Reliability of Preoperative Planning Method That Considers Latent Medial Joint Laxity in Medial Open-Wedge Proximal Tibial Osteotomy

Abstract

Background: Soft tissue laxity around the knee joint has been recognized as a crucial factor affecting correction error during medial open-wedge proximal tibial osteotomy (MOWPTO). Medial laxity in particular, which represents the changes in joint-line convergence angle (JLCA), affects soft tissue correction. Purpose: The purpose of this study was to quantify medial laxity and develop a preoperative planning method that considers medial laxity. Study Design: Cohort study; Level of evidence, 3. Methods: This study retrospectively reviewed 139 knees in 117 patients who underwent navigation-assisted MOWPTO from January 2014 to July 2019 for symptomatic medial compartment osteoarthritis with varus alignment >5°. We compared the results of 2 preoperative planning methods: conventional Miniaci (n = 47) and latent medial laxity reduction (LMLR) (n = 92). We evaluated the incidence of undercorrection, acceptable correction, and overcorrection. The radiologic parameters were analyzed using multiple linear regression with a stepwise selection model to establish an equation for the optimal preoperative planning method. The intraclass correlation coefficients (ICCs) of intraobserver, interobserver, and intermethod reliability were calculated. Results: The Miniaci method showed a higher incidence of overcorrection (55.3%) than the LMLR method (22.8%) at postoperative 6 months ( P = .0006). Multiple linear regression with a stepwise selection model revealed a high correlation coefficient ( R 2 = 0.888) for the following equation: Adjusted planned correction angle = 0.596 + 0.891 × Target correction angle – 0.255 × Δ JLCA valgus. Upon simplification, the following equation showed the highest intermethod ICC value (0.991): Target correction angle – ⅓Δ JLCA valgus, while the Miniaci method showed a relatively low ICC value of 0.875. Conclusion: There was a risk of overcorrection after MOWPTO using the conventional Miniaci method. An equation that considers medial laxity may help during preoperative planning for optimal correction during MOWPTO.

Preoperative joint line convergence angle correction is a key factor in optimising accuracy in varus knee correction osteotomy

“…Similarly, in a comparative study including navigation‐guided osteotomy correction, Schroeter et al failed to achieve an accuracy of ± 1.5° divergence of the preoperatively planned and postoperatively achieved mTFA correction [37]. These findings point out a significant limitation of osteotomies to date, and further literature reports about a rate of malcorrection of 30–40%, which critically depends on the definition of malcorrection [32, 33, 35, 37, 38]. Studies reporting a low rate of malcorrection often defined a much wider corridor concerning the postoperative WBL ratio that was considered satisfying [20].…”

“…As in this study, previous work has identified increased preoperative JLCA as a risk factor for postoperative overcorrection [ 33 , 40 ]. Significant effort was made to mathematically estimate the change in the JLCA from pre to postoperatively, between supine and weight-bearing radiographs, and with and w/o stress radiographs [ 7 , 25 , 35 ]. JLCA change from the pre- to the postoperative conditions becomes even more challenging since it is clinically established to perform a medial release to unload the medial compartment effectively [ 2 ].…”

Does the anteromedial plate position affect proximal screw length and worsen the clinical outcomes in medial opening wedge high tibial osteotomy?

“…The surgical technique followed the procedure previously described by Kyung and Ryu et al [ 19 , 20 ]. Two senior expert surgeons (JHW and DHL) performed all MOWHTO procedures.…”

“…The targeted postoperative mechanical axis was 2–3° valgus [ 21 ]. The amount of coronal correction was determined preoperatively planning on the base of the standing whole leg, varus, and valgus stress radiograph [ 20 , 22 ]. All osteotomies were performed in a biplanar fashion.…”

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy

“…The difference in JLCA between supine and standing positions has been reported as the most significant factor for correction errors [13,16]. 'Latent medial laxity', defined as the difference between the preoperative JLCA in the standing position and the JLCA in the valgus stress radiographs, has been reported to be a significant factor [12,15]. Prediction models have been applied to predict changes in JLCA [11,12]; however, the explanatory power of these models is insufficient for clinical use.…”