Abstract
Introduction
A better understanding of the rate of improvement associated with aTSA and rTSA is critical to establish accurate patient expectations for treatment to reduce pain and restore function; more realistic patient expectations pre-operatively may lead to greater patient satisfaction post-operatively. To this end, this study quantifies the rate of improvement in outcomes of aTSA and rTSA using 5 different scoring metrics for 1641 patients with one platform shoulder arthroplasty system.
Methods
1641 patients (mean age: 69.3yrs) were treated by 14 orthopaedic surgeons using one platform shoulder system (Exactech, Inc). 729 patients received aTSA (65.3yrs; 384F/345M) for treatment of degenerative arthritis and 912 patients received rTSA (72.5yrs; 593F/319M) for treatment of CTA/RCT/OA. Each patient was scored pre-operatively and at various follow-up intervals (3 months, 6months, annually, etc) using the SST, UCLA, ASES, Constant, and SPADI metrics; active abduction, active forward flexion, and active/passive external rotation were also measured. 4439 total follow-up reports were analyzed (1851 and 2588 rTSA). Improvements in outcome using each metric score were calculated and normalized on a 100 point scale. The rate of improvement was analyzed using a 40 point moving filter treadline and with a 3rd order polynomial treadline over the entire range of follow-up.
Results
aTSA and rTSA outcomes with each scoring metric improved in the majority of patients, where less than 5% of reports had negative improvement in each metric after 6 months follow-up. (Figure 1) Similarly, motion improved in the majority of aTSA patients, where less than 8% of reports had negative improvement after 6 months follow-up. rTSA patients had a higher percentage of reports with negative improvement in motion after 6 months followup, where <12% of patients had negative improvement in active abduction and forward flexion while <20% patients had negative improvement in active external rotation. The pattern of improvement for each metric was similar for both aTSA and rTSA, where the SST metric demonstrated the largest improvement and the Constant metric demonstrated the smallest improvement for aTSA (Figure 2) and rTSA (Figure 3). Differences in improvement between aTSA and rTSA were observed, with rTSA associated with a larger magnitude of improvement in both the Constant score and active forward flexion and with aTSA associated with larger improvement in external rotation. Finally, full improvement was reached between 12 and 24 months for both aTSA and rTSA patients where the rate of improvement associated with rTSA patients was generally 30% larger than aTSA patients during the first 12 months.
Discussion and Conclusions
This database analysis of over 1600 patients demonstrates the reliability of improvements in outcomes achieved with both aTSA and rTSA using a single platform shoulder system. Future work should attempt to better understand the impact of pre-operative diagnosis, patient age/gender/BMI, and also the role of rehabilitation on the rate of improvement with each prosthesis type; additional follow-up time is required to confirm these results.
