The first totally successful joint replacement in human subject took place in 1959. The hip was the 1 st joint to be successfully replaced.
Total arthroplasty (full joint replacement): replaces both sides of the joint e.g. acetabulum & head of the femur. Hemiarthroplasty (partial joint replacement): restore the aspect of the joint that is damaged N.B. all partial replacements may be upgraded to a full replacement at a future date if necessary.
By the degree of control offered by the joint. 1. Constrained: there is a link between the two components and all anatomical movements are restricted to a greater or lesser extent. 2. Semi-constrained: some movement is allowed in all planes. 3. Unconstrained: permits free movement in all anatomical planes. The joint is prone to dislocation until 6 weeks post-operation
Prosthetic parts are made out of inert metals of low friction coefficient (6 times > natural joint) e.g. 1. Stainless steel 2. Chrome-cobalt-molybdenum alloys 3. High density polyethylene Modern hip arthroplasties use a combination of Chrome- cobalt molybdenum alloys or stainless steel femoral shafts with high density polyethylene acetabular cup
1. Pain 2. Loss of function e.g. OA, RA, post-traumatic joint stiffness, avascular necrosis N.B. the recommended age is 60+
1. Acrylic cement : can sustain compressive stress well but cannot control shear or torsional stress.e.g. Thompson hemiarthroplasty.(fig.) 2. Bioingrowth: relies on natural growth of bone around or through the prosthetic implant and no cement is used.e.g. Austin More hemiarthroplasty.(fig.) Non-cement technique necessitate a period of non or partial weight bearing to allow stabilization of the component. Cementless technique is preferred in younger patients under 65 years
1. Anterolateral: between tensor fascia lata and glutei 2. Posterolateral: through the posterior capsule 3. True lateral: greater trochanter is excised and reatttached with wire fixation
1. Dislocation - Anterolateral & true lateral: hip will dislocate if placed in excessive extension, external rotation, and adduction or a combination of all three - Posterolateral: hip will dislocate in excessive flexion, internal rotation & adduction or a combination of all three. - 6-12 weeks these positions should be avoided. - Anteriorly Dislocated hip is shorter, externally rotatedand in extension - Posteriorly dislocated hip is shorter, flexed and internally rotated - Treatment: relocation of the hip under general anaesthesia & traction for 6 weeks
Both cemented & uncemented replacements follow a similar regime except for time of weight bearing. - Uncemented prosthesis will remain partially or non-weight bearing for 6-12 weeks. - Cemented prosthesis begins weight bearing 1 st day postoperatively. Abduction pillow or wedge should be used while patient is lying supine or on the non-operated side SLR is discouraged until full quadriceps and iliopsoas control has returned
Restoration of : 1. Joint motion 2. Muscle strength - Maintainance of: 1. Vascular function 2. Respiratory function - Education about: 1. Joint preservation techniques 2. Bed mobility 3. Weight bearing
Patient with lateral or posterolateral incisions can start weight bearing from day 1 Patients with anterolateral incision is delayed 2 days postoperatively. Start of sitting is delayed for patients with posterolateral incision to prevent dislocation In cemented joints weight bearing is increased until minimal assistance is required from a walking aid. Uncemented prosthesis will remain on cruthes or a frame for 6-12 weeks.
1. Excessive extension, external rotation & adduction with anterolateral & true lateral incision. 2. Excessive flexion, internal rotation & adduction with posterolateral incision 3. Sitting in low chairs (less than 53 cm in height) 4. Bending forward to put on shoes, socks, cut toenails, etc 5. Crossing the legs in sitting or lying 6. Twisting the legs in sitting or lying 7. Driving 8. Jumping or running 9. Contact sports
Safe transfer technique Proper use of assistive devices Postoperative exercises e.g. 1. Ankle pumps 2. Quadriceps sets 3. Gluteal sets 4. Active hip and knee flexion (heel slides) 5. Isometric hip abduction 6. Active hip abduction
Goals: A- protect healing tissues, B- prevent postoperative complications, C- improve volitional control of involved lower extremity 1. Respiratory exercises 2. Ankle pumps 3. Quadriceps sets 4. Gluteal sets 5. Repositioning of the patient every 2 hours with the abductor pillow in place
1. Same previous exercises 2. Upper extremity exercises 3. Transfer training from supine to sitting, and from sitting to standing, while observing precautions and emphasize the use of upper extremity in shifting weight, avoid pivoting on the affected leg 4. If not complaining of excessive pain, fatigue, or dizziness, gait training may begin.
1. Hip ROM exercise 2. Heel slides 3. Isometric or active assisted hip abduction 4. Active assisted short arc quadriceps sets 5. Gait training (front wheeled walker for older patients & 3-point crutch pattern for younger patients) start with 50% of body weight or less
Goal: improve UL & LL strength 1. Heel slides 2. Hip abduction 3. Terminal knee extension 4. Resisted shoulder exercises 5. Stair training (upstairs with unaffected & downstairs with affected)
1. Patient is able to demonstrate & state precautions 2. Independent with transfers 3. Independent with the exercise program 4. Independent with gait on level surfaces to 100 feet 5. Independent on stairs
Goals: A- improve strength of LL B- improve balance C- promote return to activities 1. CKC exercises 2. Pool therapy 3. Treadmill 4. single point cane. (starts 3-4 weeks after surgery & discontinued after 3-4 more weeks)). 5. Step over step stair climbing 6. Driving is allowed 3-4 weeks after surgery