Valgus high tibial osteotomy (HTO) results in changes in the frontal as well as sagittal planes. Our hypothesis suggests that patellar height increases and posterior tibial inclination decreases after closed wedge (cw) HTO, whereas patellar height decreases and tibial slope increases after open wedge (ow) HTO.

Lateral radiographs of 100 knees were assessed for patellar height (PH) using Insall-Salvati (ISI), Caton-De Champ (CDI) and Blackburne-Peel indices (BPI) as well as posterior tibial slope. Measurements were done before HTO (50 cw and 50 ow), direct postoperatively and before hardware removal.

In the cw-group all three PH indices increased direct postoperatively and at removal of the hardware with changes in CDI and BPI being significant (P < 0.05). In the ow-group all three indices showed a significant patellar height decrease direct postoperatively and at hardware removal. There were no significant changes between the two follow-up measurements (P > 0.05). Posterior tibial slope showed a significant decrease of 3.1 ± 3.4° after closed wedge HTO and a significant increase of 2.1 ± 3.6° after ow HTO direct postoperatively. In cw-HTO the correlations between frontal plane correction and PH changes were moderate (CDI: r = 0.57; BPI: r = 0.64). In ow-HTO these correlations were weak (CDI: r = 0.44; BPI: r = 0.46). According to ISI there was no correlation (cw: r = 0.11; ow: r =0.16). There was no correlation between PH changes according to CDI and slope changes.

The incidence of patella infera increases after open wedge HTO, whereas the incidence of patella alta increases after closed wedge HTO. We recommend considering the PH and tibial slope before planning for HTO or TKR after HTO, also performing cw-HTO or ow-HTO with the tuberosity left at the proximal tibia in cases of patellofemoral complaint or patella infera.

Introduction: Scapular manipulation is one of the most successful techniques for reducing anterior shoulder dislocations. However, as there is evidence in the literature that elbow flexion can avoid tendon interposition and muscular compression forces on the glenohumeral joint are at a minimum in the overhead position, we created a modification of the original technique with the principle of scapular manipulation in overhead position and traction on the upper arm with the elbow flexed. The aim of this study was to assess the effectiveness of this new method.

Methods: 62 patients with acute anterior shoulder dislocation who were treated with this new method were evaluated prospectively with regard to primary success rate and reduction time as main outcome parameters. Results were compared to the published data on the original method. Statistics was conducted using the chi-square test and the ANOVA post hoc test with Bonferroni-Dunn-transformation.

Results: 59 of the 62 dislocations (61% first time dislocations, 21% with associated fractures) were reduced successfully by use of the new method by 21 different physicians indicating a primary success rate of 95.2%. The mean reduction time was 3.13 minutes. Primary success rates of the original method reported in 5 studies range from 78.4 to 96.0% (mean 87.1%). In 2 out of 5 single test and global level comparisons our new modification revealed a statistically significant better primary success rate compared to the original method (p< 0.05). There were no iatrogenic complications in our study, and the method was easy to perform even without any experience in reducing shoulder dislocations.

Conclusion: Modification by overhead position and elbow flexion can even improve the high primary success rate of the original scapular manipulation technique. Therefore, the method is strongly recommended as a first choice technique for reducing anterior shoulder dislocations.

Objective: Ex vivo studies have suggested that cartilage contact areas and pressure are of high clinical relevance in the ethiology of osteoarthritis in patients with patellar subluxation. The aims of this study were therefore to validate in vivo measurements of contact areas with 3D open magnetic resonance imaging (MRI), and to study knee joint contact areas in patients with patellar subluxation at different angles of knee flexion in comparison with healthy subjects.

Methods: 3D-MR image data sets of 12 healthy volunteers and 8 patients with patellar subluxation were acquired using a standard clinical (1.5T) and an open (0.2T) MRI scanner. We compared femoro-patellar and femoro-tibial contact areas obtained with two different sequences from open MRI [dual-echo-steady-state (DESS) and fast-low-angle-shot (FLASH) sequences] with those derived from standard clinical 1.5 T MRI. We then analyzed differences in joint contact areas between healthy subjects and patients with patellar subluxation at 0, 30 and 90 of knee flexion using open MRI.

Results: The correlation of the size of contact areas from open MRI with standard clinical MRI data ranged from r = 0.52 to 0.92. Open-MRI DESS displayed a smaller overestimation of joint contact areas (+21 % in the femoro-patellar, +12% in the medial femoro-tibial, and +19% in the lateral femoro-tibial compartment) than FLASH (+40%, +37%, +30%, respectively). The femoro-patellar contact areas in patients were significantly reduced in comparison with healthy subjects (− 47% at 0, − 56% at 30, and − 42% at 90 of flexion; all p < 0.01), whereas no significant difference was observed in femoro-tibial contact areas.

Conclusions: Open MRI allows one to quantify joint contact areas of the knee with reasonable accuracy, if an adequate pulse sequences is applied. The technique permits one to clearly identify differences between patients with patellar subluxation and healthy subjects at different flexion angles, demonstrating a significant reduction and lateralization of contact areas in patients. In the future application of this in vivo technique is of particular interest for monitoring the efficacy of different types of surgical and conservative treatment options for patellar subluxation.