Objective To compare the distribution of osteophytes and joint space narrowing (JSN) between patients with acromegaly and primary generalised osteoarthritis to gain insight into the pathophysiological process of growth hormone (GH) and insulin-like growth factor type I (IGF-I)-mediated osteoarthritis.

Methods We utilised radiographs of the knee and hip joints of 84 patients with controlled acromegaly for a mean of 14.0 years with 189 patients with primary generalised osteoarthritis. Hips and knees with with doubtful or definite osteoarthritis (Kellgren–Lawrence score of ≥1) were compared in the current study. For a semiquantitative assessment of radiological osteoarthritis (range 0–3) osteophytes and JSN of the medial and lateral tibiofemoral and hip joints were scored according to the Osteoarthritis Research Society International atlas. Logistic regression analysis was performed with adjustment for age, sex, body mass index and intrapatient effect.

Results Knee and hip osteoarthritis in patients with cured acromegaly was characterised by more osteophytosis (OR 4.1–9.9), but less JSN (OR 0.3–0.5) in comparison with patients with primary osteoarthritis. Patients with acromegaly and osteoarthritis had significantly less self-reported functional disability than patients with primary osteoarthritis (p<0.001). Self reported functional disability was associated with JSN rather than with osteophytosis.

Conclusion Arthropathy caused by GH oversecretion results in osteophytosis and to a lesser extent in JSN. This observation suggests that the GH–IGF-I system is mainly involved in bone formation resulting in osteophytosis, but may possibly protect against cartilage loss.