title: The effect of intrinsic loading and reconstruction upon grip capacity and finger extension kinematics.
abstract: OBJECTIVE
  To compare active and passive reconstructive procedures for tetraplegia and their ability to produce a powerful grip and allow appropriate finger extension in a cadaveric model.
  
  
  METHODS
  Seventeen fresh-frozen hands were used, which included 5 in intrinsic minus and intrinsic activation conditions, 6 with Zancolli-lasso tenodeses, and 6 with modified House tenodeses to simulate intrinsic function. To test grip, flexor digitorum profundus tendons were powered with a motor. Polyvinyl chloride cylinders of diameters 43, 51, 57, 70, or 89 mm and masses 250, 400, or 550 g were used. Grip was considered successful if the cylinder was grasped and resisted gravity. Finger extension was tested by powering the extensor tendons in the same hands.
  
  
  RESULTS
  No successful grasps were recorded in the intrinsic minus hands for larger diameter cylinders (≥ 70 mm), whereas multiple successes were seen after intrinsic activation and after Zancolli-lasso and House procedures. Whereas active intrinsic and the House reconstruction reached near full extension, this was not true for the Zancolli-lasso group.
  
  
  CONCLUSIONS
  These data demonstrated that active and passive intrinsic reconstruction methods improved basic grasp and release kinematics in experimental cadaver hand models. Using our model and based on the more optimal kinematics and full extension of the House procedure, we suggest that this should be the preferred tenodesis-based intrinsic reconstruction method. Nevertheless, both procedures were equally successful at grasping objects of the sizes and masses studied.
  
  
  CONCLUSIONS
  Comparative clinical studies are indicated to corroborate the findings of this cadaveric hand model.
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Diego, CA; Department of Veterans Affairs, San Diego, CA; Swiss Paraplegic Research, and the Swiss Paraplegic Centre, Nottwil, Switzerland; Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: David A
authors.initials: DA
authors.lastname: Muzykewicz
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Diego, CA; Department of Veterans Affairs, San Diego, CA; Swiss Paraplegic Research, and the Swiss Paraplegic Centre, Nottwil, Switzerland; Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Ursina
authors.initials: U
authors.lastname: Arnet
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Diego, CA; Department of Veterans Affairs, San Diego, CA; Swiss Paraplegic Research, and the Swiss Paraplegic Centre, Nottwil, Switzerland; Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Fridén
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Diego, CA; Department of Veterans Affairs, San Diego, CA; Swiss Paraplegic Research, and the Swiss Paraplegic Centre, Nottwil, Switzerland; Sahlgrenska University Hospital, Gothenburg, Sweden. Electronic address: rlieber@ucsd.edu.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lieber
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D005385:Fingers / Q000503:physiopathology*; D006225:Hand / Q000503:physiopathology / Q000601:surgery; D006227:Hand Deformities, Acquired / Q000503:physiopathology / Q000601:surgery*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011782:Quadriplegia / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000150:complications* / Q000503:physiopathology / Q000601:surgery; D053656:Tenodesis / Q000379:methods*
keywords: House procedure; Zancolli-lasso procedure; intrinsic balancing; reconstructive hand surgery; tetraplegia