Published 12/31/2023
Terry Stanton

Tracking Postoperative Weight Gain Trends in Ankle Fracture Patients

A study examining weight changes in patients after surgery for ankle fracture found that although most did not experience weight and BMI changes in the early postoperative period, after 6 months, patients recovering from ankle open reduction and internal fixation (ORIF) gained an average of about 10 pounds and 1.5 BMI points. By 1 year, patients gained about 20 pounds and 3 BMI points, on average.

The investigation, presented by Cameron G. Thomson, MD, orthopaedic resident at Brown University, is a retrospective study of patients treated at a level 1 trauma center or a level 3 community hospital between Jan. 1, 2018, and June 30, 2021. Patient records were reviewed for weight data at their outpatient postoperative visits at about 2 weeks, 6 weeks, 3 months, 6 months, and 1 year. Patients were excluded from analysis if their charts did not have complete weight data up to three months out from surgery or if their weight data were copied and pasted from their previous visits.

Table 1 Weight and BMI at the postoperative year following ankle fracture. SD, standard deviation; * indicates statistical significance. Post-op, postoperative follow-up visit.
Courtesy of Cameron G. Thomson, MD

During the study time period, there were 526 ORIF surgeries on ankles performed at the institutions by one of three foot and ankle trauma specialists. Of those cases, 56 patients (10.6 percent) met inclusion criteria.

The mean age at surgery was 44.6 years. There were 27 women and 29 men. At the time of surgery, the mean weight was 198.3 lbs and BMI was 30.4 kg/m2. Table 1 shows mean time to follow-up, mean weight, BMI, and changes at each postoperative visit. The mean weight at first postoperative visit was 197.8 lbs and BMI was 30.4 kg/m2 (P >0.05). Six weeks postoperatively, the mean weight and BMI were 197.5 lbs and 30.4 kg/m2, respectively (P >0.05). At 3 months postoperatively, the mean weight and BMI were 199.5 lbs and BMI 30.7 kg/m2 (P >0.05). At 6 months, the mean weight and BMI were 207.9 lbs and 31.9 kg/m2 (P >0.05). After 1 year, the mean weight and BMI were 219.2 lbs and 33.5 kg/m2 (P = 0.0491 and 0.0330, respectively).

In a subgroup analysis of patients within different preoperative BMI groups (<25, 25–29, 30–34, and ≥35), the same weight increase (about 20 lbs) and bmi increase (about 3 points) were observed across all bmi groups after 1 year.></25,>

Dr. Thomson said he and his colleagues were prompted to undertake the study in light of the fact that little literature exists on how weight changes after injury. “Ankle fractures are not only very common, but they also require patients to maintain several weeks to months of weightbearing restrictions,” he observed. “We hypothesized that the period of immobility could cause changes in weight.”

Dr. Thomson noted that the weight gain lagged the period of weightbearing restrictions. “Most patients recovering from ankle fracture surgery will have advanced their weight-bearing status by three months, and almost all will have advanced by 6 months. Thus, this lag could represent ongoing mobility issues resulting from a poor surgical outcome or perhaps a new baseline, ‘inactive norm,’ that the patient has established from habits learned while under weight-bearing restrictions.”

Addressing study limitations, Dr. Thomson noted that because the study is a retrospective analysis, many patients’ charts lacked accurate weight data at each postoperative visit; thus, the overall number of patients included in analysis was relatively small. Second, he said, “We did not analyze injury pattern but instead looked at all operative ankle injuries; some patients might have had more severe injuries than others and required longer period of immobilization/weight-bearing restrictions.” Finally, he said, “Our study was not free from loss to follow-up; several patients did not attend their 1-year follow-up, presumably because they were feeling well and had no concerns; thus, our results could be biased toward those with less-than-ideal outcomes who might be more at risk of weight gain compared to those with good outcomes and a faster recovery.”

Despite these limitations, the authors commented, “our study shows that weight gain after ankle fractures is significant and affects patients of all preoperative BMI groups, not just those who are already overweight or obese. In order to combat the growing overweight and obese problem in the United States, providers must be aware of this problem. Future studies could be done to help establish safe ways to both maintain weight-bearing precautions as well as maintain or achieve a healthy weight.”

Dr. Thomson’s coauthors of “Weight Changes after Ankle Fracture,” are Garrett Gordon, BS; Henry A Kuechly, BS; Jorge Figueras, BS; Tristian Epley, BS; and Richard Laughlin, MD.

Terry Stanton is the senior medical writer for AAOS Now.