Proximal ingrowth coating decreases risk of loosening following uncemented shoulder arthroplasty using mini-stem humeral components and lesser tuberosity osteotomy.
BACKGROUND
Mini-stem humeral component (MSHC) use during total shoulder arthroplasty (TSA) provides bone preservation and ease of revision. MSHCs rely solely on proximal metaphyseal fixation; some early reports have demonstrated an unacceptably high rate of early loosening. To our knowledge, no study analyzing the effect of proximal porous coating on MSHCs has been performed.


METHODS
We performed a retrospective review of consecutive patients who underwent anatomic TSA using coated or uncoated MSHCs with minimum 2-year follow-up. Postoperative radiographs were assessed for risk of or frank stem loosening, subsidence, and presence of radiolucencies. Range of motion, outcome scores (visual analog scale pain, American Shoulder and Elbow Surgeons, and Single Assessment Numeric Evaluation), and any complications were noted.


RESULTS
We analyzed 68 shoulders with a mean follow-up of 27.3 months (range, 24-50 months). Of these, 34 had proximal coating and 34 were uncoated. In the coated group, no stems loosened, 1 (2.9%) subsided, and 7 (20.6%) developed radiolucencies. In the uncoated group, 1 stem (2.9%) became aseptically loose (requiring revision after 26 months), 7 (20.6%) were judged at risk of loosening (2 because of subsidence), and 15 (44.1%) developed radiolucencies. There was also an increased risk of proximal medial humeral radiolucencies among uncoated MSHCs. There were no significant differences in final range of motion or outcome scores.


CONCLUSIONS
MSHC use is appropriate for TSA, achieving desired pain relief and functional improvement. Overall, component loosening appears uncommon at early follow-up; however, uncoated stems appear to be at greater risk of loosening and developing radiolucencies. Selecting an MSHC with proximal porous coating may decrease the risk of implant-related complications.
Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
Michael P
MP
Morwood
Southern Maryland Orthopaedic and Sports Medicine Center, Leonardtown, MD, USA.
Peter S
PS
Johnston
Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA. Electronic address: grant.garrigues@duke.edu.
Grant E
GE
Garrigues
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006811:Humerus / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D010147:Pain Measurement; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D011184:Postoperative Period; D011475:Prosthesis Failure / Q000209:etiology; D011859:Radiography; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012307:Risk Factors; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D020069:Shoulder Pain / Q000209:etiology; D000072227:Shoulder Prosthesis; D013499:Surface Properties
Shoulder; arthroplasty; hardware failure; loosening; outcomes; proximal coating; stem