The in-vivo medial and lateral collateral elongation correlated with knee functional score and joint space following unicompartmental knee arthroplasty

Chunjie Xia; Nan Zheng; Tianyun Gu; Huiyong Dai; Diyang Zou; Qi Wang; Tsung-Yuan Tsai

doi:10.1016/j.otsr.2024.104052

The in-vivo medial and lateral collateral elongation correlated with knee functional score and joint space following unicompartmental knee arthroplasty

Orthop Traumatol Surg Res. 2024 Nov 14:104052. doi: 10.1016/j.otsr.2024.104052. Online ahead of print.

Authors

Chunjie Xia¹, Nan Zheng², Tianyun Gu³, Huiyong Dai⁴, Diyang Zou², Qi Wang⁴, Tsung-Yuan Tsai⁵

Affiliations

¹ School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China; School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, China; Engineering Research Center for Digital Medicine of the Ministry of Education, Shanghai, China.
² School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, China; Engineering Research Center for Digital Medicine of the Ministry of Education, Shanghai, China; Shanghai Key Laboratory of Orthopaedic Implants & Clinical Translation R&D Center of 3D Printing Technology, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
³ School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, China.
⁴ Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
⁵ School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, China; Engineering Research Center for Digital Medicine of the Ministry of Education, Shanghai, China; Shanghai Key Laboratory of Orthopaedic Implants & Clinical Translation R&D Center of 3D Printing Technology, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address: tytsai@sjtu.edu.cn.

PMID: 39547306
DOI: 10.1016/j.otsr.2024.104052

Abstract

Background: The medial collateral ligament (MCL) and lateral collateral ligament (LCL) are paramount for joint stability. Their elongation patterns may change during fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (FB and MB UKA). This study aims to explore the relationship between the elongation of MCL, LCL, and changes in joint space, as well as their correlation with functional scale scores during FB and MB UKA.

Hypothesis: We hypothesize that MCL and LCL have different elongation patterns in UKA patients, and there is a correlation between elongation and joint space and functional scores.

Materials and methods: The study recruited 24 patients undergoing UKA on a unilateral knee (13 FB and 11 MB). A dual fluoroscopic imaging system was employed to assess in-vivo knee kinematics during static standing and single-leg lunge. The superficial and deep MCL (sMCL, dMCL) and LCL were divided into anterior, medium, and posterior portions. The virtual ligament method quantified in-vivo ligament lengths. Analysis focused on the correlation of normalized ligament lengths with functional scores and joint space.

Results: 1. LCL Elongation in FB UKA: There is a significant increase in LCL elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 2. MCL Elongation in MB UKA: Both sMCL and dMCL exhibit significant elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 3. Correlation with Functional Scores: Differences in collateral ligament elongation in FB UKA are significantly correlated with the OKS and KSS, highlighting the impact on functional outcomes. In MB UKA, differences in ligament elongation are significantly correlated with the FJS. 4. Joint Space Correlation: There is a significant correlation between the elongation of the anterior and medium portions of dMCL and joint space in the surgical compartment during mid- and deep flexion (30-100°, p < 0.05, r > 0.64).

Conclusion: The study reveals distinct ligament elongation patterns between UKA and native knees in LCL for FB UKA and MCL for MB UKA. These patterns are associated with knee functional scores. Moreover, dMCL elongation correlates significantly with the joint space for MB UKA during middle and deep flexion phases.

Level of evidence: III; prospective retrospective cohort study.

Keywords: In-vivo; Lateral collateral ligament; Ligament length; Medial collateral ligament; Unicompartmental knee arthroplasty.