Association between cup fixation screw and iliopsoas impingement after total hip arthroplasty.

BACKGROUND: Iliopsoas impingement after total hip arthroplasty can result not only from acetabular cup but also from cup fixation screw. However, research addressing this screw impingement is scarce, leaving the details undetermined. This study aimed to elucidate the incidence and threshold of symptomatic iliopsoas impingement attributable to protrusion of the cup fixation screw into the iliopsoas muscle and to evaluate its impact on postoperative radiographic imaging findings and patient-reported outcome measures. METHODS: A total of 152 hips were included in this study. The symptomatic threshold of screw protrusion was determined using a receiver operating characteristic curve, and patients were divided into low-protrusion and high-protrusion groups using this threshold. The area and Hounsfield Unit values of the iliopsoas muscle on CT and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire postoperatively were investigated. FINDINGS: 10 hips (6.5%) were exhibited symptoms of IPI in this series. The threshold for screw protrusion length was identified as 6.4 mm. Patients in the high protrusion group exhibited significantly larger area and lower Hounsfield Unit values of the iliopsoas muscle. In addition, the high protrusion group revealed significantly lower scores (total, pain, movement, mental). Furthermore, subscales scores (pain, movement) in the high protrusion group didn't improve from 3 months to 12 months postoperatively with significance. INTERPRETATION: This study underscores the imperative for surgeons to consider the length of the cup fixation screw. This careful consideration is crucial for mitigating the incidence of postoperative iliopsoas impingement and enhancing total hip arthroplasty outcomes.

Evaluation of articular cartilage degeneration in patients with osteonecrosis of the femoral head using T2 mapping magnetic resonance imaging.

OBJECTIVES: To evaluate and characterise articular cartilage degeneration in patients with osteonecrosis of the femoral head (ONFH) using T2 mapping magnetic resonance imaging (MRI). METHODS: We reviewed 35 patients with ONFH (20 males and 15 females, mean age 45.7±12.9 years) without obvious cartilage abnormalities on plain MRI (ONFH group) and 25 healthy volunteers (9 males and 16 females, mean age 42.9±5.8 years) (control group). All patients underwent T2 mapping MRI after ONFH onset. The region of interest was defined as the weight-bearing portion of the articular cartilage in the femoral head and acetabulum in the coronal view. RESULTS: The T2 values of the articular cartilage of the acetabulum and femoral head, including necrotic and normal regions, were significantly higher in the ONFH group than those in the control group. These T2 values of the acetabulum and femoral head in stages 3A and 2 were significantly higher in the ONFH group than those in the control group. CONCLUSIONS: The articular cartilage of the acetabulum and femoral head can deteriorate after the onset of ONFH, which may affect the natural history of ONFH and ONFH treatment. Our findings suggest the need for early intervention in joint preservation surgery.

Evaluation of the long-term patient-reported outcomes after hip arthroplasty or joint preserving with Sugioka femoral osteotomy in patients with femoral head osteonecrosis.

PURPOSE: This study retrospectively evaluated long-term clinical outcomes and patient-reported outcome measures (PROMs) in patients with osteonecrosis of the femoral head (ONFH) who underwent transtrochanteric rotational osteotomy (TRO), curved varus osteotomy (CVO), and total hip arthroplasty (THA). METHODS: We retrospectively reviewed the 109 hips in 96 patients (46 men, 50 women) who underwent CVO, TRO, or THA for ONFH treatment. The mean follow-up period for the TRO, CVO, and THA groups was 14.8, 11.5, and 13.3 years, respectively. RESULTS: The THA conversion rate of the TRO patients was significantly higher than that of the patients with CVO, and the final clinical scores in the patients with TRO did not improve compared with preoperative scores. Postoperative PROMs showed that the total and pain scores of the patients with THA were significantly higher than those of patients with TRO and CVO, while the PROM score did not change between patients with TRO and CVO. The analysis further showed that the preoperative type C2, stage 3A, or postoperative type C1 and C2 were significant predictors of decreased final PROM scores. CONCLUSION: This study found that CVO and THA are clinically effective treatments for ONFH, with significant improvements compared with preoperative scores. However, THA was associated with significantly higher PROMs and pain scores than those of CVO and TRO in long-term follow-up. Furthermore, our results suggest that postoperative PROMs depend mainly on the preoperative level of collapse and postoperative transposed intact ratio of the articular surface of the femoral head.

Investigating the subchondral trabecular bone microstructure in patients with osteonecrosis of the femoral head using multi-detector row computed tomography.

OBJECTIVES: To analyse the microstructural changes of subchondral trabecular bone in patients with osteonecrosis of the femoral head (ONFH) using multi-detector row computed tomography (MDCT). METHODS: We retrospectively investigated 76 hips in 50 patients diagnosed with ONFH between 2017 and 2021. Groups 1, 2, 3, and 4 comprised hips without ONFH, ONFH without femoral head collapse (FHC), ONFH with mild collapse (<2 mm), and ONFH with severe collapse (>2 mm), respectively. All patients underwent MDCT, and the subchondral trabecular bone microstructure was assessed. Regions of interests were set at the lateral boundary of the femoral head necrotic lesion and centre of the acetabular weight-bearing portion. RESULTS: In both the femoral head and the acetabular regions, there were significant differences in Groups 2 and 3 compared to Group 1, with increased volumetric bone mineral density and apparent bone volume fraction, and more plate-like with increased connectivity, indicating that osteosclerotic changes were occurring. CONCLUSIONS: In both the femoral head and the acetabular regions, osteosclerotic changes of subchondral trabecular bone microstructure were present before FHC.

The impact of increasing femoral offset and stem anteversion on postoperative dislocation in bipolar hemiarthroplasty.

BACKGROUND: Femoral offset and anteversion have been reported to affect the incidence of dislocation following bipolar hemiarthroplasty, although the magnitudes of contributions of the femoral offset and stem anteversion on dislocation, both singly and in combination is not fully understood. METHODS: Using the CT data of 61 patients (61 hips), including 30 male and 31 female who underwent bipolar hemiarthroplasty, three-dimensional dynamic motion analysis was performed using a modular implant that enabled adjustment of femoral offset and stem anteversion independently. The pattern of impingement and relationship between femoral offset/stem anteversion and range of motion were evaluated using the software. FINDINGS: We found that a higher femoral offset and stem anteversion correlate with a greater range of motion of flexion and internal rotation. Furthermore, an increased femoral offset has a great effect on increasing range of motion of flexion than stem anteversion, and increased both femoral offset and stem anteversion have fewer effect on the flexion, whereas increasing stem anteversion has a great impact on internal rotation than offset, especially in the case with lower femoral anteversion. However, a higher stem anteversion decrease the range of motion of external rotation, whereas a higher femoral offset leads to an increased range of motion of external rotation. INTERPRETATION: We demonstrated that both a higher femoral offset and stem anteversion substantially affected the range of motion in flexion, internal rotation and external rotation. However, these are not independent, but rather mutually confounding, the surgeons should consider retaining femoral/anterior offset in bipolar hemiarthroplasty.

Associations between implant alignment or position and patient-reported outcomes after total hip arthroplasty.

BACKGROUND: We aimed to evaluate the associations between implant alignment/position and patient-reported outcomes following total hip arthroplasty using CT-based simulation software. METHODS: We reviewed hips of 137 patients (27 males, 110 females, mean age: 67.3 years old) who underwent total hip arthroplasty. Radiographic evaluations were based on the software for evaluation of the parameters related to implant alignment/position and femoral/3-dimensional offset using post-operative CT data. Pre-operative and one-year post-operative patient-reported outcomes using Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire scores were evaluated. FINDINGS: The total and movement scores of normal combined anteversion and stem anteversion angle groups were significantly higher than those of lower and higher groups. The pain and movement scores of decreased femoral offset group were significantly lower than those of restored and increased femoral offset group. There were no significant differences in all scores in cup inclination and anteversion angle, stem coronal alignment, and 3-dimensional femoral offset among groups. Moreover, investigation of the associations between combined anteversion angle/stem anteversion/femoral offset and movement scores revealed that combined anteversion angle and stem anteversion were significantly associated with the movement that needs deep hip flexion and occasionally deep abduction, and high femoral offset was also associated with the movement that needs deep hip flexion. INTERPRETATION: Surgeons should consider the stem anteversion, stem sagittal alignment, and combined anteversion, in addition to the femoral offset to achieve patient's post-operative satisfaction, although the surgeon may have a relatively larger choice for the implant positioning, especially on the cup side.