title: Arthrofibrosis following total knee replacement; does therapeutic warfarin make a difference?
abstract: Arthrofibrosis following total knee replacement (TKR) is a relatively common complication which results in a reduction in knee range of movement and patient dissatisfaction. A retrospective study examined the relationship between anticoagulation with therapeutic warfarin and rates of arthrofibrosis following TKR. Arthrofibrosis was defined as less than 80 degrees of knee flexion 6-8 weeks post-TKR. Patients were warfarinised if they had a history of thrombophilic tendencies or medical conditions necessitating anti-coagulation, rather than as routine thromboprophylaxis. All other patients received thromboprophylaxis using low molecular weight heparin. A total of 728 patients underwent 874 primary TKR between 1993 and 2002 in one centre, performed by four surgeons. Mean age was 68 years (range 48-89 years) and there were 483 female and 391 male knees. Eighty cases were warfarinised post-operatively (53 female, 27 male). Overall, 83 of 874 TKRs (9%) had arthrofibrosis (57 female, 26 male) requiring manipulation under anaesthetic (MUA). In the warfarinised group, 21 knees (26%) had an MUA (15 female, 6 male). This compared to 62 cases (8%) requiring MUA in the non-warfarinised group (42 female, 20 male). There was a statistically significant difference on Fisher's exact testing (P<0.0001) between groups. Following MUA, knee flexion improved in 95% cases to a minimum 95 degrees but 8 cases had a fixed flexion deformity of 5-10 degrees . In conclusion, therapeutic warfarinisation post-TKR leads to a statistically greater chance of the patient developing arthrofibrosis compared to prophylactic low molecular weight heparin and that patients should be counseled appropriately.
authors.affiliation: Wakefield Orthopaedic Clinic, 270 Wakefield St., Adelaide, SA 5000, Australia. neil@nwalton22.fsnet.co.uk
authors.forename: N P
authors.initials: NP
authors.lastname: Walton
authors.forename: I
authors.initials: I
authors.lastname: Jahromi
authors.forename: P J
authors.initials: PJ
authors.lastname: Dobson
authors.forename: K R
authors.initials: KR
authors.lastname: Angel
authors.forename: P L
authors.initials: PL
authors.lastname: Lewis
authors.forename: D G
authors.initials: DG
authors.lastname: Campbell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D005355:Fibrosis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use; D006801:Humans; D007592:Joint Diseases / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D026201:Musculoskeletal Manipulations; D018583:Pliability; D011183:Postoperative Complications / Q000473:pathology / Q000517:prevention & control*; D012189:Retrospective Studies; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D014859:Warfarin