Exploring options in revision shoulder arthroplasty: Is a humeral stem necessary in revision reverse shoulders?

Abstract

Background

Traditionally, revision of stemmed arthroplasty necessitated the use of longer stem. In young patients, preservation of bone stock is crucial for possible further operations and prevent stress shielding and further bone loss.

Aim

To analyse the clinical and radiological outcomes of a series of patients who underwent revision shoulder arthroplasty, in whom the primary implant was stemmed total shoulder arthroplasty (TSA) and the implant for revision surgery was a stemless metaphyseal reverse TSA without a stem expanding to the humeral diaphysis.

Methods

Between 2010 and 2020, 10 patients (6M; 4F) underwent revision arthroplasty from long stemmed to short metaphyseal stemless rTSA due to pain and disfunction, implant instability and dislocation, cases of loosening and infection. The mean age at surgery was 67 ± 12.2 years. The stemmed implants revised were from different design and manufacturers (Biomet, Lima, Zimmer and Exactech). Impaction with bone graft substitute was used in all cases to fill the void on the humeral side together with antibiotic impregnated Calcium sulfate (Stimulan) beads, in infection cases or in suspicion of low-grade infection. Patients were assessed clinically with the Constant score (CS), Subjective Shoulder Value (SSV), Satisfaction and Radiologic assessment at 3, 6 and 12 months post-operatively, and annually thereafter.

Results

The mean follow-up was 69 months (24–144). Mean CS improved from 16.2 (4–35) to 72.1 (67–85), age/sex adjusted CS from 20.4 to 98.5 (p < 0.005). The mean SSV increased from 0.5/10 pre-operatively to 9/10 in the last follow-up. All the patients showed improvements in pain Range of motion and function. Post revision the metaphyseal stemless implants showed solid fixation in the humerus without any lucent lines, loosening, subsidence or evidence of stress shielding, with good new bone formation and filling of the intramedullary canal. In two patients, an implant tilt with perforation of the lateral cortex occurred in the first three weeks post-operatively due to weak cortical bone. The implants settled and remained stable in its new tilted position with conservative treatment, with new bone that was formed around the implants with solid long-term fixation.

Conclusions

Revision of a long-stemmed prosthesis with a stemless-metaphyseal one is feasible and a better option, if the metaphyseal cortical envelope is preserved on removal of the stemmed implant. Good outcome is achieved with good fixation of the stemless-metaphyseal implant and preservation of bone stock. However, implant design is pivotal in achieving immediate stability, resistance to torque and good stress distribution. The use of these implants in revision surgery enables surgeons to take ‘a step back’ in the patient's journey, preserve and ‘create’ more bone stock.