Tibial plateau levelling osteotomy locking-compression plates for stabilisation of canine and feline ilial body fractures

Use of Locking Plates Fixed with Cortical Screws for Pelvic Fracture Repair in 20 Cats

OBJECTIVE

 The aim of this study is to describe the use of String of Pearls (SOP) plates for the surgical management of feline pelvic fractures, including surgical technique, proposed indications, complications, and outcomes in a cohort of cats.

STUDY DESIGN

 This study is a single-center retrospective clinical case series.

METHODS

 Medical records (2015-2019) of cats presenting for pelvic fractures (n = 33) were reviewed. Type of fracture, preoperative and postoperative imaging, and complications were retrospectively retrieved. Owners were contacted via questionnaire for medium- and long-term follow-up.

RESULTS

 A total of 20 cats met the inclusion criteria. Minor intraoperative complications were encountered in three patients. One patient suffered a major intraoperative complication. Five major complications were encountered postoperatively. These included two greater trochanter osteotomy fixation implant removal and three SOP plate removal. Full function was recovered in all patients according to the owners' assessment.

CLINICAL SIGNIFICANCE

 The use of SOP plates in feline pelvic fractures appears to yield a consistently good outcome with a very low incidence of canal narrowing and screw loosening. SOP plates are easy to contour and to apply along the entire pelvic length.

Preliminary study on a novel dedicated plate for iliac fractures in dogs

Introduction

The aim of this study was to describe and evaluate a novel plate designed specifically for the canine ilium using finite element methods. The cranial portion of the plate had an elliptical shape and contained nine screw holes. The caudal portion of the plate was triangular with three screw holes. Four and three screws were used at the cranial (screw 1 to 4) and caudal (screw 5 to 7) segment of the plate. Finite element models of the plate and canine pelvis were created. A load of 300 N was applied on the femur-hip joint contact area. Values of Von Mises Stress on the plate, screws and the maximum and minimum main stresses in the bone were used to capture the mechanical factors in this study.

Results

The novel implant had a plate stress of 51.9 megapascals (MPa) with higher stress in the dorsal part of the plate. Screws 2 and 4 showed similar stress values of 17.3 MPa. Screws 1 and 3 were the most loaded (51.9 MPa and 75 MPa, respectively). Screws 5, 6, and 7 showed similar dissipation and stress values (21.55 MPa). There was traction force in the dorsal region of the pubis and compression in the ventral part, with dissipation and values of 15.4 MPa and 23.9 MPa, respectively, acquiring balance between them.

Conclusion

The novel plate is potentially applicable and specifically suitable for iliac fractures in dogs. The screws distribution modeled proved itself strategical since the simulated stresses were evenly distributed throughout the implant construct.

Ex vivo comparison of lateral plate repairs of experimental oblique ilial fractures in cats

OBJECTIVE

To determine the biomechanical behavior of different plate systems used for oblique ilial fracture fixation in cats.

STUDY DESIGN

Ex vivo biomechanical study.

SAMPLE POPULATION

Fifty fresh-frozen feline hemipelvises.

METHODS

Standardized simple oblique ilial fractures were created and fixed via lateral plating, using different implant systems (10 fractures in each group) The systems were: (1) the Advanced Locking Plate System (ALPS-5); (2) the Advanced Locking Plate System (ALPS-6.5); (3) the Locking Compression Plate 2.0 (LCP); (4) the FIXIN 1.9-2.5 Series (FIXIN), and (5) the Dynamic Compression Plate 2.0 (DCP). Stepwise sinusoidal cyclic loading was applied until failure (10-mm displacement). The groups were compared with regard to construct stiffness and the number of cycles withstood before 1-, 2-, 5-, and 10-mm displacement.

RESULTS

Bending stiffness was lower in ALPS-5 than in other specimens (P < .05). The ALPS-6.5 specimens withstood more cycles (P < .05) before 2-, 5-, and 10-mm displacement than the ALPS-5 and DCP specimens . The LCP and FIXIN specimens endured more cycles than DCP specimens before displaying 5- and 10-mm displacement (P < .05). The ALPS-6.5, FIXIN, and LCP specimens endured higher loads before failure than the DCP specimens (P < .05). Screw loosening occurred in all nonlocking specimens, and bone slicing occurred in all locking specimens.

CONCLUSION

The DCP and ALPS-5 constructs are less resistant to cyclic loading. Failure in nonlocking specimens involved screw loosening. It involved bone slicing in locking specimens.

CLINICAL SIGNIFICANCE

Both the plate size and the plate-screw interface are key to lateral plating success in cases of feline ilial fractures. The use of locking plates reduces the risk of the screw loosening in such cases.

Comparison of Single versus Double Lateral Plating in Treatment of Feline Ilial Fractures Using Veterinary Cuttable Plates

OBJECTIVE

 The aim of this study was to compare the frequency of implant failure and the extent of pelvic canal narrowing associated with the fixation of ilial fractures in cats with a single veterinary cuttable plate (SLP) or double veterinary cuttable plates (DLP) applied to the lateral surface of the ilium.

STUDY DESIGN

 Radiographic evaluation of feline ilial fractures plated laterally using SLP or DLP. Pelvic canal narrowing directly postoperatively and at 6 weeks follow-up was objectively measured using the sacral index (SI). Radiographs were evaluated for implant failure and fracture healing.

RESULTS

 Seventy-seven cats satisfied the inclusion criteria. Twenty-nine fractures were treated with a SLP and 48 with DLP. Implant failure occurred significantly more (p = 0.001) in the SLP group (14/29) compared with the DLP group (6/48). Follow-up SI was significantly different between the two groups (p = 0.048, SLP median: 1.0 range: 0.83-2.4, DLP median: 0.98; range: 0.76-1.45). Median change in SI was -0.04 (range: -1.4-0.05) in the SLP group and 0.0 (range: -0.23-0.23) in the DLP group. This difference was significantly different (p = 0.031).

CONCLUSION

 DLP leads to significantly less implant failure and significantly less pelvic canal narrowing compared with SLP. This difference in pelvic canal narrowing was small and the clinical relevance remains unclear.

Short-term outcomes of 59 dogs treated for ilial body fractures with locking or non-locking plates

OBJECTIVE

To determine the influence of plating systems on the clinical outcomes in dogs treated for ilial fractures.

DESIGN

Retrospective study.

ANIMALS

Fifty-nine dogs (63 hemipelves).

METHODS

Radiographs and medical records of dogs with ilial fractures presented to Iowa State University between 2003 and 2019 were reviewed. After fracture reduction, fractures were fixed with a locking plate system (LPS) or non-locking plate system (NLS). Perioperative, long-term complications, and follow-up data were recorded. The frequency of implant failure and pelvic collapse were compared using a logistic and linear regression analysis, respectively. Where the univariate test was statistically significant, a multivariate analysis across categories was performed to identify statistically different categories.

RESULTS

LPS and NLS implants were used in 25/63 and 38/63 hemipelves, respectively. Median follow-up time was 8 weeks (3-624 weeks). Implant failure occurred in 18/63 (29%) of fracture repairs, consisting of 17 with NLS and 1 with LPS. Revision surgery was recommended in five cases of implant failure, all with NLS. The probability of implant failure was higher when fractures were fixed with NLS (p = .0056). All other variables evaluated did not seem to influence outcome measures.

CONCLUSION

The variable with the most influence on the outcomes of dogs treated for ilial fractures consisted of the fixation method (NLS vs. LPS). Fractures repaired with NLS were nearly 20 times more likely to fail than those repaired with LPS.

CLINICAL RELEVANCE

Surgeons should consider repairing ilial body fractures in dogs with LPS to reduce the risk of short-term implant failure.