Introduction: The purpose of this study is to compare the radiographic results of two glenoid preparation techniques by analyzing periglenoid radiolucencies.

Material and methods: The series consists of 72 shoulder arthroplasties with primary osteoarthritis. Shoulders were divided into 2 groups based on glenoid preparation technique:

Group 1: 37 shoulders operated on between 1991 and 1995 with flat back, polyethylene glenoid implants cemented after curettage of the keel slot.

Group 2: 35 shoulders operated on between 1997 and 1999 with the same glenoid implants cemented after cancellous bone compaction of the keel slot.

At least 3 of the following 4 fluoroscopically positioned, postoperative AP radiographs were analyzed: immediate postoperative, between the 3rd and 6th months, at one year and at two years postoperative. The immediate and the two year radiograph were required for study inclusion. The radiolucent line score (RLLS) was calculated using the technique of Molé, involving the summation of radiolucencies in each of six specified zones. The RLLS was compared between the two groups.

Results: On the immediate postoperative radiographs the average of the total RLL score of the 9 analyzes was 2.39 in Group 1 and 1.67 in Group 2 (p=0.042). There was a statistically significant association between the glenoid preparation technique and the incidence of radiolucency around the keel as well (p=0.001). There was no significant difference in radiolucency behind the faceplate between the two groups (Group 1: 1.54 and Group 2: 1.41; p=0.394). On the 2-year postoperative radiographs the average RLL score of the 9 analyzes were 6.44 in the Group1 (4.05 under the tray, and 2.39 around the keel), and 4.19 in Group2 (p=0.0005) (2.86 under the tray, and 1.33 around the keel). The radiolucency around the keel and behind the faceplate (p=0.0005) was significantly more important (p=0.001) in the curettage glenoid preparation population. A significantly higher degree of progression of the total RLL score (p=0.002) and of the radiolucency behind the faceplate (p=0.001) was observed in the curettage glenoid preparation group.

Discussion/conclusion: Preparation of the glenoid component keel slot with cancellous bone compaction is radiographically superior to the curettage technique with regard to periglenoid radiolucencies.