Background: Both pulsed electromagnetic field (PEMF) stimulation and sclerostin monoclonal antibody are useful for treating osteoporosis, but whether the two therapies have synergistic effects on both screw fixation quality and bone metabolism of ovariectomy-induced osteoporosis has not been reported.
Methods: We used ovariectomy to create a rabbit model of postmenopausal osteoporosis. Then, specimens were fixed with pedicle screws in the L4 vertebral body. Rabbits were randomly divided into an OVX control group, PEMF group, Scl-Ab group, and PEMF+Scl-Ab group. The PEMF group was given PEMF magnetic therapy, the Scl-Ab group was administered a subcutaneous Scl-Ab injection, and the PEMF+SclAb group received both therapies. The OVX group was injected subcutaneously with the same dose of saline instead. After eight weeks of treatment, the bone metabolism index, bone mineral density (BMD), and bone microstructural, biological, and biomechanical parameters were evaluated.
Results: BMD significantly decreased six months post-ovariectomy. Compared with that of the OVX group, the BMD of the PEMF, Scl-Ab, and PEMF+Scl-Ab groups increased by 20.3%, 19.9%, and 35.0%, respectively. The maximum pulling force of pedicle screws increased by 14.0%,15.0% and 19.1%, and the maximum failure power consumption of pedicle screws increased by 27.9%, 27.2% and 33.6%, respectively; these differences were statistically significant (P<0.05). The bone metabolism index and bone microstructure parameters of the PEMF+Scl-Ab group were more optimal than those in the single treatment group.
Conclusions: Both Scl-Ab and PEMF therapy can enhance the BMD and the mechanical strength of pedicle screws in osteoporotic bones of rabbits with postmenopausal osteoporosis. However, combination of the two measures has achieved even better results, yielding potential clinical application value.
Keywords: Drug therapy; combination; electromagnetic fields; orthopedic fixation devices; osteoporosis.