Direct Anterior Approach Total Hip Research Articles

Good long-term outcomes for Direct Anterior Approach Total Hip Arthroplasty in South Africa

This study aims to assess long-term outcomes of Total Hip Arthroplasty (THA) through Direct Anterior Approach (DAA) in a developing country using traditional and novel Patient-Reported Outcomes. There were 522 patients (mean age, 56.5 years; 66.3% female) after mean follow-up 7.35 years. There were 13 revisions. Overall 5-year implant survival rate was 97.5%. Patient Joint Perception scores of 65.5% perceived a completely natural joint. Mean Hip Disability and Osteoarthritis Score was 89.1. Median Forgotten Joint Score-12 was 90 and modified Harris Hip Score was 88. Primary DAA THA in sub-Saharan Africa allows good clinical outcomes at minimum 5 years follow-up.

The Direct Anterior Approach Total Hip Arthroplasty Reliably Achieves "Safe Zones" for Combined Anteversion.

BackgroundIn total hip arthroplasty (THA), component position is critical to avoid instability and improve longevity. Appropriate combined femoral and acetabular component anteversion is important for improved THA stability and increased impingement-free range of motion. In direct anterior THA (DA-THA), concern has been expressed regarding the accuracy of femoral component positioning. This study seeks to quantify acetabular, femoral, and combined component orientation relative to the accepted “safe zones” in patients who have undergone DA-THA.MethodsTwenty-nine patients who had THA performed via direct anterior approach had postoperative computerized tomography scans done to assess femoral anteversion. Stem rotational alignment was measured relative to the transepicondylar axis (TEA) and the posterior condylar axis (PCA) of the femur at the knee. Acetabular abduction and version were recorded on anteroposterior pelvis radiographs.ResultsThe mean stem anteversion was 17.5° (standard deviation = 10.8°) from the TEA and 21.7° (standard deviation = 11.3°) from the PCA. Ten of 30 cups were appropriately anteverted; however, all the cups had appropriate abduction. Combined version when using the TEA resulted in 79% (23/29) of patients within the “safe zone” of 25°-50°. Pearson correlation coefficients were high for both stem anteversion from the TEA (R = 0.96) and PCA (R = 0.98); however, interobserver reliability for combined component anteversion was greater for the TEA (kappa, 0.83 vs 0.65).ConclusionsCombined anteversion within the “safe zone” was achieved 79% of the time with DA-THA. Interestingly, most of the “excessive” combined anteversion appears to be related to increased anteversion of the acetabular component with only 10 patients within the acetabular cup “safe zone” of 5°-25°.

Correction to: Biomechanical reconstruction parameters obtained after direct anterior approach total hip arthroplasty do not compromise clinical outcome

The original version of this article unfortunately contained a mistake. Figures3 and 4 captions were interchanged.

Clinical and Radiographic Outcomes after Direct Anterior Approach Total Hip Arthroplasty Using Two Specialized Surgical Tables.

BackgroundSpecialized tables for direct anterior (DA) approach total hip arthroplasty (THA) have required an unscrubbed assistant for manipulation of the operative limb. A novel surgical table attachment designed for the DA approach is fully surgeon controlled and partially automated. The purpose of this study is to compare the clinical outcomes in patients who underwent THA through a DA approach with an assistant-controlled vs the surgeon-controlled (SC) table.MethodsThis is a retrospective study of 343 patients who underwent primary THA between January 2017 and October 2017. Two cohorts were established based on the surgical table used. Surgical and clinical data included the surgical time, length of stay, presence of pain (groin, hip, or thigh pain) at latest follow-up, and revision for any reason. Immediate postoperative radiographs were compared with latest follow-up radiographs to assess for leg length discrepancy, stem alignment, and stem subsidence.ResultsOne hundred sixty-seven (48.7%) cases were performed using the assistant-controlled table, and 176 (51.3%) cases were performed using the SC table. The surgical time was significantly greater for surgeries using the SC table (70.2 minutes vs 66.1 minutes, P < .001). Neither group experienced any intraoperative fractures or postoperative dislocations. There were no significant differences in any other clinical or radiographic outcomes.ConclusionsAlthough the surgical time with the self-controlled table was longer by approximately 4 minutes, this discrepancy disappeared with progression through the learning curve. In our experience, the SC table allows for greater autonomy for the operating surgeon and eliminates the need for a full-time employee in the operating room workflow.

A survey of Hip Society surgeons concerning the direct anterior approach total hip arthroplasty.

To establish whether there was a consensus among the members of the Hip Society (HS) on the role of direct anterior approach (DAA) contemporary primary total hip arthroplasty (THA). An online survey was sent to all 112 active and senior members of the HS, to which 71 members responded. The survey was constructed to determine whether they believed that evidence-based medicine proves, in modern clinical practice, that the DAA has significant benefits compared to risks when contrasted with other approaches. In addition, they were asked if they currently used the DAA. While only 16.9% (12/71) of respondents had been trained in a generic anterior approach during residency, 49.3% (35/71) had used the DAA in their clinical practice in the past or were using it at the present time. Unexpectedly, 42.9% (15/35) of respondents who had used the DAA in the past had abandoned it by the time of this survey. Only 22.5% (16/71) of all respondents believed that evidence-based medicine proves that the DAA has significant benefits compared to risks in contrast to other approaches. A comprehensive literature review found only three prospective randomized clinical trials (RCT) comparing the DAA with another approach with greater than one-year follow-up. Two showed minor benefits within the early postoperative period only, and one of those showed poorer mid-term results. Most of the published comparison studies with short follow-up show longer surgical times and greater blood loss for the DAA, and many three-month comparison studies show higher complication rates for the DAA using a proprietary traction table. The complications included problems with wound healing, lateral femoral cutaneous nerve injury, femoral component loosening, and femoral fractures. Because of the lack of evidence from RCTs showing superiority of the DAA over other approaches and reports of higher complications, the opinion of a large majority (77.5%; 55/71) of HS surgeons was that the DAA lacks sufficient evidence to warrant its use. Cite this article: Bone Joint J 2020;102-B(7 Supple B):57-61.

Dimensional Changes of Lumbar Intervertebral Foramen in Direct Anterior Approach-Specific Hyperextension Supine Position.

ObjectiveTo investigate the changes in the lumbar intervertebral foramen (LIVF) dimensions from neutral supine to direct anterior approach (DAA)‐specific hyperextension supine position through a standardized three‐dimensional (3D) reconstruction computerized tomography (CT) method.MethodsA total of 35 healthy volunteers (18 men and 17 women) were included in this retrospective study. The mean age of enrolled subjects was 28.9 ± 5.0 years. In September 2018, all the individuals underwent a 3D CT scan of the lumbar spine in neutral and 30° hyperextension supine positions, which mimicked the patient’s position in DAA total hip arthroplasty (THA). The dimensions of the LIVF, including foraminal area, height, and width, were measured on 3D reconstructed CT models at all lumbar foraminal levels. Foraminal area was defined as the area bounded by the adjacent superior and inferior vertebral pedicles, the posterosuperior boundary of the inferior vertebral body, the surface of the intervertebral disc posteriorly, the posteroinferior boundary of the superior vertebral body, and the surface of the ligamentum flavum anteriorly. Foraminal height was defined as the longest distance between the border of the superior and the inferior pedicle. Foraminal width was defined as the shortest distance between the posteroinferior edge of the superior vertebrae and the opposing boundary. Subgroup analysis and multiple linear regression were used to evaluate the relationship between percentage changes of the LIVF dimensions and side, sex, and age.ResultsThe LIVF dimensions varied significantly between the two positions at all levels (P < 0.05). From neutral to hyperextension supine position, the foraminal area reduced by 20.1% at lumbar 1–2 (L1–2), 22.6% at L2–3, 19.9% at L3–4, 18.1% at L4–5, and 12.0% at lumbar 5–sacral 1 (L5–S1) level, respectively; the foraminal height reduced by 9.5% at L1–2, 10.5% at L2–3, 9.5% at L3–4, 9.6% at L4–5, and 6.1% at L5–S1 level, respectively; the foraminal width reduced by 12.8% at L1–2, 14.5% at L2–3, 13.0% at L3–4, 10.4% at L4–5, and 8.4% at L5–S1 level, respectively. The changes in LIVF dimensions were biggest at L2–3 level and smallest at L5–S1 level. Subgroup analysis showed that there were no significant differences in the percentage changes of LIVF dimensions between the sexes and sides (P > 0.05). Multiple linear analysis showed that the percentage changes of LIVF dimensions were not related to side, sex, and age (P > 0.05).ConclusionThe dimensions of the LIVF showed significant decrease at all levels in the DAA‐specific hyperextension supine position compared with the neutral supine position, and the percentage changes of LIVF dimensions were not influenced by side, sex, and age.

Early Experience of Direct Anterior Approach Total Hip Arthroplasty: Analysis of the First 53 Cases.

PurposeTo determine if it is feasible and safe for a surgeon to transition from using the posterolateral approach to direct anterior approach (DAA) by evaluating the first 53 cases of total hip arthroplasty using a DAA.Materials and MethodsA retrospective review of 52 patients who underwent THA using a DAA between July 2017 and December 2018. Reasons for THA were: femoral neck fracture (n=34), avascular necrosis (n=13), and arthritis (n=6). The mean age was 70 years old. An assessment of feasibility was made by analyzing mean operative time and blood loss. Cup inclination, anteversion, and leg length discrepancy (LLD) were measured using postoperative radiology. Safety of the DAA was judged using the incidence and nature of all complications.ResultsThe mean operative time was 112 minutes. 135 minutes for the 1st 10 cases, 100 minutes for 2nd 10 cases, 113 minutes for 3rd 10 cases, 119 minutes for 4th 10 cases, and 91 minutes for the final 13 cases. The mean blood loss was 724 mL. Average cup inclination was 40.27°; 2 cases were out of safety angle. Mean anteversion was 16.18°. No intraoperative fractures or infections were observed. LLD was detected in 3 cases, one of which underwent revision due to walking difficulty. Dislocation occurred in 3 cases, all within the first 20 cases, however, there was no recurrent dislocation.ConclusionDAA for THA was deemed to be feasible and safe based on an assessment of operative time, blood loss and complications.

Direct Anterior Approach in Crowe Type III-IV Developmental Dysplasia of the Hip: Surgical Technique and 2 years Follow-up from Southwest China.

ObjectivesTo summarize our pioneering surgical practice and clinical outcome of Crowe type III‐IV developmental dysplasia of the hip (DDH) with a direct anterior approach total hip arthroplasty in a single teaching hospital in Southwest China.MethodsFourteen patients (15 hips) diagnosed with Crowe type III‐IV developmental dysplasia of the hip were involved in this single‐center retrospective study between 2016 and 2018. A comprehensive surgical procedure, including preoperative planning and algorithms for leg length equalization, intraoperative stepwise soft tissue release, bone defect reconstruction, and an innovative subtrochanteric osteotomy, was described. Furthermore, advancements in intraoperative CT guidance, computer navigation, and nerve monitoring were available for specific demands. The short‐term clinical outcome was evaluated at the endpoint of follow‐up by three patient‐reported functional scales (Harris, WOMAC, and SF‐12 scores), and objective data collected at the clinic, including functional recovery (muscle strength of hip flexor and abductor, correction of the pelvic tilt, leg length discrepancy, and limp), radiographic analysis, and complication occurrence.ResultsThe intraoperative variables were carefully recorded. The mean operating times in Crowe type III and IV groups were 115.8 min and 156.2 min, and the median blood loss volumes were 520.5 mL and 810.2 mL, respectively. The general changes in the Harris, SF‐12, and WOMAC scores of the two groups were 46.2, 8.7 and 134.3, respectively, at a mean follow‐up of 25.4 months. Enhanced recovery of hip abductor muscle strength was identified in 85.7% of the population at the third postoperative month. The equalization of leg length and correction of the pelvic tile were observed at the sixth postoperative month, with a 36‐mm decrease in leg length discrepancy. No radiographic evidence of the loosening or migration of the components was observed. A self‐innovated subtrochanteric shortening osteotomy was performed in five patients, and they healed after 6 months. Specific complications included two cases of distal femoral cracks and one case of a periprosthetic fracture needing internal fixation. Two patients received a late iliotibial band release at the 3rd month postoperatively due to progressive genu valgum. No records of infection, dislocation, nerve palsy, bone non‐union, or revision surgery were identified.DiscussionThe direct anterior approach total hip arthroplasty showed potential advantages, including optimum component positioning, improved hip stability, steerable complication rate, and enhanced functional recovery with Crowe type III‐IV DDH. The short‐term outcome is comparable to that of the traditional posterolateral approach.

Functional outcomes of direct anterior approach hip arthroplasty: Oblique ‘bikini’ versus longitudinal skin incision

Introduction: The direct anterior approach (DAA) for hip arthroplasty has gained popularity in recent years with numerous articles suggesting that short-term outcomes are advantageous over alternative approaches. The ‘bikini’ inguinal crease line incision is a novel variant of the DAA, which reduces the scar. Methods: We conducted a retrospective cohort study to assess functional and general health outcomes and complications of the two different surgical incisions used in DAA total hip arthroplasty (i.e. ‘bikini’ and longitudinal incisions). Results: We found no statistical difference between the novel bikini incision and the traditional DAA hip arthroplasty. Conclusion: This approach offers a cosmetically improved scar with no compromise in outcomes.

Direct anterior approach total hip arthroplasty for Crowe III and IV dysplasia.

High-dislocated hip dysplasia is challenging to treat with total hip arthroplasty via the direct anterior approach (DAA). The DAA has potential advantages including optimizing component positioning, enhanced hip stability, and a more rapid postoperative recovery. We present a surgical technique for DAA total hip arthroplasty for hip dysplasia that includes preoperative planning, soft tissue releases, subtrochanteric osteotomy, component placement, and intraoperative nerve monitoring and imaging. This technique provides detailed technical instructions, specifically including pearls and pitfalls, and complication prevention strategies.

Short-Term Radiographic Evaluation of a Tri-Tapered Femoral Stem in Direct Anterior Total Hip Arthroplasty

Direct anterior approach (DAA) total hip arthroplasty (THA) has become increasingly popular, largely due to utilization of a true internervous and intermuscular plane. However, recent literature has demonstrated an increased rate of femoral implant subsidence with this approach. Hence, different femoral implants, such as the tri-tapered femoral stem, have been developed to facilitate proper component insertion and positioning to prevent this femoral subsidence. The purpose of this study was to evaluate the subsidence rate of a tri-tapered femoral stem implanted utilizing a DAA, and to determine if the proximal femoral bone quality affects the rate of subsidence. A retrospective analysis of 155 consecutive primary THAs performed by a single surgeon was conducted. Age, gender, primary diagnosis, and radiographic measurements of each subject were recorded. Radiological evaluations, such as bone quality, femoral canal fill, and implant subsidence, were measured on standardized anteroposterior (AP) and frog-leg lateral radiographs of the hip at 6-week and 6-month postoperative follow-up evaluations. The average subsidence of femoral stems was 1.18 ± 0.8 mm. There was no statistical difference in the amount of subsidence based on diagnosis or proximal femora quality. The tri-tapered stem design consistently filled the proximal canal with an average of 91.9 ± 4.9% fill. Subsidence was not significantly associated with age, canal flare index (CFI), or experience of the surgeon. THA utilizing the DAA with a tri-tapered femoral stem can achieve consistent and reliable fit regardless of proximal femoral bone quality.

Perioperative Fracture Risk and Two-Year Survivorship of a Short Tapered Femoral Stem following Direct Anterior Approach Cementless Total Hip Arthroplasty with a Fracture Table

AbstractThe cementless, tapered wedge, short femoral stem implant is commonly used in direct anterior approach (DAA) total hip arthroplasty (THA). The lack of access and visualization, however, may increase the risk of perioperative fracture and early failure. Therefore, the current study examined perioperative complications and 2-year implant survivorship following DAA THA performed using a fracture table and short, tapered wedge femoral stem. A retrospective analysis was conducted on patients having undergone DAA THA with a cementless, tapered wedge, short femoral stem. Perioperative fractures were noted and survivorship was determined by the incidence of revision surgery within a minimum 2-year follow-up period. A total 366 consecutive patients (441 hips) were identified in the cohort. Four patients (6 hips; 1.4%) were lost to follow-up and three patients died from unrelated causes. Average follow-up time for the remaining 359 patients (435 hips) was 32.9 ± 10.2 months. There were no intraoperative factures but three perioperative fractures within two weeks. Aseptic loosening occurred in one stem at 13 months, resulting in a 99.1% survival rate with a mean survival time of 23.8 ± 0.1 months (95% confidence interval: 23.6–24.0 months). The use of a short, tapered wedge femoral stem and a fracture table for DAA THA resulted in 0.7% periprosthetic fractures and only one aseptic loosening within 2 years. These results suggest that proper femoral exposure with the use of a fracture table and a short, tapered wedge femoral stem does not appear to increase the risk of periprosthetic femoral fracture.

Simultaneous Bilateral Minimally Invasive Direct Anterior Approach Total Hip Arthroplasty with fast track Protocol.

Advanced degenerative hip joint disease is bilateral in approximately 20% of cases, prompting questions of whether it is necessary to perform two separate surgical procedures, whether simultaneous bilateral hip replacement makes the surgical treatment too extensive, and whether it significantly affects the postoperative course. The study analysed the duration of hospitalisation, perioperative complications, and the need for blood transfusion in 30 patients (27 men and 3 women) with bilateral hip osteoarthritis who underwent simultaneous bilateral total hip replacement from a minimally invasive direct anterior approach followed by a fast track protocol for optimisation of perioperative management between 2014 and 2017. The mean age of patients was 60.2 years (range 43 to 77 years) and the mean follow-up period was 28 months (range 18 to 48 months). Mean duration of hospitalisation was 4.5 days (range 3 to 9 days). A total of 4 patients (13%) required allogeneic blood transfusion. No patient developed thromboembolic or infectious complications or implant dislocation after surgery. Apart from one case where the acetabulum was not selected correctly, which resulted in postoperative loosening, there were no other significant medical events potentially related to the surgical treatment. Simultaneous bilateral total hip arthroplasty using a minimally invasive direct approach and a fast track protocol for optimisation of perioperative management does not increase the need for perioperative blood transfusion or the number of surgical complications and constitutes a safe, effective, and recommendable method of treatment in patients with advanced bilateral degenerative disease of the hip joints.

Direct Anterior Approach Total Hip Arthroplasty Revisited.

In total hip arthroplasty, the advantages of the direct anterior approach (DAA) compared with the direct lateral and posterior approaches include a true intermuscular approach that spares the abductor musculature, protects the soft tissues surrounding the hip, and thus maintains hip joint stability. The disadvantages of the DAA compared with the direct lateral and posterior approaches include a steep learning curve; intraoperative radiation exposure; injury to the nerves, vessels, and muscles; and intraoperative and early postoperative complications including blood loss, wound-healing problems, increased time under anesthesia, proximal femoral fractures and dislocations, complex femoral exposure and bone preparation, and sagittal malalignment of the stem leading to loosening and an increased revision rate. Stem implantation in flexed sagittal position and early femoral-stem failures are more common with the DAA compared with the direct lateral and posterior approaches.

Algorithmic soft tissue femoral release in anterior approach total hip arthroplasty.

Although the anterior approach for total hip arthroplasty has gained increasing utilization, some studies have suggested a higher risk of femoral complications, as well as difficulty with femoral exposure. Techniques of soft tissue releases have been described to offer better femoral exposure, and to help mitigate complications. The purpose of the study is to describe an algorithmic soft tissue femoral release in direct anterior approach total hip arthroplasty and to assess the clinical outcomes of patients upon which this algorithm of femoral soft tissue releases was utilized. Clinical outcomes with the Harris Hip Score, reoperation rates, component survivorship, and complications were analyzed.

Heterotopic Ossification after Direct Anterior Approach Total Hip Arthroplasty

AbstractPrevious studies have demonstrated varying rates of heterotopic ossification (HO) after total hip arthroplasty (THA) depending on which anatomical approach is utilized. The direct anterior approach (DAA) is considered to be a muscle-sparing approach to the hip, which may lead to decreased rates of HO formation. This study evaluated the incidence of HO formation after DAA THA. The current work is a retrospective review of patients who underwent DAA THA. Six-month postoperative radiographs were evaluated and HO grade was classified using the Brooker classification system. Baseline characteristic differences between the Brooker classification groups were analyzed, specifically looking at: age, sex, type of deep venous thrombosis prophylaxis utilized, and preoperative Bombelli arthritis type. The overall incidence of HO in this DAA group was 179/485 patients (36.9%). There were 14 patients (2.9%) with Brooker Type 3 HO and 1 patient (0.21%) with Brooker Type 4 HO. No surgical excision of HO was performed. Patients were significantly more likely to develop HO if they had Bombelli hypertrophic arthritis (p &lt; 0.00003). Preoperative radiographic imaging suggesting Bombelli hypertrophic arthritis is predictive of HO formation, warranting consideration for HO prophylactic treatment. The radiographic incidence of HO in DAA THA was 36.9%, which is within the previously reported range of HO seen for lateral and posterior approaches to the hip. HO after total hip arthroplasty is likely due to soft tissue handling, hemostasis, and patient factors, rather than type of surgical approach.

Hospital Adverse Events and Perioperative Outcomes in Bilateral Direct Anterior Approach Total Hip Arthroplasty

BackgroundPerioperative hospital adverse events represent a significant outcome that is often overlooked. Even “minor events” such as fever or tachycardia may lead to significant costs due to workup tests, interconsultations, and/or increased length of stay (LOS). The optimal timing of bilateral direct anterior approach total hip arthroplasty (DAA-THA) remains unsettled. Consequently, we wanted to compare hospital LOS, discharge disposition, hospital adverse events (major and minor), and transfusion rates between simultaneous and staged bilateral DAA-THA. MethodsA retrospective chart review was conducted on a consecutive series of 347 primary bilateral DAA-THAs (204 patients) performed by 2 surgeons in a single institution (2010-2016). The hips finally included were categorized as simultaneous (Sim-n = 61), staged 1 (Stg1-n = 143), or staged 2 (Stg2-n = 143). We also compared simultaneous with staged surgeries performed ≤1 and >1 year apart. Baseline demographics, LOS, discharge disposition, hospital adverse events, and transfusions were assessed. ResultsThe simultaneous group had significantly younger patients and a higher proportion of males when compared with the staged groups and showed significant longer LOS [2.61 (Sim) vs 2.06 (Stg1) vs 1.63 (Stg2) days, P < .001], lower proportion of home discharge [77% (Sim) vs 91.6% (Stg1) vs 96.5% (Stg2), P < .001], as well as higher (overall) rate of adverse events [31.1% (Sim) vs 28.7% (Stg1) vs 14.0% (Stg2), P = .003] and transfusions [45.9% (Sim) vs 6.3% (Stg1) vs 7.0% (Stg2), P < .001]. However, most transfusions were autologous [37.7% (Sim) vs 3.5% (Stg1) vs 0% (Stg2), P < .001]. ConclusionOur data show that bilateral DAA-THAs performed in a staged fashion, rather than simultaneously, have a shorter hospital LOS and decreased rates of adverse events and overall transfusions. Notwithstanding, simultaneous surgery should still be considered an option in selected patients. Level of EvidenceLevel III.

Anterior versus posterior approach total hip arthroplasty: patient-reported and functional outcomes in the early postoperative period.

Direct anterior approach total hip arthroplasty (DA THA) has been reported to improve early outcomes compared to posterior approach THA up to 6 weeks postoperatively. Limited weekly outcomes data are available prior to 6 weeks. We evaluate outcomes including when patients first drive a car, leave home, and discontinue their assist device. Patients undergoing THA for primary osteoarthritis were prospectively enrolled. Outcomes data were collected preoperatively and postoperatively at weekly intervals for 6 weeks. 111 patients (55 DA and 56 posterior approach) were enrolled. There was no significant difference (p > 0.05) in pre-surgical Patient-Reported Outcomes Measurement Information System (PROMIS) scores or modified Harris Hip Score (mHHS).Postoperatively, the DA THA group had decreased length of stay (p = 0.0002) and increased distance walked on postoperative day 1 and 2 (p = 0.011, p = 0.0004). The DA group had lower pain scores (p < 0.05) and required less day 1 and total narcotics (p = 0.029, p = 0.01). The DA cohort had improved PROMIS Physical Function scores and mHHS up to 5 weeks postoperatively. DA patients discontinued their assistive device 8 days earlier (p = 0.01), left home 3 days earlier (p = 0.001), and drove a car 5 days earlier (p = 0.01). Patients undergoing DA THA discontinued their assistive device, left their home, and drove a car sooner than posterior approach patients. We found improvement in physical function with DA, and it persisted up to 5 weeks postoperatively. Furthermore, DA patients had significantly shorter length of stay, improved mobilisation, decreased narcotic requirements and improved inpatient pain scores compared to posterior approach THA. Future randomised controlled study should be performed to minimise the biases inherent in this study methodology and confirm the results.

Prospective Evaluation of the Posterior Tissue Envelope and Anterior Capsule After Anterior Total Hip Arthroplasty

BackgroundFemoral exposure for direct anterior approach (DAA) total hip arthroplasty (THA) invariably requires posterior soft tissue releases. Released posterior structures cannot be repaired. The purpose of this study is to describe the frequency and anatomic consequences of DAA THA posterior soft tissue releases and to compare the appearance of the anterior capsule between a group of patients who had capsulotomy and repair versus capsulectomy. MethodsThirty-two DAA THA patients underwent metal artifact reduction sequence magnetic resonance imaging at discharge and 1-year follow-up. Seventeen had underwent capsulotomy and repair and 15 capsulectomy. A radiologist blinded to intraoperative data scored each metal artifact reduction sequence magnetic resonance imaging. Anterior capsular integrity, status of the piriformis and conjoint tendons, and muscle atrophy were graded. Descriptive statistics were performed to analyze results. ResultsImmediately postoperatively, 75% of piriformis tendons were intact and 38% of conjoined tendons were intact. At 1 year, 97% had an intact piriformis and conjoined tendon, although many were in continuity through scar with the capsule. The posterior capsule directly contacted bone in all patients. At 1 year, none of the patients who underwent capsulotomy with repair had persistent anterior capsule defects, while 27% in the capsulectomy group had persistent defects. ConclusionPosterior capsule and conjoined tendon releases were commonly performed during DAA THA, yet continuity with bone was frequently achieved at 1 year. In this study, capsulotomy with repair resulted in no anterior capsular defects when compared with capsulectomy. These results may support improved THA stability observed after DAA with capsular repair despite posterior soft tissue releases. Level of EvidenceLevel III, prospective cohort study.

Are single plane intraoperative and biplanar postoperative radiographic measurements of acetabular cup position the same?

Supine positioning and the use of fluoroscopy during direct anterior approach total hip arthroplasty (DAA THA) have been reported to improve acetabular component positioning. This study aims to compare 2-dimensional intraoperative radiographic RadLink measurements of acetabular component position with 3-dimensional postoperative 3D SterEOS measurements. Intraoperative fluoroscopy and RadLink (El Segundo, CA, USA) were used to measure acetabular cup position intraoperatively in 48 consecutive patients undergoing DAA THA. Cup position was measured on 6-week postoperative standing EOS images using 3D SterEOS software (EOS Imaging, SA, Paris, France) and compared to RadLink findings using Student's t-test. Safe-zone outliers were identified. We evaluated for measurement difference of > +/- 5°. RadLink acetabular cup abduction measurement (mean 43.0°) was not significantly different than 3D SterEOS in the anatomic plane (mean 42.6°, p = 0.50) or in the functional plane (mean 42.7°, p = 0.61). RadLink acetabular cup anteversion measurement (mean 17.9°) was significantly different than 3D SterEOS in both the anatomic plane (mean 20.6°, p = 0.022) and the functional plane (mean 21.2°, p = 0.002). RadLink identified 2 cups outside of the safe-zone. However, SterEOS identified 12 (anatomic plane) and 10 (functional plane) outside of the safe-zone. In the functional plane, 58% of anteversion and 92% of abduction RadLink measurements were within +/- 5° of 3D SterEOS. Intraoperative fluoroscopic RadLink acetabular anteversion measurements are significantly different than 3D SterEOS measurements, while abduction measurements are similar. Significantly more acetabular cups were noted to be outside of the safe-zone when evaluated with 3D SterEOS versus RadLink.