The association of postoperative global femoral offset with total hip arthroplasty outcomes

Risk factors for residual pelvic obliquity one year after total hip arthroplasty

PURPOSE

It is not uncommon for patients with hip disorders to present with pelvic obliquity (PO), and residual PO after total hip arthroplasty (THA) may not only affect hip joint function but also cause adjacent intervertebral joint disorders. This study aimed to investigate the postoperative PO impact on clinical outcomes and risk factors by comparing patients who had PO after THA to those who did not.

METHODS

A single-center, retrospective cohort study was conducted. A total of 103 patients who underwent THA were included in this study from 2018 to 2020. Demographics, functional outcomes, and spinopelvic parameters were compared between post-THA PO of less than 2° (NT group, 55 patients) and PO of 2° or more (O group, 48 patients). Multivariate analysis was performed using factors with significant differences in univariate analysis.

RESULTS

Postoperative Harris Hip Score Activity was significantly lower in the T group than in the NT group (p = 0.031). Preoperative PO was smaller in the NT group than in the T group (p = 0.001). Preoperative lumbar bending range (LBR) was significantly more flexible in the NT group than in the T group. In the logistic regression analysis, Age (odds ratio 0.957, 95% CI 0.923-0.993, p = 0.020), preoperative PO (odds ratio 1.490, 95% CI 1.100-2.020, p = 0.001), and LBR (odds ratio 0.848, 95% CI 0.756-0.951, p = 0.005) were found to be significant factors.

CONCLUSION

Younger age and large preoperative PO, and poor lumbar spine mobility were identified as risk factors for residual postoperative PO.

Impact of Offset and Leg Length on Functional Outcomes Post-Total Hip Arthroplasty: How Accurate Should Coronal Reconstruction Be?

BACKGROUND

Accurate hip reconstruction is associated with improved biomechanical behavior following total hip arthroplasty (THA). However, whether this is associated with improved patient-reported outcomes (PROs) is unknown.

HYPOTHESIS/PURPOSE

This study aimed to: 1) describe the ability to reconstruct coronal geometry during THA without advanced technology; 2) assess whether restoration of global offset (GO) and leg length (LL) is associated with improved PROs; and 3) investigate whether increased femoral offset (FO) to compensate for reduced acetabular offset (AO) influences PROs.

METHOD

This was a prospective, multicenter, consecutive cohort study of 500 patients treated with primary THA without robotics or navigation. The Oxford Hip score (OHS) was obtained preoperatively and at 1-year follow-up. Supine anteroposterior pelvic radiographs were analyzed to determine AO, FO, GO, and LL relative to the native contralateral side. Contour plots for ΔOHS based on ΔLL and ΔGO were created, and ΔOHS was calculated within and outside various ranges (±2.5, ±5, or ±10 mm).

RESULTS

In the operated hip, mean FO increased by 3 ± 6 mm (range, -16 to 27), while AO decreased by 2 ± 4 mm (range, -17 to 10). The contour graph for ±2.5 mm zones showed the best outcomes (ΔOHS >25) with GO and LL centered on 0 ± 2.5 mm (P < .01). However, only 10% achieved such reconstruction. When GO and LL differences were within ±10 mm, ΔOHS was superior when both AO and FO were within ±5 mm (mean: 24 ± 10; range, -5 to 40) compared with when FO was above 5 mm to compensate for a reduction in AO (mean: 22 ± 11; range, -10 to 46; P = .040).

CONCLUSIONS

The PROs were associated with biomechanical reconstruction, and the best clinical improvement can be expected when GO and LL differences are both within 2.5 mm. Maintenance of AO is important, as compensation by increasing FO is associated with inferior OHS.

A new seven-axis robotic-assisted total hip arthroplasty system improves component positioning: a prospective, randomized, multicenter study

This study compared the radiologic and clinical outcomes of a new seven-axis robotic-assisted total hip arthroplasty (THA) and conventional THA. Hundred and four patients were randomly assigned to two groups-the robotic-assisted THA group (RAS group) and the conventional THA group (CON group). The preoperative and postoperative Harris Hip score (HHS), acetabular inclination, anteversion, femoral offset, and leg length discrepancy (LLD) were compared. During the follow-up, no patients had any complications that could be associated with the use of the robot. The proportion of acetabular cups in the safety zone was significantly higher in the RAS group than that in the CON group. The two groups had significantly different mean absolute difference of inclination and anteversion. There was no significant difference in the postoperative HHSs, changes in HHSs, femoral offset, and lower limb length between the two groups. The seven-axis robotic-assisted THA system is safe and effective, and leads to better acetabulum cup positioning compared to conventional THA. The improvements observed in the HHS, LLD, and femoral offset in the RAS group were similar to those in the CON group.Clinical trial registration time: 19/05/2022.Clinical trial registration number: ChiCTR2200060115.

The effect of intraoperative fluoroscopy on acetabular component positioning and patient anatomy restoration during posterior or posterolateral approach total hip arthroplasty: a meta-analysis

BACKGROUND

Positioning implant components and restoring patient anatomy during total hip arthroplasty (THA) are essential for joint stability, polyethylene liner wear, and range of motion. Previous studies comparing intraoperative fluoroscopy with no fluoroscopy during the posterior or posterolateral approach have reported conflicting results. This meta-analysis evaluated if intraoperative fluoroscopy improves component positioning and femoral component position compared to no fluoroscopy during posterior or posterolateral approach total hip arthroplasty.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed when conducting the systematic review. We searched Web of Science, Embase, PubMed, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CBM, CNKI, VIP, and Wanfang database in May 2023 to identify studies involving Intraoperative fluoroscopy versus no fluoroscopy during posterior or posterolateral approach total hip arthroplasty. Finally, we identified 1133 patients (1145 hips) assessed in seven studies.

RESULTS

There were no significant differences in terms of acetabular cup inclination angle (ACIA, P = 0.43), ACIA within safe zone rate (P = 0.58), acetabular cup anteversion angle (ACAA, P = 0.46); ACAA within safe zone rate (P = 0.72), Combined safe zone rate (P = 0.28), dislocation rate (P = 0.64) and infection rate (P = 0.94) between two groups. Compared with the no fluoroscopy group, the intraoperative fluoroscopy group had more operation time (P < 0.00001), less femoral component offset difference (FCOD, P = 0.03), and less LLD (P < 0.00001).

CONCLUSION

Even though intraoperative fluoroscopy was not related to an improvement in cup location or dislocation incidence. Our findings demonstrate that the restoration of leg lengths and femoral offset can be significantly improved by using intraoperative fluoroscopy to supplement good surgical skills in THA. The advantages of intraoperative fluoroscopy might become more apparent for surgeons with less experience. To ascertain whether intraoperative fluoroscopy for posterior or posterolateral approach total hip arthroplasty will have clinical benefits and improve the survival of prostheses, more well-powered and well-designed long-term follow-up studies were necessary.

Coordinate value of the femoral head center estimated using those of the tip of the greater trochanter and lesser trochanter

Several studies have reported estimating the femoral head center (FC) from reference points on the pelvis; however, none have reported estimates obtained from those on the femur. In this cross-sectional study, we investigated the estimated point of FC from the coordinate value of the tip of the greater trochanter (GT) and lesser trochanter (LT) using a formula with a three-dimensional measurement technique. We used data from 92 healthy Japanese subjects without any back or knee symptoms and no abnormalities in the hip, knee, or spine on plain radiographs. In our study, the difference in the anteroposterior direction was larger than that in the other directions. We speculate that the accuracy of defining the tip of the LT is difficult in the anteroposterior direction. Moreover, the correlation coefficients were larger for women. The reason for this was unclear because the variation in the proximal femur may be similar in women. We found that the average difference between the actual and calculated values was approximately 2 mm. We considered that the coordinate value of the FC from the tip of the GT could be estimated more accurately using the regression equation compared to previous methods based on pelvic reference points.