Monostotic Patellar Paget’s disease: A case report

Introduction

Paget’s disease of bone is the second most common skeletal metabolic disorder following osteoporosis in humans. Paget’s disease’s incidence increases with age with male to female ratio 2:1. The disease is characterized by disturbed osteoblastic and osteoclastic activity that alters bone architecture. Etiology of Paget’s disease remains unknown and the majority of patients are asymptomatic with the rest presenting skeletal pain. Three main phases have been described: the osteolytic phase, the mixed osteolytic and osteoblastic phase, and the terminal sclerotic phase. The most commonly affected skeletal areas are the skull, spine, pelvis and long bones. In most of the cases, Paget’s disease appears in a polystotic form, but in 10-15% of cases monostotic with only one bone affected. Patella involvement in monostotic or polystotic Paget’ s disease is extremely rare.

Purpose of the study

We report a case of monostotic Paget’s disease of the patella.

Case report

We present a 60-year-old male with persistent pain in his anterior left knee joint over the past two years. The patient gave no family or personal history of other musculoskeletal disorder. During physical examination the left patella was enlarged palpated, while medial knee joint space appeared tender along with patello-femoral crepitus. Plain radiographs revealed gross enlargement and coarsening of the trabecular pattern of the left patella. Moving on with bone scan, there was increased uptake only over the same area and taking all the above under consideration we diagnosed the patient with Paget’s disease.

Results

The patient was successfully conservatively treated with oral medications including biphosphonates, vitamin D and calcium supplements curing patient’s Paget’s disease with totally resolved knee joint pain at three months follow-up.

Conclusion

Patients with Paget’s disease are normally treated conservatively. Paget's disease of the patella is extremely rare but should be taken under consideration in the differential diagnosis of anterior knee joint pain in elderly patients.