title: The management of extensor mechanism complications in total knee arthroplasty. AAOS exhibit selection.
abstract: Complications involving the knee extensor mechanism and patellofemoral joint occur in 1% to 12% of patients following total knee arthroplasty and have major negative effects on patient outcomes and satisfaction. The surgeon must be aware of intraoperative, postoperative, and patient-related factors that can increase the rate of these problems. This review focuses on six of the most commonly encountered problems: patellar tendon disruption, quadriceps tendon rupture, patellar crepitus and soft-tissue impingement, periprosthetic patellar fracture, patellofemoral instability, and osteonecrosis of the patella. The goals of this report are to (1) review the relevant anatomy of the knee extensor mechanism, (2) present risk factors that may lead to extensor mechanism complications, (3) provide a diagnostic and treatment algorithm for each of the aforementioned problems, and (4) review the specific surgical techniques of Achilles tendon allograft reconstruction and synthetic mesh augmentation. Extensor mechanism disorders following total knee arthroplasty remain difficult to manage effectively. Although various surgical techniques have been used, the results in patients with a prior total knee arthroplasty are inferior to the results in the young adult without such a prior procedure. Surgical attempts at restoration of the knee extensor mechanism are usually warranted; however, the outcomes of treatment of these complications are often poor, and management of patient expectations is important.
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, Barnes Jewish Hospital, 660 South Euclid Avenue, Campus Box 8233, St. Louis, MO 63110. E-mail address: namd@wudosis.wustl.edu.
authors.forename: Denis
authors.initials: D
authors.lastname: Nam
authors.affiliation: Division of Adult Reconstruction, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street S.W., Rochester, MN 55905.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Abdel
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Cross
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: LaMont
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: Keith R
authors.initials: KR
authors.lastname: Reinhardt
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: McArthur
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: David J
authors.initials: DJ
authors.lastname: Mayman
authors.affiliation: Division of Adult Reconstruction, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street S.W., Rochester, MN 55905.
authors.forename: Arlen D
authors.initials: AD
authors.lastname: Hanssen
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Sculco
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods / Q000534:rehabilitation; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D010329:Patella / Q000601:surgery*; D017847:Patellar Ligament / Q000601:surgery; D057071:Patellofemoral Joint / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis / Q000628:therapy*; D011475:Prosthesis Failure; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000009:adverse effects* / Q000379:methods / Q000534:rehabilitation