Tibial and femoral osteotomies in varus deformities - radiological and clinical outcome.

BACKGROUND: Varus deformities of the knee are frequently corrected by osteotomies, which should be performed at the level of origin. But in contrast to high tibial osteotomies (HTO), little data exists for distal femoral osteotomies (DFO). This study evaluates radiological and clinical outcomes after valgisation osteotomies in the proximal tibia and distal femur. METHODS: We used an observational cohort study design and prospectively performed preoperative long standing radiographs (LSR), lateral x-rays and clinical questionnaires (SF-36, Lysholm score, VAS). Postoperative LSR and lateral x-rays were obtained on average 18 months postoperative and postoperative clinical questionnaires at final visit (mean follow up 46 months). A subgroup analysis of the different surgical techniques (oHTO vs. cDFO) was performed, with regards to radiological and clinical outcomes. RESULTS: Finally 28 osteotomies with medial tibial opening (oHTO) or lateral femoral closing (cDFO) wedge osteotomies in 25 consecutive patients (mean age 40 years) were identified. There were 17 tibal and 11 femoral procedures. All osteotomies were performed at the origin of deformity, which was of different etiology. The average deviation of the final HKA compared to the preoperative planning was 2.4° ± 0.4°. Overall, there was a significant improvement in all clinical scores (SF-36: 61.8 to 79.4, p < 0.001; Lysholm-score: 72.7 to 90.4, p < 0.001; VAS: 3 to 1, p < 0.001). There was no significant correlation between surgical accuracy and outcome scores. CONCLUSION: Valgisation osteotomies lead to a significant improvement in all clinical scores with the demonstrated treatment protocol. An appreciable proportion of varus deformities are of femoral origin. Since cDFO provides comparable radiological and clinical results as oHTO, this is an important treatment option for varus deformities of femoral origin.

Intraoperative alignment correlates well with long standing radiographs - The X-ray grid method in complex knee surgery.

OBJECTIVE: While long standing radiographs (LSR) represent the gold standard for preoperative alignment assessment and planning of lower limb deformity corrections, there is no consensus about the intraoperative alignment assesments (IAC) due to various limitations of the common methods. The present study introduces a radiolucent X-ray grid with integrated radiopaque lines explicitly designed for fluoroscopic IAC and evaluates its reliability in comparsion to the LSR. METHODS: Patients with posttaumatic and congenital lower limb deformity surgery and preoperative LSR as well as fluoroscopic IAC utilizing the X-ray grid were retrospectively included to the study. The mechanical axis deviation (MAD) in percentage of the maximum tibial width from the medial to the lateral in comparison between the image pairs was set as primary outcome parameter. Multiple rater and measurements determined intra- and interobserver reliabilit of both imaging methods. In addition, the effects of age, gender, body mass index (BMI), etiology, joint line convergence angle (JLCA), and extent varus or valgus deformity were analysed. RESULTS: A total of 84 patients were finally included. The mean absolute difference of MAD between the two techniques was 7.2 ± 0.8%. MAD between the LSR and IAC correlated at a high level (R = 0.96, p <0.001). The agreement decreased with increasing extent of deformity (p <0.01) and with higher deviation of JLCA between LSR and IAC (p <0.01). Intra- and interobserver concordance correlation coefficient (CCC) for MAD measurements were 0.99 for both imaging techniques. CONCLUSION: Fluoroscopy combined with the X-ray grid method is a valid tool for intraoperative assessment of lower limb alignment in deformity correction surgery, and the correlation between LSR and IAC is better than in other similar techniques described in the literature. However, in case of severe coronal alignment deformity and highly divergent JLCA, the agreement between both imaging techniques decreases significantly.