This study evaluated the effect on movement under load of three different techniques for re-attachment of the tuberosities of the humerus using test sawbones. In the first, the tuberosities were attached both to the shaft and to each other, with one cerclage suture through the anterior hole in the prosthesis. The second technique was identical except for omission of the cerclage suture and in the third the tuberosities were attached to the prosthesis and to the shaft. An orthogonal photogrammetric system allowed all segments to be tracked in a 3D axis system. The humeri were incrementally-loaded in abduction, and the 3D linear and angular movements of all segments were calculated. Displacement between the tuberosities and the shaft was measured.

The first and second techniques were the most stable constructs, with the third allowing greater separation of fragments and angular movement. Separation at the midpoint of the tuberosities was significantly greater using the latter technique (p < 0.05). The cerclage suture added no further stability to the fixation.

We made a prospective study of 58 consecutive Neer II total shoulder replacements in 49 rheumatoid patients. Cemented glenoid and press-fit humeral components had been used. After a mean follow-up of 9.5 years (7 to 13), 11 patients (15 shoulders) had died, one shoulder had been arthrodesed and five patients (five shoulders) had been lost to follow-up.

Of the remaining 37 shoulders 29 were painfree or had only slight discomfort, four had pain on unusual activity, and four had moderate or severe pain. There were satisfactory improvements in the mean range of active elevation (53° to 75°) and external rotation (5° to 38°); satisfactory performance of the activities of daily living had been maintained throughout follow-up. Radiographs showed loosening in ten shoulders of nine glenoid and nine humeral components but of these only three had significant symptoms. Three loose glenoid components and two loose humeral components required revision.

We consider that the Neer total shoulder replacement provides a reasonable medium to long-term outcome in rheumatoid arthritis, but recommend that the humeral component should be routinely cemented.