Search

Introduction: The aim of this study was to analyse the relationship between bony joint orientation and the distribution of hip musculature. Methods: The bone anatomy of the hip (femoral antetorsion (AT), acetabular anteversion (AV), and combined anteversion (AV/AT)) and the muscle volume of the gluteal muscles and the tensor fasciae latae were analysed bilaterally using computed tomography data of 49 patients. Muscle force direction (MFD) was determined for each muscle. The total MFD of the hip musculature was calculated and then correlated with the bony anatomy. Results: The mean AV, AT, and AV/AT were 21.9° ± 5.9°, 7.22° ± 7.4°, and 29.2° ± 9°, respectively. We found the following mean muscle volumes: gluteus maximus: 780 ± 227 cm3, gluteus medius: 322 ± 82 cm3, gluteus minimus: 85 ± 20 cm3, and tensor fasciae latae: 68 ± 22 cm3. The mean MFD was 18.92° ± 1.29°. We found a uniform distribution of the musculature that was not correlated with the bone anatomy. Conclusion: This study highlights the variability in native acetabular and femoral anatomy and that bone hip anatomy does not correlate with the distribution of hip musculature. Although native acetabular anteversion matches the suggested targets for cup insertion, native combined anteversion is not related to current implant insertion targets. Understanding native muscular anatomy and the alterations that occur with different surgical approaches can serve as an explanatory model for THAs that has become unstable despite the components being implanted within the safe zone. [ABSTRACT FROM AUTHOR]

Purpose: Clinical reports on meniscal scaffolds seem promising, albeit relatively paucity exists regarding their biomechanical behavior. The aim of the study is to delineate the impact of differing suture materials and the type as well as the temperature of the irrigation fluid on the pull-out strength of a polyurethane meniscal scaffold (Actifit®).Materials and Methods: 128 specimens were utilized with horizontal sutures and uniaxial load-to-failure testing was performed. We compared two different suture materials-polydioxanone (PDS) and non-absorbable, braided polyester sutures (NABP)-as well as two common irrigation fluids-lactated Ringer's and electrolyte-free, hypotonic Mannitol-Sorbitol. All specimens were further evaluated according to two different temperatures [room temperature (20 °C) and near-core body temperature (37 °C)].Results: Mean load-to-failure was 53.3 ± 6.5 N. There was no significant difference between the NABP and the PDS group. Ringer group showed a significantly higher load-to-failure compared to Purisole (P = .0002). This was equivalent for both PDS (P = .0008) and NABP sutures (P = .0008). Significantly higher failure loads could be established for the 37° group (P = .041); yet, this difference was neither confirmed for the PDS or in in the NABP subgroup. Only the subgroup using Purisole at 37° showed significantly higher failure loads compared to 20° (P = .017).Conclusions: This study underlines the potential to improve pull-out strength during implantation of an Actifit® scaffold by alteration of the type of irrigation fluid. Lactated Ringer solution provided the highest construct stability in regard to load-to-failure testing and should be considered whenever implantation of a polyurethane meniscal scaffold is conducted. [ABSTRACT FROM AUTHOR]

Background: Displaced femoral neck fractures frequently are treated with bipolar hemiarthroplasties. Despite the frequency with which bipolar hemiarthroplasty is used to treat these fractures, there are few long-term data.Questions/purposes: We sought to evaluate (1) the cumulative incidence of revision for any reason of bipolar hemiarthroplasties at 20 years, and the proportion of patients who lived more than 20 years who still have the prosthesis in situ from the index arthroplasty, (2) the cumulative incidence of aseptic loosening at 20 years, and (3) the Harris hip score of the surviving patients at long term.Methods: We performed 376 cemented bipolar hemiarthroplasties for displaced femoral neck fractures in 359 patients between 1976 and 1985. At a minimum of followup of 20 years (mean, 24 years; range, 20-31 years), 339 of 359 patients (94%) were deceased, leaving 20 patients in the study group. Of those, one patient was confirmed to be lost to followup and two others had radiographic followup only. Three hundred fifty-nine patients (99.2%) (376 of the original 379 hips) were followed until death, revision of the hemiarthroplasty, or for at least 20 years (of clinical followup). Bipolar hemiarthroplasty was performed for displaced femoral neck fractures. Cemented fixation was the standard of care between 1976 and 1985 at our institution. The mean age of the patients at the time of surgery was 79 years (range, 60-99 years). The cumulative incidence of revision, estimated with death as a competing risk, and radiographs were evaluated for signs of aseptic loosening by a surgeon not involved in the clinical care of the patients. Clinical function was evaluated with the Harris hip score. The mean age of the patients at the time of surgery was 79 years.Results: The 20-year cumulative incidence of revision for any reason was 3.5% (95% CI, 1.6%-5.3%). Of the 20 patients who survived more than 20 years, seven had the implant intact. The 20-year cumulative incidence of revision for aseptic loosening was 1.4% (95% CI, 0.2%-2.6%). The mean Harris hip score in patients who were still living and patient who did not have revision surgery was 63 ± 22, however 13 of the 20 patients had undergone revision surgery.Conclusions: The long-term survivorship of bipolar hemiarthroplasty prostheses used to treat displaced femoral neck fractures in the elderly was high, and the procedure can be considered definitive for the majority of elderly patients with a femoral neck fracture. In this series, 6% (20 patients, 339 of 359) of the patients survived more than 20 years after treatment of a femoral neck fracture with a bipolar hemiarthroplasty. Of those, 35% (seven of 20) survived with their index prosthesis in situ.Level Of Evidence: Level IV, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Standing long-leg radiographs allow assessment of the mechanical axis in the frontal plane before and after total knee arthroplasty (TKA). An alteration in loading, and hence in the forces acting on the knee joint, occurs postoperatively. We therefore postulated that the mechanical axis measured in the long-leg standing radiograph would change within the first year after TKA.Methods: Standing long-leg radiographs of 156 patients were performed 7 days, 3 months, and 12 months after TKA with determination of mechanical axis of the lower limb.Results: Seven days after surgery, the mechanical axis amounted 0.8° ± 1.7° valgus. Three months after the operation, at 1.3° ± 1.3° varus, it was significantly different (P < .001) from the primary measurement. No further alteration in the mechanical axis occurred during the first year after TKA. This difference was even more pronounced (P < .001) in patients with a postoperative lack of complete extension. Seven days after surgery, they had a valgus axis deviation of 1.6° ± 1.6°; after 3 months, the measurement amounted 1.2° ± 1.3° varus.Conclusion: Measured by a standing long-leg radiograph, the frontal mechanical axis after TKA changes over time. The predictive power of a standing long-leg radiograph in the first week after surgery is limited because limb loading is altered because of pain and is therefore nonphysiological. The actual mechanical axis resulting after TKA can only be assessed in a standing long-leg radiograph at physiological loading. [ABSTRACT FROM AUTHOR]