Treatment Options for Cranial Cruciate Ligament Rupture In Dog-A Literature Review

Cranial cruciate ligament (CrCL) breaks in dogs can be treated by surgical and non-surgical methods. Choice of the treatment method of cranial cruciate ligament rupture in dog continues to be a real problem for veterinarian clinicians. This topic has been the subject of many studies. Investigation of the speciality literature data concerning the surgical treatment options in the management of cranial cruciate ligament injuries) in dogs, remains, in the conditions of an informational avalanche, a present concern, The purpose of this study was to analyze additional evidence which have appeared in the literature in the period of 2006 January 2017 and which advocate with concrete evidences in the favour or disfavour of a particular method of dogs’ cranial cruciate ligament injuries treatment. Analysis of online searches using PubMed engine in 403 articles suggest that the data analyzed do not allow accurate comparisons between different treatment procedures of cranial cruciate ligament deficiency in dogs and did not show significant differences nor major changes when compared to previous reports (from 1963 to 2005). New long-term clinical studies must be designed and further biomechanical and kinematic analyses are required to determine the optimal technique, and whether these procedures are superior to other stabilization methods.


Introduction
Choice of the treatment method of cranial cruciate ligament (CrCL) rupture in dogs continues to be a real problem for veterinarian clinicians. This topic has been, since 1963 [1], the subject of many concerns and studies. CrCL breaks in dogs can be treated by surgical and non-surgical methods. The latest study investigating the speciality literature on surgical treatment options in the management of CrCL ruptures in dogs was published in 2005 [2] after an online bibliographic search through Medline, PubMed, Veterinary Information Network, and Commonwealth Agricultural Bureau Abstracts, with 240 sources being found and analyzed, and it ends with the conclusion "At this time, the application of evidence-based medicine in analyzing the current available evidence suggests that there is not a single surgical procedure that has enough data to recommend that it can consistently return dogs to normal function after CCL injury".
Referring only to the surgical procedures used to treat dogs' CrCL ruptures, a review from 2011 [3] was focused only on extracapsular procedures and shows that there is no data to allow recommendation of a specific technique being necessary "future studies should be directed toward outlining the virtues and inadequacies of the current techniques" and another study investigating the literature (444 paper works) with constant referring only on surgical procedures occurred in 2014 [4] conclude that tibial plateau levelling osteotomy (TPLO) is superior to the extra capsular lateral side suturing procedures, but there are insufficient data to properly assess other surgical methods. There are also several studies comparing the effectiveness of surgical and non-surgical therapeutic methods, the latest being dated in 2013 [5][6][7]. The purpose of this study was to analyze additional proof which have appeared lately in the speciality literature in the favour / disfavor of a particular method of CrCL breaks treatment in dog.

Materials and Methods
In January 2017, an online search was conducted, using three search engines: Google scholar (https://scholar.google.ro), PubMed -US National Library of Medicine National Institutes of Health (https://www.ncbi.nlm.nih.gov/pubmed) and Taylor & Francis Online (http://www.tandfonline.com). There have been used as basic search term "cranial cruciate ligament rupture in dog" preceded into three main additional insights by the terms "treatment", nonsurgical treatment", surgery treatment", last with the following secondary insights "lateral extracapsular stabilization treatment", "tibial plateau levelling osteotomy -TPLO", "tibial tuberosity advancement -TTA", "triple tibial osteotomy -TTO" and "Maquet". Filtering of the results was done using "most recent" and "best match" for PubMed engine, "article" for Google scholar and subject" and publication date" for Taylor & Francis Online. The results obtained by investigating PubMed were analyzed and classified according to the method proposed by Aragon and Budsberg, 2005 [2], after the evaluation method used: a) Force plate analysis, b) Subjective and objective evaluation by the clinician and 3 -subjective evaluation by the pet owner, being considered relevant in this order (1 -maximum and 3 -minimum).

Results and Discussion
Results of the bibliographic online introspection are shown in Table 1. The analysis of search results with PubMed engine reveals 403 articles (for the period 1963 -January 2017), respectively 391 after manual excluding of those in whose abstract no connection to CrCL was found. In the period 2006 -January 2017, 216 articles were found regarding CrCL in dog, data that reveals a near doubling of number of articles reviewed by Aragon and Budsberg 61] makes the inventory of the main reasons of intra-articular procedures low use: -auto grafts have inferior stiffness and strength compared with normal ligament; -allografts have the inconvenience of collection and storage; -synthetic materials caused intra-articular fibrosis, bone abrasion and chronic inflammatory response; which has limited their use in veterinary medicine.
Securing of the suture reveals the existence of three systems: a square knot (SQ), a slip knot (SL) and a crimp clamp (CR).
Existing data show no new information being maintained the recommendation [82] "that 27-kgt nylon leader line be secured with a SL, and 27-kgt nylon fishing line be secured with a SQ" as the "clamping the first throw of a square knot in monofilament nylon leader material who increases failure load by two percent and stiffness by 16%, and decreases elongation by 12%" [74] although there are studies showing that "crimping suture alters the biomechanical properties of the loop" [80]. Securing the suture through CR remains a superior method of knotting techniques [83,84] and the wave pattern crimp system is more efficient then the single crimp system [85]. Using tensioning sutures systems before applying a crimp clamp does not bring significant advantages over manual tightening [86].
Difficulties in various procedures' execution are reported to be the bone tunnels creation in TR and anchoring around the fabella in LSF and pLSF [87]. Evaluation of extra capsular therapeutic methods efficiency, although it is the subject of several studies [74,86,88]; Anderson et al. [83]; [89,90]; Guenego et al. [70]; [62,63,70]; Havig et al. [16,17] with mostly positive reports, show that many of these studies are subjective (level 2 and 3). Studies based on analysis of data obtained through force plate measurements show that peak vertical force was 93% and vertical impulse was 96% of normal values in the limbs of dogs that had extra-articular stabilization at six months following surgery [90], recorded differences being insignificant when compared to normal preoperative values in all studies which appeared before 2006 [88,89] and after [16,17].
Postoperative complications reported after the application of extraarticular stabilization techniques are between 4.2 and 17.4% [91]; Frey et al.
Proximal Tibial Osteotomy Techniques: Includes, tibial plateau levelling osteotomy-TPLO, combined tibial plateau levelling osteotomy and tibial tuberosity transposition (TPLO-TTT), tibial tuberosity advancement-TTA with the variants TTA-1, TTA-2 and TTA-rapid, triple tibial osteotomy -TTO and modified Maquet procedure-MMP. All procedures impart primarily change the biomechanics of the stifle and required specialized and custom equipments. The choice of source of this equipment depend on surgeons' preferences or/and their affiliation to certain product companies [92]. Recent assessments of the effectiveness of therapeutic methods of tibial osteotomy reveals unanimously that locomotor function of the limb with CrCL insufficiency can be improved using the techniques of tibial osteotomy [ [112], the majority of doctors preferring surgical approaches [113][114][115][116].

Conclusion
Currently available data does not allow accurate comparisons between different treatment procedures of cruciate cranial deficiency in dogs. New long-term clinical studies must design and further biomechanical and kinematic analyses are required to determine the optimal technique, and whether these procedures are superior to other stabilization methods.