The effect of early physical therapy after experimental stifle luxation in domestic pigeons (Columba livia domestica), managed with a combination of extracapsular stabilization technique and FESSA hinged linear external skeletal fixator (FESSA-HLESF)

Abstract

To evaluate the combination of the FESSA-HLESF/lateral collateral ligament prosthesis in repairing the stifle joint and to study the effect of early physical therapy, eight feral pigeons were divided in two groups. One started physical therapy one day post surgery, and the controls after the HLESF removal (3rd postoperative week). Healing was monitored with clinical, radiographic, pathologic and histologic criteria for six weeks. The combined technique stabilized the joint successfully, and clinically all birds used their limbs normally. Range of motion (ROM) was reduced in all birds (5o in flexion, 40o in extension). No significant difference was detected between the groups in ROM, thigh thickness and circumference or muscle/joint histology. Regressive lameness and pododermatitis (grade I) affected all birds. Fibrosis of the operated joint capsule, reduced synovial fluid and excessive callus were also detected (75% of cases). Muscle histology indicated atrophy of the operated limb (mean fiber Ø 49 µm). Joint histology revealed inaccurate reposition and osteophytes in 62.5%. Remodelling of subchondral and trabecular bone was unremarkable (<5 new osteoid areas/ bone). Common structural changes, associated with remobilization, were the presence of pannus/surface irregularities (25%) and radial clefts (12.5%). In conclusion, the clinical interpretation of a stabilized joint should be made with caution, as intraarticular structures are highly impacted during remobilization.