Total Hip Replacement

One wrong leg position after a total hip replacement can dislocate the prosthesis in seconds — knowing which movements to prevent depends entirely on the surgical approach used.

After total hip replacement (arthroplasty), the primary nursing goal is preventing prosthetic dislocation while promoting mobility. The posterior approach (most common) requires avoiding hip flexion beyond 90 degrees, adduction past midline, and internal rotation — collectively remembered as the 'don't cross, don't bend too far, don't twist in' rules. An abduction pillow or wedge is placed between the legs at all times in bed. The patient uses a raised toilet seat, avoids low chairs, and does not bend forward to tie shoes. With an anterior approach, precautions are less restrictive but still include avoiding hyperextension and external rotation. Assess the operative leg each shift: neurovascular checks (circulation, sensation, movement distal to the site), wound drainage via Hemovac or Jackson-Pratt drain (expect 200–500 mL in the first 24 hours, decreasing thereafter), and leg length and alignment. Signs of dislocation include sudden severe pain, affected leg appears shorter and externally or internally rotated (depending on approach), and the patient cannot bear weight. Notify the provider immediately — do not attempt to reposition the joint. DVT prophylaxis is critical: administer prescribed anticoagulants (enoxaparin or warfarin), apply sequential compression devices, and encourage ankle pumps and early ambulation, typically by postop day 1. Monitor for bleeding complications when anticoagulation overlaps with surgical drainage.

Key Distinctions

Don't confuse posterior approach precautions (no flexion >90°, no adduction, no internal rotation) with anterior approach precautions (no hyperextension, no external rotation) — the restricted movements are nearly opposite. Students mix up dislocation signs with fracture signs: dislocation produces acute pain with leg shortening and rotation without trauma, while a periprosthetic fracture typically follows a fall. The abduction pillow prevents adduction — it keeps legs apart, not together.

Clinical Pearl

Posterior approach: 'Don't cross your legs, don't bend past 90, don't turn your toes in.' If the leg suddenly looks shorter and rotated after surgery, think dislocation — not fracture.