Background: The medial patellofemoral ligament (MPFL) has been recognized as the primary restraint to lateral subluxation of the patella. Reconstruction of the MPFL for patellar instability has demonstrated early clinical success, but postoperative complications have rarely been reported, especially in young patients. Purpose: To assess early complications (<3 years) of MPFL reconstruction in young patients. Study Design: Case series; Level of evidence, 4. Methods: The charts and radiographs of all patients who underwent MPFL reconstruction between 2005 and 2011 were retrospectively reviewed to identify postoperative complications. A complication was considered major if the patient required hospitalization or further surgery. Each complication was analyzed to identify the technical factors related to it. Results: A total of 179 knees underwent MPFL reconstruction during the study period. There were 38 complications in 29 knees (16.2%), with 34 major and 4 minor. Major complications included recurrent lateral patellar instability (8 patients), knee motion stiffness with flexion deficits (8 patients), patellar fractures (6 patients), and patellofemoral arthrosis/pain (5 patients). Eighteen of 38 (47%) complications were secondary to technical factors and were considered preventable. Female sex and bilateral MPFL reconstructions were risk factors associated with postoperative complications. Conclusion: Complications occurred in 16.2% of MPFL reconstruction surgeries for patellar instability in young patients, with almost half resulting from technical problems. Patients should be counseled preoperatively on the risk of potential complications.

Background: Femoral trochlear dysplasia is a known risk factor for patellar instability. The growth pattern of the normal trochlea is known, but there have been no studies investigating the growth and development of the dysplastic trochlea. The purpose of this study was to assess the growth pattern of trochlear dysplasia in adolescents. Methods: In a retrospective analysis, magnetic resonance images of adolescents with patellar instability and trochlear dysplasia were evaluated. These images were measured for lateral and medial condylar height, trochlear height, cartilaginous and bony trochlear bump, and cartilaginous and bony sulcus angle. The type of trochlear dysplasia was classified as per Dejour classification. These measurements were plotted against age, and their growth patterns were evaluated using statistical methods. Results: Of 235 knees with patellar instability, trochlear dysplasia was present in 175 knees (74% knees) and these were further analyzed. With increasing age, the mean lateral and medial condylar heights and mean trochlear height showed statistically significant increase (P<0.01). Cartilaginous trochlear bump (slope=0.15, P=0.013) and bony trochlear bump (slope=0.22, P<0.01) increased with age, with some reaching the pathologic value by age of 15.1 years. After age 11 years, there were no significant changes for cartilaginous and bony sulcus angles (cartilage: slope=0.03, P=0.96; bony: slope=−0.90, P=0.11). The mean cartilaginous sulcus angle was significantly greater than the mean bony sulcus angle (P<0.01). All Dejour types of trochlear dysplasia were present across all age groups. Conclusions: All linear measurements of trochlear dysplasia (condylar height, trochlear height, trochlear bump) increased with age. However, the shape of trochlear dysplasia, as reflected by sulcus angle and Dejour classification, did not change with increasing age. The shape of trochlear dysplasia is most likely a genetic predisposition and does not necessarily change during skeletal growth. Level of Evidence: Level II—diagnostic, cross-sectional.

Background Operating room (OR) human traffic has been implicated as a cause of surgical site infection. We first observed the normal human traffic pattern in our Pediatric Orthopedic ORs, and then examined the effect of surveillance on that traffic pattern. Methods This study consisted of 2 phases: phase I sought to observe the OR traffic pattern (number of door swings, maximum and minimum number of OR personnel, number of OR personnel at 30-minute intervals, or changes in nursing, anesthesia, or surgeon staff) during surgical cases without OR personnel being notified, and for phase II, the same traffic pattern was monitored with their knowledge. Results Two thousand four hundred forty-two minutes of surgical time were observed in phase I, and 1908 minutes were observed in phase II. There was no difference (P=0.06) in the time between door swings between phase I (1.39 min) and phase II (1.70 min), no difference (P=1.000) in the maximum number of people in the OR between phase I (11.5 people, range: 7-15 people) and phase II (11.5 people, range: 8-20 people), and no difference (P=1.000) in the minimum number of people in the OR between phase I (4.67 people, range: 4-6 people) and phase II (4.71 people, range: 3-6 people). There was a difference in the time between door swings (P=0.03) and maximum number of people in the OR (P=0.005) based on the length of the surgery (less or more than 120 min). There was no difference in the time between door swings (P=0.11), but there was a difference in the maximum number of people in the OR (P=0.002) based on type of surgery (spine vs. others). Conclusions There was no role of surveillance of human traffic in the OR. To achieve any change in the OR traffic pattern, monitoring alone may not be sufficient; other novel techniques or incentives may need to be considered.

Background: Nonoperative treatment after first-time patellar dislocation is the standard of care. There is evidence that certain patients may be at high risk for recurrent instability. The aim of this study was to develop a multivariable model to guide management of patients based on their individual risk of recurrent dislocation. Methods: A multivariable model was developed using 291 patients from 4 institutions to identify which patients were at higher risk for recurrent patellar dislocation within 2 years. This model was informed by a univariable logistic regression model developed to test factors based on the patient’s history, physical examination, and imaging. The discriminatory ability of the model to classify who will or will not have a recurrent dislocation was measured using the area under the receiver operating characteristic curve (AUC). Results: Age, a history of a contralateral patellar dislocation, skeletal immaturity, lateral patellar tilt, tibial tubercle-trochlear groove (TT-TG) distance, Insall-Salvati ratio, and trochlear dysplasia were the most important factors for recurrent patellar dislocation. Sex, mechanism of injury, Caton-Deschamps ratio, sulcus angle, inclination angle, and facet ratio were not factors for recurrent dislocation. The overall AUC for the multivariable model was 71% (95% confidence interval [CI]: 64.7% to 76.6%). Conclusions: Optimizing the management of lateral patellar dislocation will improve short-term disability from the dislocation and reduce the long-term risk of patellofemoral arthritis from repeated chondral injury. This multivariable model can identify patients who are at high risk for recurrent dislocation and would be good candidates for early operative treatment. Further validation of this model in a prospective cohort of patients will inform whether it can be used to determine the optimal treatment plan for patients presenting with an initial patellar dislocation. Until validation of the model is done with new patients, it should not be used in clinical practice. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.