Tuberosity healing in hemiarthroplasty for proximal humerus fractures remains problematic. Improved implant design and better techniques for tuberosity fixation have not been met with improved clinical results. The etiology for tuberosity failure is multifactorial; however thermal injury to host bone is a known effect of using polymethylmethacrylate for implant fixation. We hypothesized that the effect of thermal injury at the tuberosity shaft junction could be diminished by utilizing an impaction grafting technique for hemiarthroplasty stems. Five matched pairs of cadaveric humeri were skeletonized and hemiarthroplasty stems were implanted in the proximal humeri in two groups. The first group had full cementation utilized from the surgical neck to 2 cm distal to the stem (cement group) and the second group had distal cementation with autologous cancellous bone graft impacted in the proximal 2.5 cm of the stem (impaction grafting group). Thermocouples were used to measure the inner cortical temperature at the tip of the stem, surgical neck, and at the level of the cement-graft interface for both treatment groups (see Fig. 1). Experiments were initiated with the humeri fully submerged in 0.9% sodium chloride and all three thermocouples registering a temperature of 37 ± 1°C. Statistical analyses were performed with a one-sided, paired t-test.Purpose:
Methods:
Outcomes for a RSP to treat either a previous operated shoulder (revision procedure) was compared to a primary RSP. Twenty primary RSP (6M, 14F) for an irreparable rotator cuff tear (IRCT) with glenohumeral arthritis /anterior superior arch deficiency and 31 revision RSP (10M, 21F) (previous rotator or cuff surgery, hemi or total shoulder arthroplasty) were evaluated at an average of 24 months postoperatively. Mean age at the time of RSP was 72.3 for primaries 67.2 for revisions. Assessment with pre- and postoperatively SF-36, SST, ASES scores, physical exam, satisfaction surveys, and radiographs was performed. Primary RSP improvements /Revision RSP improvements were: 9.4 sf-36 PCS/ 6.3 sf-36 PCS, 1.8 SST/ 1.6 SST,31.8ASES / 17.5ASES (p<
0.05),49.2 elevation/ 14.2 elevation (p<
0.05) and 57.8 external rotation/ 30 external rotation. 71.3% Excellent/good/. 56% Excellent/ good (p<
0.05), 21.4% satisfactory/ 33.3% satisfactory, 7.1% unsatisfactory outcome/ 9.5% unsatisfactory outcome. Complications only occurred in the revisions including component disassociation, glenoid loosening, recurrent instability, and infection Primary RSP provides predictable improvements in pain and function with minimal complications. Revision RSP has a higher complication rate and improvements in pain and function are less reliable. Conventional shoulder arthroplasty for patients with IRCT with gle-nohumeral arthritis/anterior superior arch deficiency has resulted in adequate pain relief but functional improvement has not been predictable. Thus, the initial operative selection for these patients must consider the effect of a failed reconstructive attempt on patient outcomes.
