Posterior condylar offset changes and its effect on clinical outcomes after posterior-substituting, fixed-bearing total knee arthroplasty: anterior versus posterior referencing.

BACKGROUND: We sought to determine whether there was a difference in the posterior condylar offset (PCO), posterior condylar offset ratio (PCOR) and clinical outcomes following total knee arthroplasty (TKA) with anterior referencing (AR) or posterior referencing (PR) systems. We also assessed whether the PCO and PCOR changes, as well as patient factors were related to range of motion (ROM) in each referencing system. METHODS: This retrospective study included 130 consecutive patients (184 knees) with osteoarthritis who underwent primary posterior cruciate ligament (PCL)-substituting fixed-bearing TKA. The difference between preoperative and postoperative PCO and PCOR values were calculated. Clinical outcomes including ROM and Western Ontario and McMaster University (WOMAC) scores were evaluated. Furthermore, multiple linear regression analysis was performed to determine the factors related to postoperative ROM in each referencing system. RESULTS: The postoperative PCO was greater in the AR group (28.4 mm) than in the PR group (27.4 mm), whereas the PCO was more consistently preserved in the PR group. The mean postoperative ROM after TKA was greater in the AR group (129°) than in the PR group (122°), whereas improvement in WOMAC score did not differ between the two groups. Preoperative ROM was the only factor related to postoperative ROM in both groups. CONCLUSIONS: There was no difference in postoperative PCO in AR and PR group and the PCO was not associated with postoperative ROM. PCO was more consistently preserved after surgery in the PR group. The postoperative PCO and PCOR changes did not affect the postoperative ROM. Furthermore, similar clinical outcomes were achieved in the AR and PR groups. TRIAL REGISTRATION: Retrospectively registered (Trial registration number: 06-2010-110).

Quantitative evaluation of gait features after total knee arthroplasty: Comparison with age and sex-matched controls.

BACKGROUND: Gait function after total knee arthroplasty (TKA) is suboptimal. However, quantified analysis with comparing a control group is lacking. RESEARCH QUESTION: The aims of this study were 1) to compare the gait before and after TKA and 2) to compare postoperative gait to that of an age-sex matched control group. METHODS: This study consisted of 46 female and 38 male patients with end-stage knee osteoarthritis who underwent bilateral TKA, and 84 age- and sex-matched controls without knee pain and osteoarthritis. Seven gait parameters, including lower extremity alignment, knee adduction moment (KAM), knee flexion angle, external knee flexion moment, hip adduction angle, external hip adduction moment, and the varus-valgus arc during the stance phase, were collected using a commercial opto-electric gait analysis system. Principal component analysis was used for data processing and the standardized mean differences (SMDs) of the principal component scores were compared. RESULTS: The most significant gait change after TKA was the alignment (SMD 1.62, p < 0.001). The average stance phase alignment changed from varus 7.3° to valgus 0.5°. The second significant change was a decrease of the KAM (SMD 1.08, p < 0.001). These two features were closely correlated (r = 0.644, p < 0.001). The gait feature that differed most from the controls was the varus-valgus arc during the stance phase (SMD 1.68, p < 0.001), which was constrained by 31% after TKA (p < 0.001) and was only 37% compared to the controls (p < 0.001). SIGNIFICANCE: Improvement in gait after TKA was obtained through alignment correction. However, TKA significantly constrained coronal knee motion. TKA improved gait suboptimally; the gait was significantly different from that of controls.

A Transpatellar Approach to Treat Distal Femoral Type C3 Fractures Combined with Patellar Fractures.

We report our surgical method used to treat type C distal femur fractures accompanied by patella fractures whereby we approach the articular surface of the femur through the already-fractured patella. We treated 10 patients with type C3 distal femur and patella fractures between May 2013 and April 2015. Because the patella was fractured in all cases, we could approach the articular surface of the distal femur through the transverse gap between the retracted patellar fracture fragments, "transpatellar approach." Any surgical complications were recorded. Knee function was evaluated using the Böstman system. The average age of the 10 patients (8 males) was 42.9 years (range, 22.0-58.0 years). All distal femur fractures were type C3, combined with patella fractures. Bony union of the distal femur and patella was achieved in all but one patient, who required an additional bone graft (without any change in the implant). Overall, three patients (30%) reported excellent results and seven (70%) reported good results, based on the Böstman system. A midline anterior approach through a patella fracture adequately exposes the entire joint surface of the distal femur, except the posterior surface. This approach is useful when treating a type C distal femur fracture accompanied by a patella fracture. The level of evidence is IV.

One-Barrel Microsurgical Fibula Flap for Reconstruction of Large Defects of the Femur.

Various methods for reconstructing large femur bone defects after tumor resection have been introduced. In this study, we reviewed the clinical outcomes of using a 1-barrel free vascularized fibular graft (FVFG) protected by a lateral locking plate for large femoral defects not involving the knee joint.Between August 2007 and August 2013, we treated 7 patients with large femoral bone defects after tumor resection. The mean age of the patients was 19 years (range, 12-36 years), and 3 were women. All defects were free of infection before the procedure. Femoral bone defects were reconstructed using a 1-barrel FVFG protected by a lateral locking plate. The mean bone defect size was 10.5 cm (range, 6-16 cm). We reviewed clinical outcomes at the last follow-up.All patients survived beyond the last follow-up; the mean follow-up period was 54 months (range, 26-100 months). Two patients sustained stress fractures of the FVFG, but the lateral locking plate protected the fractured graft until in situ bone healing obtained. Mean time to bone union of both host-graft junctions was 24 months (range, 18-31 months). The mean Musculoskeletal Tumor Society score (%) was 85.8% (range, 80-95%).A 1-barrel FVFG protected by a lateral locking plate maintained a stable graft-host bone construct, successfully leading to bone healing, even in cases of stress fractures of the graft, and appears to be a good option for large femur bone defects.