Compaction grafting effective for press-fit shoulder arthroplasty at 5 years postop

No correlations were found between the maximum thickness of radiolucent lines and ASES scores, SST scores or improvement in VAS scores at final follow-up.

The adjunctive use of compaction bone grafting in shoulder arthroplasty involving an uncemented press-fit humeral component prosthesis yields favorable clinical and radiographic results at 5 years mean follow-up, according to a study by researchers in Texas.

Michael A. Wirth, MD, and colleagues at the University of Texas Health Science Center in San Antonio evaluated their results using compaction bone grafting in 58 shoulders of 53 patients followed for at least 24 months postop. The study included 42 hemiarthroplasties and 16 total shoulder arthroplasties in 33 men and 25 women who received surgery at a mean age of 60 years.

"In January 1992, we began using compaction bone grafting to secure fixation of the humeral component in shoulders in which the interference fit of that component was suboptimal as a result of poor bon quality in the proximal part of the humerus. The objective was to achieve implant stability buy using cancellous, morselized bone graft and hopefully to obviate the need for cement fixation," the authors said.

In all cases, surgeons implanted a DePuy Global shoulder modular prosthesis (DePuy Orthopaedics, a Johnson & Johnson Company). This device features a cylindrical diaphyseal region and proportionately sized metaphyseal regions incorporating a superior-to-inferior taper, according to the study.

Surgeons used cancellous bone from the humeral head in all primary arthroplasties and cancellous allograft for revision cases. The prosthesis was used to compact the graft material, with additional graft added until a mallet was needed to drive the prosthesis into final position, the authors said.

At an average follow-up of 69 months, mean active external rotation had improved to 34.5° from 9° preoperatively (P<.0001), and mean active total elevation improved to 123.2° from 92° preoperatively (P<.0001), according to the study.

Average scores for the Simple Shoulder Test (SST) improved from 4.4 points preoperatively to 9.1 points at last follow-up (P<.0001). Average American Shoulder and Elbow Surgeons (ASES) scores also significantly improved, from 40 points preoperatively to 66 points at last follow-up (P<.0001), the authors reported.

Additionally, mean pain scores measured using the Visual Analog Scale (VAS) significantly improved from 62 points preoperatively to 20 points at final follow-up, the authors noted.

Of the 58 stems included in the study, 24 shoulders showed radiolucent lines adjacent to the stem at last follow-up, with an average maximum thickness of 0.47 mm among these stems.

Also at last follow-up, neutral angles were noted for 20 components, 14 cases had valgus angles averaging 2.7° and 24 components had varus angles averaging 2.9°, according to the study.

No cases showed component subsidence, the authors noted.

No correlations were found between the maximum thickness of radiolucent lines and ASES scores, SST scores or improvement in VAS scores, although patients without lucencies had higher VAS scores, according to the study.

For more information:
Wirth MA, Lim M, Southworth C, et al. Compaction bone grafting in prosthetic shoulder arthroplasty. J Bone Joint Surg Am. 2007;89-A:49-57.