Total knee arthroplasty is used as the treatment plan for patients with end-stage osteoarthrosis associated with severely affected function. Although TKA has been used for many years, some patients have reported overall dissatisfaction regarding the outcome. This may be due to the complexity of the joint design. In recent years, the concept of single-radius knee prosthetics is gaining more popularity as many studies have discussed biomechanical and clinical benefits of such design compared to traditionally used multi-radius implants. In this study, we report the outcome of 78 patients who were treated by TKA utilizing a relatively new single-radius implant, Unity. Results showed that all subjects reported good outcomes as expressed by significant improvement in their Knee Injury and Osteoarthritis Outcome Scores at 1-year post-operative. The symptom, pain, and ADL subscores demonstrated significant improvement in patients with scores twice the pre-operative value, while the average improvement in sport and quality of life subscores showed even greater improvement with scores three times the pre-operative value.

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Surface electromyography (EMG) is a valuable tool in clinical diagnostics and research related to human neuromotor control. Non-linear analysis of EMG data can help with detection of subtle changes of control due to changes of external or internal constraints during motor tasks. However, non-linear analysis is complex and results may be difficult to interpret, particularly in clinical environments. We developed a non-linear analysis tool (SYNERGOS) that evaluates multiple muscle activation (MMA) features and provides a single value for description of activation characteristics. To investigate the responsiveness of SYNERGOS to kinetic changes during cyclic movements, 13 healthy young adults performed squat movements under different loading conditions (100%-120% of body weight). We processed EMG data to generate SYNERGOS indices and used two-way repeated measures ANOVA to determine changes of MMA in response to loading conditions during movement. SYNERGOS values were significantly different for each loading condition. We concluded that the algorithm is sensitive to kinetic changes during cyclic movements, which may have implications for applications in a variety of experimental and diagnostic settings.

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Femoral neck-preserving short- (NPS) stem implants for total hip arthroplasty (THA) bear several advantages over longer-stem implants, such as native hip structure preservation and improved physiological loading. However, there still is a gap of knowledge regarding the potential benefits of a short-stem design over conventional neck-sacrificing stems in regards to patient-reported outcomes (PROs). The authors investigated the differences in PROs between a neck-sacrificing stem design and NPS stem design arthroplasty. They hypothesized that PROs of NPS stem THA would be higher in the medium-term in comparison to the neck-sacrificing implant system. Neck-sacrificing implant patients (n = 90, age 57 ± 7.9 years) and a matched (body mass index [BMI], age) cohort group of NPS implant patients (n = 105, age 55.2 ± 9.9 years) reported both preoperative and postoperative hip disability and osteoarthritis outcome scores (HOOS). Average follow-up was 413 ± 207 days (neck sacrificing implant) and 454 ± 226 days (NPS implant). The authors applied multivariate analysis of variance (MANOVA) and Mann–Whitney tests for statistical analyses. Significance levels were Holm–Bonferroni adjusted for multiple comparisons. HOOS Subscores increased significantly after surgery independent of implant type (p < 0.001). There was a significant time by surgery interaction (p = 0.02). Follow-up HOOS subscores were significantly higher in the NPS implant group: symptoms (p < 0.001), pain (p < 0.001), activities of daily living (ADL; p = 0.011), sports and recreation (p = 0.011), and quality of life (QOL; p = 0.007). While long-term studies are required for further investigation, evidence from the current study suggests that NPS implants may provide a significant benefit to primary THA patients, which could be due to physiological loading advantages or retention of bone tissue.