The association of elevated body mass index (BMI) with complications and outcomes
following anatomic total shoulder arthroplasty: a systematic review
These authors conducted a systematic review is to summarize the correlation between elevated body mass index (BMI) and the prevalence of perioperative complications and clinical outcomes following anatomic total shoulder arthroplasty (aTSA).
11 studies were included - 9 studies reported solely on perioperative complications, 1 study solely on functional outcomes, and 1 study on bothbcomplications and outcomes following aTSA.
Most studies were found to have low methodological quality.
The authors found no significant association between elevated BMI and overall perioperative medical and surgical complications, surgical site infection (SSI), re-operation without revision, aseptic revision, periprosthetic fracture, intraoperative blood loss, need for blood transfusion, 90-day readmission, absolute hospital LOS or short-term mortality.
They did find an increased risk for overall revision following aTSA and need for extended hospital LOS in patients with elevated BMI.
Comment: This analysis was compromised by the low quality of the studies evaluated. One of the challenges in trying to relate BMI to surgical outcomes is that the relationship may well be bimodal: individuals with low BMI may be malnourished with its associated risks for fracture and infection while individuals with hi BMI may be at increased risk for falls and extended hospital stay.
Here's another article on the topic:
These authors identified 1520 patients having primary anatomic (aTSA) arthroplasty and 2054 patients having primary reverse total shoulder arthroplasty with a minimum follow-up of 2 years (mean 5 years). All patients received the same platform shoulder prosthesis.
Patients were stratified according implant type (anatomic or reverse), and further stratification was based on patient BMI, with obese patients having a BMI ≥ 30 kg/m2 and non-obese patients with a BMI <30 kg/m2.
41% of aTSA and 35% of rTSA were obese.
Obese patients in both groups reported higher preoperative and postoperative visual analog scale (VAS) pain scores (i.e. more pain) and less preoperative and postoperative ROM compared to non-obese patients.
Compared to non-obese patients, obese patients receiving an aTSA reported significantly worse postoperative SST, Constant, ASES, UCLA, and SPADI scores compared to non-obese patients, and those receiving rTSA reported significantly worse ASES and SPADI scores. However, these
22 differences did not exceed the minimal clinical important difference (MCID) or substantial benefit (SCB) criteria.
Statistically significant differences between obese and non-obese groups were not found to be clinically relevant given that the differences between the two groups with regards to VAS pain scores, ROM, and functional outcome scores did not exceed the MCID and SCB criteria in both the aTSA and rTSA groups.
Radiographic analysis 23 showed that in rTSA, obese patients had significantly less postoperative scapular notching and a lower scapular notching grade when compared to non-obese patients (P<0.05).
Obese patients had more comorbidities, greater intraoperative blood loss.
Overall complication rates were similar between obese and non-obese groups for both aTSA (7.6% vs. 8.4%; p = 0.57) and rTSA (3.4% vs. 3.9%), including rotator cuff tears, instability, infection, component loosening or failure, dislocation, liner dissociation, stress fracture, neurological complaints, and pain. Revision rates secondary to these complications were also similar between obese and non-obese groups for both aTSA (5.1% vs 5.9%) and rTSA (2.1% vs. 1.7%).
One of the more interesting findings in this study was that obesity seemed to protect patients against scapular notching and a higher notching grade. It seems possible that obesity limited adduction of the arm, reducing the contact between the medial edge of the humeral cup and the lateral scapular neck.
It is of interest to review some of the previous posts on the topic:
Is it safe to operate on patients with obesity?
Reverse total shoulder in obese patients - the 4 Ps
Malnutrition and arthroplasty outcomes
Shoulder arthroplasty - malnutrition increases risk
Adverse outcomes from total shoulder arthroplasty - the role of malnutrition
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