Pyrocarbon hemiarthroplasty for the treatment of shoulder osteoarthritis in young, active patients: survival and risk factors for revision.

BACKGROUND

Glenoid erosion is the major cause for revision in shoulder hemiarthroplasty (HA). Our purpose was to assess survival and outcomes of HA with pyrocarbon head (HA-PYC) in a large series of young and high-demand patients, and to identify risk factors for postoperative revision surgery.

METHODS

96 consecutive patients (103 shoulders) who underwent HA-PYC for primary (n = 44) or secondary osteoarthritis (OA; n = 59) were prospectively followed and reviewed clinically with 2-year minimum follow-up. The mean age at surgery was 56 ± 8 years; 79 patients were still working and 59 still involved in sports. The Tornier pyrocarbon humeral head was used with a convertible press-fit stem (Ascend Flex, Tornier-Stryker). In biconcave (B2 and B3) glenoid erosion, double reaming (corrective and concentric) was performed. The quality of humeral reconstruction was assessed on postoperative computed tomography scans according to the circle method. The increase of glenoid erosion was assessed by comparing immediate and last follow-up radiographs according to the Sperling classification. The mean follow-up was 5.6 years (2-10 years).

RESULTS

The revision-free rate was 94% at 5 years and 89% at 10 years. Seven shoulders required revision surgery with conversion to reverse total shoulder arthroplasty (n = 6) or anatomic total shoulder arthroplasty (n = 1); mean time to revision was 31 months (range 10-85 months). There was no difference in outcomes and prosthesis survival between primary and secondary OA, and between shoulders with and without glenoid reaming. Increase of glenoid erosion over time was associated with significant increased pain, decreased shoulder function and subjective results, and a higher risk of revision (72% vs. 97%, P = .002). Nonanatomic humeral reconstruction with oversizing of the pyrocarbon head occurred in 24% and was associated with significantly higher rates of increased glenoid erosion (odds ratio 3.46, 95% confidence interval 1.13-10.55, P = .0295) and revision surgery (25% vs. 1.3%, P < . 001). Overall, 88% (91 of 103) of the patients were satisfied with the procedure; 92% (73 of 79) could return to work and 93% (55 of 59) to sport practice.

CONCLUSION

The use of HA-PYC for the treatment of shoulder OA in young and active patients improves shoulder function and provides low risks of glenoid erosion and revision surgery at 2- to 10-year follow-up. Pyrocarbon arthroplasty does not protect from glenoid erosion in case of nonanatomic humeral reconstruction because of oversizing of the humeral head. "Double reaming" (corrective and concentric) of the glenoid can be performed safely in case of biconcave erosion (type B2 or B3) as it does not show any adverse effect on prosthesis survival and functional results.