Impaction autografting: bone-preserving, secure fixation of a standard humeral component.
BACKGROUND
When fixed with bone ingrowth, a tight diaphyseal press fit, or cement, the humeral component of a shoulder arthroplasty may present problems of malposition, stress shielding, or periprosthetic fracture or difficulty with removal at revision arthroplasty. We have avoided the need for these fixation methods by using impaction cancellous autografting of the humeral stem, minimizing contact between the prosthetic stem and the humeral cortex. This study presents the radiographic survivorship of impaction-autografted humeral implants using component subsidence as the primary endpoint.


METHODS
We reviewed 286 primary anatomic shoulder arthroplasties having an average follow-up of 4.9 ± 2.7 years. Initial postoperative radiographs and minimum 2-year follow-up radiographs were evaluated by 3 observers to assess subsidence.


RESULTS
Two different implants (Humeral Replacement Prosthesis [HRP] and Global Advantage prosthesis) were used. Of 286 stems, 267 (93.4%) had not subsided. The Global Advantage prosthesis had a subsidence-free survival rate of 98.5% at 5 years. The stiffer-stemmed HRP used early during the study had a higher rate of subsidence compared with the currently used Global Advantage stem (hazard ratio, 5.6; P = .001). Radiolucent lines of 2 mm or greater were less common for the Global Advantage prosthesis than for the HRP in each of 7 zones (P < .001). Total shoulder arthroplasty was associated with a higher rate of subsidence compared with hemiarthroplasty (hazard ratio, 2.6; P = .12).


CONCLUSIONS
Impaction autografting provides a secure, durable, bone-preserving means of humeral component fixation in anatomic shoulder arthroplasty.
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Robert M
RM
Lucas
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Jason E
JE
Hsu
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Albert O
AO
Gee
The Mountain-Whisper-Light Statistics, Seattle, WA, USA.
Moni B
MB
Neradilek
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA. Electronic address: matsen@uw.edu.
Frederick A
FA
Matsen
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000072228:Arthroplasty, Replacement, Shoulder; D064592:Autografts; D016025:Bone Transplantation / Q000379:methods*; D005260:Female; D006801:Humans; D006811:Humerus / Q000637:transplantation; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012785:Shoulder Joint / Q000601:surgery*; D000072227:Shoulder Prosthesis; D055815:Young Adult
Shoulder arthroplasty; allograft; fixation; humeral component; impaction grafting; lucent lines; subsidence