2.2 Lower Extremity Conditions & Post-Op Protocols
Key Takeaways
- Posterior total hip arthroplasty (THA) precautions: no hip flexion past 90 degrees, no adduction past midline, no internal rotation; anterolateral approach restricts extension, external rotation, and adduction.
- Total knee arthroplasty (TKA) ROM benchmarks: 90 degrees flexion by week 2, 110-115 degrees by week 6, and full active extension to 0 degrees as early as possible to prevent flexion contracture.
- Meniscus repair generally requires non-weight-bearing (NWB) to toe-touch weight-bearing (TTWB) for 4-6 weeks with brace-limited flexion; meniscectomy (partial) is weight-bearing as tolerated (WBAT) immediately.
- Anterior cruciate ligament reconstruction (ACL-R) progresses in phases — protective (weeks 0-2), motion/strength (weeks 2-12), running (months 3-5), and return-to-sport (months 6-9+) with limb symmetry index (LSI) >90%.
- Ankle sprain grades: I (microtear, full weight-bearing (FWB) early), II (partial tear, brace + protected weight-bearing (PWB)), III (complete tear, immobilization 2-4 weeks before progressive loading).
Hip Conditions
Total Hip Arthroplasty (THA) Precautions by Approach
The surgeon's surgical approach dictates which motions disrupt the repair. Memorize both common patterns; the NPTE-PTA tests them frequently.
| Approach | Forbidden Motions (Typical 6-12 weeks) | Common PTA Modifications |
|---|---|---|
| Posterior (posterolateral) | No hip flexion >90 degrees; no adduction past midline; no internal rotation (IR) | Use elevated toilet seat, abduction pillow when supine, long-handled reachers; avoid low chairs and crossing legs |
| Anterolateral (direct anterior) | No combined hip extension + external rotation (ER); avoid adduction past midline | Limit aggressive backward stepping and bridging-into-extension early |
Hip osteoarthritis (OA) without surgery is managed with progressive resistance, aquatic exercise, gait training with assistive device if antalgic gait, and education on activity pacing.
Knee Conditions
Total Knee Arthroplasty (TKA)
The biggest enemy of TKA outcome is a flexion contracture. Recovering full extension to 0 degrees is prioritized equally with restoring flexion.
| Week | Flexion Goal | Extension Goal | Typical Intervention |
|---|---|---|---|
| 1 | 70-90 degrees | -5 to 0 degrees | Heel slides, prone hangs, quad sets, ankle pumps |
| 2-3 | 90-105 degrees | 0 degrees | Stationary bike (partial revolution then full), short-arc quad |
| 4-6 | 110-115 degrees | 0 degrees | Step-ups, mini-squats, terminal knee extension |
| 8-12 | 115-125 degrees | 0 degrees | Progressive resistance, balance, return to community ambulation |
ACL Reconstruction (ACL-R)
Phase-based with criterion-based progression:
- Phase I (0-2 weeks): Protect graft; full passive extension; quad activation; weight-bearing as tolerated (WBAT) with brace locked at 0 degrees per surgeon.
- Phase II (2-12 weeks): ROM restoration, closed-chain strengthening (mini-squats, leg press in safe arc), proprioception. Avoid open-chain knee extension 0-30 degrees through ~12 weeks (anterior shear on graft).
- Phase III (3-5 months): Running progression once 70-80% quad strength and pain-free single-leg squat.
- Phase IV (6-9+ months): Plyometrics, sport-specific cutting; return-to-sport requires limb symmetry index (LSI) >90% on strength and hop testing per current evidence.
Meniscus Repair vs Meniscectomy
This is a high-yield NPTE-PTA distinction.
| Procedure | Weight-Bearing | ROM | Return-to-Activity |
|---|---|---|---|
| Partial meniscectomy | WBAT immediately | Full as tolerated | 4-6 weeks |
| Meniscus repair | NWB or TTWB 4-6 weeks; brace limits flexion (often 0-90 degrees) | Progress flexion gradually; avoid deep flexion under load 4 months | 4-6 months |
Ankle and Foot
Lateral Ankle Sprain Grading
| Grade | Tissue State | Weight-Bearing | Typical PTA Program |
|---|---|---|---|
| I | Stretched ligament, no laxity | FWB with mild support | Ice, compression, early ROM, isometrics |
| II | Partial tear, mild laxity | PWB with brace 1-2 weeks | Progressive ROM, proprioception, peroneal strengthening |
| III | Complete tear, gross laxity | Immobilize 2-4 weeks | Slow loading, brace, balance progression, sport drills |
Plantar Fasciitis
Morning heel pain with first steps and after rest. PTA-implemented care: plantar fascia stretching, gastrocnemius-soleus stretching, eccentric heel drops, ice massage with frozen bottle, night splints, low-Dye taping, and footwear education.
Achilles Tendon Repair
Accelerated functional rehab now favors early protected weight-bearing in a controlled ankle motion (CAM) boot with heel wedges, weaned over 6-8 weeks. PTAs implement progressive AROM, isometrics, then concentric and finally eccentric loading; running typically resumes 4-6 months post-op.
A patient is 3 days post posterior total hip arthroplasty (THA) and asks the PTA for help putting on socks while sitting on the edge of the bed. Which PTA action BEST protects the surgical hip?
Two patients are on the PTA's caseload after knee surgery yesterday — Patient A had a partial medial meniscectomy and Patient B had a medial meniscus repair. Both ask to ambulate to the bathroom. What is the MOST appropriate PTA response based on standard protocols?