CPAK classification detect the real knee joint apex position in less than half of the knees.

PURPOSE: Accurate assessment of the knee joint line is essential for surgeries involving the knee. The knee joint line obliquity (KJLO) is a radiological measurement that evaluates the position of the knee joint relative to the ground and is frequently used in preoperative planning and clinical follow-up. On the other hand, coronal plane alignment of the knee (CPAK) classifications assesses the joint line as the summation of the medial proximal tibial angle (MPTA) and mechanical lateral distal femoral angle (mLDFA). The purpose of this study is to determine the concordance of these two measurement techniques. METHODS: This cross-sectional study evaluated the long-leg standing radiographs (LSRs) of 164 healthy knees. The extremity KJLO and CPAK classification JLO were measured twice by two observers at 8-week intervals. The knee joint line apex positions (proximal, neutral and distal) of the two measurement techniques are compared (concordance or discordant). The intraobserver and interobserver reliability were examined using the intraclass correlation coefficient (ICC). Possible causes of the discordant were evaluated with univariate and multivariate logistic regression analysis. RESULTS: CPAK classification detected the KJLO apex position in 70 extremities (42.7%) only. Subgroups CPAK JLO detected 13.6% of the proximal apex, 20.4% of the neutral, and 90.7% of the distal apex (p < 0.01). Upon multivariate logistic regression analysis, the variable KJLO apex position (proximal, neutral vs. distal, odds ratio (OR) = 10.291, 95% confidence interval [CI] = 2.225-25.656, and (p < 0.01) was determined as a risk factor for discordant. CONCLUSION: The CPAK JLO measurement technique can be misleading in defining the KJLO apex position and the concordance between them is less than 50%. It has a high tendency to misleadingly predict proximal and neutral apex positions, which can potentially have negative implications for assessing the joint line. LEVEL OF EVIDENCE: Level I.

Opening wedge high tibial osteotomy allows better outcomes than unicompartmental knee arthroplasty in patients expecting to return to impact sports.

PURPOSE: Prior studies have compared unicompartmental knee arthroplasty (UKA) with high tibial osteotomy (HTO) suggesting that both procedures had good functional outcomes. But none had established the superiority of one of the two procedures for patients with high expectation including return to impact sport. The aim of this study was to compare functional outcomes and ability to return to impact sport of active patients defined with a pre-arthritis University of California and Los Angeles activity (UCLA) score > 8, after UKA or HTO procedures. METHODS: A retrospective review of patients with a pre-arthritis UCLA score > 8 operated between January 2014 and September 2017 has identified 91 patients with open-wedge HTO and 117 patients with UKA. A matching process based on age (± 3 years) and gender allowed to include 50 patients in each group for comparative analysis. Patient reported outcomes included Knee Osteoarthritis Outcomes Score (KOOS), UCLA Score, Knee Society Score (KSS) and time to return to sport or previous professional activities at 3, 6, 12 and 24 months following surgery. RESULTS: Mean time to return to sport activities or previous professional activities were significantly lower for the HTO group than for UKA group [respectively, 4.9 ± 2.2 months for HTO group vs 5.8 ± 6.2 months for UKA group (p = 0.006) and 3 ± 3 months for HTO group vs 4 ± 3 months for UKA group (p = 0.006)]. At 24-month follow-up, UCLA score, KOOS Sports Sub-score and KSS activity score were significantly higher for HTO group than for UKA group (Δ: 2 CI 95% (1.3-2.5 points) p < 0.0001, (Δ: 10.9 CI 95% (2.9-18.9 points) p = 0.04 and Δ: 7.8 CI 95% (2.4-13.4 points) p = 0.006, respectively) and 31 patients (62%) were practicing impact sport in the HTO group versus 14 (28%) in the UKA group (odd-ratio 4.2 CI 95% (1.8-9.7) p < 0.0001). CONCLUSION: HTO offers statistically significant quicker return to sport activities and previous professional activities with a higher rate of patients able to practice impact activity (62% for HTO vs 28% for UKA) and better sports related functional scores at two years after surgery compared to UKA. LEVEL OF EVIDENCE: III retrospective case-control study.

A protective hinge wire, intersecting the osteotomy plane, can reduce the occurrence of perioperative hinge fractures in medial opening wedge osteotomy.

PURPOSE: A recent study reported that positioning a K-wire to intersect the cutting plane at the theoretical lateral hinge location increases the lateral hinge's resistance to fracture during the opening of opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to evaluate the clinical relevance of the use of this K-wire and its benefits in terms of lateral hinge protection during OWHTO in daily practice. METHODS: A retrospective comparative study identified 206 patients who underwent OWHTO from January 2014 to December 2017. Among these patients, 71 had an additional K-wire (HK + group), whereas 135 did not (HK- group). The subjects meeting the inclusion criteria were included in a matched pairing process, which identified 60 patients in the HK + group and 60 patients in the HK- group. Mean follow-up time was 2.3 ± 1.0 years (range 2-4.2). Radiographic outcomes were evaluated with intraoperative and postoperative fluoroscopic imaging and with CT imaging at 6 weeks post OWHTO surgery. The knee osteoarthritis outcomes score (KOOS) was used and time needed to return to work and any kind of sports was collected. RESULTS: Thirty six patients (30%) were found to have a LHF. Among these patients, 26 (72%) did not have an additional K-wire positioned at their theoretical lateral hinge location (HK- group) during the procedure. LHF rate for patients without additional K-wire group (HK-) was 43.3%, whereas it was 16.7% for the patients with an additional K-wire (HK +) [Odd ratio 3.8 95% CI 1.6-8.3; p = 0.005]. The mean time to return to work, return to any kind of sports, and bone union was significantly shorter for HK + group (p < 0.05). CONCLUSION: This study demonstrated that during OWHTO, positioning a K-wire intersecting the cutting plane at the theoretical lateral hinge location reduced the number of intraoperative lateral hinge fractures. LEVEL OF EVIDENCE: III retrospective case-control study.

Long-term results of cementless total hip arthroplasty for the treatment of ankylosed hip.

PURPOSE: The purpose of this study was to report the long-term results of total hip arthroplasty (THA) for the treatment of ankylosed hip. METHODS: Twenty-nine consecutive THAs were performed in 26 patients. The mean age of the patients at the time of the operation was 43.3 years (range, 19-69 years). We used cementless fixation in all hips and the mean duration of follow-up was 10.1 years (range, 4.5-20 years). Radiological evaluation of components, osteolysis, radiolucent lines and loosening were assessed. The Harris Hip Score (HHS), range of motion (ROM), limb-length discrepancy and walking capacity with or without any support were used preoperatively and at final follow-up for clinical evaluation. Survivorship analysis was conducted using the Kaplan-Meier method using second revision for any reason as the endpoint. RESULTS: The mean HHS was 85.6 (range, 55-98) points and mean ROM was 110.5° for flexion. The mean limb-length discrepancy improved from 4.1 cm to 1.1 cm. Positive Trendelenburg sign was recorded in 31% of the patients and 24% of patients needed any support for walking postoperatively. We observed surgical complications related to abductor arm in 25% of the patients. Radiolucency on the acetabular side was seen on one or more zones in 15 patients (16 hips). One aseptic acetabular component loosening was observed. On the femoral side, 11 patients demonstrated non-progressive radiolucent lines and osteolysis around the stem was seen in four hips but there was no aseptic stem loosening. The Kaplan-Meier survival rate considering revision for any reason as the endpoint was 81.5%, for aseptic loosening 91.3%, for a worst-case scenario of 66.4% at 10 years. CONCLUSION: Cementless fixation showed good to excellent results at 10 years. Preoperative and postoperative abductor status of the patient is critical for patient satisfaction.