A predictive score of high tibial osteotomy survivorship to help in surgical decision-making: the SKOOP score.

INTRODUCTION: The high tibial osteotomy (HTO) survival rate is strongly correlated with surgical indications and predictive factors. This study aims to assess HTO survival in the long term, to determine the main predictive factors of this survival, to propose a predictive score for HTO based on those factors. METHODS: This multicentric study included 481 HTO between 2004 and 2015. The inclusion criteria were all primary HTO in patients 70 years old and younger, without previous anterior cruciate ligament injury, and without the limitation of body mass index (BMI). The assessed data were preoperative clinical and radiological parameters, the surgical technique, the complications, the HKA (hip knee ankle angle) correction postoperatively, and the surgical revision at the last follow-up. RESULTS: The mean follow-up was 7.8 ± 2.9 years. The HTO survival was 93.1% at 5 years and 74.1% at 10 years. Age < 55, female sex, BMI < 25 kg/m2 and incomplete narrowing were preoperative factors that positively impacted HTO survival. A postoperative HKA angle greater than 180° was a positive factor for HTO survival. The SKOOP (Sfa Knee OsteOtomy Predictive) score, including age (threshold value of 55 years), BMI (threshold values of 25 and 35 kg/m2), and the presence or absence of complete joint line narrowing, have been described. If the scale was greater than 3, the survival probability was significantly lower (p < 0.001) than if the scale was less than 3. CONCLUSION: A predictive score including age, BMI, and the presence or absence of joint line narrowing can be a helpful in making decisions about HTO, particularly in borderline cases. LEVEL OF EVIDENCE: Retrospective cohort study.

Is patient-specific instrumentation more precise than conventional techniques and navigation in achieving planned correction in high tibial osteotomy?

INTRODUCTION: Preoperative planning in high tibial osteotomy (HTO) is a critical step for achieving the desired correction and a clinically satisfactory outcome. Conventional radiography, navigation assistance and patient-specific instrumentation (PSI) are the 3 means of planning, but no prospective studies have compared precision between the 3. The aims of the present study were: (1) to analyze and compare correction precision between the 3 planning approaches at 1 year's follow-up; (2) to compare results to those reported in the literature; and (3) to analyze factors influencing the achievement of planned correction. HYPOTHESIS: The study hypothesis was that PSI provides more precise and reproducible planned correction than conventional methods or navigation. MATERIAL AND METHOD: Between June 2017 and June 2018, a multicenter non-randomized prospective observational study was conducted in 11 centers. One hundred and twenty-six patients with Ahlbäck grade I, II or III idiopathic medial tibiofemoral osteoarthritis with stable knee were included and allocated to 3 preoperative planning groups: conventional (group 1), navigation (group 2) and PSI (group 3). Mean age at surgery was 51.2 years (range, 19-69 years; median, 53.2 years); 100 male, 26 female. Complete weight-bearing radiographic work-up was performed preoperatively and at 1 year's follow-up. The PSI group also underwent CT as part of guide production. Target angular correction and mechanical Hip-Knee-Ankle (HKA) axis were set preoperatively. The main endpoint was the difference between planned HKA and HKA at a minimum 12 months. RESULTS: Mean HKA difference was 1.1±3 in group 1, 2.1±2.6 in group 2 and 0.3±3.1 in group 3. Precision was better with PSI, but not significantly when comparing all 3 groups together. On pairwise intergroup comparison, there was a significant difference only between groups 2 and 3, in favor of PSI (P=0.011). DISCUSSION: None of the 3 techniques demonstrated superiority in achieving target correction at 1 year. The study hypothesis was thus not confirmed. All 3 techniques proved reliable and precise in HTO planning. LEVEL OF EVIDENCE: III, prospective non-randomized comparative study.

Seven-year results of a press-fit, hydroxyapatite-coated double mobility acetabular component in patients aged 65 years or older.

One hundred and thirty-four THA were done between 1998 and 2002 with AVANTAGE(®) Press-Fit double mobility cup. The mean age of patients was 74 ± 6 years (range 65-94 years). The mean follow-up was 5.4 years (range, 0.15-10 years). The mean preoperative Harris Hip Score was 51.3 ± 14 versus 88 ± 12, at the latest follow-up, and the mean Merle d'Aubigné hip functional score was 8 ± 3 versus 16.3 ± 2.91; patients (68 %) were alive at a mean of 7.2 years postoperatively (range, 5-10 years). Three revisions were documented for aseptic loosening. The overall survival rate at 7.2 years was 96.3 % (95 % confidence interval 92.2-100) using cup revision for aseptic loosening as the end point.

Computer-assisted total knee arthroplasty: impact of the surgeon's experience on the component placement.

INTRODUCTION: Accuracy of implant positioning in total knee arthroplasty (TKA) has a major impact on postoperative outcomes. We investigate the accuracy of positioning of multiples values simultaneously in TKA navigated, even among novice users. METHOD: The "novice" group included the first 91 knees operated on by 10 operators new to navigation and the "experienced" group 174 knees by an experienced navigator. Deviations from the preoperative planning were graded as optimal (≤3°), acceptable (4°-5°) or non-acceptable (≥5°). Moreover, the percentage of the three values fulfilling simultaneously the objective was calculated. RESULTS: No significant difference in the number of non-acceptable results was found. The common objective for these three values was achieved within 5° in 96 % in the novice group and 98 % in the experienced one. CONCLUSION: The satisfactory HKA alignment was not the result of reversed errors between the tibia and the femur, since it correlated the successful simultaneous results of alpha and beta angles.