Hip Replacement Surgery

Obesity and its effects on hip replacement surgery

Obesity is a major contributing factor to those diseases that require total hip replacement surgery, such as osteoarthritis. Much discussion exists about whether hip replacement surgery should be withheld from obese patients, (1) as not only does obesity increase the likelihood of an early onset of the need for hip replacement surgery (2) but there is also an increased risk of the development of post-operative complications. (3) (4)

Obesity is defined as excessive weight or fat accumulation in the body that has an adverse affect on health, according to the World Health Organization (WHO). Obesity can be measured by using (5) the Body Mass Index (BMI) which is defined as the ratio of body-weight to height. Obesity, according to BMI is defined as an score of over 30 kg/m2. (6)

Obesity and the prevalence of hip replacement surgery

Obesity increases the risks of developing a need for total hip replacement surgery, as it is one of the major contributing factors to osteoarthritis. (7) Osteoarthritis or degenerative joint disease (DJD) is a progressive disorder of the joints. It is caused by the gradual loss of cartilage, while bony spurs (osteophytes or bony growths on normal bones) (8) and cysts (fluid containing lesions on the bone) (9) develop at the intersection of the joints. (10) In a study conducted on 568 women who underwent total hip replacement therapy due to osteoarthritis, it was reported that a higher body mass index score was associated with an increased risk in the need for hip replacement surgery. (P for trend = 0.0001). (11) A higher body mass index, results in larger body weight pushing down on the joints, causing stronger friction between two adjoining bones, wearing them down faster. (12)

According to a further study, there is a significant correlation between a larger BMI score and the need for total hip replacement surgery. In 840 hip replacement surgeries done between 1992 and 2002 they found that in males the highest operation numbers occurred within the BMI range of severely obese (37.5 to 39.9 kg/ m2). In females they found that the highest prevalence for the need to operate was in the group registering more than 40 kg/m2 on the BMI scale. They found no significant correlation between obesity and the risk of revision procedures. (13)

Research conducted on 204 patients who underwent total knee or total hip replacement surgery between January 2002 and December 2004 showed that of these patients 48% had total hip replacement surgery. Obesity was found to be significantly related with the need for such surgery. 72% (146 patients) of the statistical sample were obese (BMI = equal to or more than 30 kg/m2) and 21% (42 patients) were overweight (25 kg/m2 to less than 30 kg/m2). In the obese group it was reported that there is a correlation between obesity and the need for total hip replacement, not just in the elderly, but in younger patients as well. (2) According more research, morbidly obese patients can have an onset of the need for total hip replacement surgery up to 10 years earlier than those in the normal body weight BMI range. (14)

Obesity and post-operative complications

If obesity is a major contributing factor in the need for total hip replacement surgery, why then is there discussion about not allowing the surgery for the overweight or obese? Many studies have been conducted on how obesity affects not only post-operative recovery time but also the need for revision procedures, thus the effectiveness of the surgery.

The continued debate is centered mostly on the cost of surgery and postoperative recovery in obese patients as opposed to non-obese patients.  1300 patients in two community hospitals were studied and the research found that operation time was not affected by a higher BMI score, but extremely obese patients were 2.3 times more likely to stay in hospital for more than 5 days post operation than those in lower BMI score categories. Patients with a BMI score of over 25 kg/m2 had significantly poorer Harris hip scores. (15) The Harris hip score test was developed by the prominent orthopedist William Harris, and is used to assess hip function and the effectiveness of hip replacement surgery. (16)

Post operative recovery time is defined as how quickly the body is able to heal, or return to normality and wholeness. (17) Obesity complicates the healing process. Bowditch and Villar (18) report that obese patients bled significantly more during and after total hip replacement surgery (P < 0.0001) than those in the optimal BMI weight range. Blood loss is a major complication of surgery, and can seriously hinder postoperative recovery.

Increased blood loss during surgery was found to lead to a higher risk of the operative or post-operative complication of deep vein thrombosis. (19) Deep vein thrombosis is the formulation of a blood clot in the veins, most commonly in the leg veins. Obesity is amongst the leading risk factors for the development of DVT, though there is much debate on this issue, as obesity may not be a contributing fact on its own, more the immobility associated with obesity. (20) (21)

McLaughlin et al. report that 260 patients who underwent hip replacement surgery were examined over a 10 to 18 year period to determine the long term effects of surgery, specifically on the obese as opposed to the non-obese. No significant correlation was found between obesity and an increased recovery time, though in the obese groups there were 7 patients with pre-operative complications. (22)

Obesity and hip replacement.

Obesity increases the likelihood that total hip replacement will not just be needed, but this need will occur at a younger age. Obesity also increases complications not just during surgery but in the post-operative recovery phase. Continued obesity could also increase the chances for the need of a revision operation.

Losing the weight is advisable for the prevention of the early onset for the need of total hip replacement, for reducing the risk of operative and postoperative complications, and in reducing the time spent in hospital, thus the cost of the recovery.

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(1) Turgeon TR, Santore RF, Coutts RD. Influence of obesity on outcome following primary hip replacement surgery. American Academy of Orthopaedic Surgeons meeting; March 22-24, 2006; Chicago, IL. Paper 010. Retrieved July 8th, 2011, http://www.medscape.com/viewarticle/538540

(2) Excess Weight Predicts Younger Age at Hip and Knee Replacement, Peter Janiszewski, April 12, 2010. Retrieved July 8th, 2011, http://scienceblogs.com/obesitypanacea/2010/04/excess_weight_predicts_younger.php

(3) Ishak, M. A. and Morley, K. D. (1981), Deep venous thrombosis after total hip arthroplasty: A prospective controlled study to determine the prophylactic effect of graded pressure stockings. British Journal of Surgery, 68: 429–432. Retrieved July 8th, 2011, www.ncbi.nlm.nih.gov/pubmed/7016245

(4) J. R. McLaughlin, MD, Director1; and K. R. Lee, MD, Clinical Associate Professor. The outcome of total hip replacement in obese and non-obese patients at 10- to 18-years. Journal of Bone and Joint Surgery - British Volume, Vol 88-B, Issue 10, 1286-1292. Retrieved July 8th, 2011, web.jbjs.org.uk/cgi/content/short/88-B/10/1286

(5) Obesity and overweight, Fact sheet N°311, March 2011. Retrieved July 8th, 2011, http://www.who.int/mediacentre/factsheets/fs311/en/index.html

(6) Obesity, Wikipedia. Retrieved July 8th, 2011, http://en.wikipedia.org/wiki/Obesity

(7) Elizabeth W Karlson, Lisa A Mandl, Gideon N Aweh, Oliver Sangha, Matthew H Liang, Francine Grodstein. Total hip replacement due to osteoarthritis: the importance of age, obesity, and other modifiable risk factors. The American Journal of Medicine - 1 February 2003 (Vol. 114, Issue 2, Pages 93-98. Retrieved July 8th, 2011, www.ncbi.nlm.nih.gov/pubmed/12586227

(8) Bone Spur, WebMD, January 28, 2010. Retrieved July 8th, 2011, http://www.webmd.com/a-to-z-guides/bone-spur-topic-overview

(9) Simple Bone Cyst Imaging, Eu-Leong Harvey Teo, MBBS, FRCR, Wilfred CG Peh, MD, MBBS, FRCP(Glasg), FRCP(Edin), FRCR, May 25, 2011. Retrieved July 8th, 2011, http://emedicine.medscape.com/article/395783-overview

(10) osteoarthritis. (n.d.) Gale Encyclopedia of Medicine. (2008). Retrieved July 8 2011 from http://medical-dictionary.thefreedictionary.com/osteoarthritis

(11) Elizabeth W Karlson, Lisa A Mandl, Gideon N Aweh, Oliver Sangha, Matthew H Liang, Francine Grodstein. Total hip replacement due to osteoarthritis: the importance of age, obesity, and other modifiable risk factors. The American Journal of Medicine - 1 February 2003 (Vol. 114, Issue 2, Pages 93-98. Retrieved July 8th, 2011, www.ncbi.nlm.nih.gov/pubmed/12586227

(12) Excess Weight Predicts Younger Age at Hip and Knee Replacement, Peter Janiszewski, April 12, 2010. Retrieved July 8th, 2011, http://scienceblogs.com/obesitypanacea/2010/04/excess_weight_predicts_younger.php

(13) Aaron M Wendelboe, Kurt T Hegmann, Jeremy J Biggs, Chad M Cox, Aaron J Portmann, Jacob H Gildea, Lisa H Gren, Joseph L Lyon . Relationships between body mass indices and surgical replacements of knee and hip joints. American Journal of Preventive Medicine - November 2003 (Vol. 25, Issue 4, Pages 290-295. Retrieved July 8th, 2011, www.ncbi.nlm.nih.gov/pubmed/14580629

(14) The relationship between obesity and the age at which hip and knee replacement is undertaken. M. Changulani, MS, MRCS, Specialist Registrar; Y. Kalairajah, MPhil, FRCS(Orth), Consultant Orthopaedic Surgeon; T. Peel, BSc(Hons), Research Assistant; and R. E. Field, PhD, FRCS(Orth), Consultant Orthopaedic Surgeon, Director of Research Orthopaedic Research Unit. Journal of Bone and Joint Surgery - British Volume, Vol 90-B, Issue 3, 360-363. Retrieved July 8th, 2011, http://web.jbjs.org.uk/cgi/content/abstract/90-B/3/360

(15) Turgeon TR, Santore RF, Coutts RD. Influence of obesity on outcome following primary hip replacement surgery. American Academy of Orthopaedic Surgeons meeting; March 22-24, 2006; Chicago, IL. Paper 010. Retrieved July 8th, 2011, www.medscape.com/viewarticle/538540

(16) Explaining the use of the Harris Hip Questionnaire, Thomas J. Blumenfeld, MD. Retrieved July 8th, 2011, http://www.bananarepublican.info/Files/Harris_Hip_Score.pdf.

(17) Turgeon TR, Santore RF, Coutts RD. Influence of obesity on outcome following primary hip replacement surgery. American Academy of Orthopaedic Surgeons meeting; March 22-24, 2006; Chicago, IL. Paper 010. Retrieved July 8th, 2011, www.medscape.com/viewarticle/538540

(18) Obesity, Wikipedia. Retrieved July 8th, 2011, http://en.wikipedia.org/wiki/Obesity

(19) Ishak, M. A. and Morley, K. D. (1981), Deep venous thrombosis after total hip arthroplasty: A prospective controlled study to determine the prophylactic effect of graded pressure stockings. British Journal of Surgery, 68: 429–432. Retrieved July 8th, 2011, www.ncbi.nlm.nih.gov/pubmed/7016245

(20) Deep vein thrombosis, Wikipedia. Retrieved July 8th, 2011, http://en.wikipedia.org/wiki/Deep_vein_thrombosis

(21) Deep Vein Thrombosis and Obesity, Anne Collins Weight Loss Program. Retrieved July 8th, 2011, http://www.annecollins.com/weight_health/deep-vein-thrombosis-obesity.htm

(22) J. R. McLaughlin, MD, Director1; and K. R. Lee, MD, Clinical Associate Professor. The outcome of total hip replacement in obese and non-obese patients at 10- to 18-years. Journal of Bone and Joint Surgery - British Volume, Vol 88-B, Issue 10, 1286-1292. Retrieved July 8th, 2011, web.jbjs.org.uk/cgi/content/short/88-B/10/1286