ABSTRACT
BACKGROUND: While most anatomic TSA stems allow some intra-operative adjustments, the default configuration assumes that head offset is directly proportional to stem diameter. Some authors reported that humeral head diameter is proportional to intra-medullary canal width and humeral head offset, but none investigated the direct relationship between head offset and endosteal measurements. The purpose of the study was to determine whether global humeral head offset is proportional to intramedullary canal width at the distal metaphysis and proximal diaphysis. METHODS: We analyzed 100 Computed Tomography shoulder scans of patients aged 59.1 ± 20.5 with no signs of gleno-humeral arthritis nor humeral dysplasia. The width of the intramedullary diaphyseal canal was determined at four transverse sections 65, 70, 100 and 105 mm below the head center. The inter-observer agreement was excellent for intramedullary canal width (ICC = 0.96), head diameter (ICC = 0.97) and global head offset (ICC = 0.85). Correlations were analysed using Pearson's coefficients and multivariable regressions were performed to determine associations between head offset and five independent variables (gender, age, intramedullary canal width, head diameter). RESULTS: Global head offset was negatively correlated with head diameter (r = - 0.31, p = 0.002), but not correlated with intramedullary canal width (r = - 0.11, p = 0.282). Multivariable regression confirmed that global head offset was independently associated with head diameter (beta = - 0.15, p = 0.005), but not with intramedullary canal width (beta = 0.06, p = 0.431). CONCLUSIONS: The present study revealed that humeral offset is not correlated with intramedullary canal width. Implant manufacturers and shoulder surgeons should be aware of the subtle morphologic features, to enhance humeral stem design and restore native anatomy.
ABSTRACT
BACKGROUND: The aim of this study was to determine the clinical efficacy of minimally invasive endoscopic ulnar nerve release at midterm follow-up. METHODS: This was a retrospective, consecutive, single-center study. The inclusion criterion was presentation of the patient with isolated and stable cubital tunnel syndrome. The surgical technique described by Hoffmann and Siemionow in 2006 was used for all patients. The cubital tunnel syndrome was graded by Dellon's classification and scored as described by MacDermid and Grewal in 2013. RESULTS: Sixty patients underwent surgery (62 cubital tunnel operations). Fifty-three patients were included in the study. The mean follow-up was 17 months (6-34). In the preoperative period, according to Dellon's classification, 8 patients were grade 1, 29 patients were grade 2, and 16 patients were grade 3. After surgery, according to the MacDermid score, 45 patients (84.9%) had good or excellent results, 6 (11.3%) had moderate results, and 2 (3.8%) had poor results. The mean preoperative score was 103.1 (25-181), and the mean postoperative score was 26.3 (0-135). By comparison with standard surgical technique, the endoscopic technique appears to be reliable with a similar success rate and functional improvement. The advantages are the minimally invasive portion of the surgical technique. Endoscopic control allowed complete release of the ulnar nerve with few complications. CONCLUSION: The endoscopic technique as described by Hoffman et al had similar efficacy to open surgical techniques with the advantage of being minimally invasive.
