Cemented total hip replacement (cTHR) is commonly performed to treat intractable coxofemoral pain in dogs. While owners generally perceive a good outcome after the procedure, the longevity of the implant may be limited by complications such as infection and aseptic loosening. The objective of this retrospective study was to identify the prevalence of complications and radiographic changes following cTHR, and to identify factors that may predispose to a need for revision surgery. Medical records and radiographs from 97 dogs that underwent cTHR were evaluated for signalment, preoperative degree of osteoarthritis, technical errors, intra-operative culture results, and the post-operative radiographic appearance of the implant. The complications occurring in the intra-operative and short-term (<eight week) periods, and the radiographic appearance of the implant in the long-term (>eight week) time period were recorded. Mean (+/- SD) follow-up time was 1.1 +/- 1.6 years (range: 0-7.7 years). Seven dogs had a short-term complication and a revision surgery was performed in eleven dogs. Osseous or cement changes were radiographically detectable in the majority of cTHR. Eccentric positioning of the femoral stem and the presence of radiolucent lines at the femoral cement-bone interface were positively associated with the occurrence of revision surgery. The clinical significance of the periprosthetic radiographic changes is unclear and further investigation is warranted.
"Previous studies have shown that it is effective in pain relief and restoration of the joint function [1-4]. However, the long-term survival rate of the prosthesis can be affected by complications [5-9], including femoral fracture , osteolysis [10,11], osteopenia  and luxation of prosthetic components associated with the malpositioning of the acetabular component [6,7,13]. "
[Show abstract][Hide abstract] ABSTRACT: Total hip replacement (THR) is considered to be the most effective treatment option for advanced osteoarthritis of the hip in large breed dogs. However, a proportion of post-THR patients suffer prosthesis dislocation for various reasons, which may be addressed by a constrained acetabular prosthesis design. The study proposed a new THR with constrained acetabular component that aimed to decrease the incidence of postoperative dislocation while maintaining the necessary range of motion (ROM); and, through computer-simulated implantations, evaluated the ROM of the THR with and without malpositioning of the acetabular component.
A new THR with a constrained acetabular component that had an inward eccentric lining and a 60[degree sign] cut-out on the dorsal side was designed, and its computer-aided design models were implanted into the pelvic and femoral models reconstructed from the computed tomography data of six healthy Labrador Retriever dogs. The allowable and functional ROM of the implanted THR were determined via computer simulations. The contact patterns between the bone or the prosthetic components at extreme positions of the THR were analyzed. Influence of malpositioning of the acetabular component on the ROM was assessed.
The means (SD) of the functional ranges for flexion, extension, adduction, abduction, internal rotation and external rotation were 51.8[degree sign] (6.6[degree sign]), 163.3[degree sign] (7.3[degree sign]), 33.5[degree sign] (5.7[degree sign]), 74.0[degree sign] (3.7[degree sign]), 41.5[degree sign] (8.3[degree sign]) and 65.2[degree sign] (9.9[degree sign]), respectively. Malpositioning of the acetabular component by 20[degree sign] in one direction was found to reduce ROM in other directions (reducing lateral opening: flexion: 12[degree sign], adduction: 20[degree sign], internal/external rotations: < 20[degree sign]; increasing lateral opening: extension and abduction: < 16[degree sign]; reducing retroversion: extension: < 20[degree sign], abduction: 15[degree sign], external rotation: < 20[degree sign]; increasing retroversion: flexion: < 20[degree sign], abduction, adduction and internal rotation: 20[degree sign]).
From the computer-aided surgical simulations, the new THR was found to have sufficient functional ranges for flexion, extension, abduction, adduction and external rotation for Labrador Retrievers. Analysis of the malpositioning of the acetabular component suggests that accurate placement of the acetabular component is critical for achieving desirable ROM for daily activities.
[Show abstract][Hide abstract] ABSTRACT: Objective: The HELICA-Endoprosthesis is a new developed cementless hip endoprosthesis for dogs. The screw is anchored in the femoral neck and the cup is screwed in the acetabulum. The aim of this study was to evaluate its clinical application and to analyse the first experiences. Material und method: The HELICA- endoprosthesis was implanted in 23 dogs with severe hip osteoarthritis and a history of pain. In 14 cases the prosthesis was implanted on the left, and in 9 dogs on the right side. The dogs' body weight varied between 22 and 54 kg, their age between 10 months and 9 years. In all patients a clinical and radiological examination was performed 6 weeks postoperatively and in 15 dogs also 12 months after surgery. The femoral stem as well as the acetabular component of the prosthesis are solely screwed into position. An additional fixation with screws is not necessary, due to complete osteointegration of the implants. The prosthesis is avaliable in five standard sizes and the various components such as the stem, cup and head can be combined with each other. Results: In all cases we obtained a strong anchoring of the prosthesis with the bone. One pa- tient had a loosening of the cup and the femoral stem a few days after surgery. In another case loosening of the stem occurred 6 weeks after surgery. Both complications were due to technical errors in our learn- ing phase. The surgical revisions were successful. All dogs almost normally beared weight on the operated leg one day after surgery. Conclusion and clinical relevance: The advantages of the HELICA-endoprosthe- sis in comparison to alternative prostheses are the relatively easy surgical technique as well as the short operation time. The results of the first implanted prosthesis proved to be very good. A final conclusion can only be based on the results of a long-term study. The HELICA-endoprosthesis - a new cementless hip endoprosthesis for dogs
[Show abstract][Hide abstract] ABSTRACT: To evaluate the results of application, and identify complications, of the 2nd generation of Zurich Cementless Total Hip Replacement (ZCTHR).
Client-owned dogs (n=60) that had ZCTHR (n=65).
Dogs with ZCTHR (2001-2003) with a minimum follow-up > or =6 months were evaluated. Data included signalment, cup position, longest follow-up, complications, management of complications and outcome.
Mean follow-up was 22.68 months. Eleven cases (17%) had postoperative complications: femoral fracture (n=1; 1.5%), prosthesis luxation (7; 11%), cup loosening (2; 3%), and implant failure (1; 1.5%); 9 cases were successfully revised. Explantation of implants was performed in 1 case because of infection, and 1 dog was euthanatized after reluxation.
ZCTHR can restore function in dogs affected by disabling diseases of the coxofemoral joint. The press-fit fixation of the cup allowed for corrections in cases of incorrect positioning. Cases with aseptic loosening were revised successfully by impacting larger cups. Newer stems of this generation are shot peening treated to increase their resistance to breakage. In our cases, infection is a disastrous event, leading to implant removal. After resolution of complications, a successful final outcome was achieved in 97% of THR.
ZCTHR offers a reliable alternative for treating dogs with disabling diseases of the hip joints.
Veterinary Surgery 01/2009; 38(1):70-80. DOI:10.1111/j.1532-950X.2008.00466.x · 1.04 Impact Factor
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