Adjuvant Teriparatide Therapy for Surgical Treatment of Femoral Fractures; Does It Work?

Abstract

Purpose: Atypical femoral fracture (AFF), periprosthetic femoral fracture (PPFF) and femoral nonunion (FNU) are recalcitrant challenges for orthopedic surgeons. Teriparatide (TPTD) had been demonstrated to have anabolic effects on bone in various studies. We postulated that adjuvant TPTD after operation would enhance biologic stimulation for bone formation. We investigated (1) whether the adjuvant TPTD could achieve satisfactory union rate of surgically challenging cases such as displaced AFF, PPFF and FNU; (2) whether the adjuvant TPTD could promote development of abundant callus after surgical fixation; (3) whether the adjuvant TPTD had medically serious adverse effects.

Materials and methods: Thirteen patients who agreed to off label use of TPTD in combination of operation were included in this retrospective case series. Median patients' age was 68.7 years, and there were three male and ten female patients. Their diagnoses were nonunion in six patients and acute fracture in seven. Medical records and radiographic images were reviewed.

Results: Twelve of thirteen fractures were united both clinically and radiologically within a year after adjuvant TPTD. Union completed radiologically median 5.4 months and clinically 5.7 months after the medication, respectively. Callus appeared abundantly showing median 1.4 of fracture healing response postoperatively. There was no serious adverse reaction of medication other than itching, muscle cramp, or nausea.

Conclusion: Even appropriate surgical treatment is a mainstay of treatment for AFF, PPFF, and FNU, the current report suggested that adjuvant TPTD combined with stable fixation results in satisfactory outcome for the challenging fractures of femur.

Keywords: Atypical femoral fracture; Femoral nonunion; Femur; Periprosthetic fractures; Terip.

Fig. 1. A concise diagram describes the preoperative diagnoses, fixation devices and outcomes of 13 cases. The 13 patients could be categorized into two groups as acute fracture group and nonunion group. They were treated with various fixation methods and adjuvant TPTD, 12 patients resulting in union.

Fig. 2. The serial radiographs represent the course of atypical femoral fracture (Case 3) at subtrochanteric region with incomplete reduction. Each radiograph shows enlarged view of fracture and contains overview of proximal femur. The patient started to inject teriparatide (TPTD) after 11 days after surgery and kept using it for three months. Rapid growth of callus was observed between fracture fragments. (A) Immediate postoperative radiograph reveals slight varus reduction with a gap on lateral cortex and lack of contact on medial cortex. (B) Postoperative four-week radiograph reveals that abundant callus was formed with three weeks of TPTD injection. (C) Postoperative six month radiograph represents that the gap on both medial and lateral cortex was filled with abundant callus without trace of fracture line.

Fig. 3. Under the microscopic examination, callus specimen harvested from the patient (Case 8) who underwent revision surgery after adjuvant teriparatide for two months shows abundant bone, cartilage, and fibrous tissue formation (A: ×40, B: ×100; hematoxylin and eosin staining).