Graft Diameter and Graft Type as Predictors of Anterior Cruciate Ligament Revision: A Cohort Study Including 18,425 Patients from the Swedish and Norwegian National Knee Ligament Registries

Diameter of quadrupled semitendinosus autograft in primary anterior cruciate ligament reconstruction did not impact early revision rate or functional outcome in a large cohort of patients

PURPOSE

To determine whether the diameter of the quadrupled semitendinosus tendon (ST) graft in primary anterior cruciate ligament reconstruction (ACLR) is related to the risk of revision ACLR within 2 years of primary ACLR, postoperative knee laxity and patient reported knee outcome. Furthermore, to investigate whether smaller graft than estimated is related to revision ACLR.

METHODS

Patients who underwent primary ACLR with a quadrupled ST autograft at our institution, from January 2005 to December 2017 were identified. Data from the Swedish National Knee Ligament Registry (SNKLR) were collected up to two years or until revision surgery was registered within two years after primary ACLR. Knee laxity was assessed, pre-operatively and at 6-months follow up using the KT-1000 arthrometer (134 N anterior tibial load). The Knee injury and Osteoarthritis Outcome Score (KOOS) were collected preoperatively and at two years postoperatively from SNKLR. Based on anthropometric measurements (body height and weight) and sex the estimated quadrupled ST graft diameter was calculated.

RESULTS

A total of 4,519 patients who underwent ACLR with a quadrupled ST autograft were included. The mean graft diameter was 8.3 mm± 0.7 mm; 8.0 mm± 0.6 mm for women and 8.6 mm ± 0.7 mm for men. The quadrupled ST graft diameter was not significantly correlated to revision ACLR. There was no significant difference in the ST graft diameter regarding post-operative knee laxity. The correlations between ST graft diameter and KOOS were weak, except for the "Sport and Recreation" subscale (P=.012).

CONCLUSIONS

The quadrupled ST graft diameter was not significantly related to the need for early revision ACLR nor was related to postoperative knee laxity or patient reported outcome except for the KOOS "Sport and Recreation" subscale. Smaller ST graft than estimated was not a risk factor for revision ACLR. The outcome after ACLR is multifactorial and ST graft diameter is of no significant importance.

Four-year comparative analysis of return to sport and psychological recovery following ACL revision: Artificial ligament vs. anterior tibial tendon allograft

Background

Research on return to sport and psychological recovery in anterior cruciate ligament (ACL) revision remains scarce. The clinical efficacy of artificial ligament in ACL revision requires further exploration. Our objectives were (1) to compare the midterm clinical outcomes of artificial ligament versus allogenic tendon graft in ACL revision and (2) to analyze the effects of employing artificial ligament on return to sport and psychological recovery in ACL revision.

Methods

This cohort study included the cases receiving ACL revision from 2014 to 2021 in Sports Medicine Department of Huashan Hospital. The grafts used were Ligament Advanced Reinforcement System (LARS) and ATT allograft. We recorded patients' baseline data. The final follow-up assessment included subjective scales, physical examination, and return to sport status. We recorded the rates and timings of return to sport. Subjective scales included the 2000 International Knee Documentation Committee (IKDC) subjective score, Lysholm Knee Scaling Score (LKSS), Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner activity score, Marx activity rating score, and Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI). Anterior knee stability was assessed using the KT-1000 arthrometer.

Results

Fifty cases (LARS group: 27; ATT group: 23) enrolled and 45 (LARS group: 23; ATT group: 22) completed evaluations with a median follow-up period of 49 months. At recent follow-up, LARS group outperformed in knee stability (1.0 ± 1.9 mm vs. 2.6 ± 3.0 mm, P = 0.039), confidence (86.7 ± 12.4 vs. 69.4 ± 18.6, P < 0.001), emotion (82.7 ± 11.3 vs. 70.7 ± 16.2, P < 0.001), KOOS knee function (78.7 ± 8.8 vs. 69.5 ± 11.0, P = 0.003), quality of life (79.1 ± 16.1 vs. 66.4 ± 19.5, P = 0.014), Tegner score (6.3 ± 1.9 vs. 5.2 ± 2.1, P < 0.001), and Marx activity score (10.7 ± 3.7 vs. 7.9 ± 4.0, P = 0.012). The LARS group had significantly higher return rates: recreational (91.3 % vs. 63.6 %, P = 0.026), knee cutting and pivoting (87.0 % vs. 59.1 %, P = 0.035), competitive (78.3 % vs. 45.5 %, P = 0.023), and pre-injury (56.5 % vs. 27.3 %, P = 0.047). For return timings, the LARS group was earlier at recreational (11.2 ± 3.9 vs. 27.8 ± 9.0 weeks, P < 0.001), knee cutting and pivoting (17.2 ± 5.8 vs. 35.6 ± 13.8 weeks, P < 0.001), competitive (24.8 ± 16.2 vs. 53.2 ± 22.0 weeks, P < 0.001), and pre-injury levels (32.8 ± 11.0 vs. 72.8 ± 16.9 weeks, P < 0.001).

Conclusion

In ACL revision, using LARS demonstrated improved joint stability and functionality compared to using allogenic ATT four years postoperative. Patients accepting the LARS procedure exhibited higher rates and earlier timings of return to various levels of sport, indicating enhanced confidence and emotional resilience.

The translational potential of this article

In ACL revision, the choice of artificial ligament to shorten recovery time, thereby enabling patients to return to sport more quickly and effectively, is thought-provoking. The research value extends beyond mere graft selection, guiding future clinical trials and studies. This research enhances our understanding of the application value of artificial ligament in ACL revision, emphasizing the importance of psychological recovery and updating our perceptions of return to sport levels post-revision. It stimulates exploration into personalized rehabilitation programs and treatment strategies, aiming to optimize clinical outcomes and meet the real-world needs of patients with failed ACL reconstruction.

Tendon cross-sectional area on magnetic resonance imaging and anthropometric characteristics can be used to predict insufficient four-strand hamstring autograft diameter in anterior cruciate ligament reconstruction: A systematic review

PURPOSE

To evaluate the utility of semitendinosus tendon (ST) and gracilis tendon (GT) cross-sectional area (CSA) on magnetic resonance imaging (MRI) and anthropometric characteristics in preoperative estimation of graft diameter in patients undergoing anterior cruciate ligament reconstruction (ACLR) with four-strand hamstring autografts.

METHODS

Three databases were searched on 29 August 2023. The authors adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and R-AMSTAR (Revised Assessment of Multiple Systematic Review) guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, anthropometric characteristics, imaging techniques, tendon CSA, correlation coefficients, sensitivities, specificities, regression models and cutoffs for predicting intraoperative graft diameters above 8 mm were recorded.

RESULTS

Forty-six studies comprising 4140 patients were included. Twelve of 19 (63.2%) studies reporting on ST + GT CSA found a moderate to very high correlation with intraoperative graft diameter. Five of 10 (50%) and one of seven (14.3%) studies reporting on ST CSA and GT CSA, respectively, found a moderate to high correlation with intraoperative graft diameter. Cutoffs of ST + GT CSA for predicting graft diameters above 8 mm ranged from 15.8 to 31.2 mm2. Nine of 35 (25.7%) studies that reported on height found a moderate to very high correlation with graft diameter. Seven of 33 (21.2%) studies reporting on weight found a moderate correlation with graft diameter.

CONCLUSION

Of the MRI parameters assessed, ST + GT CSA was the most reliable predictor of graft diameter. However, cutoffs, sensitivities, and specificities for predicting diameters above 8 mm were highly variable. Anthropometric characteristics in general were less predictive of graft diameter than MRI parameters. This information can be used by clinicians to predict patients at risk for ACLR failure due to insufficient graft size.

LEVEL OF EVIDENCE

Level IV.

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.

Influence of female sex and double-quadruple semitendinosus-gracilis graft on the incidence of postoperative symptomatic cyclops lesions after ACL reconstruction

PURPOSE

Risk factors for the development of symptomatic cyclops lesion after anterior cruciate ligament reconstruction (ACLR) surgery are not entirely identified yet. This study aimed to investigate whether the choice of hamstring graft (semitendinosus-gracilis; STG vs. semitendinosus; ST) affects the risk of developing a symptomatic cyclops lesion after ACLR.

METHODS

This retrospective cohort study included 1416 patients receiving either an ST graft (n = 1209) or an STG graft (n = 207) ACLR with a follow-up of at least 2 years. A persisting extension limitation was clinically determined, and cyclops lesions were confirmed by magnetic resonance imaging (MRI) and second-look arthroscopy. Graft-specific incidence of cyclops lesions was examined with χ2 test and combined with the factors number of graft bundles, graft diameter and sex evaluated with a binominal logistic regression model.

RESULTS

In total, 46 patients developed symptomatic cyclops lesions (3.2%), with 36 having ACLR with an ST graft (3.0%) and 10 with an STG graft (4.8%) (n.s). The mean time from ACLR to the second-look arthroscopy for cyclops removal was 1.1 ± 0.6 years. Female patients were 2.5 times more likely to develop a cyclops lesion than male patients. Patients with an STG graft and larger graft diameters did not have a higher risk of developing cyclops lesions. Patients who received an STG graft with both tendons folded four times (double-quadruple) had significantly higher risk of developing a cyclops compared with all other numbers of graft bundles combined (8.3%, respectively 3.0%; p = 0.014).

CONCLUSION

This study could not prove an increased risk of developing a symptomatic cyclops lesion for patients with an STG graft compared with an ST graft used for ACLR. However, patients with a double-quadruple ACLR had a higher percentage of cyclops lesions compared with all other numbers of graft bundles. Female sex was associated with an increased risk of developing cyclops lesions.

LEVEL OF EVIDENCE

Level III.

Validating the capture rate of revisions by the New Zealand ACL Registry: An analysis of all-cause reoperation following primary ACL reconstruction

PURPOSE

To validate the New Zealand Anterior Cruciate Ligament (ACL) Registry's capture rate of revisions by cross-referencing Registry data with reoperations data recorded by the Accident Compensation Corporation (ACC) and identify risk factors for all-cause reoperation.

METHODS

Primary ACL reconstructions performed between April 2014 and September 2019 were individually matched on a record-by-record basis between the two databases. The ACC database was used to identify patients who underwent a reoperation with manual review of operation notes to identify whether a revision or other procedure was performed. This was combined with the number of revisions separately recorded in the New Zealand ACL Registry, which was used as the denominator value to calculate the Registry's capture rate of revisions. Patient and surgical data recorded in the Registry were analysed to identify independent predictors for all-cause reoperation.

RESULTS

A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and the ACC databases. The reoperation rate was 8.9% (n = 715) at a mean follow-up of 2.5 years. Meniscal-related procedures were the most common reoperation (n = 299, 3.7%), followed by revision ACL reconstruction (n = 219, 2.7%), arthrofibrosis (n = 185, 2.3%), cartilage (n = 56, 0.7%) and implants (n = 32, 0.4%). The New Zealand ACL Registry captured 96% of revisions. Younger age (hazard ratio [HR] > 1.4, p < 0.001), earlier surgery (HR > 1.3, p = 0.05), concurrent meniscal repair (medial meniscus HR = 1.9, p < 0.001 and lateral meniscus HR = 1.3, p = 0.022) and hamstring tendon autografts (HR = 1.4, p = 0.001) were associated with a higher risk of reoperation.

CONCLUSION

The New Zealand ACL Registry captured 96% of revisions. Risk factors for all-cause reoperation included younger age, earlier surgery, meniscal repair and hamstring tendon autografts.

LEVEL OF EVIDENCE

Level III.

Peroneus Longus Tendon Autograft May Present a Viable Alternative for Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To examine the available literature to better understand the objective and patient-reported outcomes using peroneus longus tendon (PLT) autograft compared with more commonly used autografts, such as the quadrupled hamstring tendons (HT), in patients undergoing primary for anterior cruciate ligament reconstruction (ACLR).

METHODS

A comprehensive search of published literature in PubMed, Web of Science, Cochrane Library, Ovid, and EMBASE databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria included patients undergoing ACLR with PLT autograft, inclusion of patient-recorded outcome measures, and availability in English language. Publications that included only biomechanical analysis or ACLR with use of allograft or combination grafts were excluded.

RESULTS

A total of 16 studies (Level of Evidence range: I-IV) met inclusion criteria, with follow-up ranging from 3 months to 5 years. In the available case series, patient-reported outcomes ranged from Lysholm = 80.7 to 95.1, International Knee Documentation Committee 78.1 to 95.7. In prospective cohorts and randomized controlled trials, PLT performance was comparable with HT autografts (PLT/HT: Lysholm = 88.3-95.1/86.5-94.9, International Knee Documentation Committee = 78.2-92.5/87.4-93.4). The majority of PLT grafts diameters were equal or greater than HT counterparts with a mean of >8 mm (PLT/HT: 7.0-9.0 mm/7.65-8.5 mm). There was minimal donor-site morbidity associated with PLT harvest.

CONCLUSIONS

Although limitations exist within the available literature, existing evidence suggests that PLT autograft routinely produces adequately sized grafts with comparable early outcomes to HT autograft and low risk of donor-site morbidity. However, the PLT autograft is yet to demonstrate superiority to any of the more-traditional autograft selections.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Outcomes of "Over the Top" Anterior Cruciate Ligament Reconstruction Associated with a Lateral Extra-Articular Tenodesis in Children

(1) Purpose: The incidence of anterior cruciate ligament (ACL) ruptures in children and adolescents has considerably increased during the last decades due to higher levels of competitive athletic activity, and early sport specialization and professionalization. Contemporary ACL reconstruction techniques have recently been subject to renewed interest in this population. The objective of this study is to report the short- and mid-term results of our physis-sparing ACL reconstruction technique using an "over the top" technique associated with a modified Lemaire procedure. (2) Methods: A retrospective series of 12 junior soccer players who presented to our clinic with a torn ACL between January 2019 and September 2021 was reviewed. The inclusion criteria were patients under 15 years with open tibial and femoral physes, with a stable contralateral knee, a minimum follow-up of 6 months, and a time frame from injury to surgery of <3 months. Patients with previous knee surgery, structural concomitant injuries, muscular, neurological, or vascular abnormalities, or hypersensitivity to metal alloys were excluded. The functional evaluation was performed using the International Knee Documentation Committee (IKDC) rating, Lysholm score, and Tegner activity level. Moreover, clinical and radiological assessments were also performed, including KT-1000 and knee X-rays. (3) Results: We identified 1 female and 11 male patients with ACL tears, with a mean age of 13.17 ± 0.9 months. Concomitant injuries include isolated vertical and bucket-handle tears of the medial meniscus, lateral meniscus tears, bilateral tear of both menisci. The mean follow-up time was 26 ± 12.6 months. The average IKDC, Lysholm and Tegner scores were 93.29 ± 11.04, 95.08 ± 13.2 and 9 ± 0.0 points, respectively. The average KT-1000 score of the participants was 0.96 ± 1.6 points. None of the included patients reported post-surgical complications or required additional surgeries. (4) Conclusions: Our novel ACL reconstruction with LET technique is a safe procedure that resulted in good clinical outcomes, lower failure rate and return to sports in skeletally immature patients.

Increased risk for early revision with quadriceps graft compared with patellar tendon graft in primary ACL reconstructions

PURPOSE

Bone patella-tendon bone (BPTB) and hamstring tendon (HT) autografts are the most used grafts in primary anterior cruciate ligament (ACL) reconstructions (ACLR) in Norway. Quadriceps tendon (QT) autograft has gained more popularity during the past years. The purpose of this study is to compare revision rates and patient-reported outcomes of primary QT with BPTB and HT autograft ACL reconstructions in Norway at 2-year follow-up. It was hypothesized that there would be no difference in 2-year revision rates between all three autografts.

METHODS

Data included primary ACLR without concomitant ligament surgeries, registered in the Norwegian Knee Ligament Register from 2004 through 2021. Revision rates at 2 years were calculated using Kaplan-Meier analysis. Hazard ratios (HR) for revision were estimated using multivariable Cox regression analysis with revision within 2 years as endpoint. Mean change in patient-reported outcome was recorded preoperatively and at 2 years through the Knee Injury and Osteoarthritis Outcome Score (KOOS) subcategories 'Sport' and 'Quality of Life' was measured for patients that were not revised and analysed with multiple linear regression.

RESULTS

A total of 24,790 primary ACLRs were identified, 10,924 with BPTB, 13,263 with HT and 603 with a QT graft. Patients in the QT group were younger (23.5 years), more of them were women (58.2%) and over 50% had surgery <3 months after injury. The QT group had the highest prevalence of meniscal injuries (61.9%). Revision estimates at 2-years were 3.6%, 2.5% and 1.2% for QT, HT and BPTB, respectively (p < 0.001). In a Cox regression analysis with QT as reference, BPTB had a lower risk of revision (HR 0.4, 95% Cl 0.2-0.7, p < 0.001). No significant difference was observed in the revision risk between QT and HT (HR 1.1, 95% Cl 0.7-1.8, n.s.). The two most common reported reasons for revision were: traumatic graft rupture and nontraumatic graft failure. There were no differences between the groups in change of KOOS in subcategories 'Sport' and 'Quality of Life' at 2-years follow-up.

CONCLUSION

The 2-year risk of revision after ACLR with QT was higher than BPTB and similar to HT. No difference was found between the groups in patient-reported outcomes. This study provides valuable insights for both surgeons and patients when making decisions about the choice of autografts in primary ACL reconstructions.

LEVEL OF EVIDENCE

Level II.

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.

Small Intercondylar Notch Size Is Not Associated with Poor Surgical Outcomes of Anatomical Single-Bundle Anterior Cruciate Ligament Reconstructions

Background

Although many studies have been conducted on the association between the intercondylar notch size and the risk of anterior cruciate ligament (ACL) injury, few studies have examined its relationship with the condition after surgical treatment. Therefore, this study aimed to investigate the surgical outcomes of anatomical single-bundle ACL reconstruction according to intercondylar notch volumes.

Methods

Medical records of patients who underwent anatomical single-bundle ACL reconstruction using a tibialis anterior allograft between 2015 and 2019 were retrospectively reviewed. For each sex, eligible patients were classified into two groups based on their percentile of intercondylar notch volumes, which were measured using postoperative three-dimensional computed tomography images (group S, ≤ 50th percentile of included patients; group L, > 50th percentile of included patients). Additional grouping was performed based on the group's percentiles of normalized values of intercondylar notch volumes to body heights. Between-group comparative analyses were performed on the perioperative data and surgical outcomes in both objective and subjective aspects.

Results

One hundred patients were included in the study. For male patients, there were no differences in the overall surgical outcomes between groups, whereas group L showed a significantly greater knee anteroposterior (AP) laxity than group S at the final follow-up (p = 0.042 for the side-to-side differences [SSD] at the maximum manual force). Similarly, there were no differences in the female patients in the overall surgical results between the groups, whereas group L showed a significantly greater knee AP laxity at the final follow-up (p = 0.020 for the SSD at 134 N; p = 0.011 for the SSD at the maximum manual force). Additional analyses based on the normalized values of the intercondylar notch volume showed consistent results for male patients, and additional grouping for female patients was identical to the existing grouping.

Conclusions

The surgical outcomes of anatomical single-bundle ACL reconstruction in patients with relatively small intercondylar notch volumes were comparable to those with large notch volumes, but rather showed favorable outcomes in postoperative knee AP laxity.

Estimation Failure Risk by 0.5-mm Differences in Autologous Hamstring Graft Diameter in Anterior Cruciate Ligament Reconstruction: A Meta-analysis

BACKGROUND

Because grafts are made in 0.5-mm increments clinically for anterior cruciate ligament (ACL) reconstruction, it is important to clarify how the failure rate decreases as the diameter increases. Moreover, it is important to know whether even a slight increase in the graft diameter decreases the risk of failure.

HYPOTHESIS

The risk of failure decreases significantly with each 0.5-mm increase in hamstring graft diameter.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The systematic review and meta-analysis have estimated the diameter-specific failure risk for each 0.5-mm increase in ACL reconstruction using autologous hamstring grafts. We searched for studies describing the relationship between graft diameter and failure rate published before December 1, 2021, in leading databases, such as PubMed, EMBASE, Cochrane Library, and Web of Science, according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We included studies using single-bundle autologous hamstring grafts to investigate the relationship between failure rate and graft diameter of 0.5-mm intervals with >1-year follow-up. Then, we calculated the failure risk caused by 0.5-mm differences in autologous hamstring graft diameter. Assuming Poisson distribution for the statistical model, we employed an extended linear mixed-effects model in the meta-analyses.

RESULTS

Five studies containing 19,333 cases were eligible. The meta-analysis revealed that the estimated value of the coefficient of diameter in the Poisson model was -0.2357 with a 95% CI of -0.2743 to -0.1971 (P < .0001). With every 1.0-mm increase in diameter, the failure rate decreased by 0.79 (0.76-0.82) times. In contrast, the failure rate increased by 1.27 (1.22-1.32) times for each 1.0-mm decrease in diameter. The failure rate significantly decreased with each 0.5-mm increase in graft diameter in the range of <7.0 to >9.0 mm from 3.63% to 1.79%.

CONCLUSION

The risk of failure decreased correspondingly with each 0.5-mm increase in graft diameter in the range of <7.0 to >9.0 mm. Failure is multifactorial; however, increasing the graft diameter as much as possible to match each patient's anatomic space without overstuffing is an effective precaution that surgeons can take to reduce failures.

A hamstring autograft diameter ≤ 8 mm is a safe option for smaller, lighter and female athletes who want to return to pivoting sports after ACL reconstruction : Results from a retrospective evaluation of a local ACL register

PURPOSE

To investigate the association between hamstring autograft diameter and ACL graft failure rate in athletes who successfully returned to pivoting sports after ACL reconstruction.

METHODS

Retrospective evaluation of ACL graft failure rates in athletes who underwent ACL reconstruction with all-inside hamstring autograft and successfully returned to pivoting sports following postoperative rehabilitation. Athletes were divided into a ≤ 8 mm group and a > 8 mm group. Data about return to pivoting sports and ACL graft failures after ACL reconstruction were collected via a digital questionnaire. ACL graft failures were in all cases confirmed by an orthopaedic surgeon and/or MRI. The association between hamstring autograft diameter and ACL graft failure rate was investigated using a Fisher's exact test in the subgroup of athletes who completed the digital questionnaire and returned to pivoting sports.

RESULTS

Two-hundred and twenty-nine of the 422 athletes who completed the digital questionnaire (54.2%) returned to a pivoting sport and were included for final analyses. Ninety-seven (42.4%) of the athletes who returned to sport were in the ≤ 8 mm group (8 graft failures) and 132 (57.6%) in the > 8 mm group (10 graft failures). There were significantly more women (49.5 and 13.6% respectively; p < 0.001) and significantly smaller (1.75 and 1.81 m respectively; p < 0.001), lighter (72.2 and 79.6 kg respectively; p < 0.001) and younger (23.6 and 26.1 years old respectively; p = 0.015) athletes in the ≤ 8 mm group compared to the > 8 mm group. There was no significant association between hamstring autograft diameter and ACL graft failure rate.

CONCLUSION

A hamstring autograft diameter of ≤ 8 mm is a legitimate option for smaller, lighter and female athletes without increasing the risk for ACL graft failure.

LEVEL OF EVIDENCE

III.

A Web-Based Prediction Tool to Improve Identification of Patients With Undersized Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction

BACKGROUND

An undersized hamstring tendon (HT) autograft is significantly associated with a higher graft failure rate in anterior cruciate ligament reconstruction (ACLR) surgery. The ability to accurately predict inadequate HT graft diameter is critical, as it could assist surgeons in making better graft choices and surgical plans.

PURPOSE

To develop a web-based prediction tool to better assess the size of HT autograft and to help clinicians accurately identify patients with potentially undersized HT grafts in order to make appropriate clinical decisions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 588 patients who received primary arthroscopic single-bundle ACLR surgery with gracilis tendon (GT) and semitendinosus tendon (ST) autograft were retrospectively reviewed. According to the size of 4-strand HT graft, patients were divided into diameter ≥8 mm and <8 mm groups. The least absolute shrinkage and selection operator method and logistic regression were used to identify the independent factors associated with HT graft diameter and establish the models. The prediction performance of the model was evaluated by concordance index and calibration combined with external validation. The diagnostic performance of the prediction model was assessed by sensitivity, specificity, predictive values, and likelihood ratios. Decision curve analysis was used to evaluate the clinical utility of the model.

RESULTS

Among the numerous indicators, sex, weight, height, thigh length, and ST-GT diameter (measured on plane 1 of a magnetic resonance imaging scan) were identified to be highly correlated predictors that could provide satisfactory prediction performance in determining the HT graft diameter. Based on these predictors, a prediction model named the HTD model was developed with satisfactory discrimination (concordance index, 0.932) and calibration (mean absolute error, 0.039). When the probability calculated by the HTD model was >65%, the sensitivity and specificity of predicting 4-strand HT graft diameter ≥8 mm were 86.7% and 90.2%, respectively.

CONCLUSION

As a useful supplementary prediction tool, the HTD model could accurately predict the diameter of HT autograft during preoperative planning.

Interference screws manufactured from magnesium display similar primary stability for soft tissue anterior cruciate ligament graft fixation compared to a biocomposite material - a biomechanical study

PURPOSE

Biodegradable interference screws (IFS) can be manufactured from different biomaterials. Magnesium was previously shown to possess osteoinductive properties, making it a promising material to promote graft-bone healing in anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare IFS made from magnesium to a contemporary biocomposite IFS.

METHODS

In a porcine model of ACL reconstruction, deep porcine flexor tendons were trimmed to a diameter of 8 mm, sutured in Krackow technique, and fixed with either 8 × 30 mm biocomposite IFS (Bc-IFS) or 8 × 30 mm magnesium IFS (Mg-IFS) in an 8 mm diameter bone tunnel in porcine tibiae. Cyclic loading for 1000 cycles from 0 to 250 N was applied, followed by load to failure testing. Elongation, load to failure and stiffness of the tested constructs was determined.

RESULTS

After 1000 cycles at 250 N, elongation was 4.8 mm ± 1.5 in the Bc-IFS group, and 4.9 mm ± 1.5 in the Mg-IFS group. Load to failure was 649.5 N ± 174.3 in the Bc-IFS group, and 683.8 N ± 116.5 in the Mg-IFS group. Stiffness was 125.3 N/mm ± 21.9 in the Bc-IFS group, and 122.5 N/mm ± 20.3 in the Mg-IFS group. No significant differences regarding elongation, load to failure and stiffness between Bc-IFS and Mg-IFS were observed.

CONCLUSION

Magnesium IFS show comparable biomechanical primary stability in comparison to biocomposite IFS and may therefore be an alternative to contemporary biodegradable IFS.

Poorer patient-reported outcome and increased risk of revision at a 5-year follow-up among patients with septic arthritis following anterior cruciate ligament reconstruction: a register-based cohort study of 23,075 primary anterior cruciate ligament reconstructions

PURPOSE

The primary aim of this study is to analyse the patient-reported outcomes after ACLR complicated by septic arthritis. The secondary aim is to examine the 5-year risk of revision surgery after primary ACLR complicated by septic arthritis. The hypothesis was that patients with septic arthritis after ACLR are more likely to have lower PROMs scores and an increased risk of revision, compared with patients without septic arthritis.

MATERIALS AND METHODS

All primary ACLRs, with a hamstring or patellar tendon autograft (n = 23,075), in the Swedish Knee Ligament Register (SKLR) between 2006 and 2013 were linked with data from the Swedish National Board of Health and Welfare to identify patients with postoperative septic arthritis. These patients were verified in a nationwide medical records analysis and compared with patients without infection in the SKLR. The patient-reported outcome was measured using the Knee injury and Osteoarthritis Index Score (KOOS) and the European Quality of Life Five Dimensions Index (EQ-5D) at 1, 2 and 5 years postoperatively and the 5-year risk of revision surgery was calculated.

RESULTS

There were 268 events of septic arthritis (1.2%). The mean scores on the KOOS and EQ-5D index were significantly lower for patients with septic arthritis on all subscales on all follow-up occasions compared with patients without septic arthritis. Patients with septic arthritis had a revision rate of 8.2% compared with 4.2% in patients without septic arthritis (adjusted hazard ratio 2.04; confidence interval 1.34-3.12).

CONCLUSION

Patients suffering from septic arthritis following ACLR are associated with poorer patient-reported outcomes at 1-, 2- and 5-year follow-ups compared with patients without septic arthritis. The risk of revision ACL reconstruction within 5 years of the primary operation for patients with septic arthritis following ACLR is almost twice as high, compared with patients without septic arthritis.

LEVEL OF EVIDENCE

III.

Anterior cruciate ligament injuries in female athletes

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females' greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries.

Cohort study of short-term outcomes after ACL-reconstruction using autograft with internal brace reinforcement versus isolated autograft demonstrating no significant difference

Background

The gold standard treatment for Anterior Cruciate Ligament injury is reconstruction (ACL-R). Graft failure is the concern and ensuring a durable initial graft with rapid integration is crucial. Graft augmentation with implantable devices (internal brace reinforcement) is a technique purported to reduce the risk of rupture and hasten recovery. Few studies have examined these techniques, in particular when compared to non-augmented grafts. This study assesses the short-term outcome of ACL-R using augmented and non-augmented hamstring tendon autografts.

Methods

This was a retrospective cohort study comparing augmented and non-augmented ACL-R. All procedures were performed in a single centre using the same technique. The Knee injury and Osteoarthritis Outcome Score [KOOS] was used to assess patient-reported outcomes.

Results

There were 70 patients in the augmented and 111 patients in the control group. Mean graft diameter in the augmented group was 8.82 mm versus 8.44 mm in the non-augmented. Six strand graft was achievable in 73.5% of the augmented group compared to 33% in the non-augmented group. Two graft failures were reported in the non-augmented group and none in the augmented group. Patient satisfaction rates were higher in the augmented group. There was a statistically insignificant improvement in the postoperative KOOS in the augmented group compared to the non-augmented group (p 0.6). Irrespective of augmentation status, no correlation was found between the functional score and age, or femoral tunnel width.

Conclusion

No statistically significant difference was demonstrated in the short-term functional outcome of ACL reconstruction using an augmented or non-augmented hamstring graft. Augmented ACL-R may achieve superior graft diameters, failure rates and patient reported outcomes when compared to nonaugmented ACL-R. Prospective trials are needed to examine this further.

Relationship between graft failure following anterior cruciate ligament reconstruction and hamstring autograft diameter

With the increase in the number of individuals participating in sports, anterior cruciate ligament (ACL) injuries are also increasing gradually and the number of patients requiring surgical treatment is increasing in parallel. The primary aim of this study was to investigate the relationship between the need for revision surgery and graft diameter following primary ACL reconstruction (ACLR) using hamstring autografts. The secondary aim of the study was to clarify relationships between anthropometric characteristics and graft diameter. Patients who underwent ACLR with hamstring autografts were included in this retrospective study. The age, body mass index, height, and weight of all patients were recorded preoperatively and the diameters of the grafts were recorded during surgery. The relationship between revision rate and graft diameter and the relationships between anthropometric measurements and graft diameter were investigated for these patients at least one year after surgery. This study included 58 people with graft diameters of ≤7 mm and 261 people with graft diameters of >7 mm. A statistically significant difference was found between the graft diameters of the group that needed revision surgery and the group that did not (p<0.001). A positive relationship was also found between the patient's height and graft diameter (r=0.168). In this study, it was found that the risk of ACL revision surgery increased by 5.5 times among patients with graft diameters of ≤7 mm. The positive relationship between the patient's height and graft diameter can make a significant difference in terms of the need for revision surgery.

Risk Factors for Revision or Rerupture After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

The rerupture or need for revision after anterior cruciate ligament reconstruction (ACLR) is a serious complication. Preventive strategies that target the early identification of risk factors are important to reduce the incidence of additional surgery.

PURPOSE

To perform a systematic review and meta-analysis to investigate risk factors for revision or rerupture after ACLR.

STUDY DESIGN

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

METHODS

Literature searches were performed in PubMed, Embase, and Web of Science from database inception to November 2021 and updated in January 2022. Quantitative, original studies reporting potential adjusted risk factors were included. Odds ratios (ORs) were calculated for potential risk factors.

RESULTS

A total of 71 studies across 13 countries with a total sample size of 629,120 met the inclusion criteria. Fifteen factors were associated with an increase in the risk of revision or rerupture after ACLR: male sex (OR, 1.27; 95% CI, 1.14-1.41), younger age (OR, 1.07; 95% CI, 1.05-1.08), lower body mass index (BMI) (OR, 1.03; 95% CI, 1.00-1.06), family history (OR, 2.47; 95% CI, 1.50-4.08), White race (OR, 1.32; 95% CI, 1.08-1.60), higher posterolateral tibial slope (OR, 1.15; 95% CI, 1.05-1.26), preoperative high-grade anterior knee laxity (OR, 2.30; 95% CI, 1.46-3.64), higher baseline Marx activity level (OR, 1.07; 95% CI, 1.02-1.13), return to a high activity level/sport (OR, 2.03; 95% CI, 1.15-3.57), an ACLR within less than a year after injury (OR, 2.05; 95% CI, 1.81-2.32), a concomitant medial collateral ligament (MCL) injury (OR, 1.62; 95% CI, 1.31-2.00), an anteromedial portal or transportal technique (OR, 1.36; 95% CI, 1.22-1.51), hamstring tendon (HT) autografts (vs bone-patellar tendon-bone [BPTB] autografts) (OR, 1.60; 95% CI, 1.40-1.82), allografts (OR, 2.63; 95% CI, 1.65-4.19), and smaller graft diameter (OR, 1.21; 95% CI, 1.05-1.38). The other factors failed to show an association with an increased risk of revision or rerupture after ACLR.

CONCLUSION

Male sex, younger age, lower BMI, family history, White race, higher posterolateral tibial slope, preoperative high-grade anterior knee laxity, higher baseline Marx activity level, return to a high activity level/sport, an ACLR within less than a year from injury, a concomitant MCL injury, an anteromedial portal or transportal technique, HT autografts (vs BPTB autografts), allografts, and smaller graft diameter may increase the risk of revision or rerupture after ACLR. Raising awareness and implementing effective preventions/interventions for risk factors are priorities for clinical practitioners to reduce the incidence of revision or rerupture after ACLR.

Anatomic Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament reconstruction (ACLR) techniques have substantially evolved over the past several decades, driven by evidence that nonanatomic techniques increase the risk for instability, loss of motion, surgical failure, and posttraumatic osteoarthritis. Early techniques used transtibial femoral tunnel drilling, although improved understanding of the anatomy and biomechanics has led to independent femoral tunnel. Anatomic ACLR requires careful consideration of the native ACL dimensions and orientation. Although there is significant variation between patients, understanding of anatomic patterns allows for reliable identification of the ACL footprints and appropriate tunnel positioning, particularly in chronic injuries where the remanent ACL stump is degraded or absent. The femoral tunnel should be placed low and posterior on the lateral femoral condyle using the lateral intercondylar and bifurcate ridges as landmarks. The center of the tibial footprint can be determined by referencing the medial tibial spine and posterior border of anterior horn of lateral meniscus. Measurement of the dimensions of the native ACL and intercondylar notch is also critical for determining graft size and minimizing the risk of impingement, with a goal of reconstructing 50% to 80% of the tibial footprint area. Clinical outcome studies have demonstrated superior anteroposterior and rotatory knee stability with low surgical revision rates (reported between 3% and 5%). By adhering to the principles of anatomic ACLR, surgeons can produce an appropriately sized and located graft for the individual patient, thereby best restoring native knee kinematics and maximizing function. The aim of this infographic is to highlight essential features of anatomic ACLR techniques, which a focus on the native anatomy and surgical planning to achieve an anatomic ACLR.

Clinical outcomes of different autografts used for all-epiphyseal, partial epiphyseal or transphyseal anterior cruciate ligament reconstruction in skeletally immature patients - a systematic review

BACKGROUND

Different types of grafts can be used for anterior cruciate ligament reconstruction (ACLR). There is little published data regarding skeletally immature patients. The purpose of this systematic review was to assess the clinical outcomes and complications for different autograft types used in all-epiphyseal, transphyseal and partial epiphyseal/hybrid ACLR in skeletally immature children and adolescents.

METHODS

PubMed, Embase and Cochrane databases were systematically searched for literature regarding ACLR using hamstrings, quadriceps or bone-patellar-tendon-bone (BPTB) autografts in skeletally immature patients. Studies were included if they examined at least one of the following outcomes: graft failure, return to sport(s), growth disturbance, arthrofibrosis or patient reported outcomes and had a minimum follow-up of 1 year. Case reports, conference abstracts and studies examining allografts and extra-articular or over-the-top ACL reconstruction techniques were excluded. Graft failure rates were pooled for each graft type using the quality effects model of MetaXL. A qualitative synthesis of secondary outcomes was performed.

RESULTS

The database search identified 242 studies. In total 31 studies were included in this review, comprising of 1358 patients. Most patients (81%) were treated using hamstring autograft. The most common used surgical technique was transphyseal. The weighted, pooled failure rate for each graft type was 12% for hamstring tendon autografts, 8% for quadriceps tendon autografts and 6% for BPTB autografts. Confidence intervals were overlapping. The variability in time to graft failure was high. The qualitative analysis of the secondary outcomes showed similar results with good clinical outcomes and low complication rates across all graft types.

CONCLUSIONS

Based on this review it is not possible to determine a superior graft type for ACLR in skeletally immature. Of the included studies, the most common graft type used was the hamstring tendon. Overall, graft failure rates are low, and most studies show good clinical outcomes with high return to sports rates.

No Effect of Return to Sport Test Batteries with and without Psychological PROs on the Risk of a Second ACL Injury: A Critical Assessment of Four Different Test Batteries

Background

Patients report psychological barriers as important when returning to sport, however, psychological outcome measures are seldom included in return to sport (RTS) assessment. There is a need for clinical trials to integrate psychological patient-reported outcomes (PROs) in return to sport batteries assessing patients treated with ACL reconstruction.

Objective

The aim of this study was to determine the association between passing clinical tests of muscle function and psychological PROs and sustaining a second ACL injury in patients who RTS after primary ACL reconstruction.

Design

Retrospective Cohort study.

Methods

Patients' sex, age, height and weight, and the results of strength and hop tests, as well as answers to PRO's (including Tegner activity scale, the ACL Return to Sport after Injury scale (ACL-RSI) as well as the Quality of Life (QoL) subscale of the Knee injury and Osteoarthritis Outcome Score [KOOS]), were extracted from a rehabilitation-specific registry. Four different test batteries comprising muscle function tests and PROs were created to assess whether patients were ready to RTS. Passing each of the test batteries (yes/no) was used as an independent variable. A multivariable Cox proportional hazard model analysis was performed, with sustaining a second ACL injury (either ipsi- or contralateral; yes/no) within two years of RTS as the dependent variable.

Results

A total of 419 patients (male, n=214; 51%) were included, of which 51 (12.2%) suffered a second ACL injury within the first two years after RTS. There were no differences in passing rates in the different RTS test batteries comprising muscle function tests and PROs for patients who suffered a second ACL injury compared to patients who did not.

Conclusion

No association between passing the RTS clinical tests batteries comprising muscle function and psychological PROs used, and the risk of a second ACL injury could be found.

Level of Evidence

3©The Author(s).

Height is a predictor of hamstring tendon length and ACL graft characteristics in adolescents

BACKGROUND

Knowing the potential hamstring tendon length is relevant for planning ligament reconstructions in children and adolescents, as it is not uncommon to encounter small hamstring tendons intraoperatively. The aim of this study is to predict semitendinosus and gracilis tendon length based on anthropometric values in children and adolescents. The secondary aim is to analyse hamstring tendon autograft characteristics in a closed socket anterior cruciate ligament reconstructions and to evaluate the relationship with anthropometric variables. The hypothesis of this study was that height is predictor of hamstring tendon length and thereby graft characteristics.

METHODS

This observational study included two cohorts of adolescents undergoing ligament reconstructions between 2007-2014 and 2017-2020. Age, sex, height and weight were recorded preoperatively. Semitendinosus and gracilis tendon length and graft characteristics were measured intraoperatively. Regression analysis was performed on tendon length and anthropometric values. Subgroup analyses of the closed socket ACL reconstruction were performed and the relation between anthropometric values and graft characteristics were analysed.

RESULTS

The population consisted of 171 adolescents from 13 to 17 years of age, with a median age of 16 years [IQR 16-17]. The median semitendinosus tendon length was 29 cm [IQR 26-30] and gracilis tendon length was 27 cm [IQR 25-29]. Height was a significant predictor of semitendinosus and gracilis tendon length. Subgroup analysis of the closed socket ACL reconstructions showed that in 75% of the procedure, the semitendinosus tendon alone was sufficient to create a graft with a minimum diameter of 8.0 mm.

CONCLUSIONS

Height is a significant predictor of semitendinosus and gracilis tendon length in adolescents between 13 and 17 years of age and outcomes are similar to data in adults. In 75% of the closed socket ACL reconstructions, the semitendinosus tendon alone is sufficient to create an adequate graft with a minimum diameter of 8 mm. Additional use of the gracilis tendon is more often necessary in females and shorter patients.

LEVEL OF EVIDENCE: 3

Ceiling Effect of the Combined Norwegian and Danish Knee Ligament Registers Limits Anterior Cruciate Ligament Reconstruction Outcome Prediction

BACKGROUND

Clinical tools based on machine learning analysis now exist for outcome prediction after primary anterior cruciate ligament reconstruction (ACLR). Relying partly on data volume, the general principle is that more data may lead to improved model accuracy.

PURPOSE/HYPOTHESIS

The purpose was to apply machine learning to a combined data set from the Norwegian and Danish knee ligament registers (NKLR and DKRR, respectively), with the aim of producing an algorithm that can predict revision surgery with improved accuracy relative to a previously published model developed using only the NKLR. The hypothesis was that the additional patient data would result in an algorithm that is more accurate.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Machine learning analysis was performed on combined data from the NKLR and DKRR. The primary outcome was the probability of revision ACLR within 1, 2, and 5 years. Data were split randomly into training sets (75%) and test sets (25%). There were 4 machine learning models examined: Cox lasso, random survival forest, gradient boosting, and super learner. Concordance and calibration were calculated for all 4 models.

RESULTS

The data set included 62,955 patients in which 5% underwent a revision surgical procedure with a mean follow-up of 7.6 ± 4.5 years. The 3 nonparametric models (random survival forest, gradient boosting, and super learner) performed best, demonstrating moderate concordance (0.67 [95% CI, 0.64-0.70]), and were well calibrated at 1 and 2 years. Model performance was similar to that of the previously published model (NKLR-only model: concordance, 0.67-0.69; well calibrated).

CONCLUSION

Machine learning analysis of the combined NKLR and DKRR enabled prediction of the revision ACLR risk with moderate accuracy. However, the resulting algorithms were less user-friendly and did not demonstrate superior accuracy in comparison with the previously developed model based on patients from the NKLR alone, despite the analysis of nearly 63,000 patients. This ceiling effect suggests that simply adding more patients to current national knee ligament registers is unlikely to improve predictive capability and may prompt future changes to increase variable inclusion.

Association Between Anterior Tibial Subluxation of Lateral Compartment and High-Grade Knee Laxity in Patients With Anterior Cruciate Ligament Deficiency

BACKGROUND

High-grade knee laxity and excessive anterior tibial subluxation (ATS) are correlated with poor clinical outcomes in patients with anterior cruciate ligament (ACL) deficiency and share similar risk factors; however, the association between excessive ATS and high-grade knee laxity remains unclear.

PURPOSE

To identify the association between excessive ATS and high-grade knee laxity in patients with ACL deficiency and determine the possibility that ATS can predict high-grade knee laxity.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 226 patients who underwent ACL reconstruction between May 2018 and March 2022 were analyzed in the present study; the high-grade group consisted of 113 patients who had a grade 3 result on the preoperative anterior drawer test, Lachman test, or pivot-shift test while under anesthesia, and the low-grade group consisted of 113 matched patients. The ATS values for medial and lateral compartments (ATSMC and ATSLC) were measured on magnetic resonance imaging while patients relaxed the quadriceps in the supine position under no anesthesia. The optimal cutoff values of ATSMC and ATSLC for high-grade knee laxity were determined using receiver operating characteristic curves. Univariate and multivariate logistic regression analyses with stratification were performed to identify the association between excessive ATS and high-grade knee laxity.

RESULTS

Compared with the low-grade group, the high-grade group had a longer time from injury to surgery; higher rates of medial meniscus posterior horn tear (MMPHT), lateral meniscus posterior horn tear (LMPHT), and anterolateral ligament (ALL) abnormality; and larger lateral tibial slope, ATSMC, and ATSLC. The optimal cutoff value was 2.6 mm (sensitivity, 52.2%; specificity, 76.1%) for ATSMC and 4.5 mm (sensitivity, 67.3%; specificity, 64.6%) for ATSLC in predicting high-grade knee laxity. After adjustment for covariates, ATSLC ≥4.5 mm (odds ratio [OR], 2.94; 95% CI, 1.56-5.55; P = .001), MMPHT (OR, 2.62; 95% CI, 1.35-5.08; P = .004), LMPHT (OR, 2.39; 95% CI, 1.20-4.78; P = .014), and ALL abnormality (OR, 2.09; 95% CI, 1.13-3.89; P = .019) were associated with high-grade knee laxity. The association between excessive ATSLC and high-grade knee laxity was validated in patients with acute ACL injury as well as those with chronic ACL injury.

CONCLUSION

Excessive ATSLC was associated with high-grade knee laxity in patients who had ACL deficiency, with a predictive cutoff value of 4.5 mm. This study may help surgeons estimate the degree of knee instability more accurately before anesthesia and may facilitate preliminary surgical decision-making, such as appropriate graft choices and consideration of extra-articular augmentation.

Anatomic anterior cruciate ligament reconstruction: Freddie Fu's paradigm

Anterior cruciate ligament (ACL) reconstruction techniques have evolved over the past four decades. There is evidence that non-anatomic reconstruction techniques, such as traditional transtibial drilling, fail to recreate the native anatomy of the ACL, which can lead to increased rotatory knee instability, revision risk, and post-traumatic osteoarthritis. Anatomic ACL reconstruction has emerged as the gold standard, with the goal of restoring the patient's native anatomy and knee kinematics. This review will summarise the relevant anatomy, modern anatomic ACL reconstruction techniques, and literature supporting anatomic ACL reconstruction as the new paradigm. LEVEL OF EVIDENCE: Level V, review article.

Effect of Cross-sectional Area of the Hamstring Tendon Autograft on Failure Rate or Clinical Outcomes After Double-Bundle ACL Reconstruction: Tendon Autograft

Background

In previous studies examining the relationship between graft size and failure rate after anterior cruciate ligament reconstruction (ACLR), graft size was determined as diameter of the bone tunnel, and graft failure was defined as revision surgery. Consequently, the correlation between graft size and postoperative recurrent instability could not be assessed.

Purpose

(1) To intraoperatively measure the cross-sectional area (CSA) of the hamstring tendon (HT) autograft and compare the CSA of the autograft with the bone tunnel and (2) to assess the effect of the graft CSA on postoperative graft failure among patients who underwent double-bundle ACLR.

Study Design

Case-control study; Level of evidence, 3.

Methods

The study included 129 patients who underwent double-bundle ACLR using an HT autograft (mean ± SD age, 16.7 ± 1.7 years; all with a Tegner activity level ≥6). All patients had a minimum follow-up of 2 years. During surgery, the graft CSA was measured using an area micrometer, combining the anteromedial (AM) and posterolateral (PL) grafts. The total area of the bone tunnel was defined as the combined CSAs of the AM and PL tunnels as calculated by the diameter of the drill. The relationship between the CSAs of the combined HT graft and the bone tunnel was statistically compared, as was the relationship between graft CSAs and graft failure, defined as reinjury, recurrent instability manifested as quantitative laxity measurement, or revision ACLR.

Results

The CSAs of the midsubstance of the combined AM and PL graft significantly correlated with those of the bone tunnels (femoral side, R ² = 0.334, P < .0001; tibial side, R ² = 0.421, P < .0001). As for the relationship between the graft CSA and ACLR failure, there was no significant difference in the graft CSAs between the groups with and without graft failure in any of the failure criteria (P = .188).

Conclusion

The graft CSA was not a predictor of early failure after double-bundle ACLR using an HT autograft in this patient population.

The German Arthroscopy Registry DART: what has happened after 5 years?

PURPOSE

The German Arthroscopy Registry (DART) has been initiated in 2017 with the aim to collect real-life data of patients undergoing knee, shoulder, hip or ankle surgery. The purpose of this study was to present an overview of the current status and the collected data thus far.

METHODS

Data entered between 11/2017 and 01/2022 were analyzed. The number of cases (each case is defined as a single operation with or without concomitant procedures) entered for each joint, follow-up rates and trends between different age groups (18-29 years, 30-44 years, 45-64 years,  ≥ 65 years) and across genders, and quality of life improvement (pre- vs. 1 year postoperative EQ visual analogue scale [EQ-VAS]) for frequently performed procedures (medial meniscus repair [MMR] vs. rotator cuff repair [RCR] vs. microfracturing of the talus [MFX-T]) were investigated.

RESULTS

Overall, 6651 cases were entered into DART, forming three distinct modules classified by joint (5370 knee, 1053 shoulder and 228 ankle cases). The most commonly entered procedures were: knee: partial medial meniscectomy (n = 2089), chondroplasty (n = 1389), anterior cruicate ligament reconstruction with hamstring autograft (n = 880); shoulder: sub acromial decompression (n = 631), bursectomy (n = 385), RCR (n = 359); ankle: partial synovectomy (n = 117), tibial osteophyte resection (n = 72), loose body removal (n = 48). In the knee and shoulder modules, middle-aged patients were the predominant age group, whereas in the ankle module, the youngest age group was the most frequent one. The two oldest age groups had the highest 1-year follow-up rates across all modules. In the knee and shoulder module, 1-year follow-up rates were higher in female patients, whereas follow-up rates were higher in male patients in the ankle module. From pre- to 1-year postoperative, MFX-T (EQ-VAS: 50.0 [25-75% interquartile range: 31.8-71.5] to 75.0 [54.3-84.3]; ∆ + 25.0) led to a comparably larger improvement in quality of life than did MMR (EQ-VAS: 70.0 [50.0-80.0] to 85.0 [70.0-94.0]; ∆ + 15.0) or RCR (EQ-VAS: 67.0 [50.0-80.0] to 85.0 [70.0-95.0]; ∆ + 18.0).

CONCLUSION

DART has been sufficiently established and collects high-quality patient-related data with satisfactory follow-up allowing for a comprehensive analysis of the collected data. The current focus lies on improving patient enrolment and follow-up rates as well as initiating the hip module.

Meniscal resection increases the risk of residual knee laxity even in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction with eight strands of hamstring autografts

PURPOSE

To compare the midterm clinical outcomes of different meniscal surgeries in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction (DB-ACLR) with eight strands of hamstring (HT8) autografts and explore the potential predictive risk factors for residual knee laxity.

METHODS

From 2010 to 2017, a total of 410 patients who underwent anatomic trans-tibial DB-ACLR with HT8 autografts (169 patients without meniscal surgery, 105 patients with meniscal repair, and 136 patients with meniscal resection) were included in this study. The equivalent graft diameter was introduced to make the total graft size of DB-ACLR comparable with that of single-bundle ACLR and calculated as the square root of the quadratic sum of the diameter for each bundle. Residual laxity was defined as excessive anterior tibial translation or residual pivot shift at any follow-up visit, while graft rupture was confirmed by second-look arthroscopy or magnetic resonance imaging.

RESULTS

The mean follow-up period was 8.3 ± 2.2 years. The mean equivalent graft diameter was 9.9 ± 0.7 mm. Graft rupture was confirmed in 16 (3.9%) patients, while residual laxity was detected in 72 (17.6%) patients (34 [25.0%] in the meniscal resection group vs. 22 [13.0%] in the no meniscal surgery group, p = 0.021). In the multivariate logistic regression analysis, high-grade preoperative knee laxity (odds ratio OR 2.04, p = 0.020), equivalent graft diameter < 9 mm (OR 3.31 compared with 9-10 mm, p = 0.012; OR 3.28 compared with ≥ 10 mm, p = 0.019), and meniscal resection (OR 1.94 compared with no meniscal surgery, p = 0.045) were associated with residual laxity.

CONCLUSION

During a midterm follow-up, meniscal resection increased the risk of residual knee laxity even in patients undergoing anatomic DB-ACLR with HT8 autografts. Increasing the hamstring graft diameter and preserving the menisci are important strategies for ACLR to restore knee stability.

LEVEL OF EVIDENCE

Level III.

Changes in the Cross-Sectional Profile of Treated Anterior Cruciate Ligament Within 2 Years After Surgery

Background:

The cross-sectional area (CSA) of the anterior cruciate ligament (ACL) and reconstructed graft has direct implications on its strength and knee function. Little is known regarding how the CSA changes along the ligament length and how those changes vary between treated and native ligaments over time.

Hypothesis:

It was hypothesized that (1) the CSA of reconstructed ACLs and restored ACLs via bridge-enhanced ACL restoration (BEAR) is heterogeneous along the length. (2) Differences in CSA between treated and native ACLs decrease over time. (3) CSA of the surgically treated ACLs is correlated significantly with body size (ie, height, weight, body mass index) and knee size (ie, bicondylar and notch width).

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Magnetic resonance imaging scans of treated and contralateral knees of 98 patients (n = 33 ACL reconstruction, 65 BEAR) at 6, 12, and 24 months post-operation were used to measure the ligament CSA at 1% increments along the ACL length (tibial insertion, 0%; femoral insertion, 100%). Statistical parametric mapping was used to evaluate the differences in CSA between 6 and 24 months. Correlations between body and knee size and treated ligament CSA along its length were also assessed.

Results:

Hamstring autografts had larger CSAs than native ACLs at all time points (P < .001), with region of difference decreasing from proximal 95% of length (6 months) to proximal 77% of length (24 months). Restored ACLs had larger CSAs than native ACLs at 6 and 12 months, with larger than native CSA only along a small midsubstance region at 24 months (P < .001). Graft CSA was correlated significantly with weight (6 and 12 months), bicondylar width (all time points), and notch width (24 months). Restored ACL CSA was significantly correlated with bicondylar width (6 months) and notch width (6 and 12 months).

Conclusion:

Surgically treated ACLs remodel continuously within the first 2 years after surgery, leading to ligaments/grafts with heterogeneous CSAs along the length, similar to the native ACL. While reconstructed ACLs remained significantly larger, the restored ACL had a CSA profile comparable with that of the contralateral native ACL. In addition to size and morphology differences, there were fundamental differences in factors contributing to CSA profile between the ACL reconstruction and BEAR procedures.

Registration:

NCT 02664545 (ClinicalTrials.gov identifier).

The Use of Five-Strand Hamstring Autograft to Increase the Graft Size in Anterior Cruciate Ligament Reconstruction-A Prospective Cohort Study With Satisfactory Early Clinical Results

Objectives

To report on the outcomes of using 5-strand hamstring autograft to increase the graft size for anterior cruciate ligament (ACL) reconstruction and to determine whether the clinical results are comparable to using conventional 4-strand graft.

Methods

A prospective cohort study of patients with arthroscopic-assisted single-bundle ACL reconstruction using hamstring autograft from January 2019 to June 2021.The patients were prospectively recruited to undergo ACL reconstruction with either 5-strand hamstring graft (group A) or 4-strand hamstring graft (group B).

Results

In total, 45 patients were included into the study. The mean diameter of the final graft was 8.9 ± 0.6 cm in the 5-strand group and 7.5 ± 0.8 cm in the 4-strand group (P < .001). Four-strand graft diameter measurements were taken intraoperatively in the 5-strand group before preparation of the 5-strand graft. The mean graft diameter of the 4-strand grafts was similar in both groups: 7.3 ± 0.3 mm in group A and 7.5 ± 0.8 mm in group B (P = .72). There was no statistically significant difference between the 2 groups of patients in terms of the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS) Symptoms, KOOS Pain, KOOS Activities of Daily Living, KOOS Sports and KOOS Quality of Life scores. There were no postoperative complications of wound infection in both groups of patients. There was one case of graft rupture (4.8%) in the 4-strand group, which required revision reconstruction with patellar tendon graft 9 months postoperatively. There was no case of graft rupture in the 5-strand group (P = .29).

Conclusions

The 5-strand hamstring graft technique provides a graft with significantly larger graft diameter than the quadrupled graft technique, with satisfactory short- to medium-term outcomes. The 5-strand graft is therefore a useful technique to increase the graft size when faced with the problem of small hamstring graft.

Level of Evidence

Level II, prospective cohort study.

Joint effusion at 3 months after anterior cruciate ligament reconstruction is associated with reinjury

PURPOSE

To evaluate whether joint effusion at 3 months after anterior cruciate ligament (ACL) reconstruction is associated with ACL reinjury.

METHODS

The medical records of 227 consecutive patients who underwent single-bundle ACL reconstruction between 2015 and 2018 were reviewed in this retrospective single-center study. Demographic data such as sex and age at surgery, as well as data on preinjury Tegner activity scale score, time from injury to surgery, presence of meniscus and cartilage injuries, and the occurrence of ACL reinjury within 2 years, were collected. Joint effusion was defined as grade 3 (range 0-3) according to the ACL Osteoarthritis Score by magnetic resonance imaging at 3 months postoperatively. Multivariate logistic regression analysis was performed to control for potential confounders.

RESULTS

A total of 176 patients (mean age 22.5 ± 9.9 years) were included. Among these patients, 18 (10.2%) had ACL reinjury. At the multivariate logistic regression analysis, higher Tegner activity scale (odds ratio [OR] 3.12; 95% confidence interval [CI] 1.61-6.04; p < 0.001) and presence of joint effusion (OR 34.5; 95% CI 6.63-179.7; p < 0.001) increased the odds of ACL reinjury, and older age (OR 0.68; 95% CI 0.51-0.92; p = 0.012) decreased the odds of ACL reinjury.

CONCLUSIONS

Joint effusion with a larger fluid volume at 3 months postoperatively was one of the risk factors for ACL reinjury independent of confounders, such as age and activity level. This result suggests the possibility of postoperative intervention for ACL reinjury.

LEVEL OF EVIDENCE

III.

Scoping Review on ACL Surgery and Registry Data

Purpose of Review

To present an overview of registry-based anterior cruciate ligament (ACL) research, as well as provide insight into the future of ACL registries.

Recent Findings

During the past decades, the ACL registries have had an important role in increasing our understanding of patients with ACL injuries and their treatment. The registry data has deepened our understanding of factors that have been associated with an increased risk of sustaining an ACL injury and for evaluation of treatment factors and their impact on patient-related outcomes. Recently, registry-based ACL research using artificial intelligence (AI) and machine learning (ML) has shown potential to create clinical decision-making tools and analyzing outcomes. Thus, standardization of collected data between the registries is needed to facilitate the further collaboration between registries and to facilitate the interpretation of results and subsequently improve the possibilities for implementation of AI and ML in the registry-based research.

Summary

Several studies have been based on the current ACL registries providing an insight into the epidemiology of ACL injuries as well as outcomes following ACL reconstruction. However, the current ACL registries are facing future challenges, and thus, new methods and techniques are needed to ensure further good quality and clinical applicability of study findings based on ACL registry data.

Management of Intraoperative Graft-related Challenges in Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament reconstruction (ACLR) is one of the most frequently performed procedures in orthopaedic sports medicine. Intraoperative challenges related to graft procurement, graft preparation, and graft placement are common. Frequently encountered difficulties include insufficient graft diameter and graft-tunnel length mismatches, whereas less frequent challenges may be encountered during graft harvest and handling. This article discusses these possible complications and the strategies for their prevention and management. For successful ACLR, clinicians must be prepared to address each of these potential sources of difficulty.

Anterior Cruciate Ligament Reconstruction in 107 Competitive Wrestlers: Outcomes, Reoperations, and Return to Play at 6-Year Follow-up

Background

Wrestling is a physically demanding sport, with young athletes prone to anterior cruciate ligament (ACL) injuries. There is a paucity of data evaluating the results of ACL reconstruction (ACLR) in this cohort.

Purpose

To assess return to sport (RTS), patient-reported outcomes, reoperation rates, and graft survival after ACLR in a large cohort of competitive wrestlers at midterm follow-up.

Study Design

Case series; Level of evidence, 4.

Methods

We identified all competitive wrestlers (club, high school, collegiate, or professional) with a history of an ACLR at a single institution between 2000 and 2019. Graft failure was defined as a retear (as determined via clinical or advanced imaging evaluation) and/or revision ACLR. All patients were contacted for determination of reinjury rates; current sport status; and pain visual analog scale, International Knee Documentation Committee, and Tegner activity scores.

Results

Included were 107 knees in 103 wrestlers, with a median follow-up time of 5.9 years (interquartile range [IQR], 3.9-10.3 years). The median age was 17 years (IQR, 15-18 years), with 106 (99%) male patients, and the distribution of bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts was 64 (60%) and 43 (40%), respectively. At final follow-up, 80% of athletes were able to RTP at a median of 280 days (IQR, 212-381 days). Graft failure occurred in 14 (13%) knees at a median time of 1.8 years (IQR, 0.7-5.3 years) after the index ACLR. BTB autograft demonstrated a lower failure rate compared with HT autograft (8% vs 21%; P = .044) and was associated with better survival compared with HT autograft up to 15 years after the index ACLR (90.4% vs 76.3%; P = .030). When compared by graft diameter, HT autografts of at least 7.5 mm were not associated with a lower graft failure than BTB constructs of all sizes (P = .205).

Conclusion

Return to competitive wrestling was observed in 80% of athletes after ACLR, with 14% of wrestlers experiencing graft failure. BTB autograft was associated with better survival than HT autograft.

Low annual hospital volume of anterior cruciate ligament reconstruction is not associated with higher revision rates

PURPOSE

Surgery performed in low-volume centres has been associated with longer operating time, longer hospital stays, lower functional outcomes, and higher rates of revision surgery, complications and mortality. This has been reported consistently in the arthroplasty literature, but there is a paucity of data regarding the relationship between surgical volume and outcome following anterior cruciate ligament (ACL) reconstruction. The purpose was to compare ACL reconstruction failure rates between hospitals performing different annual surgical volumes.

METHODS

All patients from the Norwegian Knee Ligament Register having primary autograft ACL reconstruction between 2004 and 2016 were included. Hospital volume was divided into quintiles based on the number of ACL reconstructions performed annually, defined arbitrarily as: 1-12 (V1), 13-24 (V2), 25-49 (V3), 50-99 (V4) and ≥ 100 (V5) annual procedures. Kaplan-Meier estimated survival curves and survival percentages were calculated with revision ACL reconstruction as the end point. Secondary outcome measures included (1) mean change in Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QoL) and Sport subsections from pre-operative to 5-year follow-up and (2) subjective failure defined as KOOS QoL < 44.

RESULTS

Twenty thousand eight hundred and fifty patients met the inclusion criteria and 1195 (5.7%) underwent subsequent revision ACL reconstruction over the study period. Revision rates were lower in the lower volume hospitals compared with the higher volume hospitals (p < 0.001). There was no clinically significant difference in improvement between pre-operative and 5-year follow-up KOOS scores between hospital volume categories, but a higher proportion of patients having surgery at lower volume hospitals reported a subjective failure. Patients in the lower volume categories (V1-3) were more often male and older compared to the higher volume hospitals (V4-5). Concomitant meniscal injuries and participation in pivoting sports were most common in V5 compared with V1 (p < 0.001). Median operative time decreased as hospital volume increased, ranging from 90 min at V1 hospitals to 56 min at V5 hospitals (p < 0.001).

CONCLUSION

Patients having ACL reconstruction at lower volume hospitals had a lower rate of subsequent revision surgery relative to higher volume hospitals. However, complications occurred more frequently, operative duration was longer, and the number of patients reporting a subjective failure of ACL reconstruction was highest at these lower volume hospitals.

LEVEL OF EVIDENCE

Level III.

Dimensions of the anterior cruciate ligament and thickness of the distal femoral growth plate in children: a MRI-based study

BACKGROUND

When determining the dimensions of an anterior cruciate ligament (ACL) graft in children, bone age should be considered in addition to the patient's age, gender, and body height.

OBJECTIVES

We aimed to determine the relationship between age, gender, and ACL dimensions as well as thickness of growth plate cartilage of the distal femur during puberty.

METHODS

We retrospectively analyzed MRI scans of the knee in 131 children (82 girls, 49 boys) aged 6-18 years (mean age: 14.9 ± 2.6 years). ACL length and width as well as thickness of the growth plate cartilage at the distal femoral epiphysis were measured.

RESULTS

Mean ACL length increased linearly up to the age of 12 years in females and 14 years in males; thereafter, mean ACL length remained constant. Mean ACL length was largest at the age of 12 to < 13 years (38.18 mm) in females and at 15 to < 16 years (39.38 mm) in males. Mean ACL width increased up to the age of 12 years in girls and 13 years in boys. After the age of 12 years, both the ACL length and width were significantly larger in boys than girls (p = 0.002 and p = 0.045, respectively). Mean thickness of the growth plate cartilage of the distal femur remained stable up to the age of 12 years in girls and 14 years in boys. Thickness of the growth plate cartilage changed most markedly between the age intervals of 11 to < 12 years and 12 to < 13 years in girls and between the age intervals of 13 to < 14 years and 14 to < 15 years in boys.

CONCLUSIONS

ACL dimensions depended on both age and gender during the growth period. Measurement of cartilage thickness of the femoral distal growth plate proved to be an objective parameter to assess the maturation stage of local bone. This may be useful for the planning and timing of orthopedic ACL procedures.

LEVEL OF EVIDENCE

III-retrospective cohort study.

Suspensory Versus Interference Tibial Fixation of Hamstring Tendon Autografts in Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

BACKGROUND

The hamstring tendon is frequently used to reconstruct the anterior cruciate ligament (ACL), but there is a lack of consensus on the optimal method of fixation. Registry studies have shown that the type of femoral fixation device can influence the risk of revision ACL reconstruction (ACLR), but it is unclear whether the type of tibial fixation has an effect. In New Zealand, over 95% of hamstring tendon grafts are fixed with an adjustable loop suspensory device on the femoral side, with variable usage between suspensory and interference devices, with or without a sheath, on the tibial side.

PURPOSE

To investigate the association between the type of tibial fixation device and the risk of revision ACLR.

STUDY DESIGN

Cohort Study; Level of evidence, 2.

METHODS

Prospective data recorded in the New Zealand ACL Registry were analyzed. Only primary ACLRs performed with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. A Cox regression survival analysis with adjustment for patient factors was performed to analyze the effects of the type of tibial fixation device, the number of graft strands, and graft diameter on the risk of revision.

RESULTS

A total of 6145 primary ACLRs performed between 2014 and 2019 were analyzed. A total of 59.6% of hamstring tendon autografts were fixed with a suspensory device on the tibial side (n = 3662), 17.6% with an interference screw with a sheath (n = 1079), and 22.8% with an interference screw without a sheath (n = 1404). When compared with suspensory devices, a higher revision risk was observed when using an interference screw with a sheath (adjusted hazard ratio [HR], 2.05; P = .009) and without a sheath (adjusted HR, 1.81; P = .044). The number of graft strands and a graft diameter of ≥8 mm were associated with the rate of revision on the univariate analysis; however, after adjusting for confounding variables on the multivariate analysis, they did not significantly influence the risk of revision.

CONCLUSION

In this study of hamstring tendon autografts fixed with an adjustable loop suspensory device on the femoral side during primary ACLR, the use of an interference screw, with or without a sheath, on the tibial side resulted in a higher revision rate when compared with a suspensory device.

Anterior Cruciate Ligament Length in Pediatric Populations: An MRI Study

Background:

As regards anterior cruciate ligament (ACL) reconstruction (ACLR), graft diameter has been identified as a major predictor of failure in skeletally mature patients; however, this topic has not been well-studied in the higher risk pediatric population. Hamstring tendon autograft configuration can be adjusted to increase graft diameter, but tendon length must be adequate for ACLR. Historical parameters of expected tendon length have been variable, and no study has quantified pediatric ACL morphology with other osseous parameters.

Purpose:

To develop magnetic resonance imaging (MRI)–derived predictors of native ACL graft length in pediatric patients so as to enhance preoperative planning for graft preparation in this skeletally immature patient population.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

MRI scans of 110 patients were included (64 girls, 46 boys; median age, 10 years; range, 1-13 years). Patients with musculoskeletal diseases or prior knee injuries were excluded. The following measurements were taken on MRI: ACL length; sagittal and coronal ACL inclination; intercondylar notch width and inclination; and femoral condyle depth and width. Associations between these measurements and patient sex and age were investigated. Univariate linear regression and multivariable regression models were created for each radiographic ACL measure to compare R².

Results:

Female ACL length was most strongly associated with the depth of the lateral femoral condyle as viewed in the sagittal plane (R² = 0.65; P < .001). Other statistically significant covariates of interest included distal femoral condylar width, age, and coronal notch width (P < .05). For males, the ACL length was most strongly associated with the distal femoral condyle width as viewed in the coronal plane (R² = 0.70; P < .001). Other statistically significant covariates of interest for male ACL lengths were lateral femoral condyle depth, age, and coronal notch width (P < .05).

Conclusion:

In pediatric populations, femoral condylar depth/width and patient age may be valuable in assessing ACL size and determining appropriate graft dimensions and configuration for ACLRs. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in this high-risk group.

Reinjury Rates in Adolescent Patients 2 Years Following ACL Reconstruction

BACKGROUND

Sports injuries have increased dramatically in the pediatric and adolescent population. Return-to-sport testing and criteria are increasingly utilized, however, the guidelines for return to play in adolescents are unclear. The purpose of this study was to compare strength and function at the time of the return-to-sport progression to those with and without a failed anterior cruciate ligament reconstruction (ACLR).

METHODS

A total of 105 adolescent patients with primary ACLR were assessed at the time of return to sport. We identified graft failures/contralateral injury through medical records, clinic visits, or phone interviews at minimum 2 years of postsurgical follow-up. All patients completed bilateral isokinetic strength tests of the knee extensor/flexor groups and hop tests. Strength was expressed as torque-normalized-to-mass (Nm/kg), and limb-symmetry-index was expressed as a percentage of the uninvolved limb's strength. All patients completed outcome surveys. The χ2 analysis was used to compare failures between sexes and graft types. Independent sample t tests were used to compare knee extensor/flexor strength, symmetry, and hop test results between patients with and without secondary anterior cruciate ligament (ACL) injury. One-way analysis of variance was used to compare knee extensor/flexor strength and symmetry, hop test, and survey results between those (1) without secondary injury, (2) ACLR graft failure, and (3) contralateral ACL injury.

RESULTS

A total of 100 of 105 patients (95.2%) were included with 4±1.2 years of follow-up, with 28 (28%) sustaining subsequent injury (12% graft, 16% contralateral). Patients with graft failure demonstrated (1) stronger quadriceps strength (2.00±0.46 Nm/kg) compared with those with contralateral ACL injury (1.58±0.35 Nm/kg, P=0.039) and patients that did not have a secondary injury (1.58±0.44 Nm/kg, P=0.007), (2) greater quadriceps strength symmetry (85.7±0.11.2%) compared with patients without secondary injury ACL (72.9±17.9%, P=0.046), (3) a greater proportion of hamstring grafts compared with those without reinjury (P=0.028).

CONCLUSIONS

Adolescent patients who sustained ACLR graft failure had greater and more symmetric quadriceps strength at the time of return to sport compared with patients with no secondary injury. Objective measures of quadriceps strength at the time of the return-to-sport progression may not solely identify individuals that have a secondary ACL injury.

STUDY DESIGN

Level IV-retrospective cohort study.

Current trends in the anterior cruciate ligament part II: evaluation, surgical technique, prevention, and rehabilitation

Clinical evaluation and management of anterior cruciate ligament (ACL) injury is one of the most widely researched topics in orthopedic sports medicine, giving providers ample data on which to base their practices. The ACL is also the most commonly treated knee ligament. This study reports on current topics and research in clinical management of ACL injury, starting with evaluation, operative versus nonoperative management, and considerations in unique populations. Discussion of graft selection and associated procedures follows. Areas of uncertainty, rehabilitation, and prevention are the final topics before a reflection on the current state of ACL research and clinical management of ACL injury. Level of evidence V.

Hamstring graft diameter above 7 mm has a lower risk of failure following anterior cruciate ligament reconstruction

PURPOSE

Multi-stranded hamstring-tendon autografts have been widely used for anterior cruciate ligament reconstruction (ACLR) surgeries. Recently, smaller diameter hamstring autografts have been linked with the risk of failure or graft rupture. However, there is limited evidence concerning the optimal diameter of the hamstring autografts for ACLR. The current systematic review and meta-analysis analysed the association of ACLR failure with the diameter of hamstring autografts.

METHODS

A systematic search of three major scientific databases (Pubmed, EMBASE, and Cochrane library) was conducted to identify studies that presented ACLR failure-related outcomes with different diameters of hamstring autografts. The pooled data from the included studies were analysed to investigate the association between ACLR failure and the cut-off diameters of 6, 7, 8, and 9 mm. Subgroup analyses based on the level of evidence and follow-up duration were also performed at each cut-off diameter.

RESULTS

Of the 2282 studies screened, 16 reported failure rates with hamstring autografts of different diameters, 15 of which were included in the meta-analysis. A graft diameter ≥ 7 mm was associated with significantly lower ACLR failure rates than a graft diameter < 7 mm (p = 0.005), based on pooled data of 19,799 cases. Age < 20 years and higher physical activity were associated with significantly higher ACLR failure rates.

CONCLUSION

The current systematic review suggests that the hamstring graft diameter for ACLR should be more than 7 mm considering the significantly higher failure rates with graft diameters less than 7 mm.

LEVEL OF EVIDENCE

Level IV.

Long-term evaluation of pediatric ACL reconstruction: high risk of further surgery but a restrictive postoperative management was related to a lower revision rate

INTRODUCTION

The guidelines regarding rehabilitation after pediatric anterior cruciate ligament reconstruction (ACLR) are sparse. The aim of the study was to retrospectively describe the long-term outcome regarding further surgery and with special emphasis on the revision rate after two different postoperative rehabilitation programs following pediatric ACLR.

MATERIAL AND METHODS

193 consecutive patients < 15 years of age who had undergone ACLR at two centers, A (n = 116) and B (n = 77), in 2006-2010 were identified. Postoperative rehabilitation protocol at A: a brace locked in 30° of flexion with partial weight bearing for 3 weeks followed by another 3 weeks in the brace with limited range of motion 10°-90° and full weight bearing; return to sports after a minimum of 9 months. B: immediate free range of motion and weight bearing as tolerated; return to sports after a minimum of 6 months. The mean follow-up time was 6.9 (range 5-9) years. The mean age at ACLR was 13.2 years (range 7-14) years. The primary outcome measurement in the statistical analysis was the occurrence of revision. Multivariable logistic regression analysis was performed to investigate five potential risk factors: surgical center, sex, age at ACLR, time from injury to ACLR and graft diameter.

RESULTS

Thirty-three percent had further surgery in the operated knee including a revision rate of 12%. Twelve percent underwent ACLR in the contralateral knee. The only significant variable in the statistical analysis according to the multivariable logistic regression analysis was surgical center (p = 0.019). Eight percent of the patients at center A and 19% of the patients at B underwent ACL revision.

CONCLUSIONS

Further surgery in the operated knee could be expected in one third of the cases including a revision rate of 12%. The study also disclosed a similar rate of contralateral ACLR at 12%. The revision rate following pediatric ACLR was lower in a center which applied a more restrictive rehabilitation protocol.

LEVEL OF EVIDENCE

Case-control study, Level III.

Editorial Commentary: Large-Diameter Quadrupled Hamstring Autografts Are an Acceptable Option for National Collegiate Athletic Association Division I College Football Players: We Must Challenge Our Comfort Zone to Be Successful in the End Zone

The majority of surgeons caring for elite American football teams choose bone-patellar tendon-bone (BTB) autograft for anterior cruciate ligament reconstruction. As we strive to continue to improve currently favorable outcomes, we need to consider all options regarding graft choice, surgical technique, and postoperative rehabilitation. Advantages of BTB include an excellent track record, potential for faster incorporation with bone-to-bone healing. Disadvantages include risk of patellar fracture/tendon rupture and anterior knee pain. The pros of quadrupled hamstring (QH) graft include stronger graft (higher ultimate load to failure) and less anterior knee pain and stiffness, and the cons include loss of flexion/hamstring strength and slower healing in the tunnels. Several studies have shown that smaller grafts have higher failure rates, and recent research shows that QH grafts >9 mm had decreased risk of revision compared to BTB. We can now quadruple the semitendinosus tendon to provide elite athletes with even more robust grafts. Large-diameter QH autografts are an acceptable option for National Collegiate Athletic Association Division I college football players.

High Return to Play and Low Reinjury Rates in National Collegiate Athletic Association Division I Football Players Following Anterior Cruciate Ligament Reconstruction Using Quadrupled Hamstring Autograft

PURPOSE

The purpose of this study was to examine the outcomes of anterior cruciate ligament (ACL) reconstruction using quadrupled hamstring (QH) autograft in a cohort of National Collegiate Athletic Association (NCAA) Division I football players.

METHODS

A retrospective analysis was performed on NCAA Division I football players at a single institution who had transtibial ACL reconstruction using QH autograft between 2001 and 2016. Primary outcomes were ACL reinjury and return to play (RTP). Secondary outcomes were position, percent of eligibility used after surgery, graft diameter, Tegner-Lysholm scores, concomitant injuries/surgeries, and postcollegiate professional play.

RESULTS

Between 2001 and 2016, 34 players had QH autograft ACL reconstruction, and 29 players achieved RTP. Of the 29, 2 (6.9%) sustained ACL reinjuries. The average RTP was 318 days (range 115-628) after surgery. Players used 79.5% of their remaining collegiate eligibility after surgery. Nine players sustained multiligamentous knee injuries. This did not have a significant effect on RTP (P = 0.709; mean 306±24 days for isolated ACL, mean of 353±51 for 2 ligaments, mean of 324±114 for 3 + ligaments) and none sustained reinjury. Associated meniscal injuries were sustained by 28, and 8 sustained chondral injuries. The mean postoperative Tegner-Lysholm score was 90.7 of 100, with mean follow-up of 102 months. Of these players, 18 went on to play professionally, with 17 joining National Football League rosters and 1 an arena team roster.

CONCLUSION

QH demonstrated an ACL reinjury and RTP rates similar to those in previously published, predominantly bone-patella tendon-bone ACL reinjury data in elite athletes. This study demonstrates that QH autograft may be a viable option in elite athletes.

LEVEL OF EVIDENCE

IV, case series.

Transportal versus all-inside techniques of anterior cruciate ligament reconstruction: a systematic review

Background

Transportal (TP) and all-inside techniques (AIT) are the most commonly used anterior cruciate ligament (ACL) reconstruction procedures in current clinical practice. However, there is an ongoing debate over which procedure is superior. Therefore, the purpose of this systematic review was to evaluate and compare the clinical outcomes and complications of these two techniques to propose recommendations for future application. Our primary hypothesis was that AIT is a superior ACLR technique compared to TP.

Methods

A systematic literature review, using PRISMA guidelines, was conducted using PubMed, Medline, Google Scholar, and EMBASE, up to February 2021 to identify studies focusing on AIT and TP techniques of ACL reconstruction. We excluded animal experiments, cadaveric studies, retrospective studies, case reports, technical notes, and studies without quantitative data. Patients’ characteristics, surgical technical features, along with postoperative follow-up and complications were extracted and reported accordingly. Methodological quality of the included studies was assessed using the Modified Coleman Methodology Score (MCMS).

Results

A total of 44 studies were selected for this review, of which four were comparative studies. A total of 923 patients underwent AIT and 1678 patients underwent the TP technique for ACLR. A single semitendinosus graft was commonly used in the AIT compard to combined semitendinosus and gracilis graft in the TP group. The postoperative increase in International Knee Documentation Committee (IKDC), Lysholm, KT-1000, and Short Form-12 (physical and mental) scores were similar in the AIT group and the TP group. Contrastingly, the VAS pain score was significantly lower in the AIT group compared to the TP group. Furthermore, the pooled complication rates from all studies were similar between the two groups (AIT: 54 patients, 8.26% vs. PT: 55 patients, 6.62%). However, the four studies that prospectively compared AIT and TP techniques showed lesser complications in the AIT group than the TP group.

Conclusion

Since the future trend in orthopedic surgery is toward less invasive and patients’ satisfaction with good outcomes, AIT is a good alternative method considering preserving bony tissue and gracilis tendon with less post-operative pain, along with more knee flexor strength and equal outcomes compared to conventional ACL reconstruction surgery.

Level of Evidence II.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02872-x.

High Risk of New Knee Injuries in Female Soccer Players After Primary Anterior Cruciate Ligament Reconstruction at 5- to 10-Year Follow-up

BACKGROUND

A new anterior cruciate ligament (ACL) injury after ACL reconstruction is a feared outcome.

PURPOSE

To study the risk of new knee injuries in female soccer players 5 to 10 years after primary unilateral ACL reconstruction and to compare players who returned to soccer with (1) players who did not return and (2) knee-healthy soccer players (controls).

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Demographic, soccer-specific, and surgical data were recorded at baseline for 317 female soccer players (mean ± SD age, 20.1 ± 2.7 years) 1.6 ± 0.7 years after ACL reconstruction and for 119 matched controls (mean age, 19.5 ± 2.5 years). Data on new knee injuries and soccer-playing status were collected 5 to 10 years after ACL reconstruction via a questionnaire.

RESULTS

Among players with ACL reconstruction, 222 (70%) responded at a mean 6.5 ± 1.0 years after primary ACL reconstruction. We compared 3 cohorts: (1) among 163 players with ACL reconstruction who returned to soccer, 68 (42%) sustained 44 reruptures and 29 contralateral ruptures; (2) among 59 players with ACL reconstruction who did not return to soccer, 11 (19%) sustained 9 reruptures and 2 contralateral ruptures; and (3) among 113 knee-healthy controls, 12 (11%) sustained 13 ACL injuries. Players who returned had a >2-fold higher risk of a new ACL injury than players who did not return (risk ratio, 2.24; 95% CI, 1.27-3.93; P = .005) and a 4-fold higher risk than controls (risk ratio, 3.93; 95% CI, 2.23-6.91; P <.001). A new ACL, meniscal, or cartilage injury was the most frequent new knee injury. Among players who returned to soccer, 68% reported a new knee injury, and they had a 2- to 5-times higher risk of any new knee injury and knee surgery than players who did not return and controls.

CONCLUSION

Two-thirds of female soccer players with ACL reconstruction who returned to soccer sustained a new knee injury within 5 to 10 years; 42% had a new ACL injury. Their risk of a new knee injury and knee surgery was 2 to 5 times greater than that for players who did not return and for knee-healthy controls. New injury may have negative consequences for long-term knee health and should be a critical consideration in the decision to return to play.

Current concepts in graft selection for anterior cruciate ligament reconstruction

Graft selection for anterior cruciate ligament reconstruction (ACLR) is important for optimizing post-operative rehabilitation, facilitating return to full sporting function and reducing the risk of complications.The most commonly used grafts for ACLR include hamstring tendon autografts, bone-patellar tendon-bone autografts, quadriceps tendon autografts, allografts and synthetic grafts.This instructional review explores the existing literature on clinical outcomes with these different graft types for ACLR and provides an evidence-based approach for graft selection in ACLR.The existing evidence on the use of extra-articular tenodesis to provide additional rotational stability during ACLR is also revisited. Cite this article: EFORT Open Rev 2021;6:808-815. DOI: 10.1302/2058-5241.6.210023.

Editorial Commentary: With Appropriate Anterior Cruciate Ligament Graft Selection, All-Inside Reconstruction Results in Excellent Outcomes: Stay "Inside" and Be Cognizant of Hamstring Graft Diameter Expectations in Shorter Patients

All-inside anterior cruciate ligament (ACL) reconstruction is a minimally invasive and anatomic technique with predictably excellent results. The array of graft choices that exists for skilled arthroscopists include semitendinosis autograft with or without gracilis, quadriceps tendon autograft, and patellar tendon autograft and allograft. The advantages of all-inside ACL reconstruction include independent femoral socket creation and less pain compared with a full tibial tunnel in the early postoperative period. This is a technique that should not trump appropriate graft selection. It is expected that autografts will fare better in younger patients who participate in activities at greater risk for ACL injuries. Selection of a semitendinosis autograft results in predictably excellent results when graft diameters are 8 mm or greater. Quadrupling the semitendinosis and adding the gracilis when needed can provide sufficient graft diameter in many patients. However, caution should be taken when harvesting hamstring grafts from shorter patients. Semitendinosis tendons in such patients are sometimes not long enough to quadruple and can result in a diameters less than 8 mm even when the gracilis is added. With appropriate graft selection, staying "inside" for ACL reconstruction is expected to result in great objective and subjective outcomes for our patients.