The influence of surgical approach on postoperative pelvic tilt after total hip arthroplasty

Changes of spino-pelvic characteristics post-THA are independent of surgical approach: a prospective study

AIMS

Spinopelvic characteristics change after THA. Whether this change varies between approaches, is of interest for pre-op cup orientation planning. The aims of this study were to (1) Characterize changes in standing PT amongst patients with hip osteoarthritis treated with THA; (2) Test whether certain patient-related factors may predict PT change; and (3) Assess the association between surgical approach and PT change.

METHODS

This was a prospective, two-center, radiographic outcome study including 424 hips, consisting of anterior approach for 171 (40.3%) hips, lateral approach for 181 hips (42.7%) and posterior approach for 72 hips (17.0%). Spinopelvic characteristics were determined from lateral radiographs (before and one year after THA). Parameters of interest included: Pelvic tilt (PT), lumbar lordosis, sacral slope, pelvic incidence. PT change of more than 7 ° was considered clinically relevant.

RESULTS

Pelvic tilt increased by 2 ° from 15.1 ° (± 8.9) to 17.1 ° (± 9.7) after THA (p < 0.001). 19 hips (4.5%) experienced a relevant PT decrease, 337 (79.5%) had no clinically significant change in pelvic tilt, and 68 (16.0%) showed a moderate increase. Age, female sex and preoperative spinopelvic parameters including PT, SS and PI were predictive of PT change more than 7 °. PT increased most with lateral approach (2.9 ± 6.2) and least with anterior approach (1.1 ± 6.2, p = 0.024).

CONCLUSION

Preoperative PT is the best predictor for PT change. PT is generally normalizing after THA and patients with low PT due to hip flexion contractures tend to increase PT after THA, few patients with high PT will decrease after THA. Anterior approach with capsulectomy was associated with the least change in PT post-THA. However, the approach-specific changes, although statistically significant, were too small to be considered during clinical practice, therefore no approach-specific prediction of PT change needs to be considered during preoperative planning for primary THA.

Challenges in Total Hip Arthroplasty with Prior Spinal Arthrodesis: A Comprehensive Review of Biomechanics, Complications, and Surgical Strategies

Total hip arthroplasty (THA) has revolutionized patients' lives with hip osteoarthritis. However, the increasing prevalence of THA in individuals with prior lumbar arthrodesis (LA) poses unique challenges. This review delves into the biomechanical alterations, complications, and surgical strategies specific to this patient subset, highlighting the need for tailored preoperative assessments and planning. Due to altered pelvic and spinal biomechanics, patients with LA undergoing THA face a higher risk of dislocation and revision. The complex interplay between spinal and hip biomechanics underscores the need for meticulous preoperative planning. Comprehensive clinical examination and radiographic evaluation are vital for understanding patient-specific challenges. Various radiographic techniques, including computed tomography (CT)/X-ray matching and standing/seated studies, provide insights into postural changes affecting pelvic and spinal alignment. Complications following THA in patients with LA highlight the necessity for personalized surgical strategies. Careful consideration of implant selection, the surgical approach, and component positioning are essential to prevent complications. In summary, THA in patients with prior LA demands individualized preoperative assessments and planning. This approach is crucial to optimize outcomes and mitigate the heightened risks of complications, underlining the importance of tailored surgical strategies.

Excessive posterior pelvic tilt from preoperative supine to postoperative standing after total hip arthroplasty

Aims

Excessive posterior pelvic tilt (PT) may increase the risk of anterior instability after total hip arthroplasty (THA). The aim of this study was to investigate the changes in PT occurring from the preoperative supine to postoperative standing position following THA, and identify factors associated with significant changes in PT.

Methods

Supine PT was measured on preoperative CT scans and standing PT was measured on preoperative and one-year postoperative standing lateral radiographs in 933 patients who underwent primary THA. Negative values indicate posterior PT. Patients with > 13° of posterior PT from preoperative supine to postoperative standing (ΔPT ≤ -13°) radiographs, which corresponds to approximately a 10° increase in functional anteversion of the acetabular component, were compared with patients with less change (ΔPT > -13°). Logistic regression analysis was used to assess preoperative demographic and spinopelvic parameters predictive of PT changes of ≤ -13°. The area under receiver operating characteristic curve (AUC) determined the diagnostic accuracy of the predictive factors.

Results

PT changed from a mean of 3.8° (SD 6.0°)) preoperatively to -3.5° (SD 6.9°) postoperatively, a mean change of -7.4 (SD 4.5°; p < 0.001). A total of 95 patients (10.2%) had ≤ -13° change in PT from preoperative supine to postoperative standing. The strongest predictive preoperative factors of large changes in PT (≤ -13°) from preoperative supine to postoperative standing were a large posterior change in PT from supine to standing, increased supine PT, and decreased standing PT (p < 0.001). Flexed-seated PT (p = 0.006) and female sex (p = 0.045) were weaker significant predictive factors. When including all predictive factors, the accuracy of the AUC prediction was 84.9%, with 83.5% sensitivity and 71.2% specificity.

Conclusion

A total of 10% of patients had > 13° of posterior PT postoperatively compared with their supine pelvic position, resulting in an increased functional anteversion of > 10°. The strongest predictive factors of changes in postoperative PT were the preoperative supine-to-standing differences, the anterior supine PT, and the posterior standing PT. Surgeons who introduce the acetabular component with the patient supine using an anterior approach should be aware of the potentially large increase in functional anteversion occurring in these patients.

Post-THA gait training to improve pelvic obliquity and decrease leg length discrepancy in DDH patients: a retrospective study

Objectives

To investigate the value of a post-operative gait training program to improve pelvic obliquity (PO) and decrease leg length discrepancy (LLD) for patients with Crowe type I developmental dysplasia of the hip (DDH) undergoing unilateral total hip arthroplasty (THA).

Methods

The prospective group consisted of 35 patients who underwent one-stage unilateral THA. Pre- and post-training PO and LLD were measured for the radiological assessment and Harris Hip Score (HHS) was used for the functional assessment.

Results

The HHS improved from 55.54 ± 10.61 pre-operatively to 84.97 ± 7.63 after surgery. The mean post-training PO angle for grade 0, grade 1, and grade 2 were 2.66 ± 1.42, 2.94 ± 1.42, and 5.60 ± 1.90, respectively, compared with pre-training values of 1.42 ± 0.58, 4.17 ± 0.90, and 6.96 ± 0.46. The mean post-training LLD for grade 0, grade 1, and grade 2 were 0.83 ± 0.91, 0.56 ± 0.48, and 0.36 ± 0.30, respectively, compared with pre-training values of 0.70 ± 0.23, 1.25 ± 0.90, and 1.46 ± 1.60.

Conclusion

Gait training following unilateral THA can improve PO and decrease functional LLD in grade I DDH patients. This method may have moderate success for grade 0 DDH patients and provide limited benefit for grade II patients. Appropriate release of the soft tissues may be required for grade II DDH patients to obtain a better walking gait.

Effect of pelvic tilt and rotation on cup orientation in standing anteroposterior radiographs

BACKGROUND

Individual pelvic tilt and rotation have wide variability that can affect the measurement of cup orientation in anteroposterior (AP) radiographs. The purpose of this study was to analyse the effect of pelvic tilt and rotation on radiographic measurements of cup orientation.

METHODS

A total of 53 patients (63 hips) were included in this study. The patients underwent a computed tomography study with standing AP pelvis radiographs taken both preoperatively and approximately 3 months postoperatively. We used 2-dimensional/3-dimensional matching to measure the pelvic tilt and rotation, and the non-standardised and standardised cup orientation.

RESULTS

There was no difference in the pelvic tilt and rotation between the preoperative and postoperative radiographs. The distribution of the differences between the non-standardised and standardised cup anteversion exhibited a change within 5° in only 34/63 (54%) hips. The pelvic tilt correlated with the difference between the non-standardised and standardised cup anteversion, but the pelvic rotation did not. When all 63 hips were separated into the right and left sides, the pelvic rotation inversely correlated with the pelvic tilt-adjusted difference between the non-standardised and standardised cup anteversion of the right side but directly correlated with that of the left side.

CONCLUSIONS

The current study demonstrated that the measurement of cup anteversion in standing AP radiographs is significantly affected by both the pelvic tilt and pelvic rotation. An improved understanding of the pelvic orientation may eventually allow for desired cup positioning on a patient-specific basis to potentially reduce complications associated with the malposition of the cup.