The Length of Diaphyseal Contact of Tapered Fluted Stems is Highly Dependent on Canal Morphology

Bone Quality Assessment Before Total Hip Arthroplasty: The Role of Densitometry

Background Total hip arthroplasty (THA) is effective in the treatment of hip osteoarthritis. Radiographic evaluation, standard in THA planning, is sufficient in examining hip anatomy, although it may not precisely assess bone quality. A routinely implemented method in bone quality assessment is densitometry. The technique allows for a measurement of bone mineral density (BMD). Methodology In the study, we included 26 participants who qualified for THA. All the patients were preoperatively examined with radiographs and densitometry of the affected hip. On the preoperative anteroposterior radiograph, we measured the canal-to-calcar isthmus ratio (CC ratio) and the cortical index (CI). Intraoperatively, during the THA procedure, we measured the thickness of the cortical bone and the diameter of the femoral neck in the line of neck resection. Results The examination with Pearson's correlation coefficient revealed that BMD significantly positively correlates with the intraoperatively measured diameter of the femoral neck (r = 0.5, P = 0.009), and with the measured thickness of the cortical bone (r = 0.47, P = 0.015), CI significantly positively correlates with the intraoperatively measured diameter of the femoral neck (r = 0.6, P = 0.001), and with the CC ratio (r = 0.44, P = 0.024), the intraoperatively measured diameter of the femoral neck significantly positively correlates with the intraoperatively measured thickness of the cortical bone (r = 0.59, P = 0.001). All of the other correlations were not statistically significant. Conclusions BMD measurements can be used in THA planning as they positively correlate with intraoperative measurements. The radiological parameters (CC ratio and CI) may not be as precise in bone quality assessment.

Bleeder's Femur: The Proximal Femoral Morphology in Hemophilic Patients Who Underwent Total Hip Arthroplasty

INTRODUCTION

Patients with hemophilia (PWH) constantly suffer hemarthrosis, which leads to deformity of the hip joint. Therefore, PWH who are going to receive total hip arthroplasty (THA) should be exclusively treated before the surgery with careful measurement of their proximal femur. Hence, we conducted a retrospective study to explore the anatomical parameters of and differences in the proximal femur in hemophilic patients who underwent THA.

METHODS

The retrospective study comprised data of adult patients who received total hip arthroplasty from 2020 to 2022 in the research center. Patients having a diagnosis of hemophilic arthritis and received THA were included in experimental group, and patients with hip arthritis or femoral head necrosis were taken as control group. Parameters including femoral offset, neck-shaft angle (NSA), medullary cavity of 20 mm above mid-lesser trochanter level (T+20), mid-lesser trochanter level (T), and 20 mm blow it (T-20), and canal flare index (CFI), femoral cortical index (FCI) were measured on X-ray and CT images with PACS by two independent doctors. Data was analyzed by SPSS 20. Kolmogorov-Smirnov test was used to test data normality. Student's t-test was performed between PWH and control group. p < 0.05 was considered statistically significant.

RESULTS

Among the 94 hips, 39 (41.5%) were included in group hemophilia and 55(58.5%) in control group. The mean age of the patients was 49.36 ± 12.92 years. All cases were male patients. Data demonstrated significantly smaller femoral cortical index (FCI), femoral offset, medullary cavity of 20 mm above mid-lesser trochanter level, mid-lesser trochanter level, and 20 mm below it, and neck-shaft angle (NSA) was obviously larger in PWH than control group (p < 0.05). No significant difference was found in canal flare index (CFI).

CONCLUSION

Hemophilic patients undergoing THA were prone to longer and thinner proximal femur. Preoperative morphological analysis of femur is recommended.

The Stability of Fixation of Vancouver B2 Periprosthetic Femoral Fractures: Effect of Implantation Technique

INTRODUCTION

Due to increasing volume of total hip arthroplasties, periprosthetic femoral fractures have become a common complication with increased revision burden and perioperative morbidity. The objective of this study was to evaluate the fixation stability of Vancouver B2 fractures treated with two techniques.

METHODS

A common B2 fracture was created by reviewing 30 type B2 cases. The fracture was then reproduced in 7 pairs of cadaveric femora. The specimens were divided into two groups. In Group I ("reduce-first"), the fragments were reduced first, followed by implantation of a tapered fluted stem. In Group II ("ream-first"), the stem was implanted in the distal femur first, followed by fragment reduction and fixation. Each specimen was loaded in a multi-axial testing frame with 70% of peak load during walking. A motion analysis system was used to track the motion of the stem and fragments.

RESULTS

The average stem diameter in Group II was 16.1±0.4 millimeters (mm), versus 15.4 ±0.5mm in Group I. The fixation stability was not significantly different in the two groups. After the testing, the average stem subsidence was 0.36±0.31mm and 0.19±0.14mm (P=0.17), and the average rotation was 1.67±1.30° and 0.91±1.11° (P=0.16) in Group I and II, respectively. Compared to the stem, there was less motion of the fragments, and there was no difference between the two groups (P>0.05).

CONCLUSIONS

When tapered fluted stems were used in combination with cerclage cables for treatment of type B2 periprosthetic femoral fractures, both the "reduce-first" and "ream-first" technique showed adequate stem and fracture stability.