Does Obesity or Smoking Affect Healing from Wrist Fracture Surgery? A Look at New Harvard Study

A recent study out of Harvard University and Beth Israel Deaconess Medical Center investigated the impact of obesity and smoking on recovery after wrist fracture surgery – specifically a distal radius break. Researchers concluded that obesity did not affect functional ability or bone healing (as measured by x-ray) in a clinically significant manner after 3 or 12 months. However, smoking reduced wrist function, range-of-motion, and bone healing at 3-months, but this difference was tempered in the long-run, with both smokers and non-smokers achieving “excellent” outcomes one year after surgery.

Altogether, the investigators concluded distal radius fracture surgery to be safe and effective regardless of smoking status or obesity, with neither impacting the long-term outcomes of patients. On balance, lifestyle interventions to lose weight or stop smoking should be implemented whenever possible and may be useful in improving post-surgical outcomes for a distal radius fracture in the shorter-term.

Background and study methods

Both obesity and smoking have been associated with worse bone health – the former is linked to a higher rate of musculoskeletal injuries and long bone fractures while the latter is known to reduce bone density, increasing fracture risk and delaying healing. Given the massive prevalence of both in the United States – about one third of adults in the US are obese (BMI>30 kg/m²) and about 14% smoke – this study represents a sizeable proportion of patients.

Distal fractures of the radius – the thick bone connecting your elbow to your wrist, along the thumb side – account for 5% to 20% of all emergency room fractures and 75% of upper extremity fractures. Treatment can be non-surgical (usually re-alignment and casting for ~6 weeks) or surgical – in the case of this study, plates and screws were used to stabilize bone fragments in the proper position to heal.

200 patient cases were reviewed for the study: 39 met the criteria for obesity, 20 were current smokers, and 32 were former smokers. The average age was 57 and 80% were women.

Two metrics were used to delineate wrist function during follow-ups: range-of-motion tests and a patient-completed survey called QuickDASH (Quick Disabilities of the Arm, Shoulder and Hand), which measured the ability of the patients to perform everyday tasks such as opening a jar. X-rays were taken to assess the healing of the break.

Data deep dive

Obesity

BMI had little effect on the treatment outcomes for patients: there was no statistical difference between the x-ray results or the range-of-motion testing between groups at any time point. The only metric that did differ was the patient-completed survey, for which those with obesity reported less functional ability at both the three- and twelve-month marks.

While these differences were statistically significant between the groups – suggesting that they were not chance findings – researchers deemed them not clinically significant. For one, the difference between the functional outcomes fell under the threshold for clinical importance (i.e., the groups may have had statistically different outcomes, but this difference was so small that it does not translate to clinically meaningful changes in function). Moreover, both groups finished their recovery well within the average functional score for the general population, leading the authors to conclude that “obesity has minimal impact on the outcomes” of distal radius surgery.

To this end, authors hypothesized that the differences in the survey results may be attributable to a lower functional baseline among those with BMI. In other words, obesity may hinder wrist function generally, irrespective of surgery, but it does not hamper healing after surgery.

Smoking

All three metrics – wrist function, mobility, and bone reunification – were impaired by smoking; non-smokers experienced the best outcomes, followed by former smokers, then by current smokers. Given the established link between smoking and poor bone health, this trend perhaps comes as no surprise.

That said, differences were most pronounced early on in recovery, corroborating previous research demonstrating that smoking delays bone healing rather than preventing it altogether. Physiologically, the delay is hypothesized to be caused by a multitude of factors, including reduced blood flow to bones and a disruption of bone metabolism by the chemicals in cigarettes.

As with obesity, despite a statistically significant difference in outcomes, all groups achieved “excellent” clinical outcomes in the longer-term, prompting researchers to label the surgery as safe and successful regardless of smoking status. Indeed, after an even longer follow-up at 2 years, there were no clinically significant differences found between the three groups for any outcome.

Surgical complications

Consistent with the good prognosis of distal radius fracture surgery, there were very few complications across the 200 patient cases:17 in total – 15 major (e.g., tendon rupture, carpal tunnel syndrome requiring surgery, opening of the surgical wound) and 2 minor (e.g., wound damage, painful scar).

Obesity was not correlated with an increased risk of complication. Intriguingly, there was a slight increase in major complications for non-smokers relative to current and former smokers, though investigators dismissed this as unrelated to smoking status.

More on distal radius fractures

Distal radius fractures most commonly occur after a fall onto an outstretched arm, causing pain, tenderness, bruising, and swelling. In some cases, the wrist can appear deformed or bent unnaturally.

If pain is severe or the wrist is crooked, it’s advisable to seek immediate medical attention at an urgent care or emergency room. After a physical examination and review of medical history, the doctor will typically take an x-ray to confirm the diagnosis.

Treatment options vary based on the severity and location of the break. For milder breaks, a cast or splint without surgery may be sufficient. More severe cases may require surgery, including using plates, screws, pins, or an external stabilizing frame to hold the healing bone fragments in place.

Prognosis for the injury is good – most can resume light activities within 1-2 months of cast removal or surgery, and more vigorous activities 3-6 months later.

Citations

1. Hall M.J., et al (December 2019). The Impact of Obesity and Smoking on Outcomes After Volar Plate Fixation of Distal Radius Fractures. Retrieved from https://www.jhandsurg.org/article/S0363-5023(19)31362-0/fulltext
2. Distal Radius Fractures (March 2013). Retrieved from https://orthoinfo.aaos.org/en/diseases–conditions/distal-radius-fractures-broken-wrist/
3. MacIntyre N.J. and Dewan N. (April 2016) Epidemiology of distal radius fractures and factors predicting risk and prognosis. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0894113016300278
4. Hales C.M., et al (April 2018). Trends in obesity and severe obesity prevalence in US youth and adults by sex and age, 2007-2008 to 2015-2016. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/29570750
5. Finkelstein E.A., et al (May 2007). The relationship between obesity and injuries among U.S. adults. Retrieved from https://journals.sagepub.com/doi/10.4278/0890-1171-21.5.460
6. Current Cigarette Smoking Among U.S. Adults Aged 18 Years and Older (n.d.). Retrieved from https://www.cdc.gov/tobacco/campaign/tips/resources/data/cigarette-smoking-in-united-states.html
7. Slemenda C.W., et al (October 1989). Cigarette smoking, obesity, and bone mass. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/2816518
8. Yoon, V., et al (February 2012). The effects of smoking on bone metabolism. Retrieved from https://link.springer.com/article/10.1007%2Fs00198-012-1940-y

Dr. John Knight

Dr. Knight is a renowned hand, wrist and upper extremity surgeon with over 25 years of experience. Dr. Knight is a Board Certified Orthopedic Surgeon and Fellowship trained. Dr Knight has appeared on CNN, The Doctors TV, Good Morning America, The Wall Street Journal, The Washington Post, Forbes, The Huffington Post, Entrepreneur, Oxygen network and more.