Anterior Cruciate Ligament Tear

Risk factors for patellofemoral joint osteoarthritis following ACL reconstruction: A cluster analysis of anatomy and alignment

Individuals who undergo anterior cruciate ligament reconstruction are at elevated risk for developing early-onset patellofemoral joint osteoarthritis. Our objective was to use K-means clustering to ascertain whether individuals at risk for patellofemoral joint osteoarthritis could be identified as determined by the presence of multiple co-existing anatomical and patella alignment risk factors. Forty participants (20 after anterior cruciate ligament reconstruction, 20 healthy controls) underwent magnetic resonance imaging assessment of the patellofemoral joint. Measures of hypothesized risk factors for patellofemoral joint osteoarthritis were obtained including patella alignment (lateral patella displacement and tilt), trochlear morphology (sulcus angle, lateral inclination angle), patella height (Insall-Salvati ratio and patella articulating overlap), and patellofemoral joint contact area. K-means clustering (k = 2) was used to ascertain whether a high-risk group could be identified. Following clustering, two distinct groups were detected. Participants assigned to cluster 1 exhibited features consistent with patellofemoral joint osteoarthritis including greater lateral patellar displacement and tilt, flatter trochlear grooves and lower lateral trochlear inclination, less patella articulating overlap, and reduced contact area. The proportion of females after anterior cruciate ligament reconstruction assigned to cluster 1 was 75% (N = 15) compared to 25% of healthy females (N = 5). K-means clustering was capable of characterizing individuals at elevated risk for patellofemoral joint osteoarthritis based on the presence of multiple co-existing anatomical and patella alignment risk factors. The fact that a significant percentage of females were assigned to the high-risk cluster supports the clinical observation that these individuals may be at higher risk of early-onset patellofemoral joint osteoarthritis.

Patients with ACL injury have lower and more posterior position of proximal tibiofibular joint than patients with intact ACL

BACKGROUND

Knees with anterior cruciate ligament (ACL) injury have distinct knee bone morphology. However, the correlation between ACL injury and morphology of the proximal tibiofibular joint has not been investigated.

PURPOSE

To compare proximal tibiofibular joint morphology in patients with injured and intact ACLs to aid in predicting and preventing ACL injuries.

MATERIAL AND METHODS

A total of 50 patients with ACL injury and 50 individuals without structural knee damage (revealed by magnetic resonance imaging [MRI]) were included in this study. In the anteroposterior knee radiographs, the length between the proximal end of the fibular head and the medial and lateral tibia joint line were measured. In the axial knee MRI scans with the most proximal part of the fibular head, the distance calculation was performed between the most anterior point of the tibia plateau (MATP) and the most anterior point of fibular head (MAFH).

RESULTS

The mean length from the proximal end of the fibular head and the medial and lateral tibial joint lines was 8.7 ± 2.8 mm and 13.2 ± 2.6 mm in the ACL-injured group, and 6.5 ± 2.8 mm and 11.1 ± 2.4 mm in the control group. The length for both medial and lateral sides was significantly greater in the ACL-injured group. The length between the MATP and MAFH was significantly larger in the ACL-injured group than the control group.

CONCLUSION

A large distance between the proximal end of the fibular head and the tibial joint line and knees with posterior fibular head placement would be another anatomic risk factor of ACL injury.

Association of tibial slope alterations with anterior cruciate ligament (ACL) injury and mucoid degeneration

OBJECTIVE

To compare radiographic measurements of lateral tibial slope (LTS), medial TS (MTS), and coronal TS (CTS) in MRI-defined intact, injured, and mucoid-degenerated native ACL knees and determine inter-reader reliability.

MATERIALS AND METHODS

Patient records from 2 years at tertiary care hospitals were reviewed for individuals aged 18-100 undergoing 3-Tesla knee MRI and radiographs. Two randomly selected cohorts, control, and pathologic ACLs on MRI with 86 patients each, were age, gender, and BMI-matched. A fellowship-trained musculoskeletal radiologist reevaluated curated images, characterizing ACL status. Two trained medical students independently collected clinical data and measured slopes on blinded radiographs. ICC, Cohen's kappa, and case-control matching were performed using SPSS statistical package, with ICC and ANOVA used for comparisons.

RESULTS

Among 172 patients with 172 MRIs and radiographs, there were 86 controls and 86 ACL lesions. There were 108/172 (62.79%) males and 64/172 (37.21%) females. ICCs were 0.966 for MTS, 0.975 for LTS, and 0.978 for CTS. Mucoid degeneration patients had a higher BMI and were older than control (p < .05) or completely torn (p < .001) ACL patients. There was no difference in TS between normal and pathologic ACLs; however, LTS-MTS differences were larger with partial tears (2.5 ± 4.9) than normal ACLs by 4.5° (± 1.2, p < .001), complete tears by 4.5° (± 1.3, p < .001), and mucoid degeneration by 4.9° (± 1.5, p = .001).

CONCLUSION

Various TS measurements are reliable. LTS-MTS differences are associated with different ACL lesions compared to normal ACLs.

Subjective grade of apprehension during the pivot-shift test reflects patient-reported outcomes more than conventional pivot-shift test grade after ACL reconstruction

PURPOSE

To investigate whether the pivot-shift test reflects patient-reported outcomes 1 year after anterior cruciate ligament (ACL) reconstruction based on a multicentre prospective cohort study.

METHODS

This study included patients who underwent primary ACL reconstruction using the hamstring tendons. The pivot-shift test grades were determined according to the International Knee Documentation Committee (IKDC) form as 0, 1+, 2+ or 3+. In addition, patients' subjective apprehension during the pivot-shift test were classified as 0 (no-apprehension), 1+ (mild-apprehension), 2+ (moderate-apprehension) or 3+ (severe-apprehension). In this study, a positive pivot-shift test was defined as grade 1+ or higher.

RESULTS

A total of 837 patients were enroled in this study. One year postoperatively, there was no significant difference in the Knee injury and Osteoarthritis Outcome Score (KOOS), IKDC score, Lysholm knee scale and Tegner activity scale between the positive (118 patients) and negative (719 patients) groups of the conventional IKDC grading of the pivot-shift test. However, when divided into two groups based on the apprehension grading of the pivot-shift test after surgery, the postoperative scores were significantly lower in the apprehension-positive group (114 patients) than those in the apprehension-negative group (723 patients) on the Tegner activity scale and KOOS Symptom, Sports/Rec and Quality of Life subscales.

CONCLUSIONS

Patients' subjective apprehension during the pivot-shift test after ACL reconstruction was significantly associated with the postoperative Tegner activity scale and three subscales of the KOOS. However, there was no association between the conventional IKDC grading of the pivot-shift test and any patient-reported outcomes postoperatively.

LEVEL OF EVIDENCE

Level II.

Quadriceps-Strength-Testing Practices and Barriers During Return to Sport After ACL Reconstruction: A Survey of College Athletic Trainers

CONTEXT

Quadriceps strength is a key outcome for guiding rehabilitation and return to sport-specific activities after anterior cruciate ligament reconstruction (ACLR) surgery.

OBJECTIVE

(1) Describe the quadriceps-strength-testing practices and barriers college athletic trainers (ATs) are using and experiencing when returning patients to sport-specific activities after ACLR. (2) Compare testing methods between college ATs working in the National Collegiate Athletic Association (NCAA) Division I setting and other college settings.

DESIGN

Cross-sectional study.

SETTING

Online survey.

PATIENTS OR OTHER PARTICIPANTS

Two hundred forty-three full-time collegiate ATs who had primarily overseen/directed an ACLR rehabilitation in the past 5 years (age = 34.8 ± 10.7 years, length of AT practice = 11.7 ± 9.3 years, NCAA Division I setting = 56%).

MAIN OUTCOME MEASURE(S)

Our survey included 4 sections: demographics, general ACLR rehabilitation practices, quadriceps-strength-testing methods and criteria, and quadriceps-strength-testing barriers.

RESULTS

Knee-muscle strength was the most common (98%) outcome collegiate ATs used when determining whether an ACLR patient is ready to progress to sport-specific activities. Manual muscle testing was the most used testing method (57%), followed by isokinetic dynamometry (IKD) (48%), repetition maximum testing (35%) and handheld dynamometry (22%). Most ATs (63%-64%) used greater than 90% side-to-side symmetry as their return to sport-specific activities criterion. Lack of equipment needed (83%), lack of financial means (28%), and lack of training/education (20%) were the barriers that most limited ATs use of IKD testing, the gold standard testing method. Compared with ATs in other settings, a greater proportion of ATs working in the NCAA Division I setting used IKD testing (65% vs 28%) and a smaller proportion used manual muscle testing (47% vs 70%).

CONCLUSIONS

Although almost all college ATs considered knee-muscle strength an important outcome to assess when returning patients to sport-specific activities after ACLR, quadriceps-strength-testing practices were highly variable among ATs and may be affected by access to necessary resources.

tRNA-derived fragment 3031B regulates human anterior cruciate ligament cell proliferation and survival by targeting RELA

tRNA-derived fragments (tRFs) are novel short noncoding RNAs that play pivotal roles in cell proliferation and survival. However, knowledge of the biological roles of tRFs in anterior cruciate ligament (ACL) cells is limited. Here, we intended to investigate the function of tRF-3031B in ACL cell. We used the tRF and tiRNA array to analyze tRF and tiRNA expression profiles in osteoarthritis (OA) ACL cells and normal ACL cells, and qRT-PCR and fluorescence in situ hybridization (FISH) were used to determine tRF-3031B expression. The results showed that tRF-3031B was expressed at low levels in OA ACL and Interleukin-1β (IL-1β) treated ACL cells. We found that RELA was the target of tRF-3031B. When ACL cells were transfected with tRF-3031B mimics, RELA expression was suppressed, whereas transfection with tRF-3031B inhibitors had the opposite effect. The rescue and dual-luciferase reporter assays showed that tRF-3031B silenced the RELA expression by binding to its untranslated region (3'-UTR). Hence, this study showed the novel function of tRF-3031B in regulating ACL cell proliferation and survival by targeting RELA, and these findings may offer a new direction for the study of ACL degeneration and pathophysiological of OA.

Effect of knee extension constraint training on walking biomechanics 6 months after anterior cruciate ligament reconstruction: a double-blind randomized controlled clinical trial

BACKGROUND

The incidence of knee osteoarthritis after anterior cruciate ligament reconstruction (ACLR) is high to 57%, and the biomechanical abnormality during walking is one of the reasons. The purpose of this study was to investigate the effect of 12 weeks of knee extension constraint training on walking biomechanics during the stance phase of injured side after ACLR.

METHODS

Forty-five patients were randomly assigned to three groups based on different brace conditions from 13 weeks to 24 weeks after ACLR: experimental (brace with knee extension constraint), placebo (brace without knee extension constraint), and control (no brace). Gait analysis was performed 3 and 6 months after ACLR. The peak for knee flexion angle (KFA), knee extension moment (KEM), and vertical ground reaction force (vGRF) were compared by 2 (time) x 3 (group) repeated-measures analysis of covariance (ANCOVA), and pairwise comparisons were conducted. .

RESULTS

There was a significant time x group interaction for the peak KFA (p = 0.047), and there was no significant time x group interaction for the peak KEM and peak vGRF. The pairwise comparisons showed that there were no statistical differences among the groups both the pre-intervention and post-intervention in the peak KFA, peak KEM, and peak vGRF. Compared with pre-intervention, the peak vGRF in the experimental group was significantly greater (p = 0.009) and the peak KFA in the control group was significantly lower (p = 0.041) post-intervention. There were not significantly different in the placebo group between pre-intervention and post-intervention.

CONCLUSION

12 weeks of knee extension constraint training can increase lower extremity loading on the injured side, may be a potential therapeutic adjunct to improve abnormal gait after ACLR.

Return to Sport Following Anterior Cruciate Ligament Reconstruction: A Scoping Review of Criteria Determining Return to Sport Readiness

PURPOSE OF REVIEW

Provide a concise review of currently utilized functional metrics and patient reported outcomes measures (PROMs) determining appropriate return to sport following anterior cruciate ligament reconstruction (ACLR).

RECENT FINDINGS

When determining return to sport following ACLR, a limb symmetry index (LSI) ≥ 90% when compared to the contralateral extremity is the most commonly reported functional metric. LSI is most commonly assessed using isokinetic quadriceps strength, followed by single-leg vertical hop and cross-over hop test. A minimum ACL-Return to Sport Index (ACL-RSI) score of 68.2 was reported, as well as a mean International Knee Documentation Committee (IKDC) score of 88.3%. A minimum Knee Injury and Osteoarthritis Outcome Score-Quality of Life (KOOS-QoL) of 62.5% was reported in a single investigation. There remains limited data on reported metrics guiding return to sport following ACLR. Evaluation of LSI when compared to the contralateral extremity is the most commonly reported functional measure, with ACL-RSI, IKDC and KOOS-QoL also being reported. Further investigations examining return to sport rate and the incidence of recurrent injury, factoring in differences in sex, competition level, and the presence or absence of concomitant meniscal injuries, based on functional metrics and PROMs is warranted to better understand which outcome measures are predictive of successful return to sport following ACLR.

Biological augmentation of anterior cruciate ligament reconstruction with bone marrow aspirate concentrate: a systematic review and meta-analysis of randomised controlled trials

PURPOSE

Biological augmentation of anterior cruciate ligament (ACL) reconstruction with bone marrow aspirate concentrate (BMAC) is gaining attention for its theoretical potential to enhance postoperative healing and recovery. However, its clinical benefits remain uncertain, and its high cost raises questions about efficacy. Hence, we systematically reviewed randomised controlled trials (RCTs) to evaluate the effectiveness of BMAC in ACL reconstruction.

METHODS

Our search included Cochrane, EMBASE, OVID, PubMed, and Scopus databases for RCTs evaluating the use of BMAC in ACL reconstruction. Primary outcomes focused on International Knee Documentation Committee (IKDC) scores and Lysholm scores. Secondary outcomes included MRI-related outcomes and postoperative complications. Statistical analysis was conducted using Review Manager 5.4 (Cochrane Collaboration), with heterogeneity assessed using Cochrane's Q test and I2 statistics.

RESULTS

221 patients from five RCTs were included, with 109 (49.3%) receiving BMAC augmentation. Follow-up ranged from 11.05 to 24 months. No significant differences were found in postoperative IKDC scores between the BMAC and control groups at, three, six and 12 months. The BMAC group had significantly higher IKDC scores at 24 months; however, this difference was unlikely to be clinically significant. No significant differences were observed in postoperative Lysholm scores at 12 or 24 months. MRI-related outcomes suggested potential graft recovery improvement with BMAC, and complication rates were comparable between groups.

CONCLUSION

In summary, biological augmentation with BMAC in ACL reconstruction does not significantly improve early patient-reported outcomes but offers potential benefits in graft recovery without increasing complication rates.

Bone-patellar tendon-bone, hamstring, and quadriceps tendon autografts for anterior cruciate ligament reconstruction in skeletally immature patients: a systematic review

INTRODUCTION

Historically, anterior cruciate ligament (ACL) ruptures in the paediatric age group were managed conservatively with bracing, casting, activity modification, and physical therapy. However, most of these patients had to reduce their sports activities, and secondary damages to the affected knee were prevalent.

SOURCE OF DATA

Published scientific literature in Embase, Web of Science, PubMed, and Google Scholar databases.

AREAS OF AGREEMENT

ACL reconstruction in children with open physes patients is debated. Any damage to the physes around the knee could lead to growth abnormalities and axial deviation of the knee.

AREAS OF CONTROVERSY

Different grafts are available and suitable for ACL reconstruction in skeletally immature patients; however, which graft performs better remains unclear.

GROWING POINTS

This systematic review compared bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and quadriceps tendon (QT) autografts for ACL reconstruction in skeletally immature patients. The joint laxity, Patient-reported outcome measures (PROMs), return to sport, and complications were compared.

AREAS TIMELY FOR DEVELOPING RESEARCH

In skeletally immature patients, HT, BPTB, and QT autografts for ACL reconstruction yielded good outcomes. Comparative studies are strongly required to establish the most suitable autograft.

Diagnostic performance of dual-energy computed tomography in detecting anterior cruciate ligament injuries: a systematic review and meta-analysis

OBJECTIVE

Anterior cruciate ligament (ACL) injuries are common and lead to significant physical limitations. While MRI is the diagnostic gold standard, its use is restricted in acute trauma cases due to contraindications and longer imaging times. Dual-energy computed tomography (DECT) has emerged as a potential alternative. This meta-analysis evaluates the diagnostic accuracy of DECT for ACL injuries.

MATERIALS AND METHODS

Following PRISMA guidelines, a comprehensive literature search was conducted using PubMed, Web of Science, Scopus, and Embase for studies published up to June 2024. Studies that provided diagnostic accuracy data for DECT in ACL ruptures were included. Metrics of diagnostic accuracy were aggregated using a bivariate random effects model.

RESULTS

The meta-analysis, which included five studies with a total of 191 patients, found that DECT had a pooled sensitivity of 88.1% (95% CI, 78.0-93.9%) and a specificity of 82.0% (95% CI, 62.0-92.7%) for diagnosing ACL ruptures, with an AUC of 0.92 (95% CI, 0.72-0.96). For complete ruptures, sensitivity was 83.2% (95% CI, 68.2-92.0%), and specificity was 94.9% (95% CI, 92.2-96.7%), with an AUC of 0.96 (95% CI, 0.81-0.98). In acute/subacute settings, sensitivity was 89.4% (95% CI, 76.8-95.6%), and specificity was 82.1% (95% CI, 56.2-94.2%), with an AUC of 0.93 (95% CI, 0.71-0.97).

CONCLUSION

Our findings suggest that DECT is a valuable diagnostic tool for ACL injuries, particularly as an adjunct or alternative when MRI is unavailable or contraindicated, enabling timely and accurate diagnosis.

Limited Use of Supervised Physical Rehabilitation Beyond 3 Months After Arthroscopic Anterior Cruciate Ligament Reconstruction With Greater Use in Female and Younger Patients

PURPOSE

To characterize the initiation and use of supervised physical rehabilitation after arthroscopic anterior cruciate ligament reconstruction (ACLR), including overall duration of rehabilitation and number of rehabilitation visits, and to describe demographic and clinical predictors of rehabilitation initiation and use characteristics.

METHODS

Patients aged 14 to 64 years in the United States who underwent ACLR from 2017 to 2020 were identified using the Merative MarketScan Database. For patients initiating rehabilitation within 45 days postoperatively, the overall duration and number of visits within 1 year after surgery were determined. Visits were categorized into rehabilitation phases, with visits 0-90 days postoperatively categorized as phase I, 91-180 days as phase II, 181-270 days as phase III, and 271-365 days as phase IV. Multivariable regression models identified predictors of rehabilitation initiation, duration in days, and number of visits.

RESULTS

Of 20,097 patients who underwent ACLR, 88.1% (n = 17,704) initiated postoperative rehabilitation, receiving phase I services. Additionally, 55.0% (n = 11,053) received phase II services, 17.0% (n = 3417) phase III services, and 3.9% (n = 779) phase IV services. The median duration was 104 days (interquartile range 63-157), and the median number of visits was 21 (interquartile range 12-32). Multiple significant predictors of rehabilitation initiation, duration, and number of visits were found.

CONCLUSIONS

Although most patients use supervised physical rehabilitation after ACLR, only 55% receive rehabilitation beyond 3 months and only 17% beyond 6 months after surgery. There are several significant drivers of rehabilitation initiation, overall duration, and number of visits. Female and younger patients have greater use of rehabilitation, and notable regional differences suggest an opportunity to improve standardization of care.

LEVEL OF EVIDENCE

Level III, retrospective descriptive study.

Graft Failure in Pediatric Patients After Bone-Patellar Tendon-Bone, Hamstring Tendon, or Quadriceps Tendon Autograft ACLR: A Systematic Review and Meta-analysis

Background

Anterior cruciate ligament (ACL) reinjury risk is high in young athletes, with graft failure rates as high as 23%. The optimal autograft choice to minimize reinjury risk in this population is unclear.

Purpose

To compare graft failure rates between bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and quadriceps tendon (QT) autografts in patients aged ≤18 years with a minimum follow-up (FU) of 24 months.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review of the literature between database inception and March 2022 encompassed PubMed/MEDLINE, Cochrane CENTRAL, Embase, and Web of Science Core Collection databases. Studies on autograft ACL reconstruction (ACLR) using HT, QT, or BPTB autograft in patients ≤18 years old with a minimum FU of 2 years were included. Graft failure rates were pooled and estimated using random-effects models via the inverse variance method and logit transformations. Meta-analyses were used to estimate failure rates and pairwise comparisons were conducted by autograft type when appropriate.

Results

A total of 24 studies comprising 2299 patients (HT: n = 1237, 44.8% female, 59.1-month mean FU; BPTB: n = 913, 67.3% female, 79.9-month mean FU; QT: n = 149, 36.4% female, 35.3-month mean FU) were included. HT exhibited the highest failure rate at 11.8% (95% CI, 9.0%-15.4%); failure rates for BPTB and QT were 7.9% (95% CI, 6.2%-10.0%) and 2.7% (95% CI, 1.0%-7.5%), respectively. HT had a significantly higher failure rate than both BPTB (Q = 5.01; P = .025) and QT (Q = 7.70; P = .006); BPTB had a significantly higher failure rate than QT (Q = 4.01; P = .045). Male patients were less likely than their female counterparts to experience graft failure after HT ACLR (odds ratio, 0.48; 95% CI, 0.25-0.95).

Conclusion

While the HT remains a common choice for ACLR, the current aggregate data indicate that BPTB and QT demonstrated significantly lower failure rates than HT ACLR in adolescent athletes ≤18 years old. The QT demonstrated the lowest failure rate in adolescents but also the lowest proportion of patients represented due to a paucity of published QT data, indicating a need for future studies with larger sample sizes that include QT autografts, reduced risk of bias, and consistent reporting on skeletal maturity and surgical technique to better determine the ideal autograft for active athletic populations ≤18 years old.

Local Infiltration Analgesia Versus Adductor Canal Block for Managing Pain After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

Background

Adductor canal block (ACB) and local infiltration analgesia (LIA) are frequently used to manage pain in patients after anterior cruciate ligament reconstruction (ACLR).

Purpose

To compare the difference in pain scores and opioid consumption between ACB and LIA for ancillary pain management in patients after ACLR.

Study Design

Systematic review; Level of evidence, 3.

Methods

A literature search was conducted using PubMed, MEDLINE, and Embase databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies that compared pain scores at 2, 6, 12, or 24 hours after ACLR or provided information on 24-hour opioid consumption were included. Of 240 publications initially screened by abstract and title, 4 studies were included, and data related to participant characteristics, anesthetic technique, and pain-related outcomes were extracted. The standardized mean difference (MD) in pain scores and morphine milligram equivalents consumed in 24 hours was compared using a random-effects model.

Results

In all studies, ropivacaine was the primary anesthetic used for LIA and ACB, with 1 study also employing bupivacaine as an alternative. The difference in pain scores between LIA and ACB was not significant at 2 hours (MD, 0.04 [95% CI, -0.22 to 0.29]; P = .79), 6 hours (MD, 0.16 [95% CI, -0.20 to 0.52]; P = .39), 12 hours (MD, 0.54 [95% CI, -0.49 to 1.56]; P = .31), or 24 hours (MD, 0.12 [95% CI, -0.10 to 0.34]; P = .28). The difference in morphine milligram equivalents was also not statistically significant (MD, -0.07 [95% CI, -0.25 to 0.11]; P = .68).

Conclusion

From this review, the authors suggest considering LIA over ACB because of its potential to offer comparable pain relief and opioid consumption while being less time intensive. However, the study results should be interpreted with caution, given the limited number of studies included.

Decoding the mechanical characteristics of the human anterior cruciate ligament entheses through graduated mineralization interfaces

The anterior cruciate ligament is anchored to the femur and tibia via specialized interfaces known as entheses. These play a critical role in ligament homeostasis and joint stability by transferring forces, varying in magnitude and direction between structurally and functionally dissimilar tissues. However, the precise structural and mechanical characteristics underlying the femoral and tibial entheses and their intricate interplay remain elusive. In this study, two thin-graduated mineralization regions in the femoral enthesis (~21 μm) and tibial enthesis (~14 μm) are identified, both exhibiting distinct biomolecular compositions and mineral assembly patterns. Notably, the femoral enthesis interface exhibits progressively maturing hydroxyapatites, whereas the mineral at the tibial enthesis interface region transitions from amorphous calcium phosphate to hydroxyapatites with increasing crystallinity. Proteomics results reveal that Matrix Gla protein uniquely enriched at the tibial enthesis interface, may stabilize amorphous calcium phosphate, while C-type lectin domain containing 11 A, enriched at the femoral enthesis interface, could facilitate the interface mineralization. Moreover, the finite element analysis indicates that the femoral enthesis model exhibited higher resistance to shearing, whereas the tibial enthesis model contributes to tensile resistance, suggesting that the discrepancy in biomolecular expression and the corresponding mineral assembly heterogeneities collectively contribute to the superior mechanical properties of both the femoral enthesis and tibial enthesis models. These findings provide novel perspectives on the structure-function relationships of anterior cruciate ligament entheses, paving the way for improved management of anterior cruciate ligament injury and regeneration.

Defensive Performance Declines in Ultimate Fighting Championship Fighters Following Anterior Cruciate Ligament Reconstruction

Purpose

To evaluate the impact anterior cruciate ligament reconstruction (ACLR) has on strike evasion rates, strike and landing rates, win percentage, and career longevity in Ultimate Fighting Championship (UFC) fighters.

Methods

UFC fighters who underwent ACLR from 1993 to 2022 were matched 2:1 with uninjured controls. The percentage of each injured fighter's career that occurred before ACLR was deemed the "index percentage." Injured fighter performance pre-/post-ACLR was compared with control metrics pre-/postindex percentage.

Results

Of the 82 patients with documented ACL injuries identified, 48 met the inclusion criteria. Of these, 27 returned for more than 2 fights and were paired with 54 controls. UFC fighters demonstrated return-to-sport rates of 81.25% and 56.25% for at least 1 and 2 fights, respectively. On average, it took 411.85 ± 174.73 (range, 165-879) days for fighters to return. All fighters had significantly lower evasion rates against total significant strikes, distance strikes, and head strikes, postindex (P < .05 for each). ACLR fighters had significantly lower submission attempts and evasion rates against clinch strikes, ground strikes, and total strikes, postindex (P < .05 for each). Controls had a significantly lower evasion rate against leg strikes, postindex. Both groups' win percentages significantly declined (ACLR, P = .001; control, P = .012). No significant difference in total career fights was observed (P = .873).

Conclusions

In this study, we found that most UFC fighters who undergo ACLR return to sport for at least 1 fight; however, just over half return for at least 2 fights. There was not a significant difference in career length between fighters who returned to sport following ACLR for at least 2 fights and their controls. Defensive performance, but not offensive performance, declined significantly following ACLR. All fighters demonstrated significant declines in their win percentage as their career progressed, irrespective of ACLR.

Level of Evidence

Level III, retrospective comparative study.

The in vitro elution characteristics of vancomycin from the ligament augmentation and reconstruction system

Purpose

In this study, we aimed to characterize the elution profile of the ligament augmentation and reconstruction system (LARS) immersed in different concentrations of vancomycin using different immersion methods and determine whether the amount of vancomycin released was lower than the toxic concentrations for osteoblasts and chondroblasts.

Methods

The LARS was presoaked with 5, 2.5 or 1.25 mg/mL vancomycin solutions or wrapped in presoaked sterile gauze. After 10 min, the rinsed and unrinsed LARS samples were eluted in 100 mL agitated 37°C phosphate-buffered saline. An ultraviolet spectrophotometer was used to analyze 1 mL samples taken after 10 min and 0.5, 1, 6, 12, 24h.

Results

Initially, no hysteresis was observed with vancomycin release into the solution at the tested conditions. The LARS elution profiles for different concentrations of the vancomycin solutions varied significantly. The amount of vancomycin released after 24 h was 9.10 ± 1.21, 5.29 ± 0.63 and 2.28 ± 0.59 mg for the 5, 2.5 and 1.25 mg/mL solutions, respectively. The amount of vancomycin released in the soaked group was significantly higher than in the rinsed and wrapped groups. The released amounts of vancomycin were below the toxic concentrations for osteoblasts and chondrocytes.

Conclusion

Soaked LARS can act as a reservoir for vancomycin, with the amount released and the elution profile dependent on rinsing, soaking solution concentration and soaking method. The eluted concentrations of vancomycin were lower than those previously reported for osteoblast and chondrocyte toxicity and higher than the minimal inhibitory concentrations for Staphylococci.

Level of Evidence

N/A.

Commitment of human mesenchymal stromal cells towards ACL fibroblast differentiation upon rAAV-mediated FGF-2 and TGF-β overexpression using pNaSS-grafted PCL films

Despite various clinical options, human anterior cruciate ligament (ACL) lesions do not fully heal. Biomaterial-guided gene therapy using recombinant adeno-associated virus (rAAV) vectors may improve the intrinsic mechanisms of ACL repair. Here, we examined whether poly(sodium styrene sulfonate)-grafted poly(ε-caprolactone) (pNaSS-grafted PCL) films can deliver rAAV vectors coding for the reparative basic fibroblast growth factor (FGF-2) and transforming growth factor beta (TGF-β) in human mesenchymal stromal cells (hMSCs) as a source of implantable cells in ACL lesions. Efficient and sustained rAAV-mediated reporter (red fluorescent protein) and therapeutic (FGF-2 and TGF-β) gene overexpression was achieved in the cells for at least 21 days in particular with pNaSS-grafted PCL films relative to all other conditions (up to 5.2-fold difference). Expression of FGF-2 and TGF-β mediated by rAAV using PCL films increased the levels of cell proliferation, the DNA contents, and the deposition of proteoglycans and of type-I and -III collagen (up to 2.9-fold difference) over time in the cells with higher levels of transcription factor expression (Mohawk, Scleraxis) (up to 1.9-fold difference), without activation of inflammatory tumor necrosis alpha especially when using pNaSS-grafted PCL films compared with the controls. Overall, the effects mediated by TGF-β were higher than those promoted by FGF-2, possibly due to higher levels of gene expression achieved upon rAAV gene transfer. This study shows the potential of using functionalized PCL films to apply rAAV vectors for ACL repair.

In the Acute Phase of Anterior Cruciate Ligament Rupture: Quantitative Assessment of Matrix Changes and Correlation between Different States of Meniscus and Adjacent Cartilage

OBJECTIVE

Cartilage and meniscus are important structures that maintain the health of the knee joint. Early detection of changes in the internal components of cartilage and meniscus before morphological changes occur is essential to prevent and delay the development of osteoarthritis (OA). This study was designed to determine the changes in the matrix composition of morphologically intact cartilage and meniscus during the acute phase of an anterior cruciate ligament (ACL) rupture, as well as the effect of different states of meniscus (intact or tear) on adjacent cartilage during the acute phase.

METHODS

This cross-sectional study compared and analyzed 50 patients in the acute phase of ACL rupture who underwent surgical treatment and 66 age-, weight- and height-matched healthy volunteers from May 2022 to May 2023 at our institution. Mean T2 relaxation times and effect sizes in different regions of tibiofemoral articular cartilage and meniscus were compared between the two groups using the Mann-Whitney nonparametric t-test, and correlations between different meniscal states and adjacent cartilage were analyzed.

RESULTS

Both in the lateral and medial compartments of the knee, T2 relaxation times were significantly higher in all subregions of cartilage and meniscus in the ACL rupture group (p < 0.05), and the site of injury was predominantly centered in the medial compartment (femur, p = 0.000; tibia, p = 0.000; anterior horn, p = 0.000). In the respective compartments, the posterior horn of the lateral meniscus showed a significant positive correlation with the mid-cartilage of the femoral and tibial (r = 0.566, p = 0.035; r = 0.611, p = 0.02); and the posterior horn of the medial meniscus showed a significant positive correlation with the posterior tibial cartilage (r = 0.668, p = 0.018).

CONCLUSION

During the acute phase of ACL rupture, the internal composition of the cartilage and meniscus undergoes significant changes, even if the morphology is intact. More importantly, the state of the meniscus significantly affects the internal composition of the adjacent cartilage. This is an early warning sign of OA, which should be closely monitored and carefully managed in clinical practice.

Evaluating the Efficacy of Peroneus Longus Tendon as an Autograft for Anterior Cruciate Ligament Reconstruction in Indian Female Patients: A Prospective Cohort Study

Background Anterior cruciate ligament (ACL) injuries are prevalent, especially among active individuals, and are increasingly observed even in Indian women who are not active in sports. ACL reconstruction (ACLR) is commonly performed using various graft options, but optimal choices for women remain debated. The aim of our study was to examine the use of the peroneus longus tendon as an autograft for ACLR in Indian female patients. Materials and methods A prospective cohort study was carried out on 44 non-athlete female patients who met the inclusion criteria. The study evaluates functional outcomes using the International Knee Documentation Committee (IKDC), Lysholm-Tegner, and American Orthopaedic Foot and Ankle Society (AOFAS) scores, as well as knee stability through clinical tests, over a one-year postoperative period. Results The study demonstrates significant improvements in knee function, with substantial increases in IKDC and Lysholm-Tegner scores from preoperative levels (p-value < 0.01), and effective restoration of knee stability, as shown by improved Lachman, Anterior Drawer, and Pivot Shift test results. Moreover, the peroneus longus graft had minimal impact on ankle morbidity, as indicated by consistent AOFAS scores before and after surgery. Conclusion The study highlights the peroneus longus tendon as a viable graft option for ACLR in symptomatic Indian female patients who were not active in sports, offering both mechanical strength and favorable functional outcomes without affecting the ankle strength or the function.

Overexpression of CGRP receptor attenuates tendon graft degeneration in anterior cruciate ligament reconstruction

Cell apoptosis or necrosis, extracellular matrix loss, and excessive inflammation may induce tendon graft degeneration. The impairment in the regeneration capability of nerve fibers and blood vessels may be the critical cause. Calcitonin gene-related peptide (CGRP), exhibiting a short half-life, favors cell proliferation, nerve fiber regeneration and angiogenesis. We aimed to investigate the effects of CGRP receptor-mediated signaling on tendon graft integrity and study if the modulation pathways are ascribed to cell proliferation, nerve fiber and blood vessel regeneration. A total of three groups in mice with ACL reconstruction were established: the control group (PBS treatment), the adenovirus vectors expressing CGRP receptor (CALCRL) treated group (Adv-Calcrl treatment), and the adenovirus vectors carrying shRNA targeting Calcrl treated group (Adv-shCalcrl treatment). The histological assessment indicated the Adv-Calcrl treatment was favored while the Adv-shCalcrl significantly impaired tendon graft integrity. TUNEL staining revealed a significant decreased number of apoptotic cells in the Adv-Calcrl group relative to the control group and the adv-shCalcrl group. Compared to the control group and the Adv-shCalcrl group, the Adv-Calcrl group showed significantly enhanced proliferation of nestin positive cells. Of note, the Adv-Calcrl treatment significantly increased EMCN expression at the tendon graft relative to the control and the Adv-shCalcrl groups, which may be ascribed to attenuation of the Hippo signaling pathway. Importantly, the Adv-Calcrl treatment significantly increased sensory nerve fibers and also PIEZO2 levels. Our results demonstrate the activation of CGRP receptor-mediated signaling attenuated tendon graft degeneration, which was ascribed to enhanced proliferation of Nestin positive cells, angiogenesis, and nerve fiber outgrowth.

Anterior Cruciate Ligament Reconstruction Utilizing Double Adjustable-Loop Suspensory Fixation Devices Provides Good Clinical Outcomes in Patients under the Age of 40 Years at Two-Year Follow-Up

Background: Anterior cruciate ligament reconstruction (ACLR) using double adjustable fixation gained popularity in the last decade due to its minimally invasive technique. However, suspensory fixation devices could be related to recurrent instability, poor clinical outcomes, and patient dissatisfaction. The present study aims to evaluate the clinical outcomes following ACLR using double adjustable-loop suspensory fixation devices in the demanding population of young patients. Methods: Between 2019 and 2022, 95 patients with knee post-traumatic anterior cruciate ligament insufficiency were treated with primary ACLR using semitendinosus quadrupled graft and double adjustable-loop suspensory fixation devices and followed for at least two years. Concomitant lesions were also treated at the same surgical time. The knee examination form of the International Knee Documentation Committee (IKDC) was used to assess clinical evaluation, and the return to physical activities using the Tegner Activity Scale was recorded. Patient-reported objective measures (PROMs) were also evaluated, including the IKDC subjective and Lysholm scores. Results: Sixty-six males and twenty-nine females with a mean age of 23.8 (range 18-37) and a mean BMI of 24.9 (SD ± 2.42) kg/m2 were included in this study. All patients were evaluated clinically as normal or nearly normal at the final follow-up. PROMs also significantly improved postoperatively (p < 0.05) compared to the preoperative values. The Tegner Activity Scale increased from 2 to 7, the IKDC mean score improved from 43.9 (±8.9) to 93.3 (±12.3), and the modified Lysholm from 47.3 (±11.1) to 92.9 (±16.6). No complications or adverse events were recorded. Conclusions: Anterior cruciate ligament reconstruction utilizing double adjustable-loop suspensory fixation devices provides good clinical and functional outcomes in young patients at a two-year follow-up.

Learning co-plane attention across MRI sequences for diagnosing twelve types of knee abnormalities

Multi-sequence magnetic resonance imaging is crucial in accurately identifying knee abnormalities but requires substantial expertise from radiologists to interpret. Here, we introduce a deep learning model incorporating co-plane attention across image sequences to classify knee abnormalities. To assess the effectiveness of our model, we collected the largest multi-sequence knee magnetic resonance imaging dataset involving the most comprehensive range of abnormalities, comprising 1748 subjects and 12 types of abnormalities. Our model achieved an overall area under the receiver operating characteristic curve score of 0.812. It achieved an average accuracy of 0.78, outperforming junior radiologists (accuracy 0.65) and remains competitive with senior radiologists (accuracy 0.80). Notably, with the assistance of model output, the diagnosis accuracy of all radiologists was improved significantly (p < 0.001), elevating from 0.73 to 0.79 on average. The interpretability analysis demonstrated that the model decision-making process is consistent with the clinical knowledge, enhancing its credibility and reliability in clinical practice.

Return to Play at Preinjury Level After Anterior Cruciate Ligament Reconstruction in Divisions II and III National Collegiate Athletic Association Student-Athletes

Background

The rates of return to play (RTP) after anterior cruciate ligament (ACL) reconstruction among professional and National Collegiate Athletic Association (NCAA) Division I athletes are well described in the orthopaedic literature. Less is known about these rates and risk factors for failure to RTP in Division II and III collegiate athletes.

Purpose

To determine the RTP rate after ACL reconstruction among Division II and III collegiate athletes and to explore the factors associated with RTP.

Study Design

Case series; Level of evidence, 4.

Methods

Demographic and RTP data were retrospectively reviewed for collegiate athletes who underwent ACL reconstructions across high-risk sports over 6 years (2015/16 to 2021/22 seasons) at 5 northeastern NCAA Division II and III institutions. Clinical data collected included Patient Acceptable Symptom State (PASS) on the Knee injury and Osteoarthritis Outcome Score (KOOS) Sport and Recreation questionnaire, graft type, concomitant reparative surgery, reinjury, need for reoperation, and time to RTP and return to preinjury level. Participants completed the survey using a secure web-based questionnaire sent via email or over the telephone at a minimum 6-month follow-up. Descriptive frequencies were calculated for all documented variables, with chi-square and analysis of variance statistics used to assess for associations and significant differences between variables.

Results

A total of 61 eligible student-athletes with primary ACL reconstructions were identified in this study period, and 40 knees were enrolled for analysis with a mean time from surgery to survey completion of 45.0 months. The overall RTP rate was 77.5% (31/40) at a mean of 10.1 months. However, only 50.0% (20/40) returned to their preinjury level of competitive play. There was a graft failure rate of 20% (8/40). Of the 32 athletes who did not reinjure their ACL, 81.25% (26/32) demonstrated a PASS on KOOS Sports and Recreation. Graft rerupture (P < .001) and reoperation (P = .007) had significant effects on rates of RTP. Concomitant procedures (P = .010) influenced return to preinjury level of sports. Injury during the active season versus the off-season significantly influenced KOOS PASS status (P = .038).

Conclusion

This study demonstrated that the rate of RTP after ACL reconstruction in this patient population of Division II and III collegiate athletes was 77.5%, with only 50% returning to their preinjury level of competitive play. The graft failure rate in this population was 20%. Surgical factors, such as concomitant surgeries and reinjury of ACL graft, as well as athlete-specific data, such as injury in the off-season, were statistically significant negative influences on patient outcomes. Further research is needed to evaluate other potential factors that may play a role in RTP after ACL reconstruction.

Diagnosis and treatment of anterior cruciate ligament injuries: Consensus of Chinese experts part II: Graft selection and clinical outcome evaluation

Background

In the recent decade, there has been substantial progress in the technologies and philosophies associated with diagnosing and treating anterior cruciate ligament (ACL) injuries in China. The therapeutic efficacy of ACL reconstruction in re-establishing the stability of the knee joint has garnered widespread acknowledgment. However, the path toward standardizing diagnostic and treatment protocols remains to be further developed and refined.

Objective

In this context, the Chinese Association of Orthopaedic Surgeons (CAOS) and the Chinese Society of Sports Medicine (CSSM) collaboratively developed an expert consensus on diagnosing and treating ACL injury, aiming to enhance medical quality through refining professional standards.

Methods

The consensus drafting team invited experts across the Greater China region, including the mainland, Hong Kong, Macau, and Taiwan, to formulate and review the consensus using a modified Delphi method as a standardization approach. As members of the CSSM Lower Limb Study Group and the CAOS Arthroscopy and Sports Medicine Study Group, invited experts concentrated on two pivotal issues: "Graft Selection" and "Clinical Outcome Evaluation" during the second part of the consensus development.

Results

This focused discussion ultimately led to a strong consensus on nine specific consensus terms.

Conclusion

The consensus clearly states that ACL reconstruction has no definitive "gold standard" graft choice. Autografts have advantages in healing capability but are limited in availability and have potential donor site morbidities; allografts reduce surgical trauma but incur additional costs, and there are concerns about slow healing, quality control issues, and a higher failure rate in young athletes; synthetic ligaments allow for early rehabilitation and fast return to sport, but the surgery is technically demanding and incurs additional costs. When choosing a graft, one should comprehensively consider the graft's characteristics, the doctor's technical ability, and the patient's needs. When evaluating clinical outcomes, it is essential to ensure an adequate sample size and follow-up rate, and the research should include patient subjective scoring, joint function and stability, complications, surgical failure, and the return to sport results. Medium and long-term follow-ups should not overlook the assessment of knee osteoarthritis.

Arthroscopic Primary Repair of Proximally Based Anterior Cruciate Ligament Tear With Augmentation and All-Epiphyseal Fixation

Arthroscopic anterior cruciate ligament (ACL) reconstruction has been the gold standard of care for ACL injuries for many years. Recently, there has been growing literature and interest in arthroscopic primary ACL repair in select patients with predominantly proximally based ACL tears. This Technical Note demonstrates a surgical technique that offers an efficient minimally invasive and physeal-sparing anatomic ACL repair with all-inside internal brace augmentation that in the short term has offered good results for our patients.

Relationship between Kinesiophobia and Dynamic Postural Stability after Anterior Cruciate Ligament Reconstruction: A Prospective Cohort Study

Anterior cruciate ligament (ACL) injuries in young, active patients generally require ACL reconstruction (ACLR) to restore mechanical and postural stability. The fear of movement or reinjury (kinesiophobia) has become increasingly recognized in the post-ACLR population; however, the association between restoration of postural stability and kinesiophobia remains largely unknown. The purpose of this study was to investigate changes in mean Tampa Scale of Kinesiophobia-11 (TSK-11), dynamic motion analysis (DMA) scores, and time on the testing platform, as well as any correlation between TSK-11 and mean overall and individual translational and rotational DMA scores during the first 12 months following ACLR. Cohort study. Patients undergoing ACLR were prospectively enrolled and dynamic postural stability and kinesiophobia based on the TSK-11 were collected within 2 days prior to surgery and at 6 and 12 months following ACLR. Dynamic postural stability was quantified by calculating a DMA score, with score calculated in three translational (anterior/posterior [AP], up/down [UD], medial/lateral [ML]) and three rotational (left/right [LR], flexion/extension, and internal/external rotation) independent planes of motions. Correlations between DMA and TSK-11 scores at each time point were analyzed. A total of 25 patients meeting inclusion criteria were analyzed. Mean overall DMA and TSK-11 scores increased with each successive testing interval. At 6-month follow-up, a weakly positive association between TSK-11 and DMA scores was appreciated based on overall DMA, AP, UD, ML, and LR. At 12 months, a moderately positive correlation was appreciated between TSK-11 and the translational, but not rotational, planes of motion. Following ACLR, lower level of kinesiophobia were found to be moderately associated with improved dynamic stability, especially in the translation planes of motion.

Anterior Cruciate Ligament Tear Detection Based on T-Distribution Slice Attention Framework with Penalty Weight Loss Optimisation

Anterior cruciate ligament (ACL) plays an important role in stabilising the knee joint, prevents excessive anterior translation of the tibia, and provides rotational stability. ACL injuries commonly occur as a result of rapid deceleration, sudden change in direction, or direct impact to the knee during sports activities. Although several deep learning techniques have recently been applied in the detection of ACL tears, challenges such as effective slice filtering and the nuanced relationship between varying tear grades still remain underexplored. This study used an advanced deep learning model that integrated a T-distribution-based slice attention filtering mechanism with a penalty weight loss function to improve the performance for detection of ACL tears. A T-distribution slice attention module was effectively utilised to develop a robust slice filtering system of the deep learning model. By incorporating class relationships and substituting the conventional cross-entropy loss with a penalty weight loss function, the classification accuracy of our model is markedly increased. The combination of slice filtering and penalty weight loss shows significant improvements in diagnostic performance across six different backbone networks. In particular, the VGG-Slice-Weight model provided an area score of 0.9590 under the receiver operating characteristic curve (AUC). The deep learning framework used in this study offers an effective diagnostic tool that supports better ACL injury detection in clinical diagnosis practice.

Outcomes of ACL Reconstruction Utilizing Supercritical CO2-Sterilized Allografts

Background

Allograft tendons are perceived to have a high ACL graft failure rate in primary anterior cruciate ligament (ACL) reconstruction (ACLR). Historical series may be biased by graft processing methods that degrade the biomechanical properties of donor tendons such as irradiation. Supercritical carbon dioxide (SCCO2) is a validated method of terminally sterilizing biomaterials at physiological temperatures without irradiation, but in vivo use of SCCO2-processed tendon allografts for primary ACLR has not been reported to date.

Hypothesis

ACLR with SCCO2 allografts would result in acceptable failure rates, subjective knee scores, and clinical evaluation at 2 years postoperatively.

Study Design

Case series; Level of evidence, 4.

Methods

Patients underwent primary ACLR with terminally sterilized SCCO2-processed human gracilis, peroneus longus, semitendinosus, tibialis anterior, and tibialis posterior tendon allografts. Patient demographics were collected, along with tendon donor age and sex. At 1 year postoperatively, subjective International Knee Documentation Committee (IKDC) and ACL-Return to Sport After Injury (ACL-RSI) scores were collected, as well as clinical evaluation. At 2 years postoperatively, the IKDC and ACL-RSI scores were repeated, and return to sports and further knee injuries were recorded.

Results

A total of 144 patients with a medianage of 26 (IQR 14) years formed the study group. Patients were predominately male (58%). The loss to follow-up rate was 8% (n = 12). The mean age of allograft tendon donors was 37 (range 17-58) years, and the majority were male (83%). The mean allograft diameter was 8.9 ± 1.0 mm. At 2 years, ACL graft failureoccurred in 5% (n = 7). All graft failureswere in patients aged ≤25 years (P = .007). Neither donor age (≤40 or >40 years) nor donor sex was associated with graft failure (P > .05). The median IKDC subjective score was 95 and ACL-RSI score was 75. There were no revisions for sepsis within the first 2 years postoperatively.

Conclusion

SCCO2 processing of allograft tendons demonstrated satisfactory clinical and patient-reported outcomes at 24 months postoperatively in a consecutive series of patients with primary ACLR, with similar ACL graft failure rates and subjective knee scores compared with those reported in published series of hamstring tendon autograft and fresh frozen nonirradiated allograft.

Medial Meniscectomy at the Time of ACL Reconstruction Is Associated With Postoperative Anterior Tibial Translation: A Retrospective Analysis

Background

Medial meniscal pathology and management have not been associated with postoperative anterior tibial translation (ATT) after anterior cruciate ligament reconstruction (ACLR).

Purpose

The purpose of this study was to evaluate the role of medial meniscal injury and treatment on pre- and postoperative ATT in the setting of primary ACLR. More specifically, the association between repairable medial meniscal tears, medial meniscectomy, and postoperative ATT, along with rates of revision surgery, was examined.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective review was performed for patients who underwent ACLR between January 1, 2010 and December 31, 2015 at a single center. Descriptive data were obtained from an institutional database for a total of 396 patients included in this study and followed for 1 year postoperatively. Statistical analysis was performed to examine associations of meniscal treatment with postoperative ATT measurements made by KT-1000 arthrometer.

Results

A total of 243 patients underwent isolated ACLR with autograft, 72 patients underwent autograft ACLR and partial medial meniscectomy (MMx) (ACLR + MMx), and 81 patients underwent autograft ACLR and medial meniscal repair (MMR) (ACLR + MMR). Patients with ACLR + MMx had higher mean age and body mass index compared with patients in the other groups. Patients who underwent ACLR + MMx had greater postoperative side-to-side ATT compared with patients undergoing ACLR (1.55 mm vs 1.07 mm; P = .04) or patients undergoing ACLR + MMR (1.55 mm vs 1.01 mm; P = .03). The ACLR + MMx group was less likely to have symmetric (<3-mm side-to-side difference) postoperative ATT compared with the ACLR group (85% vs 93%; P = .03). There was no difference in postoperative ATT between ACLR and ACLR + MMR. Postoperative return to the operating room was greater in the ACLR + MRR group compared with the ACLR + MMx group (21.9% vs 8.2%; P = .05).

Conclusion

MMx at the time of ACLR led to higher postoperative ATT compared with isolated ACLR or ACLR + MMR.

Complications in Anterior Cruciate Ligament Surgery and How to Avoid Them

Complications following anterior cruciate ligament (ACL) reconstruction can be detrimental to a patient's recovery and limit their ability to successfully return to sport. Arthrofibrosis, graft failure, and infection are a few examples of complications that can arise. Therefore, it is important for surgeons to recognize that each step during perioperative surgical decision making can impact patients' risk for such complications. The purpose of this paper is to discuss common complications following ACL reconstruction and how surgeons can avoid or reduce the risk of complications.

Methodology for Robotic In Vitro Testing of the Knee

The knee joint plays a pivotal role in mobility and stability during ambulatory and standing activities of daily living (ADL). Increased incidence of knee joint pathologies and resulting surgeries has led to a growing need to understand the kinematics and kinetics of the knee. In vivo, in silico, and in vitro testing domains provide researchers different avenues to explore the effects of surgical interactions on the knee. Recent hardware and software advancements have increased the flexibility of in vitro testing, opening further opportunities to answer clinical questions. This paper describes best practices for conducting in vitro knee biomechanical testing by providing guidelines for future research. Prior to beginning an in vitro knee study, the clinical question must be identified by the research and clinical teams to determine if in vitro testing is necessary to answer the question and serve as the gold standard for problem resolution. After determining the clinical question, a series of questions (What surgical or experimental conditions should be varied to answer the clinical question, what measurements are needed for each surgical or experimental condition, what loading conditions will generate the desired measurements, and do the loading conditions require muscle actuation?) must be discussed to help dictate the type of hardware and software necessary to adequately answer the clinical question. Hardware (type of robot, load cell, actuators, fixtures, motion capture, ancillary sensors) and software (type of coordinate systems used for kinematics and kinetics, type of control) can then be acquired to create a testing system tailored to the desired testing conditions. Study design and verification steps should be decided upon prior to testing to maintain the accuracy of the collected data. Collected data should be reported with any supplementary metrics (RMS error, dynamic statistics) that help illuminate the reported results. An example study comparing two different anterior cruciate ligament reconstruction techniques is provided to demonstrate the application of these guidelines. Adoption of these guidelines may allow for better interlaboratory result comparison to improve clinical outcomes.

Effects of Blood Flow Restriction Training in Patients before and after Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

(1) Objective: To examine the effects of blood flow restriction (BFR) training on muscle strength, cross-sectional area and knee-related function in patients selected for anterior cruciate ligament reconstruction (ACLR). (2) Methods: A literature search was conducted in PubMed, PEDro, Cochrane Library, Web of Science, SCOPUS, and ProQuest databases until 20 May 2024. Controlled clinical trials comparing the effects of BFR training with unrestricted training in patients before or after ACLR were selected. The GRADE approach was used to assess the degree of certainty for each meta-analysis. (3) Results: Ten studies were included (n = 287 participants). Standardized mean differences in favor of BFR training applied postoperatively were observed in knee extensor (SMD = 0.79; 95% CI = 0.06 to 1.52; I2: 68%) and flexor isokinetic strength (SMD = 0.53; 95% CI = 0.04 to 1.01; I2: 0%), and quadriceps cross-sectional area (SMD = 0.76; 95% CI = 0.27 to 1.26; I2: 0%). No changes were found in knee extensor isometric strength and knee-related function. The degree of certainty according to the GRADE was very low. (4) Conclusions: Very low degree of certainty suggests that BFR training provides additional benefits to unrestricted training on isokinetic strength and quadriceps cross-sectional area in patients undergoing ACLR.

Good clinical outcomes of anterior cruciate ligament reconstruction in patients over 60 years of age

PURPOSE

To evaluate the clinical outcomes following arthroscopic anterior cruciate ligament (ACL) reconstruction (ACLR) in patients over 60 years and to investigate the potential impact of preoperative osteoarthritis (OA) on these outcomes.

METHODS

A retrospective study included ACL-injured patients over 60 years who underwent primary arthroscopic ACLR between 2010 and 2020. The Lysholm score and the International Knee Documentation Committee (IKDC) score were assessed preoperatively and at the final follow-up. The Tegner activity scale was performed to evaluate patients' activity levels. Data on return to sports, patient satisfaction, subsequent injuries and complications were collected. Preoperative radiographs were used to grade OA according to the Kellgrene-Lawrence classification. Correlation analysis between OA and clinical outcomes was performed. The rates of achieving the minimal clinically significant difference and patient-acceptable symptoms state were documented.

RESULTS

A total of 37 patients were included in this study. The mean age at surgery was 62.3 ± 2.3 years, with a mean follow-up of 6.3 ± 3.2 years (range: 2.1-12.4). Patients showed statistically significant (all p < 0.001) improvements in the mean IKDC (38.9 ± 9.4-66.8 ± 12.5), Lysholm (48.8 ± 15.4-83.0 ± 12.8) and Tegner (1-3) scores. Fourteen patients (37.8%) returned to sports. No correlation was observed between the degree of preoperative OA and clinical outcomes (n.s.).

CONCLUSION

Patients over 60 years with symptomatic ACL-deficient knees could benefit from ACLR, even when mild to moderate OA is present preoperatively.

LEVEL OF EVIDENCE

Level IV.

Comparison of physical therapy utilization, timing of return-to-sport test completion, and hop test performance by age and between sexes in youth athletes after anterior cruciate ligament reconstruction

OBJECTIVE

To compare physical therapy (PT) utilization, timing of return-to-sport (RTS) test and hop test performance by age and between sexes in youth after anterior cruciate ligament reconstruction (ACLR).

DESIGN

Multicenter retrospective cohort.

METHODS

A retrospective review of adolescents after primary ACLR was conducted. Participants completed return-to-sport (RTS) tests including single-legged hop testing. PT frequency, average weekly visits, and timing of RTS test were calculated. T-tests assessed the effect of age and sex on average weekly PT visits and multivariable logistic regressions assessed odds of passing hop tests.

RESULTS

289 participants were included (15.7 ± 1.9 years). There was no difference in average weekly PT visits (p = 0.321) or time to RTS test (p = 0.162) by age. There were significant differences in average weekly PT visits (p = 0.047) and mean time from surgery to RTS test (p = 0.048) between sexes with small effect sizes (d = 0.24 and d = 0.21, respectively). Age and sex had no effect on odds of passing hop tests (OR, 1.29; 95% CI, 0.71-2.35 and OR, 0.79; 95%CI, 0.43-1.45, respectively).

CONCLUSION

In a youth cohort, age and sex may have no clinically important effect on PT visit utilization, timing of RTS test or hop test performance.

What is the impact of Kinesio taping on anterior cruciate ligament reconstruction: a systematic review and meta-analysis

PURPOSE

As a therapeutic intervention for several musculoskeletal illnesses, the benefits and effectiveness of Kinesio taping (KT) are currently unclear. This systematic review and meta-analysis's (MA) goal is to evaluate the effectiveness of KT for anterior cruciate ligament (ACL) reconstruction and its impact on clinical outcomes.

METHODS

A comprehensive search of online databases was done to discover relevant studies. Inclusion criteria included controlled or randomized clinical trials that were published in English. Changes in pain, flexion strength, and extension strength were among the outcomes of interest. RevMan 5.4 was used to extract and analyze data.

RESULTS

After satisfying the inclusion requirements, five studies were included in the MA. Pooled analysis showed that, in comparison with the intervention group, the control group had a statistically significant improvement in flexion strength (Standardized mean difference (SMD) = 0.44, 95% Confidence interval (CI) [0.01, 0.87], p = 0.04). Extension strength and pain, however, did not significantly differ between the intervention and control groups (SMD = 30, 95% CI [- 0.12, 0.72], p = 0.16), (SMD = 0.26, 95% CI [- 0.14, 0.66], p = 0.20), respectively.

CONCLUSIONS

This analysis suggests limited to no benefits of KA post-ACL reconstruction. While the control group surprisingly showed better improvement in flexion strength, no significant differences were found in extension strength and pain. Further rigorous trials are needed to confirm its utility in rehabilitation.

Predictive Refined Computational Modeling of ACL Tear Injury Patterns

Anterior cruciate ligament (ACL) ruptures are prevalent knee injuries, with approximately 200,000 ruptures annually, and treatment costs exceed USD two billion in the United States alone. Typically, the initial detection of ACL tears and anterior tibial laxity (ATL) involves manual assessments like the Lachman test, which examines anterior knee laxity. Partial ACL tears can go unnoticed if they minimally affect knee laxity; however, they will progress to a complete ACL tear requiring surgical treatment. In this study, a computational finite element model (FEM) of the knee joint was generated to investigate the effect of partial ACL tears under the Lachman test (GNRB® testing system) boundary conditions. The ACL was modeled as a hyperelastic composite structure with a refined representation of collagen bundles. Five different tear types (I-V), classified by location and size, were modeled to predict the relationship between tear size, location, and anterior tibial translation (ATT). The results demonstrated different levels of ATT that could not be manually detected. Type I tears demonstrated an almost linear increase in ATT, with the growth in tear size ranging from 3.7 mm to 4.2 mm, from 25% to 85%, respectively. Type II partial tears showed a less linear incline in ATT (3.85, 4.1, and 4.75 mm for 25%, 55%, and 85% partial tears, respectively). Types III, IV, and V maintained a nonlinear trend, with ATTs of 3.85 mm, 4.2 mm, and 4.95 mm for Type III, 3.85 mm, 4.25 mm, and 5.1 mm for Type IV, and 3.6 mm, 4.25 mm, and 5.3 mm for Type V, for 25%, 55%, and 85% partial tears, respectively. Therefore, for small tears (25%), knee stability was most affected when the tears were located around the center of the ligament. For moderate tears (55%), the effect on knee stability was the greatest for tears at the proximal half of the ACL. However, severe tears (85%) demonstrated considerable growth in knee instability from the distal to the proximal ends of the tissue, with a substantial increase in knee instability around the insertion sites. The proposed model can enhance the characterization of partial ACL tears, leading to more accurate preliminary diagnoses. It can aid in developing new techniques for repairing partially torn ACLs, potentially preventing more severe injuries.

Additional suture augmentation to anterior cruciate ligament reconstruction with hamstring autografts bring no benefits to clinical results, graft maturation and graft-bone interface healing

BACKGROUND

From the perspective of graft protection and early rehabilitation during the maturation and remodeling phases of graft healing, suture augmentation (SA) for anterior cruciate ligament reconstruction (ACLR) has attracted more and more attention.

STUDY DESIGN

Retrospective study.

PURPOSE

To determine whether the additional SA affects clinical results, graft maturation and graft-bone interface healing during two years follow-up after ACLR.

METHODS

20 ACLRs with additional SA (ACLR-SA group) and 20 ACLRs without additional SA (ACLR group) were performed between January 2020 and December 2021 by the same surgeon and were retrospectively analyzed. Pre- and postoperative International Knee Documentation Committee (IKDC) scores, Lysholm scores, graft failure and reoperation were evaluated. The signal/noise quotient (SNQ) of autografts and the signal intensity of graft-bone interface were analyzed. All 40 patients in ACLR-SA group and ACLR group completed 2-years follow-up.

RESULTS

There was no patient in the two cohorts experienced graft failure and reoperation. The postoperative IKDC and Lysholm scores have been significantly improved compared with preoperative scored in both ACLR-SA group and ACLR group, however, there was no significant difference between two groups. The SNQ of proximal graft of ACLR-SA group (14.78 ± 8.62 vs. 8.1 ± 5.5, p = 0.041) was significantly greater while the grades of graft-bone interface healing of posterior tibial was significantly lower than that of ACLR group at 1-year postoperatively (p = 0.03), respectively. There were no significant differences between the two groups of the SNQ of proximal, distal medial graft segments, and the graft-bone interface healing grades of anterior femoral, posterior femoral, anterior tibial and posterior tibial at other time points (p>0.05).

CONCLUSIONS

The additional SA in ACLR had no effect on IKDC scores, Lysholm scores, graft maturation and graft-bone interface healing at 2-year postoperatively. Our research does not support the routine use of SA in ACLR.

The efficacy of vitamin E in preventing arthrofibrosis after joint replacement

BACKGROUND

Arthrofibrosis is a joint disorder characterized by excessive scar formation in the joint tissues. Vitamin E is an antioxidant with potential anti-fibroblastic effect. The aim of this study was to establish an arthrofibrosis rat model after joint replacement and assess the effects of vitamin E supplementation on joint fibrosis.

METHODS

We simulated knee replacement in 16 male Sprague-Dawley rats. We immobilized the surgical leg with a suture in full flexion. The control groups were killed at 2 and 12 weeks (n = 5 per group), and the test group was supplemented daily with vitamin E (0.2 mg/mL) in their drinking water for 12 weeks (n = 6). We performed histological staining to investigate the presence and severity of arthrofibrosis. Immunofluorescent staining and α2-macroglobulin (α2M) enzyme-linked immunosorbent assay (ELISA) were used to assess local and systemic inflammation. Static weight bearing (total internal reflection) and range of motion (ROM) were collected for functional assessment.

RESULTS

The ROM and weight-bearing symmetry decreased after the procedure and recovered slowly with still significant deficit at the end of the study for both groups. Histological analysis confirmed fibrosis in both lateral and posterior periarticular tissue. Vitamin E supplementation showed a moderate anti-inflammatory effect on the local and systemic levels. The vitamin E group exhibited significant improvement in ROM and weight-bearing symmetry at day 84 compared to the control group.

CONCLUSIONS

This model is viable for simulating arthrofibrosis after joint replacement. Vitamin E may benefit postsurgical arthrofibrosis, and further studies are needed for dosing requirements.

Comparison of Graft Type and Fixation Method in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis Based on Randomized Control Studies

BACKGROUND

The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee. ACL reconstruction (ACLR) proves the standard for treating this injury. However, graft choice and method of fixation remain a heavily debated topic. This study investigates the following: bone-patellar tendon-bone (BPTB) vs. hamstring tendon (HT) autograft, single-bundle vs. double-bundle hamstring graft, and metal vs. bioabsorbable screws in ACLR.

METHODS

A systematic review was performed on PubMed and Google Scholar according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were collected on patient demographics, complications, and functionality scores including International Knee Documentation Committee (IKDC) and Lysholm scores. A systematic review and meta-analysis were conducted with Review Manager. Outcome measurements were determined using forest plots with significant differences considered p < 0.05.

RESULTS

Twenty-five studies were included, accounting for 2,170 patients. No statistically significant difference was appreciated when comparing BPTB to hamstring autografts. Patients who received a double bundle HT autograft exhibited significantly superior outcomes in terms of revision (p = 0.05), failure (p = 0.002), normal pivot shift tests (p = 0.04), and normal IKDC (p = 0.008). When comparing screw types, bioabsorbable screws had a greater Lysholm score (p = 0.01) and lower failure rates for copolymer screws (p = 0.03).

CONCLUSION

Overall, the data collected suggested that BPTB and HT autografts display similar postoperative results. However, if an HT autograft is used, the data suggest a double-bundle graft improves both functionality and decreases the possible complications. Finally, bioabsorbable screws prove superior to metal screws when looking at both functionality and failure rates. Further research into the superior graft type is still needed.

LEVEL OF EVIDENCE

Level II. See Instructions for Authors for a complete description of levels of evidence.

Comparative efficacy and safety of different surgical approaches for the treatment of anterior cruciate ligament injury: a Bayesian network meta-analysis protocol

INTRODUCTION

Anterior cruciate ligament (ACL) rupture can be treated surgically or non-surgically, with several surgical interventions available at present. However, the comparatively effective surgical intervention with relatively fewer side effects remains unknown. This study aims to fill in this gap by conducting a Bayesian network meta-analysis (NMA) and provide a theoretical basis for the clinical application.

METHOD AND ANALYSIS

We will perform a Bayesian NMA and will include randomised controlled trials (RCTs) published in English or Chinese that compare surgical intervention (ie, standard ACL reconstruction, ACL remnant-preserving reconstruction and ACL repair with suture augmentation to conservative therapy or studies that compare one surgical intervention to another for the symptom relief and function recovery of patients with ACL rupture. Primary outcome will be the proportion of patients with symptomatic and functional improvement measured by the Knee Injury and Osteoarthritis Outcome Score before and 6 months after treatment, with scores ranging from 0 (worst) to 100 (best). Secondary outcomes will be knee-specific quality of life (ACL QoL), return to activity and level of sport participation (Tegner or modified Tegner score), health-related QoL (EuroQol Group 5-Dimension 5-Level, EQ-5D-5L), resource use, intervention-related complications and patient satisfaction. We have developed search strategies for PubMed, Embase, the Cochrane Library and Web of Science, retrieving RCTs that meet the inclusion criteria from database inception to 1 December 2023. The methodological quality of the included RCTs will be assessed based on the Cochrane risk of bias table. The relative ranking probability of the best intervention will be estimated using the surface under the cumulative ranking curve. The Bayesian NMA will be conducted by using WinBUGS V.1.4.3. The Grading of Recommendations Assessment, Development and Evaluation approach will be applied to determine our confidence in an overall treatment ranking from the NMA.

ETHICS AND DISSEMINATION

Ethical approval for this study is not required because no private or confidential patient data will be used in this study. Findings of this study would be disseminated through the publication in a peer-reviewed medical journal.

PROSPERO REGISTRATION NUMBER

CRD42023437115.

Fragile Statistical Findings in Randomized Controlled Trials Evaluating Autograft Versus Allograft Use in Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To analyze the statistical stability of randomized controlled trials (RCTs) evaluating the surgical management of autografts versus allografts in the anterior cruciate ligament reconstruction (ACLR) literature and calculate the fragility index (FI) and fragility quotient and explore a subgroup analysis by calculating the proportion of outcome events where the FI was less than the number of patients lost to follow-up.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic search in the PubMed and Cochrane databases to identify RCTs published between 2000 and 2022 that investigated the use of autografts versus allografts in ACLR literature and reported dichotomous data. The fragility index of each dichotomous variable was calculated through the reversal of a single outcome event until significance was reversed. The fragility quotient was calculated by dividing each fragility index by the study sample size. The interquartile range also was calculated.

RESULTS

Of the 4407 articles screened, 23 met the search criteria, with 11 RCTs evaluating ALCR using autografts and allografts included for analysis. Two hundred and 18 outcome events with 32 significant (P < .05) outcomes and 186 nonsignificant (P ≥ .05) outcomes were identified. The overall fragility index and fragility quotient for all 218 outcomes were 6 subjects (interquartile range 5-8) and 0.058 (interquartile range 0.039-0.077). Fragility analysis of statistically significant outcomes and nonsignificant outcomes had a fragility index of 3.5 (interquartile range 1-5.5) and 6 (interquartile range 5-8), respectively. All of the studies reported a loss to follow-up where 45.5% (5) reported a loss to follow-up greater or equal to 6.

CONCLUSIONS

The RCTs in the ACLR peer-reviewed literature evaluating autograft versus allograft use are vulnerable to a small number of outcome event reversals and exemplify significant statistical fragility in statistically significant findings.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Why Your Patient May Need an ACL Reconstruction Plus Lateral Extra-Articular Tenodesis Procedure

Anterior cruciate ligament (ACL) tears are one of the most common knee injuries experienced by active individuals engaging in cutting sports. Despite improved surgical techniques and rehabilitation, the return to sport rate and re-tear rates remain unsatisfactory. Lateral extra-articular tenodesis (LET) is a procedure that has been growing in interest when performed in conjunction with ACL reconstruction. The benefits of adding an LET procedure to an ACL surgery may include greater rotational stability, decreased re-tear rates, and improved return to play. Level of evidence: V.

Anterior Cruciate Ligament Repair Using a Re-tensionable All-Suture Construct

Anterior cruciate ligament (ACL) tears are among the most common injuries to the knee. With recent improvements in imaging that allow for more precise identification of ACL tear patterns, improved techniques for repair, and advancements in biological augmentation, there has been a re-emerging interest in primary ACL repair, especially for acute proximal ACL tears. This article aims to describe a surgical technique for primary ACL repair using a re-tensionable all-suture-based construct.

Quantitative Magnetic Resonance Imaging of Lateral Compartment Articular Cartilage After Lateral Extra-articular Tenodesis

BACKGROUND

Concerns have arisen that anterior cruciate ligament reconstruction (ACLR) with lateral extra-articular tenodesis (LET) may accelerate the development of posttraumatic osteoarthritis in the lateral compartment of the knee.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate whether the augmentation of ACLR with LET affects the quality of lateral compartment articular cartilage on magnetic resonance imaging (MRI) at 2 years postoperatively. We hypothesized that there would be no difference in T1rho and T2 relaxation times when comparing ACLR alone with ACLR + LET.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A consecutive subgroup of patients at the Fowler Kennedy Sport Medicine Clinic participating in the STABILITY 1 Study underwent bilateral 3-T MRI at 2 years after surgery. The primary outcome was T1rho and T2 relaxation times. Articular cartilage in the lateral compartment was manually segmented into 3 regions of the tibia (lateral tibia [LT]-1 to LT-3) and 5 regions of the femur (lateral femoral condyle [LFC]-1 to LFC-5). Analysis of covariance was used to compare relaxation times between groups, adjusted for lateral meniscal tears and treatment, cartilage and bone marrow lesions, contralateral relaxation times, and time since surgery. Semiquantitative MRI scores according to the Anterior Cruciate Ligament OsteoArthritis Score were compared between groups. Correlations were used to determine the association between secondary outcomes (including results of the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, Lower Extremity Functional Scale, 4-Item Pain Intensity Measure, hop tests, and isokinetic quadriceps and hamstring strength tests) and cartilage relaxation.

RESULTS

A total of 95 participants (44 ACLR alone, 51 ACLR + LET) with a mean age of 18.8 years (61.1% female [58/95]) underwent 2-year MRI (range, 20-36 months). T1rho relaxation times were significantly elevated for the ACLR + LET group in LT-1 (37.3 ± 0.7 ms vs 34.1 ± 0.8 ms, respectively; P = .005) and LFC-2 (43.9 ± 0.9 ms vs 40.2 ± 1.0 ms, respectively; P = .008) compared with the ACLR alone group. T2 relaxation times were significantly elevated for the ACLR + LET group in LFC-1 (51.2 ± 0.7 ms vs 49.1 ± 0.7 ms, respectively; P = .03) and LFC-4 (45.9 ± 0.5 ms vs 44.2 ± 0.6 ms, respectively; P = .04) compared with the ACLR alone group. All effect sizes were small to medium. There was no difference in Anterior Cruciate Ligament OsteoArthritis Scores between groups (P = .99). Weak negative associations (rs = -0.27 to -0.22; P < .05) were found between relaxation times and quadriceps and hamstring strength in the anterolateral knee, while all other correlations were nonsignificant (P > .05).

CONCLUSION

Increased relaxation times demonstrating small to medium effect sizes suggested early biochemical changes in articular cartilage of the anterolateral compartment in the ACLR + LET group compared with the ACLR alone group. Further evidence and long-term follow-up are needed to better understand the association between these results and the potential risk of the development of osteoarthritis in our patient cohort.

Physeal-Sparing, All-Inside Anterior Cruciate Ligament Reconstruction Using Quadrupled Semitendinosus Autograft and Suture Tape Augmentation for Skeletally Immature Patients

The anterior cruciate ligament (ACL) is the primary soft-tissue structure for anterior stabilization of the knee and is one of the most frequently injured structures. The incidence of ACL injuries in children and adolescents ranges from 92 to 151 per 100,000 person-years. The choice of surgical treatment for this population group is controversial, with a widespread concern that adult reconstruction techniques may damage the epiphyseal plate, compromise growth, or cause deformity. In this article, we describe a physeal-sparing, all-inside ACL reconstruction technique for skeletally immature patients. This technique is supported by retrograde drilling of the femoral tunnel and retrograde drilling of the tibial tunnel, both of which are able to avoid the epiphyseal growth line. Fixation of the quadrupled semitendinosus autograft and suture tape augmentation are achieved by soft-tissue buttons on the femur and tibia. The surgical details of this reproducible reconstruction technique are elaborated.

Clinical and Radiological Outcomes After Combined ACL and MPFL Reconstruction Versus Isolated ACL Reconstruction for ACL Injury With Patellar Instability

BACKGROUND

An anterior cruciate ligament (ACL) injury accompanied by patellar instability (PI) is a topic that has gained orthopaedic surgeons' attention recently. Untreated PI is reportedly associated with worse clinical outcomes after isolated ACL reconstruction (ACLR) in patients after an ACL injury with PI. Nevertheless, the appropriate surgical approach and its long-term therapeutic effects in these patients remain unclear.

PURPOSE

(1) To compare the clinical and radiological outcomes between isolated ACLR (iACLR) and combined ACLR and medial patellofemoral ligament reconstruction (cAMR) in patients after an ACL injury with PI and (2) to explore the correlations between these 2 procedures and clinical and radiological outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 106 patients diagnosed with an ACL injury accompanied by PI between January 2016 and April 2021 were analyzed in this study. There were 34 patients excluded because of missing postoperative radiological data. Among the remaining 72 patients, 34 patients underwent iACLR, while 38 patients underwent cAMR. Demographic characteristics, intraoperative findings, and patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity score) were prospectively collected. Patellar alignment parameters and worsening patellofemoral osteoarthritis (PFOA) features (evaluated with the modified Whole-Organ Magnetic Resonance Imaging Score) were analyzed longitudinally on magnetic resonance imaging. The Kujala score was used to evaluate the functional recovery of the patellofemoral joint, and redislocations of the patella were prospectively recorded. Finally, multivariate logistic regression analysis was used to explore the correlations between these 2 procedures and clinical (not achieving the minimal detectable change [MDC] for the Lysholm score) and radiological (worsening PFOA features) outcomes.

RESULTS

The mean follow-up duration was 28.9 ± 6.2 and 27.1 ± 6.8 months for the iACLR and cAMR groups, respectively (P = .231). Significantly higher Lysholm scores (88.3 ± 9.9 vs 82.1 ± 11.1, respectively; P = .016) and subjective International Knee Documentation Committee scores (83.6 ± 11.9 vs 78.3 ± 10.2, respectively; P = .046) were detected in the cAMR group compared with the iACLR group postoperatively. The rates of return to preinjury sports were 20.6% and 44.7% in the iACLR and cAMR groups, respectively (difference, 24.1% [95% CI, 3.3%-45.0%]; P = .030). Moreover, the rates of worsening PFOA features were 44.1% and 18.4% in the iACLR and cAMR groups, respectively (difference, 25.7% [95% CI, 4.9%-46.4%]; P = .018). In addition, significantly higher Kujala scores (87.9 ± 11.3 vs 80.1 ± 12.0, respectively; P = .006), lower redislocation rates (0.0% vs 11.8%, respectively; difference, 11.8% [95% CI, 0.9%-22.6%]; P = .045), and significantly better patellar alignment were detected in the cAMR group compared with the iACLR group postoperatively. Furthermore, multivariate logistic regression analysis determined that iACLR and partial lateral meniscectomy were significantly correlated with not achieving the MDC for the Lysholm score and worsening PFOA features in our study population.

CONCLUSION

In patients after an ACL injury with PI, cAMR yielded better clinical and radiological outcomes compared with iACLR, with better patellar stability and a lower proportion of worsening PFOA features. Furthermore, not achieving the MDC for the Lysholm score and worsening PFOA features were significantly correlated with iACLR and partial lateral meniscectomy. Our study suggests that cAMR may be a more appropriate procedure for patients after an ACL injury with PI, which warrants further high-level clinical evidence.

Moment arm and torque generating capacity of semitendinosus following tendon harvesting for anterior cruciate ligament reconstruction: A simulation study

Altered semitendinosus (ST) morphology and distal tendon insertion following anterior cruciate ligament reconstruction (ACLR) may reduce knee flexion torque generating capacity of the hamstrings via impaired ST force generation and/or moment arm. This study used a computational musculoskeletal model to simulate mechanical consequences of tendon harvest for ACLR on ST function by modeling changes in ST muscle tendon insertion point, moment arm, and torque generating capacity across a physiological range of motion. Simulated ST function was then compared between ACLR and uninjured contralateral limbs. Magnetic resonance imaging from 18 individuals with unilateral history of ACLR involving a hamstring autograft was used to analyse bilateral hamstring muscle (ST, semimembranosus, bicep femoris long head and short head) morphology and distal ST tendon insertion. The ACLR cohort was sub-grouped into those with and without ST regeneration. For each participant with ST regeneration (n = 7), a personalized musculoskeletal model was created including postoperative remodeling of ST using OpenSim 4.1. Knee flexion and internal rotation moment arms and torque generating capacities of hamstrings were evaluated. Bilateral differences were calculated with an asymmetry index (%) ([unaffected limb-affected limb]/[unaffected limb + affected limb]*100%). Smaller moment arms or knee torques within injured compared to uninjured contralateral limbs were considered a deficit. Compared to uninjured contralateral limbs, ACLR limbs with tendon regeneration (n = 7) had minor reductions in knee flexion (5.80% [95% confidence interval (CI) = 3.97-7.62]) and internal rotation (4.92% [95% CI = 2.77-7.07]) moment arms. Decoupled from muscle morphology, altered ST moment arms in ACLR limbs with tendon regeneration resulted in negligible deficits in knee flexion (1.20% [95% CI = 0.34-2.06]) and internal rotation (0.24% [95% CI = 0.22-0.26]) torque generating capacity compared to uninjured contralateral limbs. Coupled with muscle morphology, ACLR limbs with tendon regeneration had substantial deficits in knee flexion (19.32% [95% CI = 18.35-20.28]) and internal rotation (15.49% [95% CI = 14.56-16.41]) torques compared to uninjured contralateral limbs. Personalized musculoskeletal models with measures of ST distal insertion and muscle morphology provided unique insights into post-ACLR ST and hamstring function. Deficits in knee flexor and internal rotation moment arms and torque generating capacities were evident in those with ACLR even when tendon regeneration occurred. Future studies may wish to implement this framework in personalized musculoskeletal models following ACLR to better understand individual muscle function for injury prevention and treatment evaluation.

Preferences in anterior cruciate ligament reconstruction: A survey among orthopedic surgeons in China

The purpose of this study was to reveal the current trends and preferences of Chinese orthopedic surgeons regarding anterior cruciate ligament (ACL) reconstruction through a nationwide web-based survey conducted in China. The survey questionnaire was distributed via WeChat to the chairmen of provincial orthopedic and sports medicine organizing committees in China, who then shared it in their respective WeChat workgroups. The questionnaire consisted of 52 multiple-choice questions covering 8 sections. Data collection was implemented by Questionnaire Star. A total of 812 valid questionnaires were returned: 94.21% of the respondents preferred single-bundle reconstruction of ACL, while 61.70% preferred autogenous semitendinosus plus gracilis reconstruction; 76.35% of the respondents preferred establishing the femoral tunnel first, while 47.29% preferred establishing the femoral tunnel through a medial auxiliary approach; and 85.10% of the respondents recommended patients to undergo surgery within 3 months after ligament injury. Besides, the vast majority of respondents chose to retain the ligamentous remnant bundle (92.98%) and recommended routine use of knee braces postoperatively (94.09%). It is recommended to perform arthroscopic single-bundle ACL reconstruction with the remnant preserving technique using a hamstring autograft within 3 months of ACL rupture, with support of postoperative functional braces.