Long-Term Clinical and Radiographic Outcomes of Total Shoulder Arthroplasty in Patients Under Age 60

These authors performed a retrospective analysis of total shoulder arthroplasties (TSA) performed at a single institution between December 1992 and September 2014 by a fellowship-trained orthopedic surgeon. Patients were included if they underwent a TSA before age 60 with a minimum follow-up of 10 years.

29 patients (34 shoulders) were included; mean age of patients was 54.4 ± 5.5 years (range, 35.5-59.8 years) with a mean follow-up of 16.1 ± 4.5 years (range, 10.0-26.1 years). Indications for TSA included osteoarthritis (n=25), rheumatoid arthritis (n=2), post-traumatic arthritis (n=4), and avascular necrosis (n=3).

All surgeries were performed by a single surgeon using a single implant: the Bigliani/Flatow Complete Shoulder Solution TSA. Glenoid deformity was managed with eccentric reaming when necessary. No augmented glenoid components or bone augmentation was used.

They found that TSA significantly improved forward elevation from 119 to 146º. external rotation from 21 to 52º, and internal rotation from L5 to L1.

TSA significantly increased ASES scores from 32 to 64 and SST scores from 3 to 7, while reducing VAS pain scores from 7 to 3.

Radiographically, there was no significant change in mean lateral humeral offset (13 vs. 10) or acromiohumeral interval (20 vs. 16) between immediate postoperative and final follow-up radiographs.

Aseptic glenoid loosening developed in 6 cases, two of which were asymptomatic. Four patients experienced symptomatic aseptic glenoid loosening and underwent arthroscopic glenoid removal at an average of 11.6 years after surgery. Two of these patients ultimately underwent reverse total shoulder arthroplasty (RTSA) at an average of 27.3 months after glenoid component removal for persistent shoulder pain.

Two additional patients underwent an RTSA; one for a full-thickness subscapularis tear 14.1 years postoperation and another for aseptic glenoid loosening 13.0 years postoperation.

Prosthesis survivorship was calculated as 97.1% at 10-years, 85.4% at 15-years, and 80.1 % at 20-years.

Comment:

(1) The retrospective study does not present the total number of TSAs performed on individuals under the age of 60 performed by this busy arthroplasty surgeon during the 22 year study period from 1992 to 2014. Thus the percent of potentially eligible cases that were included in the study is not known. How does this sample reflect the outcome of all TSAs performed on individuals under the age of 60? What is the effect of non-response bias on the conclusions?

(2) The last decade has seen many changes in TSA indications, techniques, implants and followup methods. To what extent are these outcomes relevant to current practice?

(3) While the article reports "no significant change" in the measures of humeral offset or acromiohumeral interval, what is the statistical power of this conclusion with the small sample size?

As the field of shoulder arthroplasty moves forward, it is apparent that clinical investigators should prospectively enroll patients in their studies, assure that all baseline data and treatment details are collected, strive to capture outcome data on the highest percentage of the patients enrolled, and report the percentage patients enrolled who were not included in the final analysis (and why).

Codman: "Every hospital should follow every patient it treats, long enough to determine whether or not the treatment has been successful..."

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