Search protocol and registration
This systematic review used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), a technique that addresses the eligibility, data sources, selection of studies, data extraction, and data analysis as a reporting guideline [15]. This review was registered on PROSPERO, with registration number, CRD: CRD42018096524.
Data sources
A search of literature for published and unpublished studies was conducted to MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), AMED, Scopus, Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment (HTA) database, and the National Health Service Economic Evaluation Database (NHS EED) in the last 2 decades. The search terms used were hip, replace*, “total hip replacement’’, arthroplasty, “total hip arthroplasty’’, “therapeutic exercise’’, training, “functional training’’, “home physical training’’, “joint mobilization’’, exercise, physical therapist, therap*, treatment, medicine, muscle*, quadriceps*, strength, function, kinesiotherap*, rehabilitation, physiotherapy, “exercise therapy’’, “physical therapy’’, effectiveness, “clinical effectiveness’’, cost, value, money, expenditure, QALY, HRQoL, “healthcare costs’’, economics, “cost-effectiveness analysis’’, “cost-utility analysis’’, and “cost–benefit analysis’’. These search terms were combined using conjunctions such as “AND’’ and “OR’’.
Search strategy
The Population, Intervention, Comparison, Outcome (PICO) framework was utilized in the development of the search strategy with search terms and limits relating to population of interest and intervention. The inclusion criteria were studies that: included patients (mean age ≥ 18 years) following THR for hip OA; assessed the clinical or cost-effectiveness of different forms of physiotherapy compared to other forms of physiotherapy or no intervention; reporting results of randomized-controlled and retrospective/prospective trials. In this review, physiotherapy interventions covered a range of techniques including massage, passive stretching, functional rehabilitation, interdisciplinary rehabilitation, exercise, physical training, acupuncture, spinal manipulation, advice, yoga, cognitive behavioural therapy, and martial arts. The economic evaluation (cost-effectiveness analysis, cost–benefit analysis, and cost–utility analysis) carried out alongside randomized-controlled trials and retrospective cohort study were included.
The outcomes of interest in this review included: pain, function, muscle strength, clinical and motor performance, activities of daily living, and health-related quality of life. To be included for the economic evaluation, studies had to relate the costs of the interventions to the effects of the interventions. Systematic reviews, narrative literature reviews, studies of non-English language, and conference papers were excluded. Further exclusion criteria were abstract unavailable, studies not yet fully completed, and studies carried out with THR patients mean aged < 18 years.
Duplicates were removed electronically and manually. Two independent researchers (TG and FF) were involved in screening the title and abstract of each study. Full-text articles were obtained and were excluded if they did not meet the inclusion criteria. Any disagreement in study selection was resolved through discussion and consultation with other members of the team (GY and JMW) where necessary.
Data extraction and risk of bias assessment
One of the researchers extracted data (TG) and the three members of the team cross-checked the extracted data (FF, GY, and JMW). The following data were extracted: author and date of the study, the location/country, type of participant, and the number of participants involved in the study. The mean age, percentage of male and female participants who received the interventions and the control arm, and the type and the duration of the physiotherapy interventions were also extracted from each study. Furthermore, data regarding outcome measures, including the primary and secondary health outcomes, resource use and cost, and the cost-effectiveness ratio (ICER) were extracted.
Risk of bias for studies that met the inclusion criteria for the clinical effectiveness was assessed using the criteria of the Cochrane Risk of Bias Tool [16]. The Cochrane Collaboration’s tool aims to make the process clearer and more accurate, and it covers six domains of bias such as selection bias, performance bias, detection bias, attrition bias, reporting bias, and other bias. Studies were considered high risk of bias when one or more of the key domains had unclear or high risk of bias [16].
The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement was also used as a reporting guideline for the included cost-effectiveness studies [17]. Twenty-four items were addressed in six categories, which include title and abstract, introduction, methods, results, discussion, and others. Cost-effectiveness studies were rated positive (√) if they reported in full, and negative (x) if they did not fulfil the listed criteria in the CHEERS statement. For those studies that have partial or inconclusive information, they were labelled as partial (P). A total score of 1 was assigned if they fulfilled the requirement of reporting for that Item completely, 0 for not reporting and 0.5 for partial reporting. The maximum score for an article that reported completely all information was 24.
Data analysis
A descriptive synthesis and meta-analysis of the extracted data is presented. This study considered a weighting procedure for the clinical effectiveness of physiotherapy interventions as well as its cost-effectiveness of the included studies only when the procedure for combining data from multiple studies was satisfied. The continuous outcomes measures were expressed as a weighted mean difference with 95% confidence intervals. To summarise the findings across the studies, a statistical significance of p < 0.05 was set. Due to the statistical evidence of heterogeneity across the studies, a random-effects model was chosen [15].