title: An Algorithmic, Pie-Crusting Medial Soft Tissue Release Reduces the Need for Constrained Inserts Patients With Severe Varus Deformity Undergoing Total Knee Arthroplasty.
abstract: We studied the need to use a constrained insert for residual intraoperative instability and the 1-year result of patients undergoing total knee arthroplasty (TKA) for a varus deformity. In a control group, a "classic" subperiosteal release of the medial soft tissue sleeve was performed as popularized by pioneers of TKA. In the study group, an algorithmic approach that selectively releases and pie-crusts posteromedial structures in extension and anteromedial structures in flexion was used.
  
  
  
  All surgeries were performed by a single surgeon using measured resection technique, and posterior-stabilized, cemented implants. There were 228 TKAs in the control group and 188 in the study group. Outcome variables included the use of a constrained insert, and the Knee Society Score at 6 weeks, 4 months, and 1 year postoperatively. The effect of the release technique on use of constrained inserts and clinical outcomes were analyzed in a multivariate model controlling for age, sex, body mass index, and severity of deformity.
  
  
  
  The use of constrained inserts was significantly lower in study than in control patients (8% vs 18%; P = .002). There was no difference in the Knee Society Score and range of motion between the groups at last follow-up. No patient developed postoperative medial instability.
  
  
  
  This algorithmic, pie-crusting release technique resulted in a significant reduction in the use of constrained inserts with no detrimental effects in clinical results, joint function, and stability. As constrained TKA implants are more costly than nonconstrained ones, if the adopted technique proves to be safe in the long term, it may cause a positive shift in value for hospitals and cost savings in the health care system.
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Goudarz Mehdikhani
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Morales Moreno
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Reid
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Ana
authors.initials: A
authors.lastname: de Paz Nieves
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Yuo-Yu
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.
authors.forename: Alejandro
authors.initials: A
authors.lastname: González Della Valle
mesh_terms: D000368:Aged; D000465:Algorithms; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D015992:Body Mass Index; D017046:Cost Savings; D005260:Female; D006801:Humans; D007717:Knee / Q000002:abnormalities* / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009068:Movement; D009985:Orthopedics / Q000379:methods / Q000592:standards*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010329:Patella / Q000601:surgery; D011184:Postoperative Period; D016059:Range of Motion, Articular; D012044:Regression Analysis; D012189:Retrospective Studies; D066231:Surgeons; D016896:Treatment Outcome
keywords: constrained insert; pie crusting; results; total knee arthroplasty; varus deformity