Overview
This lecture covers anterior and posterior knee injuries, focusing on movement strategies, injury mechanisms, evaluation, and rehabilitation, including practical treatment strategies and movement analysis.
Anterior Knee Injuries and Movement Strategies
- Anterior knee pain arises from primary (local) and secondary (kinetic chain) impairments.
- Overutilizing quadriceps (knee strategy) and underutilizing posterior chain can cause or worsen anterior knee injuries.
- Knee strategy = dominant knee flexion, high quad demand, and increased anterior knee load.
- Hip strategy = dominant hip flexion, higher demand on the glutes and hamstrings.
- Optimal movement pattern shows equal hip and knee flexion.
- Faulty knee strategy often seen in athletes (e.g., jumps, squats), leading to overuse injuries like patellar tendinopathy, Osgood-Schlatter, and quad strains.
- Symmetrical hip and tibia angles during flexion indicate balanced movement.
Evaluation and Correction of Faulty Patterns
- Movement analysis (squat, gait) helps identify kinetic chain dysfunctions missed by isolated knee exams.
- Treat knee strategy by improving hip mobility, quad and IT band flexibility, and posterior chain strength.
- Overused quads often appear tight; stretch quads and mobilize the patellofemoral joint.
- Tight hips can drive knee-dominant compensation; address hip mobility as needed.
- IT band and TFL tightness may also contribute and should be addressed.
- Posterior chain (glutes, hamstrings) often requires isolated activation and strengthening.
Rehabilitation Strategies
- Strengthen posterior chain using proprioception, hypertrophy, and neuromuscular control.
- Eccentric quad exercises help manage tendinopathies but must be balanced with posterior chain training.
- Basic glute activation exercises (e.g., front plank with hip extension, glute squeezes, donkey kicks) may be needed before complex movements.
- Single-leg exercises and progressive loading help build functional strength and control.
Posterior Knee Injuries and Screw Home Mechanism
- Posterior knee injuries (PCL, hamstrings, gastrocnemius, popliteus) often result from hyperextension or tensile overload.
- Treatment focuses on motor control, hypertrophy, and restoring normal screw home mechanism (terminal knee extension rotation).
- The screw home mechanism involves tibia or femur rotation during knee extension (10–20°).
- Popliteus muscle controls knee unlocking; its restriction can impair knee motion or indicate guarding after other injuries.
- Posterior chain (hamstrings, gastrocnemius) must be strong to prevent hyperextension injuries.
Clinical Application and Movement Analysis
- Video and angle analysis help identify faulty movement and track rehab progress.
- Compensation patterns, such as excessive hip or trunk movement and valgus collapse, signal muscle weakness or poor proprioception.
- Ongoing rehab is essential after return to play, especially post-ACL reconstruction, to address lingering deficits.
- Treatment priorities shift depending on which plane (sagittal, frontal, transverse) shows the most dysfunction.
Key Terms & Definitions
- Anterior Knee Pain — Pain located at the front of the knee, often related to overuse or movement dysfunction.
- Knee Strategy — Movement pattern dominated by knee flexion and quad activity.
- Hip Strategy — Movement pattern dominated by hip flexion and glute/hamstring activity.
- Screw Home Mechanism — Final rotation of the tibia or femur during knee extension for stability.
- Eccentric Exercise — Muscle contraction while lengthening, effective for tendon strengthening.
- Proprioception — Body’s sense of joint position and movement, critical for stability.
- Patellofemoral Joint (PFJ) — The joint between the patella and femur.
- Popliteus — Small posterior knee muscle that unlocks the knee during flexion.
Action Items / Next Steps
- Review cited articles for more on ACL and PFPS.
- Complete quiz on knee concepts during class.
- Attend knee lab for hands-on movement analysis and tendinopathy treatment practice.
- Practice identifying movement patterns (knee vs. hip strategy) in real-life or video assessments.