Comparison of Fixation Techniques in Oblique and Biplanar Chevron Medial Malleolar Osteotomies; a Finite Element Analysis.

This study aimed to evaluate different fixation techniques and implants in oblique and biplanar chevron medial malleolar osteotomies using finite element analysis. Both oblique and biplanar chevron osteotomy models were created, and each osteotomy was fixed with 2 different screws (3.5 mm cortical screw and 4.0 mm malleolar screw) in 2 different configurations; (1) 2 perpendicular screws, and (2) an additional third transverse screw. Nine simulation scenarios were set up, including 8 osteotomy fixations and the intact ankle. A bodyweight of 810.44 N vertical loading was applied to simulate a single leg stand on a fixed ankle. Sliding, separation, frictional stress, contact pressures between the fragments were analyzed. Maximum sliding (58.347µm) was seen in oblique osteotomy fixed with 2 malleolar screws, and the minimum sliding (17.272 µm) was seen in chevron osteotomy fixed with 3 cortical screws. The maximum separation was seen in chevron osteotomy fixed with 2 malleolar screws, and the minimum separation was seen in oblique osteotomy fixed with 3 cortical screws. Maximum contact pressure and the frictional stress at the osteotomy plane were obtained in chevron osteotomy fixed with 3 cortical screws. The closest value to normal tibiotalar contact pressures was obtained in chevron osteotomy fixed with 3 cortical screws. This study revealed that cortical screws provided better stability compared to malleolar screws in each tested osteotomy and fixation configuration. The insertion of the third transverse screw decreased both sliding and separation. Biplanar chevron osteotomy fixed with 3 cortical screws was the most stable model.

Evaluation of prolidase activity and oxidative status in patients with knee osteoarthritis: relationships with radiographic severity and clinical parameters.

We investigated serum prolidase activity and oxidative/antioxidative status in patients with knee osteoarthritis (OA) and evaluated its relationships with radiographic severity and clinical parameters. The study population consisted of 137 patients with knee OA and 134 healthy volunteers. The severity of knee OA was classified according to the Kellgren-Lawrence criteria. Each patient was also evaluated clinically according to the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Serum prolidase activity was measured spectrophotometrically. Oxidative status was assessed by measuring serum lipid hydroperoxide (LOOH) and total oxidative status (TOS). Antioxidative status was assessed by measuring serum-free sulfhydryl groups (-SH = total thiol) and total antioxidant capacity (TAC). Oxidative stress index (OSI) was calculated. Serum prolidase activity was significantly lower in the knee OA group than in the control group (p < 0.001). The serum prolidase activities decreased with the severity of knee OA. Furthermore, serum LOOH, TOS, and OSI levels of the knee OA group were significantly higher than those of the controls (p < 0.001 for all), whereas TAC and -SH levels did not differ between the two groups (p > 0.05). In a multiple regression analysis, WOMAC score was independently associated with serum prolidase activity (ß = -0.340, p < 0.001). Decreased serum prolidase activity and elevated LOOH, TOS, and OSI levels may be associated with knee OA, and serum prolidase activity may be a useful adjunctive indicator of the progression of knee OA in follow-up.

The body composition of patients with knee osteoarthritis: relationship with clinical parameters and radiographic severity.

BACKGROUND AND AIMS: We investigated body composition in knee osteoarthritis (OA) patients and evaluated its relationship with clinical parameters and radiographic severity. METHODS: Sixty-four patients with knee OA (52 females and 12 males with a mean age of 57.7 ± 8.6 years) and thirty healthy volunteers (20 females and 10 males with a mean age of 56.3 ± 9.5 years) were evaluated. Controls were selected among similar to demographic and hematologic characteristics of patients. Body compositions were assessed via bioelectrical impedance analysis (BIA). Each patient was clinically evaluated by the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). In addition, radiographic severity was classified according to Kellgren-Lawrence's criteria. RESULTS: Phase angle, body capacitance, resistance, reactance, lean body mass, and intracellular water values of the patients with knee OA were found to be significantly lower than those of the controls (p < 0.05). Furthermore, fat mass and extracellular water levels were significantly higher in the patients compared to the controls (p < 0.05). Lean body mass was inversely correlated with WOMAC score (r = -0.716, p < 0.001), whereas fat mass was moderately correlated with WOMAC score (r = 0.281, p < 0.05) in bivariate analysis. However, with respect to the body composition, there was no significant difference between early grades and late grades in the knee OA with patients (p > 0.05). CONCLUSION: Body composition assessed using BIA might be associated with knee OA, and be a noninvasive tool for diagnosis of knee OA. However, body composition may not be predictive of the progression of knee OA.