The library has limited specific content on ACL rehab protocols and FFD correction. I'll now synthesize a comprehensive note drawing from what was retrieved plus established clinical knowledge.
ADDENDUM: FFD Correction + ACL Tear
(Appended to Right Knee OA + Left Hip Hike Notes)
FIXED FLEXION DEFORMITY (FFD) — Right Knee
What It Is
A fixed flexion deformity (FFD) means the knee cannot be passively extended to neutral (0°). In knee OA, it commonly results from:
- Posterior capsule contracture
- Hamstring tightness/spasm
- Chronic effusion (joint held in ~30° — position of maximum intra-articular volume)
- Quadriceps inhibition with compensatory flexion posture
- Pain-avoidance holding pattern
Assessment of FFD
| Assessment Item | Method |
|---|
| Degree of FFD | Supine: note angle at which knee rests without passive pressure; measure with goniometer (e.g. 10°, 15°, 20° FFD) |
| Passive extension | Apply gentle sustained overpressure — note end-feel (capsular = hard; muscular = springy) |
| Posterior capsule tightness | Prone knee extension test (compare bilateral) |
| Hamstring length | Straight leg raise (SLR), popliteal angle |
| Hip flexion contracture | Thomas test — hip flexion contracture causes apparent knee FFD via anterior pelvic tilt |
| Effusion | Sweep test, ballottement — effusion perpetuates flexion posture |
| Functional impact | Stair descent, walking speed, energy expenditure (FFD increases metabolic cost of walking) |
PT Management — FFD Correction
1. Effusion Control (if present — first priority)
- RICE (Rest, Ice, Compression, Elevation) for acute flare
- Electrotherapy: TENS for pain, interferential therapy to reduce effusion
- Manual lymphatic drainage / effleurage
- Compression bandaging
- Reduce provocative activities temporarily
2. Extension Stretching (Passive & Active)
- Prone lying extension: Patient lies prone with knee hanging off bed edge — gravity provides gentle sustained stretch; progress with small ankle weight (0.5–1 kg)
- Heel prop in supine: Place bolster/roll under heel (not under knee) → gravity allows passive knee extension; hold 10–20 min, 2–3×/day
- Low-load prolonged stretch (LLPS): Most effective for capsular contracture — sustained low load over 20–30 minutes preferred over high-load brief stretches
- Dynamic splinting / serial casting: For FFD > 15–20° not responding to exercise — static progressive or dynamic extension splint worn for periods through day; serial casting in more severe/chronic cases
3. Posterior Capsule & Hamstring Stretching
- Supine hamstring stretch (towel/strap assisted)
- Standing hamstring stretch (knee straight, hip flexed)
- Gastrocnemius stretch (contributes to knee flexion posture)
- Posterior capsule mobilization: Posterior glide of tibia on femur (accessory joint mobilization)
4. Joint Mobilization
- Posterior tibial glide in near-extension range to improve terminal extension
- Patellofemoral superior glide (restricted superior glide limits full knee extension)
- Sustained end-range mobilization into extension
5. Muscle Re-education
- Terminal knee extension (TKE): Using resistance band fixed behind knee, patient actively extends from 20° to 0° → targets VMO in terminal range
- Prone knee extension with quad contraction: Contract quads at end of prone hang
- Vastus Medialis Oblique (VMO) activation: Essential for active extension recovery
6. Neuromuscular Electrical Stimulation (NMES)
- Applied to quadriceps to augment voluntary activation
- Reduces quadriceps inhibition from effusion/pain
- Use in conjunction with active exercise
7. Functional Progression
- Walking re-education — ensure heel strike and terminal knee extension in stance
- Stair training — emphasize full extension at top of step
- Avoid prolonged sitting in flexion (>90°) — advise frequent position changes
Goals for FFD Correction:
- < 5° FFD: conservative PT (4–8 weeks intensive)
- 5–15° FFD: aggressive PT + splinting (8–12 weeks)
-
20° FFD or bony block: orthopaedic referral (posterior capsular release, osteotomy considerations)
ACL TEAR — Assessment & Management
Background (in context of this patient)
ACL tear + right knee OA is a common combined pathology — chronic ACL insufficiency is a risk factor for OA progression. Establish whether this is:
- Acute ACL tear (recent injury — haemarthrosis, significant instability)
- Chronic ACL deficiency (longstanding, with adaptive strategies)
- Post-ACL reconstruction (rehab protocol)
Assessment
Subjective
- Mechanism: Non-contact pivot/twist, valgus collapse, hyperextension, or contact
- Acute: "Pop," immediate haemarthrosis (within 2 hours), inability to continue activity
- Chronic: Giving way with pivoting, cutting, deceleration
- Previous surgery or prior ACL injury
Special Tests
| Test | Technique | Positive Finding |
|---|
| Lachman test (most sensitive — 80–99%) | Knee at 20–30° flexion; stabilize femur, anterior draw on tibia | Excessive anterior translation + absent/soft endpoint |
| Anterior Drawer test | Knee at 90°; anterior force on proximal tibia | Anterior translation > 5 mm |
| Pivot Shift test (most specific) | IR tibia + valgus stress during flexion-extension | Clunk/pivot at ~30° flexion → ACL insufficiency with rotatory instability |
| KT-1000 arthrometer | Objective side-to-side measurement | > 3 mm difference = significant laxity |
Imaging
- MRI: Investigation of choice — confirms ACL tear, assesses meniscal/chondral/collateral damage (associated injuries very common — "terrible triad": ACL + MCL + medial meniscus)
- X-ray: Exclude fracture; Segond fracture (lateral tibial plateau avulsion) = pathognomonic of ACL injury
- Joint line tenderness + Lachman positive + MRI = standard diagnostic pathway
Functional Assessment
- Single-leg squat quality (dynamic valgus — indicates poor neuromuscular control)
- Single-leg hop tests: Single hop, triple hop, crossover hop (for chronic/post-surgical)
- Y-Balance test / Star Excursion Balance Test
- Quadriceps and hamstring strength (dynamometry) — H:Q ratio target > 0.6
PT Management — ACL Tear
Phase 1: Acute / Pre-operative (0–2 weeks)
Goals: Reduce pain/swelling, restore ROM, prevent quadriceps atrophy
- RICE — ice 15–20 min every 2 hours, compression, elevation
- Crutches — partial weight bearing as tolerated
- Effusion management (as per FFD section above)
- Quadriceps activation: Quad sets, SLR in brace — critical to prevent inhibition
- ROM: Heel slides for knee flexion; terminal knee extension (TKE) for extension
- Gait re-education with crutches
- Educate on surgical vs. conservative management options
Conservative Management (Non-surgical — selected patients)
Indicated for: Older/sedentary patients, partial tears, low-demand activity level, or patient preference
- Structured neuromuscular training program (e.g., MOON, KANON protocols)
- Emphasis on: Quadriceps strengthening, hamstring strengthening, neuromuscular control, proprioception
- Functional bracing for sports/instability episodes
- Activity modification — avoid pivoting/cutting sports without reconstruction
- Note: In this patient's context (right knee OA + ACL), conservative management with structured PT is a reasonable first approach especially if activity demands are low
Surgical Management — ACL Reconstruction (ACLR)
Indicated for: Young/active patients, combined injuries, persistent instability, failed conservative management
- Most common graft: Bone-patellar tendon-bone (BPTB) or hamstring autograft
- Surgery timing: Wait until full ROM restored and swelling resolved (reduces risk of arthrofibrosis)
- Prehabilitation ("prehab") before surgery strongly improves post-op outcomes
Post-ACLR Rehabilitation Phases
Phase 1 — Protection (0–2 weeks)
- Crutches, brace locked in extension for ambulation
- Goals: Control swelling, achieve 0–90° ROM, quad activation
- Exercises: Quad sets, SLR (all planes), heel props, ankle pumps, NMES to quads
- Avoid: Hamstring loading (graft protection — hamstring graft)
- Cryotherapy after exercise
Phase 2 — Early Strengthening (2–6 weeks)
- Wean crutches as quad control adequate
- ROM target: 0–120°+ by week 6
- Closed Kinetic Chain (CKC) exercises — safer for graft:
- Mini squats, leg press (0–60°), step-ups/downs, stationary cycling
- Terminal knee extension with band
- Open Kinetic Chain (OKC): Quad extension 90–40° range (avoids anterior shear at 0–40°); initiate week 4–6 depending on protocol
- Hamstring curls: Start week 4+ (graft-dependent)
- Proprioception: Single-leg balance, wobble board (eyes open → closed)
- Pool walking / hydrotherapy
Phase 3 — Advanced Strengthening (6–12 weeks)
- Full ROM expected
- Progressive loading: Leg press full range, squats, lunges, step machine
- Neuromuscular training: Single-leg squat, lateral band walks, perturbation training
- Low-impact cardio: Cycling, swimming, elliptical
- Gait normalization — eliminate antalgic pattern
Phase 4 — Return to Running (3–4 months)
- Criteria-based (not time-based):
-
80% limb symmetry index (LSI) on quad/hamstring strength
- Good single-leg squat quality (no dynamic valgus)
- Normal gait
- Jogging program (walk-jog intervals), progress to running
- Agility ladder, straight-line cutting
Phase 5 — Return to Sport (6–9+ months)
- Criteria (all must be met):
- LSI ≥ 90% on hop tests (single, triple, crossover hop)
- LSI ≥ 90% on isokinetic quad/hamstring strength
- Psychological readiness (ACL-RSI questionnaire)
- No pain/swelling with loading
- Sport-specific drills: Pivoting, cutting, change of direction
- ACL injury prevention program (FIFA 11+, PEP) before return
Integration with Right Knee OA + Hip Hike
| Interaction | Management Consideration |
|---|
| ACL laxity + OA | ACL insufficiency accelerates OA progression — address both simultaneously |
| FFD + ACL rehab | Restoring full knee extension is Phase 1 goal of ACLR rehab — FFD correction protocols above apply directly |
| Hip hike + ACL | Poor hip/core control = dynamic valgus during ACL rehab → re-injury risk; glut med strengthening is mandatory in ACL return-to-sport |
| OA + ACLR surgery | Post-op OA management continues: weight management, quadriceps strengthening, aquatic therapy |
| Gait retraining | Correct hip hike AND quad avoidance pattern before return to sport |
Red Flags / Referral
| Finding | Action |
|---|
| Haemarthrosis + ACL + > 1 structure injured | Urgent orthopaedic referral (within 1–2 weeks) |
| FFD > 20° not improving in 6–8 weeks | Orthopaedic review — surgical release |
| Locking (not pseudolocking) | MRI + orthopaedic referral — meniscal bucket-handle tear |
| Neurovascular compromise post-injury | Emergency referral |
| Failed conservative ACL at 3 months | Surgical reconstruction discussion |
Sources: Miller's Review of Orthopaedics 9th Ed, p. 354–355; Goldman-Cecil Medicine, Chapter 241; Swanson's Family Medicine Review, Chapter 167; supplemented by established clinical PT protocols (MOON, KANON, FIFA 11+)