title: Soft tissue restricts impingement-free mobility in total hip arthroplasty.
abstract: Impingement is a major source for decreased range of motion (ROM) and dislocation in total hip arthroplasty (THA). In the current study we analyzed the impact of soft tissue impingement on ROM compared to bony and/or prosthetic impingement.
  
  
  
  In the course of a prospective clinical trial 54 patients underwent cementless total hip arthroplasty in the lateral decubitus position using imageless navigation. The navigation device enabled intra-operative ROM measurements indicating soft tissue impingement. Post-operatively, all patients received postoperative 3D-CT. Absolute ROM without bony and/or prosthetic impingement was calculated with the help of a collision-detection-algorithm.
  
  
  
  Due to soft tissue impingement we found a reduced ROM of over 20° (p < 0.001) compared to bony and/or prosthetic impingement regarding flexion, extension, abduction and adduction and of over 10° regarding external rotation (p < 0.001). In contrast, soft tissue impingement showed less impact on internal rotation in 90° of flexion (p = 0.76). Multivariate analysis showed an association between BMI and flexion, whereas all other ROM directions were independent of BMI.
  
  
  
  Soft tissue has a major impact on impingement-free ROM after THA. For the majority of movements, soft tissue restrictions are more important than bony and prosthetic impingement. Future models of patient individual joint replacement including pre-operative (CT) planning and intra-operative navigation should include algorithms additionally accounting for soft tissue impingement.
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany. m.woerner@asklepios.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Woerner
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Weber
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Sendtner
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Springorum
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Worlicek
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Craiovan
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077, Bad Abbach, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Renkawitz
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D015207:Osteoarthritis, Hip / Q000601:surgery*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*
keywords: Impingement; Minimally invasive; Navigation; ROM; Soft Tissue; Total hip arthroplasty