Discovery® elbow system arthroplasty: results of 10-year follow-up.

BACKGROUND: The semi-constrained Discovery® Elbow System (LimaCorporate, San Daniele del Friuli, Italy) allows varus-valgus laxity of 7° [8]. It has been reported to provide good pain relief and increased range of motion [5, 9] on mid-term follow-up. The aim of the study was to evaluate long-term outcomes of total elbow arthroplasty using the Discovery® Elbow System (LimaCorporate, San Daniele del Friuli, Italy). MATERIALS AND METHODS: The Mayo Elbow Performance Score (MEPS) and elbow range of motion (ROM) were assessed. Plain radiographs were obtained to assess radiolucency in the humerus and ulna. The data were extracted from electronic patient records. RESULTS: During the follow-up period of 105.4 (range 24.6-179.9) months, 132 patients (153 elbows) underwent surgery. The cause of surgery was rheumatoid arthritis in 105 (71%) cases, posttraumatic or primary arthritis in 17 (13%) and fracture in 10 (6%) patients. The total MEPS increased on average by 35.0 points. Elbow extension deteriorated by 5.0°. Respectively, flexion improved by 10.0° and pronation by 5.0°. The difference in supination was 0.0°. Pain severity improved by 2.5 points in motion and by 5.5 points at rest. During follow-up, 24 (16%) patients needed revision surgery. The most common cause for revision was periprosthetic fracture. Radiolucent lines were seen in all zones in both the ulna and the humerus. The Kaplan-Meier survival at 5 years was 88% and 79% at 10-14 years. CONCLUSION: The Discovery® Elbow System provides good results in ROM and pain relief of the elbow. The revision rate was relatively high (16% of patients). LEVEL OF EVIDENCE: IV.

The effect of body mass index on the spread of spinal block in patients with rheumatoid arthritis.

PURPOSE: Body mass index (BMI) has a significant effect on the spread of sensory spinal block in rheumatoid patients. We tried to achieve the same spread of spinal block for patients in three different BMI groups and, on the basis of the results from a preliminary study, used a simple method feasible for clinical practice. We hypothesized that BMI-related inverse dosing of plain bupivacaine according to low, normal, and high BMI would result in no difference in block extent. METHODS: Together 75 patients with seropositive rheumatoid arthritis were included in three equal-sized groups according to BMI: low (<23 kg/m(2)), normal (23-28 kg/m(2)), and high (>28 kg/m(2)). Spinal anesthesia was induced with plain bupivacaine using doses 3.3, 3.0, and 2.7 ml, respectively. The spread of sensory block was recorded 30 min after injection of bupivacaine by use of a pin-prick test and a cold ice-filled container. RESULTS: Spreads of sensory block were different in low, normal, and high BMI groups (mean (SD); 14.0 (2.6), 14.5 (2.5), and 16.3 (2.5) dermatomes, respectively, P = 0.006) because of greater block extent in the high-BMI group. CONCLUSIONS: Despite three-step dosing of plain bupivacaine inversely related to BMI (low, normal, or high), comparable block extent was not achieved because of greater spread in the high-BMI group. Adjustment of plain bupivacaine dose according to BMI could be used to achieve a more predictable spread of spinal block, but further reduction of dose is needed in patients with high BMI.