Clinical outcomes of scaphocapitate fusion using single headless cannulated screw following lunate excision in advanced-stage Kienböck disease

Purpose This study aimed to evaluate the clinical and radiological outcomes of lunate excision scaphocapitate fusion (LESCF) using a single headless cannulated compression screw in patients with advanced Kienböck disease (Lichtman IIIb–IV). The hypothesis was that this technique would provide significant pain relief, functional improvement, and comparable union rates to multi-screw methods while reducing implant-related morbidity. Methods A retrospective single-center case series included 24 patients (8 males, 16 females; mean age 37.3 ± 8.5 years) who underwent LESCF between June 2021 and June 2023. Minimum follow-up was 24 months (mean 33.6 ± 4.1). Clinical evaluation included pain (VAS), wrist function (Modified Mayo Wrist Score), grip strength, and range of motion. Radiological assessment involved union rate and time, radioscaphoid angle (RSA), carpal height ratio (CHR), Modified Carpal Ulnar Distance Ratio (modified-CUDR) and ulnar variance. Results Radiographic union was achieved in all cases (100%) at a mean of 3.5 ± 1.2 months. Mean VAS score decreased from 7.2 ± 1.1 to 2.1 ± 1.0 (p < 0.001), and Modified Mayo Wrist Score improved from 47 ± 12 to 74 ± 10 (p < 0.001). Grip strength increased from 55 ± 15% to 75 ± 18% of the contralateral hand (p < 0.01). Flexion–extension arc slightly decreased (81° ± 10 to 76° ± 9; p < 0.05), while radioulnar deviation changes were minimal. RSA improved from 48° ± 7 to 41° ± 6 (p < 0.01), with no significant change in CHR or ulnar variance. Modified CUDR values were found to be 0.834 ± 0.104 in the preoperative period and 0.804 ± 0.116 in the postoperative period. One patient (4.2%) reported mild screw irritation without surgical intervention; no other complications occurred. Conclusion Single-screw scapho-capitate fusion and lunate excision can be considered a suitable treatment option for advanced Kienböck’s disease, offering pain reduction, positive effects on functional recovery, acceptable healing rates, and a low risk of complications. However, larger, prospective studies are needed to demonstrate the long-term results of this method and its comparative effectiveness with other surgical techniques.