Does glenohumeral offset affect clinical outcomes in a lateralized reverse total shoulder arthroplasty?

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) exhibits high rates of success and low complication rates. rTSA has undergone numerous design adaptations over recent years, and lateralization of implant components provides theoretical and biomechanical benefits in stability and range of motion (ROM) as well as decreased rates of notching. However, the magnitude of implant lateralization and its effect on these outcomes is less well understood. The purpose of this study was to evaluate how increasing glenohumeral offset affects outcomes after rTSA, specifically in a lateralized humerus + medialized glenoid implant model. METHODS: Primary rTSA using a lateralized humeral + medialized glenoid implant model performed at a single academic institution between 2012 and 2018 were retrospectively reviewed. Patient-reported outcome (PRO) parameters and clinical outcomes including ROM were evaluated both pre- and postoperatively. Pre- and postoperative radiographs were analyzed for measurement of glenohumeral offset, defined as the acromial-tuberosity offset (ATO) distance on the anteroposterior radiograph. RESULTS: A total of 130 rTSAs were included in the analysis, with a mean follow-up of 35 mo. The mean postoperative absolute ATO was 16 mm, and the mean delta ATO (difference from pre- to postoperatively) was 4.6 mm further lateralized. Among all study patients, improvements in all ROM parameters and all PROs were observed from pre- to postoperative assessments. When assessing for the effects of lateralization on these outcomes, multivariate analysis failed to reveal a significant effect from the absolute postoperative ATO or the delta ATO on any outcome parameter. CONCLUSIONS: rTSA using a lateralized humeral + medialized glenoid implant model exhibits excellent clinical outcomes in ROM and PROs. However, the magnitude of lateralization as measured radiographically by the ATO did not significantly affect these outcomes; patients exhibited universally good outcomes irrespective of the degree of offset restoration.

Mortality and Conversion Rates to Below-Knee or Above-Knee Amputation After Transmetatarsal Amputation.

INTRODUCTION: The purpose of this study was to identify associated risk factors for complications, need for a higher level of amputation such as below-knee amputation (BKA) or above-knee amputation (AKA), and mortality after transmetatarsal amputation (TMA). METHODS: We identified 265 patients who underwent 286 TMA procedures between June 2002 and July 2016. Medical records were reviewed for revision surgery and amputation. Mortality was verified using the National Death Index. We identified and documented potential risk factors including diabetes, hemoglobin A1c level, end-stage renal disease, cardiovascular disease, peripheral vascular disease, history of revascularization, contralateral amputation, and neuropathy. Sixty-eight percent were male, the mean age was 56.9 years (SD 12.8; range 24.1 to 92.1), and the median body mass index was 28.6 (interquartile range, 24.5 to 33.1). RESULTS: Twenty-seven percent of the patients required a subsequent BKA or AKA after the index TMA surgery. The results of a multivariable model indicated that women (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.716 to 7.672), patients aged 57 to 64 years (OR, 0.17; 95% CI, 0.06 to 0.51), and patients with a history of revascularization (OR, 7.06, 95% CI, 2.86 to 17.44) had markedly higher odds than the relevant comparison groups. Forty percent of the patients died after the index TMA at a median of 27 months. After adjusting for all patient factors, history of end-stage renal disease (OR, 2.2; 95% CI, 1.206 to 4.014) and cardiovascular disease (OR, 2.879; 95% CI, 1.615 to 5.131) remained markedly associated with mortality after TMA. DISCUSSION: There are high rates of additional amputation after nontraumatic TMA and a high mortality rate. Surgeons should set realistic expectations with patients considered for TMA and identify risk factors, which may guide treatment. Treatment is multidisciplinary, requiring attention to surgical details, correction of vascular deficiency or contracture when present, and perioperative medical optimization. LEVEL OF EVIDENCE: IV.