Accuracy of three pre- and intra-operative measurement techniques for osteotomy positioning in the tibial plateau levelling procedure

Cadaveric comparison of two techniques for intraoperative placement of tibial plateau levelling osteotomies in dogs

BACKGROUND

Both tibial tuberosity fractures and deviation from the planned postoperative tibial plateau angle have been associated with poor centring of tibial plateau levelling osteotomies (TPLOs). The aim of this cadaveric study was to compare two techniques for centring the osteotomy and preserving the tibial tuberosity width (TTW).

METHODS

Stifle radiographs were obtained from 20 limbs of 10 dogs. TPLO was planned on each stifle, and a two-wire technique (TWT) and a technique using the medial collateral ligament (MCL) as an intraoperative landmark were planned. The techniques were executed and marked with radiopaque pins. Further radiographs were obtained and analysed.

RESULTS

On average, TWT resulted in a 20.4% increase in TTW and medial collateral ligament technique (MCLT) resulted in a 13.4% decrease. Expressed as a percentage of the radial saw size, the average error in the centring of the osteotomy arising from the TWT was 13.4% and that from the MCLT was 14.2%.

LIMITATIONS

This study had a small sample size and involved a single surgeon.

CONCLUSION

Neither technique reliably identified the desired centre of the osteotomy, and both had a similar magnitude of error. MCLT resulted in reduced TTW, while TWT resulted in increased TTW. A reduced TTW has been associated with an increased risk of tibial tuberosity fracture, so MCLT is not recommended for clinical use.

Impacts of tibial plateau levelling osteotomy on the tibial insertion of the medial collateral ligament of the canine stifle joint - A cadaveric study

OBJECTIVE

The aim of this study was to assess the potential consequences of tibial plateau levelling osteotomy (TPLO) for the medial collateral ligament (MCL) tibial insertion (TI) with a particular focus on the effects of the TPLO planning technique and of the size of saw blade.

STUDY DESIGN

Eighty-six stifle joints were collected from 43 canine cadavers and dissected free of soft tissue to expose the MCL. The MCL insertion sites were first identified with Chinese ink on intact stifle joints, and then marked with radio-opaque barium sulfate after removal of the MCL. Mediolateral radiographs were made of each marked stifle joint and used for TPLO digital planning. For each stifle, planning the TPLO was performed by centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia in group 1, and at the top of the intercondylar tubercles in group 2. Whenever possible, two saw blade sizes were tested in each group. Measurements were taken after TPLO simulation to assess how the procedure would alter the MCL TI.

RESULTS

In group 1, the integrity of the MCL TI was affected by the TPLO planning in 87.2% of the cases with the small saw blade and in 59.3% of the cases with the large blade, and in group 2, in 94.2% of the cases with the small and 77.9% with the large saw blade. In group 1, the osteotomy line was located above the TI, completely severing the MCL in four cases versus in 11 cases in group 2, while severing occurred in 14/15 cases with the small saw blade.

CONCLUSION

During TPLO, the osteotomy line transected the MCL TI in the majority of dogs. Centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia and using the largest saw size that preserves tibial tuberosity and patellar tendon insertion seems to be the best way to preserve the MCL TI as much as possible. Further research is needed to evaluate the clinical impact of MCL TI transection.

Comparison of tibial anatomical-mechanical axis angles and patellar positions between tibial plateau levelling osteotomy (TPLO) and modified cranial closing wedge osteotomy (AMA-based CCWO) for the treatment of cranial cruciate ligament disease in large dogs with tibial plateau slopes greater than 30° and clinically normal Labradors retrievers

Background

The objective of this study was to evaluate tibial anatomical-mechanical axis angles (AMA-angles) and proximodistal and craniocaudal patellar positions following tibial plateau levelling osteotomy (TPLO) and AMA-based modified cranial closing wedge osteotomy (CCWO) in large dogs with tibial plateau angle (TPA) > 30°, to compare these postoperative positions with those of a control group of healthy normal dogs, and to assess which procedure yields postoperative morphology of the tibiae and stifles that is most consistent with that of the unaffected group. This study also investigated whether the occurrence of patellar ligament thickening (PLT), which is commonly observed 2 months postoperatively after TPLO, is associated with misplacement of the osteotomy. A total of 120 dogs weighing more than 20 kg, 40 of which were control animals, were enrolled in this retrospective study. Stifles were radiographically evaluated preoperatively and postoperatively on the side with CCLR and on the healthy contralateral side and compared with clinically normal stifles. PLT was reassessed after 2 months.

Results

Significant decreases in median patellar height ratio were found after both procedures (TPLO 0.24 (0.05–0.8); CCWO 0.22 (0.05–0.4)). The postoperative craniocaudal patellar position and the median AMA angle differed significantly among the groups (P = 0.000) (TPLO 87.5% caudal to the AA and 3.12° (0.76–6.98°); CCWO 100% cranial to the AA and 0° (− 1.34–0.65°); control group 5% caudal to the AA and 0.99° (0–3.39°)).

At 8 weeks, PLT grade differed significantly in the two operated groups (P = 0.000) (TPLO 40% 0–2, 20% 2–4, 40% > 4; CCWO 98.8% 0).

Conclusions

TPLO and AMA-based CCWO are associated with significant decreases in patellar height; however, the PLT results 2 months postoperatively differed between the two groups; the decrease in patellar height and PLT were independent of osteotomy position in the TPLO group. Compared to TPLO, CCWO results in reduced postoperative AMA angles and craniocaudal patellar positions that more closely resemble those of unaffected dogs, suggesting that the CCWO procedure allows us to better correct the caudal bowing of the proximal tibia that is often associated with deficient stifles in large dogs with TPA > 30°.

Influence of fixation systems on complications after tibial plateau leveling osteotomy in dogs greater than 45.4 kilograms (100 lb)

OBJECTIVE

To determine the influence of 3 fixation systems on complications rate after tibial plateau leveling osteotomy (TPLO) in dogs >45.4 kg.

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

Dogs (N = 287, 342 stifles) >45.4 kg with cranial cruciate ligament tear treated with TPLO.

METHODS

The medical records of dogs treated with TPLO were reviewed for fixation and postoperative complications, with a follow-up of at least 6 weeks. A random effects logistic regression model was used to evaluate the association between the type of TPLO fixation system and complications.

RESULTS

The fixation systems included a 3.5-mm broad TPLO plate alone (8P; 78.4%), a 3.5-mm broad TPLO plate with SOP (String of Pearls) plate (8AP; 14.9%), and a 3.5-mm standard TPLO plate (6P; 6.7%). Among the included stifles, 214 (62.6%) fixation systems were classified as locking, and 128 (37.4%) were classified as nonlocking. The fixation system was predictive of complications. The 8P had the lowest odds ratio for complication among the 3 fixation systems. Odds of developing complications were higher with the 8AP fixation system than with the 8P fixation system. Locking fixation eliminated the association between weight and complication rate.

CONCLUSION

Fixation of a TPLO with the 8AP increased the risk of complications compared with the 8P in this population of large dogs.

CLINICAL SIGNIFICANCE

Locking fixation of TPLO with a 3.5-mm broad TPLO plate alone should be considered in large dogs because it may reduce complications.

A novel jig arm to measure tibial plateau angle during tibial plateau leveling osteotomy

OBJECTIVE

To determine the ability of a novel device attached to the proximal tibial plateau leveling osteotomy (TPLO) jig pin to accurately predict intraoperative change in tibial plateau angle (TPA).

STUDY DESIGN

In vitro cadaveric study.

SAMPLE POPULATION

Left hindlimbs of adult dogs (n = 9).

METHODS

A modified Slocum tibial plateau leveling (TPL) jig with the Rotational Osteotomy Measuring Arm (ROMA) was placed on the tibia and a radial TPLO osteotomy was performed. Based on preoperative radiographic TPA measurements, the proximal segment was rotated using the traditional method of marking points on the osteotomy a specified distance apart. After rotation, the predicted TPA was recorded based on the ROMA. Postoperative TPA was measured on radiographs. The ability of the ROMA to predict postoperative TPA was compared to that of the traditional method.

RESULTS

The average final TPA achieved with the traditional method was 6.4° (range, 3.0-10.0°). The ROMA predicted a final TPA of 5.8° (range, 3.8-10.1°). No significant difference was found between the TPA predicted based on the traditional method and ROMA method.

CONCLUSION

The ROMA may be an alternative to the traditional method of measuring proximal segment rotation during TPLO procedure.

CLINICAL RELEVANCE

Performing a TPLO with the ROMA may accurately predict the postoperative TPA while eliminating the need for measuring chord length, making reference marks, or referencing TPA charts for various osteotomy blade sizes.

Evaluation of a new method to determine the tibial tuberosity advancement distance required to reduce the patellar tendon-tibial plateau angle to 90° with the modified Maquet technique in dogs

OBJECTIVE To assess use of a new radiographic method to determine the distance by which the tibial tuberosity should be advanced to reduce the patellar tendon-tibial plateau angle (PTA) to 90° by means of the modified Maquet technique (MMT) in dogs. SAMPLE 24 pelvic limbs from 12 adult medium-sized to large-breed canine cadavers. PROCEDURES Radiographs of stifle joints at 135° extension in true lateral position were used to determine tibial tuberosity advancement distances for use in the MMT. A method was devised to incorporate the planned osteotomy axis; distal patellar translations of 0, 3, 5, or 10 mm; and advancement cage implant application level along the osteotomy site in advancement planning measurements. Concordance correlation coefficients (CCCs) were calculated to compare these adjusted advancement measurements with true advancement measurements obtained for the same joints in another study after treatment by MMT. Intraobserver, interobserver, and total agreement for selected measurements were determined by assessment of CCCs for results obtained by 3 blinded observers. RESULTS Agreement between true advancement measurements and measurements obtained with osteotomy axis and cage position method calculations that incorporated a 5-mm distal patellar translation distance was excellent (CCC, 0.96). Intraobserver and interobserver agreements for the planning measurements evaluated were good to excellent (CCC, 0.83 to 0.96). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the osteotomy axis and cage position method incorporating a 5-mm distal patellar translation distance has the potential to improve success rates for achieving a PTA of 90° in medium-sized to large-breed dogs undergoing MMT for treatment of cranial cruciate ligament rupture. Further research is warranted.

Sagittal accuracy of tibial osteotomy position during in vivo tibial plateau levelling osteotomy performed without an alignment jig and cutting guide

OBJECTIVES

To assess the accuracy of tibial osteotomy location for tibial plateau levelling osteotomy (TPLO) in the sagittal plane and its effect on the postoperative tibial plateau angle (TPA), when performed without an alignment jig and saw guide. Also, to document the improvement gained with experience.

METHODS

Medical records and stifle radiographs of dogs undergoing TPLO, without the use of an alignment jig and saw guide, by one surgeon were reviewed (2010-2014). Postoperative radiographs were reviewed to record the distance and direction of eccentricity. Postoperative TPA was also recorded.

RESULTS

In a series of 401 TPLO procedures, 231 met the inclusion criteria. The absolute distance of eccentricity (DOE) for all dogs was 3.0 ± 1.6 mm. When evaluating surgical experience, the DOE for the final 77 cases (2.72 ± 1.43 mm), the middle 77 cases (3.18 ± 1.49 mm), and the first 77 cases (3.24 ± 1.7 mm) were not significantly different (p = 0.07157). There was a very weak correlation between DOE and postoperative TPA (R = 0.029).

CLINICAL SIGNIFICANCE

The location of the tibial osteotomy when performing TPLO without an alignment jig and saw guide compared favourably with previously documented use of an alignment jig and saw guide. Whilst the location of the tibial osteotomy has a theoretical impact on the postoperative TPA, other factors appear to be of greater importance. Surgeon experience did not result in significant improvement in accuracy up to 231 procedures.

Tibial plateau levelling osteotomy in eleven cats with cranial cruciate ligament rupture

OBJECTIVE

To report the surgical procedure, intra- and postoperative complications, and short-term follow-up of tibial plateau levelling osteotomy (TPLO) in feline patients with cranial cruciate ligament (CrCL) rupture using a 2.0 or 2.4 mm Synthes^® TPLO plate.

STUDY DESIGN

Prospective study.

MATERIAL AND METHODS

Eleven cats with a CrCL rupture were included in the study. Inspection of intra-articular structures was carried out via arthroscopy or arthrotomy. Each patient was re-examined one and 10 days after surgery. Orthopaedic examination and follow-up radiographs were obtained four to 12 weeks postoperatively.

RESULTS

Two meniscopathies and one partial CrCL rupture were detected. Minor intra-operative complications occurred in five cats (suboptimal positioning of the plate [n = 3], proximal fibular fracture [n = 1], a visible osteotomy gap [n = 1]). Postoperatively, minor complications were detected in three cats (mild patellar desmitis [n = 2], superficial wound infection [n = 1]). No additional surgical reintervention, graded as major complication, was necessary. Four to eight weeks postoperatively, all cats showed no to mild intermittent lameness. Complete bone union was apparent within four to 12 weeks. Owners reported a high level of comfort and mobility during the last follow-up.

CONCLUSION

The preliminary results of this study support the use of TPLO in cats, but larger case numbers are needed to evaluate its practicability, as well as long-term outcome (>1 year), especially evaluating the development and the clinical relevance of osteoarthritis.