Comparison of osteotomy level with three different canine total hip replacement systems

Area of Science:

• Veterinary Orthopedics
• Biomechanical Engineering
• Surgical Techniques

Background:

• Numerous cementless total hip replacement (THR) systems exist for dogs.
• Differences in femoral osteotomy techniques and bone preservation in the calcar region are potential distinguishing factors.
• No quantitative comparison of osteotomy levels in canine THR has been previously performed.

Purpose of the Study:

• To develop and validate a method for quantifying the distomedial osteotomy level in canine THR.
• To compare the osteotomy levels among different canine THR systems.

Main Methods:

• Radiographic assessment of 33 dogs undergoing Helica or BFX THR, with osteotomy level quantified by three observers.
• Correlation analysis among observers using Spearman rank order correlation.
• Comparison of osteotomy levels between Helica, BFX, and Zurich THRs using non-parametric tests.

Main Results:

• High inter-observer correlation (R-values 0.87, 0.72, 0.60) validated the measurement technique.
• Helica implants showed significantly more proximal osteotomies (0.75 ± 0.22) than BFX (0.97 ± 0.13) and Zurich (1.1 ± 0.15) THRs (p < 0.001).
• BFX prostheses also had significantly more proximal osteotomies than Zurich THR (p < 0.05).

Conclusions:

• The developed radiographic method for quantifying osteotomy location is precise.
• Short-stemmed Helica implants are associated with more proximal femoral osteotomies compared to long-stemmed BFX and Zurich implants.
• Osteotomy levels differ significantly between Helica, BFX, and Zurich THR systems, with BFX being more proximal than Zurich.