We tried to evaluate all patients with Kienböck disease managed with any of the RSO and CSO procedures at least six months after their last operation (Mean follow-up of 46 months). Overall, 23 patients were included in our study, out of which 6 had more than one operation. Pain score in the Mayo wrist questionnaire was significantly lower in the RSO group than the CSO group. We found a significantly limited range of motion and grip strength compared to the contralateral side in the RSO group. Only wrist flexion was significantly limited compared to the other side in CSO group. Significantly limited wrist range of motion was observed in patients with re-operation for their Kienböck disease.
We evaluated the failure rate of the two standard procedures in Kienböck patients. As follow-up periods differed significantly, we calculated failure rates as 1.16% and 2.59%, for RSO and CSO, respectively. Gay et al. found an 18% (2 patients out of 11) failure rate due to persistent pain who required revision surgery in their series of patients after capitate shortening osteotomy (mean follow-up=67.4 months); both underwent revision surgery due to persistent pain . Viljakka et al. reported a 25% (4 out of 16) failure rate after RSO in 25-year follow-up; one underwent silicone implant arthroplasty, one had wrist fusion, and the other two patients had disabling pain in the follow-up .
We found no reasonable correlation between the radiographic and clinical findings whereas some patients with improved radiologic stage showed limited wrist motion and grip strength. The radiological staging did not correlate with patients’ satisfaction with the procedures. Two patients had worsened radiologic staging with Lichtman IIIA converted to IIIB, the same as Afshar et al.’s findings . Just like Watanabe et al. implicated RSO as a protective measure to Lichtman stage IV in Kienböck patients in a 21-year follow-up , we found no patient in stage IV in neither groups. However, Luegmair et al. found 8 of 36 patients converted stage IIIA to IV Lichtman after RSO in a 12-year follow-up .
DASH score seems to be conversely correlated with follow-up duration since we found a DASH score of 19 and 21, in RSO and CSO with 57 and 20 months follow-up. Afshar et al. found patients with RSO and CSO with 24.2 and 20 DASH scores in 3.2 and 3.1 years follow-up respectively. Luegmair et al. reported a DASH score of 12 in a 12-year follow-up , and Viljakka et al. found a DASH score of 6 in patients with RSO in a 25-year follow-up .
The same trend was observed in Mayo wrist score. We found Mayo wrist score of 64.5 in our RSO group, while the RSO group in Luegmair et al. had a Mayo wrist score of 75 , and Ebrahimzadeh et al. reported a score of 77 in their cohort with a mean 7-year follow-up .
Range of motion
We found a significantly limited range of motion in wrist flexion and extension in the RSO group. Limited wrist range of motion was previously reported in several cohorts with mid-term follow-up for RSO [4, 12, 14] and CSO [10, 12, 15]. In a recent systematic review of 172 wrists with RSO procedure over ten years of follow-up, the mean wrist arc of motion was comparable to our results (107.4 [SD 10] vs. 106 degrees) . In a long-term study, extension and flexion were 93% and 76% of the unaffected side . Although wrist flexion was also limited in our study, only wrist extension was significantly lower in the involved side compared to the other side in CSO group.
Afshar et al. found grip strength 70.1% and 75.2% of the unaffected side in RSO and CSO groups . Additionally, in RSO, grip strength in Rodrigues-Pinto et al. was 73%  and in Viljakka et al. was 95% of the contralateral side . Singer et al. found 63% , and Gay et al. reported 72% of unaffected side grip strength in CSO . Similar to these studies, we found grip strength was also diminished compared to the other side in RSO and CSO (75.3% and 71.69%, respectively). Although the literature shows that wrist motion and grip strength have improved after either of the procedures, all patients with Kienböck disease should be cautious about a diminished range of motion and grip strength. Neither of these procedures could take them back to unaffected side values.
Multiple operation results
Ultimately, three patients in each RSO and CSO group underwent re-operation due to residual pain and disability. However, residual pain in one patient with CSO and then ALD resulted in wrist arthrodesis. All these patients had worsened radiologic stage, and most of them are experiencing some degree of wrist pain and disability in daily activities. These patients were usually excluded in previous studies or reported as a failure. We assigned them into a separate group to further evaluate their condition after revision surgery. All but one had a poor result in Mayo score (<65 points). Additionally, all of them had a worse radiologic stage compared to before operation, and all but one was in stage IIIB Lichtman-Stahl. However, we found no statistically significant difference in radiologic stage in the re-operation group compared to patients in RSO and CSO groups.
Due to patients' limitations for the follow-up, we could not include all patients in the current study. Also, patients’ pre-operative range of motion and grip strength were not complete for all patients to be used for comparison. Therefore, we used the contralateral side for the comparison. The low sample size is an inevitable issue due to the low prevalence and rarity of Kienböck disease while, at the same time, not all are candidates for surgery.
In conclusion, we evaluated three different Kienböck disease procedures with a mean 46 months follow-up. We found no significant difference in functional, satisfaction, or radiologic properties between RSO and CSO procedures. However, patients who underwent RSO had lower pain scores among others.