Anterior Cruciate Ligament Reconstruction Surgery Outcomes: A Comparison Between Patients Who Underwent the Procedure During the COVID-19 Pandemic and a Cohort Treated Prior to the Pandemic.

Background and objective During the coronavirus disease 2019 (COVID-19) pandemic, many elective orthopedic surgeries, including anterior cruciate ligament reconstruction (ACLR), were temporarily postponed. The purpose of this study was to compare the outcomes of ACLR in patients who underwent surgery during the COVID-19 pandemic with those in a cohort treated before the pandemic. Materials and methods This retrospective review compared patients who underwent primary ACLR during two periods: March to June 2020 (the pandemic group) and January to December 2018 (the pre-pandemic group). Matched cohorts (1:1) were created using propensity matching. Time from injury-to-first visit, injury-to-surgery, and first visit-to-surgery were calculated. Subjective and objective outcomes, minimal clinically important difference (MCID) achievement, and complication rates were recorded for up to two years postoperatively. Statistical analysis included 𝛘2 or Fisher's exact tests for categorical data, and t- or Wilcoxon signed-rank tests for continuous data with significance set at P < 0.05. Results The pandemic and pre-pandemic groups consisted of 33 and 217 patients, respectively. Matched cohorts consisted of 33 patients each. The time from injury-to-surgery and the first visit-to-surgery was prolonged in the pandemic group. When unmatched, visual analog scale (VAS) scores at three months postoperatively and Patient-Reported Outcomes Measurement Information System (PROMIS)-pain interference (PI) at six months postoperatively and at the final follow-up were higher in the pandemic group. When matched, PROMIS-PI at six months postoperatively was higher in the pandemic group, and VAS scores at one year postoperatively were higher in the pre-pandemic group. MCID achievement and complication rates did not significantly differ between the groups. Conclusions ACLR procedures were significantly delayed in the early months of the COVID-19 pandemic. While patients treated before and during the pandemic experienced varying pain levels during recovery, their functional outcomes, MCID achievement, and complication rates did not differ significantly.

Comparison of Contralateral ACL Rupture Versus ACL Graft Rupture in Australian Netballers After ACL Reconstruction.

Background: Netball is a popular sport worldwide, particularly for women. However, its nature puts players at high risk for anterior cruciate ligament (ACL) injury. Purpose: To determine (1) the prevalence of ACL graft rupture and contralateral ACL (CACL) rupture in Australian female netballers after ACL reconstruction (ACLR) and (2) the rate of return to sports (RTS) and psychological readiness. Study Design: Cohort study; Level of evidence, 3. Methods: A patient database identified 332 consecutive female netball players who underwent ACLR with hamstring tendon autografts performed by 2 surgeons between 2007 and 2015. Patients were retrospectively surveyed at a minimum of 7 years postoperatively-including details of a second ACL injury to either knee, RTS, and psychological readiness per the ACL-Return to Sport After Injury (ACL-RSI) score. Multivariate regression assessed the association between selected variables and repeat ACL injury. Results: A total of 267 patients (80%) were included with a mean follow-up of 8.4 years (range, 7-15 years). ACL graft rupture and CACL rupture occurred in 11 (4%) and 27 (10%) patients, respectively, at 7 years postoperatively. The ACL graft had a survival rate of 99%, 97%, 97%, and 96% at 1, 2, 5, and 7 years after surgery, respectively. The native CACL had a survival rate of 100%, 99%, 94%, and 90% at 1, 2, 5, and 7 years, respectively. Adolescents had a 4.5 times greater hazard for ACL graft rupture (95% CI, 1.4-14.6; P = .014) and a 2.5 times greater hazard for CACL rupture (95% CI, 1.2-5.5; P = .021) compared with adults. CACL injury was also associated with a return to level 1-including jumping, hard pivoting, and cutting-sports (hazard ratio, 10.3 [95% CI, 1.4-77.1]; P = .023). Most (62%) participants returned to netball, with those with higher ACL-RSI scores more likely to RTS. Conclusion: The prevalence of repeat ACL injury was higher in the contralateral knee (10%) than the ACL-reconstructed knee (4%) at 7 years postoperatively. ACLR was a suitable option for female netballers who sustained an ACL rupture with low long-term rates of graft rupture. Repeat ACL injuries to either knee were more common in adolescents and those who returned to cutting and pivoting sports.

Evaluation of Bony Femoral Morphological Parameters in Anterior Cruciate Ligament Injury Using Magnetic Resonance Imaging: A Retrospective Unmatched Case-Control Study.

Background Over time, there has been a noticeable increase in anterior cruciate ligament (ACL) injuries. The current imperative is to anticipate predisposing factors and proactively prevent ACL injuries. The occurrence of ACL injuries has been linked to diverse factors associated with the morphology of the distal femur. Objectives Through this study, we aim to compare the anatomic variables of distal femur morphology such as notch width (NW), bicondylar width (BW), notch entrance width (NEW), and notch width index (NWI) between patients with ACL injuries and non-injured patients using MRI. We also aim to make a comparison of these factors between male and female genders to assess the gender variability. Material and methods A retrospective case-control study was conducted amongst patients who underwent MRI Knee scan for clinical suspicion of internal derangement during the study period. We selected the first 125 individuals who were found to have ACL injury in the MRI scans and selected another 125 individuals who had an intact ACL in the scans, to serve as controls in the study. Demographic information was retrieved from the hospital's electronic records, and the assessment of NW, NWI, BW, and NEW was conducted through a review of MRI sequences. They were then compared between the cases and control groups, as well as between male and female genders. Results The ACL-injured group exhibited statistically significant reductions in NW and NWI. While 17.39 mm was the mean NW among cases, 17.86 was the mean value among controls. Similarly, the mean NWI was 0.25 among patients with ACL injuries and 0.27 among controls. Gender-based comparisons also revealed statistically significant differences in NW and NWI measurements, where females were reported to have comparatively lower measurements. The mean NW for males and females in the injured group were 18.26 mm and 15.40 mm, respectively, while it was 18.71 mm and 16.90 mm, respectively, in the control group. In the case of NEW, males in the injured group had a slightly higher value (21.33 mm) than the controls (20.65). Females on the other hand exhibited a lower mean value of NEW in ACL-injured group (18.51 mm) in comparison to the non-injured (18.79 mm). BW did not seem to show a significant difference between the two groups. Conclusions In the studied population, ACL injuries demonstrated a higher occurrence in individuals with a narrow femoral intercondylar NWI. If any of these characteristics are identified in an MRI, it may be helpful to identify individuals who are at a higher risk of developing ACL injuries and may thereby help in planning preventative strategies.

Proprioception After Primary Repair of the Anterior Cruciate Ligament.

BACKGROUND: Primary repair of the anterior cruciate ligament (ACL) has some potential advantages over the reconstruction technique, which include but are not limited to better knee sensation due to preservation of the natural ACL tissue in patients compared with tendon graft. Proprioception is impaired after ACL injuries and the sense of the joint position is lost. PURPOSE/HYPOTHESIS: The purpose of this study was to compare arthroscopic ACL primary repair and ACL reconstruction techniques clinically and functionally and analyze the differences in proprioception. It was hypothesized that primary repair would restore knee joint proprioception more successfully because the original tissue of the ACL is preserved. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 63 patients (34 underwent reconstruction and 29 underwent primary repair between 2017 and 2020) and 33 healthy controls, as well as the healthy knees of the operated groups, were evaluated between 24 and 48 months (mean, 29 months) postoperatively. Patients with proximal femoral avulsion tears and stump quality suitable for repair underwent primary repair, and those with tears outside these criteria underwent reconstruction using hamstring tendon autograft. Proprioception was evaluated using the active joint position sensation method during weightbearing, with a digital inclinometer used to measure differences between the target and achieved flexion angles of 15°, 30°, and 60°. RESULTS: At 15° of knee flexion, the deviation angles for the healthy knee of the reconstruction and primary repair groups were significantly smaller than those of the control group (P < .001), but there was no statistically significant difference between the groups in terms of deviation angle at 30° and 60° of flexion. The deviation angle of the operated knees was statistically significantly larger in the reconstruction group than in the primary repair group at all angles. The deviation angles at 15°, 30°, and 60° were 2.83°, 2.66°, and 2.66° in the reconstruction group and 1.00°, 1.00°, and 1.33° in the primary repair group, respectively (P < .001). There was no statistically significant difference between the reconstruction and primary repair groups in terms of clinical scores. CONCLUSION: Primary ACL repair can preserve proprioception in a well-selected patient group. In short-term follow-up, primary repair of the ACL in patients with proximal femoral avulsion tears and stump quality suitable for repair appears to be proprioceptively protective. Future studies are needed to clarify the long-term consequences of primary repair on proprioception in a larger population.

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

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

Impact of Lateral Extra-Articular Procedure Augmentation on Rerupture Risk and Tegner Activity Scale Outcomes in Adolescent Anterior Cruciate Ligament: A Matched Comparative Study With a Minimum 2-Year Follow-up.

BACKGROUND: Despite the well-established role of lateral extra-articular procedures (LEAPs) in reducing failure rates after anterior cruciate ligament (ACL) reconstruction (ACLR) in the adult population, similar in-depth research for the adolescent and pediatric population remains lacking. PURPOSE: To examine the effect of the LEAP augmentation on the rerupture rate after ACLR in patients aged <18 years. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This was a retrospective analysis of prospectively collected data from October 2012 to June 2020, involving adolescents <18 years old undergoing primary ACLR with a minimum follow-up of 2 years. Two groups, matched for age, sex, Tegner activity scale, and presence of meniscal injury, were established: ACLR alone and ACLR+LEAP augmentation. The primary outcome measure was the rate of rerupture after ACLR. The secondary outcome measures were the rate of non-graft rupture related reoperation after ACLR; rate of return to sport (RTS) rate, timing, and level compared with preinjury status; and functional scores including the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) (Pain, Symptoms, Activities of Daily Living, Sport and Recreation, and Quality of Life), Tegner activity scale score, ACL Return to Sport after Injury (ACL-RSI) score, and Lysholm score. RESULTS: After accounting for follow-up losses, we analyzed 132 patients who underwent ACLR alone and 121 patients who underwent ACLR+LEAP from the initial 147 per group. The mean age of the patients in both groups was 16.1 years (SD, 1.1 and 1.0 years, respectively), with similar patient and injury characteristics across both groups (P > .05). Both groups also showed comparable preoperative functional scores. A significantly lower preoperative ACL-RSI score was observed in the ACLR-alone group compared with the ACLR+LEAP group (P = .0044). Graft rupture was significantly less common in the ACLR+LEAP group (2.5%) than in the ACLR-alone group (13.6%) (P = .002). The attributable risk reduction for ACLR+LEAP was 11.1%, and the calculated number needed to treat was 9. Kaplan-Meier analysis showed significantly better rerupture-free survival at 5 years for the ACLR+LEAP group (P = .001). Cox regression confirmed a 6-fold increased rerupture risk in the ACLR-alone group (P = .004). At the final follow-up, despite similar IKDC, KOOS, Lysholm, and ACL-RSI values across both groups, the ACLR+LEAP group had a significantly higher Tegner score (7.2 vs 6.3; P = .0042). No significant differences were observed in RTS rates or sport level compared with preinjury states between the groups. CONCLUSION: ACLR+LEAP augmentation significantly reduced rerupture risk and facilitated higher postoperative activity levels in adolescents. REGISTRATION: NCT02511158 (ClinicalTrials.gov identifier).

Tibial Spine Fractures in the Child and Adolescent Athlete: A Systematic Review and Meta-analysis.

BACKGROUND: Tibial spine fractures (TSFs) are uncommon injuries that may result in substantial morbidity in children. A variety of open and arthroscopic techniques are used to treat these fractures, but no single standardized operative method has been identified. PURPOSE: To systematically review the literature on pediatric TSFs to determine the current treatment approaches, outcomes, and complications. STUDY DESIGN: Meta-analysis; Level of evidence, 4. METHODS: A systematic review of the literature was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) guidelines using PubMed, Embase, and Cochrane databases. Studies evaluating treatment and outcomes of patients <18 years old were included. Patient demographic characteristics, fracture characteristics, treatments, and outcomes were abstracted. Descriptive statistics were used to summarize categorical and quantitative variables, and a meta-analytic technique was used to compare observational studies with sufficient data. RESULTS: A total of 47 studies were included, totaling 1922 TSFs in patients (66.4% male) with a mean age of 12 years (range, 3-18 years). The operative approach was open reduction and internal fixation in 291 cases and arthroscopic reduction and internal fixation in 1236 cases; screw fixation was used in 411 cases and suture fixation, in 586 cases. A total of 13 nonunions were reported, occurring most frequently in Meyers and McKeever type III fractures (n = 6) and in fractures that were treated nonoperatively (n = 10). Arthrofibrosis rates were reported in 33 studies (n = 1700), and arthrofibrosis was present in 190 patients (11.2%). Range of motion loss occurred significantly more frequently in patients with type III and IV fractures (P < .001), and secondary anterior cruciate ligament (ACL) injury occurred most frequently in patients with type I and II fractures (P = .008). No statistically significant differences were found with regard to rates of nonunion, arthrofibrosis, range of motion loss, laxity, or secondary ACL injury between fixation methods (screw vs suture). CONCLUSION: Despite variation in TSF treatment, good overall outcomes have been reported with low complication rates in both open and arthroscopic treatment and with both screw and suture fixation. Arthrofibrosis remains a concern after surgical treatment for TSF, but no significant difference in incidence was found between the analysis groups. Larger studies are necessary to compare outcomes and form a consensus on how to treat and manage patients with TSFs.

Nonoperative Management, Repair, or Reconstruction of the Medial Collateral Ligament in Combined Anterior Cruciate and Medial Collateral Ligament Injuries-Which Is Best? A Systematic Review and Meta-analysis.

BACKGROUND: Combined injury of the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) is a common injury pattern and accounts for 20% of all ligamentous knee injuries. Despite advancements in surgical technique, there is no up-to-date consensus regarding the superiority of nonoperative versus operative management in higher-grade MCL tears of combined ACL-MCL injuries. PURPOSE: To interpret recent literature on treatment options and to provide an updated evidence-based approach for management of combined ACL-MCL knee injuries. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: We performed a systematic review on outcomes following treatment of concomitant ACL and MCL injuries. A computerized search was conducted in PubMed, Embase.com, and Scopus.com. Authors independently assessed eligible studies and screened titles and abstracts. Articles reporting on patients with concomitant ACL and MCL injuries with or without concomitant procedures were included. Data regarding study design, sample size, patient age and sex, length of follow-up, timing of surgery, indications, surgical methods, concomitant procedures, outcomes, and complications were recorded. Patient-reported outcomes (PROs) and functional outcomes, including Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee scores, Lysholm and Tegner scores, and range of motion, were estimated via meta-analysis and compared statistically by surgical approach. RESULTS: In total, 18 studies were included in the systematic review with level 1 to level 4 evidence, with a total of 1,534 cases, were included in the systematic review. Of these, 16 studies with sufficient statistical reporting including 997 cases with sufficient follow-up were included in meta-analysis. Three different approaches to combined ACL-MCL injuries were identified: ACL reconstruction with (1) nonoperative MCL, (2) MCL repair, and (3) MCL reconstruction. There was no statistical difference between nonoperative versus surgically managed MCL injuries for PROs, range of motion at final follow up, or quadriceps strength. CONCLUSION: Reconstruction of combined injury in a delayed fashion facilitates return of range of motion and may allow time for low-grade MCL tears to heal. If residual valgus or anteromedial rotatory laxity remains after a period of rehabilitation, then concomitant surgical management of ACL and MCL injuries is warranted. Avulsion MCL injuries and Stener-type lesions may benefit from early repair techniques.

Injury risk functions for the four primary knee ligaments.

The purpose of this study was to develop injury risk functions (IRFs) for the anterior and posterior cruciate ligaments (ACL and PCL, respectively) and the medial and lateral collateral ligaments (MCL and LCL, respectively) in the knee joint. The IRFs were based on post-mortem human subjects (PMHSs). Available specimen-specific failure strains were supplemented with statistically generated failure strains (virtual values) to accommodate for unprovided detailed experimental data in the literature. The virtual values were derived from the reported mean and standard deviation in the experimental studies. All virtual and specimen-specific values were thereafter categorized into groups of static and dynamic rates, respectively, and tested for the best fitting theoretical distribution to derive a ligament-specific IRF. A total of 10 IRFs were derived (three for ACL, two for PCL, two for MCL, and three for LCL). ACL, MCL, and LCL received IRFs in both dynamic and static tensile rates, while a sufficient dataset was achieved only for dynamic rates of the PCL. The log-logistic and Weibull distributions had the best fit (p-values: >0.9, RMSE: 2.3%-4.7%) to the empirical datasets for all the ligaments. These IRFs are, to the best of the authors' knowledge, the first attempt to generate injury prediction tools based on PMHS data for the four knee ligaments. The study has summarized all the relevant literature on PHMS experimental tensile tests on the knee ligaments and utilized the available empirical data to create the IRFs. Future improvements require upcoming experiments to provide comparable testing and strain measurements. Furthermore, emphasis on a clear definition of failure and transparent reporting of each specimen-specific result is necessary.

Age and Gender-Dependence of Single-and Bi-Exponential T1ρ MR Parameters in Knee Ligaments.

BACKGROUND: There is limited understanding of differences in the composition and structure of ligaments between healthy males and females, and individuals of different ages. Females present higher risk for ligament injuries than males and there are conflicting reports on its cause. This study looks into T1ρ parameters for an explanation as it relates to proteoglycan, collagen, and water content in these tissues. PURPOSE: To investigate gender-related and age-related differences in T1ρ parameters in knee joint ligaments in healthy volunteers using a T1ρ -prepared zero echo-time (ZTE)-based pointwise-encoding time-reduction with radial acquisition (T1ρ -PETRA) sequence. STUDY TYPE: Prospective. POPULATION: The study group consisted of 22 healthy subjects (11 females, ages: 41 ± 18 years, and 11 males, ages: 41 ± 14 years) with no known inflammation, trauma, or pain in the knee joint. FIELD STRENGTH/SEQUENCE: A T1ρ -prepared 3D-PETRA sequence was used to acquire fat-suppressed images with varying spin-lock lengths (TSLs) of the knee joint at 3T. ASSESSMENT: Monoexponential, biexponential, and stretched-exponential 3D-PETRA-T1ρ parameters were measured in the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and patellar tendon (PT) by manually drawing ROIs over the entirety of the tissues. STATISTICAL TESTS: Mann-Whitney U-tests were used to compare 3D-PETRA-T1ρ parameters in the ACL, PCL, and PT between males and females. Spearman correlation coefficients were used to determine the association between age and T1ρ parameters. Statistical significance was defined as P < 0.05. RESULTS: Significant correlations with age were found the three ligaments with most of the measured T1ρ parameters (rs = 0.28-0.74) with the exception of the short fraction in the PCL (P = 0.18), and the short relaxation time in the ACL (P = 0.58) and in the PCL (P = 0.14). DATA CONCLUSION: 3D-PETRA-T1ρ can detect age-related differences in monoexponential, biexponential, and stretched-exponential T1ρ parameters in three ligaments of healthy volunteers, which are thought to be related to changes in tissue composition and structure during the aging process. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 1.

Walking with a Posterior Cruciate Ligament Injury: A Musculoskeletal Model Study.

The understanding of the changes induced in the knee's kinematics by a Posterior Cruciate Ligament (PCL) injury is still rather incomplete. This computational study aimed to analyze how the internal loads are redistributed among the remaining ligaments when the PCL is lesioned at different degrees and to understand if there is a possibility to compensate for a PCL lesion by changing the hamstring's contraction in the second half of the swing phase. A musculoskeletal model of the knee joint was used for simulating a progressive PCL injury by gradually reducing the ligament stiffness. Then, in the model with a PCL residual stiffness at 15%, further dynamic simulations of walking were performed by progressively reducing the hamstring's force. In each condition, the ligaments tension, contact force and knee kinematics were analyzed. In the simulated PCL-injured knee, the Medial Collateral Ligament (MCL) became the main passive stabilizer of the tibial posterior translation, with synergistic recruitment of the Lateral Collateral Ligament. This resulted in an enhancement of the tibial-femoral contact force with respect to the intact knee. The reduction in the hamstring's force limited the tibial posterior sliding and, consequently, the tension of the ligaments compensating for PCL injury decreased, as did the tibiofemoral contact force. This study does not pretend to represent any specific population, since our musculoskeletal model represents a single subject. However, the implemented model could allow the non-invasive estimation of load redistribution in cases of PCL injury. Understanding the changes in the knee joint biomechanics could help clinicians to restore patients' joint stability and prevent joint degeneration.

Older Age, Poor Preoperative Quadriceps Muscle Strength, and Residual Pain as Risk Factors for Poor Quadriceps Muscle Strength Recovery at 1 Year After ACL Reconstruction: A TMDU MAKS Study of 402 Patients.

Background: Poor postoperative quadriceps muscle strength recovery after anterior cruciate ligament reconstruction (ACLR) leads to delayed return to sports and lower patient satisfaction. Purpose/Hypothesis: The purpose of this study was to examine factors that affect quadriceps muscle strength 1 year after ACLR. It was hypothesized that older age, poor preoperative quadriceps muscle strength, and residual pain would be risk factors for poor quadriceps muscle strength recovery. Study Design: Case-control study; Level of evidence, 3. Methods: Included were patients from multiple institutions who underwent primary ACLR using autologous hamstring tendon grafts between August 1, 2013, and March 31, 2018, and who had at least 1 year of follow-up data. Patients with past ligamentous injuries in the affected knee, previous injuries or operations in the contralateral knee, accompanying ligament injuries of grade 2 or 3, or inflammatory or other types of osteoarthritis were excluded. Patients were categorized as having muscle strength ≥80% (good strength recovery) or <80% (poor strength recovery) compared with the contralateral leg at 1 year postoperatively. Multivariate logistic regression analysis was performed to investigate the factors influencing postoperative quadriceps muscle strength. In addition, a categorical analysis was conducted based on factors extracted by the multivariate logistic regression analysis. Results: A total of 402 patients were included. Multivariate logistic regression analysis revealed that age at surgery (P = .020), preoperative quadriceps muscle strength (P = .006), and postoperative Knee injury and Osteoarthritis Outcome Score (KOOS)-Pain score (P = .002) were significantly associated with quadriceps muscle strength at 1 year postoperatively. The odds of poor muscle strength recovery according to categorical analysis were 5.0-fold higher for patients aged >40 versus ≤20 years, 4.2-fold higher for those with preoperative quadriceps muscle index <60% versus ≥80%, and 7.7-fold higher for those with a postoperative KOOS-Pain score of <85 versus 100. Conclusion: Older age, poor preoperative quadriceps muscle strength, and low postoperative KOOS-Pain score were risk factors for poor quadriceps muscle strength 1 year after primary ACLR. Surgical indications, including age, preoperative active rehabilitation, and pain control, should be considered for optimization of postoperative quadriceps muscle strength recovery.

Injury Patterns in Posterolateral Corner Knee Injury.

Background: Posterolateral corner (PLC) knee injuries associated with different injury mechanisms are not well known. Purpose/Hypothesis: This study sought to assess the patterns of associated injuries in the setting of PLC injury. The hypothesis was that there are recognizable injury patterns in PLC injuries that may correlate with injury mechanism. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients who sustained a multiligament knee injury were retrospectively reviewed. Patients who sustained an acute grade 3 PLC injury and underwent surgery were enrolled in this study. A description of the PLC injury (location of the injury of the fibular collateral ligament [FCL], popliteus tendon, and/or popliteofibular ligament) and reported concomitant injuries (biceps femoris tendon or meniscal tears, cartilage pathology and/or peroneal nerve palsy, or bone bruises) were collected and classified based on intraoperative and magnetic resonance imaging (MRI) findings. Results: Of 135 patients reviewed, 83 did not have PLC involvement and 13 were excluded due to insufficient MRI scans available. Thus, 39 patients were included in this study. For both the anterior cruciate ligament (ACL)-PLC and ACL-posterior cruciate ligament-PLC injury patterns, the most frequent injury pattern entailed a bone bruise of the anteromedial (AM) femur and tibia, an FCL tear from the fibular head, the popliteus tendon avulsed off the femur, a biceps femoris tendon torn off the fibular head, and a common peroneal nerve palsy. Conversely, when no bone bruise occurred on the AM femur and tibia, the FCL was injured on the femoral side and the popliteus tendon, biceps femoris, and peroneal nerve were not injured. Conclusion: AM bone bruise was associated with a peroneal nerve injury in almost half of the patients, and peroneal nerve injury was not seen if there was no AM bone bruise.

Risk Factors and Outcomes for Preoperative Stiffness Requiring Intervention Before Anterior Cruciate Ligament Reconstruction.

Background: To date, there is a scarcity of literature related to the incidence of prolonged stiffness after an anterior cruciate ligament (ACL) tear that requires manipulation under anesthesia/lysis of adhesions (MUA/LOA) in the preoperative period before ACL reconstruction (ACLR) and how preoperative stiffness influences outcomes after ACLR. Hypothesis: Preoperative stiffness requiring MUA/LOA would increase the risk for postoperative stiffness, postoperative complications, and the need for subsequent procedures after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: The PearlDiver Research Program was used to identify patients who sustained an ACL tear and underwent ACLR using their respective International Classification of Diseases, 9th or 10th Revision, and Current Procedure Terminology (CPT) codes. Within this group, patients with preoperative stiffness were identified using the CPT codes for MUA or LOA. Significant risk factors for preoperative stiffness were identified through univariate and multivariate logistic regression analyses. Outcomes after ACLR were analyzed between patients with and without preoperative stiffness using multivariate logistic regression, controlling for age, sex, and Elixhauser Comorbidity Index. Results: Between 2008 and 2018, 187,071 patients who underwent ACLR were identified. Of these patients, 241 (0.13%) underwent MUA/LOA before ACLR. Patients with preoperative stiffness began preoperative physical therapy significantly later than patients without stiffness (P = .0478) and had a delay in time to ACLR (P = .0003). Univariate logistic regression demonstrated that female sex, older age, anxiety/depression, obesity, and anticoagulation use were significant risk factors for preoperative stiffness (P < .05 for all). After multivariate regression, anticoagulation use was the only independent risk factor deemed significant (odds ratio, 6.69 [95% CI, 4.01-10.51]; P < .001). Patients with preoperative stiffness were at an increased risk of experiencing postoperative stiffness, deep vein thrombosis, pulmonary embolism, surgical-site infection, and septic knee arthritis after ACLR (P < .05 for all). Conclusion: Although the risk of preoperative stiffness requiring an MUA/LOA before ACLR is low, the study findings indicated that patients with preoperative stiffness were at increased risk for postoperative complications compared with patients with no stiffness before ACLR.

Association of Tibial Tubercle-Trochlear Groove Distance With Risk of ACL Graft Failure.

Background: Limited evidence suggests a positive correlation between tibial tubercle-trochlear groove (TT-TG) distance and the risk of native anterior cruciate ligament (ACL) tear. The relationship between TT-TG distance and the risk of ACL graft failure is unknown. Hypothesis: TT-TG distance is independently associated with risk of ACL graft failure. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent ACL revision surgery between 2010 and 2018 at a single institution were identified. A control cohort underwent primary ACL reconstruction (ACLR) between 2006 and 2015, with no evidence of graft failure at 8.1 ± 2.5 years postoperatively. Record review included anthropometrics, graft type, and estimated Tegner activity score at ≥6 months after primary ACLR. Magnetic resonance imaging (MRI) scans after native ACL tear (controls) or graft failure (revision cohort) were assessed for (1) TT-TG distance, (2) proximal tibial slopes, (3) depth of tibial plateau concavity, and (4) tunnel position (revision cohort). Associations between ACL graft failure and MRI measurements, surgical variables, and patient characteristics were evaluated with logistic regression analyses. Sensitivity analyses, excluding patients with tunnel malposition, were performed to confirm multivariable results in patients with "ideal" tunnel placement. Results: Participants included 153 patients who underwent revisions and 144 controls. Controls were older than the patients who underwent revision (26.6 ± 8.8 vs 20.6 ± 7.3 years; P < .001). The mean TT-TG distance and lateral posterior tibial slope (PTS) were smaller for the control group than for the revision group (TT-TG: 9.3 ± 3.9 vs 11.2 ± 4.2 mm; P < .001; lateral PTS: 6.2° ± 3.3° vs 7.2° ± 3.6°; P = .01). TT-TG distance, lateral PTS, and age were associated with risk of ACL graft failure by multivariable analysis (OR, 1.15; 95% CI, 1.07-1.23; P < .001; OR, 1.13; 95% CI, 1.04-1.22; P = .004; and OR, 0.90; 95% CI, 0.87-0.94; P < .001, respectively). With sensitivity analyses, TT-TG distance, lateral PTS, and age at index surgery remained significantly and independently associated with ACL graft failure. Conclusion: Increased TT-TG distance, increased lateral PTS, and younger age are independently associated with increased odds of ACL graft failure. Patients with these characteristics may require a more comprehensive strategy to reduce the risk of ACL reinjury.

Long-term Outcomes of Tibial Spine Avulsion Fractures After Open Reduction With Osteosuturing Versus Arthroscopic Screw Fixation: A Multicenter Comparative Study.

Background: More information is needed regarding return to preinjury sport levels and patient-reported outcomes after tibial spine avulsion (TSA) fracture, which is most common in children aged 8 to 12 years. Purpose: To analyze return to play/sport (RTP), subjective knee-specific recovery, and quality of life in patients after TSA fracture treated with open reduction with osteosuturing versus arthroscopic reduction with internal screw fixation. Study Design: Cohort study; Level of evidence, 3. Methods: This study included 61 patients <16 years old with TSA fracture treated via open reduction with osteosuturing (n = 32) or arthroscopic reduction with screw fixation (n = 29) at 4 institutions between 2000 and 2018; all patients had at least 24 months of follow-up (mean ± SD, 87.0 ± 47.1 months; range, 24-189 months). The patients completed questionnaires regarding ability to return to preinjury-level sports, subjective knee-specific recovery, and health-related quality of life, and results were compared between treatment groups. Univariate and multivariate logistic regression analyses were conducted to determine variables associated with failure to return to preinjury level of sport. Results: The mean patient age was 11 years, with a slight male predominance (57%). Open reduction with osteosuturing was associated with a quicker RTP time than arthroscopy with screw implantation (median, 8.0 vs 21.0 weeks; P < .001). Open reduction with osteosuturing was also associated with a lower risk of failure to RTP at preinjury level (adjusted odds ratio, 6.4; 95% CI, 1.1-36.0; P = .035). Postoperative displacement >3 mm increased the risk of failure to RTP at preinjury level regardless of treatment group (adjusted odds ratio, 15.2; 95% CI, 1.2-194.9; P = .037). There was no difference in knee-specific recovery or quality of life between the treatment groups. Conclusion: Open surgery with osteosuturing was a more viable option for treating TSA fractures because it resulted in a quicker RTP time and a lower rate of failure to RTP as compared with arthroscopic screw fixation. Precise reduction contributed to improved RTP.

Influence of walking on knee ligament response in car-to-pedestrian collisions.

Pedestrians are likely to experience walking before accidents. The walking process imposes cyclic loading on knee ligaments and increases knee joint temperature. Both cyclic loading and temperature affect the material properties of ligaments, which further influence the risk of ligament injury. However, the effect of such walking-induced material property changes on pedestrian ligament response has not been considered. Therefore, in this study, we investigated the influence of walking on ligament response in car-to-pedestrian collisions. Using Total Human Model for Safety (THUMS) model, knee ligament responses (i.e., cross-sectional force and local strain) were evaluated under several crash scenarios (i.e., two impact speeds, two knee contact heights, and three pedestrian postures). In worst case scenarios, walking-induced changes in ligament material properties led to a 10% difference in maximum local strain and a 6% difference in maximum cross-sectional force. Further considering the material uncertainty caused by experimental dispersion, the ligament material property changes due to walking resulted in a 28% difference in maximum local strain and a 26% difference in maximum cross-sectional force. This study demonstrates the importance of accounting for walking-induced material property changes for the reliability of safety assessments and injury analysis.

Peroneus Longus Split Versus Semitendinosus Tendon Autograft Size: A Cross-sectional Study.

BACKGROUND: The anterior half of the peroneus longus tendon (AHPLT) has been reported to be a suitable autograft for ligament reconstruction with low donor-site morbidity. However, clinical data on graft size are limited. PURPOSE: To determine (1) if there is any difference in size between the AHPLT and semitendinosus tendon (ST) and (2) whether anthropometric measurements can predict autograft size. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 128 consecutive patients scheduled for knee ligament reconstruction were prospectively enrolled. Patients were treated with AHPLT (50%) or ST (50%). Data included anthropometric measurements and intraoperatively recorded graft size. A Student t test was used to determine differences between the groups. Bivariate correlation coefficients and multivariate regression analyses were calculated to identify relationships between graft size and anthropometric measurements. RESULTS: The AHPLT and ST groups were equally distributed according to age, sex, height, weight, and body mass index (BMI). The quadrupled graft length for the AHPLT was 7.3 ± 0.6 cm as compared with 7.5 ± 0.7 cm for the ST (P < .05). The quadrupled graft diameter was 7.7 ± 0.8 mm for the AHPLT and 8.0 ± 0.7 mm for the ST (P < .05). Height had a moderate (r = 0.57) to high (r = 0.68) correlation with AHPLT and ST length, respectively (P < .01). Weight had a moderate correlation (r = 0.43) with AHPLT diameter (P < .01) but only a weak correlation (r = 0.19) with ST diameter (P > .05). A significant interaction effect of BMI and thigh circumference on ST graft diameter was found, which showed that the effect of thigh circumference on ST graft diameter decreased significantly as BMI increased (P < .05). This moderating effect of BMI could not be observed for the coefficient of shank circumference on AHPLT graft diameter (P > .05). CONCLUSION: (1) The peroneus longus split tendon provides a reliable autograft size for knee ligament reconstructions. It was prone to be slightly shorter and thinner than the ST. (2) Patient height was the strongest predictor for AHPLT and ST graft length. However, predicting graft diameter based on thigh or shank circumference was more challenging, with higher BMIs affecting the ability to predict ST more than AHPLT.

External Validation of the KOOS-ACL in the MOON Group Cohort of Young Athletes Followed for 10 Postoperative Years.

BACKGROUND: The Knee injury and Osteoarthritis Outcome Score-Anterior Cruciate Ligament (KOOS-ACL) is a short form version of the KOOS, developed to target populations of young active patients with ACL tears. The KOOS-ACL consists of 2 subscales: Function (8 items) and Sport (4 items). The KOOS-ACL was developed and validated using data from the Stability 1 study from baseline to postoperative 2 years. PURPOSE: To validate the KOOS-ACL in an external sample of patients matching the outcome's target population. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 1. METHODS: The Multicenter Orthopaedic Outcomes Network group cohort of 839 patients aged 14 to 22 years who tore their ACLs while playing sports was used to assess internal consistency reliability, structural validity, convergent validity, responsiveness to change, and floor/ceiling effects of the KOOS-ACL at 4 time points: baseline and postoperative 2, 6, and 10 years. Detection of treatment effects between graft type (hamstring tendon vs bone-patellar tendon-bone) were also compared between the full-length KOOS and KOOS-ACL. RESULTS: The KOOS-ACL demonstrated acceptable internal consistency reliability (α = .82-.89), structural validity (Tucker-Lewis index and comparative fit index = 0.98-0.99; standardized root mean square residual and root mean square error of approximation = 0.04-0.07), convergent validity (Spearman correlation with International Knee Documentation Committee subjective knee form = 0.66-0.85; Western Ontario and McMaster Universities Osteoarthritis Index function = 0.84-0.95), and responsiveness to change across time (large effect sizes from baseline to postoperative 2 years; d = 0.94 [Function] and d = 1.54 [Sport]). Stable scores and significant ceiling effects were seen from 2 to 10 years. No significant differences in KOOS or KOOS-ACL scores were detected between patients with different graft types. CONCLUSION: The KOOS-ACL shows improved structural validity when compared with the full-length KOOS and adequate psychometric properties in a large external sample of high school and college athletes. This strengthens the argument to use the KOOS-ACL to assess young active patients with ACL tears in clinical research and practice.

Development and Preliminary Validation of the KOOS-ACL: A Short Form Version of the KOOS for Young Active Patients With ACL Tears.

BACKGROUND: The Knee injury and Osteoarthritis Outcomes Score (KOOS) is a widely used region-specific outcome measure for assessing patients of all ages with a variety of knee conditions. Use of the KOOS for young active patients with anterior cruciate ligament (ACL) tear has been called into question regarding its relevance and interpretability for this specific population. Furthermore, the KOOS does not have adequate structural validity for use in high-functioning patients with ACL deficiency. PURPOSE: To develop a condition-specific short form version of the KOOS that is appropriate for the young active population with ACL deficiency: the KOOS-ACL. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: A baseline data set of 618 young patients (≤25 years old) with ACL tears was divided into development and validation samples. Exploratory factor analyses were conducted in the development sample to identify the underlying factor structure and to reduce the number of items based on statistical and conceptual indicators. Confirmatory factor analyses were conducted to check fit indices of the proposed KOOS-ACL model in both samples. Psychometric properties of the KOOS-ACL were assessed using the same data set, expanded to include patient data from 5 time points (baseline and postoperative 3, 6, 12, and 24 months). Internal consistency reliability, structural validity, convergent validity, responsiveness to change, floor/ceiling effects, and detection of treatment effects between surgical interventions (ACL reconstruction alone vs ACL reconstruction + lateral extra-articular tenodesis) were assessed. RESULTS: A 2-factor structure was deemed most appropriate for the KOOS-ACL. Of 42 items, 30 were removed from the full-length KOOS. The final KOOS-ACL model showed acceptable internal consistency reliability (α = .79-.90), structural validity (comparative fit index and Tucker-Lewis index = 0.98-0.99; root mean square error of approximation and standardized root mean square residual = 0.04-0.07), convergent validity (Spearman correlation with International Knee Documentation Committee subjective knee form = 0.61-0.83), and responsiveness across time (significant small to large effects; P < .05). CONCLUSION: The new KOOS-ACL questionnaire contains 12 items and 2 subscales-Function (8 items) and Sport (4 items)-relevant to young active patients with an ACL tear. Use of this short form would reduce patient burden by more than two-thirds; it provides improved structural validity as compared with the full-length KOOS for our population of interest; and it demonstrates adequate psychometric properties in our sample of young active patients undergoing ACL reconstruction.