Humeral head resurfacing, analysis of migration of the component on the humerus

Evaluation of periprosthetic bone mineral density and postoperative migration of humeral head resurfacing implants: two-year results of a randomized controlled clinical trial

These authors randomly allocated 32 patients (13 women), mean age 63 years (range, 39-82 years), with shoulder osteoarthritis to either a Copeland (n = 14) or Global C.A.P. (n = 18) humeral head resurfacing implant. Patients were monitored for 2 years with radiostereometry, dual-energy X-ray absorptiometry, Constant Shoulder Score, and the Western Ontario Osteoarthritis of the Shoulder Index.

At 2 years, total translation was 0.48 mm (standard deviation [SD], 0.21 mm) for the Copeland and 0.82 mm (SD, 0.46 mm) for the Global C.A.P. (P = .06).

The Copeland implant tended to migrate laterally and rotate into valgus, whereas the Global C.A.P. tended to translate distally and laterally.

Five (15%) of these implants were revised within the two year followup period. These revised implants demonstrated greater translation (0.58 mm (SD, 0.61 mm)) than non revised components (0.22 mm (SD, 0.17 mm)). The revised implants tended to translate in anterior, distal, and lateral

directions and to rotate into valgus. The reasons for revision included greater tuberosity fracture (1), pseudoparalysis (1), cuff rupture (2) and peri-implant arthritic changes (1). Four of these failures were revised to stemmed implants with apparently good results; one was revised to a reverse total shoulder.

While the bone mineral density was higher for the Copeland prosthesis, there was no difference in the clinical outcomes.

Comment: While considered to be more 'conservative' than a conventional stemmed humeral head replacement, the resurfacing humeral head replacement can present problems with migration after implantation as well as with positioning (as shown here and here).

The inclusion criteria were "individuals aged 18 to 85 years with shoulder osteoarthritis and cartilage defects involved on the humeral rather than on the glenoid side of the joint".  In our experience it is unusual to encounter osteoarthritis that involves only one side of the articulation.

At this point, we've yet to find an application for a resurfacing prosthesis in our practice.

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Shoulder arthritis articles from JSES - April - humeral head center, hemiarthroplasty for dysplasia, glenoid component failure

A reproducible and practical method for documenting the position of the humeral head center relative to the scapula on standardized plain radiographs. In this article our shoulder fellows Mercer and Saltzman describe a method by which the change in position of the prosthetic humeral head in relation to the scapula can be determined with time. This technique can be used to answer critical questions such as "What is the wear rate of plastic glenoid socket replacements with time after a total shoulder?" or "How does the bone of the glenoid hold up after a ream and run procedure?

Hemiarthroplasty for osteoarthritis in shoulder with dysplastic morphology suggests that replacing the humeral component alone, rather than performing a total shoulder replacement may be the preferable approach for managing shoulders that did not develop normally.

Results of a convex-back cemented keeled glenoid component in primary osteoarthritis: multicenter study with a follow-up greater than 5 years. In this paper our respected colleagues Walch and Boileau along with others provide a four center study of total shoulder replacement with a single component design of polyethylene glenoid. The clinical results were excellent with a 98% survivorship without surgical revision at 10 years.

When radiographic loosening was used as the endpoint, the survivorship was 100% at five years and 52% at 10 years.

The authors discovered that excessive glenoid reaming may be associated with an increased rate of glenoid component failure possibly because of the removal of the strong subchondral bone at the surface of glenoid. They also pointed out the need for long term followup using both X-rays and clinical criteria to evaluate the value of possible advances in the technique and components used in total shoulder arthroplasty.

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You may be interested in some of our most visited web pages including: shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery.

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