Stem anteversion is not affected by proximal femur geometry in robotic-assisted total hip arthroplasty.

BACKGROUND: In the present study, the surgeon aimed to align the stem at 5° to 25° in anteversion. The robotic technology was used to measure stem anteversion with respect to proximal femur anteversion at different levels down the femur. METHODS: A total of 102 consecutive patients underwent robotic-arm-assisted total hip arthroplasty (RTHA). 3D CT-based preoperative planning was performed to determine femoral neck version (FNV), posterior cortex anteversion (PCA), anterior cortex anteversion (ACA), and femoral metaphyseal axis anteversion (MAA) at 3 different levels: D (10 mm above lesser trochanter), E (the midpoint of the planned neck resection line) and F (head-neck junction). The robotic system was used to define and measure stem anteversion during surgery. RESULTS: Mean FNV was 6.6° (SD: 8.8°) and the mean MAA was consistently significantly higher than FNV, growing progressively from proximal to distal. Mean SV was 16.4° (SD: 4.7°). There was no statistically significant difference (P = 0.16) between SV and MAA at the most distal measured level. In 96.1% cases, the stem was positioned inside the 5°-25° anteversion range. CONCLUSIONS: Femoral anteversion progressively increased from neck to proximal metaphysis. Aligning the stem close to femoral anteversion 10 mm above the lesser trochanter often led to the desired component anteversion.

Evaluation of Native Femoral Neck Version and Final Stem Version Variability in Patients With Osteoarthritis Undergoing Robotically Implanted Total Hip Arthroplasty.

BACKGROUND: Combined anteversion in total hip arthroplasty influences both dislocation risk and range of motion. One of its components, stem version (SV), could be dictated by many factors, from native femoral anatomy to stem geometry and surgeon's choice. In the present multicenter study, robotic technology was used to assess the influence of native femoral version on final SV and combined anteversion using a straight, uncemented stem. METHODS: Three hundred sixty-two patients undergoing total hip arthroplasty were enrolled from 3 different orthopedic centers from 2012 and 2016. All patients underwent computed tomography planning with measurement of femoral neck version (FNV) and intraoperative measurement of stem version (SV), acetabular component version (AV), and combined version (CV) with robotic instrumentation. RESULTS: Mean FNV was 5.0° ± 9.6°, and SV was 6.4° ± 9.7°. The average difference between FNV and SV was 1.6° ± 9.8°. A moderate correlation was found between FNV and SV (R = 0.48, P < .001). SV was between 5° and 20° in 174 patients (48%). Mean CV was 28.2° ± 7.9°. A strong correlation was found between SV and CV (R = 0.89, P < .001). A significant difference in SV was found between the 3 centers (P < .001). CV was <25° in 109 patients (30.1%). Relative risk of CV < 25° was 8.6 times greater with SV < 5° (P < .001). CONCLUSION: With the use of an uncemented, single-wedge, straight stem, SV is highly variable. Despite being moderately correlated with native FNV, SV can be partially influenced by the surgeon. A low SV could be hardly corrected, bringing high risk of low CV.

Fixation of winged scapula in facioscapulohumeral muscular dystrophy.

OBJECTIVE: To verify if stabilizing the scapulothoracic joint without arthrodesis could lead to functional improvement of shoulder range of motion and clinical improvement of winged scapula, we incorporated four additional patients into our previous analysis to determine if the results obtained were long lasting, and to compare this fixation with the other techniques described in the literature, balancing the benefits with the complications. DESIGN: A retrospective study. PARTICIPANTS: Thirteen patients with bilateral winged scapula affected by facioscapulohumeral muscular dystrophy. Nine of these patients had been analyzed in our previous study. METHODS: Patients were operated on by bilateral fixing of the scapula to the rib cage using metal wires without arthrodesis (scapulopexy). RESULTS: All patients experienced improvement in active range of motion of the shoulder and all of them had clinical improvement with complete resolution of the winged scapula. In all twenty-six surgical interventions of scapulopexy, a stable and long-lasting fixation of the scapula to the rib cage was achieved. The complications strictly associated to the surgical technique encountered were one pneumothorax, which was resolved spontaneously, and one wire breakage without trauma. Average follow-up was 10 years (range, 3 to 18 years). CONCLUSION: The scapulopexy used in this extended series of patients consisted of repositioning the scapula and fixing it to four ribs by using metal wires without performing arthrodesis. This technique has a low rate of complications, is reproducible, safe and effective, resulting in clinical and functional improvement.

Surgical treatment of neck hyperextension in duchenne muscular dystrophy by posterior interspinous fusion.

STUDY DESIGN: Seven patients affected by Duchenne muscular dystrophy with neck hyperextension or poor head control in extension have undergone surgery consisting of posterior cervical interspinous fusion. OBJECTIVE: To report the results of surgical treatment of neck hyperextension executed simultaneously with the correction of the thoracolumbar scoliosis. SUMMARY OF BACKGROUND DATA: A severely progressive deformity of the spine in patients affected by DMD can involve also the cervical spine presenting a rigid neck hyperextension or poor head control in extension, forcing the patients to assume awkward compensating postures in order to look straight ahead, worsening significantly their quality of life. METHODS: The procedure consisted of a posterior approach to the cervical spine, correction of the hyperextension by releasing the fibrotic muscles and ligaments, and stabilization with bone grafts driven into the interspinous spaces, to achieve solid fusion. RESULTS: No surgical complications were observed, and fusion was achieved in all patients. The mean angle between C2-C7 decreased from an average of 29.8 degrees (7 degrees -56 degrees) before surgery, to an average of 18.5 degrees (6 degrees-30 degrees) at 1 year of follow-up. Range of motion between C1-C2 was preserved. CONCLUSIONS: Surgical treatment of neck hyperextension in these patients contributes to a better sitting position, to an easier nursing, to a better appearance.