Clinical outcomes of various types of revision surgeries after unicompartmental knee arthroplasty failure.

PURPOSE: The advantages of unicompartmental knee arthroplasty (UKA) have led to the procedure being increasingly performed worldwide. However, revision surgery is required after UKA failure. According to the literature review, the choice of implant in revision surgery remains a debatable concern. This study analyzed the clinical results of different types of prostheses used in treating failed UKA. MATERIALS AND METHODS: This is a retrospective review of 33 failed medial UKAs between 2006 and 2017. Demographic data, failure reason, types of revision prostheses, and the severity of bone defects were analyzed. The patients were classified into three groups: primary prosthesis, primary prosthesis with a tibial stem, and revision prosthesis. The implant survival rate and medical cost of the procedures were compared. RESULTS: A total of 17 primary prostheses, 7 primary prostheses with tibial stems, and 9 revision prostheses were used. After a mean follow-up of 30.8 months, the survival outcomes of the three groups were 88.2%, 100%, and 88.9%, respectively (P = 0.640). The common bone defect in tibia site is Anderson Orthopedic Research Institute [AORI] grade 1 and 2a (16 versus 17). In patients with tibial bone defects AORI grade 2a, the failure rates of primary prostheses and primary prostheses with tibial stems were 25% and 0%, respectively. CONCLUSIONS: The most common cause for UKA failure was aseptic loosening. The adoption of a standardized surgical technique makes it easier to perform revision surgeries. Primary prostheses with tibial stems provided higher stability, leading to a lower failure rate due to less risk of aseptic loosening in patients with tibial AORI grade 2a. In our experience, we advise surgeons may try using primary prostheses in patients with tibial AORI grade 1 and primary prostheses with tibial stems in patients with tibial AORI grade 2a.

Association Between Obstructive Sleep Apnea and Diabetic Macular Edema in Patients with Type 2 Diabetes.

PURPOSE: To evaluate the relationship between obstructive sleep apnea (OSA) and diabetic macular edema (DME) and the effect of OSA on refractory DME in patients with type 2 diabetes (T2DM). DESIGN: Retrospective clinical cohort study. METHODS: A population-based study was conducted at Chang Gung Memorial Hospital from March 1, 2009, to March 1, 2020. Among 14,152 patients who had undergone polysomnography (PSG) and whose data were registered on the sleep center's PSG database, 121 patients (242 eyes) with T2DM were enrolled according to the International Classification of Diseases, Ninth Revision (ICD-9) code 3620 for diabetic retinopathy (DR). Patients with a secondary cause of macular edema and those lacking medical records were excluded. All patients with T2DM enrolled in our study received both optical coherence tomography (OCT) and PSG. The prevalence of severe (apnea-hypopnea index [AHI] ≥30) and nonsevere (AHI <30) OSA was compared between patients with and without DME and refractory DME. RESULTS: In total, 102 eyes (54 patients) were divided into groups of 40 eyes with DME or 62 eyes without DME. Severe OSA (odds ratio, 7.36; 95% confidence interval [CI]: 1.32-40.96; P = .023) was significantly associated with DME. Refractory DME was significantly more frequent in patients with severe OSA (27%) than in those with nonsevere OSA (0%; P = .009). Cox proportional hazards regression analysis revealed that OSA (hazard ratio, 2.97; CI, 1.08-8.16; P = .034) independently increased the DME risk after adjustment for age, sex, glycohemoglobin level, hypertension, and hypercholesterolemia. CONCLUSIONS: Severe OSA is a risk factor for DME and is associated with having refractory DME.