'Snapping' knee secondary to a tibial osteochondroma.
BACKGROUND
Osteochondroma is the most common bone tumour and is usually found around the knee. Typical presentations range form painless masses around the joint to mechanical irritation caused by direct pressure over surrounding muscles. Snapping of the knee caused by an osteochondroma however has not been described in literature.


METHODS
An active 19-year-old gentleman presented with snapping of the left medial hamstring tendon for over 5 years, but with recent increase in frequencies of attack. The patient was initially diagnosed to have a sporting injury. Radiological investigation showed an opaque lesion on the medial border of the proximal tibia, which was suggestive of an osteophyte.


RESULTS
The lump was surgically excised and the patient made good recovery with resolution of symptoms. Histological results revealed the lesion to be that of an osteochondroma.


CONCLUSIONS
Although rare, osteochondroma should be considered as a differential when approaching a case of snapping knee pain.
Yoong-Leong Oh
Jacob
J
Department of Orthopaedic Surgery, Alexandra Hospital, Singapore.
Tan
Ker-Kan
KK
Wong
Yue-Shuen
YS
D001265:Athletic Injuries / Q000175:diagnosis; D001859:Bone Neoplasms / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D015831:Osteochondroma / Q000175:diagnosis*; D013977:Tibia; D055815:Young Adult