A 6-month-old prepubertal entire domestic shorthair cat presented with bilateral closed femoral fractures due to unobserved trauma that had occurred up to 4 days prior. The cat had indoor/outdoor access and road trauma or a fall was considered likely. Radiographs revealed Salter Harris type-1 physeal fracture in the right distal femur, left distal femoral diaphyseal fracture and fracture of the left femoral neck. Surgical stabilisation with internal fixation was performed. The right limb was treated by cross pins in the distal femur. The left femoral fracture was repaired with a laterally applied 1.5/2.0 veterinary cuttable bone plate and screws, and left femoral head and neck osteotomy was performed. The cat was discharged on meloxicam (0.05 mg/kg orally q24h) and with instructions for 6 weeks of strict cage-style rest. The owner was encouraged to perform passive range-of-motion exercises of the stifles and left hip and allow supervised walking exercise in the house. Effective physical therapy was not performed owing to the cat's demeanour.
Two weeks postoperatively the cat showed good clinical recovery and was walking well with mild bilateral lameness. Periarticular thickening of the right stifle joint and mildly reduced joint flexion were noted, but no comment regarding left stifle range of motion was recorded. A course of pentosan polysulfate injections (3 mg/kg SC, weekly for 4 weeks) was initiated. At 6 weeks postoperatively, the owner reported the cat had developed worsening left hindlimb lameness and difficulty using the litter tray over several weeks. On examination, there was weightbearing left pelvic limb lameness with stiff hindlimb gait. The left stifle joint was fixed in mild extension, with minimal flexion possible even under anaesthesia. There was a large firm fracture callous palpable and the distal left quadriceps muscle was firm, non-painful and fixed distally to the femur. Proximally, the quadriceps muscle was soft with normal consistency. Radiographs showed stable implants and advanced fracture healing with marked periosteal callous formation. A diagnosis of left quadriceps contracture was made. The right stifle and both hips demonstrated an acceptable range of motion and comfort on palpation at that time.
Surgery was performed, including removal of the bone plate and screws, mobilisation of adhesions between the quadriceps and femur with placement of a free fat graft between the bone and muscle and attachment of a dynamic flexion apparatus. The proximal apparatus was created by inserting three threaded mini-external fixation pins in the caudal aspect of the left ischium that were incorporated into a blob of hardware acrylic cement (Knead-it; Selleys) in which a metal hook was also embedded. The distal apparatus was a single circular external fixator ring block secured in the distal tibia with two crossed wires. The proximal and distal elements were connected via elastic bands to maintain stifle flexion. Normal range of stifle flexion was possible immediately after surgery. The cat was discharged to the owner with ongoing oral meloxicam and oral buprenorphine (0.01 mg/kg orally q12h). The stifle was maintained in a flexed position when the cat was confined, but the apparatus was unhooked when it was possible to have supervised house exercise, to encourage walking.
In a follow-up examination 2 weeks later (8 weeks post-fracture repair), the left stifle demonstrated near normal range of motion in flexion. Mild wire tract discharge was present distally and there was loosening of the ischial attachment so the flexion apparatus was removed. Decreased flexion (90 degrees) was noted in the right stifle at that time consistent with developing quadriceps contracture on the contralateral side. Physical therapy was initiated in hospital in an attempt to prevent progression of contracture. This comprised passive range of motion exercises of both stifles and hips and muscle stretching performed in 10-15 min sessions twice daily under anaesthesia, owing to patient demeanor. After 1 week the right hindlimb showed no persistent improvement in stifle range of motion. When physical therapy was not performed for over 12 h there was notable decrease in stifle range of motion.
Surgical intervention on right hindlimb was performed as described for the left side, although implants were embedded in bone and were not recovered. The cat remained hospitalised or was treated as an outpatient daily over this period with ongoing meloxicam and buprenorphine, and once- or twice-daily physical therapy on both hindlimbs. The flexion apparatus was connected with the right stifle joint in full flexion while the cat rested, but was released at other times to promote walking and exercise. The fixator on the right side loosened at the site of the ischial pins and was removed after 2 weeks. After removal of the dynamic fixation device daily physical therapy was continued. Despite physical therapy, the range of movement in the left hindlimb became progressively restricted to approximately 50 degrees of motion, and in the right limb contracture had worsened to 60-70 degrees of movement. Surgery was then repeated on the left side to free the reformed adhesions, and reattach a dynamic flexion apparatus (12 weeks after fracture repair). The apparatus was also maintained for 1 week until it loosened. Daily physical therapy was continued after fixator removal; however, this was not adequate to maintain range of motion, even while hospitalised. Meloxicam was withdrawn and following a washout period of 48 h prednisolone treatment was initiated empirically in an attempt to limit reoccurrence of fibrosis and formation of adhesions. Prednisolone therapy commenced approximately 13 weeks post-fracture repair, initially at 1.85 mg/kg orally q12h for 3 days then tapered over time. By day 10 the cat was on 0.93 mg/kg prednisolone q48h this was continued for 8 weeks in total. No further physical therapy was performed.
Within 3 days of initiating prednisolone treatment, the cat showed both a lack of worsening and significant improvement in range of motion in both hindlimbs, and after 4 weeks of treatment, the left stifle had a normal range of movement, and the right was only slightly decreased. The cat was continued on 0.93 mg/kg q48h for 4 more weeks. Two weeks after prednisolone treatment ended, and approximately 23 weeks post-fracture repair, a follow-up evaluation was performed. The cat had maintained good range of motion in both hindlimbs, and contracture had not reoccurred. Fifteen months later the cat was represented for examination and radiographs. The owner reported that the cat had continued to improve over time, becoming more adventurous and mobile particularly during jumping. Occasional self-limiting right hindlimb lameness was noted. On palpation both quadriceps muscles felt soft, compliant and non-painful, and near-normal stifle joint range of motion had been maintained. Mild right stifle crepitus was noted and radiographs confirmed mild stifle osteoarthritis; however, the abnormal periosteal callus associated with the femurs had remodelled.