Joint Replacement — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Joint replacement (arthroplasty) is orthopaedic surgery to remove a diseased, damaged, or worn joint and replace it with a carefully engineered prosthetic implant that replicates the anatomy and biomechanics of the natural joint. The most common joints replaced are the hip (total hip arthroplasty, THA) and knee (total knee arthroplasty, TKA), performed over 1.5 million times annually in the United States alone. Other joints amenable to replacement include the shoulder (anatomical total shoulder arthroplasty or reverse shoulder arthroplasty), elbow (total elbow arthroplasty for rheumatoid arthritis), ankle, and small finger joints. Implant materials are selected for biocompatibility and wear resistance: cobalt-chromium and titanium alloy metal components, ultra-high-molecular-weight polyethylene (UHMWPE) bearings, and alumina or zirconia ceramic heads and liners. Fixation is achieved by bone cement (PMMA acrylic cement), cementless porous ingrowth surfaces, or hybrid constructs combining both. Computer-assisted navigation and robotic-arm systems (MAKO, ROBODOC) improve implant positioning accuracy and are associated with reduced outlier placement and potentially lower revision rates. Joint replacement is among the most cost-effective major surgical interventions in modern medicine.

This treatment represents an important component of modern medical management, supported by clinical evidence from multiple randomised controlled trials and systematic reviews. Treatment protocols are continually refined based on emerging evidence to optimise patient outcomes while minimising treatment burden.

Patient suitability is assessed through a structured multidisciplinary evaluation incorporating clinical history, physical examination findings, and results of relevant investigations. Treatment planning considers the full clinical context including disease characteristics, patient comorbidities, functional status, and individual treatment goals to ensure the most appropriate therapeutic approach is selected for each patient.

Joint replacement is indicated for patients with end-stage joint disease causing severe, persistent pain and functional limitation that significantly impairs quality of life and daily activities despite comprehensive non-operative management. Age is not the primary criterion — functional impact and quality of life are. Specific indications include primary osteoarthritis (the most common cause — progressive articular cartilage loss with subchondral bone changes, joint space narrowing, and osteophyte formation), rheumatoid arthritis and other inflammatory arthropathies causing joint destruction, post-traumatic arthritis from prior fracture or ligament injury damaging articular surfaces, avascular necrosis (osteonecrosis) from corticosteroid use, alcohol excess, or sickle cell disease, and ankylosing spondylitis causing hip ankylosis. Surgery is considered when pain is severe and limiting most daily activities, walking is restricted to less than 15–30 minutes, sleep is disturbed by pain, conservative treatments (physiotherapy, NSAIDs, intra-articular corticosteroid and hyaluronic acid injections, weight loss, walking aids, TENS) have been adequately tried and failed, and radiographic evidence confirms joint destruction. Functional limitation rather than X-ray severity drives the timing decision.

Total knee arthroplasty (TKA): Under spinal or general anaesthesia (with or without peripheral nerve block for post-operative analgesia), a medial parapatellar or subvastus approach provides exposure. A tourniquet inflates around the thigh. Precision cutting guides or robotic-arm navigation resect the distal femur and proximal tibia at the planned bone cuts. The distal femur is resected in five planes to accept the femoral component; the tibia is cut perpendicular to its mechanical axis. A trial reduction assesses alignment, balance, and range of motion. Final cemented or cementless femoral, tibial, and patellar (optional) components are implanted. A polyethylene tibial insert is placed between the metal tibial tray and the femoral condyles. Total hip arthroplasty (THA): The femoral head is resected, acetabulum reamed, cup impacted and fixed, stem inserted into the femoral canal, and the appropriate femoral head and liner bearing matched. Both procedures employ intraoperative fluoroscopy or computer navigation for implant alignment. Drains and wound closure complete the procedure. Other joints follow analogous principles adapted to joint anatomy. Robotic-arm systems (MAKO) provide haptic feedback to maintain bone cuts within pre-planned boundaries to a precision of 0.5–1 mm.

The procedure is performed in an appropriately equipped facility by experienced specialist clinicians. Prior to commencement, the patient undergoes pre-procedural assessment including vital signs measurement, review of relevant investigations, and confirmation of informed consent. Intravenous access is established and monitoring equipment including ECG, pulse oximetry, and blood pressure monitoring is applied.

The procedural site is prepared according to aseptic technique standards. Anaesthesia or analgesia is administered as appropriate for the specific procedure and patient needs, ranging from local anaesthesia for minor procedures to regional or general anaesthesia for more complex interventions.

The procedure is performed under direct visualisation or image guidance as appropriate. Key technical steps are executed with attention to anatomical landmarks and patient safety parameters. Haemostasis is achieved and confirmed before completion. Post-procedural assessment includes clinical evaluation of the immediate result, complication surveillance, and documentation of the procedure.

Recovery room monitoring continues until the patient meets defined discharge criteria. Written post-procedural instructions covering activity restrictions, wound care, medication management, and symptoms requiring urgent review are provided before discharge.

Hip and knee joint replacements achieve 90–95% implant survival at 10 years and approximately 80–85% at 20 years based on data from national joint registries covering millions of procedures. Patient satisfaction exceeds 90% for THA and 80–85% for TKA at 1 year. Pain relief is dramatic and sustained: Oxford Hip Score and Oxford Knee Score improve by 20–30 points from baseline after arthroplasty. Walking ability, stair climbing, and activities of daily living improve significantly within the first 6–12 weeks. Health-related quality-of-life metrics (SF-36, EQ-5D) return to population-normal levels for most patients by 12 months. Shoulder replacement for rotator cuff arthropathy treated with reverse total shoulder arthroplasty (RTSA) achieves functional forward elevation improvement from 40° to over 140° in most patients. Ankle replacement achieves comparable 10-year implant survival (80–90%) and better motion preservation than ankle arthrodesis, with equivalent pain relief. Hospital volume and surgeon experience strongly influence outcomes — specialist centres report lower complication and revision rates.

DVT and pulmonary embolism are managed with extended anticoagulation (LMWH or rivaroxaban for 14–35 days depending on joint) and mechanical compression. Prosthetic joint infection (PJI) is the most feared complication: it affects 1–2% of primary arthroplasties and requires extensive treatment including two-stage revision surgery (implant removal, antibiotic spacer, reimplantation) or joint fusion. Risk factors include obesity, diabetes, immunosuppression, and previous wound problems. Aseptic loosening — the leading cause of late failure — results from wear particle-induced osteolysis and affects 5–10% of implants at 15–20 years. Dislocation after THA occurs in 1–3% and after TKA in under 1%. Stiffness after TKA affects 5–10% and may require manipulation under anaesthesia or revision to a flexion-enabling design. Periprosthetic fracture occurs in 0.5–1%. Nerve injury (sciatic nerve, THA; peroneal nerve, TKA) causes foot drop in under 1%. Vascular injury is rare (<0.1%) but potentially limb-threatening. Leg length discrepancy after THA (>10 mm) and patellar complications after TKA (clunk, maltracking) are implant-specific concerns. Smoking, obesity, and diabetes multiply complication rates and reduce implant longevity.

Enhanced recovery after surgery (ERAS) protocols enable mobilisation within 4–6 hours of surgery. Physiotherapy commences the same day, progressing from standing to walking with a frame within 24 hours. Hospital discharge at 2–5 days for uncomplicated primary arthroplasty. A walking aid (frame, then elbow crutch) is used for 4–6 weeks. Physiotherapy continues as an outpatient for 6–12 weeks, progressing from gait retraining and range of motion to strengthening and functional activities. For TKA, target knee flexion of 90° by 2 weeks and 120° by 6 weeks is standard. Driving resumes at 6–8 weeks for lower limb surgery. Return to desk work at 4–6 weeks; physical jobs at 3–6 months. Anticoagulation continues for 14 (TKA) to 35 (THA) days post-operatively. Hip and knee replacement precautions vary by joint and approach — your physiotherapist and surgeon provide specific guidance. Annual follow-up with clinical review and X-ray at 1, 5, and 10 years detects early implant problems before clinical failure. Dental procedures with bacteraemia risk require antibiotic prophylaxis discussion with the treating orthopaedic surgeon for 2 years post-arthroplasty.