7.4 Orthopedic Care, Immobilization & Mobility

Casts: Assessment and Care

Casts immobilize fractures while they heal. Plaster casts are heavier, moldable, and take 24 to 72 hours to dry; fiberglass casts are light, water-resistant (the lining is not), and dry in 10 to 15 minutes.

Care of a fresh cast:

• Handle a wet plaster cast with the palms of the hands, never the fingertips — finger pressure dents the cast and creates pressure points that cause skin breakdown
• Support the cast on pillows; elevate the limb above heart level for the first 24 to 48 hours to reduce swelling, and apply ice bags to the sides of the cast (not on top) intermittently
• Leave the cast exposed to air while drying; do not cover it or use a hair dryer on hot settings (cool air only, for itching)
• Once dry, "petal" rough edges with adhesive strips to protect skin
• Perform frequent neurovascular checks (color, warmth, capillary refill, pulses, sensation, movement, pain) distal to the cast, comparing sides

Patient teaching: keep the cast dry (cover with plastic for bathing), never insert objects (pencils, coat hangers, powder) inside to scratch — this abrades skin and seeds infection; and report danger signs immediately: pain unrelieved by analgesia, numbness or tingling, burning under the cast, a "hot spot" (localized warmth suggesting pressure injury or infection), drainage or foul odor (note and circle any drainage with date and time), and fingers or toes that are pale, blue, cold, or swollen. Neurovascular compromise requires cast loosening or bivalving; compartment syndrome requires fasciotomy.

Traction

Traction applies pulling force to align and immobilize fractures, reduce muscle spasm, and correct deformity.

Universal traction rules: weights must hang freely and never rest on the floor or bed; ropes stay centered in the pulleys; the patient remains in good body alignment; and skeletal traction is continuous — never remove or lift the weights without a provider's order. Inspect pressure points (heels, sacrum, elbows) and encourage deep breathing to prevent pneumonia.

Total Hip Replacement (Arthroplasty)

Postoperative priorities after total hip replacement (THR): frequent neurovascular checks of the operative leg, pain control, venous thromboembolism prophylaxis (anticoagulants such as enoxaparin or rivaroxaban plus sequential compression devices), incentive spirometry, wound monitoring, and early mobilization — most patients bear weight and walk with assistance on the day of surgery or postoperative day 1.

Dislocation is the feared early complication, so hip precautions depend on the surgical approach. The posterior approach (most commonly tested) requires avoiding:

• Hip flexion greater than 90 degrees — no low chairs, no bending to tie shoes, use an elevated toilet seat
• Adduction past midline — no crossing the legs or ankles; maintain an abduction pillow or wedge between the legs in bed, and sleep with a pillow between the knees
• Internal rotation — no pivoting on the operative leg; turn the whole body when changing direction; avoid hip flexion with internal rotation and adduction (getting out of a low car seat is the classic violation)

The anterior approach carries fewer restrictions but avoids excessive extension and external rotation. Teach the signs of dislocation to report: sudden severe hip pain, a "popping" sensation, shortening of the leg with external rotation, and inability to move the leg. Also teach lifelong precautions: report infection signs promptly, tell dentists about the prosthesis (prophylaxis per current guidance), and expect to trigger metal detectors.

Total Knee Replacement and CPM

After total knee replacement (TKR), priorities mirror THR: neurovascular checks (peroneal nerve injury causes footdrop — watch for inability to dorsiflex), anticoagulation, ice and elevation for swelling, and aggressive pain control so the patient can participate in therapy. Range of motion is the central goal; many surgeons order a continuous passive motion (CPM) machine, which flexes and extends the knee through a prescribed arc (for example, starting at 0-30 degrees and advancing daily) to prevent scar tissue and stiffness. When applying CPM: align the machine's joint with the patient's knee, support the leg, document the degrees and hours of use, and keep the machine off during meals and toileting. Weight bearing is typically as tolerated with a walker; the target is roughly 90 degrees of flexion for functional sitting and stairs.

Amputation Care

Postoperative care after lower-limb amputation centers on the residual limb (the preferred term over "stump"):

• Hemorrhage watch: keep a large tourniquet at the bedside in the early postoperative period for severe stump bleeding — apply it and call for help
• Positioning: elevate the limb on a pillow for the first 24 to 48 hours only, then keep it flat; prolonged elevation or a pillow under the knee promotes flexion contracture. Place the patient prone for 20-30 minutes several times a day to stretch the hip flexors
• Limb shaping: once the incision heals, wrap with elastic bandages in a figure-8 pattern (never circular, which constricts), rewrapping several times a day to shape the limb for prosthesis fitting
• Skin care: wash with mild soap and water, dry thoroughly, inspect daily with a mirror, avoid lotions unless directed, and report redness or breakdown
• Desensitization: gentle massage, tapping, and rubbing the limb with progressively coarser textures prepares it for weight bearing in a prosthesis

Phantom limb sensation — the feeling that the limb is still present, including itching or tingling — is normal and not pathologic; acknowledge it rather than dismissing it. Phantom limb pain is real, burning or cramping pain in the missing limb and deserves treatment: medications such as gabapentin or tricyclic antidepressants, mirror therapy, transcutaneous electrical nerve stimulation (TENS), and desensitization. Support grief and body-image adjustment, and refer to peer support and rehabilitation early.

Assistive Devices and Gait

Match the device to the deficit and teach correct technique:

• Walker: provides the most stability for bilateral weakness or poor balance. Sequence: advance the walker, step forward with the weak leg, then bring the strong leg through. The walker should reach wrist height with elbows slightly flexed.
• Cane: hold the cane on the strong (unaffected) side — this widens the base and offloads the weak side. Advance the cane together with the weak leg, then step through with the strong leg. On stairs: "up with the good, down with the bad" — the strong leg leads going up, and the cane with the weak leg leads going down.
• Crutches: fit with 2-3 finger widths between the axilla and the crutch top; weight is borne on the hands, never the axilla — pressure there damages the radial nerve and brachial plexus (crutch palsy: wrist drop, numbness). Common gaits: four-point (slow, stable, for bilateral weakness), two-point (faster, partial weight bearing), three-point (one leg non-weight bearing — advance both crutches with the weak leg, then the strong leg), and swing-through (spinal cord injury with leg braces). On stairs without a railing, follow the same up-with-the-good rule.

Safe Transfers and Mobility Progression

• Always transfer the patient toward the strong side; use a gait belt (never grab under the arms — risk of shoulder injury and skin shear), block the patient's weak knee with your own, and have the patient pivot on the strong leg
• Lock wheelchairs and beds, remove throw rugs, and ensure nonskid footwear before any transfer
• Progress mobility in stages: dangling at the bedside (feet down, assess for orthostatic hypotension — dizziness, drop in blood pressure) before standing, then standing balance, then ambulation with the least restrictive device that is safe
• After prolonged bed rest, raise the head gradually and pause between positions; if the patient becomes dizzy or pale, return them to a safe seated or lying position
• Document distance, device, assistance level, tolerance, and any near-falls; fall-risk reassessment follows every status change or new sedating medication