Intellijoint Surgical (Canada)

Studies on diversity in orthopaedic surgery have exclusively examined challenges from a race or sex perspective. This study examines trends in the diversity of entering orthopaedic surgery residents from the intersection of race and sex. The American Association of Medical Colleges was queried for individuals entering orthopaedic surgery residencies in the United States from 2001 to 2020. Deidentified data on self-reported sex and race were collected. Proportions by the intersection of sex and race were calculated for 5-year intervals. From 2001 to 2020, most of the new female residents identified as White (mean, 71.0%). The average proportion of White female residents was lower in 2016 to 2020 than in 2001 to 2005 (71.0% vs. 73.2%) but higher than that in 2011 to 2015 (66.8%). The 2016 to 2020 average was lower than that of 2001 to 2005 for those who identified as Asian (11.7% vs. 14.9%), Black (4.1% vs. 4.8%), Hispanic (3.0% vs. 4.4%), and American Indian/Alaska Native (0.0% vs. 1.5%). Most of the new male orthopaedic surgery residents from 2001 to 2020 identified as White (mean, 74.1%), but the average decreased across every 5-year interval from 2001 to 2005 (76.1%) to 2016 to 2020 (71.1%). The 2016 to 2020 average was lower than that of 2001 to 2005 for those who identified as Asian (12.2% vs. 13.6%), Black (3.5% vs. 4.2%), Hispanic (3.0% vs. 3.4%), American Indian/Alaska Native (0.0% vs. 0.6%), and Native Hawaiian/Other Pacific Islander (0.1% vs. 0.3%). In 2020, White male residents made up to 54.2% of new residents. White female residents were the second highest group represented (12.1%). Increases in representation were observed for some subgroups of new orthopaedic surgery residents from 2001 to 2020. Although the proportion of both White female and male residents decreased by 11.5% during the 20-year study period, these individuals still made up most of the trainees in 2020. These results underscore the need for conversations and recruitment practices to take into consideration the intersectionality of identities.

PurposeNavigated total knee arthroplasty (TKA) improves implant alignment by providing feedback on resection parameters based on femoral and tibial cutting guide positions. However, saw blade thickness, deflection, and cutting guide motion may lead to final bone cuts differing from planned resections, potentially contributing to suboptimal component alignment. We used an imageless navigation device to intraoperatively quantify the magnitude of error between planned and actual resections, hypothesizing final bone cuts will differ from planned alignment.Materials and methodsA retrospective study including 60 consecutive patients undergoing primary TKA using a novel imageless navigation device was conducted. Device measurements of resection parameters were obtained via attachment of optical trackers to femoral and tibial cutting guides prior to resection. Following resection, optical trackers were placed directly on the bone cut surface and measurements were recorded. Cutting guide and bone resection measurements of both femoral and tibial varus/valgus, femoral flexion, tibial slope angles, and both femoral and tibial medial and lateral resection depths were compared using a Student's t-test.ResultsFemoral cutting guide position differed from the actual cut by an average 0.6 ± 0.5° (p = 0.85) in the varus/valgus angle and 1.0 ± 1.0° (p = 0.003) in the flexion/extension angle. The difference between planned and actual cut measurements for medial and lateral femoral resection depth was 1.1 ± 1.1 mm (p = 0.32) and 1.2 ± 1.0 mm (p = 0.067), respectively. Planned cut measurements based on tibial guide position differed from the actual cut by an average of 0.9 ± 0.8° (p = 0.63) in the varus/valgus angle and 1.1 ± 1.0° (p = 0.95) in slope angle. Measurement of medial and lateral tibial resection depth differed by an average of 0.1 ± 1.8 mm (p = 0.78) and 0.2 ± 2.1 mm (p = 0.85), respectively.ConclusionsSignificant discrepancies between planned and actual femoral bone resection were demonstrated for flexion/extension angle, likely the result of cutting error. Our data highlights the importance of cut verification postresection to confirm planned resections are achieved, and suggests imageless navigation may be a source of feedback that would allow surgeons to intraoperatively adjust resections to achieve optimal implant alignment.

Background: Computer-assisted navigation has the potential to improve the accuracy of cup positioning during total hip arthroplasty (THA) and prevent leg-length discrepancy (LLD). The purpose of this study was to compare acetabular cup position and postoperative LLD after primary THA using posterolateral approach. Methods: Between August 2016 to December 2017, 57 THAs using imageless navigation were matched with 57 THA without navigation, based on age, gender, and BMI. Postoperative weight-bearing radiographs were assessed for anteversion, inclination, and LLD. Functional LLD was measured in comparison to the contralateral side. The proportion of cups within Lewinnek’s safe zone and LLD greater than 5 mm were assessed. Results: The mean age was 54.9±9.6 yr and 57.6±12.5 yr in control and navigated groups, respectively. Mean cup orientation in the navigated group was 20.6±3.3 degrees (17 to 25) of anteversion and 41.9±4.8 degrees (30 to 51) of inclination, versus 25±11.1 degrees (10 to 31) and 45.7±8.7 degrees (29 to 55) in the control group; these were statistically significant (P=0.005 and P<0.001, respectively). In the navigated group, significantly more acetabular cups were placed within Lewinnek’s safe zone (anteversion: 77% vs. 47%, P=0.005; inclination: 91% vs. 67%, P<0.001). There was no significant difference in mean LLD in the navigation and control groups (3.2±1.5 mm vs. 4.6±3.4 mm, P=0.36), although fewer LLDs of greater than 5 mm were reported in the navigated group (7.1%) than in the control group (31.6%, P=0.007). Conclusions: The use of imageless computer-assisted navigation improved the accuracy of acetabular cup components and LLD. Level of Evidence: Level III.

Proper positioning of the acetabular cup deters dislocation after total hip arthroplasty (THA). The concept of a safe zone (SZ) for acetabular component placement was first characterized by Lewinnek et al. and furthered by Callanan et al. The SZ concept remains widely utilized and accepted in contemporary THA practice; however, components positioned in this SZ still dislocate. This study sought to characterize current mass trends in cup position identified across a large study sample of THA procedures completed by multiple surgeons. This retrospective, observational study reviewed acetabular cup position in 1,236 patients who underwent THA using computer-assisted navigation between July 2015 and November 2017. The overall mean cup position of all recorded cases was 21.8° (±7.7°, 95% CI = 6.7°, 36.9°) of anteversion and 40.9° (±6.5°, 95% CI = 28.1°, 53.7°) of inclination. For both anteversion and inclination, 65.5% (809/1236) of acetabular cup components were within the Lewinnek SZ and 58.4% (722/1236) were within the Callanan SZ. Acetabular cups were placed a mean of 6.8° of anteversion (posterior/lateral approach: 7.0°, anterior approach: 5.6°) higher than the Lewinnek and Callanan SZs whereas inclination was positioned 0.9° higher than the reported Lewinnek SZ and 3.4° higher than the Callanan SZ. Our data shows that while the majority of acetabular cups were placed within the traditional SZs, the mean anteversion orientation is considerably higher than those suggested by the Lewinnek and Callanan SZs. The implications of this observation warrant further investigation.

To the Editor, We thank Dr. Kohno for his interest in our article and for pointing out some important questions that would be beneficial to the surgeons who treat hip pain in young adults. We defined developmental dysplasia of the hip (DDH) as a lateral center-edge angle that is less than 20°, and borderline dysplasia as a lateral center-edge angle between 20° and 25°. In our study, we had four patients with DDH and 21 patients with borderline DDH. We agree with Dr. Kohno that hip symptoms for patients with DDH may be different from those in patients with femoroacetabular impingement (FAI). It is also important to note that patients with DDH can have impingement at the same time. We usually advocate pelvic osteotomy for patients with DDH and hip symptoms. The four patients with DDH in our series were offered pelvic osteotomy as a first-line treatment, but some patients are unwilling to undergo major pelvic osteotomy surgery. In a very select group of patients with symptomatic DDH, who also have impingement symptoms and are unwilling to undergo pelvic osteotomy, we may consider femoroacetabular osteoplasty surgery. As you can see from this cohort, those patients are rare. The nature of femoroacetabular osteoplasty surgery in patients with DDH is somewhat different. We do not trim the acetabulum in these patients. Instead, we repair the labrum and perform a tight capsular closure. Although we believe femoroacetabular osteoplasty surgery can have a role in a very select group of patients with mild DDH, we agree with Dr. Azboy that patients with DDH who have signs and symptoms of instability should not be treated by femoroacetabular osteoplasty but rather offered pelvic osteotomy. Thank you again for raising important questions related to our study.

Despite inaccuracies due to artifact and variations in patient positioning, anteroposterior (AP) radiographs remain the clinical standard for post-operative evaluation of component placement following total hip arthroplasty (THA). However, cup position, specifically anteversion, can be significantly affected by variations in patient positioning on an X-ray. A major cause of such artifact is unaccounted for pelvic tilt. Several methods for correcting the effects of pelvic tilt on radiographic anteversion have been proposed, with varying degrees of accuracy. The purpose of this study was to evaluate the accuracy and reliability of a commonly referenced method for correcting acetabular cup anteversion in a cohort undergoing total hip arthroplasty and determine its appropriateness for use in this population of patients. Radiographs from patients who underwent primary or revision hip arthroplasty between February 2016 and February 2017 were retrospectively reviewed. Corrected anteversion was calculated by measuring the vertical distance between the symphysis pubis and the sacrococcygeal joint, per the method outlined by Tannast et al. This symphococcygeal distance was then applied to Tannast’s nomograms to calculate the magnitude of pelvic tilt. Corrected and uncorrected anteversion values were compared to anteversion values collected intraoperatively using an imageless computer-assisted navigation device. A total of 71 cases were initially eligible for inclusion in the study. The correction method could not be applied in 44% (31/71) of the cases, chiefly due to difficulties in visualizing the required landmarks. In cases where it could be applied, corrected values correlated very poorly with navigation measurements (r = -0.07). Mean corrected anteversion (36.9°, SD: 7.4°) differed from uncorrected anteversion (25.2°, SD: 7.6°) by an average of 13.5° (p<0.001). Mean navigated anteversion (27.4°, SD: 5.7°) differed from corrected values by an average of 10.8° (p=0.16). The evaluated correction method could not be consistently applied to radiographs and did not reliably correct anteversion due to pelvic tilt in this population of patients undergoing hip arthroplasty. This correction method does not appear to be appropriate for use in this patient population.