title: Feasibility of using ultrasonic emission for clinical evaluation of prosthetic hips.
abstract: BACKGROUND
  Previous acoustic emission (AE) studies of the hip have proposed using AE for the diagnosis of musculoskeletal conditions and assessing the clinical status (loosening, wear, etc.) of prostheses. However, these investigations have had problems with spurious signal noises or complicated measurement techniques, or both.
  
  
  OBJECTIVE
  We performed a study on 98 patients to evaluate the feasibility of employing ultrasonic emission (UE) to determine total hip arthroplasty (THA) status, using a simple, hand-held measurement system that has addressed some of the prior problems with hip AE studies.
  
  
  METHODS
  UE was recorded from both hips of study patients during walking and sitting activities. The patients had 79 metal-on-polyethylene implants, and at least 15 each with ceramic-on-polyethylene, ceramic-on-ceramic and metal-on-metal articulations; 10 young subjects without THA were similarly recorded as controls. Data were obtained from waveform analysis and standard UE signal parameters. Patient radiographs were evaluated for THA status, and wear measurements were made for metal-on-polyethylene articulations.
  
  
  RESULTS
  There were distinct types of UE waveforms produced; one was typical of the control subjects as well as some patients. We did not find an apparent relationship among these waveform types and type of THA bearing, length of implantation or wear measurements in the metal on polyethylene bearings.
  
  
  CONCLUSIONS
  Our results suggest that it may be possible to assess the status of THA by UE signals, but further studies are necessary to quantify this finding. The clinical relevance of this investigation is that a simple, in-office screening means for THA patients could indicate those patients who require closer follow-up and monitoring.
authors.affiliation: New York University School of Medicine, Musculoskeletal Research Center, NYU Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003, USA. fkummer@yahoo.com
authors.forename: Frederick
authors.initials: F
authors.lastname: Kummer
authors.forename: William L
authors.initials: WL
authors.lastname: Jaffe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D002516:Ceramics; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D009519:New York City; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D016896:Treatment Outcome; D014465:Ultrasonics / Q000295:instrumentation; D016138:Walking
chemical_list: D008670:Metals; D020959:Polyethylene