Patellar osteomyelitis presenting as prepatellar bursitis.

Peripatellar lesions causing knee pain include cellulitis, bursitis, synovitis, septic arthritis and patellar osteomyelitis. We present here two cases of patellar osteomyelitis which were misdiagnosed as prepatellar bursitis. Operative treatment was required for these lesions. Patellar osteomyelitis should always be considered when treating a peripatellar lesion, although it is very rare condition.