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

Dong Jin Ryu; Sung-Sahn Lee; Eui Yub Jung; Joo Hwan Kim; Tae Soo Shin; Joon Ho Wang

doi:10.1177/23259671211034151

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

Orthop J Sports Med. 2021 Oct 5;9(10):23259671211034151. doi: 10.1177/23259671211034151. eCollection 2021 Oct.

Authors

Dong Jin Ryu¹, Sung-Sahn Lee², Eui Yub Jung³, Joo Hwan Kim⁴, Tae Soo Shin⁴, Joon Ho Wang^{3

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Affiliations

¹ Department of Orthopaedic Surgery, Inha University Hospital, Incheon, Republic of Korea.
² Department of Orthopaedic Surgery, Ilsan Paik Hospital, Inje University School of Medicine, Goyang-si, Republic of Korea.
³ Department of Orthopaedic Surgery, National Medical Center, Seoul, Republic of Korea.
⁴ Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
⁵ Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.
⁶ Department of Medical Device Management and Research, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.

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 × ΔJLCA _valgus . Upon simplification, the following equation showed the highest intermethod ICC value (0.991): Target correction angle - ⅓ΔJLCA _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.

Keywords: correction error; medial laxity; preoperative planning; proximal tibial osteotomy.