Step 1: Patient Positioning and Landmarks
Patient Position: Supine on standard operating table OR radiolucent table with extension attachment. Pelvis secured with padded supports/posts to prevent rotation. Operative leg free to extend, externally rotate, and adduct off side of table. Non-operative leg abducted 30-40° in leg holder or support. Entire operative limb prepped from iliac crest to mid-tibia.
Key Landmarks: Palpate and mark ASIS, greater trochanter (GT), femoral pulse (medial boundary). Measure distance from ASIS to GT - typically 10-12cm. Plan incision 2-3cm distal and lateral to ASIS.
Table Setup: C-arm from contralateral side if using intra-operative imaging. Mayo stand on operative side. Ensure table breaks allow hip extension or use extension attachment/fracture table configuration.
Positioning Checks: Confirm pelvis level with C-arm (if available) - rotation causes leg length error and cup malposition. Test leg mobility - hip must extend, externally rotate, and adduct for femoral exposure.
Exam Pearl
Technical Mastery: Supine positioning is fundamental DAA advantage: (1) Accurate leg length assessment through direct comparison, (2) Easy intra-operative fluoroscopy for cup verification, (3) Facilitates bilateral cases, (4) Gravity-assisted femoral exposure with leg off table. Pelvic rotation is enemy of accuracy - must ensure level pelvis.
Critical Positioning Errors
- Pelvic tilt/rotation (causes cup malposition and leg length discrepancy)
- Inadequate table configuration (inability to extend hip for femoral exposure = abort case)
- Contralateral leg not cleared (blocks hip adduction for femoral prep)
- Insufficient fluoroscopy access (inability to verify position intra-operatively)
Step 2: Skin Incision and Superficial Dissection
Incision: Longitudinal or slightly oblique incision beginning 2-3cm distal and lateral to ASIS, extending 8-12cm distally (parallel to line from ASIS to lateral patella). Smaller incisions possible with experience (6-8cm), but adequate exposure essential early in learning curve.
Subcutaneous Dissection: Deepen through subcutaneous fat to fascia. Identify LFCN in fat - typically medial aspect of incision, running with sartorius. Variable branching pattern (identify main trunk and branches). If nerve visible, protect with vessel loop or gentle medial retraction. If not visible, careful medial retraction of sartorius usually protects nerve.
Fascial Layer: Identify palpable interval between TFL (lateral - firmer, more vertical) and sartorius (medial - softer, more oblique). May be filled with fat and loose areolar tissue.
Exam Pearl
Avoiding Most Common Complication: LFCN injury occurs in 15-30% (transient) and 5% (permanent). Prevention: (1) Incision 2-3cm distal/lateral to ASIS (not directly over ASIS where nerve branches), (2) Identify nerve in subcutaneous fat if visible, (3) Gentle medial retraction with sartorius (nerve runs with sartorius), (4) Avoid excessive traction. Counsel patients pre-operatively about temporary numbness risk.
Dangers - Superficial Dissection
- LFCN injury (most common complication) - causes meralgia paresthetica
- Incision too medial (endangers femoral neurovascular bundle)
- Incision too lateral (difficult interval, may violate TFL muscle belly)
- Inadequate incision length (limits deep exposure, increases retraction injury risk)
Step 3: Deep Interval and Fascial Division
Fascial Incision: Incise fascia in interval between TFL (lateral) and sartorius (medial). Use finger dissection to develop plane - blunt dissection safer than sharp (protects LFCN, vascular structures).
Rectus Femoris Identification: Deep to interval lies rectus femoris. Two heads: (1) Reflected head from anterior hip capsule (superior), (2) Straight head from AIIS (anterior). Expose anterior surface of rectus femoris.
LFCA Management: Identify ascending branch of lateral femoral circumflex artery (LFCA) - typically 2-3cm distal to hip capsule, runs DEEP to rectus femoris, easily palpable pulsatile vessel. Ligate/cauterize vessel with bipolar or ties. Failure to control LFCA results in troublesome bleeding throughout case.
Interval Development: Retract TFL laterally with deep retractor, sartorius and rectus femoris medially. Release reflected head of rectus femoris from superior capsule if needed for exposure (improves access to superior acetabular rim).
Exam Pearl
Vascular Landmark: Ascending branch LFCA is critical landmark - lies 2-3cm distal to anterior hip capsule, runs under rectus femoris. MUST identify and ligate early (before capsular exposure) to prevent bleeding. Arises from MFCA or directly from profunda femoris. Motor branch to vastus lateralis often accompanies vessel - preserve if possible.
Dangers - Deep Interval
- LFCA bleeding if not identified/ligated (obscures field throughout case)
- Femoral nerve injury with aggressive medial retraction (stay on bone)
- Superior gluteal nerve injury if dissection too proximal (above GT level)
- Damage to motor branch to vastus lateralis (accompanies LFCA)
Step 4: Capsule Exposure and Capsulotomy
Capsule Visualization: Sweep periosteum and soft tissue off anterior hip capsule with periosteal elevator and retractors. Capsule typically thick (iliofemoral ligament - Y ligament of Bigelow).
Retractor Placement: (1) Lateral retractor over femoral neck (protects abductors), (2) Medial retractor over anterior acetabular rim/pubis (protects femoral neurovascular bundle - MUST be on bone), (3) Superior retractor if needed (avoid proximal dissection).
Capsulotomy Pattern: T-shaped (longitudinal + transverse) or H-shaped capsulotomy for maximum exposure. Extend longitudinal limb along femoral neck. Release anterior capsule generously - tight capsule severely limits exposure and increases fracture risk.
Superior Capsule Release: Release reflected head of rectus femoris from superior capsule for improved visualization of superior acetabular rim (important for accurate cup positioning).
Exam Pearl
Capsular Release = Safe Femoral Exposure: Adequate capsular release is ESSENTIAL for safe femoral exposure (most challenging DAA step). Tight anterior capsule limits hip extension and femoral visualization, dramatically increasing periprosthetic fracture risk. Be generous with anterior capsular release. Most surgeons do NOT repair capsule at closure (posterior capsule preservation provides stability).
Dangers - Capsulotomy
- Inadequate capsular release (poor femoral visualization = high fracture risk)
- Femoral nerve injury with medial retractor (must stay on bone)
- Abductor injury with lateral retractor if placed too posterior/superior
- Vascular injury if medial retractor slips off bone into femoral vessels
Step 5: Femoral Neck Osteotomy
Neck Visualization: With capsule open, visualize femoral head and neck. Identify junction of head and neck, lesser trochanter (landmark for cut level).
Osteotomy Level: Standard femoral stem - cut approximately 1cm ABOVE lesser trochanter. High-offset stems may require different level (check templating). Mark level with electrocautery or marking pen.
Osteotomy Execution: Use oscillating saw for controlled cut. Protect posterior structures with retractor while sawing. Angle cut to match templated stem anteversion (typically 10-15°).
Head Removal: Place corkscrew extractor into femoral head. Remove head with gentle rocking/twisting motion. Protect acetabular rim with retractor during extraction.
Head Disposition: Send head for cultures (always - even primary OA), histology, and use for trial cup sizing (femoral head diameter approximates cup outer diameter minus wall thickness ~8-10mm).
Exam Pearl
Neck Osteotomy Precision: Cut level determines offset and leg length. Standard cut = 1cm above lesser trochanter for most cementless stems. Too high = reduced offset (abductor dysfunction, instability); Too low = difficulty seating stem (subsidence risk, may require shortening osteotomy). Send head for cultures even in primary OA (pre-existing infection 0.5-1%, must exclude before implanting).
Dangers - Neck Osteotomy
- Cut too high (inadequate offset, leg shortening, abductor dysfunction)
- Cut too low (stem insertion difficulty, subsidence risk, fracture risk)
- Posterior acetabular wall fracture during head extraction
- Periprosthetic fracture if head extraction requires excessive force
Step 6: Acetabular Exposure and Preparation
Retractor Configuration: Three-retractor setup: (1) Anterior over pubis/anterior rim, (2) Lateral over femoral neck stump, (3) Posterior under neck stump protecting posterior column. Retractors must be on bone (especially medial/anterior to protect femoral vessels).
Labrum Excision: Remove acetabular labrum circumferentially with electrocautery or rongeur. Complete labrum removal essential for proper cup seating and visualization of acetabular rim.
Anatomical Landmarks: Identify transverse acetabular ligament (TAL) - marks inferior acetabular rim and native version (cup parallel to TAL = ~20° anteversion). Identify anterior/posterior walls, floor (medial wall), superior rim.
Soft Tissue Clearance: Remove pulvinar (fat pad) from acetabular floor with curette. Clear all soft tissue from acetabulum - residual tissue causes proud cup, reduced bone contact, or impingement.
Osteophyte Removal: Remove peripheral osteophytes with osteotome or rongeur (especially anteroinferior and posteroinferior) - interfere with cup seating and cause impingement.
Exam Pearl
TAL = Version Reference: Transverse acetabular ligament is critical anatomical landmark - marks inferior rim and provides reliable reference for native version. Cup oriented PARALLEL to TAL approximates 15-25° anteversion (normal native version ~20°). Alternative reference in DAA: anterior pelvic plane (APP) - reliably oriented in supine position, cup parallel to APP = ~20° anteversion.
Dangers - Acetabular Exposure
- Posterior wall fracture with posterior retractor (stay below equator)
- Femoral neurovascular injury if anterior retractor off bone
- Inadequate labrum/soft tissue clearance (proud cup, poor contact, impingement)
- Loss of TAL during labrum excision (lose version reference)
Step 7: Acetabular Reaming
Starting Reamer: Begin 2-4mm smaller than templated cup size. Center reamer on acetabular floor (avoid eccentric reaming).
Reaming Technique: Ream to subchondral bone - look for "bleeding dot sign" (punctate bleeding from healthy bone). Progressive reaming in 1-2mm increments until achieving good peripheral rim fit.
Final Reamer Size: Ream to size 1-2mm SMALLER than intended cup for press-fit (line-to-line fit). Example: final reamer 52mm = cup 54mm.
Reaming Orientation: Target Lewinnek safe zone - 40° inclination (30-50°), 20° anteversion (10-30°). Use anatomical references: TAL for version, lateral acetabular wall for inclination. Intra-operative fluoroscopy confirms position.
Depth Assessment: Avoid excessive medial reaming (weakens floor, risks protrusio, intrapelvic perforation). Ream to bleeding subchondral bone, not through floor. Acetabular depth approximately 25-30mm in normal hip.
Rim Coverage: Assess bone coverage after reaming - need 70-80% rim contact for stable press-fit. Consider jumbo cup, medialization, or augments if inadequate coverage.
Exam Pearl
Reaming Strategy: "Ream until you see the dots" - bleeding dot sign indicates healthy subchondral bone contact. Final reamer 1-2mm SMALLER than cup = optimal press-fit (0.5-1mm interference). Avoid excessive medial reaming (weakens floor, risks intrapelvic perforation especially in elderly osteoporotic bone or RA with protrusio). Target 40/20 (inclination/anteversion) using TAL or APP as reference.
Dangers - Reaming
- Excessive medial reaming (floor fracture, protrusio, intrapelvic perforation)
- Under-reaming (inadequate cup fixation, micromotion, loosening)
- Over-reaming (reduced bone contact, rim fractures, loosening)
- Posterior wall fracture during reaming (most common acetabular fracture)
Step 8: Acetabular Cup Insertion
Cup Selection: Choose cup 1-2mm LARGER than final reamer for press-fit. Ensure correct liner option available (constrained if instability concern, dual-mobility in high-risk patients).
Cup Orientation: Align inserter to target position - 40° inclination, 20° anteversion. Use references: TAL, APP, fluoroscopy. DAA advantage: supine position allows reliable use of APP and easy fluoroscopy.
Cup Impaction: Impact cup with firm, progressive mallet strikes. Cup should advance into bone with each strike. Final position: fully seated against rim, no rocking/micromotion with trial liner inserted.
Stability Assessment: Insert trial liner, check for micromotion. Stable cup = no movement with trial liner toggled. Micromotion indicates inadequate press-fit - add screws.
Screw Fixation: Indications for screws: (1) Poor bone quality (osteoporosis, RA, AVN), (2) Large cup (>60mm), (3) Inadequate press-fit, (4) Dysplasia, (5) Revision setting. Safe zone for screws: 10 o'clock to 2 o'clock on right hip (2 o'clock to 10 o'clock left hip) - posterosuperior quadrant. AVOID anteroinferior (iliac vessels) and posteroinferior (sciatic nerve).
Position Verification: Check cup position with fluoroscopy (AP and lateral views). Verify inclination, anteversion, depth, absence of protrusion.
Exam Pearl
Cup Fixation Principles: Press-fit requires 1-2mm cup-bone interference (final reamer 52mm = cup 54mm). Screws augment fixation but don't substitute for inadequate press-fit. Safe screw zone = posterosuperior quadrant (10-2 o'clock right hip) avoiding vessels anteroinferiorly and sciatic nerve posteroinferiorly. DAA supine positioning facilitates intra-operative imaging for position verification before femoral preparation.
Dangers - Cup Insertion
- Cup malposition (excessive anteversion >30° or inclination >50° = instability risk)
- Medial wall fracture during impaction (elderly/osteoporotic bone)
- Screw penetration anteroinferiorly (external iliac vessels) or posteroinferiorly (sciatic nerve)
- Inadequate press-fit (micromotion, early loosening, squeaking)
Step 9: Femoral Exposure (Most Challenging Step)
Hip Positioning: CRITICAL step requiring adequate hip extension and external rotation. Flex hip 30-45°, then extend by: (1) Bringing operative leg OFF side of table (standard table), OR (2) Using table extension/fracture table attachment.
Capsular Release Check: Ensure adequate anterior capsular release from Step 4. Inadequate release = impossible femoral visualization = high fracture risk. Release more capsule if needed including posterior capsule.
Leg Position: Goal position - hip EXTENDED (0-10° extension), externally rotated 30-45°, slightly adducted. Assistant holds leg or use positioner. Gravity assists with retraction.
Retractor Placement: (1) Lateral retractor (protects gluteus medius/TFL), (2) Medial retractor (elevates iliopsoas), (3) Anterior retractor (retracts vastus lateralis). Specialized bent femoral elevators crucial for exposure.
Proximal Femur Visualization: Must see greater trochanter, femoral neck osteotomy site, and proximal femoral shaft. If visualization inadequate - release more capsule, adjust leg position, consider different retractors. DO NOT PROCEED if cannot see proximal femur clearly.
Exam Pearl
Learning Curve Reality: Femoral exposure is most technically challenging DAA step. Requires: (1) Adequate table configuration allowing extension, (2) Complete capsular release, (3) Correct leg positioning, (4) Appropriate retractors, (5) Experience. Learning curve 30-100 cases. Periprosthetic fracture rate 2-5% early in learning curve, reduces to 0.5-1% with experience. Know when to abort to lateral/posterior approach if unsafe.
Dangers - Femoral Exposure (Highest Risk Step)
- Periprosthetic femur fracture (most serious DAA complication, 2-5% learning curve, <1% experienced)
- Abductor injury with lateral retractor (gluteus medius avulsion from GT)
- Vastus lateralis injury with anterior retractor
- Inability to visualize femur (abort to different approach if unsafe - patient safety priority)
Step 10: Femoral Canal Preparation
Canal Opening: Use femoral elevator/canal finder to locate canal entry. Entry point medial aspect of greater trochanter in line with femoral shaft axis.
Box Chisel: Remove calcar bone with box chisel to achieve proper varus-valgus alignment and prepare for broach entry. Remove sufficient medial bone for broach to sit in neutral-to-slight-valgus (avoid varus position).
Broaching: Start with small broach (typically 2-4 sizes smaller than templated). Progressive broaching with increasing sizes. Broach orientation: 10-15° anteversion (align with femoral neck version), slight valgus alignment.
End Point: Broach until achieving "cortical chatter" - palpable vibration transmitted through broach handle indicating metaphyseal cortical contact. Broach should seat to planned depth (typically calcar fully contacted).
Assessment: Final broach should be stable without excessive impaction force. Assess broach depth, version (10-15° anteversion), varus-valgus alignment (neutral to slight valgus). Check for cortical perforation (feel for false passage, check medial/lateral cortices).
Exam Pearl
Broaching Technique: "Broach until it chatters" - cortical chatter indicates good metaphyseal fit (essential for cementless stem stability). Entry point = medial aspect GT, alignment = slight valgus (NOT varus), version = 10-15° anteversion. Broach depth determines final stem position. Vancouver fracture risk highest during broaching - gentle progressive impaction, check for cortical perforation, adequate bone quality assessment.
Dangers - Broaching
- Periprosthetic fracture (most common during broaching, 2-5% in learning curve)
- Varus malalignment (subsidence, thigh pain, early loosening)
- Cortical perforation (weakens bone, stress riser for fracture)
- Undersized stem (subsidence, loosening, instability)
- Oversized stem (fracture during insertion)
Step 11: Trial Reduction and Assessment
Trial Assembly: Insert trial stem matching final broach size. Insert trial head (start with +0 or templated neck length).
Hip Reduction: Reduce hip by bringing femur anterior and flexing while stabilizing pelvis. Should reduce with gentle force (difficult reduction suggests oversized components or malposition).
Stability Testing: Test through full ROM with specific attention to at-risk positions:
- Flexion 110-120° + adduction + internal rotation (posterior dislocation position)
- Extension + external rotation (anterior dislocation position - rare in DAA)
- Hip should be STABLE without excessive reduction force
Leg Length Assessment: DAA advantage - supine position allows accurate comparison. Measure from fixed pelvic landmark (ASIS, iliac crest) to medial malleolus bilaterally. Compare with pre-operative measurement and contralateral side. Target: equal or 5mm lengthening (patients tolerate slight lengthening better than shortening).
Offset Assessment: Adequate offset = proper abductor tension. Test: anterior superior iliac spine to greater trochanter distance should approximate contralateral side or match templating.
ROM Assessment: Check ROM - flexion 110-120°, extension 10-20°, abduction 45°, adduction 30°, IR/ER 45°. Assess for impingement (bone-on-bone or prosthetic impingement).
Adjustments: If unstable/incorrect length/inadequate offset - adjust head size/neck length (increases/decreases offset and length), change cup position if necessary (rare), downsize stem if excessive offset.
Exam Pearl
Trial Reduction Critical Assessment: Four priorities: (1) STABILITY - test in flexion/adduction/IR (posterior risk position), should be stable without excessive reduction force. (2) LEG LENGTH - supine advantage for accurate assessment, target equal or +5mm. (3) OFFSET - adequate abductor tension, match templating. (4) ROM - no impingement. Adjust with head size/neck length. DAA dislocation rate 0.5-2% (lower than posterior 2-5%) due to posterior capsule preservation.
Dangers - Trial Reduction
- Leg length discrepancy (most common patient complaint and medicolegal issue)
- Instability (inadequate assessment leads to postop dislocation)
- Inadequate offset (limp, abductor fatigue, impingement)
- Unrecognized impingement (squeaking, accelerated wear, instability)
Step 12: Final Component Insertion
Trial Disassembly: Dislocate trial components. Remove trial head, extract trial stem with slap hammer.
Liner Insertion: Insert definitive liner into acetabular shell. Most liners use Morse taper - must hear loud "SNAP" or "CLICK" confirming full seating. Some systems have secondary locking mechanism - ensure engaged. Verify liner fully seated (no gap between liner and shell).
Femoral Canal Final Prep: Clean canal thoroughly with suction and brush. Irrigate canal. Dry with suction and gauze/swabs (critical for cementless fixation - moisture prevents bone ingrowth). Inspect canal for loose bone fragments.
Stem Insertion: Insert final stem using stem inserter aligned to planned version (10-15° anteversion). Progressive impaction with mallet. End point: stem seated to level 1-2mm PROUD of final broach position (subsides ~1-2mm during final impaction). Check seating against calcar landmark.
Head Application: CRITICAL for preventing taper corrosion. (1) Clean head bore and stem taper with gauze (remove ALL debris, fluid). (2) Ensure completely DRY. (3) Align head to planned version. (4) Firmly impact head onto taper - 12mm taper requires 5-6 firm strikes, larger tapers require more impacts. Inadequate impaction = taper micromotion = fretting corrosion = trunnionosis.
Exam Pearl
Component Assembly Technique: Liner seating MUST achieve audible SNAP (Morse taper engagement) - unseated liner causes dislocation or liner fracture. Stem typically seats 1-2mm PROUD of broach (subsides during impaction). Head-taper junction CRITICAL - clean both surfaces, ensure DRY, FIRM impaction (12mm taper = 5-6 strikes minimum). Inadequate head impaction causes taper fretting corrosion (trunnionosis) leading to ALTR or dissociation.
Dangers - Final Components
- Liner malseating (catastrophic - dislocation or liner fracture)
- Stem subsidence (inadequate impaction or undersized stem)
- Periprosthetic fracture during final stem impaction
- Head malseating (inadequate taper engagement = corrosion, ALTR, dissociation)
Step 13: Final Reduction and Comprehensive Assessment
Hip Reduction: Reduce hip by bringing femur anterior with traction and flexing. Should reduce with gentle manipulation (resistance suggests oversizing or malposition).
Range of Motion Testing: Perform complete ROM assessment:
- Flexion 110-120°
- Extension 10-20°
- Abduction 45°
- Adduction 30°
- Internal rotation 45° (in flexion and extension)
- External rotation 45° (in flexion and extension)
Stability Testing: Critical final check - test in all at-risk positions:
- Combined flexion + adduction + IR (posterior dislocation - most common position)
- Extension + external rotation (anterior dislocation - rare in DAA)
- Pure flexion >120° (anterior impingement check)
- Pure extension (posterior impingement check)
Clinical Measurements: Final leg length assessment - measure bilaterally from fixed pelvic point to medial malleolus. Compare with pre-operative measurements. Document any discrepancy.
Imaging Confirmation: Intra-operative fluoroscopy (if available) - AP pelvis confirms cup position (inclination, no protrusion), lateral confirms version. AP femur confirms stem position, rules out fracture.
Impingement Assessment: Bring hip through combined movements looking for bone-on-bone or prosthetic impingement. Impingement causes squeaking, accelerated wear, instability.
Exam Pearl
Final Stability Gold Standard: DAA dislocation rate 0.5-2% (superior to posterior approach 2-5%) due to posterior capsule and short external rotator preservation. However, MUST verify stability intra-operatively. Test combined flexion/adduction/IR with axial load (posterior dislocation position) - hip should remain stable without excessive force. Extension/ER testing less critical in DAA (anterior dislocation rare). Document ROM and stability in operative note.
Dangers - Final Assessment
- Inadequate stability testing (dislocation in recovery room or during mobilization)
- Unrecognized leg length discrepancy (patient dissatisfaction, gait abnormality, medicolegal)
- Missed fracture (if not using fluoroscopy)
- Unrecognized impingement (long-term squeaking, wear, or instability)
Step 14: Wound Closure
Copious Irrigation: Irrigate wound with minimum 6-9 liters pulsatile lavage (reduces infection risk). Include deep intervals, capsular space, superficial tissues.
Capsular Management: Most surgeons perform NO capsular repair or minimal repair in DAA (posterior capsule intact provides stability). If repairing, use absorbable suture to close anterior capsule.
Fascial Closure: Close fascia between TFL and sartorius with interrupted or running absorbable suture (#1 Vicryl or equivalent). Ensure adequate strength (prevents hernia or muscle dehiscence).
Subcutaneous Closure: Close subcutaneous layer with absorbable suture (2-0 or 3-0 Vicryl) to eliminate dead space and reduce seroma/hematoma.
Skin Closure: Surgeon preference - staples (faster, traditional) or subcuticular absorbable suture (better cosmesis). Ensure skin edges well-approximated.
Drainage: CONTROVERSIAL - most current evidence shows drains provide NO benefit and may INCREASE infection risk. Consider drain only if: (1) Significant oozing despite hemostasis, (2) Large dead space, (3) Anticoagulated patient with high bleeding risk. If using drain, remove within 24 hours.
Dressing: Absorbent dressing, consider negative pressure wound therapy if high risk (obese, diabetic, immunosuppressed).
Exam Pearl
Drain Controversy: Multiple RCTs and meta-analyses show drains do NOT reduce hematoma or infection in primary THR and may INCREASE infection risk (bacterial retrograde migration). Current best practice: NO ROUTINE DRAINS. Reserved for exceptional circumstances (ongoing ooze despite hemostasis, large dead space). If drain used, remove <24 hours. AOANJRR data confirms infection rate with drains numerically higher.
Dangers - Closure
- Inadequate hemostasis (hematoma formation, increased infection risk)
- Weak fascial closure (muscle dehiscence, hernia)
- Wound dehiscence (especially in obese patients, diabetics)
- Drain-related infection if drain retained >24 hours
Step 15: Postoperative Protocol and Follow-up
Day 0 (Day of Surgery)
- Mobilize with physiotherapy same day (early mobilization reduces DVT, improves outcomes)
- Weight bearing as tolerated (WBAT) - NO restrictions
- NO HIP PRECAUTIONS (key DAA advantage - posterior approach requires 6 weeks avoiding flexion >90°, adduction, IR)
- Gait training with walking frame or crutches
- DVT prophylaxis per protocol (LMWH, DOAC, or mechanical)
Day 1-2
- Continue mobilization - stairs training if needed
- Discharge home if medically stable, adequate mobility, safe home environment
- Walking aids: frame or crutches initially, progress to stick as able
Week 2
- Wound check in clinic or community
- Suture/staple removal
- Progress from frame to crutches to stick as mobility improves
Week 6
- X-ray check: AP pelvis, lateral hip
- Assess component position, rule out fracture, check for radiolucent lines
- Clinical assessment: wound, ROM, gait, leg length, stability
- Progress activity - return to driving if safe (right hip - ensure can perform emergency stop)
Month 3
- Return to low-impact sports (golf, swimming, cycling)
- Return to work for most patients (sedentary/light duties)
Month 6
- Return to impact sports if desired (running, tennis - controversial, not universally recommended)
- Heavy manual work
Year 1 and Beyond
- Annual review with X-ray (years 1, 3, 5, 10, then every 5 years)
- AOANJRR data: 10-year revision rate primary OA THR ~5%
- Monitor for wear, loosening, osteolysis, infection
DVT Prophylaxis: Extended duration per guidelines - LMWH (enoxaparin 40mg daily) or DOAC (rivaroxaban 10mg daily, apixaban 2.5mg BD) for 35 days post-discharge (ACCP guidelines). Combine with mechanical prophylaxis (TED stockings, pneumatic compression).
Exam Pearl
DAA Postoperative Advantage: NO HIP PRECAUTIONS - immediate WBAT, no movement restrictions (posterior approach requires 6 weeks avoiding: flexion >90°, adduction past midline, IR in extension). This is major DAA advantage - allows faster rehabilitation, easier ADLs (putting on shoes/socks, getting in/out of car, using toilet). Studies show faster early recovery though long-term outcomes equivalent. Lower dislocation rate (0.5-2% vs 2-5% posterior).
Post-operative Complications
- Early dislocation (0.5-2% in DAA) - usually in recovery or first mobilization
- DVT/PE without adequate prophylaxis (1-2% with prophylaxis)
- Periprosthetic fracture during early mobilization (especially if intra-operative fracture missed)
- Infection (0.5-1% in primary THR)
- Wound complications (hematoma, dehiscence, delayed healing - higher in obese, diabetic)