Grey matter volume reduction in the cerebellum of hip osteoarthritis patients: insights from pre- and postoperative VBM analysis

Purpose: This exploratory study aimed to investigate grey matter (GM) volume changes in patients with hip osteoarthritis undergoing hip joint arthroplasty using voxel-based morphometry (VBM), assessing pre- and postoperative differences and comparing findings with healthy controls (HC). Material and methods: Twenty-one patients with unilateral hip osteoarthritis before and after hip prosthesis insertion (PT group) and 16 HC were studied. All participants were right-handed and free from neurological or psychiatric conditions. Structural T1-weighted MRI scans were acquired at 3 T before and after surgery in the PT group, with an average interval of 112 days, and in the HC group. VBM analyses were conducted using the Computational Anatomy Toolbox (CAT12). Preoperative GM volume differences between PT and HC groups, as well as changes in PT before and after surgery, were analysed using statistical parametric mapping with family-wise error (FWE) correction. Results: Preoperative comparisons revealed a significant reduction in grey matter volume in the ipsilateral cerebellar Crus II in the PT group compared with HC (pFWE = 0.004). No significant GM volume differences were found between pre- and postoperative assessments in the PT group. Although all patients demonstrated marked clinical improvement at 1-month follow-up, MRI-clinical correlations could not be performed because clinical assessments and postoperative MRI were not acquired at the same time. Conclusion: The findings provide preliminary evidence of cerebellar GM changes in patients requiring hip prostheses, suggesting central nervous system involvement in chronic hip pathology. Interpretation is constrained by the modest sample size and by variability in postoperative imaging intervals. The absence of significant postoperative changes highlights the need for further research to explore the timeline and extent of neuroplastic recovery. These results underscore the importance of considering central adaptations in the management of peripheral joint disorders.