Grafts Greater Than 8 mm in Diameter

Although patellar tendon grafts are most commonly used for anterior cruciate ligament reconstruction in the United States, hamstring autograft is most commonly used worldwide. Hamstring advantages include easy, quick harvest; low morbidity; ease of rehabilitation (compared with patellar tendon grafts); and relatively less pain. Historically, both the semitendinosus (ST) and gracilis are harvested, but by doubling, tripling, or quadrupling the ST to achieve an 8-mm graft, the gracilis can be spared, resulting in less knee flexion weakness. However, recent research has shown no clinically important difference between ST and ST-gracilis patient outcomes.

The Addition of the Gracilis Tendon to a Semitendinosus Tendon Autograft Is Not Associated With Knee Muscle Strength, Subjective Knee Function, or Revision Surgery After Anterior Cruciate Ligament Reconstruction

PURPOSE

To evaluate and compare isokinetic knee muscle (extension and flexion) strength, single-leg hop (SLH) test performance, anterior knee laxity, subjective knee function, and the 2-year revision surgery risk between patients who underwent anterior cruciate ligament reconstruction (ACLR) with semitendinosus tendon (ST) autografts and patients who underwent ACLR with ST and gracilis tendon (ST-G) autografts.

METHODS

We identified patients aged 16 years or older who underwent primary ACLR with hamstring tendon autografts at our institution from January 2005 to December 2020 and had no associated ligament injuries. Isokinetic knee muscle strength and SLH test performance were assessed 6 months postoperatively. Anterior knee laxity (KT-1000 arthrometer, 134 N) was assessed preoperatively and 6 months postoperatively. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and 1 and 2 years postoperatively. Patients who underwent revision ACLR at any institution in Sweden within 2 years of primary surgery were identified through the Swedish National Knee Ligament Registry.

RESULTS

A total of 6,974 patients (5,479 with ST and 1,495 with ST-G) were included. There were no significant differences in extension and flexion strength or SLH test performance between the groups. Preoperatively, there was no significant difference in knee laxity between the ST and ST-G groups. Postoperatively, the ST-G group had significantly increased mean side-to-side (STS) laxity (2.1 ± 2.3 mm vs 1.7 ± 2.2 mm, P < .001) and showed a trend toward increased STS laxity according to the International Knee Documentation Committee form, with significantly fewer patients with STS laxity of 2 mm or less (58.4% vs 65.8%) and significantly more patients with STS laxity between 3 and 5 mm (35.0% vs 29.9%) or greater than 5 mm (6.6% vs 4.3%) (P < .001). The only significant difference in subjective knee function was for the KOOS Quality of Life subscale score in favor of the ST group preoperatively (37.3 ± 21.4 vs 35.1 ± 19.9, P = .001). No other significant differences between the groups were found preoperatively and 1 and 2 years postoperatively for any of the KOOS subscales. The overall revision ACLR rate within 2 years of primary surgery was 2.0% (138 of 6,974 patients). The revision ACLR risk in the ST-G group (1.7%, 25 of 1,495 patients) was not significantly different from that in the ST group (2.1%, 113 of 5,479 patients) (hazard ratio, 0.80; 95% confidence interval, 0.50-1.24; P = .32).

CONCLUSIONS

The addition of the gracilis tendon to an ST autograft was not associated with knee muscle strength, SLH test performance, subjective knee function, or the risk of revision surgery after ACLR.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

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.

Hamstring autograft utilization in reconstructing anterior cruciate ligament: Review of harvesting techniques, graft preparation, and different fixation methods

Rupture of the anterior cruciate ligament (ACL) is a common orthopedic injury. Various graft options are available for the reconstruction of ruptured ACL. Using the hamstring muscle as an autograft was first described in 1934, and it remains a commonly harvested graft for ACL reconstruction. Hamstring autografts can be harvested using the traditional anteromedial approach or the newer posteromedial technique. An isolated semitendinosus tendon can be used or combined with the gracilis tendon. There are numerous methods for graft fixation, such as intra-tunnel or extra-tunnel fixation. This comprehensive review discusses the different hamstring muscle harvesting techniques and graft preparation options and fixation methods. It provides a comprehensive overview for choosing the optimal surgical technique when treating patients.

Isokinetic torque analysis demonstrates deficits in knee flexor and extensor torque in patients at 9-12 months after anterior cruciate ligament reconstruction, despite peak torque symmetry

BACKGROUND

Lower limb strength asymmetry is associated with re-injury after anterior cruciate ligament reconstruction (ACLR). This study investigated limb symmetry indices (LSIs) during isokinetic knee extensor and flexor assessment after ACLR.

METHODS

Overall, 25 patients underwent isokinetic knee extensor and flexor strength assessment, 9-12 months after ACLR with a semitendinosus autograft. While patients were included if they presented with peak knee extensor (PKET) and flexor (PKFT) torque LSIs ≥ 90%, LSIs were calculated at designated points throughout the isokinetic torque range of motion, including: 15°, 30°, 45°, 60° and 75° (from 90° of knee flexion) during PKET and 15°, 30°, 45°, 60° and 75° (from full knee extension) during PKFT. T-tests investigated limb differences for PKET and PKFT, as well as at the final 75° assessment point during knee extension and flexion, between: (1) males and females, (2) those that did, or did not, undergo meniscal surgery, and (3) those undergoing ACLR on their dominant or non-dominant limb.

RESULTS

Significant differences between limbs were observed for PKET at 15° (p = 0.040) and 75° (p = 0.002), and for PKFT at 60° (p = 0.001) and 75° (p < 0.0001). No comparative differences (p > 0.05) were seen based on gender, meniscal surgery or whether ACLR was on the dominant or non-dominant limb.

CONCLUSION

Despite 100% of patients demonstrating PKET and PKFT LSIs ≥ 90%, LSI differences existed at designated points throughout the knee extensor and flexor torque range of motion. Analysis of torques throughout full range should be considered in future studies, as comparison of isolated peak measures miss strength deficits.

Knee flexor strength and symmetry vary by device, body position and angle of assessment following ACL reconstruction with hamstring grafts at long-term follow-up

PURPOSE

Persistent deficits in knee flexor strength following harvest of semitendinosus and gracilis for anterior cruciate ligament reconstruction are inconsistent in the literature. Variation in methodology, including measuring torque at higher knee flexion angles may partially explain these discrepant findings. The objective of this study was to determine whether positioning (seated vs supine), consideration of peak or joint-angle-specific torque or device (Isokinetic Dynamometer vs NordBord Hamstring Dynamometer) impact the magnitude of knee flexor strength differences between limbs.

METHODS

Participants (n = 31, 44.2 ± 10.7 years,) who were at 14 ± 4.4 years follow-up for unilateral ACL reconstruction with semitendinosus/gracilis grafts completed the ACL Quality of Life outcome and an assessment including isokinetic concentric knee extensor and flexor strength in seated and supine with peak torque and torque at 60° (T60) and 75° (T75) knee flexion measured, followed by an eccentric Nordic Hamstring Curl.

RESULTS

Isokinetic concentric knee flexor torque was reduced in supine relative to seated, on the reconstructed limb against the unaffected, and at higher degrees of knee flexion relative to peak torque (T60 and T75 against peak torque). Limb symmetry varied by methodology (F_(6,204) = 8.506, p = 0.001) with reduced symmetry in supine T75 against all measures (71.1 ± 16.5%, p < 0.05), supine T60 against seated peak torque (82.7 ± 14.2%, p < 0.05), and the NordBord was lower than seated peak torque that was not statistically significant (83.9 ± 12.8%, n.s.). Knee extensor peak (r² = 0.167 (F_(1,27) = 5.3, p = 0.03) and Nordic curl eccentric torque (r² = 0.267, F_(2,26) = 4.736, p = 0.02) were predictors of ACL-QoL score, although a combined model did not improve over Nordic torque alone.

CONCLUSION

Limb symmetry cannot be assumed in clinical practice across differing assessment methods for knee flexor strength as deficits are greatest in the supine position with torque measured at 75° knee flexion. Isokinetic knee extensor and eccentric knee flexor torque during the Nordic hamstring curl were predictors of ACL-QoL scoring and should be considered alongside patient-reported outcomes for patients following ACL reconstruction with hamstring grafts.

LEVEL OF EVIDENCE

Level IV.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

BACKGROUND

To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively.

HYPOTHESIS

The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively.

STUDY DESIGN

Retrospective cohort study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping.

RESULTS

Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups.

CONCLUSION

The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively.

CLINICAL RELEVANCE

Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

Editorial Commentary: Anterior Cruciate Ligament Autograft Morbidity: Who Needs Strong Hamstrings in Greater Than 90° of Knee Flexion?

An understanding of expected morbidity of various anterior cruciate ligament graft options is important to inform patient expectations and facilitate successful return to sport following anterior cruciate ligament reconstruction. Hamstring harvest results in decreased hamstring strength. Gracilis preservation may mitigate the degree of strength loss, particularly in deep knee flexion. The extent to which knee flexion strength at high flexion angles is important to return to play and functional outcomes remains unknown and is likely sport-dependent.