. Mixed Component Reverse Total Shoulder Arthroplasty Dissociation of Cemented Humeral Cup from Humeral Stem. OrthopaedicsOne Cases. In: OrthopaedicsOne - The Orthopaedic Knowledge Network. Created Jul 01, 2012 19:23. Last modified Jul 03, 2012 12:42 ver.5. Retrieved 2019-04-25, from https://www.orthopaedicsone.com/x/EwJBBQ.
Reverse total shoulder arthroplasty (RTSA) was introduced in 1987 as a treatment option for patients with symptomatic glenohumeral arthritis and rotator cuff deficiency, but was not used extensively until the late 1990s. In 2007, Levy et al 5 were the first to report the use of RTSA as a successful treatment for failed hemiarthroplasty, with 79% of patients rating outcomes at a level of satisfactory or better.
Despite these promising results, revision of failed hemiarthroplasty to RTSA can be a challenging procedure for many orthopaedic surgeons. In particular, humeral component extraction can be a source of complication, particularly with a well-fixed component.10 Common methods of humeral component extraction include the use of specialized extraction equipment, a medial window, an anterior window, or a longitudinal osteotomy, depending on the patients situation. Also, recently developed techniques called “vertical humeral osteotomy” and “longitudinal split osteotomy” have been proposed to remove both cemented and noncemented humeral components, and have been cited as successful thus far by the institution of origin.3,8,9 A variety of humeral stem extraction techniques are available to minimize the risk of complications associated with revision surgery.
To our knowledge this is the first report describing the intraoperative alteration and mating of shoulder arthroplasty components from different manufacturers in an attempt to avoid extraction of the humeral component, which leads to subsequent component failure.
An 89-year-old female (5'9", 118 lbs, 23.8 kg/m2 BMI) fell and sustained a significantly comminuted three-part fracture of the right proximal humerus. A shoulder hemiarthroplasty was subsequently performed without complication at an outside institution.
Approximately 6 months postoperatively, the patient elected to undergo revision surgery. The failed hemiarthroplasty was converted to a RTSA at the same outside institution and the patient’s postoperative course was reported to be uncomplicated by the treating physician.
Six months following this conversion, the patient sustained a fall at her nursing home and was admitted to our institution. Radiographs obtained at the time of admission demonstrated component dissociation of the humeral socket from the humeral stem (Figure 1). Review of the patient’s medical records from the original treating hospital confirmed that components from different manufacturers had been mated in an unconventional method. The humeral stem originated from one manufacturer (Epoca Shoulder System, Synthes, West Chester, PA) and the humeral socket originated from another manufacturer (Reverse Shoulder Prosthesis, DJO Surgical, Austin, TX).
The operative report from the revision surgery noted the humeral stem from the original Synthes System hemiarthroplasty was solidly fixed and could not be removed. The head and the adaptor of the Synthes stem component were removed, leaving a female end at the proximal tip of the humeral stem. This female end was then enlarged with a Midas Rex diamond tip bur to accept the morse taper male end of a reverse shoulder humeral socket from DJO surgical. The humeral socket was then cemented into the humeral stem and the shoulder was reduced.
At the time of admission to our institution, the patient’s medical condition had significantly deteriorated. Most notably, the patient suffered a cerebrovascular accident that rendered her essentially aphasic, noncommunative, and with significant contractures of the right upper and lower extremities. Based on the patient's significant medical comorbidities and the family's desires, a nonoperative treatment plan was deemed most appropriate.