Can a Total Knee System Providing 1 mm Increment of Polyethylene Insert Thickness Offer a Clinical Benefit?

Background and Objectives: The purpose of this study was to compare clinical outcomes and polyethylene (PE) insert thickness between total knee arthroplasty (TKA) systems providing 1 mm and 2 mm increments. Materials and Methods: In this randomized controlled trial, 50 patients (100 knees) undergoing same-day or staggered bilateral TKA were randomized to receive a TKA system providing 1 mm increments in one knee (1 mm group) and a TKA system providing 2 mm increments in the other knee (2 mm group). At 2 years postoperatively, Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Forgotten Joint Score (FJS), range of motion (ROM), and insert thicknesses were compared between the groups. Results: A total of 47 patients (94 knees) participated in follow-up analysis. In each group, patient-reported outcomes improved significantly after TKA (all, p < 0.05). There were no significant differences in patient-reported outcomes. The mean ROM was not significantly different between groups at preoperative and 2-year points. The rate of postoperative flexion contracture ≥ 5° was 2.1% and 4.3%, and the rate of postoperative recurvatum ≥ 5° was 4.3% and 2.1% in the 1 mm group and 2 mm, respectively (all, p = 1.000). Mean insert thickness was significantly thinner in the 1 mm group than the 2 mm group (p = 0.001). The usage rate of a thick insert (≥14 mm) was 12.7% and 38.3% in the 1 mm group and 2 mm group (p = 0.005). Conclusions: The use of a TKA system providing 1 mm PE insert thickness increments offered no clinical benefit in terms of patient reported outcomes over systems with 2 mm increments at 2 years of follow-up. However, the TKA system with 1 mm increments showed significantly thinner PE insert usage. As a theoretical advantage of 1 mm increments has yet to be proven, the mid- to long-term effects of thinner PE insert usage must be determined.

Comparison of in-situ release and submuscular anterior transposition of ulnar nerve for refractory cubital tunnel syndrome, previously treated with subfascial anterior transfer-A retrospective study of 24 cases.

BACKGROUND: Although cubital tunnel syndrome is the second most common type of compressive neuropathy in the upper extremities, the indication and optimal surgical method for recurrent or refractory cubital tunnel syndrome remains controversial. This study evaluates the functional outcomes of revision surgery for cubital tunnel syndrome. MATERIAL & METHODS: This study was a retrospective observational multicenter single-institution study including 660 patients who underwent surgery for cubital tunnel syndrome from 2010 to 2019. Among the 660 patients, 42(6.4%) received revision surgery due to remaining or recurrent symptoms confirmed with electromyography(EMG). After excluding those with concurrent elbow fracture, dislocation, osteoarthritis and wound infection, a total of 24 patients were included in the study. The patients were evaluated of disease severity, revision surgical method, time interval to recurrence, underlying diseases and postoperative functional outcomes. RESULTS: All patients received ulnar nerve subfascial anterior transposition for the initial cubital tunnel syndrome surgery. Among the 24 patients (3.7%) who received revision surgery, nine received in situ neurolysis, 12 received submuscular transposition, and three received subcutaneous transfer. 21 patients (88%) reported improved mean VAS score of 4.3, while three patients complained of remaining symptoms that did not improve even after revision surgery. The patients with remaining symptoms all had underlying diabetes mellitus and were treated with subcutaneous transfer. The difference of surgical outcomes between the in situ neurolysis group and the nerve transfer groups were non-significant (p = 0.23). The most common cause of recurrent or persistent symptoms was adhesion and fibrosis at sling area. The mean follow up period before revision surgery was 26.3 months and postoperative follow up period after revision surgery was 8.5 months. CONCLUSION: The outcomes of this study imply that in-situ neurolysis may be as effective as anterior submuscular transfer of ulnar nerve for refractory cubital tunnel syndrome after anterior subfascial transfer.