The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve

Summary

The anterior-based muscle-sparing approach for total hip arthroplasty (THA) is associated with a learning curve. However, the improved clinical outcome in the early post-operative phase makes the consideration to transition worthwhile.

Abstract

Surgeons considering transitioning to an anterior-based approach for THA are concerned about the learning curve and the reported marginal clinical benefit. Accordingly, the first cohort of THAs, which were implanted by a single surgeon using the anterior-based muscle-sparing approach (ABMS), was analyzed. The goal of the study was to test 1) whether patient-reported outcomes improved and 2) whether the complication rate decreased with the number of THAs performed. A retrospective cohort study on the first 30 primary THA cases (27 patients) of one surgeon (January 2021-April 2021) using the ABMS approach was conducted. These 30 THAs were compared to 30 primary THA cases (30 patients) done immediately prior to the transition by the same surgeon (September 2020-December 2020) using the posterior approach (PA). The Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score (HOOS Junior), and Forgotten Joint Score (FJS) obtained 6 weeks and 6 months after surgery were compared. In addition, three consecutive groups based on equal numbers of THAs were compared for the incidence of complications and surgery time. At 6 weeks after THA, the OHS was 6 points higher after the ABMS approach (p = 0.0408), and the OHS was comparable at 6 months. The HOOS Junior and FJS were similar at 6 weeks and 6 months after surgery. In the first 10 THAs using the ABMS approach, one patient had a greater trochanter fracture, and one patient had an intraoperative proximal femur fracture. No further immediate interoperative or postoperative complications occurred. Surgery time significantly reduced with the number of THAs performed. Transitioning from the PA to the ABMS approach is associated with a learning curve, which is limited to the first 20 cases. The effect of improved clinical outcomes is apparent within the early postoperative period. After 6 months, THA patients do well regardless of the approach.

Introduction

In total hip arthroplasty (THA), the surgical approach serves to visualize the acetabulum and proximal femur and to prepare the acetabulum and proximal femur for safe and stable implantation of the prosthetic components¹. An ideal surgical approach in THA provides adequate exposure while minimizing the risk of damage to the muscles, blood vessels, and nerves and the risk of postoperative instability.

The anterior-based muscle-sparing (ABMS) approach in THA utilizes the muscle interval popularized by Sir Reginald Watson-Jones in 1930². The ABMS approach avails itself of the intermuscular plane ....

Protocol

An institutional review board approved this retrospective study (IRB 00060819) of deidentified prospectively collected data.The protocol followed the guidelines approved by the human institutional review board of Adventist Health Lodi Memorial. A written informed consent was obtained from the patients before the procedure.

NOTE: As a representative patient, the clinical course of a 78-year-old male with left hip pain is described. His symptoms included a 2 year history of left groin pain aggravated by activity, night pain not adequately relieved by anti-inflammatory medication, and limitations of daily activities. The Oxford Hip Score at hi....

Results

At 6 weeks after THA, the mean OHS was 35 points after the ABMS approach and 29 after the PA (p = 0.0408). The HOOS and FJS did not differ significantly 6 weeks after THA between the ABMS approach and PA. At 6 months after THA, no differences in outcome scores were observed (Table 1).

In the first 10 THAs using the ABMS approach, one patient had a greater trochanter fracture treated with a tension band suture, and one patient had an intraoperative proximal femur fracture treat.......

Discussion

Minimally invasive surgery (MIS) has gained interest in all fields of surgery due to the faster recovery, lower blood loss, and improved perioperative pain control. THA has adopted MIS to increase hip stability and enhance post-operative mobilization. The ABMS approach utilizes the muscle interval between the tensor fasciae latae and the gluteus medius muscles but without incising or detaching the muscles and tendons. A surgeon considering transitioning to the ABMS approach would be well advised to attend a cadaver cours.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
30° Offset Masterloc Broach handle L	Medacta	01.10.10.461
30° Offset Masterloc Broach Handle R	Medacta	01.10.10.460
3D Printed Acetabular Component	Medacta	01.38.058DH
ACE Wrap 6 in		140700
Acetabular Liner	Medacta	01.32.4048HCT
AMIS 2.0 Genera Tray	Medacta	01.15.10.0294	Curved cup impactor
AMIS 2.0 General Tray	Medacta	01.15.10.0293	Screw driver for cup impactor
Anterior Auxillery	Medacta	ALAUX
Biolox Ceramic Head	Medacta	01.29.214
Chloraprep 26 mL	BD	301185
Drape Mayostand	Cardianal	7999
Ethibond Size 5	Ethicon	103831
Femoral Neck Elevator		3006
Femoral neck elevator		01.15.10.0037
Ioban	3M	15808
Ketorolac 30 mg/mL	SN	MED00575
Masterloc Inst (MLOCINS)	Medacta	01.39S.301US
Masterlock Femoral Stem	Medacta	01.39.408
Mpact General (MPACT)	Medacta	01.32S.300US
Mpact Liner Trial face changing/offset	Medacta	01.325.305
Mpact Liner Trial face changing/offset	Medacta	01.325.305
Mpact liner trial flat/hooded	Medacta	01.32S.301
Mpact liner trial flat/hooded	Medacta	01.32S.301
Mpact Reamers (MPACT)	Medacta	01.32S.101US	Regular hemi reamers swapped out for Half-Moon Reamers
Single Prong Acetabular Retractor, Extra Deep		6570-01
Single Prong Acetabular Retractor, Standard		6570
Single Prong Broad Acetabular Retractor		6320
Stapler Kine Proximate Plus 35 W	Ethicon	52686
Tranexamic acid 1 g	SN	MED01071
Unger Narrow Hohmann		3002
Vicryl 1 CTX	Ethicon	143836
Vicryl 2-0 CT2	Ethicon	9174