Joint line obliquity after lateral closing-wedge high tibial osteotomy does not adversely affect clinical and radiological outcome: a 5-year follow-up study

Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-023-07532-7 KNEE Joint line obliquity after lateral closing‑wedge high tibial osteotomy does not adversely affect clinical and radiological outcome: a 5‑year follow‑up study Tianshun Xie1 · Maarten R. Huizinga2 · Inge van den Akker‑Scheek1 · Hugo C. van der Veen1 · Reinoud W. Brouwer2 Received: 21 May 2023 / Accepted: 27 July 2023 © The Author(s) 2023 Abstract Purpose To analyze the association between change in knee joint line obliquity (KJLO) and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival after lateral closing-wedge high tibial osteotomy (HTO). Methods A cohort of 180 patients treated in one single hospital with lateral closing-wedge HTO was examined. KJLO was defined by the medial proximal tibial angle (MPTA). To assess the association between KJLO and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival, patient groups were defined: I, postoperative MPTA < 95.0°; II, postoperative MPTA ≥ 95.0°; A, MPTA change < 8.0°; B, MPTA change ≥ 8.0°. Propensity score matching was used for between-groups (I and II, A and B) covariates matching, including age, gender, preoperative lower limb alignment, preoperative medial joint space width (mJSW), preoperative Western Ontario and McMaster Universities osteoarthritis Index (WOMAC) score, wedge size, and postoperative follow-up time. Patient-reported outcome was assessed by the WOMAC questionnaire, radiological progression of osteoarthritis by mJSW and Kellgren–Lawrence (KL) grade progression (≥ 1) preoperatively and at follow-ups (> 2 years). Failure was defined as revision HTO or conversion to knee arthroplasty. Results After propensity score matching, groups I and II contained 58 pairs of patients and groups A and B contained 50 pairs. There were no significant differences in postoperative WOMAC score or surgical failure rate between groups I and II or between groups A and B (p > 0.05). However, the postoperative mJSW was significantly lower in group I than group II (3.2 ± 1.6 mm vs 3.9 ± 1.8 mm; p = 0.018) and in group A than group B (3.0 ± 1.7 mm vs 3.7 ± 1.5 mm; p = 0.040). KL grade progression rate was significantly higher in group I than group II (53.4% vs 29.3%; p = 0.008) and in group A than group B (56.0% vs 28.0%; p = 0.005). Conclusion Increased KJLO (postoperative MPTA ≥ 95.0°) or MPTA change ≥ 8.0° after lateral closing-wedge HTO does not adversely affect patient-reported outcome, radiological progression of osteoarthritis, or surgical survival at an average 5-year follow-up. Level of evidence III, retrospective cohort study. Keywords Joint line obliquity · Patient-reported outcome · Osteoarthritis progression · Surgical survival · Propensity score matching · Lateral closing-wedge high tibial osteotomy Abbreviations HKA Hip-knee-ankle angle HTO High tibial osteotomy * Tianshun Xie 1 Department of Orthopaedic Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands 2 Department of Orthopaedic Surgery, Martini Hospital, Groningen, The Netherlands JLCA Joint line convergence angle KJLO Knee joint line obliquity KL Kellgren and Lawrence KOOS Knee injury and Osteoarthritis Outcome Score KSS Knee Society Score mJSW Medial joint space width mLDFA Mechanical lateral distal femoral angle MPTA Medial proximal tibial angle PSM Propensity score matching WOMAC Western Ontario and McMaster Universities Osteoarthritis Index 13 Vol.:(0123456789) Knee Surgery, Sports Traumatology, Arthroscopy Introduction High tibial osteotomy (HTO) realigns the weight-bearing axis in the lower limb, providing a treatment option for medial knee osteoarthritis associated with varus alignment [31]. Two essential techniques are typically used: medial opening-wedge and lateral closing-wedge HTO [42]. However, every HTO creates a change in knee joint line obliquity (KJLO), and the medial proximal tibial angle (MPTA) can be used to describe the KJLO [11, 20, 37]. There is controversial evidence on the association between postoperative KJLO and patient-reported outcomes following medial opening-wedge HTO. Some studies suggest inferior postoperative patient-reported outcomes with an excessive postoperative KJLO [2, 20, 38], and other studies have found no significant difference in postoperative patient-reported outcomes between excessive and normal postoperative KJLO [10, 37, 40]. Additionally, limited research has explored this relationship after a lateral closing-wedge HTO. Understanding the link between the change in KJLO and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival is necessary when selecting the appropriate knee osteotomy to treat varus medial knee osteoarthritis. Some studies suggest a double-level osteotomy when a valgus-producing HTO is predicted to result in a postoperative MPTA exceeding 95° [20, 28]. However, this recommendation may not be warranted given the current controversy surrounding the association between postoperative KJLO and patient-reported outcomes. There is limited evidence on the associations between postoperative KJLO and radiological progression of osteoarthritis and surgical survival after HTO, highlighting the need for further research in this area. The purpose of this study is to analyze the associations between change in KJLO and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival after lateral closing-wedge HTO. Our hypothesis is that patients with excessive postoperative KJLO after lateral closing-wedge HTO will present poorer patientreported outcomes and higher rates of radiological osteoarthritis progression and surgical failure compared to those with normal postoperative KJLO. lateral closing-wedge HTO to treat symptomatic medial knee osteoarthritis with varus alignment. Patients were excluded if they (1) did not complete the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at postoperative follow-ups (> 2 years), (2) did not have preoperative or postoperative anteroposterior long-standing radiographs, or (3) had a postoperative anteroposterior long-standing radiograph filmed, but the film time was not within 6–18 months after HTO. After applying these exclusion criteria, a total of 180 patients were included in the analyses. This study design followed the statement of STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) for cohort studies [46] and was approved by the ethics committee of our hospital (MEC no. 2022–005). Lateral closing‑wedge HTO The lateral closing-wedge HTO was performed by a single experienced knee surgeon (RWB), in accordance with the procedure described by Huizinga et al. [13] and van Raaij et al. [44]. The procedure involved making an incision from the tibial tuberosity to the posterior aspe (...truncated)