Hip and knee conditions
Unlike congenital disorders, which are present at birth due to genetic or developmental causes, acquired conditions develop afterward from causes such as trauma, growth-related stress, or infection. This chapter covers common acquired conditions affecting the hip and knee, along with the physical therapy interventions used to manage each one.
Legg-Calve-Perthes disease
Medical confirmation is performed through physical examination, MRI, and X-ray. The condition is most common in children under 10 years old.
Phases of Legg-Calve-Perthes disease
- Necrosis: part of the femoral head has died
- Fragmentation: the body attempts to clean up the broken pieces of bone from the area
- Re-ossification: blood flow is restored to the femoral head, and the bone begins to regrow
- Remodeling: new bone is now in place
Each phase can last months to years; the re-ossification and remodeling phases show the femoral head can heal once blood flow returns.
Physical therapy interventions for Legg-Calve-Perthes disease
- Activity modifications
- Bracing/splinting to keep the femoral head in contact with the acetabulum
- Strengthening and range of motion activities of the hip
- Report any increased pain, new limp, or skin breakdown under the brace to the supervising PT
Medical management of Legg-Calve-Perthes disease
- Use of anti-inflammatory medications
- Surgical containment (femoral or pelvic osteotomy) to keep the femoral head seated in the acetabulum - generally considered for children older than about 8 at diagnosis, or when more than half of the femoral head is involved
Transient synovitis is a self-limiting cause of hip pain and limited hip motion in children; most children have symptoms for less than two weeks, a viral cause is suspected, and children are followed to avoid missing Legg-Calve-Perthes disease.
Slipped capital femoral epiphysis (SCFE)
Etiology can be due to hormonal changes during puberty, a growth spurt, obesity, weakening of the growth plate, and family history. The most common age of injury is between 10-16 years of age.
Medical management for SCFE
Surgery is indicated once confirmed through physical examination and X-ray imaging. Delay in intervention can cause serious damage such as avascular necrosis, arthritis, or deformity of the hip joint. Surgery (in situ pinning) places a metal screw across the growth plate to fix the femoral head to the femoral neck and prevent further slipping.
Physical therapy interventions for SCFE
Physical therapy interventions are dependent upon the surgeon’s protocol post-op and will gauge the progression of activities until return to full weight bearing. Increased pain, inability to tolerate the next weight-bearing stage, or new limping during progression should be reported to the supervising PT rather than advanced independently.
The following table compares Legg-Calve-Perthes disease and slipped capital femoral epiphysis by age, typical child, what happens in the hip, findings, and management.
| Feature | Legg-Calve-Perthes disease | Slipped capital femoral epiphysis |
|---|---|---|
| Typical age | Under 10 years, most often 4-8 | 10-16 years, around the pubertal growth spurt |
| Typical child | More often boys; often small for their age | More often boys; obesity is a major risk factor |
| What happens | Blood flow to the femoral head is interrupted, so part of the head dies and collapses | The femoral head slips at the growth plate |
| Findings | Groin or thigh pain, antalgic gait, leg length discrepancy, limited abduction, flexion, and internal rotation | Similar pain, limp, and ROM limits, plus obligatory external rotation when the hip is flexed and frequent referred knee pain; an unstable slip may prevent weight bearing |
| Management | Containment: activity modification, bracing, ROM and strengthening; surgical containment in older children | Urgent: non-weight-bearing and surgical screw fixation; PT follows the surgeon’s post-op protocol |
Osgood-Schlatter disease
Common causes are repetitive movements, excessive growth during puberty, and participation in sports that require increased running and jumping. Onset is typically during the adolescent growth spurt, around ages 12-15 in boys and 8-13 in girls. Confirmation of diagnosis is through physical examination and X-ray. Sinding-Larsen-Johansson syndrome is a related overuse condition of active adolescents in which the patellar tendon’s pull irritates the inferior pole of the patella, so pain and tenderness are at the bottom of the kneecap rather than at the tibial tuberosity.
Symptoms
- Palpable swelling at the tibial tuberosity
- Pain at anterior knee
- Increased pain during running and jumping activities, with relief of pain during rest
Physical therapy interventions for Osgood-Schlatter disease
- Conservative care: activity modification (reducing high-impact running/jumping until pain improves), ice therapy, and patient education on physician-directed use of over-the-counter pain relievers
- Strengthening of lower extremity muscles to create an even pull of muscles
- Stretching of the quadriceps and hamstrings to reduce tensile pull on the tibial tuberosity
- Dynamic balance and landing-control activities that simulate sport demands
- Postural re-education when performing running, jumping activities
- Report any worsening pain, new swelling, or lack of improvement to the supervising PT
Blount’s disease
Bowing is normal in infants and should straighten by about 18 to 20 months. Bowing that persists or worsens after that age, centered at the proximal tibia, is the warning sign. Obesity, early walking and large stature are risk factors, and body weight loading the medial growth plate drives progression.
- Infantile form: noticed before about age 4; about half of cases affect both legs, and the knee may thrust laterally in stance
- Adolescent form: diagnosed after age 10; usually one leg, usually in a child who is overweight
Medical management of Blount’s disease
Bracing with a knee-ankle-foot orthosis (KAFO) is the first-line treatment for a child about 3 or younger. The brace unloads the medial growth plate and is worn during all waking hours, locked in extension for standing. It works best in a young child with one leg involved and early disease, and tends to fail with obesity, a lateral thrust, or a start after age 3. Surgery (an osteotomy of the proximal tibia, or guided growth) is used for deformity not corrected by about age 4, for advanced disease, and for the adolescent form.
Physical therapy interventions for Blount’s disease
- Teach caregivers to put on the brace and follow its wear schedule
- Check the skin under the brace
- Report increasing bowing, a new lateral thrust, skin breakdown or pain to the supervising PT
Osteochondritis dissecans (OCD)
The knee is the most common site, classically the lateral aspect of the medial femoral condyle. OCD is rare before age 6 and peaks between 13 and 17. It is two to four times more common in males and is linked to sport; repetitive microtrauma is a leading theory.
Symptoms
- Poorly localized, activity-related knee pain, sometimes with swelling
- Catching or locking in later stages, when the fragment becomes unstable or loose
- Ligament tests are normal; imaging shows the defect in the femoral condyle, which tells OCD apart from a meniscal tear
Medical management of OCD
Most lesions in children and adolescents are stable (the fragment is still attached) and are treated without surgery for at least 3 to 6 months: no running or jumping sport, often with a brace or crutch-protected partial weight bearing for the first 4 to 6 weeks. About half to two-thirds heal in 6 to 12 months, and healing is better while the growth plates are open. Unstable lesions (a loose, hinged or detached fragment), and stable lesions that do not heal, are treated surgically.
Physical therapy interventions for OCD
- Keep to the weight-bearing restriction in the plan of care
- Keep the athlete out of impact and pivoting sport until cleared
- Report new locking, giving way or joint swelling to the supervising PT: the fragment may have become unstable