34th Annual Scientific Meeting proceedings

Introduction
Cranial cruciate ligament disease (CrCLD) is one of the most common orthopedic conditions in the dog, with concurrent meniscal injury rates reported to be between 33.2% and 83% (Böttcher et al, 2010; Fitzpatrick and Solano, 2010; Fung et al, 2023; Hayes et al, 2010; Ralphs and Whitney, 2002; Ritzo et al, 2014; Thieman et al, 2006). Tibial plateau levelling osteotomy (TPLO) and cranial closing wedge ostectomy (CCWO) are widely applied in the surgical management of CrCLD, with the aim of achieving a tibial plateau angle of 5°. Despite achieving this aim, the risk of late meniscal injury persists, with reported rates of 2.1% to 13.8% (Fitzpatrick and Solano, 2010; Gatineau et al, 2011; Metelman et al, 1995; Thieman et al, 2006).

Concurrent medial meniscal lesions have traditionally been surgically treated via partial meniscectomy (Ertelt and Fehr, 2009; Thieman et al, 2006), while in the absence of overt meniscal injury, some authors advocate meniscal release in order to reduce the risk of late meniscal injury (Thieman et al, 2006). Experimental evidence exists to suggest that neither of these procedures are benign, with significantly altered stifle biomechanics after either caudal pole hemimeniscectomy or medial meniscal release (Kennedy et al, 2005; Pozzi et al, 2006; Pozzi et al, 2008; Pozzi, Kim, Lewis, 2010; Pozzi, Tonks, Ling, 2010; Thieman et al, 2010). Dogs undergoing TPLO with arthrotomy and meniscectomy have been reported to have a poorer outcome than dogs undergoing TPLO with arthrotomy where the menisci are found to be intact and are left in situ (Gatineau et al, 2011). In humans, the meniscus is recognised to be a significant contributor to normal knee joint biomechanics, with partial meniscectomy possibly accelerating the progression of secondary osteoarthritis (Feeley and Lau, 2018). Furthermore, degenerative meniscal injuries in humans are not always symptomatic (Englund et al, 2012) and even for symptomatic cases, non-surgical management is increasingly advocated as the first-line treatment over meniscectomy (Noorduyn et al, 2022; Rathleff et al, 2015).

It is widely accepted that arthrotomy is associated with a degree of morbidity, hence the drive for advanced imaging of the canine stifle (Tivers et al, 2008) or arthroscopic surgery (Hoelzler et al, 2004). One study demonstrated that a standard arthrotomy increases the progression of osteoarthritis in the stifle compared to a mini arthrotomy (Lineberger et al, 2005). Stifle arthroscopy is also not benign due to the requirement for distraction, infrapatellar fat pad resection and iatrogenic cartilage damage.

Because of the high incidence of concurrent medial meniscal injuries that routinely undergo surgical treatment alongside tibial osteotomy for CrCLD in dogs, it is challenging to attribute postoperative clinical improvement to treatment of the meniscus (Mccready and Ness, 2016). The need for routine meniscal evaluation and surgical treatment has been previously questioned (Bureau, 2017; Jandi and Schulman, 2007; Rutherford et al, 2012; Stauffer et al, 2006) and furthermore, prophylactic meniscal release has been suggested to be unnecessary when concurrent TPLO is performed (Gatineau et al, 2011; Pozzi et al, 2006). Bureau (2017) previously reported a low incidence of late postoperative lameness (6%) after TPLO without meniscal evaluation in a series of client-owned dogs. Only one dog (0.78%) had a persistent lameness following TPLO without exploration of the stifle which did not improve with non-surgical management. It is the author’s experience that the rate of late meniscal injury requiring surgery following initial tibial osteotomy without stifle inspection is low. In one institution the rate of late lameness benefiting from partial meniscectomy after initial TTA surgery without arthrotomy was 9.3% while it was 7.9% following TTA with arthrotomy. More recently, the rate of late lameness benefiting from partial meniscectomy after initial TPLO/CCWO surgery without arthrotomy was 5.5%, which falls well within the reported values for LMI following tibial osteotomy with stifle inspection.

Due to a lack of comparative studies the number needed to treat, number needed to harm and absolute risk reduction for stifle inspection at the time of tibial osteotomy for CCL disease is unknown. Why are we accepting ingrained dogma that seems to be resulting in large numbers of dogs undergoing unnecessary procedures. Given that this is the most commonly performed procedure in veterinary orthopaedics prospective comparative studies are urgently required.

References

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