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Introduction and Instrumentation

1.1 Introduction

Arthroscopy is the most significant advance in small animal orthopedics that has occurred during my 50?years of professional lifetime.

Arthroscopy provides more information about intra-articular pathology than any other diagnostic technique. The most important advantages of arthroscopy are visual access to more joint area, magnification produced by the telescopes and video systems, excellent illumination, and a clear visual field when continuous irrigation is employed. Arthroscopy is also minimally invasive, reduces trauma, shortens operative times, and decreases recovery times. The small sizes of telescopes available today allow placement into the deepest parts of joints and combined with angulation of the field of view, 30° for most arthroscopes, provide visual access to more area of joints than can be achieved with open surgery. Arthroscopes magnify intra-articular structures allowing visualization of anatomical details and pathologic changes that are beyond the resolution of radiographs, CT, MRI, or what can be seen with open surgery (Video 1.1). Submacroscopic lesions that elude us with open surgical exploration can be easily seen with arthroscopy. High-intensity lighting is passed directly through the arthroscope providing perfect illumination of everything in the field of view of the telescope. Irrigation employed with arthroscopy maintains a clear field of view by continuously flushing blood and debris away from the end of the telescope. This is all done with minimally invasive technique and far less tissue trauma than with an arthrotomy. Speed is not the most important criteria or the most important advantage of arthroscopy over open arthrotomy, but for the experienced arthroscopic surgeon, anesthesia and procedure times are significantly shorter than with conventional open surgery. Postoperative recovery after arthroscopy is also much faster than following an open arthrotomy. This time comparison is an important advantage of arthroscopy. Most dogs recover to their preoperative status of lameness and pain within a few hours after arthroscopy. Many dogs are better than their preoperative level of function by the time they are released from the hospital on the day after arthroscopy. Arthroscopy is commonly performed as an outpatient procedure with a release on the same day as surgery. Activity restriction is not needed for portal site healing. The time required for healing of intra-articular structures after arthroscopy for conditions such as OCD and medial coronoid process disease (MCPD) has not been studied or effectively compared with healing after open surgery.

There are few disadvantages of arthroscopy. The most significant disadvantage is that arthroscopy is the most difficult of all endoscopies to learn. Arthroscopy's technical difficulty with its long slow learning process for both diagnostic applications and for performing corrective surgical procedures makes it a challenge to gain proficiency. Arthroscopy requires considerable practice, patience, and persistence to master. Reasons for arthroscopy's difficulty are related to the small space involved, confinement by rigid bony structures, and the anatomic complexity of some joints such as the stifle. Even with its difficulties, developing proficiency with arthroscopy is within the grasp of most who are willing to make the effort and put in the time to learn. Expense of instrumentation is a relative disadvantage as the cost of the equipment and instrumentation for arthroscopy is significant but is no more than other sophisticated instrumentation used in small animal practice today. The limitation of small patient size is shrinking as instrument size decreases and as our skill level and experience increase.

Arthroscopy is indicated whenever there is a history, physical findings, imaging changes, or laboratory result suggestive of joint disease. A history of lameness, stiffness, difficulty or reluctance to get up, reluctance to go up or downstairs, reluctance to get up and down off the couch or the favorite chair, and inability to get in and out of the car or truck; combined with joint pain, swelling or thickening, crepitus, reduced range of joint motion, or joint instability on physical examination are definite reasons to perform arthroscopy. Radiographic, CT, MRI, or ultrasound abnormalities of increased joint fluid or joint capsule thickening, periarticular osteophytes, periarticular sclerosis, OCD lesions, ununited anconeal processes, ununited caudal glenoid ossification center, intra-articular fractures or chips, periarticular bone lysis, tendon and ligament abnormalities, or any other changes involving a joint are also indications for arthroscopy. Normal radiographic, CT, MRI, or ultrasound findings do not preclude arthroscopy as a diagnostic technique if history and physical findings point to joint involvement. Arthroscopy is indicated whenever we need more information about a joint than can be obtained with any less invasive technique.

Arthroscopy is most commonly performed in the shoulder, elbow, and stifle in dogs. Arthroscopy is less commonly performed on the radiocarpal, hip, and tibiotarsal joints. Arthroscopy is easier to perform in large dogs but has been done effectively in dogs as small as seven pounds. Arthroscopy has also been performed in the shoulder, elbow, and stifle of cats but its use is largely unexplored in this species. The same positioning, procedures, techniques, and portals that are used in dogs are used for cats.

Conditions that have been diagnosed with arthroscopy (Table 1.1) include osteochondritis dissecans (OCD) of the shoulder, stifle, elbow, and tibiotarsal joints (Van Bree and Van Ryssen 1998); partial and complete cranial and caudal cruciate ligament ruptures; meniscal injuries; medial coronoid processes disease (MCPD); ununited caudal glenoid ossification center (UCGOC), ununited anconeal process (UAP), ununited supraglenoid tubercle, degenerative joint disease (DJD); intra-articular fractures; immune-mediated arthritis; synovitis; partial or complete bicipital tendon rupture; injury to other intra-articular soft tissues of the shoulder, soft tissue injury of intra-articular structures of the elbow, radiocarpal, stifle, and hip joints; septic arthritis; and neoplasia. Arthroscopic assessment of femoral head and acetabular articular cartilage condition in young dysplastic dogs have been used for case selection and to predict results with pelvic osteotomy surgery. Cartilage injury or chondromalacia secondary to instability, deformity, or inflammatory processes is more easily identified and the extent of damage scored more accurately than with open surgery.

Table 1.1 Diagnoses with arthroscopy.

Operative procedures currently being performed with arthroscopy (Table 1.2) include removal of OCD cartilage flaps and debridement of the cartilage defects in the shoulder, elbow, stifle, and tibiotarsal joints (Bertrand et al. 1997; Bilmont et al. 2018; Cook et al. 2001; Gielen et al. 2002; McCarthy 1999; Miller and Beale 2008; Olivieri et al. 2007; Person 1989; Rochat 2001; Van Bree and Van Ryssen 1998); coronoid process fragment removal (McCarthy 1999; Rochat 2001) and coronoid process revision or subtotal coronoidectomy (McCarthy 1999), free joint body (arthrolith) removal (Smith et al. 2012), bicipital tendon transection (Bergenhuyzen et al. 2010; Cook et al. 2005; Rochat 2001), carpal chip removal (McCarthy 2005), partial and total meniscectomy (Ertelt and Fehr 2009; Ridge 2006; Ritzo et al. 2014; Rochat 2001), cruciate ligament...