PATELLO-FEMORAL DISORDERS – DEGENERATION AND INSTABILITY
Melanie McNeal, PT, CSCS, CFT
for patients of
DAVID LINTNER, MD
Patello-femoral pain (PFP) is the most common knee disorder. It is particularly common among adolescent girls and active individuals. The patient commonly presents with anterior knee pain that worsens with stairs, prolonged sitting/flexion, and kneeling or squatting activities. Common complaints are pain when attempting to rise after sitting and watching a movie or after a long drive. The patient may also experience swelling after activities and may complain of a “popping” sensation with ambulation.
The patella functions to aid in knee extension by acting as a pulley system to increase the angle of the moment arm of the quad tendon. Normally, as the knee flexes from 25-130° and the patella moves along the trochlear groove, it tilts medially approximately 11° and laterally rotates 6-7°. If normal patellar motion is restricted or excessive, the patella can translate out of its groove and degeneration of the patellar facets can occur. This can lead to significant pain and dysfunction. Predisposing factors that can lead to alteration in normal patello-femoral movement can include the following: trauma, osteochondritis dissecans, malalignment, tightness of the hamstring, IT band or lateral retinacula, external tibial torsion, weakness or delayed firing of the VMO, and increased Q angle.
Various conservative measures can and should be taken when addressing PFP including exercise for stretching and strengthening, bracing, taping, and orthotics. All should be considered when evaluating the patient and issuing treatment. If exercise is prescribed, the primary focus should be on quad retraining and strengthening. Biofeedback and muscle stim are helpful tools to regain neuro-muscular quad control. VMO activity is critical due to its angle of insertion and resultant pull on the patella. Studies utilizing normalized EMG values have shown that no specific exercises can be utilized to preferentially recruit the VMO over other parts of the quad. Because of this, a generalized quad strengthening program is in order.
The therapist needs to be aware of the knee angles that increase joint reaction forces on the PF joint. For closed kinetic chain activities such as the leg press, maximum joint reaction forces occur when contact between the patello-femoral surfaces is the greatest (60-90°). On the other hand, maximum joint reaction forces during open kinetic chain activities such as knee extension occur when contact between patello-femoral surfaces is the least (30-0°). With increased knee flexion, there is a concomitant increase in contact area between the patella and femur. This is important because the increased contact area serves to disperse the forces on the PF joint. On the other hand, even though contact forces are less at smaller flexion angles, the contact area is also less. Because of this, patients with degeneration at the articular surface will probably experience pain with open kinetic chain knee extensions from 30-0°.
It is important to differentiate between PF instability and PF arthritis in order to give the proper exercise prescription. Patients with PF degeneration will have pain with deep knee flexion closed chain activities whereas patients with instability will typically have pain at end range extension. Both groups should perform exercises in a pain-free range but this range will differ based on the diagnoses. Patients with PF arthritis may only be able to tolerate closed chain activities from 0-45°. On the other hand, those with instability need to exercise in deeper ranges of flexion (>30°) where the femoral condyles help to stabilize the patella.
All exercises should be in a pain-free range. McConnell taping or PF brace may need to be utilized to reduce symptoms.
STRENGTH AND NM CONTROL
- Quad sets (10 X 10sec)– the more the better – at least 100/day
- SLR – 4 way
- Shuttle/Total gym – pain-free range – bilateral and unilateral- focus on weight distribution more on heel than toes to avoid overload on Patella tendon
- Multi-hip – increase intensity as able
- Closed chain terminal knee extension (TKE)
- Leg Press
- Step-ups – forward
- Wall slides
- Calf raises
- Hamstring curls
- Hamstring stretch – hold 30 seconds
- Gastroc stretch with towel – hold 30 seconds
- ITB stretch
- Piriformis stretch
- Single leg stance – even and uneven surface – focus on knee flexion
- Plyoball – toss
- Lateral cone walking with single leg balance between each cone
- Foam roller or BAPS board balance work
- Cycle – Perform daily and increase resistance as able to work quad.
EFX – increase resistance as able
*Perform HEP daily
Exercises will be advanced in intensity based on quad tone – a patient who continues to have poor quad tone must not be advanced to activities that require high quad strength such as squats and lunges
- Continue with above exercises, increasing intensity as able
- Step-ups – forward and lateral; add dumbbells to increase I; focus on slow and controlled movement during the ascent and descent
- Squats – Smith press or standing
- Lunges – forward and reverse; add dumbbells – focus on proper form!
- Hamstring curls
- Swiss ball and foam roll hamstring exercises – supine bridge with knee flexion, bridge with HS curl
- T-band hip flexion
- Single leg squats
- Russian dead lifts – bilateral and unilateral
- Single leg wall squats
- Initiate lateral movements and sports cord: lunges, forward, backward, or side-step with sports cord, lat step-ups with sports cord, step over hurdles.
- Continue with previous proprioceptive activities
- Steamboats – 4 way; even and uneven surface
- Strength activities such as step-ups and lunges on airex
- Cycle – increase intensity; single leg cycle maintaining 80 RPM
- Jogging/Plyos: Based on quad tone, no swelling, and permission from Dr. Lintner, the patient can begin to jog at a slow to normal pace focusing on achieving normal stride length and frequency. Jogging should first be performed on a treadmill or track (only straight-aways) and then progressed to harder surfaces such as grass and then asphalt or concrete.
- Jump rope and line jumps can be initiated when the patient is cleared to jog.
- Continue to use ice after exercise
*Continue with HEP at least 3X/week
Exercises for strengthening should continue with focus on high intensity and low repetitions (6-10) for increased strength.
Progress with stretching and strengthening program (2-3X/week)
Progress jogging speed and distance
Progress plyos: Sportsmetric program can be implemented
Bilateral and unilateral plyos on shuttle
Plyos can include squat jumps, tuck jumps, box jumps, depth jumps, 180 jumps, cone jumps, broad jumps, scissor hops
Leg circuit: squats, lunges, scissor jumps on step, squat jumps
Bounding in place and for distance
Quick feet on step – forward and side-to-side – use sports cord
Progress lateral movements – shuffles with sports cord; slide board
Swimming – all styles
Focus should be on quality, NOT quantity
Landing from jumps is critical – knees should flex to 30° and should be aligned over second toe. Controlling valgus will initially be a challenge and unilateral hops should not be performed until this is achieved.
Initiate sprints and cutting drills.
Progression: Straight line, figure 8, circles, 45° turns, 90° cuts
Sports specific drills