Alterations in bone mineral density and lower extremity lean mass after hip arthroscopy in a professional female Ironman triathlete: a case study

Biometric Changes Up to 2 Years After Hip Arthroscopy in National Collegiate Athletic Association Division I Athletes

Background

Patients who undergo hip arthroscopy for femoroacetabular impingement (FAI) require lower extremity immobilization for an extended period of time. Periods of immobilization combined with surgery have been associated with decreased muscle mass and bone mineral density (BMD).

Purpose/Hypothesis

The purpose of this study was to characterize postoperative body composition and BMD changes after arthroscopy for FAI. It was hypothesized that both lean mass and BMD would decrease postoperatively and then normalize over time.

Study Design

Case series; Level of evidence, 4.

Methods

This was a retrospective review of 23 National Collegiate Athletic Association Division I athletes who underwent hip arthroscopy between 2017 and 2019 and had a dual-energy x-ray absorptiometry scan preoperatively and at 3, 6, 12, or 24 months postoperatively. Linear mixed-effects models were used to compare pre- with postoperative lean and fat mass values for the total body and total leg (both operative and nonoperative sides) as well as trunk, pelvic, and spinal BMD. For total-leg, femur, and femoral BMD, linear mixed-effects models were used to evaluate the influence of time, side (operative vs nonoperative), and their interaction on each outcome measure.

Results

Regarding pelvic BMD, compared with baseline (mean, 1.41 g/cm2 [95% CI, 1.33-1.49]), significant decreases were seen at postoperative 3 months (mean, 1.36 g/cm2 [95% CI, 1.28-1.45 g/cm2]; P < .001) and 6 months (mean, 1.39 g/cm2 [95% CI, 1.27-1.52 g/cm2]; P < .01) but not at 12 months (mean, 1.42 g/cm2 [95% CI, 1.33-1.51 g/cm2]; P = .319). Total-leg BMD for the operative side increased significantly from baseline (mean, 1.52 g/cm2 [95% CI, 1.43-1.61 g/cm2]) to ≥2 years postoperatively (mean, 1.56 g/cm2 [95% CI, 1.47-1.65 g/cm2]) (P = .005). Combined leg fat mass was increased from baseline (mean, 6427 g [95% CI, 4855-7999 g]) to ≥2 years (mean, 11645 g [95% CI, 7845-15,446 g]) (P < .01). There were no significant differences in total-body fat or lean mass or combined-leg lean mass.

Conclusion

In this patient population, a postoperative decrease in pelvic BMD that resolved by 12 months and an increase in total-leg BMD on the operative side at ≥2 years were observed. While hip arthroscopy for FAI may have significant benefits for long-term body composition and bone mass, clinicians should be aware of the potential implications of decreased bone mass for up to 12 months postoperatively.

Retraining and Nutritional Strategy of an Endurance Master Athlete Following Hip Arthroplasty: A Case Study

Retraining and resuming competition following surgery is challenging for athletes due to the prolonged period of reduced physical activity and subsequent alteration of body composition and physical performance. This is even more challenging for master athletes who endure the additional effect of aging. Within this context, the purpose of this study was to evaluate the feasibility and benefits that evidence-based nutritional and training recommendations could have on the time course of reconditioning and retraining following hip arthroplasty in an endurance master triathlete. During 38 weeks (from 6 weeks prior to surgery through to the return to competition in week 32), the athlete was provided with detailed training and nutritional recommendations. Dietary intake (via the remote food photographic method), body composition (via DXA), peak oxygen uptake (VO_2peak), peak power output (PPO), cycling efficiency (GE), and energy availability (EA) were assessed 6 weeks pre- and 8, 12, 18, 21, and 25-weeks post-surgery. Training load was quantified (via TRIMP score and energy expenditure) daily during the retraining. Total body mass increased by 8.2 kg (attributable to a 3.5-4.6 kg increase in fat mass and lean mass, respectively) between week -6 and 8 despite a reduction in carbohydrate (CHO) intake post-surgery (<3.0 g/kg body mass/day). This was accompanied with a decrease in VO_2peak, PPO, and GE due to a drop in training load. From week 7, the athlete resumed training and was advised to increase gradually CHO intake according to the demands of training. Eventually the athlete was able to return to competition in week 32 with a higher PPO, improved VO_2peak, and GE. Throughout retraining, EA was maintained around 30 kcal/kg Lean Body Mass/day, protein intake was high (~2 g/kg/day) while CHO intake was periodized. Such dietary conditions allowed the athlete to maintain and even increase lean mass, which represents a major challenge with aging. Data reported in this study show, for the first time, the conditions required to recover and return to endurance competition following hip surgery.

Is there a correlation between outcomes after hip arthroscopy for femoroacetabular impingement syndrome and patient cortical bone thickness?

 

In order to determine the associations between age, sex, cortical bone thickness (CBT), and outcomes following hip arthroscopy for FAIS, a retrospective study of patients undergoing hip arthroscopy for FAIS from a single institution from 2012 to 2014 was performed. Based on preoperative radiographs, femoral cortical index (FCI) and femoral canal-to-calcar ratio (FCC) were used as measures of CBT and used to classify patients using the Dorr classification. Linear and logistic regression was used to determine whether CBT was predictive of 2-year patient reported outoutcomes. Patients were stratified by sex and age (<45 or =45 years old) to determine whether variables were potential effect modifiers on the association between outcomes and CBT. A total of 108 patients were included in the study, with 27 patients in each of the following groups: females <45, females =45, males <45, and males =45 years. The results showed that at 2-year follow-up, all groups demonstrated significant improvements in reported outcomes (HOS-ADL, HOS-SS, and mHHS) (p<0.001). Females =45 scored significantly worse than other groups on all scores (p<0.05 for all). Chi-square test for trend showed a linear by linear association between Dorr classification type and gender/age group (p=0.018). Analysis of the whole study population showed a linear association between FCC and HOS-ADL and mHHS scores. However, CBT measures were not predictive of achieving MCID. In conclusion, patients undergoing hip arthroscopy for FAIS, older female patients had the worst patient-reported outcomes and lowest CBT measures. Furthermore, FCC is independently associated with the HOS-ADL and mHHS.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III

What is known about the subject

Among patients undergoing hip arthroscopy for FAIS, female patients over the age of 45 have been reported to be at risk for inferior post-operative outcomes. Meanwhile, this patient population is also the most at risk for deteriorating CBT.

What this study adds to existing knowledge

This study demonstrates that female patients with FAIS over the age of 45 have inferior CBT indices than their male and younger-aged counterparts. Furthermore, this study presents an association between the FCC and 2-year patient-reported outcome measures, suggesting that CBT characterization may withhold prognostic value.