Complications
Chondrolysis is defined as acute dissolution of articular cartilage in association with rapid progressive joint stiffness and pain. Aetiology of chondrolysis is unknown. However, an immunological and autoimmune theory has been proposed.[26] Chondrolysis can occur in untreated SCFE but usually occurs as a complication of treatment. Contributory factors are persistent pin penetration of the joint, advanced SCFE manipulative reduction, prolonged immobilisation in hip spica, and realignment osteotomies.
Chondrolysis in SCFE is exceedingly rare with current treatment methods.
Diagnosis of chondrolysis is made by plain antero-posterior or lateral x-rays of both hips when <50% of joint space is reduced when compared with the uninvolved hip; and the joint space is <3 mm with bilateral involvement.
Hip, thigh, and knee pain associated with hip joint stiffness are common presenting features.
Physical examination characteristically reveals restricted range of motion, particularly internal rotation. Management includes protected weight bearing, physiotherapy to improve range of motion, and anti-inflammatory medication. The prognosis is better for chondrolysis than for osteonecrosis.[38] Painful stiff hip can be treated with hip joint distraction, arthrodesis, or arthroplasty.
The retroverted deformity of the femoral head remodels over a period of time. However, disabling external rotation deformity persists in a few patients causing gait disturbance and femoro-acetabular impingement. This leads to pain and restricted range of motion at the hip. This can be corrected by creating a secondary deformity counteracting the principal deformity through osteotomy. In SCFE the deformity is in the physis and osteotomy close to the apex of deformity is preferable. Both femoral neck and inter-trochanteric osteotomies have been performed. Cuneiform osteotomy performed through the femoral neck achieves better results but is technically demanding and associated with increased risk of osteonecrosis.[34][35]
Many surgeons have a low threshold for prophylactic fixation of contralateral hip in pathological SCFE (underlying metabolic disorder or endocrinopathy). There is no consensus on prophylactic fixation of contralateral hip in idiopathic SCFE.
Many variables have been investigated to predict subsequent SCFE in unilateral idiopathic SCFE. These include: sex, symptom duration, obesity, trauma, severity of index slip, laterality, patient age, modified Oxford bone score, and bone age.[36]
The posterior sloping angle (PSA), defined as the angle between the line along the plane of the physis and the line perpendicular to the femoral neck-diaphyseal axis on axial radiograph, has been shown to be predictive of a contralateral slip in patients presenting with unilateral SCFE.[37] In one study, PSA was more predictive in girls; the authors recommended prophylactic pinning with a PSA >13.[37] According to one meta-analysis, younger patients with a high PSA of the unaffected hip are those most likely to benefit from prophylactic fixation.[36]
Prophylactic pinning is also likely to be beneficial for the long-term outcome of SCFE in some cases where underlying metabolic disorders are present. However, clinicians should consider each case on its own merits before offering prophylactic intervention.
Factors associated with osteonecrosis in SCFE include unstable SCFE; forcible reduction of stable SCFE; pin penetration of posterosuperior quadrant; multiple pins.[40][41][42][43][44]
In stable SCFE the prevalence of osteonecrosis is low; in unstable SCFE the reported prevalence is highly variable (3% to 84%).[5][6][45][46][47] Two studies have found the rate of avascular necrosis to be approximately 20% in unstable SCFE.[41][48]
Presenting features include hip, thigh, or knee pain; restricted range of motion of the hip is common, particularly internal rotation. If osteonecrosis is suspected, initial imaging is radiography of the area of interest.[49] Collapse of the femoral head, cyst formation, and sclerosis are characteristic radiological findings. If radiological findings are normal or suspicious for osteonecrosis, MRI of the area of interest without contrast is usually an appropriate next imaging study. MRI without contrast or CT without contrast, of the area of interest, are usually appropriate as the next imaging studies if there is known osteonecrosis with articular collapse, as identified by radiography, and surgery is planned.[49]
Treatment is challenging. Preventing collapse of the femoral head and reconstitution of the collapsed femoral head is the key component of treatment. Protected weight bearing, physiotherapy to maintain range of motion at hip, anti-inflammatory/analgesic medication, and bisphosphonates are recommended.[50] Surgical treatment involves decompression of the necrotic area and filling with autograft, allograft, or live fibular graft. Results have been inconsistent.
Use of this content is subject to our disclaimer