Intraoperative adjustment of alignment under valgus stress reduces outliers in patients undergoing medial opening-wedge high tibial osteotomy.

INTRODUCTION: A considerable percentage of outliers with under- or over-correction continue to be reported despite precise preoperative planning and cautious intraoperative correction of lower limb alignment in medial opening-wedge high tibial osteotomy (MOWHTO). The purpose of this study was to determine whether our novel technique for the intraoperative adjustment of alignment under valgus stress reduces the number of outliers in patients undergoing MOWHTO compared to the conventional technique, which corrects alignment according to the cable method only. MATERIALS AND METHODS: One hundred seventeen consecutive knees were enrolled in this case-control study. The first 52 knees (51 patients) were corrected in accordance with preoperative plans using the Dugdale method with modification with an intraoperative cable (group 1). In the other 65 knees (60 patients), the angle was corrected using the Dugdale method and limb alignment was adjusted using the intraoperative cable technique by applying valgus stress to the knee joint (group 2). The postoperative weight bearing line ratios and mechanical axis of the lower limb were compared at postoperative one year. Each knee was evaluated according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score preoperatively and at postoperative one year. RESULTS: A significant reduction in the number of outliers was seen in group 2 compared to group 1 (group 1 = 48.1%, group 2 = 9.2%, p < 0.001). Nineteen of 52 knees (36.5%) were under-corrected in group 1, whereas 6 of 65 knees (9.2%) were under-corrected in group 2 (p < 0.001). Six of 52 knees (11.6%) were over-corrected in group 1, whereas 0 of 65 knees (0.0%) were over-corrected in group 2 (p = 0.005). At one -year after operation, group 2 showed significantly lower WOMAC score than group 1 (p = 0.014). CONCLUSIONS: Intraoperative adjustment of alignment under valgus stress significantly reduced the number of outliers compared to a technique that corrected alignment using the cable method in patients undergoing MOWHTO. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis.

BACKGROUND: Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD) after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters. MATERIALS AND METHODS: 98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI), medical comorbidities and bone mineral density (BMD). The radiological parameters taken into consideration were Cobb's angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI) and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level) and posterolateral lumbar interbody fusion (PLIF). Clinical outcomes were assessed with the Visual Analogue Score (VAS) and Oswestry Disability Index (ODI). RESULTS: ASD was present in 44 (44.9%) patients at an average period of 48.0 months (range 6-98 months). Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI) and age at operation (P = 0.0001, 0.0364). There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531). CONCLUSIONS: Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI) were at a higher risk of developing ASD.