title: Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty.
abstract: OBJECTIVE
  We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches.
  
  
  METHODS
  In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated.
  
  
  RESULTS
  The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon.
  
  
  CONCLUSIONS
  The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42.
authors.affiliation: Stanford University, 450 Broadway St, Redwood City, CA 94063-6342, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Amanatullah
authors.affiliation: Ann Arbor Bone and Joint Surgery, St. Joseph Mercy Ann Arbor Hospital, 5315 Elliott DR., Suite 304, Ypsilanti, MI 48197, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Masini
authors.affiliation: Institute of Clinical Orthopedics and Neuroscience, Desert Regional Medical Center, 1180 N. Indian Canyon, Suite W-201, Palm Springs, CA 92262, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Roger
authors.affiliation: Mayo Clinic, 200 First Street SW, Rochester MN, 55905, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Pagnano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D002102:Cadaver; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000293:injuries*; D011897:Random Allocation; D013708:Tendon Injuries / Q000209:etiology
keywords: Direct anterior approach; Direct superior approach; Inadvertent muscle damage; Total hip arthroplasty