Fused hip conversion to total hip arthroplasty with the direct anterior approach: surgical technique on a regular surgical table under fluoroscopic guidance.

PURPOSE: Conversion of a fused hip to a total hip arthroplasty (THA) is technically challenging due to the loss of anatomical references. Here, a reproducible technique using the direct anterior approach (DAA) with a regular surgical table under fluoroscopic guidance is described, which has several advantages over traditional such as lateral or posterior approaches. METHODS: There were reported 11 cases of ankylosis hip that were converted to THA using the same surgical technique protocol. Clinical and radiographic outcomes were recorded at 3.2 years of follow-up. A detailed preoperative evaluation was performed, including a pelvis radiological evaluation and magnetic resonance image (MRI) to assess the integrity of the periarticular soft tissue and flexor muscles. RESULTS: The DAA has considerable advantages, such as allowing more precise targeting during surgery, avoiding the risk of pseudoarthrosis due to the absence of a trochanteric osteotomy, preserving the abductors, and allowing an easier-to-use of intraoperative fluoroscopy due to the supine position. Besides, the use of a standard table reduces surgical time and allows assessment of limb length, hip stability, and impingement in all planes in an intraoperative dynamic range, which decreases postoperative complications. CONCLUSION: Conversion from hip fusion to THA is a rare and complex procedure. The use of DAA with a standard table and fluoroscopy helps to avoid high complications since it allows a dynamic intra-operative examination of the range of motion to rule out impingements, reduces the risk of dislocation, and allows leg lengthening verification.

Cemented vs cementless stems for revision arthroplasties due to Vancouver B2 periprosthetic hip fracture.

PURPOSE: According to Vancouver classification, B2 type fractures are most often treated with removal of the loose stem and implantation of a long stem that bypasses the fracture site. However, there is a controversy about the stem fixation that should be used: cemented or cementless. Hence, this study aims to compare cemented and cementless stems in prosthetic revision due to Vancouver B2 (VB2) periprosthetic hip fracture. METHODS: A retrospective study was done including all the patients treated with stem exchange due to VB2 periprosthetic hip fracture in a tertiary hospital between 2015 and 2022. Patients were divided into two groups according to the stem fixation used: cemented or cementless. Functional outcomes, hospital stay, surgical time, complication rate, and mortality were compared between the two groups of patients. RESULTS: Of the 30 included patients, 13 (43.4%) were treated with cementless stems and 17 (56.7%) with cemented stems. There were no statistically significant differences in age, gender, anesthesia risk scale (ASA) or functional capacity prior to the intervention. Patients treated with cementless stems had a higher complication and reintervention rate than those treated with cemented stems: 62 and 45% versus 34 and 6% (p = 0.035; p = 0.010), respectively. Furthermore, in the group of cementless stems a higher proportion of non-union was found (53.8% vs. 17.6%; p = 0.037). Also, the hospital stay (33 vs. 24 days; p = 0.037) and the time to full weight-bearing (21 days vs. 9 days; p < 0.001) were longer in the cementless stem group. CONCLUSION: Cemented fixation in stem revision due to Vancouver B2 periprosthetic hip fracture could be an optimal option with faster recovery which could decrease the rate of complications and reintervention, without compromising the fracture healing and patient mortality. Thus, this option can be considered when an anatomical reduction can be obtained, especially in elderly patients with multiple comorbidities in which a less aggressive surgical option should be considered.

Buccal dental microwear texture and catarrhine diets.

OBJECTIVES: Two-dimensional dental microwear analyses on occlusal and nonocclusal enamel surfaces have been widely applied to reconstruct the feeding behaviors of extant primates and to infer ecological adaptations in fossil hominins. To date, analyses of dental microwear texture, using three-dimensional, Scale-Sensitive Fractal Analysis approaches has only been applied to occlusal surfaces. Here, for the first time, we apply this 3D proxy to buccal enamel surfaces of catarrhine primates of known feeding ecologies to assess the utility of nonocclusal microwear texture variables as indicators of dietary habits. MATERIALS AND METHODS: Buccal microwear texture attributes were collected from high-resolution second molar casts in a sample of seven extant African catarrhine taxa with differing dietary behaviors. A white-light confocal microscope with a 100× objective lens was used to record six microwear texture variables that assess complexity, anisotropy, heterogeneity, and textural fill volume. RESULTS: The physical properties and variation in hardness of ingested foods is reflected by significant differences in the microwear variables on buccal enamel surfaces between species, which is in agreement with early reports using 2D microwear signatures of the same samples. Species that consume hard brittle items showed high buccal enamel complexity and low anisotropy values, while folivorous species that consume tough foods revealed high anisotropy and low complexity enamel patterns. DISCUSSION: Buccal microwear texture analysis on enamel surfaces clearly reflects diet-related variation in nonhuman primates. Our findings indicate that microwear texture attributes on nonworking enamel surfaces provide an alternative procedure for reconstructing dietary behavior when wear facets on occlusal surfaces are lacking.