Coxofemoral Arthroscopy and Total Hip Arthroplasty for Management of Intermediate Grade Fibrosarcoma in a Dog

Comparison of dorsal and medial arthroscopic approach to canine coxofemoral joint: a cadaveric study

BACKGROUND

Arthroscopic exploration of ventromedial part of canine coxofemoral joint is limited in conventional dorsal approach.

OBJECTIVES

We evaluated the efficacy of a medial arthroscopic approach to the coxofemoral joint of dogs by analyzing the joint visible area and performing a safety analysis.

METHODS

Arthroscopic approaches to the coxofemoral joint were made in five cadavers using a traditional (dorsal) and novel (medial) approach. Three observers scored the visible area of images and videos of the acetabulum and femur. A safety analysis was performed via dissection of the medial hind limb. The distance between neurovascular structures and arthroscopic portals was measured.

RESULTS

The acetabulum was more visible in the dorsal than in the medial approach, with mean visualization scores of 16 ± 0.00 and 11.83 ± 1.26, respectively. The medioventral side of the femur was significantly more visible in the medial than in the dorsal approach, with mean visualization scores of 3.9 ± 0.99 and 6.93 ± 0.58, respectively. Safety analysis confirmed the medial portal site was safe, provided that the surgeon has comprehensive knowledge of the joint. The minimum distance from the arthroscopic medial portals to the nearest neurovascular structures was 2.5 mm.

CONCLUSIONS

A medial arthroscopic approach to the canine coxofemoral joint has potential clinical application. Dorsal and medial approaches differ significantly and have distinct purposes. The medial approach is useful to access the ventromedial joint, making it an eligible diagnostic method for an arthroscopic evaluation of this area.

The nature of coxofemoral joint pathology across family Canidae

We evaluated coxofemoral joints from museum specimens of: Vulpes lagopus; Vulpes vulpes; Vulpes velox; Nyctereutes procyonoides; Urocyon cinereoargenteus; Aenocyon [Canis] dirus; Canis latrans; Canis lupus lupus; Canis lupus familiaris; C. l. familiaris × latrans; and Canis dingo. Acetabular components included: fossa; articular surface; medial and lateral articular margins; and periarticular surfaces. Acetabular components variably revealed: osteophyte-like features; varying appearance of articular margin rims (especially contour changes); rough bone surfaces (especially fossa and articular surface); and surface wear. Proximal femoral components included: articular surface; articular margin; periarticular surfaces; and joint capsule attachment. Femoral components variably revealed: rough bone surface; bone loss; articular margin osteophyte-like features; caudal post-developmental mineralized prominence; and enthesophytes along the joint capsule attachment. Non-metric multidimensional scaling was used to analyze right-left asymmetric relationships between observed traits, across taxa. Significantly different acetabular trait asymmetry involved only C. latrans-C. l. familiaris; V. vulpes-N. procyonoides, and U. cinereoargenteus-N. procyonoides. There were no significant lateralized differences in proximal femoral traits involving modern canids, ancient and modern C. l. familiaris, or modern vulpines. Thus, the observations were strongly bilateral. We hypothesized high similarity of traits across taxa. The data confirm the hypothesis and strongly suggest broad and deep morphological and mechanistic conservation that almost certainly pre-existed (at least) all modern canids. Further zoological studies are needed to evaluate phylogenic implications in greater detail.

Radiographic and Biomechanical Assessment of Three Implant Designs for Canine Cementless Total Hip Replacement

OBJECTIVE

 The aim of this study was to evaluate the relationship between radiographic fit/fill measurements and biomechanical performance of three canine cementless total hip implant designs using an in vitro biomechanical testing protocol that replicates compression and torsion.

STUDY DESIGN

 Eighteen (six/group) canine cadaveric femurs were implanted with one of three cementless total hip implant designs: (1) collarless, (2) collared or (3) lateral bolt stems. Femoral length, canal flare index (CFI), canal fill, stem fit, stem level and stem angle were measured as independent variables. Biomechanical performance was tested using physiological, non-destructive gait loading (loading protocols) and destructive testing (failure protocols).

RESULTS

 During loading protocols, compressive stiffness was influenced by stem level (p < 0.05) and torsional stiffness was influenced by stem level and CFI for collarless stems (p < 0.05). During failure protocols, peak load was influenced by mediolateral (ML) stem angle (p < 0.05) and CFI (p < 0.01) for collarless stems and CFI for lateral bolt stems (p < 0.05). Peak torque was influenced by ML stem angle, craniocaudal stem angle and CFI for collarless stems (p < 0.05) and average ML fill for collared stems (p < 0.05).

CONCLUSION

 Biomechanical performance of collarless stems in cementless hip arthroplasty is more impacted by radiographic fit/fill than lateral bolt and collared stems. As a result, collarless stems may be more dependent on preoperative fit and intraoperative precision.

Hemipelvic and proximal femoral limb salvage endoprosthesis with tendon ongrowth in a dog

OBJECTIVE

To report the clinical application of a hemipelvic and proximal femoral endoprosthesis for limb salvage.

STUDY DESIGN

Retrospective case report.

ANIMAL

One 5-year-old, neutered female, flat coated retriever with a malignant neoplasia of the left coxofemoral joint.

METHODS

An invasive soft tissue mass (histiocytic sarcoma) with bone lysis of the femoral head and acetabulum was noted on radiographs, computed tomography (CT), and MRI. Custom-designed hemipelvic and proximal femoral endoprostheses were produced from CT images and manufactured with hydroxyapatite coated surfaces to allow tissue integration. The proximal femoral implant allowed tendon ongrowth and muscle attachment. The pelvic implant was anchored to the ilium and ischium with screws, and the femoral implant was cemented. Chemotherapy consisted of lomustine (CCNU).

RESULTS

No evidence of implant loosening or local/thoracic metastases was noted on radiographs or CT at 6 weeks and at 3, 6, 9, and 12 months after surgery. A neurapraxia resolved 14 weeks postoperatively. Intensive rehabilitation was performed. At 12 months, activity was unrestricted with minimal residual lameness. The dog was euthanized at 14 months for metastatic disease.

CONCLUSION

Limb salvage with a hemipelvic and proximal femoral endoprosthesis resulted in limb function and survival for 14 months.

CLINICAL SIGNIFICANCE

Neoplasia involving the bones of the coxofemoral joint traditionally requires hemipelvic resection and pelvic limb amputation. This report provides evidence that limb salvage can result in satisfactory levels of activity.

Evaluation of a joint distractor to facilitate arthroscopy of the hip joint in dogs

OBJECTIVE

To evaluate the technical feasibility and efficacy of a hip joint distraction technique, any potential ligamentous damage linked to the procedure, and the effect of joint venting on the maximum distraction achieved.

METHODS

Twenty hip joints from 11 canine cadavers were evaluated radiographically by standard and stressed projections. Joint distraction was applied with loads from 40 up to 200 N, in 40 N increments, and fluoroscopic images were obtained at each load. At 200 N, a needle was inserted into the joint to achieve a venting effect, and the space was measured again. Standard and stressed radiographs were performed to evaluate potential laxity changes.

RESULTS

Distraction caused a significant increase in joint space at each load of distraction, although there were some variations. Joint venting produced a significant increase in joint space. A statistically significant difference in joint laxity evaluated radiographically before and after the procedure was recorded.

CLINICAL SIGNIFICANCE

Use of the distraction apparatus resulted in an increase in joint space. This could be useful for clinical situations where a larger joint space is required such as for arthroscopic procedures. However, loads in excess of 200 N may induce significant increases in joint laxity.

Determinants of passive hip range of motion in adult Greyhounds

OBJECTIVE

To determine the ranges of normal pelvic limb range of motion in adult Greyhound dogs, and to explore which factors influence hip range of motion in a population bred to meet the specific demands of racing. Design A cross-sectional study design.

METHOD

Thirty-two dogs (17 male and 15 female) 13 to 81 months old were randomly selected from a local pool of 160 Greyhounds. Goniometric measurements of hip, stifle and hock range of motion were recorded in triplicate. Signalment information collected included sex, weight and age of each Greyhound. The outcome factors for the study were range of hip flexion and hip extension. The theorised exposures, age, sex, weight, racing history and hock and stifle range of motion, were modelled against the outcome variables by linear regression analysis.

RESULTS

Male dogs were significantly heavier (P < 0.001) and older (P < 0.002) than female dogs. Mean hip flexion was 71.75 degrees and mean hip extension 128.10 degrees. The determinants of hip flexion were sex (P = 0.008) and range of stifle flexion (P = 0.002). Race training did not influence the range of hip flexion in the sample. Determinants of hip extension included range of stifle extension (P = 0.015), history of race training (P = 0.004) and hock flexion. The mean hip extension of raced Greyhounds was 134.95 degrees compared with 121.25 degrees for unraced Greyhounds (mean difference -13.70, 95% confidence interval -18.12, -9.29; P < 0.001).

CONCLUSIONS

This study has reported isolated pelvic limb joint range of motion in the racing Greyhound. Hip range of motion was affected by stifle range of motion, sex and race training. Dogs that had received race training had greater flexibility, possibly due to training having an active stretching role on muscles, tendons and other structures limiting the hip range of motion.