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Shepherd’s crook deformity refers to a varus angulation of the proximal femur, resulting in a bent appearance resembling a shepherd's staff.
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| Condition | Description |
|---|---|
| Fibrous dysplasia (FD) | Most common cause; multiple bones involved, especially proximal femur |
| ‣ | Subset of fibrous dysplasia with endocrine dysfunction & café-au-lait spots |
| Osteogenesis imperfecta (OI) | Bone fragility and deformity due to collagen type I defect |
| ‣ | Weakened femoral shaft susceptible to deforming forces |
| ‣ | Softening of bones from mineralization defect |
| ‣ | Low alkaline phosphatase; poor mineralization |
| ‣ | Bone dysplasia and pseudoarthrosis, often tibia but femur possible |
| Symptom | Notes |
|---|---|
| Limping or gait abnormality | Due to mechanical deformity |
| Hip/thigh pain | Often due to microfractures or stress |
| Leg length discrepancy | Asymmetrical femoral deformity can lead to LLD |
| Fractures | May occur through weakened bone or deformed region |
| Imaging Modality | Key Findings |
|---|---|
| X-ray (AP pelvis + femur) | Bowing of the proximal femur; neck-shaft angle often <90° |
| Ground-glass matrix in fibrous dysplasia | |
| Thinned cortices, deformity with expansion of bone | |
| CT scan | Defines extent of cortical thinning, lesion internal matrix |
| MRI | Useful for assessing marrow replacement and soft tissue involvement |
| Bone scan | Shows increased tracer uptake in active fibrous lesions |
(a, b) Plain radiograph demonstrating shepherd crook deformity of the bilateral femur characterized by outward bowing of the shaft. The greater trochanter of the left head of femur is also impacting against the underside of the pelvis with resultant deformity. The rest of the skeleton is also hyperlucent with thinning of the cortices. However, note the cortical thickening of the bilateral femoral shaft in contrast to the rest of the skeleton, compensating for the additional biomechanical forces due to the pathological curvature.
Case courtesy Dr Marrie Pegu, Dr Supriya Paul & Dr Nabarun Das sir MD // 2025 // #SMCHCase