We describe 22 cases of bizarre parosteal osteochondromatous proliferation, or Nora’s lesion. These are surface-based osteocartilaginous lesions typically affecting the hands and feet. All patients were identified from the records of a regional bone tumour unit and were treated between 1985 and 2009. Nine lesions involved the metacarpals, seven the metatarsals, one originated from a sesamoid bone of the foot and five from long bones (radius, ulna, tibia, and femur in two). The mean age of the patients was 31.8 years (6 to 66), with 14 men and eight women. Diagnosis was based on the radiological and histological features. The initial surgical treatment was excision in 21 cases and amputation of a toe in one. The mean follow-up was for 32 months (12 to 162). Recurrence occurred in six patients (27.3%), with a mean time to recurrence of 49 months (10 to 120). Two of the eight patients with complete resection margins developed a recurrence (25.0%), compared with four of 14 with a marginal or incomplete resection (28.6%).

Given the potential surgical morbidity inherent in resection, our data suggest that there may be a role for a relatively tissue-conserving approach to the excision of these lesions.

We reviewed nine patients at a mean period of 11 years (6 to 16) after curettage and cementing of a giant-cell tumour around the knee to determine if there were any long-term adverse effects on the cartilage. Plain radiography, MRI, delayed gadolinium-enhanced MRI of the cartilage and measurement of the serum level of cartilage oligomeric matrix protein were carried out. The functional outcome was evaluated using the Lysholm knee score.

Each patient was physically active and had returned to their previous occupation. Most participated in recreational sports or exercise.

The mean Lysholm knee score was 92 (83 to 100). Only one patient was found to have cartilage damage adjacent to the cement. This patient had a history of intra-articular fracture and local recurrence, leading to degenerative changes.

Interpretation of the data obtained from delayed gadolinium-enhanced MRI of the cartilage was difficult, with variation in the T1 values which did not correlate with the clinical or radiological findings. We did not find it helpful in the early diagnosis of degeneration of cartilage. We also found no obvious correlation between the serum cartilage oligomeric matrix protein level and the radiological and MR findings, function, time after surgery and the age of the patient.

In summary, we found no evidence that the long-term presence of cement close to the knee joint was associated with the development of degenerative osteoarthritis.

We retrospectively studied local recurrence of giant cell tumour in long bones following treatment with curettage and cementing in 137 patients. The median follow-up time was 60 months (3 to 166). A total of 19 patients (14%) had at least one local recurrence, the first was diagnosed at a median of 17 months (3 to 29) after treatment of the primary tumour. There were 13 patients with a total of 15 local recurrences who were successfully treated by further curettage and cementing. Two patients with a second local recurrence were consequently treated twice. At the last follow-up, at a median of 53 months (3 to 128) after the most recent operation, all patients were free from disease and had good function.

We concluded that local recurrence of giant cell tumour after curettage and cementing in long bones can generally be successfully treated with further curettage and cementing, with only a minor risk of increased morbidity. This suggests that more extensive surgery for the primary tumour in an attempt to obtain wide margins is not the method of choice, since it leaves the patient with higher morbidity with no significant gain with respect to cure of the disease.