Five-Year Follow-up of Knee Joint Distraction: Clinical Benefit and Cartilaginous Tissue Repair in an Open Uncontrolled Prospective Study

Abstract

Objective In end-stage knee osteoarthritis, total knee arthroplasty (TKA) may finally become inevitable. At a relatively young age, this comes with the risk of future revision surgery. Therefore, in these cases, joint preserving surgery such as knee joint distraction (KJD) is preferred. Here we present 5-year follow-up data of KJD. Design Patients ( n = 20; age <60 years) with conservative therapy resistant tibiofemoral osteoarthritis considered for TKA were treated. Clinical evaluation was performed by questionnaires. Change in cartilage thickness was quantified on radiographs and magnetic resonance images (MRI). The 5-year changes after KJD were evaluated and compared with the natural progression of osteoarthritis using Osteoarthritis Initiative data. Results Five-years posttreatment, patients still reported clinical improvement from baseline: ΔWOMAC (Western Ontario and McMaster Universities Arthritis Index) +21.1 points (95% CI +8.9 to +33.3; P = 0.002), ΔVAS (visual analogue scale score) pain -27.6 mm (95%CI -13.3 to -42.0; P < 0.001), and minimum radiographic joint space width (JSW) of the most affected compartment (MAC) remained increased as well: Δ +0.43 mm (95% CI +0.02 to +0.84; P = 0.040). Improvement of mean JSW (x-ray) and mean cartilage thickness (MRI) of the MAC, were not statistically different from baseline anymore (Δ +0.26 mm; P = 0.370, and Δ +0.23 mm; P = 0.177). Multivariable linear regression analysis indicated that KJD treatment was associated with significantly less progression in mean and min JSW (x-ray) and mean cartilage thickness (MRI) compared with natural progression (all Ps <0.001). Conclusions KJD treatment results in prolonged clinical benefit, potentially explained by an initial boost of cartilaginous tissue repair that provides a long-term tissue structure benefit as compared to natural progression. Level of evidence, II.

Is Knee Joint Distraction a Viable Treatment Option for Knee OA?—A Literature Review and Meta-Analysis

“…Three studies consisting of one cohort study and two randomized controlled trials were identified as meeting inclusion criteria [11][12][13] (►Fig. 1).…”

“…10 It is reported that this temporary mechanical unloading allows natural intrinsic repair processes to regenerate cartilaginous tissue evidenced by a sustained clinical benefit and increase in joint width space. 11 With KJD being a joint sparing procedure aimed at postponing a first prosthesis, successful clinical adoption could significantly improve patients' quality of life and thus reduce the long-term health care costs associated with knee OA.…”

Initial tissue repair predicts long-term clinical success of knee joint distraction as treatment for knee osteoarthritis

“…Despite the smaller initial JSW increase in patients who underwent TKA after KJD, their JSW was on average not decreased compared to baseline at the last measurement before TKA. This should be considered in the context of a general decrease in JSW over time as natural course of joint degeneration in case the disease remains untreated 7 .…”

“…MRI scans were performed with the Eckstein protocol 6,12 . The mean cartilage thickness over the subchondral bone area and the percentage of denuded subchondral bone area were calculated for the MAC 7 .…”

Design Evaluation of a Novel Multicompartment Unloader Knee Brace

“…The long-term effects may be greater; for example, the reduction in joint contact forces via weight loss, wedged insoles, unicompartment offloader braces, or high tibial osteotomy has been shown to reduce structural damage and improve tissue remodeling, increasing the potential of the joint to restore normal function [15]. A brace that is capable of unloading the knee joint may allow for improved soft-tissue repair [56], or be used as a rehabilitation tool to help improve strength and range of motion while weight-bearing. Rehabilitation protocols highlight the need for progressive weight bearing, passive extension, quadriceps control and neuromuscular training following knee procedures including meniscal repair [57], anterior cruciate ligament reconstruction [58], and articular cartilage repair [59][60][61][62][63][64], all of which may be aided by the TCU's powerful and adjustable knee extension assist mechanism.…”