Knee Joint Distraction Compared with High Tibial Osteotomy and Total Knee Arthroplasty: Two-Year Clinical, Radiographic, and Biochemical Marker Outcomes of Two Randomized Controlled Trials

Two-year post-distraction cartilage-related structural improvement is accompanied by increased serum full-length SIRT1

BACKGROUND

Previously, fragments from Sirtuin 1 (SIRT1) were identified in preclinical and clinical samples to display an increase in serum levels for N-terminal (NT) SIRT1 vs. C-terminal (CT) SIRT1, indicative of early signs of OA. Here we tested NT/CT SIRT1 levels as well as a novel formulated sandwich assay to simultaneously detect both domains of SIRT1 in a manner that may inform us about the levels of full-length SIRT1 in the circulation (flSIRT1) of clinical cohorts undergoing knee joint distraction (KJD).

METHODS

We employed an indirect ELISA assay to test NT- and CT-SIRT1 levels and calculated their ratio. Further, to test flSIRT1 we utilized novel antibodies (Ab), which were validated for site specificity and used in a sandwich ELISA method, wherein the CT-reactive served as capture Ab, and its NT-reactive served as primary detection Ab. This method was employed in human serum samples derived from a two-year longitudinal study of KJD patients. Two-year clinical and structural outcomes were correlated with serum levels of flSIRT1 compared to baseline.

RESULTS

Assessing the cohort, exhibited a significant increase of NT/CT SIRT1 serum levels with increased osteophytes and PIIANP/CTX-II at baseline, while a contradictory increase in NT/CT SIRT1 was associated with less denuded bone, post-KJD. On the other hand, flSIRT1 exhibited an upward trend in serum level, accompanied by reduced denuded bone for 2-year adjusted values. Moreover, 2 year-adjusted flSIRT1 levels displayed a steeper linear regression for cartilage and bone-related structural improvement than those observed for NT/CT SIRT1.

CONCLUSIONS

Our data support that increased flSIRT1 serum levels are a potential molecular endotype for cartilage-related structural improvement post-KJD, while NT/CT SIRT1 appears to correlate with osteophyte and PIIANP/CTX-II reduction at baseline, to potentially indicate baseline OA severity.

Unicompartmental osteoarthritis: High survival rate with a combined mechanical and biological salvage approach as alternative to metal resurfacing: Results at minimum 10 years of follow-up

PURPOSE

The aim of this study was to prospectively evaluate the long-term clinical results and failure rate of patients treated with complex salvage procedures using a combined mechanical and biological approach to address unicompartmental knee osteoarthritis (OA) and postpone the need for joint replacement.

METHODS

Thirty-nine patients (40.3 ± 10.9 years old) affected by unicompartmental OA (Kellgren-Lawrence 3) in stable joints underwent a personalized surgical treatment depending on the specific requirements of the affected compartment, including high tibial osteotomy, osteochondral scaffold, meniscal scaffold and meniscal allograft transplantation. Patients were evaluated with the International Knee Documentation Committee (IKDC), Visual Analogue Scale (VAS) and Tegner scores before surgery, at 3 years and a minimum of 10 years of follow-up.

RESULTS

A significant improvement was observed over time in all scores but worsened at the final follow-up. The IKDC subjective score improved from 46.9 ± 16.2 to 79.8 ± 16.4 at 3 years (p < 0.0005) and then decreased to 64.5 ± 21.4 (p = 0.001) at 12 years. A similar trend was confirmed for VAS and Tegner scores. Only two patients subsequently underwent knee arthroplasty, and nine more patients were considered clinical failure, for a cumulative surgical and clinical failure rate of 28.2% at the final follow-up.

CONCLUSION

A personalized, joint-preserving, combined mechanical and biological approach, addressing alignment as well as meniscal and cartilage lesions, is safe and effective, providing a clinical benefit and delaying the need for arthroplasty in young patients affected by unicompartmental knee OA. At the final evaluation, the clinical improvement decreased, but more than two-thirds of the patients still benefited from this treatment at a long-term follow-up.

LEVEL OF EVIDENCE

Level IV case series.

Comparison of Clinical Efficacy and Mechanical Characteristics of Two Knee Distraction Devices With Relevance for Clinical Practice

OBJECTIVE

Distraction treatment for severe osteoarthritis below the age of 65 successfully postpones arthroplasty. Most patients have been treated with a general external fixator or a device specifically intended for knee distraction. This study compares clinical efficacy of both devices in retrospect and their mechanical characteristics.

DESIGN

Clinical efficacy 2 years posttreatment was compared using retrospective data from patients with severe knee osteoarthritis treated with knee distraction; 63 with the Dynamic Monotube (Stryker GmbH, Switzerland) and 65 with the KneeReviver (ArthroSave BV, the Netherlands). Changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and function, general well-being (SF-36), cartilage thickness by radiographic joint space widening, and adverse events during treatment were assessed. Axial stiffness of clinically feasible configurations was assessed by bench testing for the Dynamic Monotube triax system and the KneeReviver.

RESULTS

No differences were observed in clinical efficacy, nor in mechanical characteristics and adverse events between the two devices. Although with large variation, both showed a clinically relevant improvement. In mechanical testing, contact between articular surfaces was observed for both devices at physiological loading. Stiffness of applied configurations strongly varied and primarily depended on bone pin length.

CONCLUSIONS

Patients treated with a general intended-use device or a distraction-specific device both experienced clinical and structural efficacy although with significant variation between patients. The latter may be the result of varying mechanical characteristics resulting from differences in clinical configurations of the devices and actual loading. The exact role of full/partial mechanical unloading of the joint during distraction treatment remains unclear.

Risk of Arthroplasty in Patients with Subchondral Insufficiency Fractures of the Knee: A Matched Study of the Implantable Shock Absorber using a Validated Predictive Model

Subchondral insufficiency fractures of the knee (SIFK) can result in high rates of osteoarthritis and arthroplasty. The implantable shock absorber (ISA) implant is a titanium and polycarbonate urethane device which reduces the load on the medial compartment of the knee by acting as an extra-articular load absorber while preserving the joint itself. The purpose of this study was to evaluate whether partially unloading the knee with the ISA altered the likelihood of progression to arthroplasty utilizing a validated predictive risk model (SIFK score). A retrospective case-control (2:1) study was performed on patients with SIFK without any previous surgery and on those implanted with the ISA with the primary outcome being progression to arthroplasty compared with nonoperative treatment at 2 years. Baseline and final radiographs, as well as magnetic resonance imagings, were reviewed for the evaluation of meniscus or ligament injuries, insufficiency fractures, and subchondral edema. Patients from a prospective study were matched using the exact SIFK Score, a validated predictive score for progression to arthroplasty in patients with SIFK, to those who received the ISA implant. Kaplan-Meier analysis was conducted to assess survival. A total of 57 patients (38 controls:19 ISA) with a mean age of 60.6 years and 54% female were included. The SIFK score was matched exactly between cases and controls for all patients. The 2-year survival rate of 100% for the ISA group was significantly higher than the corresponding rate of 61% for the control group (p < 0.01). In ISA, 0% of the patients converted to arthroplasty at 2 years, and 5% (one patient) had hardware removal at 1 year. When stratified by risk, the ISA group did not have a significantly higher survival compared with low-risk (p = 0.3) or medium-risk (p = 0.2) controls, though it had a significantly higher survival for high-risk groups at 2 years (100 vs. 15%, p < 0.01). SIFK of the medial knee can lead to significant functional limitation and high rates of conversion to arthroplasty. Implants such as the ISA have the potential to alter the progression to arthroplasty in these patients, especially those at high risk.

New concept of orthosis treatment for knee osteoarthritis: Clinical and radiological outcomes

BACKGROUND

Given the increasing numbers of young patients with knee osteoarthritis there is a need for treatments that can postpone a joint prosthesis (total knee replacement).

OBJECTIVE

As an alternative to the effective yet invasive knee joint distraction procedure, a knee orthosis was developed aiming to unload the affected knee and improving synovial fluid flow. The aim of this study was to examine the effectiveness of using a load-reducing orthosis for two months on functioning, pain, and disease progression (e.g. amount of damaged cartilage) in patients with symptomatic osteoarthritis of the knee for at least one year.

METHODS

This is an interventional single-center pilot study. Ten patients with symptomatic osteoarthritis of one knee (5 males/5 females; median age 57; age range 42-59) used a custom-made orthosis for 60 days during daily life activities that involved knee loading (e.g. standing, walking, but not during stair climbing). Cycling was not allowed. Clinical outcomes were assessed up to 24 months after intervention at 6 timepoints using patient reported-outcome measures Western Ontario and McMaster Universities Osteoarthritis (WOMAC) range 0-100; Visual Analogue Scale (VAS), range 0-100 for pain. Minimum joint space width (mJSW) was assessed using knee images digital analysis (KIDA) and articular cartilage volume with magnetic resonance imaging (MRI) using custom software at baseline and at 12 and 24 months follow-up.

RESULTS

Clinically beneficial effects were found for functioning (WOMAC improvement compared to baseline ranged between 18 points at 3 months follow-up and 31 points at 12 months follow-up, with only the 24-months follow-up (improvement of 27 points) not reaching statistical significance (p< 0.05)) and for pain (VAS improvement compared to baseline at follow-up time points ranged between 41-56 points; all p< 0.05). No improvements in mJSW- or MRI-derived parameters were found.

CONCLUSION

This study demonstrates that use of a custom-made knee-unloading orthosis for 60 days can result in improved functional ability and decrease in pain in relatively young patients with knee osteoarthritis. No effect on disease progression could be evidenced.

Failure of cartilage regeneration: emerging hypotheses and related therapeutic strategies

Osteoarthritis (OA) is a disabling condition that affects billions of people worldwide and places a considerable burden on patients and on society owing to its prevalence and economic cost. As cartilage injuries are generally associated with the progressive onset of OA, robustly effective approaches for cartilage regeneration are necessary. Despite extensive research, technical development and clinical experimentation, no current surgery-based, material-based, cell-based or drug-based treatment can reliably restore the structure and function of hyaline cartilage. This paucity of effective treatment is partly caused by a lack of fundamental understanding of why articular cartilage fails to spontaneously regenerate. Thus, research studies that investigate the mechanisms behind the cartilage regeneration processes and the failure of these processes are critical to instruct decisions about patient treatment or to support the development of next-generation therapies for cartilage repair and OA prevention. This Review provides a synoptic and structured analysis of the current hypotheses about failure in cartilage regeneration, and the accompanying therapeutic strategies to overcome these hurdles, including some current or potential approaches to OA therapy.

Joint distraction using a purpose-built device for knee osteoarthritis: a prospective 2-year follow-up

OBJECTIVE

Knee distraction treatment for end-stage osteoarthritis successfully postpones arthroplasty for years. Studies performed thus far used general intended use, patient-personalised or custom-made devices. In this study, for the first time, a device specifically designed for knee distraction is evaluated.

DESIGN

65 patients (≤65 years) with end-stage knee osteoarthritis indicated for arthroplasty received knee distraction. Before, 1-year and 2-year post-treatment, questionnaires were filled out and knee radiographs made. Adverse events and self-reported pain medication were registered.

RESULTS

Forty-nine patients completed 2-year follow-up: one patient did not complete treatment, three patients received arthroplasty in the first and four patients in the second year follow-up. Eight patients were lost to follow-up in the second year. The total Western Ontario and McMaster Universities Osteoarthritis Index score showed a clinically relevant improvement at 1 and 2 years (+26 and +24 points), as did all subscales (all p<0.001). The minimum radiographic joint space width improved over 1 (+0.5 mm; p<0.001) and 2 (+0.4 mm; p=0.015) years, as did the physical Short-Form 36 (+10 points; p<0.001). The most common adverse event was pin tract infection, experienced by 66% of patients, in 88% successfully treated with oral antibiotics. In two cases, hospitalisation and/or intravenous antibiotics were needed. Eight patients experienced device-related complications. None of the complications influenced 2-year outcomes. Before treatment, 42% of patients used pain medication, which had nearly been halved 1 (23%; p=0.02) and 2 years (29%; p=0.27) post-treatment.

CONCLUSIONS

Patients treated with a general applicable, for knee distraction purpose-built device showed, despite adverse events, significant clinical and structural improvement over 2 years.

TRIAL REGISTRATION NUMBER

NL7986.

Surgical interventions for symptomatic knee osteoarthritis: a network meta-analysis of randomized control trials

BACKGROUND

Multiple surgical interventions exist for the treatment of symptomatic knee osteoarthritis, but the surgeon and patient may often have difficulty deciding which interventions are the best option.

METHODS

We conducted a systematic review to identify randomized clinical trials (RCTs) that compared complications, revisions, reoperations, and functional outcomes among TKA (total knee arthroplasty), UKA (unicompartmental knee arthroplasty), HTO (high tibial osteotomy), BCA (bicompartmental knee arthroplasty), BIU (bi-unicompartmental knee arthroplasty), and KJD (knee joint distraction). The PubMed, Embase, and Cochrane databases were reviewed for all studies comparing two or more surgical interventions. Direct-comparison meta-analysis and network meta-analysis (NMA) were performed to combine direct and indirect evidence. The risk of bias was assessed using the revised Cochrane risk of bias tool for RCTs.

RESULTS

This NMA and systematic review included 21 studies (17 RCTs), with a total of 1749 patients. The overall risk-of-bias assessment of the RCTs revealed that 7 studies had low risk, 5 had some concerns, and 9 had high risk. SUCRA (the surface under the cumulative ranking curve) rankings revealed that KJD had the greatest risk of appearing postoperative complications, revisions, and reoperations, and UKA or TKA had the lowest risk. The majority of comparisons among various treatments showed no difference for functional outcomes.

CONCLUSION

Each surgical intervention is noninferior to other treatments in functional outcomes, but UKA and TKA are better options to treat OA according to SUCRA rankings by comparing complications, revisions, and reoperations. KJD is an imperfect option for treating OA. Other treatments should be carefully considered for each patient in accordance with their actual conditions. However, this conclusion is limited by the selection of reviewed publications and individual variation of surgical indications for patients.

TRIAL REGISTRATION

This study was registered with Research Registry (reviewregistry1395).

Analysis of the determinant factor of the medial joint space width after medial opening wedge high tibial osteotomy

INTRODUCTION

The decrease in the medial joint space width (MJSW) in patients with osteoarthritis (OA) is proportional to the degree of arthritis. The purpose of this study was to evaluate the affecting factors of the MJSW by serial radiologic assessment after medial open wedge high tibial osteotomy (MOW-HTO).

MATERIALS AND METHODS

Between March 2014 and March 2019, 162 MOW-HTO knees that underwent serial radiologic assessment and follow-up MRI were enrolled. Changes in the MJSW were analyzed by dividing into three groups: group I, low quartile (< 25%); II, middle quartile (25-75%); and III, high quartile (> 75%), according to the magnitude of the MJSW. The correlation between the MJSW and weight-bearing line ratio (WBLR), hip knee ankle angle (HKA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (m-LDFA), joint line orientation angle (JLOA), and MRI cartilage status was analyzed. Multiple linear regression analysis was used to analyze factors affecting the amount of change in the MJSW. The clinical outcome was also correlated with the MJSW.

RESULTS

The amount of change in the JLCA, which has the largest beta value (weight-bearing standing anteroposterior (AP) view and 45° flexion posteroanterior view (Rosenberg view) β =  - 0.699 and β = -5.221, both p < 0.001, respectively), had the greatest contribution to the change in the MJSW. The WBLR was also related (standing AP and Rosenberg β = 0.177 and β = 0.264, p = 0.015 and p = 0.004, respectively). There was no statistical difference between the amount of change in the MJSW and the change in cartilage. The clinical outcomes did not differ between the groups.

CONCLUSION

The JLCA was the most important contributing factor for the MJSW, followed by WBLR. This contribution was more pronounced in Rosenberg view than standing AP view. Changes in cartilage status were not related to the MJSW and JLCA. The clinical outcome was not related to the MJSW, either. Level of evidence Cohort study; level III.

The Current Role of Disease-modifying Osteoarthritis Drugs

Contemporary treatments for osteoarthritis (OA) pursue only to alleviate the pain caused by the illness. Discovering disease-modifying osteoarthritis drugs (DMOADs) that can induce the repair and regeneration of articular tissues would be of substantial usefulness. The purpose of this manuscript is to review the contemporary role of DMOADs in managing OA. A narrative literature review on the subject, exploring the Cochrane Library and PubMed (MEDLINE) was performed. It was encountered that many publications have analyzed the impact of several DMOAD methods, including anti-cytokine therapy (tanezumab, AMG 108, adalimumab, etanercept, anakinra), enzyme inhibitors (M6495, doxycycline, cindunistat, PG-116800), growth factors (bone morphogenetic protein-7, sprifermin), gene therapy (micro ribonucleic acids, antisense oligonucleotides), peptides (calcitonin) and others (SM04690, senolitic, transient receptor potential vanilloid 4, neural EGFL-like 1, TPCA-1, tofacitinib, lorecivivint and quercitrin). Tanezumab has been demonstrated to alleviate hip and knee pain in individuals with OA but can cause major adverse events (osteonecrosis of the knee, rapid illness progression, augmented prevalence of total joint arthroplasty of involved joints, particularly when tanezumab is combined with nonsteroidal anti-inflammatory drugs. SM04690 (a Wnt inhibitor) has been demonstrated to be safe and efficacious in alleviating pain and ameliorating function as measured by the Western Ontario and McMaster Universities Arthritis Index. The intraarticular injection of lorecivivint is deemed safe and well tolerated, with no important reported systemic complications. In conclusion, even though DMOADs seem promising, their clinical effectiveness has not yet been demonstrated for managing OA. Until forthcoming studies can proved the medications' capacity to repair and regenerate tissues affected by OA, physicians should keep using treatments that only intend to alleviate pain.

Artificial Intelligence in osteoarthritis: repair by knee joint distraction shows association of pain, radiographic and immunologic outcomes

OBJECTIVES

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. The current objective was to analyze radiographic changes after KJD using an automatic AI-based measurement method, and relate these to clinical outcome and SF markers.

METHODS

20 knee osteoarthritis patients were treated with KJD in regular care. Radiographs and WOMAC were collected before and ∼1-year post-treatment. SF was aspirated before, during, and after treatment; biomarker levels were assessed by immunoassay. Radiographs were analyzed to obtain compartmental minimum and standardized joint space width (JSW), Kellgren-Lawrence (KL) grades, compartmental joint space narrowing (JSN) scores, and osteophytosis and sclerosis scores. Results were analyzed for the most (MAC) and least affected compartment. Radiographic changes were analyzed using Wilcoxon Signed Rank tests for categorical and paired t-test for continuous variables. Linear regression was used to calculate associations between changes in JSW, WOMAC pain, and SF markers.

RESULTS

16 Patients could be evaluated. JSW, KL and JSN improved in around half of the patients, significant only for MAC JSW (p< 0.05). MAC JSW change was positively associated with WOMAC pain change (p< 0.04). Greater MCP-1 and lower TGFβ-1 increases were significantly associated with changes in MAC JSW (p< 0.05). MCP-1 changes were positively associated with WOMAC pain changes (p< 0.05).

CONCLUSION

Automatic radiographic measurements show improved joint structure in most patients after KJD in regular care. MAC JSW increased significantly and was associated with SF biomarker level changes and even with improvements in pain as experienced by these patients.

Precise Patellar Tendon Insertion Protection and Osteotomy Surface Advantage of Transtibial Tuberosity-High Tibial Osteotomy

OBJECTIVE

Medial opening wedge high tibial osteotomy (HTO) is successful in the treatment of knee osteoarthritis with medial compartment stenosis and tibial varus deformity, but patella infera is the main complication. This study aims to design a new medial tibial open osteotomy scheme, transtibial tuberosity-high tibial osteotomy (TT-HTO), which can fully protect the patellar tendon insertion. In addition, the area of the osteotomy surface and wedge volume were evaluated in TT-HTO, biplanar distal tibial tuberosity osteotomy (biplanar-DTO), and uniplanar-DTO to evaluate the potential advantages of this technology in bone healing.

METHODS

The tibial tubercle was divided into four equal sections from proximal to distal, which were defined as zones A, B, C, and D. From September to December 2020, the imaging examinations of 200 patients (95 males and 105 females) with a mean age of 40.6 years (range 19-60 years) were evaluated to observe the zonation of the tibial tubercle where the insertion of the patellar tendon is located. Then, 59 patients (23 males and 36 females) with a mean age 59.6 years (range 43-77 years), for a total of 69 knees (32 right and 37 left), who underwent routine knee surgery were observed and verified. According to the position of the patellar tendon insertion, TT-HTO was designed. Fifteen tibial sawbones were divided equally into three groups: TT-HTO; biplanar-DTO; and uniplanar-DTO. The total area of the osteotomy surface was compared using the graph paper method. The wedge volume at wedge heights of 10 mm was compared among osteotomy types using the plasticine Archimedes principle. One-way repeated-measures analysis of variance was used to compare the total area of the osteotomy surface and the wedge volume.

RESULTS

The osteotomy line of TT-HTO passes through the boundary point of zones B and C of the tibial tubercle to fully protect the insertion point of the patellar tendon. The total area of the osteotomy surface in TT-HTO and biplanar-DTO was significantly larger than that in uniplanar-DTO (P < 0.05). The wedge volume in uniplanar-DTO was significantly smaller than that in TT-HTO and biplanar-DTO (P < 0.05). No significant differences in the osteotomy surface and the wedge volume were identified between TT-HTO and biplanar-DTO.

CONCLUSION

TT-HTO can protect the patellar tendon insertion and avoid postoperative patella infera. The osteotomy surface is large and located in an area of cancellous bone, which ensures its good healing characteristics.

The catabolic-to-anabolic shift seen in the canine osteoarthritic cartilage treated with knee joint distraction occurs after the distraction period

Background

Methods

Results

Conclusion

The Translational Potential of this Article

Clinical monitoring in osteoarthritis: Biomarkers

OBJECTIVE

The purpose of this overview of osteoarthritis (OA) biomarkers is to provide the non-specialist with a toolbox, based on experience acquired by biomarker researchers over many years, to understand biomarkers in general and their use in the OA field.

METHODS

We provide an update on this subject since the OARSI Primer on osteoarthritis (OA) nearly a decade ago.

RESULTS

Since the last update, the importance of molecular biomarkers has been increasingly recognized in the field, but no OA-related biomarkers have been adopted for routine use in clinical practice. The current lack of chondroprotective treatments for OA impairs the assessment, validation and qualification of the potential role of biomarkers as tools for monitoring disease status and patient responses to treatment of OA. Yet there is no lack of an evolving compendium of OA-related biomarkers, ever more fit-for-purpose, that could currently facilitate drug development for OA. We provide an abbreviated update and overview of specific soluble OA-related biomarkers for this new OARSI Primer on OA with OA-relevant examples encompassing the concepts of biomarker nomenclature, qualification, interpretation, measurement, reporting requirements, application to research, drug discovery and clinical care, and future needs for biomarker advancement.

CONCLUSION

Appropriate biomarkers should play a role at all stages of OA diagnosis, prognosis, drug development, and treatment. The future of OA biomarker research and development holds great promise as its foundation is increasingly robust.

Subchondral bone changes after joint distraction treatment for end stage knee osteoarthritis

OBJECTIVE

Increased subchondral cortical bone plate thickness and trabecular bone density are characteristic of knee osteoarthritis (OA). Knee joint distraction (KJD) is a joint-preserving knee OA treatment where the joint is temporarily unloaded. It has previously shown clinical improvement and cartilage regeneration, indicating reversal of OA-related changes. The purpose of this research was to explore 3D subchondral bone changes after KJD treatment using CT imaging.

DESIGN

Twenty patients were treated with KJD and included to undergo knee CT imaging before, one, and two years after treatment. Tibia and femur segmentation and registration to canonical surfaces were performed semi-automatically. Cortical bone thickness and trabecular bone density were determined using an automated algorithm. Statistical parametric mapping (SPM) with two-tailed F-tests was used to analyze whole-joint changes.

RESULTS

Data was available of 16 patients. Subchondral cortical bone plate thickness and trabecular bone density were higher in the weight-bearing region of the most affected compartment (MAC; mostly medial). Especially the MAC showed a decrease in thickness and density in the first year after treatment, which was sustained towards the second year.

CONCLUSIONS

KJD treatment results in bone changes that include thinning of the subchondral cortical bone plate and decrease of subchondral trabecular bone density in the first two years after treatment, potentially indicating a partial normalization of subchondral bone.

Clinical and cost-effectiveness of Knee Arthroplasty versus Joint Distraction for Osteoarthritis (KARDS): protocol for a multicentre, phase III, randomised control trial

INTRODUCTION

Knee replacement (KR) is a clinically proven procedure typically offered to patients with severe knee osteoarthritis (OA) to relieve pain and improve quality of life. However, artificial joints fail over time, requiring revision associated with higher mortality and inferior outcomes. With more young people presenting with knee OA and increasing life expectancy, there is an unmet need to postpone time to first KR. Knee joint distraction (KJD), the practice of using external fixators to open up knee joint space, is proposed as potentially effective to preserve the joint following initial studies in the Netherlands, however, has not been researched within an NHS setting. The KARDS trial will investigate whether KJD is non-inferior to KR in terms of patient-reported postoperative pain 12 months post-surgery.

METHODS AND ANALYSIS

KARDS is a phase III, multicentre, pragmatic, open-label, individually randomised controlled non-inferiority trial comparing KJD with KR in patients with severe knee OA, employing a hybrid-expertise design, with internal pilot phase and process evaluation. 344 participants will be randomised (1:1) to KJD or KR. The primary outcome measure is the Knee Injury and Osteoarthritis Outcomes Score (KOOS) pain domain score at 12 months post-operation. Secondary outcome measures include patient-reported overall KOOS, Pain Visual Analogue Scale and Oxford Knee Scores, knee function assessments, joint space width, complications and further interventions over 24 months post-operation. Per patient cost difference between KR and KJD and cost per quality-adjusted life year (QALY) gained over 24 months will be estimated within trial, and incremental cost per QALY gained over 20 years by KJD relative to KR predicted using decision analytic modelling.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Research Ethics Committee (REC) and Health Research Authority (HRA). Trial results will be disseminated at clinical conferences, through relevant patient groups and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN14879004; recruitment opened April 2021.

Joint distraction for osteoarthritis: clinical evidence and molecular mechanisms

Joint distraction, the prolonged mechanical separation of the bones at a joint, has emerged as a joint-preserving treatment for end-stage osteoarthritis, with the gradually growing promise of implementation in regular clinical practice. Joint distraction of the knee has been most extensively studied, with these studies showing prolonged symptomatic improvement in combination with repair of cartilage tissue in degenerated knee joints, supporting the concept that cartilage repair can translate into real clinical benefit. The reversal of tissue degeneration observed with joint distraction could be the result of one or a combination of various proposed mechanisms, including partial unloading, synovial fluid pressure oscillation, mechanical and biochemical changes in subchondral bone, adhesion and chondrogenic commitment of joint-derived mesenchymal stem cells or a change in the molecular milieu of the joint. The overall picture that emerges from the combined evidence is relevant for future research and treatment-related improvements of joint distraction and for translation of the insights gained about tissue repair to other joint-preserving techniques. It remains to be elucidated whether optimizing the biomechanical conditions during joint distraction can actually cure osteoarthritis rather than only providing temporary symptomatic relief, but even temporary relief might be relevant for society and patients, as it will delay joint replacement with a prosthesis at an early age and thereby avert revision surgery later in life. Most importantly, improved insights into the underlying mechanisms of joint repair might provide new leads for more targeted treatment options.

Enhanced Extracellular Matrix Breakdown Characterizes the Early Distraction Phase of Canine Knee Joint Distraction

OBJECTIVE

Joint distraction triggers intrinsic cartilage repair in animal models of osteoarthritis (OA), corroborating observations in human OA patients treated with joint distraction. The present study explores the still largely elusive mechanism initiating this repair process.

DESIGN

Unilateral OA was induced in the knee joint of 8 dogs using the groove model; the contralateral joint served as a control. After 10 weeks, 4 animals received joint distraction, the other 4 serving as OA controls. Halfway the distraction period (after 4 weeks of a standard 8-week distraction treatment), all animals were euthanized, and joint tissues were collected. A targeted quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis was performed of commonly involved processes including matrix catabolism/anabolism, inflammation, and known signaling pathways in OA. In addition, cartilage changes were determined on tissue sections using the canine OARSI (Osteoarthritis Research Society International) histopathology score and collagen type II (COL2A1) immunostaining.

RESULTS

Midway distraction, the distracted OA joint showed an upregulation of proteolytic genes, for example, ADAMTS5, MMP9, MMP13, compared to OA alone and the healthy joints, which correlated with an increased OARSI score. Additionally, genes of the transforming growth factor (TGF)-β and Notch pathway, and markers associated with progenitor cells were increased.

CONCLUSIONS

Joint distraction initiates both catabolic and anabolic transcriptional responses. The enhanced turnover, and thereby renewal of the matrix, could be the key to the cartilage repair observed in the months after joint distraction.

Role of joint distraction in osteoarthritis of the knee: Basic science, principles and outcomes

The burden of knee osteoarthritis (OA) is increasing worldwide. Advanced tibiofemoral joint OA in young patients is particularly a problem with inferior results seen with total knee arthroplasty in this patient population. Knee joint distraction (KJD) has been evaluated recently as a joint preserving procedure for young patients with advanced tibiofemoral osteoarthritis, to delay the need for a primary total knee arthroplasty (TKA). This will decrease the risk for revision TKA later in life. KJD temporarily unloads the knee joint and keeps the tibia and femur separated over a course of 6 weeks. Outcomes of KJD appear promising. Through this article, the authors hope to share from their collective experience as well as the available literature on the basic science, principles of surgery and outcomes of KJD.

Knee Joint Distraction as Treatment for Osteoarthritis Results in Clinical and Structural Benefit: A Systematic Review and Meta-Analysis of the Limited Number of Studies and Patients Available

OBJECTIVE

Knee joint distraction (KJD) is a joint-preserving osteoarthritis treatment that may postpone a total knee arthroplasty (TKA) in younger patients. This systematic review and meta-analysis evaluates short- and long-term clinical benefit and tissue structure changes after KJD.

DESIGN

MEDLINE, EMBASE, and Web of Science were searched for eligible clinical studies evaluating at least one of the primary parameters: WOMAC, VAS-pain, KOOS, EQ5D, radiographic joint space width or MRI cartilage thickness after KJD. Random effects models were applied on all outcome parameters and outcomes were compared with control groups found in the included studies.

RESULTS

Eleven articles reporting on 7 different KJD cohorts with in total 127 patients and 5 control groups with multiple follow-up moments were included, of which 2 were randomized controlled trials. Significant improvements in all primary parameters were found and benefit lasted up to at least 9 years. Overall, outcomes were comparable with control groups, including high tibial osteotomy, although TKA showed better clinical response.

CONCLUSIONS

Current, still limited, evidence shows KJD causes clear benefit in clinical and structural parameters, both short- and long-term. Longer follow-up with more patients is necessary, to validate outcome and to potentially improve patient selection for this intensive treatment. Thus far, for younger knee osteoarthritis patients, KJD may be an option to consider.

Performance of knee image digital analysis of radiographs of patients with end-stage knee osteoarthritis

OBJECTIVE

Knee Image Digital Analysis (KIDA) is standardized radiographic analysis software for measuring osteoarthritis (OA) characteristics. It was validated in mild OA, but used for severe OA as well. The current goal was to evaluate the performance of KIDA in severe OA.

DESIGN

Of 103 patients, standardized radiographs were performed before and one and 2 years after treatment for severe OA. All radiographs were evaluated on subchondral bone density, joint space width (JSW), osteophytes, eminence height, and joint angle, twice within years by the same observer. Part of the radiographs were randomly selected for reevaluation twice within 1 month and evaluation by another observer. The intraclass correlation coefficient (ICC), smallest detectable difference (SDD) and coefficient of variation (CV) were calculated; the SDD and CV were compared to those in mild OA. The relation of severity with KIDA parameters and with observer differences was calculated with linear regression.

RESULTS

Intra-observer ICCs were higher in the 98 severe radiographs reanalyzed within 1 month (all >0.8) than the 293 reanalyzed within years (all >0.5; most >0.8) and than inter-observer ICCs (all >0.7). SDDs and CVs were smaller when reanalyzed within a month and comparable to those in mild OA. Some parameters showed bias between readings. Severity showed significant relation with osteophytes and JSW parameters, and with the observer variation in these parameters (all P < 0.04).

CONCLUSIONS

KIDA is a well-performing tool also for severe OA. In order to decrease variability and SDDs, images should be analyzed in a limited time frame and randomized order.

Comparison between 2D radiographic weight-bearing joint space width and 3D MRI non-weight-bearing cartilage thickness measures in the knee using non-weight-bearing 2D and 3D CT as an intermediary

Background:

In knee osteoarthritis, radiographic joint space width (JSW) is frequently used as a surrogate marker for cartilage thickness; however, longitudinal changes in radiographic JSW have shown poor correlations with those of magnetic resonance imaging (MRI) cartilage thickness. There are fundamental differences between the techniques: radiographic JSW represents two-dimensional (2D), weight-bearing, bone-to-bone distance, while on MRI three-dimensional (3D) non-weight-bearing cartilage thickness is measured. In this exploratory study, computed tomography (CT) was included as a third technique, as it can measure bone-to-bone under non-weight-bearing conditions. The objective was to use CT to compare the impact of weight-bearing versus non-weight-bearing, as well as bone-to-bone JSW versus actual cartilage thickness, in the knee.

Methods:

Osteoarthritis patients (n = 20) who were treated with knee joint distraction were included. Weight-bearing radiographs, non-weight-bearing MRIs and CTs were acquired before and 2 years after treatment. The mean radiographic JSW and cartilage thickness of the most affected compartment were measured. From CT, the 3D median JSW was calculated and a 2D projectional image was rendered, positioned similarly and measured identically to the radiograph. Pearson correlations between the techniques were derived, both cross-sectionally and longitudinally.

Results:

Fourteen patients could be analyzed. Cross-sectionally, all comparisons showed moderate to strong significant correlations (R = 0.43–0.81; all p < 0.05). Longitudinal changes over time were small; only the correlations between 2D CT and 3D CT (R = 0.65; p = 0.01) and 3D CT and MRI (R = 0.62; p = 0.02) were statistically significant.

Conclusion:

The poor correlation between changes in radiographic JSW and MRI cartilage thickness appears primarily to result from the difference in weight-bearing, and less so from measuring bone-to-bone distance versus cartilage thickness.

Knee joint distraction results in MRI cartilage thickness increase up to ten years after treatment

Objectives

Knee joint distraction (KJD) has been shown to result in long-term clinical improvement and short-term cartilage restoration in young OA patients. The objective of the current study was to evaluate MRI cartilage thickness up to 10 years after KJD treatment, using a 3D surface-based approach.

Methods

Twenty end-stage knee OA patients were treated with KJD. MRI scans (1.5 T) were performed before and at 1, 2, 5, 7, and 10 years after treatment. Tibia and femur cartilage segmentation and registration to a canonical surface were performed semi-automatically. Statistical parametric mapping with linear mixed models was used to analyse whole-joint changes. The influence of baseline patient characteristics was analysed with statistical parametric mapping using linear regression. Relevant weight-bearing parts of the femur were selected to obtain the average cartilage thickness in the femur and tibia of the most- (MAC) and least-affected compartment. These compartmental changes over time were analysed using repeated measures ANOVA; missing data was imputed. In all cases, P <0.05 was considered statistically significant.

Results

One and 2 years post-treatment, cartilage in the MAC weight-bearing region was significantly thicker than pre-treatment, gradually thinning after 5 years, but still increased at 10 years post-treatment. Long-term results showed that areas in the least-affected compartment were significantly thicker than pre-treatment. Male sex and more severe OA at baseline somewhat predicted shorter-term benefit (P >0.05). Compartmental analyses showed significant short- and long-term thickness increase in the tibia and femur MAC (all P <0.05).

Conclusion

KJD results in significant short- and long-term cartilage regeneration, up to 10 years post-treatment.

Trial registration

Netherlands Trial Register, https://www.trialregister.nl, NL419.

Osteoarthritis year in review 2020: imaging

This narrative "Year in Review" highlights a selection of articles published between January 2019 and April 2020, to be presented at the OARSI World Congress 2020 within the field of osteoarthritis (OA) imaging. Articles were obtained from a PubMed search covering the above period, utilizing a variety of relevant search terms. We then selected original and review studies on OA-related imaging in humans, particularly those with direct clinical relevance, with a focus on the knee. Topics selected encompassed clinically relevant models of early OA, particularly imaging applications on cruciate ligament rupture, as these are of direct clinical interest and provide potential opportunity to evaluate preventive therapy. Further, imaging applications on structural modification of articular tissues in patients with established OA, by non-pharmacological, pharmacological and surgical interventions are summarized. Finally, novel deep learning approaches to imaging are reviewed, as these facilitate implementation and scaling of quantitative imaging application in clinical trials and clinical practice. Methodological or observational studies outside these key focus areas were not included. Studies focused on biology, biomechanics, biomarkers, genetics and epigenetics, and clinical studies that did not contain an imaging component are covered in other articles within the OARSI "Year in Review" series. In conclusion, exciting progress has been made in clinically validating human models of early OA, and the field of automated articular tissue segmentation. Most importantly though, it has been shown that structure modification of articular cartilage is possible, and future research should focus on the translation of these structural findings to clinical benefit.

An Increase in Medial Joint Space Width After Medial Open-Wedge High Tibial Osteotomy Is Associated With an Increase in the Postoperative Weight-Bearing Line Ratio Rather Than With Cartilage Regeneration: Comparative Analysis of Patients Who Underwent Second-Look Arthroscopic Assessment

PURPOSE

To investigate relevant factors influencing increases in medial joint space width (JSW) after medial open-wedge high tibial osteotomy (MOWHTO).

METHODS

Between January 2010 and December 2018, the electronic medical records of consecutive patients who underwent MOWHTO and subsequent second-look arthroscopic assessment at least 12 months after MOWHTO were retrospectively evaluated. The patients were classified into 2 groups according to changes in the medial JSW of the knee at the time of the second-look operation compared with that at baseline before the initial surgical procedure. Various radiographic parameters, arthroscopic findings, and clinical scores were compared between the groups, and regression analysis was performed to identify factors related to increases in medial JSW.

RESULTS

A total of 114 patients were analyzed. In a bivariate analysis, patients who experienced an increase in medial JSW showed a significantly higher postoperative weight-bearing line ratio (WBLR) (P = .008) and a greater proportion of severe preoperative cartilage lesions in the medial compartment of the knee compared with patients with a maintained or reduced medial JSW (P = .035). In terms of clinical scores, patients with an increased medial JSW showed relatively favorable clinical outcomes at the time of the second-look operation. Regression analysis indicated only postoperative WBLR as a relevant factor associated with an increase in medial JSW after MOWHTO (odds ratio, 1.057; P = .01). Additional analysis with patients reclassified according to the postoperative WBLR showed that as the postoperative WBLR increased, the medial JSW increased, without a significant change in the lateral JSW.

CONCLUSIONS

An increase in the medial JSW of the knee joint after MOWHTO appears to be associated with an increase in the postoperative WBLR, not with cartilage regeneration. Obtaining adequate correction so that the postoperative WBLR is within 60% to 70% would be desirable in terms of postoperative changes in the medial JSW, as well as clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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

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 (KJD_HTO) or HTO treatment. Patients indicated for total knee arthroplasty received KJD (KJD_TKA). 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, KJD_HTO 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. KJD_TKA (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.

Medial joint space width and convergence angle change with time after medial opening-wedge high tibial osteotomy

BACKGROUND

Although the medial joint space width (MJSW) is commonly used for radiographic evaluation of knee osteoarthritis, the changes in knee joint space width (JSW) during weight bearing after medial opening-wedge high tibial osteotomy (MOWHTO) remain unclear. This study aimed to depict how medial and lateral JSWs and convergence angles change gradually after MOWHTO.

METHODS

We retrospectively followed up 81 MOWHTO cases for over 45 months on average. Pre- and postoperative mechanical axes were recorded. The JSWs and convergence angles were measured preoperatively, immediately postoperatively, and 3-6, 9-12, and 21-24 months postoperatively. Patient-reported outcomes were measured using a visual analogue scale (VAS).

RESULTS

The mean mechanical femoral-tibial angle improved from 8.1° varus to 2.4° valgus. At the aforementioned times, the respective mean values of MJSW were 2.6, 3.5, 3.8, 4.0, and 4.2 mm; mean convergence angles were 4.8°, 2.9°, 2.2°, 2.1°, and 1.9°; and the mean VAS scores were 7.2, 7.8, 4.8, 1.4, and 1.3. The MJSW continued to increase significantly in the first year postoperatively and then plateaued for a minimum of 2 years follow up after MOWHTO. The convergence angle decreased significantly in the first 6 months postoperatively and was then maintained.

CONCLUSIONS

The MJSW, convergence angle, and VAS scores continued to improve through weight bearing during the first year after MOWHTO and were maintained for at least 2 years. Thus, JSW measurement may be an easy and representative way of radiographically monitoring the effect of MOWHTO.

Reduction of pin tract infections during external fixation using cadexomer iodine

PURPOSE

Knee joint distraction (KJD) is a joint-preserving treatment for younger osteoarthritis patients. KJD has shown positive results in regular care, but the external fixation frame often caused pin tract skin infections. Therefore, the use of cadexomer iodine was included in the wound care protocol. The goal of this cross-sectional study was to evaluate whether use of this ointment reduced the number of patients with infections during KJD treatment.

METHODS

Patients treated with KJD in regular care were included if they gave consent for use of their data and completed treatment with the newest distraction device before 2020. All patients followed a wound care protocol, which since March 2019 included using cadexomer iodine ointment. The number of patients experiencing pin tract infections was compared between patients who did (March 2019-December 2019) and did not (November 2017-March 2019) use the ointment.

RESULTS

Sixty-seven patients were included; 34 patients used cadexomer iodine and 33 patients did not. Patient who did not use cadexomer iodine experienced twice as many infections (64% vs 32%;p = 0.010). There was a significant difference in the number of patients with serious infections, requiring more antibiotics than the standard 7-day oral antibiotics (30% without vs 6% with cadexomer iodine; p = 0.009).

CONCLUSIONS

The use of cadexomer iodine ointment during KJD results in a significant reduction of the number of patients experiencing pin tract infections during treatment. Use of this ointment should be considered standard protocol during KJD treatment and could be of value in general external fixator usage as well.

Gene Expression Signatures of Synovial Fluid Multipotent Stromal Cells in Advanced Knee Osteoarthritis and Following Knee Joint Distraction

Osteoarthritis (OA) is the most common musculoskeletal disorder. Although joint replacement remains the standard of care for knee OA patients, knee joint distraction (KJD), which works by temporarily off-loading the joint for 6–8 weeks, is becoming a novel joint-sparing alternative for younger OA sufferers. The biological mechanisms behind KJD structural improvements remain poorly understood but likely involve joint-resident regenerative cells including multipotent stromal cells (MSCs). In this study, we hypothesized that KJD leads to beneficial cartilage-anabolic and anti-catabolic changes in joint-resident MSCs and investigated gene expression profiles of synovial fluid (SF) MSCs following KJD as compared with baseline. To obtain further insights into the effects of local biomechanics on MSCs present in late OA joints, SF MSC gene expression was studied in a separate OA arthroplasty cohort and compared with subchondral bone (SB) MSCs from medial (more loaded) and lateral (less loaded) femoral condyles from the same joints. In OA arthroplasty cohort (n = 12 patients), SF MSCs expressed lower levels of ossification- and hypotrophy-related genes [bone sialoprotein (IBSP), parathyroid hormone 1 receptor (PTH1R), and runt-related transcription factor 2 (RUNX2)] than did SB MSCs. Interestingly, SF MSCs expressed 5- to 50-fold higher levels of transcripts for classical extracellular matrix turnover molecules matrix metalloproteinase 1 (MMP1), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and tissue inhibitor of metalloproteinase-3 (TIMP3), all (p < 0.05) potentially indicating greater cartilage remodeling ability of OA SF MSCs, compared with SB MSCs. In KJD cohort (n = 9 patients), joint off-loading resulted in sustained, significant increase in SF MSC colonies’ sizes and densities and a notable transcript upregulation of key cartilage core protein aggrecan (ACAN) (weeks 3 and 6), as well as reduction in pro-inflammatory C–C motif chemokine ligand 2 (CCL2) expression (weeks 3 and 6). Additionally, early KJD changes (week 3) were marked by significant increases in MSC chondrogenic commitment markers gremlin 1 (GREM1) and growth differentiation factor 5 (GDF5). In combination, our results reveal distinct transcriptomes on joint-resident MSCs from different biomechanical environments and show that 6-week joint off-loading leads to transcriptional changes in SF MSCs that may be beneficial for cartilage regeneration. Biomechanical factors should be certainly considered in the development of novel MSC-based therapies for OA.

The molecular profile of synovial fluid changes upon joint distraction and is associated with clinical response in knee osteoarthritis

OBJECTIVE

Surgical knee joint distraction (KJD) leads to clinical improvement in knee osteoarthritis (OA) and also apparent cartilage regeneration by magnetic resonance imaging. We investigated if alteration of the joint's mechanical environment during the 6 week period of KJD was associated with a molecular response in synovial fluid, and if any change was associated with clinical response.

METHOD

20 individuals undergoing KJD for symptomatic radiographic knee OA had SF sampled at baseline, midpoint and endpoint of distraction (6 weeks). SF supernatants were measured by immunoassay for 10 predefined mechanosensitive molecules identified in our previous pre-clinical studies. The composite Knee injury and OA Outcome Score-4 (KOOS₄) was collected at baseline, 3, 6 and 12 months.

RESULTS

13/20 (65%) were male with mean age 54°±°5yrs. All had Kellgren-Lawrence grade ≥2 knee OA. 6/10 analytes showed statistically significant change in SF over the 6 weeks distraction (activin A; TGFβ-1; MCP-1; IL-6; FGF-2; LTBP2), P < 0.05. Of these, all but activin A increased. Those achieving the minimum clinically important difference of 10 points for KOOS₄ over 6 months showed greater increases in FGF-2 and TGFβ-1 than non-responders. An increase in IL-8 during the 6 weeks of KJD was associated with significantly greater improvement in KOOS₄ over 12 months.

CONCLUSION

Detectable, significant molecular changes are observed in SF following KJD, that are remarkably consistent between individuals. Preliminary findings appear to suggest that increases in some molecules are associated with clinically meaningful responses. Joint distraction may provide a potential opportunity in the future to define regenerative biomarker(s) and identify pathways that drive intrinsic cartilage repair.

Knee joint distraction in regular care for treatment of knee osteoarthritis: A comparison with clinical trial data

Objectives

Knee joint distraction (KJD) has been evaluated as a joint-preserving treatment to postpone total knee arthroplasty in knee osteoarthritis patients in three clinical trials. Since 2014 the treatment is used in regular care in some hospitals, which might lead to a deviation from the original indication and decreased treatment outcome. In this study, baseline characteristics, complications and clinical benefit are compared between patients treated in regular care and in clinical trials.

Methods

In our hospital, 84 patients were treated in regular care for 6 weeks with KJD. Surgical details, complications, and range of motion were assessed from patient hospital charts. Patient-reported outcome measures were evaluated in regular care before and one year after treatment. Trial patients (n = 62) were treated and followed as described in literature.

Results

Patient characteristics were not significantly different between groups, except for distraction duration (regular care 45.3±4.3; clinical trials 48.1±8.1 days; p = 0.019). Pin tract infections were the most occurring complication (70% regular care; 66% clinical trials), but there was no significant difference in treatment complications between groups (p>0.1). The range of motion was recovered within a year after treatment for both groups. WOMAC questionnaires showed statistically and clinically significant improvement for both groups (both p<0.001 and >15 points in all subscales) and no significant differences between groups (all differences p>0.05). After one year, 70% of patients were responders (regular care 61%, trial 75%; p = 0.120). Neither regular care compared to clinical trial, nor any other characteristic could predict clinical response.

Conclusions

KJD as joint-preserving treatment in clinical practice, to postpone arthroplasty for end-stage knee osteoarthritis patient below the age of 65, results in an outcome similar to that thus far demonstrated in clinical trials. Longer follow-up in regular care is needed to test whether also long-term results remain beneficial and comparable to trial data.

The role of joint distraction in the treatment of knee osteoarthritis: a systematic review and quantitative analysis

Introduction

Knee osteoarthritis is a major cause of pain and disability for which joint distraction is a potential treatment to delay the need for knee arthroplasty. This systematic review aims to assess the short- and long-term clinical and structural outcomes following knee joint distraction (KJD).

Methods

MEDLINE, EMBASE, Scopus, and Web of Science databases were searched from the date of inception to 26th June 2019. Clinical studies investigating joint distraction for knee osteoarthritis with outcomes including ∆WOMAC index, ∆VAS pain score, and ∆joint space width were included. The review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) – CRD42018087032.

Results

Nine studies comprising a total of 507 patients were included. There were four randomized controlled trials (RCTs), five open prospective cohort studies, and one case series. Overall, there were significant improvements in WOMAC index, VAS pain score and joint space width following KJD, which persisted up to 9 years. KJD also demonstrated comparable clinical outcomes with high tibial osteotomy and total knee arthroplasty.

Conclusion

There is moderate quality evidence supporting the beneficial outcomes of joint distraction for knee osteoarthritis. Larger RCTs with longer follow-up (>1 year) are necessary to establish the true effect size of this procedure.