Moderate strength evidence supports that obese patients with symptomatic osteoarthritis of the hip, when compared to non-obese patients, may achieve lower absolute outcome scores but a similar level of patient satisfaction and relative improvement in pain and function after total hip arthroplasty.

Rationale

There are four moderate quality studies that support the existence of lower clinical scores in obese patients with mild variation in the cutoff points that define obesity (Yeung et al; BMI>30, Stevens et al; BMI>30, Davis et al; BMI >35, Judge et al; BMI >30).  These results are supported by two low quality studies (McCalden et al; BMI>30, Jackson et al; BMI>30).  Similar improvements in clinical scores between obese and non-obese patients are supported by one moderate quality study (Judge et al) and two low quality studies (Bennett et al; BMI>40, McCalden et al). 

Similarities between obese and non-obese patient satisfaction with total hip replacement are supported by one moderate quality study (Yeung et al) and one low quality study (Villalobos et al; BMI>28). 

One moderate quality study identifies a higher incidence of post-operative dislocation and superficial wound infection in obese patients (Davis et al; BMI>35).  A low quality study reported a higher operative blood loss in obese patients (Bowditch et al; BMI>30). 

Most of the included studies used a BMI level >30 to define obesity and for use as a comparison with lower ranges.  This relatively low cutoff may mask some more dramatic differences in complications and outcomes at the higher levels, such as 40-50 and >50.  In addition, BMI may not be a specific enough index to define the proportionality and distribution of adipose tissue at surgical sites. 

  1. Aranda,Villalobos P.; Navarro-Espigares,J.L.; Hernandez-Torres,E.; Martinez-Montes,J.L.; Villalobos,M.; Arroyo-Morales,M. Body mass index as predictor of health-related quality-of-life changes after total hip arthroplasty: a cross-over study. J Arthroplasty; 2013/4: 4
  2. Bowditch,M.G.; Villar,R.N. Do obese patients bleed more? A prospective study of blood loss at total hip replacement. Ann R Coll Surg Engl.; 1999/5: 3
  3. Davis,A.M.; Wood,A.M.; Keenan,A.C.; Brenkel,I.J.; Ballantyne,J.A. Does body mass index affect clinical outcome post-operatively and at five years after primary unilateral total hip replacement performed for osteoarthritis? A multivariate analysis of prospective data. J Bone Joint Surg Br; 2011/9: 9
  4. Jackson,M.P.; Sexton,S.A.; Yeung,E.; Walter,W.L.; Walter,W.K.; Zicat,B.A. The effect of obesity on the mid-term survival and clinical outcome of cementless total hip replacement. J Bone Joint Surg Br; 2009/10: 10
  5. Judge,A.; Cooper,C.; Arden,N.K.; Williams,S.; Hobbs,N.; Dixon,D.; Gunther,K.P.; Dreinhoefer,K.; Dieppe,P.A. Pre-operative expectation predicts 12-month post-operative outcome among patients undergoing primary total hip replacement in European orthopaedic centres. Osteoarthritis Cartilage; 2011/6: 6
  6. McCalden,R.W.; Charron,K.D.; MacDonald,S.J.; Bourne,R.B.; Naudie,D.D. Does morbid obesity affect the outcome of total hip replacement?: an analysis of 3290 THRs. J Bone Joint Surg Br; 2011/3: 3
  7. Stevens,M.; Paans,N.; Wagenmakers,R.; van,Beveren J.; van Raay,J.J.; van der Meer,K.; Stewart,R.; Bulstra,S.K.; Reininga,I.H.; van,den Akker-Scheek,I The influence of overweight/obesity on patient-perceived physical functioning and health-related quality of life after primary total hip arthroplasty. Obes.Surg; 2012/4: 4
  8. Yeung,E.; Jackson,M.; Sexton,S.; Walter,W.; Zicat,B.; Walter,W. The effect of obesity on the outcome of hip and knee arthroplasty. Int Orthop; 2011/6: 6
  9. Bennett,D.; Gibson,D.; O'Brien,S.; Beverland,D.E. Hip arthroplasty in morbidly obese patients - Intra-operative and short term outcomes. HIP International; 2010/1: 1