title: Lessons learned from selective soft-tissue release for gap balancing in primary total knee arthroplasty: an analysis of 1216 consecutive total knee arthroplasties: AAOS exhibit selection.
abstract: BACKGROUND
  Soft-tissue releases are commonly necessary to achieve symmetrical flexion and extension gaps in primary total knee arthroplasty performed with a measured resection technique. We reviewed the frequency of required releases according to preoperative alignment and the clinical and radiographic results; associations with failure, reoperations, and complications are presented.
  
  
  METHODS
  We reviewed 1216 knees that underwent primary total knee arthroplasty from 2004 to 2009; 774 (64%) were in female patients and 442 (36%), in male patients. In the coronal plane, 855 knees had preoperative varus deformity, 123 were neutral, and 238 had valgus deformity. The mean age at the time of the index procedure was 62.7 years (range, twenty-three to ninety-four years), and the mean body mass index was 32.7 kg/m² (range, 17.4 to 87.9 kg/m²). Clinical outcomes included the Knee Society Score (KSS), implant failure, reoperation, and complications. Radiographs were analyzed for component alignment.
  
  
  RESULTS
  The only difference in the total KSS was found at the time of final follow-up between valgus knees with zero releases (total KSS = 178) and those with one or two releases (KSS = 160, p = 0.026). Overall, 407 knees (33.5%) required zero releases, 686 (56.4%) required one or two releases, and 123 (10.1%) required three or more releases. Among varus knees, 37% required zero releases, 55% required one or two releases, and 7.5% required three or more releases. Among neutral knees, 39% required zero releases, 55% required one or two releases, and 5.7% required three or more releases. Only 17% of valgus knees required zero releases whereas 61% required one or two releases and 21.8% required three or more releases. Valgus knees required more releases than neutral or varus knees did (p < 0.001).
  
  
  CONCLUSIONS
  Selective soft-tissue release for gap balancing in primary total knee arthroplasty is an effective technique that produced excellent clinical and radiographic results regardless of preoperative alignment. Consistent anatomic coronal-plane alignment and soft-tissue balance could be achieved without bone cut modification by using measured bone resection and selective soft-tissue release.
authors.affiliation: University of Utah Orthopaedic Center, 590 Wakara Way, Salt Lake City, UT 84108.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Peters
authors.forename: Chris
authors.initials: C
authors.lastname: Jimenez
authors.forename: Jill
authors.initials: J
authors.lastname: Erickson
authors.forename: Mike B
authors.initials: MB
authors.lastname: Anderson
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Pelt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D017885:Collateral Ligaments / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010020:Osteonecrosis / Q000601:surgery*; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D011475:Prosthesis Failure; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome