Use of a revision cup for treatment of Zurich cementless acetabular cup loosening. Surgical technique and clinical application in 31 cases.

Loosening of the acetabular cup is one of the most common complications following total hip replacement and has an incidence rate of 1.8% to 36.8%. The objective of this study was to describe the surgical technique for the application of a cementless acetabular component specifically designed for treatment of cup loosening and preliminary clinical experience. The Kyon revision cup is composed of two components; the first is a perforated titanium outer shell with holes for 2.4 mm titanium screws, which is impacted into the acetabulum after removal of the loose cup and reaming of the acetabulum. It is secured with a variable number of screws. The second component is an inner plain titanium cup with an ultra-high-molecular-weight polyethylene insert, which is impacted into the outer shell to obtain press-fit stability. This revision cup was used in 31 dogs with cup loosening and a minimum follow-up period of six months. There were four intra-operative complications and two postoperative complications. The main intra-operative complication was difficulty inserting the inner cup into the outer shell. Postoperative complications included craniodorsal hip luxation in one dog, which was successfully managed, and cup loosening in another dog, which required explantation of the prosthesis. The main advantage of the revision cup appears to be increased implant stability afforded by screw fixation. Our initial clinical results in 31 dogs were promising; all but one dog had a successful clinical outcome.

Radiographic changes of the pelvis in Labrador and Golden Retrievers after juvenile pubic symphysiodesis: objective and subjective evaluation.

OBJECTIVES: The hypothesis of this study was that juvenile pubic symphysiodesis (JPS) results in pelvic changes that can be identified radiographically in adult dogs. METHODS: The medical records at the Clinica Veterinaria Vezzoni were searched for standard ventro-dorsal views of the pelvis of adult Labrador and Golden Retrievers that had undergone JPS or had not undergone surgery. The objective assessment of radiographs included the analysis of various pelvic measurements. Subjective evaluation of radiographs was undertaken by 18 specialists and 21 general practitioners and was based on five criteria relating to 1) the acetabular fossae, 2) the pubic symphysis, 3) the margin of the cranial pubic area, 4) the pubic rami, and 5) the obturator foramen. RESULTS: The radiographs of 42 Labrador Retrievers and 16 Golden Retrievers were evaluated. The most useful criteria were the radiographic measurement of the shape of the obturator foramen and two different ratios of length to width of the pubic rami; these values were significantly smaller in dogs after JPS. The pelvic canal width was the same in both groups. All objective measurements were repeatable within and between evaluators. The most reliable subjective criterion was number 4, followed by number 5 in Golden Retrievers and by 2 in Labrador Retrievers. CONCLUSION: Our objective and subjective evaluations were simple and yielded useful and repeatable results. There was no significant difference between general practitioners and specialists with regard to subjective evaluation, which indicates that these evaluation criteria can be used by small animal clinicians after minimal training.

Double pelvic osteotomy for the treatment of hip dysplasia in young dogs.

UNLABELLED: The aim of this study was to evaluate the feasibility of the double pelvic osteotomy (DPO) (osteotomy of the ilium and pubis) to treat clinical cases of hip dyplasia in young dogs instead of performing a triple pelvic osteotomy (TPO) (osteotomy of the ilium, pubis, and ischium). Candidates for DPO were 4.5- to nine-month-old dogs with coxofemoral joint subluxation and laxity, indicative of susceptibility to future development of severe hip dysplasia. The angle of reduction (AR) and angle of subluxation (AS) with Ortolani's sign, Norberg angle (NA), percentage of femoral head (PC) covered by the acetabulum, and the pelvic diameters and their relationships were measured clinically and radiographically before and after surgery. The surgical technique was similar to the TPO technique, but excluded ischiatic osteotomy. A DPO was carried out in 53 joints of 34 dogs; AR and AS values immediately postoperatively and at the one- and two-month follow-up examinations were significantly lower than the preoperative values (p <0.01). The complications encountered were mainly represented by implant failure (3.5%), partial plate pull-out (9.4%), and incomplete fracture of the ischial table (7.5%). Changes in PC and NA values obtained immediately after surgery and at the first and second follow-up examinations were significantly greater (p <0.01 both) than values obtained before surgery. Sufficient acetabular ventroversion was achieved to counteract joint subluxation and the modifications of AR and AS. The NA and PC direct postoperative values reflected a significant improvement in the dorsal acetabular coverage. CLINICAL RELEVANCE: Restoration of normal joint congruity (PC from 50 to 72%) and maintenance of the pelvic geometry without pelvic narrowing were the most intriguing features of DPO. The complications observed were greatly reduced when using dedicated DPO plates. Based on our experience, the morbidity after unilateral and bilateral DPO was lower than after TPO because elimination of the ischiatic osteotomy allowed for increased stability of the pelvis. The surgical technique of DPO was a little more demanding than TPO because of the difficulty in handling and rotating the acetabular iliac segment, but this difficulty was offset by elimination of ischial osteotomy.

Comparison of conservative management and juvenile pubic symphysiodesis in the early treatment of canine hip dysplasia.

OBJECTIVES: To evaluate the efficacy of juvenile pubic symphysiodesis (JPS) in a clinical setting for the early treatment of canine hip dysplasia (CHD), and to identify its indications and contraindications. METHODS: The final degree of CHD using the FCI (Fédération Cynologique Internationale) CHD classification in 5 Grades (A, B, C, D, E) was assessed at skeletal maturity in two homogeneous groups of dogs assessed at the age of 14 to 22 weeks and selected according to their susceptibility to CHD; one group was treated with JPS and one group was conservatively managed. Two hundred seventeen puppies completed the study; 81 were treated with JPS (group 1) and 76 were conservatively managed (group 2). A third group of 60 puppies with normal hips was followed as a negative control group. RESULTS: In group 1, 43.2% of the puppies had regression or a lack of progression of the disease in the final evaluation (Grade A & B), 25.9% had mild CHD (Grade C) and 30.9% had moderate and severe CHD (Grade D & E). In group 2, 23.6% of the puppies did not show any development of the disease (Grade A & B), 21.1% had mild CHD (Grade C) and 55.3% developed moderate to severe CHD (Grade D & E). Further investigation was done by comparing the severity of early signs of susceptibility to CHD with the final FCI Grades at adulthood in both groups. CLINICAL SIGNIFICANCE: The JPS procedure increased the odds of arresting or limiting the progression of CHD in mild to moderate grades of CHD, while it was less effective or ineffective in more severe forms.