Among patients with RA undergoing shoulder arthroplasty, the overall rate of early adverse events was 3.12%, of which the most common early adverse events were urinary tract infections (1.8%), acute kidney injury (0.66%), and pneumonia (0.38%) (Table 3). As compared with patients without a diagnosis of RA undergoing shoulder arthroplasty, there were no significant differences in the overall and individual rates of early adverse events (Table 3).
Table 3. A Comparison of Early Adverse Events, Length of Stay, and Cost Between Patients With and Without Rheumatoid Arthritis (RA) Undergoing Shoulder Arthroplasty
Comparison of Early Adverse Event Rates | |||||
Non-RA Patients | RA Patients | Multivariate Logistic Regression | |||
Odds Ratio | P-Value | ||||
Overall adverse event rate | 3.02% | 3.12% | 1.0 | 0.83 | |
Specific adverse event rate | |||||
Death | 0.08% | 0.05% | 0.9 | 0.91 | |
Acute kidney injury | 0.85% | 0.66% | 0.9 | 0.59 | |
Cardiac arrest | 0.05% | 0.05% | 1.3 | 0.70 | |
Thromboembolic event | 0.01% | 0.00% | - | - | |
Myocardial Infarction | 0.22% | 0.06% | 0.4 | 0.17 | |
Peripheral nerve injury | 0.08% | 0.11% | 1.5 | 0.45 | |
Pneumonia | 0.47% | 0.38% | 0.9 | 0.70 | |
Sepsis | 0.08% | 0.08% | 1.3 | 0.62 | |
Stroke | 0.07% | 0.05% | 0.9 | 0.93 | |
Surgical site infection | 0.09% | 0.13% | 1.4 | 0.52 | |
Urinary tract infection | 1.44% | 1.80% | 1.1 | 0.46 | |
Wound dehiscence | 0.01% | 0.05% | 3.6 | 0.09 | |
Comparison of Length of Stay and Hospital Charges | |||||
Non-RA Patients (percent) | RA Patients (percent) | Multivariate Linear Regression | |||
Beta | P-Value | ||||
Length of staya | 2.3±2.0 | 2.4±1.6 | +0.1 | 0.002 | |
Hospitalization costb | 14,826±8,336 | 14,787±7,625 | +93 | 0.59 | |
aReported in days. bReported in 2011 US dollars, adjusted for inflation.
The mean length of stay following shoulder arthroplasty in RA patients was 2.4 ± 1.6 days, and the mean hospitalization cost was $14,787 ± $7625 (Table 3). As compared with non-RA patients undergoing shoulder arthroplasty, there were no significant differences in the mean hospitalization costs; however, non-RA patients had a significantly shorter length of stay by 0.1 days (P = .002) (Table 3).
DISCUSSION
In this study, we observed that the utilization of shoulder arthroplasty in patients with RA increased significantly in the decade from 2002 to 2011, largely related to a rise in TSA. Interestingly, we also observed a corresponding rise in the proportion of RA patients undergoing shoulder arthroplasty with a diagnosis of rotator cuff disease, and we believe that this may partly account for the recent increase in the use of the reverse TSA in this patient population. Additionally, we found shoulder arthroplasty in RA patients to be safe in the early postoperative period, with no significant increase in cost as compared with patients undergoing shoulder arthroplasty without a diagnosis of RA. Although we did observe a significant increase in length of stay among RA patients as compared with non-RA patients, the absolute difference was only 0.1 days, and given the aforementioned similarities in cost between RA and non-RA patients, we do not believe this difference to be clinically significant.
It has been theorized that the utilization of TJA in RA patients has been decreasing with improvements in medical management; however, this is largely based upon literature pertaining to lower extremity TJA.2 On the contrary, past research pertaining to the utilization of shoulder arthroplasty in RA patients has been highly variable. For instance, a Swedish study demonstrated a statistically significant decrease in admissions associated with RA-related upper limb surgery and a stable rate of shoulder arthroplasty between 1998 and 2004.7 Similarly, a Finnish study demonstrated that the annual incidence of primary joint arthroplasty in RA patients had declined from 1995 to 2010, with a greater decline for upper-limb arthroplasty as compared with lower-limb arthroplasty.8 Despite these European observations, Jain and colleagues9 reported an increasing rate of TSA among RA patients in the US between the years 1992 and 2005. In this study, we demonstrate a clear increase in the utilization of shoulder arthroplasty among RA patients between 2002 and 2011. What was most striking about our observation was that the rise in utilization appeared to be driven by an increase in TSA, whereas the utilization of HA decreased over time. This change in practice likely reflects several factors, including the multitude of studies that have demonstrated improved outcomes with anatomic TSA as compared with HA in RA patients.10-14
Perhaps the most interesting aspect of our data was the recent exponential rise in the utilization of the reverse TSA. Despite improved outcomes following TSA as compared with HA in RA patients, these outcomes all appear to be highly dependent upon the integrity of the rotator cuff.10 In fact, there is evidence that failure of the rotator cuff could be as high as 75% within 10 years of TSA in patients with RA,15 which ultimately could jeopardize the long-term durability of the TSA implant in this patient population.11 For this reason, interest in the reverse TSA for the RA patient population has increased since its introduction in the US in 2004;16 in fact, in RA patients with end-stage inflammatory arthropathy and a damaged rotator cuff, the reverse TSA has demonstrated excellent results.17-20 Based upon this evidence, it is not surprising that we found an exponential rise in the use of the reverse TSA since 2010, which corresponds to the introduction of an ICD-9 code for this implant.21 Prior to 2010, it is likely that many implanted reverse TSAs were coded as TSA, and for this reason, we believe that the observed rise in the utilization of TSA in RA patients prior to 2010 may have been partly fueled by an increase in the use of the reverse TSA. To further support this theory, there was a dramatic decrease in the use of anatomic TSA following 2010, and we believe this was related to increased awareness of the newly introduced reverse TSA code among surgeons.
Another consideration when examining the utilization of shoulder arthroplasty in RA patients is its versatility in managing different disease states, including rotator cuff disease. As has been documented in the literature, outcomes of rotator cuff repair in RA patients are discouraging.22 For this reason, it is reasonable for surgeons and patients with RA to consider alternatives to rotator cuff repair when nonoperative management has failed to provide adequate improvement in symptoms. One alternative may be shoulder arthroplasty, namely the reverse TSA. In this study, we observed a significant increase in the rate of diagnosis of rotator cuff disease among RA patients undergoing shoulder arthroplasty from 2002 to 2011 (9.7% in 2002 to 15.2% in 2011, P < .001), and it is our belief that the simultaneous increase in the diagnosis of rotator cuff disease and use of TSA is not coincidental. More specifically, there is likely an emerging trend among surgeons toward using the reverse TSA to manage rotator cuff tears in the RA population, rather than undertaking a rotator cuff repair that carries a high rate of failure. Going forward, there is a need to not only identify this trend more clearly but to also compare the outcomes between reverse TSA and rotator cuff repair in the management of rotator cuff tears in RA patients.
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