Ankle Osteoarthritis: Information & Specialists for the Treatment of Ankle Osteoarthritis

The ankle joint consists of three bones:

• Tibia
• Fibula
• Talus

The tibia and fibula form the ankle joint fork, which allows the talus to sit in a centered and precise position. The so-called talocrural joint controls the raising and lowering of the foot. Within the ankle joint fork, the talus performs gliding and slight rotational movements.

The articular surfaces of the tibia, fibula, and talus are covered with a thin but highly elastic layer of cartilage.

Osteoarthritis of the upper ankle joint destroys the articular cartilage. A previous injury (trauma) is usually considered the trigger for osteoarthritis. Less commonly, osteoarthritis of the upper ankle joint is caused by another underlying orthopedic condition, such as joint inflammation (arthritis).

Older people are more likely to suffer from joint wear and tear in the ankle, but younger people—especially active athletes—can also be affected.

A torn ligament often leads to chronic instability of the joint. Over time, this can cause wear and tear on the cartilage in the ankle joint and ultimately lead to the development of osteoarthritis in the ankle.

Injuries to the ankle joint can result in a fracture of the medial malleolus or the lower part of the fibula. Sometimes both the medial and lateral malleoli are affected by a fracture, often accompanied by cartilage damage.

High-impact sports or being overweight can also significantly strain the joint cartilage.

Typical symptoms of an ankle fracture include

• a swollen, painful ankle with bruising (hematoma) and
• limited range of motion.

In Germany, workers’ compensation insurance agencies report approximately 10,000 ankle fractures annually. 

Malalignments are often responsible for increased pressure on the ankle joint cartilage. Such malalignments can also develop after fractures, leading to premature wear of the cartilage and ultimately to osteoarthritis in this area. 

So-called primary ankle osteoarthritis, on the other hand, is less common than secondary ankle osteoarthritis. It does not result from pre-existing conditions or injuries, but occurs without any apparent cause. It is believed that genetically determined, insufficient cartilage formation plays a role. Compared to osteoarthritis of the hip or knee joints, however, it occurs rarely, as the cartilage of the ankle joint has a unique biochemical composition and significantly higher compressive strength. 

The stages of ankle osteoarthritis range from initial cartilage damage with mild pain to a severe form with significant limitation of movement and persistent symptoms.

Extensive cartilage damage in the ankle joint, in cases of advanced osteoarthritis, is characterized by painful restrictionof joint movement. Every step is painful. In advanced stages of ankle osteoarthritis, pain is present even at rest, which has a significant impact on the patient’s quality of life. As the disease progresses, weight-bearing causes swelling and inflammation, leading to severe pain in the ankle joint.

Alignment abnormalities and, sometimes, ligament instability are also frequently observed. X-raysand MRIs of this condition show the orthopedic surgeon the destruction of the joint, with a narrowed or obliterated joint space and bony spurs forming to provide support to the joint. This may then necessitate surgical intervention.

In the early stages of ankle osteoarthritis, arthroscopy can help slow the progression of the disease. During this procedure, problematic bony spurs on the tibia are removed, which can improve mobility and relieve pain. As osteoarthritis progresses, pain in the foot and ankle, as well as limitations in movement, increase significantly. In severe cases, this can even affect the degree of disability.

Initially, targeted pain management is often employed, such as medication, physical therapy, or injections. If these measures are no longer sufficient, surgical options include joint fusion (arthrodesis) or the implantation of an ankle joint prosthesis. Both procedures aim to reduce pain and improve the quality of life for those affected in the long term.

Ankle Fusion for Ankle Osteoarthritis

Ankle fusion (arthrodesis) can significantly reduce pain in most patients. Alongside joint replacement, ankle fusion is considered the treatment of choice. It is performed in many hospitals.

The video shows the surgical procedure for arthroscopic ankle fusion:

The technique for ankle arthrodesis has been further refined in recent years. The remaining cartilage on the damaged joint surfaces is removed along with the pathologically altered bone layer.

The tibia and talus are internally stabilized by inserting screws and/or an angle-stable plate. This allows them to heal together in a manner similar to that of a bone fracture. Any existing axial misalignments in the ankle joint are corrected and realigned by removing bone wedges of a specific size. This is an important prerequisite for being able to place the foot flat on the ground.

Ankle arthrodesis is generally well tolerated. It allows the patient to walk unobtrusively and smoothly without the need for special shoe modifications.

Ankle Replacement for Osteoarthritis

In most clinics, arthrodesis is still considered the gold standard procedure. Under the following circumstances, however, an ankle prosthesis is the better choice: 

• If both ankle joints are affected, or
• if the patient has high expectations regarding the preservation of mobility.

The prosthesis prevents overloading of the adjacent tarsal joints and protects them from secondary osteoarthritis.

Patients with inflammatory polyarthritis, in particular, benefit from an ankle replacement. They have usually already undergone several surgeries on their lower extremities. For them, an ankle replacement means preserving overall mobility and a positive change in gait.

Endoprosthetic replacement therefore offers advantages over arthrodesis, particularly in cases of inflammatory destruction of the upper ankle joint.

Based on their design, ankle joint endoprostheses can be classified into

• uniaxial prostheses,
• semi-coupled two-component prostheses (hinge principle),
• multiaxial two-component prostheses (“ball-and-socket principle”), and
• three-component prostheses.

Three-component prostheses with a mobile or fixed inlay (polyethylene insert) replace

• either only the central joint segment between the tibia and the talus, or
• also the inner and outer malleolar regions of the talus.

The metal components have a special coating. This allows bone to grow into them, making it possible to avoid cement fixation. Thanks to their highly advanced designs, these systems now cause only minimal wear and, as a result, significantly less cartilage damage. This significantly reduces the risk of loosening and the reoperation rate.

Which ankle prosthesis best reduces symptoms and promotes mobility?

The talocrural joint does not merely allow for simple hinge-like movement. During walking, various joint movements occur around multiple shifting axes:

• gliding,
• mild inversion and eversion, and
• rotation.

Uniaxial two-component prostheses based on a hinge joint principle therefore exhibited high loosening rates. The problem with multiaxial two-component prostheses lay in their often insufficient joint stabilization.

With the modern three-component prostheses mentioned above, the physiological axes of motion are mimicked much more effectively. In follow-up examinations, the three-component prostheses showed significantly better results than the older two-component prostheses. The complication and loosening rates were significantly lower, and the range of motion achieved was greater.

Cementless implantation of three-component prostheses also offers advantages in the event that explantation becomes necessary. Explantation refers to the subsequent removal of a prosthesis, for example, because it has become loose (replacement surgery). Less bone is lost during explantation. This allows for a prosthesis replacement or arthrodesis to be performed safely.

Biomechanical studies show that three-component prostheses exhibit normal rotational and tilt stability both inward and outward. Three-component prostheses currently provide the best assurance of the physiological range of motion in the ankle joint. This is supported by pressure and force measurements taken under the foot during gait.

The three-component ankle prosthesis is an effective treatment option for ankle osteoarthritis.