Background In comparison to static spacers, articulating spacers have been shown to result in a similar infection eradication rate in two-stage revision of periprosthetic knee infections. However, the optimal construct for articulating spacers has not been identified yet. The aim of this study was to present a preliminary result of treatment for periprosthetic knee infection using a novel computer-aided design (CAD)-articulating spacer. Methods We retrospectively reviewed 32 consecutive cases of chronic periprosthetic knee infection occurring from January 2015 to December 2015. In these cases, we used an antibiotic-loaded, optimized CAD-articulating spacer based on the retrieved knee prosthesis. Evaluation included infection eradication rate, the Hospital of Special Surgery (HSS) knee score, range of motion (ROM), and spacer-related mechanical complications. All cases were regularly followed-up for 2 years minimum. Results Twenty-eight of 32 patients (87.5%) had infection eradication; 18 patients (56.3%) received reimplantation successfully. The mean interval between spacer insertion and reimplantation was 8.8 months (range 4.0–12.5 months). The mean HSS knee score and ROM significantly increased during each interval ( p < 0.0001 for both). The mean HSS knee scores were 31.2 (range 20–48) at initial visit, 65.4 (range 60–78.8) at 1 month after spacer insertion, and 84.2 (range 78–90) at 3 months after reimplantation ( p < 0.0001). The mean ROM were 72.0° (range 15–100°), 85.6° (range 35–110°), and 102.0° (range 80–122°), respectively ( p = 0.002). Two (6.3%) spacer-related mechanical complications occurred. Conclusions The CAD-articulating spacer in two-staged revision of periprosthetic knee infection significantly controlled infection, improved clinical outcomes, increased ROM, and decreased mechanical complications in the preliminary study. Further larger clinical studies are needed to confirm the findings presented here.

BackgroundRetractor placement is a leading cause of intraoperative nerve injury during total hip replacement (THR) surgery. The sciatic nerve, femoral nerve, and superior gluteal nerve are most commonly affected. This study aimed to identify the distances from bony landmarks in the hip to the adjacent nerves on magnetic resonance imaging (MRI) and the associations between anatomical factors and these distances that would guide the placement of retractors during THR surgery, in order to minimize the risk of nerve injury.MethodsWe reviewed hip MRIs of 263 adults and recorded the distances from (1) the anterior acetabular rim to the femoral nerve; (2) the superior acetabular rim to the superior gluteal nerve; (3) the posterior acetabular rim to the sciatic nerve; and (4) the greater trochanter to the sciatic nerve. The effects of anatomical factors (i.e., gender, age, body height, body mass index (BMI), pelvic width, and acetabular version and morphology) on these distances were analyzed.ResultsDistances from bony landmarks to adjacent nerves (in cm) were 2.06 ± 0.44, 2.23 ± 0.28, 1.94 ± 0.81, and 4.83 ± 0.26 for the anterior acetabular rim, superior acetabular rim, posterior acetabular rim, and greater trochanter, respectively, and were shorter in women than in men (P < 0.001). Multivariate analysis identified body height as the most influential factor (P < 0.001). Linear regression demonstrated a strong positive linear correlation between body height and these distances (Pearson’s r = 0.808, 0.823, 0.818, and 0.792, respectively (P < 0.001)).ConclusionsThe distances from bony landmarks to adjacent nerves provide useful information for placing retractors without causing nerve injury during THR surgery. Shorter patients will have shorter distances from bony landmarks to adjacent nerves, prompting more careful placement of retractors.

ObjectiveThe purpose of this study is to compare glenopolar angle (GPA) and the functional outcomes of fixation of both the clavicle and the scapular neck, fixation of the clavicle alone, and conservative treatment for floating-shoulder injuries.MethodsA prospective stratified randomized study was performed in 39 adult patients who suffered floating-shoulder injuries and underwent fixation of both the clavicle and the scapular neck (group A), or fixation of the clavicle alone (group B), or conservative treatment (group C) between January 2005 and September 2011. The GPA, Disabilities of the Arm, Shoulder and Hand (DASH) score, and Constant-Murley Shoulder Outcome (Constant) score were compared between the three groups.ResultsAll 39 patients were followed up for more than 2 years. GPA after bony consolidation was significantly better in group A than in groups B and C (p = 0.015). Functional outcomes measured by DASH and Constant scores were significantly better in group A at final follow-up (p = 0.008 and 0.002, respectively). Both DASH and Constant scores were highly correlated with GPA after consolidation (p < 0.001, respectively). The receiver operating characteristic (ROC) analysis showed that of the two randomly selected DASH scores, the smaller DASH score would have a larger GPA than the larger DASH score. Similarly, the larger Constant score would have a larger GPA than the smaller Constant score.ConclusionsFixation of both the clavicle and the scapular neck may correct GPA and improve functional outcomes for the treatment of floating-shoulder injuries. GPA after fracture consolidation is a useful prognostic indicator of a satisfactory clinical outcome as defined by either DASH score or Constant score.