Sunday, July 31, 2016

Young patients with end-stage shoulder arthritis: hemiarthroplasty or total shoulder?

Economic Decision Model Suggests Total Shoulder Arthroplasty is Superior to Hemiarthroplasty  in Young Patients with End-stage Shoulder Arthritis

These authors sought to estimate the outcomes (Neer criteria and quality-adjusted life-years (QALYs)), revision rates and relative costs of hemiarthroplasty (HA) and total shoulder arthroplasty (TSA) for glenohumeral arthritis in patients 30 to 50 years old using an economic decision model.

The model suggested that 
(1) HA as the initial treatment would result in 11.29 years  of satisfactory or excellent results per patient, average QALYs gained of 6.55, and 0.4 revisions during the patient's lifetime with direct reimbursements of $25,000 per patient.
(2) TSA as the initial treatment would result in 16.29 years of satisfactory or excellent results per patient, average QALYs gained of 7.96, and 0.3 revisions during the patient's lifetime with direct reimbursements of $23,700 per patient.

Comment: As discussed previously (see this link and this link), patients under the age of 50 years with glenohumeral arthritis severe enough to merit shoulder arthroplasty are significantly different than those over 50 years of age.

This is a most interesting study, suggesting that for comparable patients with comparable pathoanatomy, treatment of end-stage glenohumeral arthritis refractory to conservative treatment in patients 30 to 50 years old in the United States with TSA, instead of HA, might result in greater cost savings, avoid a substantial number of revision procedures, and result in greater years of satisfactory or excellent patient outcomes and greater QALYs gained.

However, the basis for the analysis might be questioned. For example, the annual failure rates and probability of satisfaction for HA and TSA used in the model were apparently obtained from an article published in 2004 using a Neer prosthesis which is no longer used (see this link, the abstract is reproduced below*). One might wonder if these values are applicable to the arthroplasties performed today. Furthermore, the patients having HA and TSA in the 2004 study that the authors used in their model were quite different as shown in our table made from the presented data. Notably, OA was a minority diagnosis.

Because of the lack of studies reporting measures of utilities in shoulder osteoarthritis or arthroplasty in young patients, the authors evaluated shoulder-specific outcome based on the modified Neer rating in addition to utilities derived from a study of older patients (see this link), which derived QALY values from aggregate analysis of the hip and knee arthroplasty literature.

We might wonder why a surgeon would choose a HA over a TSA for patients such as those included in the recently published model, especially since the surgeon's reimbursement is greater for the TSA. Possible reasons would include surgeon inexperience with TSA, a diagnosis of avascular necrosis, complex anatomy or shoulder tightness that precluded the use of a TSA, patient's desire to avoid the activity limitations typically imposed on individuals with TSAs, or concern about cuff deficiency. Interestingly, each of these reasons could contribute to inferior outcomes, higher revision rates, and greater costs for patients having HA in contrast to other patients having TSA.  In this study, it did not appear possible to control for these variables in the model design.

We suggest that the choice of procedure for an individual patient requires a balancing of patient, shoulder, surgeon, prosthetic and economic factors, with the needs of the patient and the type of pathology being the most important.

If one is really concerned about shoulder arthroplasty economics, perhaps it would be of greater  relevance to consider the economic effects of preoperative CT scans, ingrowth humeral stems, augmented or or metal backed glenoid components, and patient specific instrumentation.

*Seventy-eight Neer hemiarthroplasties and thirty-six Neer total shoulder arthroplasties were performed in patients aged 50 years or younger between January 1, 1976, and December 31, 1985. Sixty-two hemiarthroplasties and twenty-nine total shoulder arthroplasties with complete preoperative evaluation, operative records, and a minimum 15-year follow-up (mean, 16.8 years) or follow-up until revision were included in the clinical analysis. Sixteen patients died, and seven were lost to follow-up. All 114 shoulders were included in the survival analysis. There was significant long-term pain relief (P < .01) and improvement in active abduction (P < .01) and external rotation (P < .01) with both procedures. There was not a significant difference between total shoulder arthroplasty and hemiarthroplasty with regard to pain relief, abduction, or external rotation. Radiographs were available for 53 hemiarthroplasties and 25 total shoulder arthroplasties with a minimum 10-year follow-up. Humeral periprosthetic lucency was present more frequently after total shoulder arthroplasty (60%) compared with hemiarthroplasty (34%) (P = .0079). Glenoid erosion was present in 38 of 53 hemiarthroplasties (72%). Glenoid periprosthetic lucency was present in 19 of 25 total shoulder arthroplasties (76%). The results were graded by use of a modified Neer result rating system. Among the hemiarthroplasties, there were 6 excellent (10%), 19 satisfactory (30%), and 37 unsatisfactory results (60%). Among total shoulder arthroplasties, there were 6 excellent (21%), 9 satisfactory (31%), and 14 unsatisfactory results (48%). The estimated survival rate for hemiarthroplasty was 82% (95% CI, 74%-92%) at 10 years and 75% (95% CI, 64%-86%) at 20 years. The estimated survival rate for total shoulder arthroplasty was 97% (95% CI, 91%-100%) at 10 years and 84% (95% CI, 68%-98%) at 20 years. The data from this study indicate that there is marked long-term pain relief and improvement in motion with shoulder arthroplasty. However, there is a moderate rate of hemiarthroplasty revision for painful glenoid arthritis. Unsatisfactory result ratings were most commonly a result of motion restriction from soft-tissue abnormalities. Great care must be exercised, and alternative methods of treatment considered, before either hemiarthroplasty or total shoulder arthroplasty is offered to patients aged 50 years or younger.