Bone Mineral Density and Physical Performance of Female Patients 27 Years or Longer after Surgery for Adolescent Idiopathic Scoliosis

ABSTRACT

STUDY DESIGN: Retrospective cohort study. PURPOSE: To assess bone mineral density (BMD) and bone metabolism ≥27 years after surgery in female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS) during adolescence and to determine their associations with physical performance. OVERVIEW OF LITERATURE There are no studies investigating postsurgical BMD in middle-aged AIS patients. METHODS: This study included 23 patients who provided informed consent among 229 female patients with AIS who underwent spinal fusion from 1968 until 1988. Average age at the time of observation was 48.8 years. BMD was measured at the left femoral neck, and the levels of two bone metabolism markers–procollagen type 1 N-terminal propeptide (P1NP) and tartrate-resistant acid phosphatase 5b (TRACP-5b)–were measured from blood samples. Physical performance was measured using grip strength, sit-ups, sit-and-reach, side step, and standing long jump. RESULTS: Mean BMD was 0.784 g/cm2. According to the World Health Organization diagnostic criteria, one subject (4.3%) had osteoporosis, whereas nine subjects (39.1%) had osteopenia. In patients with osteoporosis or osteopenia, P1NP and TRACP-5b levels were high, and BMD loss was because of high metabolic turnover. All calculated standard scores for physical performance were lower in the study cohort than in healthy individuals. There was a positive correlation between BMD and the standard score for grip strength, whereas there were weak positive correlations between BMD and the standard scores for side step and standing long jump. CONCLUSIONS: In female AIS patients who underwent spinal fusion in adolescence, 4.3% and 39.1% had osteoporosis and osteopenia, respectively, ≥27 years after surgery. Exercise performance of these patients was poor compared with the national standards. In these patients, increased physical activity should be encouraged to prevent BMD loss in middle age.