<aside>
Apophysitis is a traction-induced inflammatory condition involving the apophysis—a secondary ossification center where tendons or ligaments attach to bone. It occurs almost exclusively in skeletally immature individuals (children and adolescents), particularly during growth spurts, when the apophysis is weaker than the surrounding tendon or bone.
</aside>
| Feature | Description |
|---|---|
| Mechanism | Repetitive traction by muscles/tendons on an open apophysis → inflammation, microtrauma |
| Vulnerable period | Adolescence, during rapid growth (10–16 years) |
| Healing | Resolves with physeal closure and skeletal maturity |
Common Sites of Apophysitis
| Condition | Affected Apophysis | Involved Tendon |
|---|---|---|
| ‣ | Tibial tubercle | Patellar tendon |
| ‣ | Inferior pole of patella | Patellar tendon |
| ‣ | Calcaneal apophysis | Achilles tendon |
| ‣ | Base of 5th metatarsal | Peroneus brevis |
| ‣ | Medial epicondyle (humerus) | Flexor-pronator tendons |
| ‣ | Iliac crest | Abdominal wall muscles |
| ASIS/AIIS apophysitis | Anterior superior/inferior iliac spine | Sartorius / rectus femoris |
| Hip apophysitis | Greater trochanter | Gluteus medius and minimus |
| Feature | Description |
|---|---|
| Age group | 10–16 years |
| Symptoms | Activity-related localized pain over tendon insertion point |
| Tenderness | Focal, reproducible over affected apophysis |
| Swelling | May be present; often mild |
| Aggravating factors | Running, jumping, directional changes, high-impact activities |
| Modality | Imaging features |
|---|---|
| XR | • Apophyseal fragmentation/irregularity: Classic but late finding (e.g., tibial tubercle in OSD) |
| • Soft tissue swelling: Sometimes visible | |
| • Asymmetry: Comparison with contralateral side useful | |
| MR | • T1: Normal or subtle fragmentation |
| • T2/STIR: Edema in apophysis, adjacent bone marrow, and insertional tendon | |
| • Fat-suppressed sequences: Highlight fluid/inflammation around the apophysis | |
| US | • Hypoechoic swelling at tendon insertion |
| • May show fragmentation or bony irregularity | |
| • Dynamic assessment of tendon-bone interface |
| Condition | Distinguishing Features |
|---|---|
| Tendinopathy | Older age group; affects mature skeleton |
| Avulsion fracture | Acute onset with fragment displacement; trauma history |
| Infection (osteomyelitis) | Fever, elevated CRP/WBC, lytic lesion with periosteal reaction |
| Bone tumor (rare) | Night pain, no activity relationship, aggressive features on imaging |
| Strategy | Description |
|---|---|
| Rest/activity modification | Avoid aggravating activities; return to sport as tolerated |
| Ice, NSAIDs | Symptomatic relief |
| Stretching and strengthening | Address tight quadriceps/hamstrings or imbalanced mechanics |
| Physical therapy | Correction of biomechanical risk factors |
| Prognosis | Excellent; resolves with skeletal maturity |