Canine total hip replacement using a cementless threaded cup and stem: a review of 55 cases

Complications and Long-Term Outcome in 30 Canine Total Hip Arthroplasties Using a Second-Generation Selective Laser Melted Screw Cup

OBJECTIVE

 The aim of this study was to report complications and outcomes of a cementless total hip arthroplasty (THA) system with a second-generation selective laser-melted screw cup (SCSL).

STUDY DESIGN

 All THA using the SCSL performed at a single institution between January 2017 and November 2022 were retrospectively evaluated. Patients with a minimum follow-up period of 12 months and complete medical records were included and analyzed for radiographic and clinical outcomes.

RESULTS

 Thirty THA with SCSL in 23 dogs were included in this study. Complications were observed in seven hips, comprising two minor and five major complications, with two hips experiencing two major complications. Among these seven major complications, six were associated with the femoral implant and one involved cup luxation. Of the 30 THA, 4 were explanted, while 26 remained in place for a median follow-up of 17.5 months (range, 12-38 months).

CONCLUSION

 No cases of late aseptic loosening were observed with SCSL. THA using SCSL helps reduce cup-associated complications and is appropriate for THA surgery, and the overall complication rate is comparable with that of other single-implant systems. Nevertheless, four hips were explanted.

Poor success rates with double pelvic osteotomy for craniodorsal luxation of total hip prosthesis in 11 dogs

OBJECTIVE

To report the outcome of double pelvic osteotomy (DPO) for craniodorsal luxation of total hip replacement (THR).

STUDY DESIGN

Retrospective case series.

ANIMALS

Eleven client-owned animals.

METHODS

Dogs with craniodorsal luxation of THR and high angle of lateral opening (ALO) were considered candidates for DPO. The ALO and the version angle (VA) were measured on pre- and post-DPO radiographs. Pre- and post-DPO ALO and VA were compared using a Wilcoxon signed-rank test. Clinical and radiographic outcomes were assessed at 2 and 6 months post-DPO.

RESULTS

Eleven DPOs were performed on 11 dogs after THR luxation. The ALO was reduced from a median of 66.2° (range 37.3-73.1°) to 55.9° (range 13.2-60.0°) (p ≤ .001), and VA increased from a median of 25.6° (range 6.8-51.9°) to 35.3° (range 15.1-51.7°) (p ≤ .03). Craniodorsal luxation recurred in five dogs and was managed with closed reduction (one dog), capsulorrhaphy (one dog), or repositioning of the acetabular cup (three dogs). The median clinical follow-up duration was 19.7 months (range 3.4-73.0). In the long term, seven dogs required explantation (five aseptic loosenings, two infections) (median 8.2 months, range 2.6-50.6).

CONCLUSION

Reluxation was frequent after DPO, 5/11 dogs requiring additional procedures, including three cup revisions. The long-term outcome was considered to be poor due to frequent explantation.

CLINICAL SIGNIFICANCE

Double pelvic osteotomy may be considered to avoid cup replacement when managing craniodorsal THR luxations in dogs but is not recommended due to high complication rates.

Case report: Total hip replacement using Innoplant system in a dog with chronic hip luxation and contralateral pelvic limb amputation

A 6-year-old female neutered Border Collie presented with an inability to walk. The patient had undergone pelvic limb amputation over a year prior. Orthopedic examination revealed discomfort during hip manipulation, and radiographic examination revealed chronic hip luxation. Total hip replacement was performed using the InnoPlant system, which includes modular screw-in cementless pieces to improve implant stability. Cage rest was for the first four postoperative weeks. Subsequently, assistance was provided while standing until the patient could stand unassisted at 10 postoperative weeks. The clinical and radiological outcomes were excellent 3 months postoperatively. Since it is a new system, there are no data regarding the use of the components of the Innoplant system in dogs with a contralateral amputated pelvic limb. This is the first report describing the use of the Innoplant system for total hip replacement in a dog with a contralateral amputated pelvic limb. Based on the clinical outcomes of this case, the use of an Innoplant prosthesis can be an effective treatment option for dogs with contralateral amputated limbs.

Clinical evaluation of total hip arthroplasty for osteoarthropathy secondary to septic hip arthritis

To investigate the clinical efficacy and prognosis of total hip arthroplasty (THA) in patients with osteoarthropathy secondary to septic hip arthritis. A total of 100 patients with osteoarthropathy secondary to septic hip arthritis who underwent surgery in our hospital from December 2010 to December 2021 were selected. Operative data were summarized. Moreover, preoperative and postoperative differences in Harris score, Western Ontario and McMaster Universities Osteoarthritis Index score, Visual Analogue Scale score, hip mobility were compared. Due to hospital transfer, the epidemic of COVID-2019 and other reasons, 10 patients were lost to follow-up and finally 90 patients were recorded. According to the results, the mean operation time (OT) was 1.78 ± 0.32 (hour), the mean intraoperative blood loss (BL) was 586.62 ± 31.66 (mL), the mean red blood cell (RBC) transfusion was 3.84 ± 0.75 (U), and 2 cases were positive, and 88 cases were negative for Trendelenburg sign. Postoperatively, the unequal length of the lower limbs and the Visual Analogue Scale score were significantly lower than that of the preoperative, while the Western Ontario and McMaster Universities Osteoarthritis Index score, Harris score, and hip joint range of motion were significantly higher than those of the preoperative (P < .05). At the last follow-up, all the incisions healed with no deep infections, 1 case suffered from transient sciatic nerve palsy, 2 cases had intermuscular venous thrombosis, and 2 cases who occurred hip dislocation recovered after treatment. THA surgery for osteoarthropathy secondary to septic hip arthritis has a good effect, relieving the patient's pain effectively, improving prognosis and joint mobility. For osteoarthropathy secondary to septic hip arthritis, THA may be meaningful in terms of prognosis.

Fluoroscopic Categorization of Cementless Acetabular Component Positioning

OBJECTIVES

 The purpose of this study was to evaluate a fluoroscopic method of angle of lateral opening (ALO) categorization based on identification of the visible portion of a pre-existing, circular recess within the metal shell of the BioMedtrix BFX acetabular component, which projects as an ellipse at clinically relevant ALO values. Our hypothesis was that there will be an association between the actual ALO and the categorization of ALO based on identification of the visible portion of the elliptical recess on a lateral fluoroscopic image at clinically relevant values.

METHODS

 A custom plexiglass jig was fitted with a two-axis inclinometer and a 24 mm BFX acetabular component attached to its tabletop. Fluoroscopic reference images were obtained with the cup positioned at an ALO of 35, 45 and 55 degrees with a fixed 10 degrees of retroversion. Thirty study fluoroscopic images (10 images at each ALO) were obtained based on randomization at an ALO of 35, 45 and 55 degrees (±0.5 degrees) with 10 degrees of retroversion. The order of the study images was randomized, and a single, blinded observer categorized the 30 study images as representing an ALO of 35, 45 or 55 degrees by comparison to the reference images.

RESULTS

 Analysis showed perfect (30/30) agreement with a weighted kappa coefficient of 1 (95% confidence interval: -0.717 to 1).

CLINICAL RELEVANCE

 The results demonstrate that accurate categorization of ALO can be achieved using this fluoroscopic method. This method may prove to be a simple but effective method of estimating intraoperative ALO.

Effect of Stem Positioning on Biomechanical Performance of a Novel Cementless Short-Stem Canine Total Hip Implant

OBJECTIVE

 The aim of this study was to evaluate the effect of stem positioning on the biomechanical performance of a novel, collared, short-stem total hip implant under compression and torsion ex vivo.

STUDY DESIGN

 Six canine cadaveric femurs were implanted with a collared short-stem femoral implant. Canal flare index (CFI), stem angle, absolute and relative cut heights and relative size were measured radiographically and used as independent variables. Biomechanical performance of the construct was evaluated using physiologic loading (loading) and supraphysiologic loading (failure) protocols.

RESULTS

 During loading protocols, compressive stiffness was influenced by absolute cut height (p = 0.018). During failure protocols, peak torque was influenced by CFI (p = 0.004) and craniocaudal relative size (p = 0.005). Peak load and torsional stiffness were not impacted by any of the radiographic variables (p > 0.05). Three of six femurs developed longitudinal fractures originating at the medial calcar at the time of failure.

CONCLUSION

 The biomechanical performance of the collared short-stem implant was positively impacted by preserving more of the femoral neck, having a higher CFI and using a smaller implant size relative to the femoral neck isthmus.

Complications with the Zurich Canine Total Hip Replacement System in an Initial Series of Cases Performed by a Single Surgeon

OBJECTIVE

 The aim of this study was to quantify the complications using the Zurich total hip replacement system in an initial series of cases performed by a single surgeon who had experience with other total hip replacement systems.

MATERIALS AND METHODS

 This was a retrospective study in which complications were classified as major if any treatment was needed or if the outcome was less than near-normal function. Complications that did not warrant treatment and that did not result in function that was inferior to near-normal were considered minor. Outcomes were assessed by radiographic review, physical examination, subjective gait evaluation or, in one case, by objective gait analysis. Bilateral total hip replacements were considered separate procedures.

RESULTS

 The first 21 procedures in 19 dogs performed by a single surgeon were included. The mean time to follow-up was 48 weeks (range: 8-120 weeks; standard deviation: 36 weeks). Two cases (of 21) experienced major complications including one dog with excess internal femoral rotation during weight bearing and one dog having luxation. One case (of 21) had a minor complication; femoral fracture in the presence of an intact bone plate that maintained alignment and healed without treatment.

CLINICAL SIGNIFICANCE

 A high rate of successful outcomes with few major complications can be obtained in the initial cases treated using the Zurich total hip replacement system for surgeons with prior experience with other total hip replacement systems.