Changes in Cartilage Thickness and Denuded Bone Area after Knee Joint Distraction and High Tibial Osteotomy-Post-Hoc Analyses of Two Randomized Controlled Trials.

Mylène P Jansen,Susanne Maschek,Floris P J G Lafeber,Felix Eckstein,Simon C Mastbergen,Wolfgang Wirth,Ronald J Van Heerwaarden

doi:10.3390/jcm10020368

Abstract

High tibial osteotomy (HTO) and knee joint distraction (KJD) are joint-preserving treatments that unload the more affected compartment (MAC) in knee osteoarthritis. This post-hoc study compares two-year cartilage-thickness changes after treatment with KJD vs. HTO, and identifies factors predicting cartilage restoration. Patients indicated for HTO were randomized to KJD (KJDHTO) or HTO treatment. Patients indicated for total knee arthroplasty received KJD (KJDTKA). Outcomes were the MRI mean MAC cartilage thickness and percentage of denuded bone area (dABp) change two years after treatment, using radiographic joint space width (JSW) as the reference. Cohen’s d was used for between-group effect sizes. Post-treatment, KJDHTO patients (n = 18) did not show significant changes. HTO patients (n = 33) displayed a decrease in MAC cartilage thickness and an increase in dABp, but an increase in JSW. KJDTKA (n = 18) showed an increase in MAC cartilage thickness and JSW, and a decrease in dABp. Osteoarthritis severity was the strongest predictor of cartilage restoration. Kellgren–Lawrence grade ≥3 showed significant restoration (p < 0.01) after KJD; grade ≤2 did not. Effect sizes between severe KJD and HTO patients were large for MAC MRI cartilage thickness (d = 1.09; p = 0.005) and dABp (d = 1.13; p = 0.003), but not radiographic JSW (d = 0.28; p = 0.521). This suggests that in knee osteoarthritis patients with high disease severity, KJD may be more efficient in restoring cartilage thickness.

Highlights

Knee osteoarthritis (OA) is the most prevalent form of OA and one of the most common causes of disability worldwide [1]
In the high tibial osteotomy (HTO) group, one patient was excluded before treatment due to anxiety, four patients were lost to follow-up because of comorbidities interfering with follow-up, two patients did not undergo an MRI at two years, two patients had MRI scans with different hardware at baseline and two years, and four patients had MRI scans of insufficient quality, leaving 33 patients for analysis
The main goal of this study was to compare two-year quantitative cartilage changes during treatment with knee joint distraction (KJD) vs. HTO; we hypothesized that KJD is more effective in restoring cartilage in the more affected compartment (MAC), while avoiding negative effects on the less affected compartment (LAC)

Summary

Introduction

Knee osteoarthritis (OA) is the most prevalent form of OA and one of the most common causes of disability worldwide [1] It poses a major global burden, and is anticipated to increase in the future [2,3]. In younger and more active patients, it involves a risk of failure, and future revision surgery In these cases, a joint-preserving alternative may be a desired option [6]. HTO permanently unloads the more affected compartment (MAC) of the tibio-femoral joint by (over-)correcting the leg axis. This puts more load on the less affected compartment (LAC), and has shown good long-term survival [12,13]. A direct measurement of cartilage structure is required to evaluate whether HTO has a positive effect on maintenance of cartilage tissue

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