Metaphyseal Core Decompression of the Distal Radius for Early Lunate Necrosis

Background: Metaphyseal core decompression of the distal radius (MCD) is clinically effective in early lunate necrosis without changing individual wrist mechanics. Its concept is based on the induction of physiologic mechanisms known as physiologic fracture healing response. However, this biological concept does not yet have its place in the historically developed mechanical concepts about Kienböck's disease and requires more detailed clarifications to understand when a change of individual wrist mechanics might be unnecessary. Methods: Thirteen consecutive cases, Lichtman stage I (n = 1) or II (n = 12), confirmed by conventional MRI, were treated by MCD. Time off work, changes in magnetic resonance imaging of the lunate, as well as clinical outcome using modified Mayo wrist score were evaluated at final follow-up. Results: Return to work was at six (1-10) weeks after surgery. MRI controls at short-term generally demonstrated stop of progression and signs of bone healing. Independently from ulna variance complete signal normalization was observed in six and a distinct, yet incomplete decrease of lunate bone marrow edema and zones of fat necrosis was confirmed in further six cases after a mean of 21 (13-51) weeks. One patient had radiographic controls only, stating normal healing at 56 months. After a mean follow-up of 37 (12-70) months the clinical outcomes were excellent in eleven and good in two cases (mean 95% in modified Mayo wrist score). Conclusions: In stage I and II lunate necrosis MCD stops disease progression, it improves clinical symptoms and induces normalization of lunate bone signal alterations in MRI. Findings suggest that stage I and II lunate necrosis can be effectively treated without alterations of individual wrist mechanics. Future studies are necessary to readjust common concepts regarding Kienböck's disease, especially focusing on conservative therapy.