Introduction

Avascular necrosis (AVN) affecting locations other than the femoral head (AVNOFH) is a relatively uncommon clinical entity. A standardized treatment protocol for managing the early stages of AVNOFH remains elusive. Bisphosphonates (BPs) have demonstrated efficacy in preventing disease progression, bone collapse, and requirement for surgery in avascular necrosis of the femoral head.

Aim

To evaluate the clinic-radiological outcome of management of AVN other than the femoral head with intravenous zolendronic acid (ZA) and oral alendronate.

Patient Profile

Patients diagnosed with an early stage of AVNOFH

Methods

• Twenty patients diagnosed with early-stage AVNOFH were prospectively evaluated following treatment with a combination of weekly oral alendronate 70mg and yearly intravenous ZA (5mg) administered for one year.

• Clinical evaluation included visual analogue scale (VAS) for pain intensity, mean analgesic requirement, and range of motion.
• Radiographs and magnetic resonance imaging (MRI) were taken to classify the stage of AVN, monitor radiological collapse, and evaluate radiological progression or bone marrow edema (BME) resolution.
• All patients were followed up at 6 weeks, 3 months, every 6 months in the first 2 years, and annually thereafter.

Results

• Pain significantly decreased over time: Mean VAS pain score reduced from 7.72 at baseline to 3.12 in a mean duration of 4.3 weeks (3–13 weeks) (Figure 1)

• Analgesic requirements significantly decreased; patients achieved a 50% pain reduction within the first 6 weeks, and this lower usage remained consistent compared to baseline throughout the study

• Joint range of motion improved significantly in all patients, returning to normal limits within a year.

  Figure 1: VAS (visual analogue scale) pain score at all follow-up visits

  

  Radiological assessment

• MRI showed complete resolution of BME in 13 patients (72.2%) at 6 months and in 17 patients (94.4%) at 1 year.
• Radiological collapse was seen in 6 out of 18 patients at a mean follow-up of 35.3 months.
• Only one out of 18 patients enrolled required surgery

Figure 2: MRI assessment of the BME changes in patients till last follow-up

Table 1: Stage-wise proportion of cases underwent radiological progression, collapse, and surgery.

Conclusion

• The combination of yearly intravenous ZA and oral alendronate is well tolerated and not only provides pain relief but also prevents long-term radiological progression, thus obviating the need for surgery in the treatment of AVNOFH.

Reference
J. Orthop. Surg. Res. 2019; 14:112