Orthopedics

Feature Article Supplemental Data

The Effect of Total Hip Arthroplasty Surgical Technique on Postoperative Muscle Atrophy

Edward M. Vasarhelyi, MD, MSc; Harley A. Williams, BSc; James L. Howard, MD, MSc; Stephen Petis, MD, MSc; Joseph Barfett, MD, MSc; Brent A. Lanting, MD, MSc

Abstract

A variety of surgical approaches are used for total hip arthroplasty (THA). Controversy still exists regarding whether the direct anterior approach truly minimizes muscle damage. The purpose of this study was to determine the effect of surgical approach for THA on muscle atrophy quantified through magnetic resonance imaging (MRI). The study included 25 hips in patients with a mean age of 64.72±8.35 years who underwent a primary unilateral THA for severe osteoarthritis. Patients were grouped according to surgical approach: direct anterior (n=9), direct lateral (n=9), and posterior (n=7). Magnetic resonance images were collected at the 24-week postoperative time point to assess atrophy/fatty infiltration of the hip musculature. All MRIs were assessed by a fellowship-trained radiologist who was blinded to all clinical information. There were no significant differences preoperatively and 1 year postoperatively between the surgical approach groups in terms of patient-reported outcome measures (P>.05). Significant differences in fatty infiltration differences between surgical approaches were observed in the gluteus medius, gluteus minimus, iliacus, obturator externus, obturator internus, pectineus, psoas, quadratus femoris, sartorius, and vastus intermedius (P<.05). The direct anterior approach to THA resulted in less atrophy of the hip musculature compared with a direct lateral or posterior approach; however, there were no differences in patient-reported clinical outcome scores at 1 year between the surgical approaches. [Orthopedics. 2020;43(6):361–366.]

Abstract

A variety of surgical approaches are used for total hip arthroplasty (THA). Controversy still exists regarding whether the direct anterior approach truly minimizes muscle damage. The purpose of this study was to determine the effect of surgical approach for THA on muscle atrophy quantified through magnetic resonance imaging (MRI). The study included 25 hips in patients with a mean age of 64.72±8.35 years who underwent a primary unilateral THA for severe osteoarthritis. Patients were grouped according to surgical approach: direct anterior (n=9), direct lateral (n=9), and posterior (n=7). Magnetic resonance images were collected at the 24-week postoperative time point to assess atrophy/fatty infiltration of the hip musculature. All MRIs were assessed by a fellowship-trained radiologist who was blinded to all clinical information. There were no significant differences preoperatively and 1 year postoperatively between the surgical approach groups in terms of patient-reported outcome measures (P>.05). Significant differences in fatty infiltration differences between surgical approaches were observed in the gluteus medius, gluteus minimus, iliacus, obturator externus, obturator internus, pectineus, psoas, quadratus femoris, sartorius, and vastus intermedius (P<.05). The direct anterior approach to THA resulted in less atrophy of the hip musculature compared with a direct lateral or posterior approach; however, there were no differences in patient-reported clinical outcome scores at 1 year between the surgical approaches. [Orthopedics. 2020;43(6):361–366.]

Considered to be one of the most successful and frequently performed orthopedic procedures, total hip arthroplasty (THA) is the standard of care treatment for severe degeneration of the hip joint. Although significant advances in implant design and instrumentation have been observed during the past decades, the surgical approaches to THA have remained relatively unchanged.1 Surgical approach, with a focus on minimally invasive techniques, has become an area of increasing interest in the literature and the orthopedic community.

It is estimated that in 2015 to 2016, 169,060 THAs were performed in the United States and 53,207 in Canada.2–4 A recent survey of surgeons worldwide found that the most common approach is the posterior approach, followed by the direct lateral and anterior approaches.5 United States data suggest the same trend in approaches.5 However, in Canada, approximately 60% are conducted using a direct lateral surgical approach, 34% using a posterior approach, and less than 5% using a direct anterior approach.4,6 Each approach is accompanied by a varying array of advantages and disadvantages. For instance, relative risk of intraoperative fracture or nerve injury and postoperative complications such as hip dislocation and abductor insufficiency vary depending on approach used.7

The direct lateral and posterior approaches are similar in that they both involve splitting of the hip musculature.4 Nevertheless, the surgical anatomy incised differs between approaches, and as such, potential complications and patient outcomes are variable. In the direct lateral approach, the hip abductor muscles (gluteus minimus and medius) are partially released off their insertions for the surgery and subsequently repaired at wound closure.6,8 Release and repair of this musculature has been suggested to contribute to postoperative gait abnormalities, such as a Trendelenburg gait or a contralateral pelvic tilt, abductor muscle insufficiency, and peritrochanteric pain.6,9,10 The posterior approach involves the incision of the short external rotators of the hip, as well as developing an interval in the gluteus maximus, and can consequentially effect the rotatory kinetics of the lower limb. Furthermore, the posterior approach carries a higher risk of postoperative hip dislocation.6,11,12

The direct anterior approach is advocated by some surgeons because of its intermuscular, internervous surgical plane. The direct anterior approach takes advantage of the internervous plane between the tensor fascia lata (TFL) and sartorius superficially and the rectus femoris and gluteus medius deep to access the anterior portion of the joint capsule of the hip. Purported advantages of the direct anterior approach, such as faster restoration of functional capabilities, less postoperative pain, and a smaller risk of a postoperative limp, have been discussed.13–15 The direct anterior approach has been associated with higher complication rates and more variable outcomes than the lateral and posterior approaches.13,16 Complications can include a greater risk of postoperative wound infection requiring reoperation, nerve palsy, and iatrogenic fracture.1,4,17 Furthermore, complications are more prevalent in obese individuals.1,4,17 Occasionally, the conjoint tendon and piriformis must be tenotomized to facilitate adequate femoral exposure in the direct anterior approach, in which case muscle damage may ensue.4 Cadaveric studies have demonstrated that even when a direct anterior approach is used, abductor muscle damage can be observed.4,18 However, these findings must be interpreted with caution because these studies were cadaveric. There is the potential that cadaveric tissue responds differently to the THA procedure than in vivo tissues as a result of differing tissue properties.19

The goal of this study was to determine the relationship between postoperative muscle atrophy, as measured through magnetic resonance imaging (MRI), and THA surgical approach. Magnetic resonance imaging is the preferred imaging modality for the assessment of postoperative soft tissue pathology and can provide an objective measurement of atrophy/fatty infiltration of the hip musculature and abductor muscle tears.4,19–21 The authors hypothesized that soft tissue changes in the short external rotators of the hip would be observed when a direct anterior or posterior approach are used, with the least amount of soft tissue change observed in the group who underwent THA under a direct anterior approach.

Materials and Methods

Ethics approval was obtained from the institutional research ethics board to recruit a subset of patients from a larger randomized prospective study to participate in an MRI investigation. All patients were referred to the single institution centralized arthroplasty intake system and distributed to 1 of 3 participating fellowship-trained arthroplasty surgeons (E.M.V., J.L.H., B.A.L.). The patients were then recruited from the clinic of 1 of the 3 participating fellowship-trained arthroplasty surgeons. All patients received identical implants (Corail/Pinnacle; DePuy, Warsaw, Indiana).

Patients were included if they had primary osteoarthritis of the hip; consented for a unilateral THA through an anterior, lateral, or posterior approach; were older than 19 years; and did not meet any of the exclusion criteria. Exclusion criteria were a body mass index (BMI) greater than 45 kg/m2, posttraumatic osteoarthritis, rheumatoid arthritis, dementia or other cognitive disorder, alcoholism, prior hip surgery, cemented THA, simultaneous bilateral THA, use of implants other than those standardized for the study, inadequate understanding of the English language, inability to complete the gait analysis testing, inability to undergo an MRI because of contraindicated metallic implants (eg, internal defibrillators, metallic coils), Legg-Calves-Perthes disease, slipped capital femoral epiphysis (SCFE), and developmental dysplasia of the hip (DDH).

After informed consent was obtained, patient demographic and surgical characteristics were collected. The Short-Form 12 (SF-12) questionnaire, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questionnaire, and Harris Hip Score (HHS) were collected preoperatively. Following hospital discharge, patients followed up with each arthroplasty surgeon at 2, 6, and 12 weeks postoperatively. At the 6- and 12-week visits, patients performed the Timed Up and Go (TUG) test, HSS, WOMAC, and SF-12 questionnaire.

At the 24-week mark, patients underwent MRI of the involved limb to assess postoperative soft tissue and bony changes. Magnetic resonance imaging sequences for each hip included a 3-plane localizer, sagittal short tau inversion recovery (STIR), coronal proton density, axial T2, axial STIR, coronal T1, and coronal STIR.

Patient-reported outcome measures were collected preoperatively and 1 year postoperatively. The SF-12 was used to assess physical and mental health and well-being. The WOMAC was used as a disease-specific assessment. The HHS was used as a joint-specific clinician-based outcome measure.

Patient demographic data, MRI results, and pre- and postoperative clinical outcome scores were presented as frequencies or means and standard deviations where appropriate. Statistical differences between the surgical approaches at baseline and between quantitative MRI results were evaluated using one-way analysis of variance or multivariate analysis of covariance. All statistical analysis was done using SPSS, version 24, software (IBM SPSS Inc, Chicago, Illinois). P≤.05 was deemed to be significant.

Results

The mean age of the entire sample was 64.72±8.35 years, and 12 (48%) were female. The sample consisted of 12 (48%) right hips and 13 (52%) left hips. There were no significant differences between the surgical approach groups in terms of age, sex, height, weight, BMI, or operative limb. Patient baseline characteristics are presented in Table 1.

Patient Demographics at Baseline

Table 1:

Patient Demographics at Baseline

Patient-reported outcome measures were collected and analyzed at baseline (n=23) and at the 1-year postoperative time point (n=22). No significant differences were present at baseline or 1 year postoperatively between the 3 surgical approach groups. Outcome scores for the cohorts are presented in Table 2. Scores for each approach separately can be found in Table A, Table B, and Table C (available in the online version of the article).

Patient-Reported Outcomes at Baseline and 1 Year Postoperatively

Table 2:

Patient-Reported Outcomes at Baseline and 1 Year Postoperatively

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct anterior approach group. Presented as mean ± standard deviation.

Table A:

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct anterior approach group. Presented as mean ± standard deviation.

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct lateral approach group. Presented as mean ± standard deviation.

Table B:

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct lateral approach group. Presented as mean ± standard deviation.

Average Patient Reported Outcomes at baseline and one year post-operatively for the posterior approach group. Presented as mean ± standard deviation.

Table C:

Average Patient Reported Outcomes at baseline and one year post-operatively for the posterior approach group. Presented as mean ± standard deviation.

Individual muscles, including adductor brevis, adductor longus, adductor magnus, gluteus maximus, gluteus medius, gluteus minimus, iliacus, inferior gemellus, obturator externus, obturator internus, pectineus, piriformis, psoas, quadratus femoris, rectus femoris, sartorius, TFL, vastus intermedius, and vastus lateralis, were isolated by region of interest in each hip, and histograms were assessed for intensity. A higher intensity score is indicative of more fat infiltration of the respective muscle. The adductor brevis, longus, and magnus were used as covariates in the statistical analysis to quantify preoperative fatty atrophy. The inferior gemellus was excluded from the main group analysis because intensity readings were only available for 15 (60%) of the 25 participants due to interference from metal artifact. A subgroup analysis was conducted with the 15 subjects (direct anterior, 5; direct lateral, 4; posterior, 6). In cases where an individual had 2 intensity readings for a given muscle, an average of the 2 values was presented.

Significant differences in fatty atrophy were found between surgical approach groups for the gluteus medius, gluteus minimus, iliacus, obturator externus, pectineus, psoas, quadratus femoris, sartorius, and vastus intermedius. The direct anterior approach recorded significantly lower atrophy readings in the gluteus medius, gluteus minimus, iliacus, obturator externus, pectineus, psoas, quadratus femoris, and sartorius muscle groups compared with the direct lateral approach (P<.05). When compared with the posterior approach, the direct anterior approach recorded lower atrophy readings in the gluteus medius, iliacus, obturator externus, pectineus, psoas, sartorius, and TFL. The posterior approach reported lower intensity values when compared with the direct lateral approach in the gluteus medius, gluteus minimus, iliacus, obturator externus, obturator internus, psoas, and quadratus femoris (P<.05). However, following a direct lateral approach, less atrophy was observed in the pectineus and vastus intermedius compared with the posterior approach. The readings are presented in Table 3. The gluteus maximus and TFL reported the greatest amount of fatty infiltration. The subgroup analysis of patients with inferior gemellus readings indicated no difference in fatty infiltration of the inferior gemellus (P=.804).

Muscle Intensity Readings by Surgical Approach

Table 3:

Muscle Intensity Readings by Surgical Approach

Discussion

The goal of this study was to objectively assess the muscle atrophy, as measured by MRI, that occurs following THA via 3 common surgical approaches: direct anterior, direct lateral, and posterior. Proposed advantages minimally invasive surgical techniques include expedited recovery, reductions in blood loss and operative time, smaller incisions, and less soft tissue dissection.1 The observed results confirm the authors' hypothesis that, when compared with the direct lateral and posterior approaches, the direct anterior approach results in less fatty infiltration of the hip musculature.

Meneghini et al18 observed in cadaveric tissue that less gluteus minimus muscle atrophy and comparable gluteus medius muscle atrophy were observed following THA with a direct anterior approach compared with a posterior approach. These results agree with those of the current study, indicating that the direct anterior approach causes less abductor muscle atrophy than the posterior approach. Bergin et al14 quantified the amount of muscle atrophy between the direct anterior and posterior approaches using serum creatine kinase levels and found that significantly less muscle degeneration was observed following THA with a direct anterior approach. The current results provide an objective measurement of muscle atrophy to corroborate the changes in inflammatory markers seen immediately postoperatively. Müller et al22 reported a greater reduction in gluteus medius cross-sectional area following the direct lateral approach as compared with the direct anterior approach. In addition, they reported similar increases in cross-sectional area and changes in fatty atrophy of the TFL independent of approach. Although cross-sectional area was not assessed in the current study, fat infiltration of the TFL was found to be non-statistically different between the 3 approaches.23 This similarity was unsurprising because the 3 surgical approaches examined do not tenotomize the TFL. Thus, similar levels of intraoperative damage of TFL were expected and subsequently observed among the current cohort.

More specifically, the gluteus minimus and maximus are divided and partially tenotomized in the direct lateral approach, and within these 2 muscle groups of interest, the direct lateral approach reported the highest rates of fat infiltration. The posterior group, which involves tenotomizing the short external rotators, reported the highest rates of fatty infiltration in the pectineus and the second highest readings in the obturator externus, obturator internus, and quadratus femoris, with the lateral group being the highest. However, the direct anterior approach still recorded the lowest (rectus femoris and TFL) or equivalent (sartorius and gluteus medius) infiltration readings in the muscle groups around the internervous planes used in the approach. Muscles not specifically tenotomized in a given approach group, such as the sartorius, saw comparable levels of muscle fat infiltration postoperatively.

All patients saw improvement in clinical outcome scores postoperatively, irrespective of approach. Despite the postoperative differences identified between the surgical approach groups in terms of muscle atrophy or fatty infiltration, consistent with the literature, no significant differences in postoperative clinical outcome scores were identified between the groups at 1 year.24 This means that regardless of surgical approach used and the amount of muscle atrophy observed within the specific approach cohorts, all patients reported improvements in clinical outcome scores from a preoperative baseline to 1 year postoperatively. This may be a result of the small sample size or due to follow-up time, because most advantages of minimally invasive surgical approaches are evident in the early postoperative period.22,25,26 Nonetheless, based on larger series investigations and the current body of literature, the similarity between approaches is not surprising. Because postoperative score improvement was not observed to correlate with the extent of muscle atrophy, future work should examine alternative ways in which differences in fatty infiltration may affect postoperative function and success.

The design of this study had inherent limitations. First, this was an expertise-based study, which may impose some inherent biases due to both surgeon and patient expectation. Although randomization would have removed this potential bias, approach was determined based on surgeon experience and training rather than any predetermined patient characteristic.14 However, those responsible for determining intensity readings for the MRIs remained blinded to approach. In addition, patients did not undergo pre-operative MRI of the hip musculature to identify any degenerative changes associated with osteoarthritis that may have been present at baseline. A preoperative MRI would allow for the authors to identify what changes in muscle atrophy were specifically imparted by surgical approach and not secondary to chronic osteoarthritis. By using the adductor muscle groups as covariates in their statistical analyses, the authors attempted to control for this bias. Although all MRIs were assessed by a fellowship-trained radiologist who was blind to all clinical information, no formal assessment of intraobserver agreement was conducted. The authors did not report on the region of which average intensity readings were determined for the muscle groups of interest. Thus, the possibility that the differences between gluteus medius readings found between the anterior and lateral approaches could be greater than those reported cannot be excluded. Due to the small sample size, the authors were unable to conduct a subgroup analysis of direct anterior patients who had soft tissue releases performed during their procedures. However, they would expect these releases to contribute to an increase in fatty infiltration of the musculature. Thus, it is possible the observed intensity readings for the direct anterior approach are higher than the authors would observe for individuals who had no intraoperative muscle releases. In addition, the authors did not assess the potential risks of the direct anterior approach detailed in the literature, such as superior gluteal or lateral cutaneous nerve compression or dissection injuries caused by retractors or rasps.22,23,27

As a result of the paucity of randomized, blinded studies examining the effect of surgical approach, this in vivo evaluation of the invasiveness of various approaches using MRI can provide insight into the benefits of minimally invasive surgery. The authors believe that MRI was able to demonstrate the effect of surgical approach on the muscle atrophy of the hip musculature in an objective and direct way. The results of this study may enable surgeons and patients to understand differences in surgical approach and interdisciplinary teams to refine their rehabilitation protocols to maximize postoperative muscle recovery.

Conclusion

The 3 surgical approaches resulted in postoperative differences in fatty atrophy of the musculature around the hip. Although the direct anterior approach resulted in less fatty atrophy as evidenced by MRI, all 3 surgical approaches resulted in equivalent clinical outcomes at 1 year.

References

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  27. Ince A, Kemper M, Waschke J, Hendrich C. Minimally invasive anterolateral approach to the hip: risk to the superior gluteal nerve. Acta Orthop. 2007;78(1):86–89. doi:10.1080/17453670610013466 [CrossRef] PMID:17453397

Patient Demographics at Baseline

CharacteristicDirect Anterior (n=9)Direct Lateral (n=9)Posterior (n=7)P
Age, mean±SD, y66.22±8.5363.67±6.7564.14±10.76.81
Sex, M:F, No.4:55:44:3.87
Height, mean±SD, cm173.67±10.97175.75±9.10172.96±9.90.85
Weight, mean±SD, kg82.50±20.9693.93±20.8687.93±25.48.58
BMI, mean±SD, kg/m227.02±4.3430.26±5.6828.90±5.86.46
Operative limb, R:L, No.4:55:43:4.87

Patient-Reported Outcomes at Baseline and 1 Year Postoperatively

OutcomeBaseline1 Year PostoperativelyChange
SF-12 MCS, mean±SD53.06±9.6256.37±7.952.04±9.59
SF-12 PCS, mean±SD31.37±8.4046.09±11.8215.48±9.44
WOMAC Pain, mean±SD44.57±19.8887.27±21.4243.44±21.12
WOMAC Stiffness, mean±SD39.13±21.7581.25±23.7043.33±29.88
WOMAC Function, mean±SD41.82±20.7186.36±22.5043.29±21.74
WOMAC Total, mean±SD43.42±17.5985.67±21.9043.64±19.46
HHS Pain, mean±SD20.58±7.9942.20±4.3520.50±7.19
HHS Function, mean±SD31.13±5.9144.20±4.7213.69±7.22
HHS Deformity4.004.000.00
HHS ROM, mean±SD2.21±1.444.40±1.431.87±2.31
HHS Total, mean±SD57.92±11.3890.29±22.2036.25±12.57

Muscle Intensity Readings by Surgical Approach

Muscle GroupSurgical Approach, Mean±SDP


Direct AnteriorDirect LateralPosteriorDA vs DLDA vs PosteriorDL vs Posterior
Gluteus maximus2549±7482888±5462655±965.636.158.666
Gluteus medius1612±5021958±4461606±253.000a.003a.000a
Gluteus minimus2127±7422637±7882208±378.001a.124.011a
Iliacus1221±4051826±7731375±259.000a.002a.003a
Obturator externus1363±6431692±5601603±575.014a.019a.008a
Obturator internus1470±6811750±5301569±526.320.600.023a
Pectineus1334±5681720±5571969±591.021a.010a.034a
Piriformis2105±10862055±3892169±1101.374.206.181
Psoas1189±3691479±5361381±282.008a.030a.033a
Quadratus femoris1254±5481530±4691339±403.016a.295.037a
Rectus femoris1786±4912128±4342266±553.167.448.849
Sartorius2540±9482660±7752496±1360.019a.017a.085
Tensor fascia lata2540±9483710±22562568±896.293.013a.407
Vastus intermedius1430±5381439±3201495±428.215.152.020a
Vastus lateralis1430±5091801±3831512±474.230.191.140

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct anterior approach group. Presented as mean ± standard deviation.

BaselineOne Year Post-OpChange
SF-12 MCS55.45 ± 11.5254.92 ± 9.421.49 ± 11.04
SF-12 PCS30.15 ± 8.5547.13 ± 10.8018.16 ± 9.67
WOMAC Pain44.44 ± 18.2885.63 ± 22.1147.86 ± 22.34
WOMAC Stiffness40.28 ± 24.0379.69 ± 24.9446.43 ± 32.54
WOMAC Function44.93 ± 20.3883.09 ± 20.6542.44 ± 23.28
WOMAC Total43.75 ± 15.7183.44 ± 21.7845.55 ± 18.92
HHS Pain19.00 ± 5.6841.75 ± 4.9523.43 ± 5.53
HHS Function29.90 ± 6.8744.50 ± 4.0714.14 ± 7.12
HHS Deformity4.00 ± 0.004.00 ± 0.000.00 ± 0.00
HHS ROM2.10 ± 1.454.38 ± 1.772.28 ± 2.05
HHS Total50.00 ± 18.5894.63 ± 8.9339.86 ± 10.63

Average Patient Reported Outcomes at baseline and one year post-operatively for the direct lateral approach group. Presented as mean ± standard deviation.

BaselineOne Year Post-OpChange
SF-12 MCS48.77 ± 7.9954.15 ± 8.711.85 ± 7.39
SF-12 PCS31.72 ± 7.7839.77 ± 14.598.11 ± 8.94
WOMAC Pain42.86 ± 20.8580.00 ± 26.9928.33 ± 22.48
WOMAC Stiffness41.07 ± 15.9775.00 ± 29.1233.33 ± 31.18
WOMAC Function43.91 ± 16.2580.46 ± 30.3831.86 ± 18.02
WOMAC Total42.87 ± 17.4279.12 ± 28.4230.69 ± 22.46
HHS Pain22.00 ± 11.0141.20 ± 5.6014.67 ± 10.50
HHS Function34.00 ± 4.6642.20 ± 5.568.67 ± 3.09
HHS Deformity4.00 ± 0.004.00 ± 0.000.00 ± 0.00
HHS ROM2.57 ± 1.294.60 ± 0.801.67 ± 1.70
HHS Total62.57 ± 15.5777.33 ± 33.6225.00 ± 14.45

Average Patient Reported Outcomes at baseline and one year post-operatively for the posterior approach group. Presented as mean ± standard deviation.

BaselineOne Year Post-OpChange
SF-12 MCS56.07 ± 8.9060.24 ± 1.572.77 ± 8.65
SF-12 PCS32.59 ± 8.6051.23 ± 4.6716.04 ± 7.26
WOMAC Pain46.43 ± 20.4896.43 ± 4.4045.83 ± 14.55
WOMAC Stiffness35.71 ± 23.5689.29 ± 10.4145.00 ± 23.18
WOMAC Function35.71 ± 23.5696.01 ± 5.4351.324 ± 17.90
WOMAC Total43.56 ± 19.6794.77 ± 5.0247.87 ± 15.29
HHS Pain21.43 ± 6.3943.43 ± 1.4020.00 ± 4.47
HHS Function30.00 ± 4.5745.29 ± 4.2015.67 ± 6.92
HHS Deformity4.00 ± 0.004.00 ± 0.000.00 ± 0.00
HHS ROM2.00 ± 1.514.29 ± 1.391.40 ± 2.80
HHS Total50.25 ± 20.0897.00 ± 6.9537.67 ± 10.24
Authors

The authors are from the Department of Surgery (EMV, JLH, BAL), Division of Orthopaedics, Schulich School of Medicine & Dentistry, Western University & London Health Sciences Centre, London; Robarts Research Institute (HAW), Western University, London; the Department of Surgery (SP), Division of Orthopaedics, Woodstock General Hospital, Woodstock; and the Department of Medical Imaging (JB), St Michael's Hospital, Toronto, Ontario, Canada.

Dr Vasarhelyi is a paid consultant for DePuy and Zimmer Biomet; has received grants from Physician Services Incorporated Foundation and DePuy; has received institutional support from DePuy, Stryker, and Smith & Nephew; and serves on the Data Safety Monitoring Board for Hip Innovation Technology. Mr Williams has received grants from Physician Services Incorporated Foundation. Dr Howard is a paid consultant for Stryker and Intellijoint; has received grants from DePuy; has received institutional research support from Stryker, DePuy, Smith & Nephew, Zimmer, and Microport; and holds stock in PersaFix Technologies. Dr Petis has received grants from Physician Services Incorporated Foundation. Dr Barfett has received grants from Physician Services Incorporated Foundation. Dr Lanting is a paid consultant for Intellijoint; has received grants from Physician Services Incorporated Foundation, Smith & Nephew, DePuy, and Stryker; and has received institutional support from Smith & Nephew, DePuy, and Stryker.

This study was supported by the London Health Sciences Centre Surgery Internal Research Fund (Grant titled: Direct Lateral, Anterior, and Posterior Approach: Imaging and Gait Analysis in Total Hip Arthroplasty) and the Physician Services Incorporated Foundation.

Correspondence should be addressed to: Edward M. Vasarhelyi, MD, MSc, Department of Surgery, Division of Orthopaedics, Schulich School of Medicine & Dentistry, Western University & London Health Sciences Centre, 339 Windermere Rd, London, Ontario, Canada N6A 5A5 (edward.vasarhelyi@lhsc.on.ca).

Received: May 08, 2019
Accepted: September 09, 2019
Posted Online: September 22, 2020

10.3928/01477447-20200910-01

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