Simultaneous Bilateral Femoral Head and Neck Ostectomy for the Treatment of Canine Hip Dysplasia
Simultaneous bilateral femoral head and neck ostectomy (FHO) was performed on 15 dogs for severe bilateral hip dysplasia. A follow-up survey was performed 6 to 48 months after surgery to assess the postoperative recovery and activity levels of the operated dogs. All dogs had normal activity levels and were pain free according to their owners. Owner satisfaction regarding the outcome of the surgery was high. Simultaneous bilateral FHO was a viable surgical option for the treatment of painful bilateral hip disease in dogs, especially when other surgical options were not indicated or were cost prohibitive.
Introduction
Canine hip dysplasia is a bilateral, developmental disease characterized by instability of the hip joints leading to coxofemoral subluxation, synovitis, degenerative joint disease, pain, and lameness.1,2 Hip dysplasia may be identified radiographically as subluxation of the femoral head in young dogs and by osteoarthritis of the coxofemoral joint in older dogs. Diagnosis is based on history, orthopedic examination, and radiography.3 Orthopedic examination includes the evaluation of gait and stance, range of motion, and pain upon manipulation of the coxofemoral joints. In younger dogs, assessment of coxofemoral subluxation and reduction manipulation with the Bardens, Barlow, or Ortolani tests are also performed.4 Radiographic techniques used to evaluate hip dysplasia include standard ventrodorsal radiographs of the pelvis with the hip joints extended, University of Pennsylvania Hip Improvement Program (PennHIP) distraction radiographs, dorsolateral subluxation score, and dorsal acetabular rim radiography.4–8
In most cases, dogs with canine hip dysplasia are presented for evaluation when clinical signs become obvious to the owner, which can be as early as 3 months. The history and clinical signs usually include gait abnormalities such as lameness, bilaterally shortened strides, and bunny hopping, as well as decreased exercise tolerance and difficulty rising and climbing stairs. The onset of clinical signs tends to occur in a bimodal fashion. Clinical signs of hip dysplasia may first become apparent between 5 and 10 months of age and may arise from synovitis secondary to joint laxity.4 Later in life, usually after 3 years of age, clinical signs occur from osteoarthritic changes in the joints, which may include femoral periarticular osteophytes, subchondral sclerosis of the craniodorsal acetabulum, osteophytes on the cranial or caudal acetabular margin, or joint remodeling from chronic wear.5
Management of hip dysplasia is tailored to the individual dog. Factors that affect treatment include age at initial diagnosis, severity of clinical signs, breed and temperament, recommendations of the attending veterinarian, and an informed decision by the owner. Nonsurgical management of hip dysplasia includes nutritional recommendations, weight control, exercise restriction, physical rehabilitation, pain management, and nutraceutical supplements.4 Surgical options include juvenile pubic symphysiodesis, femoral head and neck ostectomy (FHO), triple pelvic osteotomy (TPO), and total hip replacement.9
The purpose of this study was to evaluate the clinical outcomes of 15 dogs with severe bilateral hip dysplasia that underwent simultaneous bilateral FHO.
Materials and Methods
Case Material
The medical records of all dogs referred to Veterinary Specialists of South Florida (VSSF) for evaluation of hip dysplasia between July 2000 and June 2003 were reviewed. Fifteen dogs that were treated with simultaneous bilateral FHO were included in the study. In each case, the history and clinical signs were typical of bilateral hip dysplasia. A radiographic diagnosis of bilateral hip dysplasia with significant subluxation was made by a board-certified radiologist based on ventrodorsal hip-extended views [Figure 1]. In all cases, there was <50% dorsal acetabular rim coverage of the femoral head of both coxofemoral joints. The data retrieved from the medical records included anesthetic protocols, surgical technique, and postoperative outcome.
Rationale for Surgery
Nonsurgical management was discussed with owners prior to surgical treatment. In most cases, nonsteroidal antiinflammatory drugs (NSAIDs) with or without chondroprotective agents had been tried without success. Additional nonsurgical therapies, including weight control, exercise management, and physical therapy were presented to the owners with the understanding that surgery would likely be necessary at some point. In all study cases, because of the severity of the clinical signs, owners elected to proceed with surgery immediately rather than attempt more extensive nonsurgical management. A general discussion of surgical options available for hip dysplasia was held with the owners so they could gain a better understanding of the pathophysiology of the disease and what procedures might work for their dog. Radiographic aids and plastic models were used to facilitate this discussion. Owners were given details on what could be expected during the postoperative period, as well as the likely long-term outcomes.
Surgical Procedure
All dogs were premedicated with a combination of morphinea (0.5 mg/kg intramuscularly [IM]), acepromazineb (0.01 mg/kg IM), and atropinec (0.02 mg/kg IM). Anesthesia was induced using ketamined (10 mg/kg intravenously [IV]) and diazepame (0.5 mg/kg IV) and was maintained with isofluranef in oxygen. Cefazoling (22 mg/kg IV) was given 20 to 30 minutes prior to surgery. Epidurals were not performed. Both surgical sites were clipped extensively. The perineum was also shaved to facilitate cleanliness during the immediate postoperative period. The dogs were placed in lateral recumbency. The craniolateral approach to the coxofemoral joint was used for all procedures.10
The acetabular ligament was transected with Mayo scissors. In some cases, the ligament of the femoral head was found to be ruptured at the time of surgery. The joint was luxated by externally rotating the femur to expose the femoral head. A Hohmann retractorh was used to stabilize the femoral head and neck. In all cases, the osteotomy was performed with an oscillating sawi from the medial aspect of the greater trochanter to the proximal aspect of the lesser trochanter.9 The cut surface of the femur was palpated for irregularities and smoothed using a curette if necessary. No tissue was interposed between the cut surface of the femur and the acetabulum. The joint capsule was closed using a monofilament absorbable suture in a simple interrupted pattern when possible. The surrounding muscles, subcutaneous tissue, and skin were closed routinely.10 Each dog was then repositioned with the opposite side up, surgically prepared and draped, and the procedure was repeated. No bandages were placed over the incisions. Postoperative radiographs were taken immediately to assure complete excision of the femoral head and neck.
Postoperative Care
Postoperative care included pain management, physical therapy, and general nursing care. Morphine (0.5 mg/kg IM) was administered every 6 hours as needed for pain, and NSAIDs (e.g., deracoxib,j carprofenk) were given orally the morning after surgery and were continued until the owner felt that the drugs were no longer needed. A 1-week course of antibiotics (cephalexinl 22 mg/kg per os q 8 hours) was also started the morning after surgery. Dogs were walked with a sling three to four times daily until they were able to bear reasonable weight on both hind limbs and were walking without assistance. Physical therapy included short walks that were slowly lengthened over time and passive range-of-motion exercises. After the dog’s discharge from the hospital, owners were instructed to facilitate supervised activity, such as leash walking. Swimming was encouraged after suture removal (10 to 14 days after surgery).
Follow-Up
A telephone survey was conducted with the owners between 6 months and 48 months after surgery. Twelve of the 15 owners were contacted. A physical examination and follow-up radiographs were offered to all owners, but they were performed in only four dogs. Owners were questioned about their dog’s activity level and quality of life. Specific information gathered from the owners included time to full recovery, evidence of pain, duration and current medications, concurrent orthopedic problems, and overall satisfaction with the surgical procedure. Results of the surgery were graded using the following scale: excellent = pain free, total weight bearing, normal activity level; good = pain free, slight lameness or gait abnormality with exercise, good activity level, fatigues with excessive exercise; fair = noticeable lameness, decreased activity level; and poor = severe lameness, severely decreased activity level. Ventrodorsal radiographs with the hips extended were taken in four dogs [Figure 2].
Results
The dogs in this study ranged in age from 6 to 25 months (mean 10.3 months). There were nine males (six castrated) and six females (four spayed). Body weights ranged from 19.0 to 30.9 kg (mean 25.9 kg). The following breeds were represented: Labrador retriever (n=5), golden retriever (n=4), rottweiler (n=1), and chow chow (n=1). Four mixed-breed dogs were also included in the study.
Surgery time ranged from 65 to 140 minutes (mean 90 minutes). In three dogs, ovariohysterectomy or castration was performed at the same time. Postoperative hospitalization ranged from 2 to 6 days (median 4 days). Four dogs were walking without assistance on the second postoperative day, and all dogs were walking within 4 days. Four dogs received supplemental sling walking at home for varying periods of time. No dogs required supplemental hospitalization after discharge.
Follow-Up and Outcomes
All owners (n=12) that were contacted were satisfied with the results of the surgery. Five owners graded the results of surgery as excellent, and seven considered the results to be good. No results were considered to be fair or poor. No dogs demonstrated any hip pain at the time of contact. Eight owners reported that their dogs recovered faster than what was predicted by the surgeon (approximately 3 months). Three owners thought that their dogs continued to improve for up to 2 years postoperatively and specifically mentioned stronger jumping, better use of stairs, and greater exercise tolerance over time. All owners contacted were satisfied with their dogs’ activity levels and reported that the dogs were running, playing, jumping, and using stairs. Seven of the dogs had a slightly abnormal gait only when running or after strenuous exercise. Four dogs had increased development of front-limb and thoracic musculature and slightly atrophied hind-limb musculature from disproportionate weight bearing by the front limbs.
The duration of postoperative NSAID treatment ranged widely. Most owners discontinued treatment 2 weeks postoperatively. While no dogs were perceived to be in pain by their owners at the time of contact, two dogs were receiving deracoxib.j These two dogs had subsequent orthopedic procedures performed for other problems. One dog underwent repair of a ruptured cranial cruciate ligament in one stifle 2 years after simultaneous bilateral FHO surgery. The other dog had a traumatic fracture of the left femur 2 months after simultaneous bilateral FHO. Both of these dogs were walking normally when the owners were contacted. All interviewed owners indicated that they would elect a simultaneous bilateral FHO surgery again if given the same surgical options.
Follow-up radiographs were evaluated in four dogs between 4 and 30 months after surgery. The findings in all cases were generally similar, in that the osteotomy margins of the femur were smooth and no osteophytes were present. No new bone formation within the acetabulum was noted on the radiographs, as reported previously.11
Discussion
Hip dysplasia is generally a bilateral disease that is diagnosed in younger dogs when it is severe.4 Although the mean age of the dogs in the study reported here was 10.3 months at the time of presentation, clinical signs of hip dysplasia had been present in most dogs for at least 1 to 3 months. The dogs in this study were representative of the breeds commonly affected by canine hip dysplasia.1,3
Alternative surgical options for simultaneous bilateral FHO include juvenile pelvic symphysiodesis, TPO, total hip replacement, and staged or unilateral FHO.9 No dogs in this study were candidates for juvenile pelvic symphysiodesis, since the recommended age for this procedure is 15 to 20 weeks of age.12,13 The youngest dog in this study was 24 weeks of age. Long-term results for juvenile pelvic symphysiodesis are not yet available.
Triple pelvic osteotomy increases the acetabular coverage of the femoral head to eliminate subluxation and improve joint stability.14 Clinical results after TPO have been very good with careful case selection.14 Simultaneous bilateral TPO may be done to minimize recuperation time.15 Ideally, TPO should be performed as soon as clinical signs develop but before joint degeneration is radiographically apparent.9 Dogs are not good candidates for TPO if they have radiographic evidence of degenerative joint disease, a shallow acetabulum, significant breakdown of the dorsal acetabular rim, or a ruptured acetabular ligament.9 Complications of TPO are uncommon and include narrowing of the pelvic canal, sciatic nerve injury, urethral impingement in male dogs, atonic bladder, and plate loosening.16
Total hip replacement is the definitive procedure for reestablishing normal joint mechanics and pain-free function of hips with osteoarthritis. Over 90% of dogs undergoing total hip replacement have an excellent or good level of function after surgery.17 The minimum age for performing total hip replacement is considered to be 10 to 12 months.17 The femoral physes should be closed so that no further longitudinal growth occurs, and such closure may occur at a later age in some breeds.17 The minimal ideal weight for total hip replacement in dogs is 16 to 18 kg in order to accommodate the acetabular cup.17 The ideal candidate for total hip replacement is a healthy young adult or older dog with progressive pain and loss of normal function from osteoarthritis of the hip.17 Complications include hip dislocation, implant loosening, implant failure, femoral fracture, infection, and neurapraxia of the sciatic nerve.18 Although the complication rate can be 6% to 9%, most complications are treated successfully, and overall owner satisfaction with this procedure is very high.18 Total hip replacement is significantly more expensive than other surgical treatment options.
Femoral head and neck ostectomy is a salvage procedure that is used in dogs with hip dysplasia when pain cannot be controlled with nonsurgical methods, or when other surgical therapies are either not indicated or cost prohibitive.19 By removing the femoral head and neck and allowing the development of a fibrous pseudoarthrosis, pain-free ambulation usually occurs.11 The procedure can be performed in dogs of any age or size, but in the authors’ experience, the best results are obtained in younger (i.e., <1 year) and smaller, lean dogs.
Recuperation after unilateral FHO or simultaneous bilateral FHO can be improved with proper physical therapy and pain medications.19 After FHO, dogs may have an obvious permanent gait abnormality from leg shortening and chronic muscle atrophy.20 The gait abnormality may be more obvious in dogs undergoing unilateral FHO, because of the structural difference between the two hind limbs after surgery. After simultaneous bilateral FHO, some dogs have shortened strides in the hind limbs and occasionally bunny hop, especially when running.
Hypothesized advantages of performing simultaneous bilateral FHO over staged bilateral FHOs include shorter overall recovery time, reduction in the number of anesthetic episodes and total anesthesia time, less expense for the owner, and symmetry in the recovering hind limbs. No comparison studies have been published to assess the differences between simultaneous or staged FHOs. The dogs in the present study had FHOs performed because their clinical signs were so severe that the owners were not satisfied with their quality of life. The dogs were exercise intolerant, had decreased appetites, and did not act like healthy puppies. The dogs were not good candidates for TPO, and the owners did not elect total hip replacement surgery either because of financial constraints or unwillingness to wait for skeletal maturity to address the problem. The FHOs were performed simultaneously because of the above hypothesized advantages.
A subjective scoring system was used in the study reported here, which provided useful information regarding the outcomes following simultaneous bilateral FHO. While owner perceptions were highly subjective, they did allow preliminary conclusions to be drawn on the outcomes of the procedure. A more quantitative grading system using force plate gait analysis would have been valuable in comparing functional recoveries from simultaneous bilateral and staged FHOs, but this test was unavailable to the authors.
Conclusion
Based on the results of this study, simultaneous bilateral FHO was a viable surgical option for dogs with bilateral hip dysplasia, especially when other procedures were declined by the owner. Recovery from simultaneous bilateral FHO was uneventful in all 15 dogs. The decision to perform simultaneous bilateral FHO was made only after an extensive discussion with the owner regarding the advantages and disadvantages of all indicated procedures and a full disclosure of the expected outcomes.
Morphine sulfate injection; Baxter Healthcare, Deerfield, IL 60015
Acepromazine maleate; Butler, Columbus, OH 43228
Atropine sulfate; Vedco Inc., St. Joseph, MO 64507
Vetaket; Phoenix Scientific, Inc., St. Joseph, MO 64503
Diazepam; Abbott Laboratories, North Chicago, IL 60064
Attane; Minrad Inc., Bethlehem, PA 18017
Cefazolin; G.C. Hanford Mfg., Syracuse, NY 13201
Hohmann retractor; Synthes, Paoli, PA 19301
Oscillating bone saw 518.01; Synthes, Paoli, PA 19301
Deramaxx; Novartis, Greensboro, NC 27408
Rimadyl; Pfizer Animal Health, Exton, PA 19341
Cephalexin; Ivax Pharmaceuticals, Inc., Miami, FL 33137
Citation: Journal of the American Animal Hospital Association 41, 3; 10.5326/0410166
Citation: Journal of the American Animal Hospital Association 41, 3; 10.5326/0410166
Preoperative radiograph of case no. 2, revealing bilateral hip dysplasia with severe bilateral coxofemoral subluxation and shallow acetabular cups. The letter L indicates the left limb.
Follow-up radiograph (5 months postoperatively) of case no. 2, revealing no new bone formation in the acetabular cups and smooth edges to the osteotomy sites. The letter R indicates the right limb.
