A Comparison Of Pelvic Limb Angular Values Of Pomeranian And Chihuahua Dogs With Normal And Medial Patellar Luxation Stifles Using Radiography And Computed Tomography

Abstract

Comparative study of angular values of femurs and tibias in Chihuahuas and Pomeranians with normal and MPL stifles by using radiography and CT scan was done to identify the angular values and relationship between pelvic limb angles and severity of MPL and to search for the suitable assessment method of limb deformity. Radiographic and CT scan images were obtained from 30 Chihuahuas (60 hind limbs) and 36 Pomeranians (60 hind limbs). In the frontal plane, anatomical and mechanical lateral proximal femoral angles (aLPFA and mLPFA), anatomical and mechanical lateral distal femoral angles (aLDFA and mLDFA), inclination angle (ICA), mechanical medial proximal and distal tibial angles (mMPTA and mMDTA) were evaluated. In the sagittal plane, precurvation angle (PA), anatomical caudal proximal and distal femoral angles (aCdPFA and aCdDFA), and mechanical caudal proximal tibial angle (mCdPTA) and mechanical cranial distal tibial angle (mCrDTA) were measured. In the transverse plane, femoral and tibial torsion angles (FTA and TTA) were evaluated. Means ± SD of all measured angles were reported and compared. In Chihuahuas, the significant differences of the measured values were found between those from radiography and CT scan including aLPFA, mLPFA, mMPTA, PA, aCdPFA, and aCdDFA in normal stifles (p≤0.05). From the CT scan, the angles related to severity of MPL were aLDFA, mLDFA, mMPTA, FTA and TTA. In Pomeranians, the significant differences of the measured values were found between those from radiography and CT scan including aLPFA, mLPFA, PA, and aCdPFA in normal stifles (p≤0.05). From the CT scan, the angles related to severity of MPL were aLDFA, mLDFA and FTA. This study reports the pelvic limbs goniometry values in both breeds and found limitation of the evaluation by radiography. Therefore, CT is recommended when the deformity is doubtful.