RR-PO-1917

Wednesday 10:00, Palau de Congressos, Exhibition Hall  [Display No. 495]

WOMEN AWAITING TOTAL KNEE ARTHROPLASTY HAVE GREATER PHYSICAL IMPAIRMENT AND LOWER INSULIN LIKE GROWTH FACTOR - I  VALUES THAN DO MALES. Pagura, S., Thomas, S., Ezzat, S., Kennedy, D., and Woodhouse L. Orthopaedic and Arthritic Institute and the University of Toronto. Toronto. Canada PURPOSE:  Women experience greater functional impairment and occurrence of osteoarthritis (OA) than men.  We hypothesize that lower levels of Insulin-like Growth Factor-I (IGF-I) may contribute to gender differences in physical impairments associated with end-stage OA. RELEVANCE: Understanding factors that contribute to OA may result in alternative methods of management. SUBJECTS: A cross-sectional comparison was conducted on Total Knee Arthroplasty (TKA) candidates (n=25 men; n = 33 women) and healthy controls (CONT)(n = 25 men; n = 56 women) of similar age (55 to 75 years). METHODS AND MATERIALS: All participants underwent testing for Physical function, Perceived Physical Function and Serum IGF-I.  Physical function was characterized with self paced walk (SPW), stair performance and Timed Up and Go (TUG) tests and Perceived Physical Function was characterized utilizing the Lower Extremity Activity Profile (LEAP) and the Western Ontario and McMaster Osteoarthritis Index (WOMAC).  Serum IGF-I samples were batch analyzed to reduce variation and levels were determined using radio-immunoassay. ANALYSES:  Comparisons across group and gender were made using a general linear model ANOVA (p < 0.05)using the statistical package SAS. RESULTS: Serum IGF-I values were markedly reduced in women (p=0.0002) and TKA women had significantly (p=0.03) reduced levels relative to their controls.  Lean body mass correction did not alter findings in serum levels. Estrogen, also a known contributer to IGF-I levels did not play any role in the disparity found between female CONT and TKA.  Values consistent with clinical IGF-I deficiency were observed in 21% of TKA women and 4% of TKA men. SPW revealed significant group and gender differences (p=0.001) with women demonstrating greater functional impairment walking 36% slower than their healthy counterparts. Other functional measures revealed similar findings with women requiring 86% longer to complete the TUG and 67% longer to complete one flight of stairs. Although still impaired, male TKA performed better in the functional tests with deficits ranging from 21-35 %. Aggregate WOMAC scores did not differ between TKA men (115.2 + 20.4) and women (122.7 + 23.8), although, as expected, there was significantly more disability than observed in healthy controls. Conclusions: Our findings indicate that physical function and not perceived physical function is more impaired in women awaiting TKA than their male counterparts.  Serum IGF-I levels are also more markedly reduced in women than men.  The gender differences observed biochemically and with functional performance suggest, that the pathophysiology of end stage OA may differ between men and women and treatment options may need to be further explored.