Biomechanical Effects of Tibial Plateau Levelling Osteotomy on Joint Instability in Normal Canine Stifles: An In Vitro Study

Ex vivo biomechanical investigations of combined extra- and intracapsular stabilization in canines with cranial cruciate ligament deficiency

Intracapsular reconstruction (ICR) has long been recommended as a treatment for cranial cruciate ligament deficiency (CCLD) in dogs, but it has fallen out of favor due to its inferior long-term functional outcomes. These outcomes may be attributed to the poor stiffness and strength of the graft in the early period before ligamentization is completed. Additional placement of extracapsular sutures to mechanically protect the graft during the ligamentization process may be a viable method to address this problem. However, the biomechanical effect of this combined surgical approach remains unknown. This study aimed to evaluate the 3D kinematics of the CCLD stifle in dogs in response to ICR and combined extra- and intracapsular reconstruction (CEICR). Twelve hindlimbs were collected from nine cadavers of mature dogs. The limbs were tested using a custom-made testing apparatus that reproduces their sagittal plane kinematics during the stance phase. Four statuses of stifle joints were tested, namely, (a) cranial cruciate ligament (CCL) intact; (b) CCLD; (c) CCLD stifle stabilized by CEICR; and (d) CCLD stifle stabilized by ICR only. Three-dimensional stifle kinematics at the 5 instances of the stance phase were measured with an optoelectronic system. The results showed that ICR marginally corrects the increased adduction, internal rotation, and caudodistal stifle joint center displacement that occur as a result of CCLD. CEICR led to better restoration of the stifle kinematics, especially with respect to the internal rotation and cranial translation stabilities. Furthermore, CEICR only resulted in minor excessive restraints on other motion components. The findings indicated that the additional lateral fabellotibial suture offers immediate stability to the stifle, consequently lowering the risk of graft over-elongation in the short term postoperatively. Considering the propensity for the extracapsular suture to degrade over time, further in vivo studies are warranted to explore the long-term effects of the CEICR procedure.

Biomechanical effects of cranial closing wedge osteotomy on joint stability in normal canine stifles: an ex vivo study

BACKGROUND

Cranial closing wedge osteotomy (CCWO) is a functional stabilisation technique for cranial cruciate ligament (CrCL) ruptures. This biomechanical study aimed to evaluate the influence of CCWO on the stability of the stifle joint. Eighteen Beagle stifle joints were divided into two groups: control and CCWO. The stifle joints were analyzed using a six-degree-of-freedom robotic joint biomechanical testing system. The joints were subjected to 30 N in the craniocaudal (CrCd) drawer and proximal compression tests and 1 Nm in the internal-external (IE) rotation test. Each test was performed with an extension position, 135°, and 120° of joint angle.

RESULTS

The stifle joints were tested while the CrCLs were intact and then transected. In the drawer test, the CCWO procedure, CrCL transection, and stifle joint flexion increased CrCd displacement. The CCWO procedure and CrCL transection showed an interaction effect. In the compression test, the CCWO procedure decreased and CrCL transection and stifle joint flexion increased displacement. In the IE rotation test, CCWO, CrCL transection, and stifle joint flexion increased the range of motion.

CONCLUSIONS

CCWO was expected to provide stability against compressive force but does not contribute to stability in the drawer or rotational tests. In the CCWO-treated stifle joint, instability during the drawer test worsened with CrCL transection. In other words, performing the CCWO procedure when the CrCL function is present is desirable for stabilizing the stifle joint.

Vergleichende Langzeitergebnisse zwischen Tibial Plateau Leveling Osteotomy und Modified Maquet Procedure nach Ruptur des vorderen Kreuzbandes beim Hund

Gegenstand und Ziel Ziel dieser Studie ist es, die Modified Maquet Procedure (MMP) mit der Tibial Plateau Leveling Osteotomy (TPLO) anhand von Langzeitkontrollen über ein Jahr (∅ 3,15 Jahre) mittels klinischer Untersuchung, röntgenologischer Beurteilung der Arthroseprogression und Ganganalyse durch Laufbanduntersuchung zu vergleichen. Zusätzliches Ziel ist es, den Einfluss der Erfahrung der Chirurgen bei der TPLO-Technik zu überprüfen.

Material und Methoden Bei dieser klinischen Studie wurden 67 Kniegelenke von 50 Hunden verschiedener Rassen zwischen 20 und 40 Kilogramm Körpergewicht einbezogen, die mittels TPLO beziehungsweise MMP (n = 19) nach Ruptur des vorderen Kreuzbandes operiert wurden. Die TPLO-Gruppe unterteilte sich in eine Gruppe, welche von 2 erfahrenen Chirurgen (TPLO1, n = 25) operiert wurde und eine zweite Gruppe, die von mehreren Chirurgen unterschiedlicher Erfahrung (TPLO2, n = 23) versorgt wurden. Die Hunde wurden nach mindestens über einem Jahr (3,15 ± 1,21 Jahre) postoperativ orthopädisch, röntgenologisch und ganganalytisch uni- und bilateral getrennt untersucht. Zusätzlich wurden die Daten der Ganganalyse mit einer orthopädisch gesunden Kontrollgruppe verglichen.

Ergebnisse Bei der orthopädischen Untersuchung wurden keine signifikanten und klinisch relevanten Unterschiede zwischen den 3 Gruppen festgestellt.

Die Arthroseprogression zeigte in allen 3 OP-Gruppen ähnliche Werte, wobei die der TPLO2-Gruppe durchschnittlich pro Jahr gerechnet signifikant etwas geringer war als die der TPLO1- und der MMP-Gruppe.

Die ganganalytische Untersuchung im Schritt konnte vor allem im Vergleich mit der gesunden Kontrollgruppe signifikante Unterschiede bei bilateralen Rupturen für die Peak Vertical Force und den Vertical Impulse zeigen. Die Standphasendauer wies keine signifikanten Unterschiede auf. Im Trab konnten keine signifikanten Unterschiede zwischen den 3 OP-Gruppen festgestellt werden.

Schlussfolgerung Beide Operationstechniken erzielten in den 3 Gruppen bei den Langzeitkontrollen gute klinische, radiologische und ganganalytische Ergebnisse auch im Vergleich mit einer gesunden Kontrollgruppe.

Klinische Relevanz Die MMP kann als schnell durchführbare Alternative zur etablierten TPLO mit ebenfalls guten Ergebnissen beim Hund angesehen werden. Die Erfahrung des Chirurgen scheint keinen Einfluss auf das Ergebnis zu haben.

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°.