Pathological Fracture

Abstract

HISTORY K.B. is a 13 year-old male with a 6 week history of right knee pain. The pain was progressively worsening and caused him intermittently to limp. The pain was reported as 4/10, with increase during jumping. He denied any mechanical instability. No swelling, erythema or warmth of the knee. There were no constitutional symptoms including no fever, weight loss, rash or night sweats. He had no previous pain in this knee. The patient was not participating in any organized sports other then PE in school. He could not recall any specific event or trauma. The symptoms improved by nonweight bearing and occasionally NSAIDs but did not resolve. The past medical and family histories were normal. PHYSICAL EXAMINATION Obese with BMI >97% with marked gynecomastia, normal testis, Tanner 3 pubic hair and a feminine appearing facies. Weight bearing without limp. Genu valgum bilaterally; VMO decreased tone and bulk right >left; tenderness at medial and lateral femoral condyles, otherwise unremarkable. Hip: ROM normal, tight hamstring with popliteal angle of 95, single leg squat positive for Trendelenburg, 5 hop test abnormal weak with pain on right leg. Foot: Dynamic pes planus with calcaneo valgus bilaterally. DIFFERENTIAL DIAGNOSIS Patellofemoral Dysfunction Distal femoral inflammatory process TEST AND RESULTS Plain radiographs: Osteogenic destructive lesion in the medullary cavity of right distal femur with soft tissue swelling and periosteal new bone formation - consistent with osteogenic sarcoma. CT Chest: Normal MRI of right femur: Nondisplaced fracture of right distal femoral diamethaphysis with no soft tissue mass. Edema of distal femur. Consistent with a post traumatic or pathological fracture; unlikely osteosarcoma. Bone Scan: Right distal femoral abnormality, otherwise normal. Dexa Scan: Bone Mineral Density osteopenia of lumbar spine; normal of total body and proximal femur. Laboratory: CBC, BMP, Mg, Pho, Ca, Liver Panel - WNL TSH - WNL LH, FSH - prepubertal Testosterone, PTH, Estradiol, IGF-1, Cortisol - pending CONSULT Orthopedic specialized in musculoskeletal tumor: Pathological fracture FINAL WORKING DIAGNOSIS Pathological fracture of distal femur of unknown origin TREATMENT AND OUTCOMES Non-weight bearing with crutches until completely pain free gait, then weight bearing as tolerated Home exercise program for VMO and core muscle (gluteus) strengthening and hamstring stretching No physical activity until good bony healing achieved Orthotics Follow up visit showed improved symptoms, will obtain radiographs at next visit Complete further workup for etiology of pathological fracture and possible endocrine disorder