Rehabilitation Following a Femoral Head Ostectomy and Total Hip Replacement on a Bengal Cat

Blair Hooser, Purdue University

Introduction
The patient was a 1 year old, male, neutered, Bengal cat. Within 1 year the patient sustained a capital physeal fracture of the right and left hip. This resulted in a femoral head ostectomy (FHO) of the right hip and a later total hip replacement (THR) of the left hip (1) (2) both performed at the Purdue University Veterinary Teaching Hospital (PUVTH). Physical rehabilitation exercises performed following both procedures at PUVTH included: assisted standing and weight shifting, warm pack, massage, stretching, passive range of motion, controlled walking, cavaletti rails, dancing, and the underwater treadmill. These exercises were also prescribed for the owners to continue at home. The patient was given Onsior and buprenorphine for pain management. Following completion of post-op physical rehabilitation, the patient had almost normal range of motion in both hips with some bilateral atrophy of the hip musculature.

FHO

Clinical Findings/Assessment
The patient presented to the PUVTH with a history of limping in the right pelvic limb. Radiographs had been taken at an emergency clinic and revealed a possible right femoral head fracture just prior to referral (Figure 1). Upon physical examination, a right hindlimb lameness and pain upon manipulation of the right hip were observed. The remainder of the physical exam was within normal limits. Blood was drawn for a complete blood count (CBC)/chemistry panel and no significant abnormalities were seen. Figure 1 Additional radiographs were obtained which confirmed the diagnosis of a capital physeal fracture of the right femoral head.

Treatments/Modalities
An FHO was performed at PUVTH. No surgical complications were encountered and the patient was discharged the following day on Onsior at home for pain relief. Postoperative radiographs were taken (Figure 2). The patient returned 2 weeks post-surgery for the beginning of physical rehabilitation. At this time, the incision had healed and the patient no longer required medications for pain. Gait analysis was normal and the Colorado State Pain Scale Assessment was 0/4. Assessment of the right hip showed decreased range of motion. Goniometry of the right hip in extension was 100 degrees and the limb girth of the right hind limb was 19.5cm at the mid-femur region. While walking and standing there was mild to moderate weight shifting off of the right pelvic limb, but the patient still used that limb with each step. The rehabilitation plan for the patient included improving functional walking, improving hip extension, and strengthening the muscles of the right pelvic limb. Pain management was also a major consideration for rehabilitation, since pain affects how the animal wants to use an affected limb, and thus would be counterintuitive to rehabilitation (3). Injuries to the musculoskeletal system can affect an animal’s proprioception and specific exercises are needed to help regain it (4). While at the PUVTH, several exercises were carried out with the patient. Assisted standing and weight shifting were performed on the Dino-disc to help with Figure 2 proprioception, muscle strength, and balance. The patient’s thoracic limbs were placed on the Dino-disc to add an element of instability and his back end was gently pushed from side to side and forward to back to encourage weight shifting from one leg to another. Warm packing and massage was done to increase blood flow and loosen the muscles (5). Passive range of motion and stretching of the pelvic limbs was performed to work on increasing flexibility, increasing synovial fluid flow, and decreasing muscle contracture. To work on strengthening, the patient did controlled walking for 10 minutes on flat, as well as uneven surfaces. This encourages the patient to use their leg as a whole unit; performing both extension and flexion. An element of unevenness can be added, such as a wobble board or short incline to add more proprioception to the exercise and encourage the patient to put more weight on the affected leg. To also promote coordination and increased flexion, the patient went over 10 caveletti rails (Figure 3). The owners were given instructions to continue exercises at home. Warm packing of the affected limb and massage were recommended for 10 minutes once per day. They were also instructed to perform 10-15 repetitions of passive range of motion (PROM) for each joint of the affected limb, 3 times a day, including stretching the right hip in extension for 10-15 seconds 10 times per session, for 3 sessions per day. To promote muscle strength and maintain movement, controlled walking was prescribed. The speed for controlled walking should be slow to encourage the use and placement of the right pelvic limb. To work on coordination as well as strength, in place of one of the daily walks, walking the patient through an obstacle course was recommended. To encourage coordination as well as joint motion, the owners were encouraged Figure 3 to make caveletti rails at home. Lastly, dancing 30 seconds 1-2 times per day was recommended to improve strength, coordination, and hip extension. A follow-up rehabilitation appointment was made approximately one month later. At that time, the patient’s flexion and extension of the right hip were normal and he had mild weight shifting lameness when standing, although he was ambulating very well. These exercises were performed the same as the previous visit: warm packing and massage, passive range of motion, controlled walking (decreased to 5 minutes), assisted standing and weight-shifting (on a Physioball). An underwater treadmill session was added to this visit (Figure 4). Underwater treadmills provide a vast number of advantages to rehabilitation (6). It was recommended to the owners that they continue all of the exercises previously mentioned, with the addition of assisted standing and weight-shifting. At this point, no further rehabilitation appointments were deemed to be necessary provided the owners continued the at-home exercises.

Outcomes/Results
With the rehabilitation exercises, the patient recovered almost normal range of motion in the right pelvic limb with only a mild decrease at maximal extension.

THR

Clinical Findings/Assessment
Eight months following the right FHO surgery, the owners reported that the patient tried to make a jump, missed his landing, and fell. The patient was referred to PUVTH for assessment of a suspected left capital physeal fracture. A CBC, chemistry and urinalysis revealed no significant findings. Orthopedic evaluation revealed crepitus on left hip palpation. Additional hip radiographs were obtained (Figure 5) confirming a capital physeal fracture of the left femoral head.

Treatments/Modalities
Surgical options of a FHO vs. THR were proposed to the owners. The owners elected to have a THR performed. The implant was placed without complications and postoperative radiographs were taken (Figure 6). The patient was later discharged on buprenorphine. The patient returned in approximately a month and a half post-op surgical repair for physical rehabilitation. On assessment, the patient had normal range of motion in his knees and tarsi. There was a slight reduction in hip extension bilaterally. His pain was a 0/4 on the Colorado State Pain Scale Assessment. In-house exercises performed included: warm packing and massage of the left hip and femur, assisted standing and weight-shifting, cavaletti rails at the lowest setting, and the underwater treadmill. Cold packing was also added to help reduce inflammation and pain at the end of the session. The exercises to be continued at home were controlled walking for 10 minutes a day and assisted standing and weight-shifting. They were also instructed to apply cold packing after each exercise session to reduce inflammation and pain.

Outcomes/Results
Figure 6 Approximately 9 weeks following left THR, the patient showed no signs of pain. Radiographs revealed a healing left THR. He was fully weight-bearing on all four limbs. There was some bilateral muscle atrophy in the pelvic limbs. Both pelvic limbs could be extended without difficulty and there was good range of motion. It was determined that the patient did not need to return for a follow-up appointment unless any there were any concerns.

Summary
While rehabilitation with dogs is a growing field, rehabilitation in cats is still relatively uncommon. Part of this may be the perceived difficulty of working with cats, however, if done properly, successful rehabilitation is still possible (7). This patient not only had successful rehabilitation, but also demonstrated that feline rehabilitation is possible. The overall goal of rehabilitation for both hips in this patient was to improve gait and stride, improve hip extension bilaterally, increase muscle mass and hip proprioception. Without the support of the implant, FHO’s require more postoperative rehabilitation than THR’s for the patient to regain as much function as possible (8). The patient would have to rely more heavily upon the muscles to hold the joint together, muscles that would have recently undergone atrophy from disuse (9). This is why he worked more heavily upon correct gait and range of motion with the FHO, with the idea that muscle mass would follow with increased exercise. However, with THR’s there is a concern with implant failure (10). Thus, rehabilitation was started later after surgery and cage rest was more strictly adhered to. Successful physical rehabilitation of this patient was accomplished with a combination of manual and modality therapies at home and also in hospital.

References
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