Tension band stabilisation of acetabular physeal fractures in four kittens

Abstract

The surgical repair of acetabular physeal fractures in four kittens using a screw and tension band technique is reported. This was an appropriate method for restoring articular congruency and improving pelvic alignment. All cases had an excellent outcome and full limb use following fracture repair. In kittens younger than 12 weeks, there is a possibility of premature fusion of the acetabular bone resulting in development of a deformed, shallow acetabulum and hip subluxation. However, surgery is still justified when there is pelvic canal narrowing to decrease the risk of future defecatory problems. Early implant removal in such young kittens may decrease the severity of deformity caused by premature physeal closure. In kittens of 16 weeks or older, the prognosis is good for normal acetabular development and implant removal is not necessary.

Fig 1

(a) Laterolateral and ventrodorsal radiographs of case 1 with a mildly displaced acetabular fracture after a fall. (b) Immediate postoperative radiographs showing good fracture alignment after stabilisation with two screws, washers and a tension band wire. (c) Laterolateral and ventrodorsal (frog leg) radiographs taken 7 months postoperatively (1 year of age) showing the healed acetabular fracture with no evidence of degenerative joint disease.

Fig 2

(a) Laterolateral and ventrodorsal radiographs of case 2 with an acetabular physeal fracture with displacement of the cranial fragment laterally and a right sacroiliac subluxation. (b) Immediate postoperative radiographs showing good fracture alignment after stabilisation with two screws, crossed K wires, polymethylmethacrylate and a tension band wire. (c) Laterolateral and ventrodorsal (frog leg) radiographs taken 2 months postoperatively showing the healed acetabular fracture.

Fig 3

(a) Laterolateral and ventrodorsal radiographs of case 3 with a markedly displaced acetabular fracture and pubic fractures that occurred after a road traffic accident. (b) Immediate postoperative radiographs showing good acetabular alignment, but there was still marked pelvic canal narrowing, this may have been caused by plastic deformation of the bone. (c) One year postoperatively radiographs show a shallow deformed acetabulum and hip subluxation

Fig 4

(a) Laterolateral and ventrodorsal radiographs of case 4 with a displaced acetabular fracture and pubic fractures that occurred after a road traffic accident. (b) Immediate postoperative radiographs showing good fracture alignment, but there is still some pelvic canal narrowing. (c) Implants were removed after 3 weeks in this kitten; these are the 1-year postoperative radiographs showing a slightly shallow acetabulum but otherwise minimal changes and a wide pelvic canal.

Fig 5

Time of closure of the acetabular physes measured from the radiographs of 26 kittens.

Fig 6

The immature cat pelvis and the acetabular physes.