A new technique for determining proper mechanical axis alignment during total knee arthroplasty

Progress toward computer-assisted TKA

K. A. Krackow, L. Serpe, M. J. Phillips, M. Bayers-Thering, William Mihalko

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

Successful total knee arthroplasty (TKA) relies on proper positioning of prosthetic components to restore the mechanical axis of the lower extremity. This report presents and analyzes a new noninvasive method using the Optotrack (Northern Digital Inc, Ontario, Canada) to accurately determine the center of the femoral head. This method, together with direct digitization of the bony landmarks of the knee and ankle intraoperatively, permits placement of the lower extremity in proper alignment intraoperatively. It also permits the surgeon to follow all the angles of movement or rotation and all displacements that occur at each step of the operative procedure. The Optotrack is an infrared tracking system that has been modified to be mounted on the distal femur and proximal tibia to record the motion and alignment of the knee intraoperatively via a customized Windows-based program. In addition to presenting our first case, which, importantly, represents the first computer-assisted TKA in a patient, we report on the accuracy and reproducibility of the technique for locating the center of the femoral head obtained during an extensive series of cadaver studies. Location of the femoral head, a major aspect of effecting neutral mechanical axis alignment, appears to be possible to within 2-4 mm, which corresponds to an angular accuracy of better than 1°. This method requires no computed tomography scans or other preliminary marker placement. The only basic requirement other than the instrumentation described is a freely mobile hip, which is generally present in TKA patients.

Original languageEnglish (US)
Pages (from-to)698-702
Number of pages5
JournalOrthopedics
Volume22
Issue number7
StatePublished - Aug 2 1999
Externally publishedYes

Fingerprint

Knee Replacement Arthroplasties
Thigh
Lower Extremity
Knee
Operative Surgical Procedures
Ontario
Tibia
Cadaver
Ankle
Femur
Canada
Hip
Tomography

All Science Journal Classification (ASJC) codes

  • Orthopedics and Sports Medicine
  • Surgery

Cite this

A new technique for determining proper mechanical axis alignment during total knee arthroplasty : Progress toward computer-assisted TKA. / Krackow, K. A.; Serpe, L.; Phillips, M. J.; Bayers-Thering, M.; Mihalko, William.

In: Orthopedics, Vol. 22, No. 7, 02.08.1999, p. 698-702.

Research output: Contribution to journalArticle

Krackow, K. A. ; Serpe, L. ; Phillips, M. J. ; Bayers-Thering, M. ; Mihalko, William. / A new technique for determining proper mechanical axis alignment during total knee arthroplasty : Progress toward computer-assisted TKA. In: Orthopedics. 1999 ; Vol. 22, No. 7. pp. 698-702.
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