Wrist osteoarthritis : causes, treatment and outcome

Sammanfattning: Wrist osteoarthritis is rare compared to osteoarthritis in the finger joints or thumb base and affects younger patients. Its etiology is heterogenous, and osteoarthritis may be caused by traumatic injuries, as well as by nontraumatic medical conditions. The primary aim of this thesis was to improve knowledge about the causes, surgical treatment, and postsurgical outcomes in painful wrist osteoarthritis. A common cause of wrist osteoarthritis is the scaphoid nonunion advanced collapse, which may develop after a scaphoid nonunion. In Paper I the nationwide incidence, treatment and nonunion rates of scaphoid fractures were investigated by evaluating data on 34,377 patients registered in the Swedish National Patient Register (NPR) from 2006–2015. NPR data was validated in 300 patients and 41% of scaphoid fracture diagnoses were false positives. Incidence was 22 per 105 person-years. Median age was 26 years and 69% of the patients were men. Surgical treatment was performed in 5% of patients and 2% developed a diagnosed nonunion. In paper II, we analyzed the morphology of the Posterior Interosseous Nerve (PIN)—a sensory nerve terminating in the dorsal wrist capsule—by light microscopy in patients with wrist osteoarthritis, as compared to healthy controls. No morphological differences were found. Surprisingly, most patient and control samples exhibited some degree of pathology. Paper III was a prospective longitudinal interventional study on the effect of partial wrist denervation on patient-reported outcomes and objective function in 60 patients during the first year after surgery. Generalized Estimating Equations (GEE) were used for statistical analyses. Disabilities of the Arm, Shoulder, and Hand (DASH) and Patient-Rated Wrist Evaluation (PRWE) improved significantly, but improvements were small and of unclear clinical significance. Quality of life and objective function did not improve. We found no complications. 17 patients required further surgery due to lack of improvement. Paper IV was a prospective longitudinal study of 80 patients analyzing the effect of preoperative pain catastrophizing, anxiety, depression, and Sense of Coherence (SOC) on DASH, PRWE, quality of life, grip strength, and range of motion (ROM) during the first year after wrist surgery. GEEs were used to analyze the effect of psychological factors on outcomes. Pain catastrophizing and anxiety had negative impacts on DASH and PRWE. Anxiety predicted lower postoperative quality of life, and pain catastrophizing had a negative impact on grip strength. SOC had no impact on outcomes. In conclusion, scaphoid fractures mainly affect young males and the risk for a nonunion after a fracture is low. It is unclear if partial wrist denervation has a clinically relevant effect in wrist osteoarthritis. Preoperative presence of anxiety or pain catastrophizing results in a worse postoperative outcome in patients with wrist osteoarthritis.