Arthroscopy: State of the Art


  Kurt S. Schulz, DVM, MS Diplomate ACVS, Chief and Associate Professor Small Animal Orthopedics, University of California   Steve Petersen DVM, Diplomate ACVS Chief surgeon Veterinary Specialists of Nevada


The purpose of this session:

To understand the indications and capabilities of arthroscopy in the dog and cat

Introduction

The use of arthroscopy in the diagnosis and treatment of orthopedic diseases of small animals has grown tremendously in the past ten years.  Reasons for this growth may include improved small joint instrumentation, advances in applications to small animal orthopedic diseases, and increased client awareness and demand.  In spite of lack of strong documentation demonstrating the superiority of arthroscopic techniques over open arthrotomy, purchasing of arthroscopic instrumentation and popularity of small animal arthroscopy courses continue to grow.  The purpose of this session is to provide a brief introduction to small animal arthroscopy through its history, advantages and disadvantages, instrumentation, and current applications.   History of general arthroscopy and veterinary arthroscopy   Origins of arthroscopy can be traced back to the 19th century and the development of an instrument by Bozzini to examine the human bladder.  The lack of an adequate light source however, limited the usefulness of this tool.  The invention of the incandescent light bulb in the 1800's permitted the development of a practical cystoscope in Germany providing the beginnings of the field of endoscopy.    The application of endoscopy to human joints was pioneered by Dr. Takagi who, in an effort to accelerate the diagnosis of tuberculosis of the knee, used a cystoscope to examine the stifle joint.   His success in this field led him to develop the first arthroscope in the early 1900's.   

The first use of arthroscopy in veterinary surgery occurred in the horse in Europe and by

the mid 1980's the use of arthroscopy in equine surgery was becoming commonplace.  Today the use of arthroscopy in the diagnosis and treatment of equine orthopedic diseases is well accepted and routine.

The development of arthroscopy in small animal surgery has lagged behind that of the human and equine fields likely because of the previous unavailability of small joint instrumentation, the cost of the equipment, and skepticism regarding the practicality and efficacy.   The initial description of the use of an arthroscope in the dog was by Siemering who reported findings of 180 stifle arthroscopies and concluded that the instrumentation was useful in the diagnosis of diseases of the canine knee             Techniques in small animal arthroscopy were substantially advanced by works that reported on the technique of arthroscopy of the canine stifle, shoulder, and coxofemoral joint. The next substantial advancement in the field was based on the work of van Bree and van Ryssen who described additional techniques for therapeutic uses of arthroscopy and initiated the first instructional course in small animal arthroscopy.

Basics of arthroscopic equipment

Many veterinarians are familiar with endoscopy equipment in general based on other applications including gastroscopy and thoracoscopy.  Arthroscopy equipment is simply a modification of this equipment.  The major tools are:

  • Camera box
  • Light source
  • Monitor
  • Camera head
  • Light cables
  • Shaver
  • Arthroscopy tray
  • Fluid pump
  • Biopsy forceps
  • Micro-picks and mallet
  • 1.9 mm 30° scope
  • 2.7 mm 30° scope
  • Printer
  • Radiofrequency unit and tips
  • Cannulas

Current techniques in canine arthroscopy

Arthroscopy of the shoulder

Our understanding of the diseases of the shoulder and their treatment has grown tremendously in recent years due primarily to the development of techniques of shoulder ultrasound and arthroscopy and to a lesser degree MRI of the shoulder.  Our past list of differentials of shoulder diseases has been vastly expanded, as have the potential methods of treatment.

Current differentials for shoulder disease in dogs

  • OCD of the humeral head
  • OCD of the caudal glenoid
  • Biceps tenosynovitis
  • Biceps tear or avulsion
  • Supraspinatus Calicification
  • Supraspinatus tearing
  • Infraspinatus tearing
  • Supscapularis stretch or tea
  • Medial glenohumeral ligament stretch or tear  

Major modes of therapy for shoulder diseases

  • Tenotomy – arthroscopic or open
  • Fragment or flap removal arthroscopic
  • Tenodesis – open surgery
  • Microfracture or abrasion of cartilage lesions - arthroscopic
  • Radiofrequency shrinkage of stretched ligaments or joint capsule
  • Physical therapy

Arthroscopy of the elbow

Elbow dysplasia is the greatest cause of forelimb lameness in dogs.  Fortunately we have a much greater ability to diagnose and treat this widespread disease primarily because of arthroscopy.  The single greatest lesson from elbow arthroscopy is “for a forelimb lameness of unknown origin, arthroscopy of the elbow should be part of the diagnostic plan.”  The justification for this is the relatively high frequency of significant elbow arthritis in spite of normal radiographic findings.

Current differentials for elbow diseases:

  • Fragmented coronoid process
  • OCD
  • Elbow arthritis
  • Incomplete fusion of the condyle
  • Ununited anconeal process
  • Infection
  • Immune mediated joint disease

Current therapies for elbow diseases:

  • Arthroscopic fragment removal
  • Abrasion arthroplasty
  • Microfracture
  • Arthroscopic assisted fracture repair

Arthroscopy of the carpus

Arthroscopy of the carpus is not difficult to perform although there are not many applications.  Some of the diseases we have diagnosed and treated with arthroscopy include:

  • Joint infection
  • Chip fracture removal
  • Cartilage assessment

Arthroscopy of the hip

Arthroscopy of the hip joint has recently been shown to be much more sensitive to osteoarthritic changes than radiography.  Because of this it is playing an increasing role in decision making for treatment of juvenile hip dysplasia.  Arthroscopy is now used to determine if young dogs are suitable candidates for TPO procedures.

Arthroscopy of the stifle

Arthroscopy of the stifle is one of the more difficult procedures.  Once mastered, however, exploration and treatment of the stifle joint is relatively simple.  The major benefits of arthroscopy over open surgery are:

  • Minimization of pain
  • Minimization of contamination
  • Increased visualization of the meniscus

Arthroscopy is now routinely combined with other procedures for treatment of the stifle including TPLO.  The combination of arthroscopy and TPLO may represent the state of the art of canine cruciate disease treatment.

Other diseases of the stifle treated with arthroscopy:

  • OCD
  • Infectious arthritis
  • Meniscal injury
  • Patellar disease

Arthroscopy of the hock

Arthroscopy of the hock is not as simple as the carpus but can be performed with practice.  Applications of hock arthroscopy include:

  • OCD
  • Cartilage evaluation and treatment
  • Infectious arthritis