The management of cranial cruciate ligament injuries is one of the most common orthopedic challenges facing veterinarians. The injury was first described almost 80 years ago, and a repair technique was proposed in 1952 by Paatsama. Since then, many techniques have been described and utilized in veterinary patients. The techniques can roughly be categorized either as intra- or extra-capsular procedures. The former are typified by the under and over technique. Among the latter are the fibular head transposition, tibial plateau leveling osteotomy, tibial tuberosity advancement, and various fabellar suture techniques.
Paatsama's intra-capsular surgery was modified in 1979 when Arnoczky developed the over-the-top procedure. Variations by Hulse and later by Shires and Hulse have further refined this surgery. The original extracapsular repair was described by DeAngelis and Lau in 1970. Modifications were proposed by Flo and by Gambardella as well as by Krauss working with the Securos system. The various descriptions varied as to number and placement of the sutures as well as in the method of securing them. Some techniques place sutures on both medial and lateral aspects of the joint, and some place sutures through one or two holes in the tibia while others use the patellar tendon. The fibular head transposition (FHT) was introduced in 1985 by Smith with additional publications investigating the procedure published later. Finally, Slocum introduced his cranial wedge osteotomy and later the tibial plateau leveling osteotomy (TPLO). The TPLO was a patented procedure which therefore required surgeons to attend a training course if they desired to perform the surgery. Unfortunately, the course had an excessively long waiting list for most practitioners. This fostered some negative feelings among the veterinary community. Additionally, the expense associated with the course and equipment, and the difficulty of the procedure mad it less advisable for many veterinarians. The patent for the procedure has recently expired which may make the procedure more available. Similar procedures include tibial wedge osteotomies and tibial tuberosity advancement.
Given the plethora of surgical choices for managing cruciate ligament tears, it is not surprising that a great deal of controversy exists about which technique to use. Many veterinarians refer the cases to specialists who have their own opinions. Others veterinarians, however, may not have referral as a reasonable option, or may desire to perform the technique themselves. This session will attempt to address the needs of those veterinarians and offer suggestions. The best procedure for an individual patient will depend on many different factors.
Numerous manuscripts have been published describing and investigating the surgical correction of cranial cruciate ligament rupture. Some of the studies directly compare techniques, but none are ideal for a variety of reasons. Most studies only address a portion of the problem or rely on poor science. This has led to a great deal of speculation about the merits of the surgeries and has allowed various ideas and theories being accepted.
Despite the lack of ideal investigations, numerous comparisons can still be evaluated and will prove useful. Clinicians must be aware of the limitations of the studies and avoid making inappropriate conclusions. Smith compared FHT to an intra-articular fascial strip technique. The FHT was deemed to be superior. Unfortunately, the long-term evaluation was done using phone interviews. Additionally, the distribution of body weight between the two groups was uneven. In 1996, Chauvet et al evaluated the FHT in comparison to the lateral fabellar suture (LFS) and conservative treatment. The authors found that there was no difference in treatment groups in regard to lameness, and that all had arthritic progression. Owners expressed greater satisfaction with the LFS. Force plate evaluation in this study was only performed at recheck and results were compared between groups. Also in 1996, Jevens et al compared the LFS surgery to the under-and-over method. Although the LFS technique was superior, the dogs were experimental subjects not those with naturally occurring rupture. Other authors have reported results for individual procedures, but the lack of direct comparison makes conclusions difficult to draw. Most recently, Conzemius reported on comparison of LFS, fascial strip, and TPLO and he found no significant difference in the animals' performance.
As with many topics in veterinary medicine, clinicians performing surgery on cruciate injuries must make decisions based partially on personal preference, partially on literature, and partially on anecdotal reports. In this case, the various procedures have advantages and disadvantages.
The advantages to intra-articular techniques lie in the fact that they may recreate normal biomechanics better than other procedures and in the observation that the graft will revascularize to resemble ligamentous tissue. The biomechanical advantage has not been shown to correlate with decreased severity of arthritis or with higher performance. Additionally, the various intra-articular techniques are generally somewhat more challenging than a LFS.
The LFS is an easy, quick and inexpensive option. The procedure does not precisely recreate joint motion, and it often loosens with time. Regardless, LFS has always performed as well as other techniques in clinical studies. Recent evidence may suggest that with appropriate physical therapy these animals may even have as quick a return to weight-bearing as with a tibial plateau leveling osteotomy (TPLO).
This session will not discuss the TPLO or tibial tuberosity advancement (TTA) procedure, but a few comments are appropriate. As is the case to some extent with other techniques, the support for these surgeries is largely anecdotal. There have been no clinical studies that document better outcomes with TPLO or TTA after direct comparison with other surgeries. Despite this, the procedures have gained acclaim and popularity.
As is likely clear from the above discussion, there is no consensus on how to repair cranial cruciate ligament damage in the dog. Therefore, this session will include some guidelines and suggestions I believe are reasonable. Specifically, the focus will be on the practicality of performing LFS technique in practice. The type of suture material and details of the technique will be addressed. Some comments about physical therapy will also be made.