Application of a true lateral virtual radiograph from 3D-CT to identify the femoral reference point of the medial patellofemoral ligament.

PURPOSE: The purpose of this study is two-fold: (1) to describe the femoral reference point of the medial patellofemoral ligament (MPFL) on a virtual true lateral radiograph reconstructed from a three-dimensional computed tomography (3D-CT) image and (2) to compare this point with that of patients without patellofemoral instability and with Schöttle's point. METHODS: A total of 26 consecutive patients (29 affected knees) with recurrent patellar dislocation (RPD), who underwent MPFL reconstruction were included in this study (4 males; 22 females; mean age, 24.0 years old). Using a true lateral 3DCT image, the MPFL femoral insertion was identified and marked with a 2-mm circle, and this image was reconstructed as a virtual true lateral radiograph. Following Schöttle's method, the point of intersection was described by their anterior-posterior and proximal-distal positions. As a control population, 29 age- and gender-matched patients with anterior cruciate ligament (ACL) injuries were also analysed. RESULTS: The points in RPD patients were located significantly posterior (-2.5 ± 2.3 mm, p < 0.01) to the line representing an extension of the posterior cortex of the femur and distal (- 6.9 ± 2.4 mm, p < 0.01) to the posterior origin of the medial femoral condyle compared with those in the control population. The mean reference point of RPD patients was located in a 3.8-mm posterior and 4.4-mm distal position compared with Schöttle's point. CONCLUSIONS: An anatomical and radiographic femoral reference point of the MPFL on a true lateral virtual radiograph was described with our method. In patients with RPD, this reference point was identified to be more posterior and distal to Schöttle's point. More anatomical and individualized MPFL reconstruction will be secured using our method. LEVEL OF EVIDENCE: Level IV.

Autologous mesenchymal stem cell application for cartilage defect in recurrent patellar dislocation: A case report.

INTRODUCTION: Recurrent patellar dislocation can lead to articular cartilage injury. We report a 21-year old male with left patella instability and articular cartilage defect. PRESENTATION OF CASE: A 21-year-old male presented with left patellar instability and pain. Knee range of motion (ROM) was limited when patella was dislocated (0-20°). The J-sign positive, patellar apprehension test was positive, with medial patella elasticity/patellar glide >2 quadrants. The Q angle, in the 90° flexed knee position was still normal. The plain radiograph imaging showed no abnormality. Insall-Salvati index was 1.12. The patient was diagnosed with recurrent patellar dislocation and cartilage lesion of the left knee, and was treated with combining Fulkerson osteotomy with the lateral retinacular release and percutaneous medial plication, followed by microfracture procedure and MSCs implantation. DISCUSSION: Recurrent patellar dislocation is uncommon problem while cartilage lesions following recurrent patellar dislocations are quite common, but still no consensus on the management. CONCLUSION: Combination of Fulkerson osteotomy with the lateral retinacular release and percutaneous medial plication was effective in treating chronic patellar instability. The microfracture procedure and MSCs implantation was safe and could improve the cartilage regeneration in patients with articular cartilage defect due to recurrent patellar dislocation.

Total hip replacement: A meta-analysis to evaluate survival of cemented, cementless and hybrid implants.

AIM: To determine whether cemented, cementless, or hybrid implant was superior to the other in terms of survival rate. METHODS: Systematic searches across MEDLINE, CINAHL, and Cochrane that compared cemented, cementless and hybrid total hip replacement (THR) were performed. Two independent reviewers evaluated the risk ratios of revision due to any cause, aseptic loosening, infection, and dislocation rate of each implants with a pre-determined form. The risk ratios were pooled separately for clinical trials, cohorts and registers before pooled altogether using fixed-effect model. Meta-regressions were performed to identify the source of heterogeneity. Funnel plots were analyzed. RESULTS: Twenty-seven studies comprising 5 clinical trials, 9 cohorts, and 13 registers fulfilled the research criteria and analyzed. Compared to cementless THR, cemented THR have pooled RR of 0.47 (95%CI: 0.45-0.48), 0.9 (0.84-0.95), 1.29 (1.06-1.57) and 0.69 (0.6-0.79) for revision due to any reason, revision due to aseptic loosening, revision due to infection, and dislocation respectively. Compared to hybrid THR, the pooled RRs of cemented THR were 0.82 (0.76-0.89), 2.65 (1.14-6.17), 0.98 (0.7-1.38), and 0.67 (0.57-0.79) respectively. Compared to hybrid THR, cementless THR had RRs of 0.7 (0.65-0.75), 0.85 (0.49-1.5), 1.47 (0.93-2.34) and 1.13 (0.98-1.3). CONCLUSION: Despite the limitations in this study, there was some tendency that cemented fixation was still superior than other types of fixation in terms of implant survival.