Comprehensive surgical technique guide for total hip replacement via modified posterior approach, including enhanced soft tissue repair techniques, acetabular component positioning, and strategies to minimize dislocation risk
Reviewed by OrthoVellum Editorial Team
Orthopaedic clinicians and medical editors • Published by OrthoVellum Medical Education Team
Posterior Approach (Moore/Southern/Kocher-Langenbeck modified) - Most common approach worldwide, utilizing internervous plane between superior gluteal nerve (gluteus medius/minimus) and inferior gluteal nerve (gluteus maximus). Enhanced soft tissue repair critical for minimizing dislocation risk. | advanced
Location: 15-30mm posterior to hip joint capsule, exits pelvis below piriformis (85%) or through it (15%), descends posterolateral to ischial tuberosity
Protection: Keep hip flexed during external rotator release (relaxes nerve), gentle tissue handling, preserve quadratus femoris muscle, avoid excessive inferior dissection, check nerve if excessive bleeding from medial femoral circumflex artery
Injury Rate: 0.5-2% transient, less than 0.5% permanent (foot drop, sensory loss)
Location: 30-50mm proximal to greater trochanter, exits pelvis above piriformis through greater sciatic foramen, runs between gluteus medius and minimus
Protection: Avoid proximal dissection beyond greater trochanter, stay inferior to safe zone (5cm above GT), limit superior retractor placement, no dissection above piriformis
Injury Rate: Less than 0.5% (Trendelenburg gait, abductor weakness)
Location: 30-50mm medial to anterior hip joint, lies on iliopsoas muscle, femoral nerve lateral, artery central, vein medial
Protection: Stay on bone with anterior acetabular retractors, avoid medial perforation during reaming, careful with anterior screw placement, no excessive medial wall reaming
Injury Rate: Rare less than 0.1% (catastrophic if occurs)
Location: Branches from profunda femoris, runs posteriorly between external rotators, supplies femoral head and short external rotators
Protection: Control bleeding with electrocautery, avoid excessive stripping of short external rotators, ligate if needed
Injury Rate: Common minor bleeding source (rarely significant)
Location: Variable position 20-50mm medial to ASIS, crosses iliacus muscle, runs under inguinal ligament medial to ASIS
Protection: Minimize anterior dissection, protect if visible during direct anterior or anterolateral approaches
Injury Rate: 1-2% (meralgia paresthetica - lateral thigh numbness)
Superficial Layers
Deep Layers - Short External Rotators (Superficial to Deep)
Posterior Hip Capsule
Neurovascular Structures
Internervous Plane
Acetabular Landmarks
Femoral Landmarks
| Complication | Recognition | Prevention | Management |
|---|---|---|---|
| **Dislocation** (2-5% without repair, 1-2% with enhanced repair) - Most common major complication | Sudden pain, audible 'pop', leg shortened and internally rotated (posterior dislocation) or flexed/externally rotated (anterior dislocation). X-ray confirms: loss of femoral head-acetabular relationship. Most occur within 3 months, 50% within 6 weeks | Enhanced posterior repair (capsule + rotators), adequate cup anteversion (20°), combined anteversion 30-35°, larger head size (36mm better than 28mm), appropriate offset, avoid impingement, patient education on precautions, dual mobility in high-risk patients | First dislocation: closed reduction under sedation (emergency), postreduction X-ray, CT to rule out fracture, extend precautions to 12 weeks, abduction orthosis. Recurrent dislocation (greater than 2): revision surgery - assess cup position, consider dual mobility liner, revision to anterior approach, or constrained liner. Chronic dislocation: Girdlestone or revision |
| **Periprosthetic Femur Fracture** (1-3% primary, 5-10% revision, higher in elderly/osteoporotic) | Intra-operative: sudden loss of resistance, audible crack, visible fracture. Postoperative: pain, inability to bear weight, shortening/rotation. X-ray: fracture line, stem subsidence. Vancouver classification: AG (greater trochanter), AL (lesser trochanter), B1 (stem stable), B2 (stem loose), B3 (poor bone stock), C (below stem) | Avoid varus broaching, gentle technique, adequate canal preparation, appropriate stem size (avoid undersizing), treat osteoporosis, consider cemented stems in high-risk, extended trochanteric osteotomy if difficult exposure in revision | **Intra-operative recognition**: Vancouver AG/AL (greater/lesser trochanter) - cable/wire cerclage, protected weight bearing. Vancouver B1 (stem stable) - ORIF with plate/cables around stable stem. Vancouver B2 (stem loose) - revision to longer stem bypassing fracture by 2 cortical diameters + ORIF. Vancouver B3 (poor bone stock) - impaction grafting + revision + ORIF or allograft-prosthesis composite. Vancouver C (below stem) - ORIF with plate. **Postoperative**: Treat based on Vancouver classification |
| **Sciatic Nerve Injury** (0.5-2% transient, less than 0.5% permanent) - Foot drop, sensory loss | Immediate postoperative: inability to dorsiflex foot/toes (foot drop), numbness lateral leg/foot, weakness plantar flexion (less common). EMG/NCS at 3 weeks confirms level and severity. MRI if concern for hematoma compression | Keep hip flexed during external rotator release (relaxes nerve), gentle tissue handling, preserve quadratus femoris, avoid excessive inferior dissection, limit leg lengthening (less than 4cm - stretches nerve), avoid posterior retractor pressure, check nerve if excessive medial femoral circumflex bleeding | **Immediate**: Remove all retractors, extend hip to relax nerve, assess severity (complete vs incomplete). **Early** (less than 24 hours): If complete palsy or hematoma, consider exploration and decompression. **Conservative**: AFO (ankle-foot orthosis) for foot drop, physiotherapy, monitor recovery. **Recovery**: Most recover 6-12 months if neuropraxia. Poor recovery if nerve transected/neurotmesis. Consider late tendon transfers if no recovery by 12 months (tibialis posterior to tibialis anterior for foot drop) |
| **Leg Length Discrepancy** (Most common patient complaint and medicolegal issue, 10-30% patients perceive difference) | Patient reports feeling of leg length difference. Clinical: measure ASIS to medial malleolus bilaterally, assess pelvic tilt. Radiographic: measure from teardrop to lesser trochanter bilaterally on AP pelvis. Functional: gait analysis, shoe lift trial | Careful pre-operative templating, intra-operative measurement from fixed pelvic point (ASIS, iliac crest) to medial malleolus, trial reduction assessment, compare to contralateral knee/malleoli, target equal or 5mm lengthening (patients tolerate lengthening better than shortening), avoid overlengthening greater than 10mm | **Less than 10mm**: Usually asymptomatic, reassurance, most patients adapt. **10-20mm**: Symptomatic, shoe lift (heel raise 5-10mm in shoe), physiotherapy for gait training and core strengthening. **Greater than 20mm**: Consider revision surgery if patient intolerant and no contraindications - shorten femoral component with offset options or revision with shorter neck/smaller head. Prevention better than treatment - medicolegal risk high |
| **Heterotopic Ossification** (10-30% incidence, usually asymptomatic, 1-3% severe with ankylosis) | Early: pain, swelling, decreased ROM, elevated alkaline phosphatase (ALP). Late: progressive stiffness, limited ROM, mature bone on X-ray (12 weeks). Brooker classification: I (islands), II (less than 1cm gap), III (less than 1cm gap), IV (ankylosis) | **High-risk patients**: Previous HO, ankylosing spondylitis, DISH, head injury, male, hypertrophic OA. **Prophylaxis options**: NSAIDs (indomethacin 75mg BD for 6 weeks - most common in Australia), OR single-dose radiation (7-8 Gy preop or postop within 72 hours). Minimize soft tissue trauma, remove bone debris, gentle technique | **Mild (Brooker I-II)**: No treatment needed, ROM exercises. **Severe (Brooker III-IV)**: Wait 12-18 months for maturation (bone scan 'cold'), excision with prophylaxis (NSAIDs or radiation to prevent recurrence). Excision without prophylaxis has 50-90% recurrence rate. Consider excision if significantly limits function |
| **Infection** (0.5-1% primary THR, 2-5% revision, devastating complication) | **Early** (less than 3 months): Wound drainage, erythema, fever, pain, elevated CRP/ESR. **Delayed** (3-24 months): Pain, implant loosening, elevated inflammatory markers. **Late** (greater than 24 months): Chronic pain, sinus tract, loosening. Aspiration: WBC greater than 3000, PMN greater than 80%, positive culture (gold standard) | Laminar flow OR, antibiotic prophylaxis (cefazolin 2g pre-incision, continue 24 hours), chlorhexidine-alcohol skin prep, minimize OR traffic, double gloving, antibiotic cement if using cement, minimize operative time, gentle tissue handling (avoid devitalization), consider screening/decolonization for MRSA in high-risk | **Acute** (less than 3 weeks, stable implants): DAIR (Debridement, Antibiotics, Irrigation, Retention) - open debridement, liner exchange, 6-12 weeks IV antibiotics. Success 50-70%. **Chronic or loose implants**: Two-stage revision (gold standard in Australia) - remove components, antibiotic spacer (6 weeks IV + PO antibiotics), ESR/CRP normalization, re-implant. Success 85-95%. **One-stage revision**: Selected cases (known organism, healthy host). **Suppression**: Non-surgical candidate, chronic antibiotics lifelong |
| **DVT/PE** (DVT 1-2% with chemoprophylaxis, PE 0.1-0.5%, fatal PE 0.1%) | **DVT**: Calf pain/swelling, Homan's sign (low sensitivity), Wells score, D-dimer (high NPV), duplex ultrasound (gold standard for diagnosis). **PE**: Dyspnea, chest pain, tachycardia, hypoxia, hemoptysis (rare). CTPA confirms (gold standard) | Mechanical prophylaxis: early mobilization, TED stockings, pneumatic compression. Chemical prophylaxis: LMWH (enoxaparin 40mg SC daily) OR DOAC (rivaroxaban 10mg PO daily, apixaban 2.5mg BD) for 35 days (Australian guidelines). Regional anesthesia (spinal/epidural) reduces risk vs GA | **DVT**: Therapeutic anticoagulation - DOAC (rivaroxaban 15mg BD 3 weeks then 20mg daily, apixaban 10mg BD 1 week then 5mg BD) OR LMWH bridge to warfarin (INR 2-3). Duration 3-6 months. **PE**: Hemodynamically stable - anticoagulation as above. **Massive PE** (unstable): ICU, thrombolysis (tPA), embolectomy (surgical or catheter-based), IVC filter. **Recurrent despite anticoagulation**: IVC filter |
| **Superior Gluteal Nerve Injury** (less than 0.5%, Trendelenburg gait, abductor dysfunction) | Trendelenburg gait (pelvis drops on contralateral side during stance), positive Trendelenburg test (unable to maintain pelvis level when standing on affected leg), weakness of abduction. EMG confirms gluteus medius/minimus denervation. May be partial or complete | Avoid proximal dissection beyond 5cm above greater trochanter, limit superior retractor placement (superior gluteal nerve exits pelvis above piriformis), stay in safe zone during exposure, avoid excessive proximal stripping during revision surgery | **Conservative** (most cases): Physiotherapy for compensation (hip flexors, TFL), gait training, abductor strengthening, assistive device (cane in opposite hand reduces load). Most partially recover 6-12 months. **Severe/persistent**: Consider abductor reconstruction (vastus lateralis slide, gluteus maximus transfer), or revision with constrained liner (prevents dislocation despite weak abductors). Complete recovery rare if nerve transected |
| **Vascular Injury** (Rare less than 0.1%, but catastrophic - external iliac, medial femoral circumflex, superior gluteal arteries) | **Intra-operative**: Sudden bleeding, expanding hematoma, hemodynamic instability (tachycardia, hypotension). **Postoperative**: Dropping hemoglobin, expanding thigh hematoma, compartment syndrome, distal ischemia (absent pulses, cool foot, pain). **Delayed**: Pseudoaneurysm, AV fistula (weeks to months later) | Gentle tissue handling, stay on bone with anterior acetabular retractor (iliopsoas protects femoral vessels), avoid medial acetabular perforation during reaming, careful with anterior screw placement (safe zone posterosuperior), avoid anterior reaming/cup protrusion, control medial femoral circumflex branches during rotator release | **Recognition crucial**: Have vascular surgeon available. **External iliac injury**: IMMEDIATE vascular repair - direct repair if laceration, interposition graft if transection. Fasciotomy if ischemia time greater than 4 hours. **Medial circumflex**: Usually controlled with electrocautery, packing, rarely requires ligation. **Pseudoaneurysm**: Endovascular stent OR open repair. **AV fistula**: Endovascular embolization OR open repair. Mortality high if delayed recognition |
| **Trunnionosis/Taper Corrosion** (1-5%, inadequate head impaction, large heads, dual taper stems) | Pain, swelling, metallosis, elevated chromium/cobalt levels, ALVAL (aseptic lymphocytic vasculitis-associated lesion) on MRI - fluid collections, pseudotumors, soft tissue destruction. May present years after surgery. Metal artifact reduction sequence (MARS) MRI best imaging | **Adequate head impaction** (critical - 5-8 firm hits), clean and dry both tapers (stem trunnion, head bore) before assembly, avoid mismatched metals (use cobalt-chrome head with cobalt-chrome taper), minimize dual tapers (modular neck systems higher risk), consider ceramic heads (no corrosion), avoid excessive head offset/large heads | **Asymptomatic with low metal ions**: Observation, monitor metal ions annually (chromium, cobalt). **Symptomatic or elevated ions (greater than 7 ppb)**: MARS MRI to assess soft tissue. **ALVAL/pseudotumor/symptoms**: Revision surgery - remove head and stem, aggressive debridement of metallosis, consider ceramic-on-polyethylene bearing, metal ion monitoring postoperatively. ALVAL may not reverse after revision (permanent damage) |
Practice these scenarios to excel in your viva examination
"How does the posterior approach compare to the direct anterior approach for primary total hip replacement?"
"What is the enhanced posterior repair technique and what evidence supports its use in reducing dislocation after posterior approach THR?"
"How do you protect the sciatic nerve during the posterior approach to the hip, and what would you do if you recognized a sciatic nerve injury postoperatively?"
High-Yield Exam Summary
Pellicci PM, Bostrom M, Poss R. Posterior approach to total hip replacement using enhanced posterior soft tissue repair. Clin Orthop Relat Res. 1998;(355):224-228. doi:10.1097/00003086-199810000-00023 - Landmark RCT demonstrating capsular repair reduces dislocation from 5.8% to 0.6% after posterior approach THR
Kwon MS, Kuskowski M, Mulhall KJ, Macaulay W, Brown TE, Saleh KJ. Does surgical approach affect total hip arthroplasty dislocation rates? Clin Orthop Relat Res. 2006;447:34-38. doi:10.1097/01.blo.0000218746.84494.df - RCT confirming enhanced posterior repair significantly reduces dislocation risk
Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report. Adelaide: AOA; 2023. - Comprehensive registry data showing 10-year revision rates ~5% for primary THR with uncemented fixation
Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am. 1978;60(2):217-220. - Classic study defining safe zone for acetabular component positioning (30-50° inclination, 10-30° anteversion)
Berstock JR, Blom AW, Beswick AD, et al. Mortality after total hip replacement surgery: a systematic review. Bone Joint Res. 2014;3(6):175-182. doi:10.1302/2046-3758.36.2000239 - Systematic review of mortality rates and risk factors following primary THR
Suh KT, Park BG, Choi YJ. A posterior approach to the hip with posterior soft-tissue repair for primary total hip replacement. J Bone Joint Surg Br. 2004;86(3):334-338. doi:10.1302/0301-620x.86b3.14432 - Study demonstrating capsular and external rotator repair reduces dislocation by 69%
Meek RM, Allan DB, McPhillips G, Kerr L, Howie CR. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res. 2006;447:9-18. doi:10.1097/01.blo.0000218754.12311.4a - Comprehensive review of dislocation epidemiology, risk factors, and prevention strategies
Berry DJ, von Knoch M, Schleck CD, Harmsen WS. Effect of femoral head diameter and operative approach on risk of dislocation after primary total hip arthroplasty. J Bone Joint Surg Am. 2005;87(11):2456-2463. doi:10.2106/JBJS.D.02860 - Large series demonstrating larger femoral heads (36mm vs 28mm) reduce dislocation risk
Masonis JL, Bourne RB. Surgical approach, abductor function, and total hip arthroplasty dislocation. Clin Orthop Relat Res. 2002;(405):46-53. doi:10.1097/00003086-200212000-00006 - Review of surgical approaches and their impact on abductor function and dislocation rates
Therapeutic Guidelines Ltd. eTG complete [digital]. Melbourne: Therapeutic Guidelines Limited; 2023. Available from: https://www.tg.org.au - Australian antibiotic guidelines for surgical prophylaxis and DVT prevention in orthopaedic surgery