Introduction

Ankle joint arthroscopy has become an important tool for treatment of chronic and post-traumatic complaints of the ankle joint. After a clinical diagnosis has been made, this can be followed by arthroscopy to confirm diagnosis and subsequently treat the pathology.

Anterior problems that can be managed by means of routine ankle joint arthroscopy, include soft tissue and bony impingement, synovitis, and loose bodies or ossicles. More centrally-located complaints originating from an osteochondral defect or osteoarthritis can be diagnosed and treated arthroscopically, while posterior problems, such as a posterior impingement syndrome (os trigonum) or a flexor hallucis longus tendonitis can be treated by means of a two portal prone hindfoot approach. The routine procedure for anterior and central pathologies is carried out in the supine position as an out-patient procedure. In the fully dorsiflexed position, the anterior working area opens up and most ankle pathology is located or can be brought into this anterior working area. It is unnecessary to routinely perform distraction. There are however cases in which joint distraction eases access to the pathology and, therefore, improves execution of the surgical procedure. A simple resterilizable non-invasive distraction device gives reproducible results, and is easy to apply. The main advantage of the device is that the choice to perform distraction can be made at any moment during the arthroscopic procedure.

Two primary anterior portals are usually sufficient for routine arthroscopy. We routinely use the 4 mm arthroscope.

In patients without a definitive pre-operative diagnosis, there is only a very limited indication for diagnostic arthroscopy.

Anatomy

Superficial Anatomy

The ankle joint (or talocrural joint) is formed by the articular surfaces of the distal tibial and fibular epiphyses and the talus in its superior, lateral, and medial aspects. The morphology of these surfaces forms a hinge-type synovial joint with a single axis of movement that allows dorsiflexion (flexion) and plantar flexion (extension) of the ankle and foot in the sagittal plane. Because of this configuration and the fact that the ankle is a load-bearing joint, the interarticular space is narrow, making insertion of arthroscopic instruments between the articular surfaces difficult. Hence, articular distraction systems are used to perform complete arthroscopic inspection of the joint.

History & Physical Examination

There are a few important considerations in the diagnostic process. First we must differentiate between (sub-) acute and chronic injuries by means of obtaining a medical history, physical examination and standard X-rays. This process can be challenging, since patients with chronic complaints often have a sudden onset of symptoms after a ‘traumatic' event. In a substantial number of cases there is a time delay between the trauma and the visit to the clinician. It is therefore not always easy to differentiate between sub-acute, posttraumatic- and overuse injuries.

The onset of symptoms is important as well as the current symptoms. Together with the physical examination it is usually possible to come to a working hypothesis. This includes anterior ankle impingement (superficial anterior ankle pain, sportsrelated or post-trauma), osteochondral defect (deep ankle pain, often post-trauma), loose body (locking), synovitis (no trauma, temp?), osteoarthritis and instability (giving way).

Diagnostic Imaging

Introduction

Significant progress has been made both in de treatment of ankle and hindfoot pathology as well as in the field of imaging. Knowledge and understanding of the developments in both fields are important for proper treatment.

A routine X-ray of both ankles in the anteroposterior (AP) and lateral direction is the first step in de diagnostic workup. Degenerative changes caused by former accidents or by repetitive high load are often present in the ankle joint. This is especially true in athletes. A routine X-ray of the ankle and knee therefore should always be a weight-bearing view in the AP and lateral direction, comparing the involved joint to the contra-lateral unaffected joint.

Routine X-ray in ankle trauma

In most hospitals a routine X-ray of the ankle is made. The prevalence of an ankle fracture in patients with a painful swollen ankle that visit the First Aid Department of a Western hospital is up to 15%. Decisional rules have been proposed to minimize the number of routine X-rays. Applying the Ottawa ankle rules, results in a decline of routine X-rays to about 25%. When the Ottawa ankle rules are routinely applied, this means that a-priori chance of detecting an ankle fracture rises in the group of patients where X-rays are made. In spite of this, when dealing with (semi) professional athletes routine X-rays are made in the majority of cases, thereby neglecting the Ottawa ankle rules. Defensive medicine is probably the reason for this phenomenon.

Acute injuries

In an acute injury the first objective is usually to detect or rule out a fracture or avulsion. Other important questions are: is the cartilage involved, are there signs of soft tissue pathology as for instance ligament damage? An important question for the radiologist is whether the detected changes are old or new: is the bony fragment a fresh avulsion or is it an older ossicle? Are there signs of oedema, a partial rupture or is thickening of tissue part of an older fibrotic process?

Chronic injuries

Concerning chronic overuse injuries, it is important to differentiate between
1: articular- or periarticular problems,
2: pathology associated with long bones,
3: soft tissue injury.

Chronic (peri-) articular problems are usually posttraumatic. Knowledge about the initial trauma is important. Long bone imaging involves detection of osteomyelitis, deformities, stress fractures or tumors. Soft tissue injuries can be differentiated in muscle/tendon injuries and bursitis. Concerning muscle/tendon injuries imaging is directed towards detection of tendinopathy, a (partial) rupture, paratendinopathy, fibrosis or calcifications. The extent and location of the injury as well as the differentiation between old or fresh injuries is important.

Diagnostics in athletes

Athletes are a special type of patients. In general, an athlete is a highly motivated person that does not want to waste any time recovering. They are keen on resuming their sport activities as soon as possible. When working with athletes there is always time pressure. Moreover, they are surrounded by a group of caring people such as parents, coaches and sport physiotherapists. They all have their own interest, knowledge and influence on the patient. As a consequence, any delay in diagnosis is not accepted. Often these patients enter our outpatient department with an MRI that has already been made, while already having made an appointment for a subsequent second or third opinion. When dealing with professional athletes it is mandatory to provide services without any delay. This can interfere with services that need to be provided to the rest of the orthopaedic population. It is therefore important to have agreement on why, how and for which category of patients these services are applicable. Both the orthopedic department and the radiology department should feel comfortable with the situation.

Why is it interesting to be involved in the treatment of these athletes? The success or failure of our treatment can easily be monitored by the completeness and quickness of their return to the former level of competition. This direct feedback is to a far lesser level present in ordinarily patients. Seemingly small lesions can hinder a patient's performance. Knowledge of the sometimes sport specific lesions is important and can easily be overlooked or neglected. Some of these lesions are self limiting and with time the natural recovery is benign. However the time span of a professional athlete's career is short and consequently there is no time to wait for the natural recovery. On the other hand it is important to realize that posttraumatic injuries and degenerative changes are part of any (professional) sports career.

Additional diagnostics

There are several reasons why the orthopedic surgeon will ask for radiological diagnostics when dealing with athletes. The reasons can be divided as follow:

1. Routine X-ray;
2. X-ray to confirm a clinical diagnosis;
3. There is no firm clinical diagnosis and the orthopaedic surgeon is searching for a clue/pathology;
4. There is no firm clinical diagnosis and the orthopaedic surgeon is searching for confirmation of the negative clinical findings, i.e. medico legal reasons;
5. To explain the diagnosis to the patient;
6. Staging of disease in order to serve as a guideline for prognosis or to direct the treatment;
7. Preoperative planning.

There is a major difference between imaging techniques used for diagnosis and imaging techniques used for preoperative planning. Techniques serving the goal of preoperative planning require the images being easily interpretable by the orthopaedic surgeon. Since the orthopaedic surgeon is capable of reading plain X-rays, these routine or special X-rays such as oblique views, usually provide the most valuable information. Second best is a CT-scan. A spiral CT-scan with reconstruction in three directions provides images that can be interpreted by an orthopaedic surgeon. In combination with the routine standard X-rays it is possible to reconstruct the location and extent of the injury. This facilitates the surgical approach and the detection of the lesion during the surgery. For (peri-) articular and bony lesions MRI, bone scan or ultrasound are more difficult to interpret (and reconstruct), resulting in a more difficult guidance in preoperative planning.

Post-operative rehabilitation

The patient can be discharged the same day of surgery and weightbearing is allowed as tolerated. The patient is instructed to perform active dorsiflexion of the ankle to the neutral position (knee slightly bent). This exercise should be performed 2 or 3 days times per hour for the first days after surgery. The patient is instructed to elevate the foot when not walking to prevent edema. The dressing is removed 3 days post-operative. Normal walking without crutches at 4 - 5 days post surgery. Patients with limited range of motion are directed to a physiotherapist. Running can be started when range of motion is normal and in absence of swelling. This can on avarage be expected at 3 weeks post surgery. Sport resumption can on average be expected at 6 weeks post surgery. 

Recommended literature

Van Dijk CN, Fievez AWFM, Heijboer MP, et al. Arthroscopy of the ankle. Acta Orthop Scand 1993;64(suppl. 253):9.

Van Dijk CN, Scholte D. Arthoscopy of the Ankle Joint. Arthroscopy: The journal of Arthroscopic and Related Surgery, 1997;13(1):90-96.

Van Dijk, Verhagen RAW, Tol JL. Arthroscopy for problems after ankle fracture. J Bone Joint Surg (Br) 1997;79B(2):280-284.