High Rate of Concomitant Lumbo-Sacral Spine Pathology in the Setting of Hip Abductor Tendon Repair.

BACKGROUND: Hip abductor deficiency is a common cause of lateral hip pain in middle-aged patients. Identifying upstream muscle denervation originating in the lumbo-sacral spine could potentially impact the management of patients who have abductor deficiency. The purpose of this study was to estimate the prevalence of lumbo-sacral pathology (L4 to S1) in patients undergoing hip abductor tendon repair. METHODS: All cases of primary hip abductor repair performed at a tertiary care center between January 2010 and December 2021 were reviewed. Patients were classified into the following groups: A) confirmed L4 to S1 disease based on preoperative or perioperative L4 to S1 interventions (ie, surgery, epidural injections, and/or positive electromyography findings); B) radiographic evidence on lumbar spine magnetic resonance imaging demonstrating nerve compression at L4 to S1; and C) no evidence of L4 to S1 disease. RESULTS: There were 131 cases of primary hip abductor repair that were included. Over 80% of patients were women, who had a mean age of 64 years (range, 20 to 85). There were thirteen patients (9.9%) who underwent concomitant total hip arthroplasty (THA). Of the included patients, 29% (n = 38) were categorized into group A, 12% (n = 16) into group B, and 59% (n = 77) into group C. Patients who had L4 to S1 pathology were older than patients who did not have L4 to S1 pathology (67 versus 61 years, P = .004). Of the patients undergoing concomitant THA and hip abductor repair, 54% demonstrated evidence of lumbo-sacral spine pathology. CONCLUSIONS: Over 40% of patients undergoing isolated hip abductor tendon repair and >50% of patients undergoing concomitant hip abductor tendon repair and THA demonstrated evidence of L4 to S1 disease perioperatively. Patients demonstrating symptomatic hip abductor deficiency should be screened for concomitant lower lumbo-sacral spine pathology.

Establishing minimal detectable change thresholds for the international knee documentation committee and Kujala scores at one and two years after patellofemoral joint arthroplasty.

PURPOSE: To define the minimal detectable change (MDC) for the international knee documentation committee (IKDC) and Kujala scores one and two years after patellofemoral joint arthroplasty (PFA). METHODS: A distribution-based method (one-half the standard deviation of the mean difference between postoperative and preoperative outcome scores) was applied to establish MDC thresholds among 225 patients undergoing primary PFA at a single high-volume musculoskeletal-care center. Stability of change in MDC achievement was explored by quantifying the proportion of achievement at one- and two-year postoperative timepoints. Multivariable logistic regression analysis was performed to explore the association between sociodemographic and operative features on MDC achievement. RESULTS: MDC thresholds for the Kujala score were 10.3 (71.1% achievement) and 10.6 (70.4% achievement) at one- and two years, respectively. The MDC thresholds for the IKDC score were 11.2 (78.1% achievement) and 12.3 (69.0% achievement) at one- and two years, respectively. Predictors of achieving the MDC for the Kujala and IKDC scores at both time points were lower preoperative Kujala and IKDC scores, respectively. Preoperative thresholds of ≤ 24.1 and 7.6 for the Kujala and IKDC scores, respectively, were associated with a 90% MDC achievement probability. When preoperative thresholds approached 64.3 and 48.3 for the Kujala and IKDC, respectively, MDC achievement probability reduced to 50%. CONCLUSION: The MDC thresholds for the Kujala and IKDC scores two years after PFA were 10.6 and 12.3, respectively. Clinically significant health status changes were maintained overall, with a slight decrease in achievement rates between one and two years. MDC achievement was associated with disability at presentation, and several probability-based preoperative thresholds were defined. These findings may assist knee surgeons with patient selection and the decision to proceed with PFA by better understanding the patient-specific propensity for MDC achievement. LEVEL OF EVIDENCE: IV, retrospective case series.

High degree of alignment precision associated with total knee arthroplasty performed using a surgical robot or handheld navigation.

PURPOSE: The purpose of this study was to compare the precision of bony resections during total knee arthroplasty (TKA) performed using different computer-assisted technologies. METHODS: Patients who underwent a primary TKA using an imageless accelerometer-based handheld navigation system (KneeAlign2®, OrthAlign Inc.) or computed tomography-based large-console surgical robot (Mako®, Stryker Corp.) from 2017 to 2020 were retrospectively reviewed. Templated alignment targets and demographic data were collected. Coronal plane alignment of the femoral and tibial components and tibial slope were measured on postoperative radiographs. Patients with excessive flexion or rotation preventing accurate measurement were excluded. RESULTS: A total of 240 patients who underwent TKA using either a handheld (n = 120) or robotic (n = 120) system were included. There were no statistically significant differences in age, sex, and BMI between groups. A small but statistically significant difference in the precision of the distal femoral resection was observed between the handheld and robotic cohorts (1.5° vs. 1.1° difference between templated and measured alignments, p = 0.024), though this is likely clinically insignificant. There were no significant differences in the precision of the tibial resection between the handheld and robotic groups (coronal plane 0.9° vs. 1.0°, n.s.; sagittal plane 1.2° vs. 1.1°, n.s.). There were no significant differences in the rate of overall precision between cohorts (n.s.). CONCLUSIONS: A high degree of component alignment precision was observed for both imageless handheld navigation and CT-based robotic cohorts. Surgeons considering options for computer-assisted TKA should take other important factors, including surgical principles, templating software, ligament balancing, intraoperative adjustability, equipment logistics, and cost, into account. LEVEL OF EVIDENCE: III.

Proximal bone block with distal screw trajectory improves mechanical stability during distalization tibial tubercle osteotomy.

PURPOSE: The purpose of this study was to quantify differences in mechanical stability of a wedge-shaped distalization tibial tubercle osteotomy (TTO) with a standard technique, versus a modified technique with use of a proximal bone block and distally angled screw trajectory. METHODS: Ten fresh-frozen cadaver lower extremity specimens (five matched pairs) were utilized. Within each specimen pair, one specimen was randomly assigned to undergo a standard distalization osteotomy fixed with two bicortical 4.5-mm screws oriented perpendicular to the long axis of the tibia, and the other to undergo a distalization osteotomy with modified fixation utilizing a proximal bone block and distally angled screw trajectory. Each specimen's patella and tibia were mounted on a servo-hydraulic load frame using custom fixtures (MTS Instron). The patellar tendon was dynamically loaded to 400 N at a rate of 200 N/second for 500 cycles. Following the cyclic loading, loading to failure was done at 25 mm/min. RESULTS: The modified distalization TTO technique demonstrated significantly higher average load to failure compared to the standard distalization TTO technique (1339 N vs. 844.1 N, p < 0.001). Average maximum tibial tubercle displacement during cyclic loading was significantly smaller in the modified TTO technique group compared to the standard TTO technique (1.1 mm vs. 4.7 mm, p < 0.001). CONCLUSION: This study demonstrates that distalization TTO utilizing a modified technique with a proximal bone block and distally aimed screws is biomechanically superior to standard distalization TTO without proximal bone block and screw trajectory perpendicular to the long axis of the tibia. This increased stability may aid in reducing the reported higher complication rates (including loss of fixation, delayed union and nonunion) following distalization TTO, although future clinical outcome studies are warranted.

Magnetic Resonance Imaging Findings of Core Muscle Injuries in High Level Athletes.

ABSTRACT: Core muscle injuries are common injuries in athletes involved in high speed side-to-side acceleration movements. The term core muscle injury encapsulates several different injuries that occur in the pelvic region that have similar presentations. Along with a good history and physical examination, magnetic resonance imaging (MRI) can be a helpful tool in the diagnostic process. Correct orientation and protocols are needed to show the correct anatomy with an MRI. Furthermore, to determine the exact etiology of the core muscle injury, it is important to know which structures are likely to be involved and be able to recognize the patterns of injury on imaging.

Juvenile Osteochondritis Dissecans of the Trochlea: A Cohort Study of 34 Trochlear Lesions Associated With Sporting Activities That Load the Patellofemoral Joint.

BACKGROUND: Juvenile osteochondritis dissecans (JOCD) lesions are rarely located in the trochlea and few studies have focused on the causes and outcomes of JOCD lesions in this part of the knee. The purpose of this study is to (1) evaluate the clinical characteristics and outcomes of patients who undergo surgery for JOCD in this unusual location as well as (2) assess the association between trochlear JOCD and participation in sporting activities that load the patellofemoral joint. METHODS: We conducted a retrospective cohort study of 34 trochlear JOCD lesions in 30 patients. Cases that involved traumatic cartilage shear or patella instability were excluded. Preoperative and postoperative magnetic resonance images and x-rays were evaluated and demographic data, sports played, comorbidities, surgical procedures, and clinical data were extracted from medical records. A case-control cohort of 102 femoral condyle lesions was used to assess the correlation between sports played and lesion location. RESULTS: The cohort comprised 34 consecutive trochlear JOCD lesions in 30 patients (26 males, 4 females). Average age at surgery was 13.8 years (9.3 to 18.0 y). In total, 27 (90%) patients were active, and of these active patients, soccer and basketball were the most common sports played. In the case-control comparison, the correlation between playing either basketball or soccer and the presence of a trochlear JOCD lesion was statistically significant (P=0.017). In total, 21 knees (62%) received operative treatment. Sixteen of the surgical patients underwent repair and fixation with bioabsorbable nails. The average length of clinical and radiographic follow-up was 21.1 months. All patients who underwent fixation showed radiographic and/or clinical indications of healing at most recent follow-up. Thirteen of the patients who underwent fixation were active, and all of these patients reported successful return to sports. Thirteen knees underwent nonoperative treatment, and the majority of these patients had limited follow-up. CONCLUSIONS: We report a significant association between pediatric athletes who play basketball and soccer and the development of trochlear JOCD, suggesting that repetitive loading of the patellofemoral joint may play a role in the development of JOCD lesions. Patients with trochlear JOCD lesions were likely to undergo surgery, and repair and fixation of the lesions produced good outcomes at short-term follow-up. LEVEL OF EVIDENCE: Level III-case-control study.

Medial patellofemoral ligament (MPFL) reconstruction technique using an epiphyseal femoral socket with fluoroscopic guidance helps avoid physeal injury in skeletally immature patients.

PURPOSE: The purpose of this study was to assess the physeal safety associated with the use of an epiphyseal femoral socket for paediatric medial patellofemoral ligament (MPFL) reconstruction. METHODS: Fifty-four knees in 49 skeletally immature patients underwent physeal-sparing MPFL reconstruction performed by 1 surgeon at a tertiary care academic medical centre from 2007 to 2016. A femoral socket distal to the femoral physis was used for graft fixation in all the patients. To assess physeal safety, all included patients either had post-operative MRIs of the operative knee or standing hip-to-ankle radiographs. Physeal safety was assessed on MRI, and the distance between the femoral socket relative to the physis was measured at both the aperture and the end of the socket. Development of lower limb angular deformities and/or limb length discrepancy (LLD) was evaluated using post-operative standing hip-to-ankle radiographs, patient records, and clinical assessments. RESULTS: The mean age at time of surgery was 13.3 ± 1.6 years. The median length of radiographic follow-up was 2.2 years (range 1.0-5.7 years). At most recent clinical follow-up, five patients (9.3%) had recurrent patellar instability, with three patients (5.6%) undergoing subsequent tibial tubercle osteotomy or revision MPFL reconstruction. There was no statistically significant difference in leg length between operated and non-operated extremities (n.s.). There was no statistically significant difference between non-operated and operated mMPTA (n.s.) and mLDFA (n.s.) measurements. On post-operative MRI, there was no evidence of physeal arrest. The median distance from the physis to the socket at the aperture and distal end of the femoral socket were 5.9 mm (range 1.9-12) and 7.1 mm (1.3-12.4), respectively. CONCLUSION: These results demonstrate that with fluoroscopic guidance, placing the femoral socket distal to the distal femoral physis is an effective method for avoiding physeal injury and subsequent growth disturbances in children with patellar instability. Clinically, this information is essential in optimal surgical management of these patients, as this technique allows for femoral fixation of the MPFL reconstruction graft within the epiphysis while also preserving normal growth. LEVEL OF EVIDENCE: Level IV-case series.

Decline in clinical scores at long-term follow-up of arthroscopically treated discoid lateral meniscus in children.

PURPOSE: The purpose of this study was to examine the long-term clinical outcomes of arthroscopic partial meniscectomy for the treatment of discoid lateral meniscus in children. METHODS: A previous study identified 34 consecutive patients that underwent arthroscopic meniscal saucerization by one of the two surgeons between 1997 and 2002. Patients were asked to complete several outcomes questionnaires and were given the opportunity to receive a knee exam performed by their treating surgeon. RESULTS: Of the 34 eligible patients, 21 agreed to participate. Seventeen patients (19 knees) had greater than 2-year follow-up, with an average follow-up of 11.0 years (range 3.4-16.6 years). Average age at the time of surgery was 9.3 years. Average IKDC, Kujala, and Lysholm scores at follow-up were 82.8 ± 28.9, 86.6 ± 15.2, and 83.7 ± 18.6, respectively. In addition, median Marx and Tegner scores were 5 (range 0-14) and 6 (range 3-8), respectively. Stratifying the Lysholm scores revealed outcomes that were 45.4% "excellent", 16.7% "good", 25.0% "fair", and 16.7% "poor". In total, 36.8% (7 of 19) of knees underwent at least one subsequent surgical procedure. There were no significant associations between outcome scores and discoid type, meniscal stability, location of instability, or age at time of surgery. CONCLUSIONS: The results of the current study suggest that clinical outcome scores decline over time in patients treated arthroscopically for symptomatic discoid meniscus. Compared to our previous study with 2-year follow-up, there is an increased incidence of knee pain and mechanical/functional limitations. The overall modest, long-term results of this study illustrate the need for improved operative treatments for symptomatic discoid meniscus in children to prevent progressive, long-term clinical decline in these patients.

Radiographic Results and Complications of 3 Guided Growth Implants.

BACKGROUND: Temporary, implant-mediated hemiepiphysiodesis (ie, guided growth) is an effective and popular treatment method for lower extremity angular deformities. The purpose of this study was to retrospectively evaluate the safety profile of 3 different implants used to correct lower extremity angular deformities in pediatric patients. METHODS: We retrospectively reviewed a consecutive series of pediatric patients with lower extremity angular deformities who underwent implant-mediated guided growth by 2 surgeons at our institution between 2004 and 2014. Implants were selected according to surgeon preference and included the Biomet peanut plate, Orthofix eight-plate, and Pega Medical hinge plate. Medical records and radiographs were reviewed to assess deformity correction, implant integrity, and complications. RESULTS: During the study period, 115 plates (63 Biomet peanut plates, 30 Orthofix eight-plates, and 22 Pega Medical hinge plates) were implanted in 52 patients (24 males, 28 females). Average age at implantation was 11.7 years (12.3 y in males, 11.1 y in females). Average length of follow-up was 18.4 months. There was no significant difference in rate of deformity correction between the implant types (P=0.08).Three broken screws (2.6%) were observed, all of which involved cannulated screws in peanut plates. Four peanut plates (6.3%) had an implant-related complication: 3 broken screws and 1 screw pullout. Three eight-plates (10.0%) had screw pullout. No complications were observed within either the hinge plate or solid screw groups. Implant-related complications were significantly associated with increased body weight and cannulated screw use (P=0.02 and 0.03, respectively), but not bone age, sex, plate type, or rate of deformity correction. No deep infections, premature growth arrests, or plate breakages were observed. CONCLUSIONS: Implant-mediated guided growth is a safe technique for pediatric lower extremity angular deformity correction with a low complication rate. This study demonstrated that overweight patients had a significantly higher rate of implant-related complications. Screw breakages were only observed with cannulated screws in peanut plates. Thus, we recommend using solid, noncannulated screws in overweight children who are at an increased risk of implant failure. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Classification and assessment of juvenile osteochondritis dissecans knee lesions.

PURPOSE OF REVIEW: Juvenile osteochondritis dissecans (JOCD) knee lesions are common abnormalities in adolescents and children, and have higher rates of spontaneous healing with nonoperative management compared to adult osteochondritis dissecans (OCD) lesions. Multiple classification and assessment systems have been established in order to help clinicians determine which lesions are amenable to nonoperative management. However, these assessments often use adult OCD classification systems of lesion stability, which have poor reliability in JOCD lesions. The purpose of this review is to assess these various classification systems proposed for JOCD lesions. RECENT FINDINGS: Although arthroscopy remains the gold standard for the definitive assessment of lesion stability, recent evidence suggests that MRI characteristics indicative of instability in adult OCD lesions are not applicable in determining JOCD lesion instability. In addition, the correlation between arthroscopic and MRI indications of instability is highly varied in these younger patients. SUMMARY: In order for the pediatric orthopedic surgeon to more accurately predict treatment outcomes in patients with JOCD knee lesions, further investigation into the radiographic characteristics specific to JOCD lesion instability and healing is warranted.

The tibial eminence fracture in skeletally immature patients.

PURPOSE OF REVIEW: Although tibial eminence fractures are uncommon, their importance cannot be overemphasized in skeletally immature patients because of the fracture's close proximity to both the tibial physis as well as the attachment between the tibial eminence and the anterior cruciate ligament, the latter being a key component in maintaining knee stability. This review focuses on recent trends in treatment concepts and devices. RECENT FINDINGS: Recent literature on this topic addresses the existence of a variety of treatment modalities, but the majority of these articles analyzed a limited number of cases and insisted on the merits of their own methods. Nevertheless, some consensus has been reached regarding treatment direction and how much laxity should be considered acceptable. SUMMARY: Although the review failed to reveal a gold standard modality in treating tibial eminence fractures, most studies agreed on several issues. Displaced intra-articular fractures should be fixed operatively.

Combined Medial Quadriceps Tendon-Femoral Ligament and Medial Patellofemoral Ligament Reconstruction for Revision Patellofemoral Soft-Tissue Stabilization.

Patients with recurrent patellofemoral instability in whom prior medial patellofemoral ligament (MPFL) reconstruction fails present unique challenges for revision soft-tissue stabilization owing to scar tissue formation, limited patellar bone stock for anchor placement, and increased risk of patellar fracture. We describe a technique for revision patellofemoral soft-tissue stabilization that combines MPFL and medial quadriceps tendon-femoral ligament reconstruction techniques through combined fixation to the patella with 1 suture anchor and soft-tissue fixation to the quadriceps tendon. The proposed technique maximizes restoration of resistance to lateral translation by attempting to re-create the native MPFL attachment and minimizes patellar fracture risk in the setting of poor bone stock through the use of a single 1.8-mm all-suture suture anchor rather than bone tunnels or multiple anchor placement for bony fixation.

Magnetic Resonance Imaging Patterns of Common Injuries in Pediatric and Adolescent Athletes.

Injuries in pediatric and adolescent athletes continue to rise in the United States, with increases in year-round sports participation, earlier sport specialization, and inadequate access to neuromuscular training programs. In this setting, the use of magnetic resonance imaging (MRI) provides a critical diagnostic tool. This review article describes the utility of MRI in diagnosing common pediatric and adolescent sports injuries and presents imaging findings associated with these pathologies.

Incidence of Complications After Tibial Tubercle Osteotomy and Tibial Tubercle Osteotomy With Distalization.

BACKGROUND: Tibial tubercle osteotomy (TTO) is a well-established surgical treatment option for patellofemoral instability and pain. TTO with distalization (TTO-D) is indicated for patients with patellofemoral instability, patellar malalignment, and patella alta. The current literature demonstrates several complications that may be associated with TTO, with reportedly higher rates of complications associated with TTO-D. PURPOSE: To analyze and compare complication rates after TTO without distalization (TTO-ND) and TTO-D and assess risk factors associated with complications. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All skeletally mature patients who underwent TTO with or without distalization by a single surgeon between September 2014 and May 2023 with a minimum of 6 months of clinical follow-up were retrospectively reviewed. Patient factors, surgical indications, perioperative data, and complications were collected via a retrospective review of electronic medical records. Concomitant procedures were categorized as intra-articular, extra-articular, and osteotomies. RESULTS: A total of 251 TTOs (117 TTO-D, 134 TTO-ND) were included in the study group. Postoperative complications were observed in 15 operations (6%), with arthrofibrosis as the most common complication (10 operations [4%]). TTO-D and TTO-ND had similar rates of complication (5% vs 7%; P = .793). Clinical nonunion was observed in 3 operations (3%) in the TTO-D cohort and 1 operation (1%) in the TTO-ND cohort. In the TTO-D cohort, concomitant intra-articular procedures were significantly associated with an increased likelihood of complications in a univariate model. In the TTO-ND cohort, an increased tourniquet time was significantly associated with an increased likelihood of complications in a univariate model. For all TTOs as well as the TTO-D and TTO-ND cohorts, there were no significant associations between patient or surgical variables in a multivariate model. CONCLUSION: TTO with and without distalization is a safe procedure with low rates of complication. TTO-D was not associated with a higher rate of complications compared with TTO-ND. There was no association between complications and surgical variables for TTO procedures.

Decreased Effective Patellar Tendon Length following Distalization Tibial Tubercle Osteotomy without Patellar Tendon Tenodesis.

Background: Distalization tibial tubercle osteotomy (TTO) is an effective treatment for improving patellar height in patients with patella alta associated with patellofemoral instability and cartilage lesions. The addition of a patellar tendon tenodesis has been suggested; nonetheless, concerns exist regarding possible increased patellofemoral cartilage stresses. Purpose: To evaluate pre- and postoperative patellar tendon length and alignment parameters on magnetic resonance imaging (MRI), as well as patient-reported outcome measures (PROMs) after distalization TTO without patellar tendon tenodesis. Study Design: Case series; Level of evidence, 4. Methods: Twenty skeletally mature patients who underwent distalization TTO with or without anteromedialization at our institution between December 2014 and August 2021 were included. All patients underwent pre- and postoperative MRIs of the affected knee. The Caton-Deschamps index (CDI), the axial and sagittal tibial tubercle-trochlear groove (TT-TG) distances, the distances from the tibial plateau to the patellar tendon insertion and the tibial tubercle, and the patellar tendon length were assessed. PROMs included the International Knee Documentation Committee Subjective Knee Evaluation Form, the Knee injury and Osteoarthritis Outcome Score-Quality of Life subscale, the Kujala Anterior Knee Pain Scale, and the Veterans RAND 12-Item Health Survey mental and physical component scores. Results: The mean patient age at surgery was 27.4 years (range, 14-42 years). Radiographic parameters demonstrated improved patellar height (CDI decreased from 1.36 to 1.11; P < .001) after distalization TTO. The distance from the tibial plateau to the patellar tendon insertion significantly decreased from 20.1 mm preoperatively to 17.9 mm postoperatively (P < .020), and the patellar tendon length decreased from 53.4 mm preoperatively to 46.0 mm postoperatively (P < .001). The patellar tendon insertion was not distalized after distalization TTO, likely because of scarring of the patellar tendon proximal to the osteotomy site. Patients demonstrated significant pre- to postoperative improvements on all PROMs (P≤ .024 for all ). There were 4 (20%) complications-2 cases of arthrofibrosis, 1 postoperative infection, and 1 osteotomy delayed union. Conclusion: Distalization TTO without patellar tendon tenodesis was associated with improved radiographic outcomes and PROMs. It provides an additional tool for surgical management of patellofemoral pathology with associated patella alta.

An ultrastructure analysis of the developing human anterior cruciate ligament tibial enthesis.

This study aimed to investigate the ultrastructural anatomy of the developing ACL tibial enthesis. We hypothesized that enthesis architecture would progressively mature and remodel, eventually resembling that of the adult by the early postnatal stage. Five fresh-frozen human pediatric cadaveric knees aged 1-36 months underwent anatomical dissection to harvest the ACL insertion and underlying tibial chondroepiphysis. The samples were prepared for scanning electron microscopy (SEM) to examine the ultrastructural anatomy of the enthesis and underwent histological staining for circular polarized light (CPL) and light microscopy imaging. SEM analysis of the 1- and 8-month-old samples revealed a shallow interdigitation between the dense fibrous (ligamentous) tissue and unmineralized chondrogenic tissues, with a minimal transition zone. By 11-month, a more complex transition zone was present. By age 19- and 36-month-old, a progressively more complex and defined fibrocartilage zone was observed. CPL analysis revealed distinct collagen fiber continuity, alignment, and organization changes over time. By 19 and 36 months, the samples exhibited complex fiber arrangements and a progression toward uniform fiber orientation. Similarly, histological analysis demonstrated progressive remodeling of the enthesis with increasing age. Our results suggest that the ACL enthesis of the developing knee begins to mimic that of an adult as early as 19 months of age, as a more complex transition between ligamentous and chondro-epiphyseal tissue can be appreciated. We hypothesize that the observed changes are likely due to mechanical loading of the enthesis with the onset of weightbearing. Future investigations of ACL reconstruction and repair will benefit from improved understanding of the chondro-epiphyseal/ACL regions.

Risk Factors for Atraumatic Medial Patellar Facet Lesions.

Background: Medial patellar facet lesions have been well-described in the setting of patellar instability. However, relatively little is known about risk factors for atraumatic medial patellar facet lesions. Purpose/Hypothesis: To identify clinical and radiographic risk factors for medial patellar facet lesions in patients without a history of trauma or patellar instability. It was hypothesized that a posterior tibial tubercle relative to the trochlear groove would be a risk factor for atraumatic medial patellar facet lesions. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 37 patients with atraumatic medial patellar facet lesions were matched by age, sex, and body mass index with 37 control patients without a history of patellofemoral dysplasia. Demographic and imaging characteristics were compared between groups. Plain radiography was used to evaluate Wiberg type, and magnetic resonance imaging was used to calculate Caton-Deschamps index, tibial tubercle-trochlear groove distance, trochlear facet asymmetry ratio, patellotrochlear index, sulcus depth, patellar bisect ratio, and tibial tubercle height. Statistically significant variables from univariate analysis were used as inputs to the multivariate regression model to assess independent risk factors. Results: There were no differences between groups with respect to Wiberg type, Caton-Deschamps index, tibial tubercle-trochlear groove distance, sulcus depth, or patellotrochlear index (P > .05 for all). The medial facet lesion group had a larger medial trochlear facet (trochlear facet asymmetry ratio, 0.72 ± 0.11 vs 0.60 ± 0.09; P < .001), a more medial-lying patella in the trochlear groove (patellar bisect ratio, 0.57 ± 0.06 vs 0.55 ± 0.07; P = .035), and a more posterior tibial tubercle relative to the trochlear groove (tibial tubercle height, -3.13 ± 5.21 vs -0.23 ± 5.93 mm; P = .030) compared with the control group. Multivariate regression analysis identified trochlear facet asymmetry and tibial tubercle height as independent risk factors for medial patellar facet lesions (relative risk = 97.3 [95% CI, 14.9-635.1], P < .001 and relative risk = 0.95 [95% CI, 0.92-0.98], P = .004, respectively). Conclusion: A relatively larger medial trochlear facet and a more posterior tibial tubercle relative to the trochlear groove were found to be risk factors for medial patellar facet lesions in patients without a history of trauma or patellar instability.

Medial Meniscus Posterior Root Tears Lead to Changes in Joint Contact Mechanics at Low Flexion Angles During Simulated Gait.

BACKGROUND: Previous biomechanical studies evaluating medial meniscus posterior root tears (MMPRTs) are limited to low loads applied at specified loading angles, which cannot capture the effects of MMPRTs during the multidirectional forces and moments placed across the knee during physiological activities. PURPOSE: To quantify the effects of MMPRTs on knee joint contact mechanics during simulated gait. STUDY DESIGN: Controlled laboratory study. METHODS: Six human cadaveric knees were mounted on a robotic simulator programmed to apply dynamic forces, moments, and flexion angles to mimic level walking. Twelve cycles of multidirectional and dynamic standard gait input waveforms, normalized to specimen-specific body weight, were applied to the following conditions: (1) native, intact meniscus and (2) MMPRT. Peak contact stress, contact area, and the position of the weighted center of contact across the medial tibial plateau throughout the stance phase of gait were quantified using an electronic sensor placed across the medial tibial plateau. The difference between the intact state and MMPRT condition was calculated for each metric, and then the means and 95% CIs were computed. RESULTS: Despite heterogeneity in knee contact forces, MMPRTs significantly increased peak contact stress by a mean of 2 MPa across 20% to 37% of the simulated gait cycle and significantly decreased the contact area by a mean of 200 mm2 across 16% to 60% of the simulated gait cycle in comparison with the native state. There was no significant difference in the position of the weighted center of contact, in either the anterior-posterior or medial-lateral directions, after MMPRT. CONCLUSION: MMPRTs led to both a significant increase in peak contact stress and decreased contact areas for a portion of the simulated gait cycle ranging from 20% to 37% of gait, during which time the femur was flexed <15°. CLINICAL RELEVANCE: Contact mechanics are significantly affected after MMPRTs during early to midstance and at knee flexion angles lower than demonstrated previously. These data provide further biomechanical justification for treating MMPRTs.

Quadriceps Tendon Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: 3-Year Clinical and Patient-Reported Outcomes.

BACKGROUND: The rate of anterior cruciate ligament (ACL) rupture in active, skeletally immature patients is increasing. Although hamstring tendon autograft (HTA) was previously deemed the gold standard, recent studies have shown HTA to have a high failure rate in this high-risk population of young competitive athletes, and quadriceps tendon autograft (QTA) has yielded excellent preliminary outcomes in some studies examining this population. PURPOSE: To evaluate 3-year clinical and patient-reported functional outcomes of primary ACL reconstruction (ACLR) with soft tissue QTA in skeletally immature patients. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Skeletally immature patients who underwent ACLR with a full-thickness soft tissue QTA were included. Preoperative patient and surgical data were collected. The ACLR technique was selected predicated upon skeletal age and included all-epiphyseal and complete transphyseal techniques. Patients were followed for a minimum of 2 years with successive clinical visits or were contacted via telephone. Patients who did not have minimum 2-year follow-up after 3 contact attempts via telephone were excluded. Information regarding return to sports (RTS) and concomitant or subsequent surgical procedures was collected. Pediatric International Knee Documentation Committee (Pedi-IKDC), Hospital for Special Surgery Functional Activity Brief Scale (HSS Pedi-FABS), and Single Assessment Numeric Evaluation (SANE) scores were collected. RESULTS: Of 85 adolescent patients aged 11.1 to 17.6 years (mean age, 14.1 ± 1.2 years), 2 patients were determined to be lost to follow-up after 3 failed contact attempts. Of the patients included in this study (N = 83), 26 patients (31%) underwent all-epiphyseal and 57 patients (69%) underwent complete transphyseal ACLR. Additionally, 48 patients (58%) underwent concomitant lateral extra-articular tenodesis using the iliotibial band with a modified Lemaire technique. The mean follow-up time was 3.7 ± 1.2 years (range, 2-7 years). Twenty (24%) patients had subsequent surgical procedures, of which 3 (4%) were due to graft failures. At a mean 3-year follow-up, the mean Pedi-IKDC, HSS Pedi-FABS, and SANE scores were 90, 23, and 94 respectively; the RTS rate was 100%; and the rate of RTS at the previous level of performance was 93%. CONCLUSION: Use of a soft tissue QTA for ALCR in a high-risk skeletally immature population of athletes resulted in excellent postoperative outcomes with low rates of graft failure and high return to sport rates.

Rare Fracture Knee Dislocation Treated with Ligament Repair and Novel Arcuate Fracture Repair Technique: A Case Report.

CASE: A 57-year-old man presented with a left knee dislocation after a motor vehicle collision. Clinical and imaging evaluation demonstrated disruption of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), anterolateral ligament (ALL), and posterolateral corner (PLC). The patient underwent acute, single-stage arthroscopic primary ACL and PCL repair, with arcuate fracture fixation using a novel technique. At 4 years postoperatively, he continues to do well subjectively with minimal clinical laxity. CONCLUSION: Acute, single-stage arthroscopic primary ligamentous repair is a viable option for high-grade multiligamentous knee dislocations and may be combined with our novel technique for arcuate fracture fixation. LEVEL OF EVIDENCE: Level IV, Case Report.