The study evaluates the procedures of capitate shortening osteotomy with or without vascularized bone grafting (VBG) for the treatment of stage II or IIIA Kienböck's disease with neutral ulnar variance. Forty-five patients with stage II (n = 21) and IIIA (n = 24) Kienböck's disease were included in the study. Patients were classified into two groups; isolated capitate shortening (ICS) group included 21 patients (stage II [n = 10] and stage IIIA [n = 11]) treated by capitate shortening without VBG of the lunate. Combined capitate shortening (CCS) group includes 24 patients (stage II [n = 11] and stage IIIA [n = 13]) who treated by capitate shortening combined with VBG of the lunate from the dorsal distal radius based on the fourth + fifth extensor compartment artery. All patients were evaluated pre- and post-operative for pain as measured by visual analogue scale score (VAS), range of motion (ROM), grip strength, modified Mayo wrist score (MMWS), lunate height index (LHI) ratio, and carpal height index (CHI) ratio. The mean operative time for CCS procedure was 85min (76 to 120) and for ICS was 58min (47 to 65). The mean follow-up period for all patients was 33months (29 to 47). Patients with stage IIIA Kienböck's disease treated by CCS procedure had better post-operative VAS, ROM, grip strength, MMWS, LHI, and CHI ratio than patients treated by ICS procedure. ICS procedure reported 28% failure rate versus 8% for CCS. No differences were found between CCS and ICS procedures in patients with stage II Kienböck's disease in the term of clinical, radiographic outcomes, or failure rate. Using CCS procedure for the treatment of stage IIIA Kienböck's disease (lunate height collapse) with neutral ulnar variance can restore height and dimensions of the collapsed lunate and subsequently improve the final outcomes with lower failure rate. However, in patients with stage II Kienböck's disease (maintained lunate height), no advantages were noticed for CCS over ICS procedure. Lunate height index might be considered a prognostic factor for the treatment outcomes of Kienböck's disease.