Patient Obesity Influences Pelvic Lift During Cup Insertion in Total Hip Arthroplasty Through a Lateral Transgluteal Approach in Supine Position

Robotic arm-assisted total hip arthroplasty via a minimally invasive anterolateral approach in the supine position improves the precision of cup placement in patients with developmental dysplasia of the hip

BACKGROUND

This study evaluated the accuracy of the cup alignment angles and spatial cup positioning on computed tomography (CT) images in patients with osteoarthritis secondary to developmental dysplasia of the hip (DDH) who underwent total hip arthroplasty (THA) using a minimally invasive technique via an anterolateral approach in the supine position according to whether a robotic arm-assisted system or a CT-based navigation system was used.

METHODS

We reviewed 60 robotic arm-assisted (RA)-THA cases and 174 navigation-assisted (NA)-THA cases. After propensity score matching, there were 52 hips in each group. Postoperative cup alignment angles and position were assessed by superimposition of a three-dimensional cup template onto the actual implanted cup using postoperative CT images with pelvic coordinates matching the preoperative planning.

RESULTS

The mean absolute error of the inclination angle and the anteversion angle between the preoperative planning and the postoperative measurement was significantly smaller in the RA-THA group (inclination, 1.1° ± 0.9; anteversion, 1.3° ± 1.0) than in the NA-THA group (inclination, 2.2° ± 1.5; anteversion, 3.3° ± 2.5). For acetabular cup positioning, the mean discrepancy between the preoperative planning and the postoperative measurement was 1.3 ± 1.3 mm on the transverse axis, 2.0 ± 2.0 mm on the longitudinal axis, and 1.3 ± 1.7 mm on the sagittal axis in the RA-THA group and 1.6 ± 1.4 mm, 2.6 ± 2.3 mm, and 1.8 ± 1.3 mm, respectively, in the NA-THA group. High precision of cup positioning was observed in both groups with no statistically significant difference.

CONCLUSION

Robotic arm-assisted THA using a minimally invasive technique via an anterolateral approach in the supine position allows accurate cup placement in patients with DDH.

Intraoperative Pelvic Tilt and Axial Rotation During Total Hip Arthroplasty Through the Direct Anterior Approach is Affected by the Acetabular Retractor and Cup Impactor

Background

Intraoperative pelvic motion during total hip arthroplasty (THA) in the supine position affects acetabular cup placement and occurs at each step of THA; however, there are no reports of pelvic motion changes during each stage of THA via the direct anterior approach (DAA). This study aimed to evaluate pelvic motion at each step of THA through the DAA.

Methods

From March to October 2022, 71 hips were prospectively measured for intraoperative pelvic tilt and axial rotation during THA through the DAA at a single center. These parameters were measured during each surgical step using the augmented reality-hip navigation system.

Results

Both pelvic tilt and axial rotation were maximal during acetabular cup placement. The mean intraoperative pelvic tilt and axial rotation during cup placement were 4.8 ± 2.6° (95% confidence interval, 4.19-5.41°) and 4.2 ± 3.3° (95% confidence interval, 3.42-4.98°), respectively. The effects of the acetabular retractor and cup impactor on pelvic tilt and axial rotation were comparable. Spearman's correlation tests showed significant correlation between axial rotation and body mass index (r = -0.444, P = .00011).

Conclusions

The pelvis tilts forward and rotates toward the surgical side during THA through the DAA. The effects of the acetabular retractor and cup impactor on pelvic motion are comparable. Cup implantation must take into account pelvic movement, and it must be recognized that the pelvis is moving at that time, even with only the acetabular retractor inserted, compared to before the skin incision.

Influence of obesity and intra-operative imaging guidance technology on acetabular cup positioning in total hip arthroplasty

BACKGROUND

Accuracy of acetabular cup positioning during total hip arthroplasty (THA) can be improved with intra-operative imaging but may be influenced by body mass index (BMI). This study assessed the influence of BMI (kg/m2) on cup accuracy when using intra-operative fluoroscopy (IF) alone or supplemented with a commercial product.

METHODS

This retrospective review included four consecutive cohorts of patients having undergone anterior approach THA with IF alone (2011-2015), IF and Overlay (2015-2016) (Radlink Inc., Los Angeles, CA), IF and Grid (2017-2018) (HipGrid Drone™, OrthoGrid Systems Inc., Salt Lake City, UT) and IF and Digital (2018-2020) (OrthoGrid Phantom®, OrthoGrid Systems, Inc., Salt Lake City, UT). Component placement accuracy was measured on 6-week post-operative weight bearing radiographs and compared between four BMI patient groups (BMI ≤ 25, 25 < BMI ≤ 30, 30 < BMI ≤ 35, and 35 < BMI). Total fluoroscopy times were also recorded directly from the fluoroscopy unit.

RESULTS

Abduction angle significantly increased as BMI increased (p = 0.003) with IF alone but no difference was present in groups with guidance technology. Anteversion was significantly different between BMI groups for IF alone (p = 0.028) and Grid (p = 0.027) but was not different in Overlay (p = 0.107) or Digital (p = 0.210). Fluoroscopy time was significantly different between BMI categories for IF alone (p = 0.005) and Grid (p = 0.018) but was not different in Overlay (p = 0.444) or Digital (p = 0.170).

CONCLUSION

Morbid obesity (BMI > 35) increases risk for malpositioning of acetabular cups and increases surgical time with IF alone or the Grid. Additional IF guidance technology (Overlay or Digital) increased cup positioning accuracy without decreasing surgical efficiency.

Accuracy of acetabular component alignment with surgical guidance systems during hip arthroplasty

BACKGROUND

Navigation in total hip arthroplasty has been shown to improve acetabular positioning and can decrease the incidence of mal-positioned acetabular components. This study aimed to assess two surgical guidance systems by comparing intra-operative measurements of acetabular component inclination and anteversion with a post-operative CT scan.

METHODS

We prospectively collected intra-operative navigation data from 102 hips receiving conventional THA or hip resurfacing arthroplasty through either a direct anterior or posterior approach. Two guidance systems were used simultaneously: an inertial navigation system (INS) and an optical navigation system (ONS). Acetabular component anteversion and inclination were measured on a post-operative CT.

RESULTS

The average age of the patients was 64 years (range: 24-92) and the average BMI was 27 kg/m² (range 19-38). 52% had hip surgery through an anterior approach. 98% of the INS measurements and 88% of the ONS measurements were within 10° of the CT measurements. The mean (and standard deviation) of the absolute difference between the postoperative CT and the intra-operative measurements for inclination and anteversion were 3.0° (2.8) and 4.5° (3.2) respectively for the ONS, along with 2.1° (2.3) and 2.4° (2.1) respectively for the INS. There was a significantly lower mean absolute difference to CT for the INS when compared to ONS in both anteversions (p < 0.001) and inclination (p = 0.02).

CONCLUSIONS

We found that both inertial and optical navigation systems allowed for adequate acetabular positioning as measured on postoperative CT, and thus provide reliable intraoperative feedback for optimal acetabular component placement.

LEVEL OF EVIDENCE

Therapeutic Level II.

Comparison of accuracy of cup position using portable navigation versus alignment guide in total hip arthroplasty in supine position

BACKGROUND

Accelerometer-based portable navigation systems in supine total hip arthroplasty (THA) have been developed, but there are no reports on the accuracy of cup placement. We aimed to investigate and compare the accuracy of the accelerometer-based portable navigation system versus the acetabular alignment guide placed on the pelvis in THA using the direct anterior approach (DAA). Both devices tracked changes in the pelvic position.

METHODS

In this single-centre, retrospective study, we reviewed 115 hips in 113 patients who underwent primary THA via the DAA using an accelerometer-based portable navigation system in the supine position (portable navigation group) and 106 hips in 101 patients who underwent THA using an acetabular alignment guide (alignment guide group) as controls. Hips were evaluated postoperatively using computed tomography to measure cup orientation. The accuracy of cup orientation was compared between the 2 groups.

RESULTS

Absolute values of inclination error were 3.1° ± 2.2° and 2.9° ± 2.3° (p = 0.708) in the portable navigation and alignment guide groups and those of anteversion error were 2.8° ± 2.3° and 3.7° ± 2.7°, respectively (p = 0.005). The number of cups placed within 10° of error was 98.3% and 96.2% in the portable navigation and alignment guide groups, respectively (p = 0.304). The portable navigation group had significantly more hips (72.2%) placed within a 5° margin of error than did the alignment guide group (56.6%) (p = 0.016).

CONCLUSION

High accuracy in cup placement was achieved using accelerometer-based portable navigation in supine THA. Using a navigation system may contribute to improved long-term outcomes.

Effects of body mass index and range of motion on intraoperative change in pelvic tilt during total hip arthroplasty using the direct anterior approach

BACKGROUND

Intraoperative pelvic tilt changes that occurs during total hip arthroplasty (THA) in the supine position affects cup placement and sometimes causes malalignment. The relationship between body mass index (BMI) and pelvic movement has been reported for some procedures, but not the direct anterior approach (DAA). The purpose of this study was to investigate intraoperative pelvic tilt changes that occurs during DAA.

METHODS

In this single-center, retrospective study, we reviewed 200 hips that underwent primary THA via DAA in the supine position using an accelerometer-based navigation system. Intraoperative changes in pelvic tilt and axial rotation from the start of surgery to cup placement were assessed using the navigation system. Preoperative clinical factors that increased pelvic tilt and axial rotation toward the surgical side by > 10° were analyzed via univariate and multiple logistic regression analyses.

RESULTS

The mean pelvic tilt value increased by 7.6° ± 3.8° (95% confidence interval [CI], 7.1-8.2; range, - 5.0-19.0) intraoperatively, and the axial rotation increased by 3.2° ± 2.7° (95% CI, 2.7-3.7; range, - 13.0-12.0). Univariate analysis revealed that the group with increased pelvic tilt showed significantly greater range of abduction and internal rotation, and significantly lower BMI than the group with no increased tilt. Pre-incisional pelvic tilt was significantly greater in the group with increased axial rotation than in the group with no increased rotation. On logistic regression analysis, BMI (odds ratio [OR], 0.889; 95% CI, 0.809-0.977; p = 0.014) and the range of internal rotation (OR, 1.310; 95% CI, 1.002-1.061; p = 0.038) were predictors of large increases in pelvic tilt. No predictors of large increases in axial rotation were identified.

CONCLUSION

Significant forward pelvic tilt was observed in patients with a low BMI values and high ranges of internal rotation via THA using the DAA. Findings indicated that surgeons should pay attention to intraoperative pelvic movements, which may help identify patients with significant pelvic tilt changes.

Early Surgical Complications of Total Hip Arthroplasty in Patients With Morbid Obesity: Propensity-Matched Cohort Study of 3683 Patients

BACKGROUND

The aim of this study is to determine whether the high risk of surgical complications within 1 year of total hip arthroplasty (THA) is due to associated comorbidities or morbid obesity alone as measured by body mass index (BMI ≥ 40 kg/m²).

METHODS

Population-based retrospective cohort study was conducted of all adults in Ontario undergoing primary THA for osteoarthritis (2012-2018). All patients were followed for 1 year. Outcomes were compared among matched groups (hypertension, diabetes, chronic obstructive pulmonary disease, frailty, congestive heart failure, coronary artery disease, asthma, and Charlson score). Primary outcome measure was major surgical complications within 1 year (composite of deep infection requiring surgery, dislocation requiring closed or open reduction, and revision surgery).

RESULTS

A total of 3683 patients with morbid obesity were matched and had a significantly greater risk of major complications within 1-year (132 [3.6%] vs 54 [1.5%]; hazard ratio [HR] 2.54, 95% confidence interval [CI]; 1.98-3.25). This included greater risk for deep infection requiring surgery (100 [2.8%] vs 26 [0.7%]; HR 3.85, 95% CI; 2.70-45.48) and revision arthroplasty (86 [2.4%] vs 34 [0.9%]; HR 2.61, 95% CI; 1.92-3.55). Operative time was also longer with a median 116 (99-138) vs 102 (87-121) minutes. There were no significant differences in hospital stay, cost of acute care episode, or medical complications.

CONCLUSION

Patients' large body habitus seems to contribute to the increased risk of surgical complications within 1-year of THA. Future research is needed to identify ways of mitigating surgical complications such as centralizing care for this complex group of patients in specialist centers.

Intraoperative pelvic movement is associated with the body mass index in patients undergoing total hip arthroplasty in the supine position

BACKGROUNDS

There are very few reports on pelvic movement during total hip arthroplasty (THA) in the supine position. We investigated intraoperative pelvic motion in the sagittal and axial planes to determine if preoperative clinical factors, including body mass index (BMI) affect intraoperative pelvic motion.

METHODS

Fifty-three patients with osteoarthritis undergoing THA in the supine position were included. Clinical factors, such as age, BMI, and pelvic tilt were assessed preoperatively. Intraoperative pelvic motion in the axial and sagittal planes was assessed using a portable navigation system. We assessed the change in pelvic tilt from registration to cup implantation as the pelvic tilt change; positive values indicated anterior pelvic tilt. We measured the values and absolute values of changes in axial rotation from registration to cup implantation to determine the axial rotation angle. The effects of patient factors on pelvic motion (pelvic tilt change and axial rotation angle) were analyzed using a Spearman's correlation analysis.

RESULTS

Preoperative pelvic tilt was negatively correlated with pelvic tilt change (r = -0.57, p < 0.05) and the absolute axial rotation angle (r = -0.57, p < 0.05). BMI and absolute axial rotation angle were negatively correlated (r = -0.54, p < 0.05). Age was not correlated with change in the pelvic tilt and the axial rotation angle.

CONCLUSIONS

Preoperative pelvic tilt and BMI are important factors to determine intraoperative pelvic motion in patients who undergo THA in the supine position. This can help surgeons to preoperatively identify patients with a higher risk of intraoperative pelvic motion.

Accuracy of cup orientation and learning curve of the accelerometer-based portable navigation system for total hip arthroplasty in the supine position

PURPOSE

To assess the accuracy of cup orientation and learning curve of the disposable accelerometer-based portable navigation system for total hip arthroplasty (THA) in the supine position.

METHODS

A total of 75 patients who underwent THA through the anterolateral supine approach (ALS) with an accelerometer-based portable navigation system for the supine position (HipAlign^®) between July 2017 and October 2018 were analyzed in this study. We compared the intraoperative cup angles using navigation records with the postoperative angles using postoperative computed tomography (CT) data. All patients were categorized into the following groups according to the course of three discrete, sequential operative time periods: 1-25 (initial group), 26-50 (intermediate group), and 51-75 (recent group). We compared the accuracy of cup inclination and anteversion among the three groups. The time required for navigation and the operative time of all patients were measured.

RESULTS

The average absolute error in measurement (postoperative CT-navigation record) was 2.6° ± 2.7° (inclination) and 2.8° ± 2.7° (anteversion). There were no significant differences among the three groups. The average time required for navigation and the operative time were 365.1 ± 90.3 s and 76.1 ± 1.6 min, respectively. The required time for HipAlign^® navigation and operative time were constant in most patients, except for those of the initial five cases.

CONCLUSION

The accelerometer-based portable navigation system provides good accuracy of cup orientation, has a short learning curve, and requires a minimal surgical time for THA in supine position.

Factors Influencing the Outcomes of Artificial Hip Replacements

Hip replacement is one of the most successful surgeries in the clinic for the removal of painful joints. Hip osteoarthritis and femoral head necrosis are the 2 main reasons for hip replacement. Several factors are associated with the outcomes of surgery. Nonsurgical factors include gender, age, body mass index, prosthetic material, and risk factors. Surgical factors are anesthesia, postoperative complications, and rehabilitation. Considering the increasing demand for hip arthroplasty and the rise in the number of revision operations, it is imperative to understand factor-related progress and how modifications of these factors promotes recovery following hip replacement. In this review, we first summarize recent findings regarding crucial factors that influence the outcomes of artificial hip replacement surgery. These findings not only show the time-specific effect for the treatment and recovery from hip arthroplasty in the clinic, but also provide suitable choices for different individuals for clinicians to consider. This, in turn, will help to develop the best possible postoperative program for specific patients.