The effect of pelvic osteotomy plate type on axial rotation of the acetabular segment in the triple pelvic osteotomy

Triple pelvic osteotomy with a 12.5° and a 20° Slocum-type plate: A short-term prospective clinical pilot study in 38 dogs

OBJECTIVE

To determine whether using 12.5° Slocum-like triple pelvic osteotomy (TPO) plates would create sufficient femoral head coverage and lower the occurrence of overrotation compared with using 20° TPO plates in dogs with hip dysplasia.

STUDY DESIGN

Prospective clinical study.

SAMPLE POPULATION

Thirty-five dogs with hip dysplasia (38 hips).

METHODS

Nineteen hips were surgically treated with a custom-made Slocum-type 12.5° TPO plate, and these were matched to 19 hips surgically treated with a 20° commercial Slocum TPO plate. Hips were case matched according to size and breed. Ortolani sign, angles of subluxation and reduction, distraction index, and femoral head coverage (FHC) were compared between groups. Excessive coverage was defined as >80%.

RESULTS

In the 12.5° group, FHC was ≥50% in all hips, with mean FHC (67%), gain (37%), and excessive coverage (11%) all significantly less than in the 20° group (79%, 54%, and 42%, respectively).

CONCLUSION

The 12.5° plate produced sufficient FHC compared with the 20° plate, with fewer hips with excessive coverage.

CLINICAL SIGNIFICANCE

The 12.5° TPO plate may result in sufficient FHC with a lower occurrence of excessive coverage compared with 20° plates.

A structural numerical model for the optimization of double pelvic osteotomy in the early treatment of canine hip dysplasia

Background: Double pelvic osteotomy (DPO) planning is usually performed by hip palpation, and on radiographic images which give a poor representation of the complex three-dimensional manoeuvre required during surgery. Furthermore, bone strains which play a crucial role cannot be foreseen.

Objective: To support surgeons and designers with biomechanical guidelines through a virtual model that would provide bone stress and strain, required moments, and three-dimensional measurements.

Methods: A multibody numerical model for kinematic analyses has been coupled to a finite element model for stress/strain analysis on deformable bodies. The model was parametrized by the fixation plate angle, the iliac osteotomy angle, and the plate offset in ventro-dorsal direction. Model outputs were: acetabular ventro-version (VV) and lateralization (L), Norberg (NA) and dorsal acetabular rim (DAR) angles, the percentage of acetabular coverage (PC), the peak bone stress, and moments required to deform the pelvis.

Results: Over 150 combinations of cited parameters and their respective outcome were analysed. Curves reporting NA and PC versus VV were traced for the given patient. The optimal VV range in relation to NA and PC limits was established. The 25° DPO plate results were the most similar to 20° TPO. The output L grew for positive iliac osteotomy inclinations. The 15° DPO plate was critical in relation to DAR, while very large VV could lead to bone failure.

Clinical significance: Structural models can be a support to the study and optimization of DPO as they allow for foreseeing geometrical and structural outcomes of surgical choices.

ORCID iD

ALA: http://orcid.org/0000-0002-4877-3630

AV: http://orcid.org/0000-0003-2837-7822

CB: http://orcid.org/0000-0002-7065-2552

EZ: http://orcid.org/0000-0003-4121-6126

MT: http://orcid.org/0000-0002-5699-6009

Evaluation of an overlapping pubic and ischiatic osteotomy for the improvement of acetabular ventroversion in dogs: an ex vivo study

OBJECTIVES

To assess the potential of a new single-session surgical procedure, the overlapping pubic and ischiatic osteotomy (OPIO) for modification of bilateral hip conformation. We hypothesized that OPIO would be simple to perform with currently available surgical equipment, through a single surgical approach, with minimal potential morbidity, and that it would allow adequate simultaneous bilateral improvement of coxofemoral joint conformation in patients at risk of canine hip dysplasia.

METHODS

The OPIO procedure was performed in the pelves of five large breed canine cadavers. Computed tomography images of each cadaver were compared by measurement of the dorsal acetabular rim angle (DARA), acetabular angle (AA), dorso-ventral sacroiliac ratio (SR), and pubic inlet area before and after OPIO.

RESULTS

Coxofemoral joint conformation was improved after OPIO. Postoperative DARA was significantly decreased (mean: -5.09°) and AA was significantly increased (mean: 3.54°) after OPIO. The SR was not significantly different after OPIO, indicating minimal impact on the sacro-illiac joints by the procedure. Pubic inlet dimensions and area were significantly decreased after OPIO, but the overall effect on pelvic inlet area was clinically insignificant.

CLINICAL SIGNIFICANCE

An OPIO allows some improvement of coxofemoral joint conformation in canine cadavers.