Humeral head implant with inlay glenoid component may lead to glenohumeral recentering
Use of a non-spherical humeral head implant coupled with an inlay glenoid component may lead to glenohumeral recentering in patients with eccentric glenoid wear and posterior subluxation, according to published study results.
Sercan Yalcin, MD, and colleagues used the Walch index and point of contact ratio method to compare ratios of preoperative and postoperative humeral head subluxation in 49 patients with primary glenohumeral osteoarthritis with a posteriorly subluxated humeral head who underwent total shoulder arthroplasty with combination non-spherical humeral head resurfacing and inlay glenoid replacement (Hemi-CAP OVO/Inlay Glenoid Total Shoulder System, Arthrosurface). Radiographic measurements were performed by two orthopedic surgeons and researchers included means of two independent measurements in the final analysis for each shoulder. Researchers also screened for postoperative complications, dislocation events and radiographic loosening.
Among the total cohort, 29 shoulders of 28 patients were eligible for screening. In these shoulders, researchers noted Walch type B1 glenoids in 3 shoulders, B2 in 22 shoulders and B3 4 shoulders.
Results showed a mean preoperative Walch index of approximately 56.57% and mean preoperative point of contact ratio of approximately 62.97%. Researchers found a mean postoperative Walch index and point of contact ratio of approximately 49.47% and 50.08%, respectively. Researchers noted both methods had significant differences between preoperative and postoperative subluxation ratios and found good-excellent inter-rater reliability. At a mean follow-up of 37.79 months, results showed patients had an overall complication rate of 10.34%, with deep vein thrombosis in 3.22% of patients and infection in 6.45% of patients. Researchers found no shoulder dislocations and no loosening on postoperative radiographs.
According to Yalcin, posterior humeral head subluxation, bone loss and decentering of the joint affect both short- and long-term results of shoulder arthroplasty. Although alternative approaches — such as restoring the joint line with various techniques using advanced imaging, wedged implants, patient specific instruments and reverse shoulder arthroplasty — have been used to resolve this issue, Yalcin said the results of this study demonstrated a simpler approach that had excellent previously reported clinical results.
“This study demonstrated that when using a non-spherical humeral head with an inlay glenoid in cases of Walch type B2/3 glenoids that the joint is recentered with no evidence of loosening in all cases,” Yalcin told Healio Orthopedics. “This procedure holds promise as a simpler, cost effective option for patients suffering from glenohumeral osteoarthritis with posterior humeral head subluxation.”