Clinical Research Directory

Development of an Outcome Score for Patients With Knee Osteoarthritis and Knee Joint Endoprosthesis Using an App

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) is one of the most frequent orthopedic procedures. Over 50% of patients report higher expectations than their surgeons, and 10-50% remain dissatisfied postoperatively. Persistent pain, functional limitations, and unmet expectations are key drivers. Identifying risks pre- and early postoperatively is essential, alongside empowering patients through self-management. Existing scoring systems integrate PROMs, demographics, and sometimes imaging but within limited timeframes. They rarely capture functional deficits or long-term trajectories. Digital health solutions for TKA (pre-)rehabilitation exist, yet most focus on physiotherapy and education rather than predictive outcome modeling. To address this gap, the study team has developed a novel mobile application that enables the documentation and analysis of movement data up to 10 years before surgery and throughout long-term follow-up. These data are combined with PROMs and functional test results, providing a unique basis for outcome prediction and risk stratification in TKA/THA. Primary Objective The aim of this pilot study is to develop a composite outcome score for TKA/THA patients. This score will integrate demographic variables, PROMs, and objective functional measures (knee joint angles, gait parameters, walk tests) to identify risk factors for dissatisfaction and support predictive modeling. A machine learning algorithm will be trained using the collected dataset to predict patient satisfaction after TKA/THA. Endpoints Primary endpoint: Overall patient satisfaction Secondary endpoints: Age, height, weight, step count, step length, gait asymmetry, gait speed, double support phase, knee joint ROM, walk test, KOOS, SF-36, EQ5d, satisfaction with the app, and satisfaction with app use. Study Population App-Group: Inclusion criteria are patients ≥18 years before or after TKA/THA. Exclusion criteria include missing consent, ineligible diagnosis, lack of smartphone, age \<18 years, or insufficient German language skills (as no English version of the app is currently available). Planned enrollment: 450 patients. Non-App-Group: Inclusion criteria are patients ≥18 years before or after TKA/THA. Exclusion criteria include missing consent, ineligible diagnosis, age \<18 years, or insufficient German language skills (as no English version of the app is currently available). Planned enrollment: 450 patients. Healthy-group: Inclusion criteria are healthy proband ≥18 years with no lower limb conditions. The overall procedure is identical to that of the AppGroup. Exclusion criteria include missing consent, ineligible diagnosis, no smartphone, age \<18 years, or insufficient German language skills (as no English version of the app is currently available). Planned enrollment: 450 patients. Methods Design: Single-center, prospective pilot study. The app collects patient-authorized movement data already stored on smartphones as well as future data. Participants choose which data to share. In addition, they are prompted to complete gait tests and knee function tests. PROMs (KOOS, SF-36, satisfaction) are administered at regular intervals.

OXINIUM◊ DH Total Hip Arthroplasty Pivotal Study

The purpose of this study is to monitor safety of the participants implanted with the OXINIUM◊ DH Hip System up to 10-years post-implantation

General vs Spinal in Total Joint Arthroplasty (TJA)

The purpose of this research is to compare post-operative outcomes from patients undergoing TJA. The study team wants to learn about outcomes like length of hospital stay, post-operative pain scores, post-operative nausea, deep and superficial surgical site infection, periprosthetic fracture (a broken bone that occurs around an orthopaedic implant), implant dislocation, readmission rates, and revision rates.

Three Variants of the PENG Block With and Without Perineural Adjuvants in Older Adults

This study will compare three versions of the Pericapsular Nerve Group (PENG) block in adults aged 65 years and older who are undergoing hip surgery. The PENG block is a regional anesthesia technique used to reduce pain around the hip joint and may improve early recovery after surgery. All patients in the study will receive the PENG block using 20 mL of 0.2% ropivacaine. They will then be randomly assigned to one of three groups: Group 1: PENG block using ropivacaine only (no additional medications). Group 2: PENG block using ropivacaine with 4 mg of dexamethasone injected near the nerves. Group 3: PENG block using ropivacaine with 25 micrograms of dexmedetomidine injected near the nerves. Dexamethasone and dexmedetomidine are medications that may increase the duration and quality of regional anesthesia. It is not known whether adding one of these medications provides longer-lasting or better pain relief compared to using ropivacaine alone. The main purpose of this study is to determine whether the addition of dexamethasone or dexmedetomidine improves the effectiveness of the PENG block in relieving pain after hip surgery. The study will evaluate pain levels, opioid consumption, time to first rescue pain medication, need for additional analgesia, and recovery outcomes. Safety, side effects, and any block-related complications will also be monitored. The investigators hypothesize that adding either perineural dexamethasone or dexmedetomidine will result in longer and more effective pain relief compared with the standard PENG block without an adjuvant. This research may help identify the most effective form of the PENG block for older adults undergoing hip surgery and contribute to improved pain management, reduced opioid use, and better postoperative recovery.

PENG Block Variants With Dexamethasone and Dexmedetomidine in Older Adults

This study will compare three different versions of the Pericapsular Nerve Group (PENG) block in adults aged 65 years and older who are undergoing surgery for hip conditions. The PENG block is a regional anesthesia technique that can reduce pain after surgery and decrease the need for strong opioid pain medications. All patients in the study will receive the PENG block with 20 mL of 0.2% ropivacaine, but they will be divided into three groups based on the additional medications used: Group 1: PENG block with ropivacaine plus 4 mg of dexamethasone given intravenously. Group 2: PENG block with ropivacaine plus 25 micrograms of dexmedetomidine given near the nerves and 4 mg of dexamethasone given intravenously. Group 3: PENG block with ropivacaine plus 25 micrograms of dexmedetomidine and 4 mg of dexamethasone given near the nerves. Both dexmedetomidine and dexamethasone are medications that may improve the strength and duration of nerve blocks. The main goal of this study is to determine which combination provides the best pain control after hip surgery, reduces the need for opioid medications, and improves patient comfort and recovery. We also aim to evaluate the safety and side-effects of each technique. We hypothesize that adding both dexmedetomidine and dexamethasone near the nerves will provide the longest and most effective pain relief when compared to intravenous administration alone. This trial may help identify the most effective PENG block formula for older adults undergoing hip surgery and could improve pain management, decrease complications related to opioids, and support faster recovery.

What Matters to Patients With Severe Hip or Knee Osteoarthritis?

This clinical trial aims to investigate if shared decision-making, and the use of an in-consultation patient decision aid (PtDA), increases the decisional quality and therefore treatment satisfaction and outcome of patients with severe hip or knee osteoarthritis. Finally, an evaluation will be conducted on patient-reported outcomes on pain, physical function, quality of life (QoL), and patient satisfaction, up to one year after surgery.

PENG Block vs Suprainguinal FICB vs Lumbar ESPB for Analgesia After Hip Surgery

This randomized, double-blinded, controlled clinical trial compares three motor-sparing regional anesthesia techniques used for postoperative analgesia in patients undergoing hip arthroplasty: the Pericapsular Nerve Group (PENG) block, the suprainguinal Fascia Iliaca Compartment Block (S-FICB), and the Lumbar Erector Spinae Plane Block (L-ESPB). Although all three techniques are widely used in modern hip surgery, their relative analgesic efficacy, opioid-sparing potential, and impact on early functional recovery have not been directly compared in a single study. The primary objective is to determine which block provides the most effective postoperative analgesia while preserving motor function and facilitating early mobilization. Secondary objectives include comparisons of opioid consumption, pain scores at rest and during movement, time to first rescue analgesia, block-related adverse events, quadriceps strength, incidence of postoperative nausea and vomiting, and early functional outcomes. This study aims to identify the optimal motor-sparing regional anesthesia strategy for older adults undergoing hip arthroplasty.

SII Levels Following PENG Block in Hip Arthroplasty

This randomized controlled trial evaluates the effect of ultrasound-guided Pericapsular Nerve Group (PENG) block on the Systemic Immune-Inflammation Index (SII) in elderly patients undergoing total hip arthroplasty under spinal anesthesia. SII, calculated as platelet × neutrophil / lymphocyte count, is used as a composite marker of perioperative inflammatory and immune response. The study investigates whether PENG block attenuates the systemic inflammatory reaction to surgical trauma compared to sham block.

PENG Block and Delirium After Hip Arthroplasty

Postoperative delirium is a common and serious complication in older adults undergoing total hip arthroplasty, associated with prolonged hospitalization, increased morbidity, delayed rehabilitation, and long-term cognitive decline. Modifiable perioperative risk factors include uncontrolled postoperative pain, opioid consumption, impaired early mobilization, and systemic inflammatory response. The Pericapsular Nerve Group (PENG) block is a regional anesthesia technique targeting the sensory innervation of the anterior hip capsule and may provide effective analgesia while preserving motor function. Improved pain control and opioid reduction may decrease the incidence of postoperative delirium. This prospective, randomized, parallel-group controlled trial aims to evaluate whether the addition of ultrasound-guided PENG block to spinal anesthesia reduces the incidence of postoperative delirium within 72 hours after primary total hip arthroplasty in patients aged 65 years or older. Delirium will be assessed using the Confusion Assessment Method (CAM) by blinded outcome assessors. Secondary outcomes include postoperative opioid consumption, pain intensity (NRS), time to first rescue opioid, postoperative nausea and vomiting, time to mobilization, block-related adverse events, and perioperative inflammatory indices (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio). The study will enroll 144 patients randomized 1:1 to spinal anesthesia alone or spinal anesthesia plus PENG block.

PENG Block With Dexmedetomidine in Older Adults

Pain after hip surgery is a common problem in older adults and may delay early mobilization, increase the need for opioid pain medications, and contribute to complications such as delirium, nausea, or prolonged hospital stay. Regional anesthesia techniques are increasingly used to improve pain control while reducing the use of systemic opioids. The pericapsular nerve group (PENG) block is a modern ultrasound-guided regional anesthesia technique designed to provide effective pain relief after hip surgery while preserving muscle strength. It allows patients to begin mobilization earlier and may reduce the risk of postoperative complications, which is particularly important in older adults. Ropivacaine is a commonly used local anesthetic for nerve blocks. Dexmedetomidine is a medication that, when added in small doses to local anesthetics, may prolong pain relief and improve the quality of nerve blocks without significantly increasing side effects. However, the benefits and safety of adding dexmedetomidine to the PENG block in older adults have not been sufficiently studied. The aim of this randomized controlled clinical study is to compare the effectiveness and safety of two PENG block techniques in older adults undergoing hip surgery. Participants will be randomly assigned to one of two groups. One group will receive a PENG block with 20 mL of 0.2% ropivacaine. The second group will receive a PENG block with 20 mL of 0.2% ropivacaine combined with 25 micrograms of dexmedetomidine. The study hypothesis is that the addition of dexmedetomidine to ropivacaine in the PENG block will provide longer-lasting and more effective postoperative pain relief compared with ropivacaine alone, without increasing adverse effects. Outcomes assessed in the study will include postoperative pain intensity, need for additional pain medications, time to first mobilization, and the occurrence of side effects such as low blood pressure, slow heart rate, excessive sedation, or delirium. The results of this study may help optimize regional anesthesia techniques for hip surgery in older adults and contribute to safer, more effective postoperative pain management strategies.

Bone Marrow Aspirate Concentrate Versus Triamcinolone Injection For Hip Osteoarthritis

This is a single site, randomized single blinded, two arm study researching the effects of bone marrow aspirate concentrate (BMAC) versus Triamcinolone in patients with hip osteoarthritis. The aims and hypothesis are as follows: Specific Aim 1: Evaluate the change in pain and functional scores of a single bone marrow aspirate injection in comparison to triamcinolone in patients with hip osteoarthritis through validated patient reported outcomes scores at baseline to 12 months (6 weeks, 3 months, 6 months, and 12 months). Hypothesis: The investigators hypothesize that triamcinolone and BMAC groups will have pain reduction after each respective intervention. The changes with triamcinolone will be noticeable on the short term. The BMAC changes will take longer to have an effect but will longer duration. The investigators hypothesize that at 6 months and 1 year participants receiving BMAC will have better scores reported on the WOMAC compared to the triamcinolone injection and better than prior to injection. Specific Aim 2: Evaluate the change of bone marrow aspirate injection in comparison to triamcinolone in participant's performance on the 6 minute walk test from baseline to 12 months (6 weeks, 3 months, 6 months, and 12 months). Hypothesis: The investigators hypothesize that there will be higher walking distances on the 6 minute walk test in the participants receiving a BMAC injection in comparison to triamcinolone starting at the 3 months follow-up time. Specific Aim 3: Quantify and correlate cell characterization with patient reported outcomes score. Hypothesis: The investigators hypothesize that there will be better patient reported outcomes in patients who have a higher concentration of mesenchymal stem cells injected. The investigators will enroll 50 patients into each arm. Bone marrow will be aspirated then subsequently concentrated using the Emcyte PureBMC kit. The investigators will test the BMAC viability, rapid sterility, endotoxin, platelet concentration, volume, and total nucleated cell counts prior to injecting. The BMAC will be utilized as a hip injection into the affected hip of the patient. Patients receiving the Triamcinolone will undergo a sham bone needling to simulate the aspiration to keep patients blinded. Both groups will receive their injections under ultrasound guidance.

Effects of EDUcation and EXercise Compared to Education Alone on Clinical and Physiological Outcomes in Patients With Hip Osteoarthritis

The EDUEX trial will determine whether the addition of progressive resistance training (PRT) to a patient education program (EDU) will improve clinical outcomes in patients with hip OA. In a subsample, the effect of PRT on the articular cartilage and other structures of the hip joint is investigated. In this subsample, a comprehensive assessment of possible mechanisms underlying the effects of exercise on pain and function is undertaken. The EduEx trial will be a multicentre, stratified (by site), block randomized (allocation 1:1), controlled, parallel-group superiority trial. 150 people with hip OA will be recruited from hospitals, physiotherapy clinics, social media and newspapers. Participants will be randomized to PRT and EDU or EDU alone. All 150 participants will be included in the clinical evaluation study (CLIN). The last 40 participants randomized to PRT+EDU and to EDU, respectively, will also be included in the mechanistic (MECH) evaluation study (n=80), by being asked to participate in additional outcome assessments. The primary endpoint will be the 12 months follow-up for both the CLIN and MECH study, while a secondary endpoint will be the 3-month follow-up.

Effectiveness of a Prehabilitation Program for Hip or Knee Arthroplasty Surgery.

We live in an increasingly aging society in which the incidence of osteoarticular diseases increases, among which osteoarthritis (OA) stands out. OA is a degenerative disorder of the different components of the joint leading to a progressive destruction of the same. The hip and knee being the most affected joints, OA presents multiple symptoms such as pain, stiffness and functional limitation, also causing psychological disorders such as anxiety, depression, quality of sleep and poor perception of quality of life. Conventional treatment is aimed at alleviating symptoms, but when conservative therapies fail in the more advanced stages of the disease, total joint replacement surgery or arthroplasty is the therapeutic option of choice. Strength physical exercise (PE) and aerobic training have been shown to be effective in OA, obtaining positive effects on the symptoms and on variables that deteriorate this disease. The concept of pre-habilitation or preoperative rehabilitation has been shown through other studies in different pathologies (cardiopulmonary and musculoskeletal) to have positive effects at a clinical and functional level, however, the planning of a pre-habilitation protocol in hip or knee arthroplasty is still controversial. The purpose of this study is to determine the effect that a prehabilitation program will produce and its possible usefulness in those subjects who are waiting for a hip or knee arthroplasty. It is expected to find favorable results that support this therapy when it comes to reducing postoperative recovery times, functional capacity and other psychological variables of interest. This powerful tool could represent a non-pharmacological and non-invasive therapy, as well as being useful and economical in the management of patients with OA in advanced stages.

Return to Golf After Orthopaedic Surgery

The GOLF study is a multicenter, prospective study with the goal to investigate golfers' return to the sport following hip, knee or shoulder arthroplasty. The prevalence of return to golf, by level of returning to golf will be assessed at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Patients who are active golfers undergoing joint replacement will be identified from outpatient clinics and pre-assessment clinics and given information about the study at least two weeks prior to surgery. Participants in this study must have a desire to return to golf after surgery. Previous studies have only been able to report the return to golf after arthroplasty retrospectively; the prospective nature of this study will allow for a greater understanding of this process.

Nexus Evaluation Primary Trident II Uncemented Shell

This is a prospective cohort study assessing the survival of a new acetabula component which is based on the original Trident acetabular system (cementless shell) which is used for Total Hip Arthroplasty. The manufacturer recently introduced the evolution of this product, the Trident® II acetabular shell which was launched in 2017. This implant is CE marked and is now widely available for the UK market, however has minimal clinical outcomes data to support its use. As part of a stepwise introduction of devices to orthopaedic practice. This study will report the 10 year implant survival and patient functional outcomes of this new implant.

Influence of Antiseptic Washes on Wound Healing Complications After THA

The purpose of this research trial is to evaluate the effect of two types of washing solutions on wound healing after total hip replacement surgery. Washing solutions are used routinely during total hip replacements to clean the wound after the components have been placed and the wound is about to be closed with sutures. It is currently not known which washing solution may be better for wound healing and whether a certain solution decreases the risk of wound healing complications after total hip replacement. Therefore, this research trial is being conducted. Study participants will be randomized into one of two groups: washing the surgical wound with povidone-iodine solution (Surgiphor, Becton Dickinson, Franklin Lakes, NJ) or chlorhexidine solution (Irrisept, Irrimax Corporation, Lawrenceville, GA). All patients will undergo standard of care total hip replacements without any other change in surgery. The best type of solution that cleans the wound and potentially leads to better wound healing is unknown. This study will evaluate whether there is difference in surgical wound healing between the two washing solutions. The study will pay for the washing solutions. Patients will follow up for standard postoperative visits. At the 2-week and 6-week visits, pictures of the surgical incision will be taken and saved in the electronic medical record and evaluated in a standardized way for healing of the incision and the appearance of the scar. Postoperative complications and returns to the hospital or additional surgeries will be collected from the electronic medical record.

Alexis Retractor in Total Hip Arthroplasty

To determine if there is a difference in wound healing and surgical site infection (SSI) rates using the Alexis wound retractor vs. not using it in longitudinal direct anterior approach total hip arthroplasty.

PENG vs L-ESPB With S-ESPB for Analgesia in Total Hip Arthroplasty

The goal of this clinical trial is to evaluate whether different types of regional anesthesia can improve pain control and functional recovery after total hip arthroplasty in adult patients undergoing elective hip replacement surgery. The main questions it aims to answer are: Does the PENG block reduce opioid use in the first 48 hours after surgery more effectively than the combined L-ESPB + S-ESPB technique? Which method provides better pain relief, preserves muscle strength, and supports earlier mobilization? Researchers will compare the Pericapsular Nerve Group (PENG) block with the combination of Lumbar and Sacral Erector Spinae Plane Blocks (L-ESPB + S-ESPB) to see which provides better pain control, fewer side effects, and faster recovery. Participants will: Be randomly assigned to receive one of the two types of ultrasound-guided regional anesthesia Undergo standard hip replacement surgery under spinal anesthesia Be monitored for pain scores, opioid use, time to first walking, muscle strength, satisfaction, and side effects over the first 48 hours after surgery.

Clinical Study of Myofascial Trigger Points(MTrPs) Injection in the Treatment of Hip Osteoarthritis(OA)

Chronic musculoskeletal pain (CMP) is a common disease in China, with a high incidence among the elderly, and has a significant impact on patients' quality of life. Hip osteoarthritis is a common type of CMP. Currently, both domestic and international studies have confirmed that glucocorticoid injection at myofascial trigger points(MTrPs) can alleviate patients' pain symptoms. MTrPs injection is safe and easy to operate, and can improve the clinical management efficiency of patients with knee osteoarthritis. Therefore, we designed a prospective, randomized controlled, blinded outcome, non-inferiority study to compare the long-term clinical efficacy of glucocorticoid injection at myofascial trigger points and complex intra-articular injection in treating hip osteoarthritis. Patients will be randomly divided into two groups and receive either glucocorticoid injection at MTrPs or joint cavities. After treatment, patients will be followed up for 2 years. Their NRS scores, WOMAC scores, Patient Global Impression of Change(PGIC) scale, and adverse reactions will be recorded at 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 24 weeks. If the results indicate that the clinical efficacy of myofascial trigger point injection for knee osteoarthritis is not inferior to that of injection at intra-articular injection, it will provide a safe and simple treatment option that is easy to promote for patients who do not respond to conservative treatment.

Molecular Mechanisms Underlying Hip and Knee Osteoarthritis in Patients Undergoing Primary Elective Arthroplasty

The aim of this observational study is to determine content of rare metals and other elements, along with the levels of selected immunological parameters, in the tissue of the hip or knee joint in the course of degenerative diseases. Determining potential disturbances in the levels or functions of these parameters may in the future contribute to improving treatment - for example, through supplementation of deficient metals or modulation at the immunological level. The main question it aims to answer is: Are selected rare metals, trace elements and other selected immunological parameters lowered in the tissue of the hip or knee joint as well as in serum in the course of osteoarthritis?

Golf After Orthopaedic Surgery: A Longitudinal Follow-up (GOLF) Study

Aims The primary aim of this prospective, multi-centre study is to describe the rates of returning to golf following hip, knee and shoulder arthroplasty in an active golfing population. Secondary aims will include determining the timing of return to golf, changes in ability, handicap, and mobility, and assessing joint-specific and health-related outcomes following surgery. Methods This is a multi-centre, prospective, longitudinal study between the Hospital for Special Surgery, New York City and Edinburgh Orthopaedics, Royal Infirmary of Edinburgh, United Kingdom. Both centres are high-volume arthroplasty centres, specialising in upper and lower limb arthroplasty. Patients undergoing hip, knee or shoulder arthroplasty at either centres, and who report being golfers prior to arthroplasty will be included. Patient-reported outcome measures will obtained at 6 weeks, 3 months, 6 months and 12 months. A one-year period of recruitment will be undertaken of arthroplasty patients at both sites. Conclusions The results of this prospective study will provide clinicians with accurate data to deliver to patients with regards to the likelihood of return to golf and timing of when they can expect to return to golf following their hip, knee or shoulder arthroplasty, as well as their joint-specific functional outcomes. This will help patients to manage their postoperative expectations and plan their postoperative recovery pathway.

PENG Block vs PENG Plus Periarticular Injection vs Periarticular Injection in Older Adults

Pain after hip surgery is common in older adults and may limit early mobilization, increase the need for opioid medications, and contribute to complications such as delirium, nausea, or prolonged hospital stay. Effective postoperative pain management that preserves muscle strength and supports early rehabilitation is especially important in this population. Several analgesic strategies are currently used after hip surgery. Periarticular injection (PAI), administered by the surgeon during the procedure, is commonly used as part of standard care. The pericapsular nerve group (PENG) block is a newer ultrasound-guided regional anesthesia technique that targets the sensory nerves of the hip joint while sparing motor function. It may provide effective pain relief and facilitate early mobilization. However, it is unclear whether PENG block alone is superior to periarticular injection, and whether combining both techniques provides additional benefit. The aim of this randomized controlled clinical study is to compare three postoperative analgesic strategies in older adults undergoing hip surgery: PENG block alone, PENG block combined with periarticular injection, and periarticular injection alone. Participants will be randomly assigned to one of three study groups. The primary hypothesis is that regional anesthesia with a PENG block, either alone or combined with periarticular injection, will provide superior postoperative pain control compared with periarticular injection alone. A secondary hypothesis is that the combination of PENG block and periarticular injection will offer additional analgesic benefit compared with PENG block alone. Outcomes assessed in this study will include postoperative pain intensity, need for additional pain medications, time to first mobilization, and the occurrence of adverse events relevant to older adults, such as hypotension, excessive sedation, or postoperative delirium. The results of this study may help determine the most effective and practical analgesic strategy for hip surgery in older adults and support evidence-based optimization of postoperative pain management.

Study of the Clinical and Radiographic Results of a Fixed Polyethylene Posteriorly Stabilized Cemented Total Knee Prosthesis With a Minimum Follow-up of 1 Year.

The knee replacement market is experiencing constant growth. Alongside this growth, there is also an increasing interest in customizing implantation based on specific phenotypes to restore the morphology of the native knee. For example, in the last five years, 2019 publications on knee prosthesis alignment have been identified on PubMed. It seems worthwhile to study and analyze the performance of the prosthesis used in the Orthopedic Surgery Department of the Strasbourg University Hospitals (HUS) and to compare it with results from the literature.

Determining the Impact of a Physiotherapist-led Primary Care Model for Hip and Knee Pain - A Cluster Trial

This is a cluster randomized controlled trial to to evaluate the individual and health system impacts of implementing a new physiotherapist-led primary care model for hip and knee pain in Canada.