Authors' objectives: Osteoarthritis is the most common joint disease worldwide costing between 1% and 2.5% of gross domestic product in developed countries. Once a hip or knee develops end-stage disease, arthroplasty surgery is highly successful in most patients. Treatment options are limited for early disease, and patients may fall into a ‘treatment gap’, despite having severe symptoms. Many surgical procedures are used to treat early osteoarthritis of the hip and knee, but the clinical and cost-effectiveness of these techniques remains unclear. Use systematic review and evidence synthesis to determine the clinical effectiveness of current surgical interventions for early hip and knee osteoarthritis. Estimate the cost-effectiveness of these procedures using decision model analytic modelling. Create clinical treatment guidance and identify areas where new clinical research is required. Osteoarthritis (OA) is the most common joint disease worldwide costing between 1.0% and 2.5% of gross domestic product in developed countries. OA is a joint wide condition characterised by damage to the articular surfaces of the joint, bone sclerosis and cysts, stiffness of the soft tissues around the knee, synovitis and intermittent joint effusions. Many patients with structural hip and knee OA have no or very mild symptoms from their joint. However, there are a group of patients with early or late OA structural changes who develop more pronounced hip or knee pain and loss of function, described as clinical OA, which includes a broad set of symptoms, characterised by pain and stiffness in the joint that produces a reduction in function and ultimately in quality of life (QoL). All patients who present with clinical OA should undergo initial treatment following the National Institute for Health and Care Excellence (NICE) clinical guideline CG226, with good education on their condition and treatment options; therapeutic exercise; and weight loss if appropriate. Second-line additional treatments can be introduced, such as topical or oral non-steroidal anti-inflammatory drugs (NSAIDs) and third-line adjunctive measures can then be considered, including intra-articular (IA) injections, manual therapy and bracing. However, not all patients respond to non-operative treatment and some develop persistent severe symptoms. For patients in this group who have end-stage (late) structural hip or knee OA, joint replacement (arthroplasty) is a highly successful treatment option. However, there are patients with early structural disease with symptoms as severe as for end-stage disease, that are also unresponsive to non-operative treatment. Joint replacement is typically not offered to patients with earlier structural disease as it is believed to be less effective and these patients may fall into a ‘treatment gap’. Many surgical procedures have been adopted to fill this gap in treatment for early hip or knee OA, but often with limited success and at significant expense. It remains unclear how and when these techniques are best employed, and a more evidence-based approach is required. Use systematic review and evidence synthesis to determine the clinical effectiveness of current surgical interventions for early hip and knee OA. Estimate the cost-effectiveness of these procedures using decision-analytic modelling. Create clinical treatment guidance and identify areas where new clinical research is required

Authors' results and conclusions: The systematic review identified 61,098 studies, and our evidence synthesis identified a number of surgical techniques that have been used to treat early hip and knee osteoarthritis. However, we found very little meaningful evidence of the clinical efficacy for the majority of the surgical procedures. We only found seven randomised controlled trials and three non-randomised studies that compared a surgical technique to non-operative treatment. There were two surgical treatments that had limited but supportive evidence. Femoro-acetabular impingement is an early stage of hip osteoarthritis, and there is some evidence that arthroscopic chondroplasty provides patients with clinical relief of symptoms, above that seen with non-operative measures. In the knee, weaker evidence suggests arthroscopic debridement of osteoarthritic articular cartilage fragments may be of benefit, above non-operative measures. Health economic analysis suggests that both procedures may be cost-effective, but the evidence is again of low quality. There is a significant gap in the evidence base supporting surgical interventions in early hip and knee osteoarthritis. Limited evidence suggests that arthroscopic chondroplasty procedures may be effective in treating hip femoro-acetabular impingement and early knee osteoarthritis. A small number of randomised studies are in progress, but these studies do not encompass all procedures that are in use. Overall, our study identified a significant gap in the evidence base to support surgical interventions in early hip and knee OA, although many surgical techniques are used to treat this group of patients. There were only two surgical techniques where we could demonstrate evidence to suggest that they are effective treatments, one in hip and one in knee patients. In the hip there is evidence of the efficacy of osteochondroplasty to treat hip FAI compared to non-operative treatment. There appears to be a modest additional benefit to surgery improving pain and function, leading to a potential cost-effectiveness benefit over a 5-year window. In similar fashion there is limited evidence suggesting that arthroscopic chondroplasty may be effective in treating early knee OA. But this is underpinned with clinical outcome data of low certainty, from very few studies. In both cases, results must be treated with some caution as both clinical and health economic results have a low-level of evidence certainty. A small number of randomised studies are in progress, including assessments of HTO in the knee and labral tear repair in the hip. The results of these studies will be useful additions to the evidence base, but do not encompass all procedures that are in use. A particular note must be made of the lack of studies relating to biological reconstruction surgery, suggesting that surgical techniques that are successful in treating isolated cartilage defects in the hip and knee joint, have not been translated into treatment of early OA. Similarly joint replacement, which is very established as a frontline treatment for late-stage hip and knee OA, has not been assessed as a treatment for early knee OA. This probably reflects prognostic cohort studies suggesting that a diagnosis of early hip and knee OA has a negative effect on clinical outcome for patients. Our key recommendation is that more high-quality comparative randomised studies are required to establish if the surgical interventions that are currently used are effective when compared to non-operative treatments. In developing studies, methodology must include agreed widely used definitions of early OA and the non-operative treatments used to build consistency across studies.

Authors' methods: The programme of work consisted of systematic review, evidence synthesis and health economic modelling for surgical treatments used for early hip and knee osteoarthritis. We divided treatments into four groups: (1) non-regenerative procedures, (2) regenerative procedures, (3) load-modifying procedures and (4) arthroplasty procedures. They were compared with non-surgical treatment following National Institute for Health and Care Excellence guidance. We used outcome measures that satisfied the Outcome Measures in Rheumatoid Arthritis Clinical Trials and Osteoarthritis Research Society International core outcome set for hip and knee osteoarthritis. Decision-analytic models were developed to assess the cost-effectiveness of treatment alternatives expressed as cost per quality-adjusted life-year gained. The original updated searches completed in January 2021, with a further search for randomised controlled studies completed in January 2025. The programme of work consisted of systematic review, evidence synthesis and health economic modelling for surgical treatments used for early hip and knee OA. Definition of early osteoarthritis We have defined early OA as (1) the presence of typical OA symptoms and (2) radiological evidence of structural early OA and (3) the absence of widespread disease. Diagnostic criteria for early structural hip or knee OA were one or more of; (1) loss of joint space on a weight-bearing radiograph (excluding bone-on-bone change), (2) partial-thickness cartilage loss, cartilage delamination or focal full-thickness cartilage on magnetic resonance imaging, (3) cartilage changes affecting the joint seen at arthroscopy or open surgery. Painful hip dysplasia and femoro-acetabular impingement (FAI) of the hip were included, as they represent an initial phase of the hip OA.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR127398

Year Published: 2026

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/TNFD7352

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/TNFD7352

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk