There is essentially one bone above the ankle and 26 bones and as many joints below it that can affect alignment and functioning of the ankle joint. The nor- mal soft-tissue envelope around the ankle is thin, and because of possible antecedent trauma and initial sur- gical repairs, this envelope often is scarred and inelas- tic. These same issues, combined with the post-trau- matic period of immobilization, lack of physical ther- apy, chronic pain, and progressive periarticular bone formation, often lead to significant loss of ankle joint motion. In addition, progressive joint incongruency, destruction of the articular surfaces, and talar dislo- cation out of the ankle mortise may cause alteration of ankle joint mechanics, malalignment of the hind- foot, and destabilization of the ankle joint complex.
Careful investigation is, therefore, mandatory in or- der to identify the potential problems that may be en- countered during and after total ankle replacement.
2.1 Epidemiology
Many sports-related ankle injuries have been asso- ciated with biomechanical deficits such as static or dynamic malalignment of the skeleton [2, 6]. Hind- foot disorders, and especially ankle and hindfoot ar- thritis, have gained great epidemiological and so- cial-preventive importance in recent years. It has been stated that ankle and hindfoot arthritis will increase in the future decades, due to increasing in- cidence of trauma, involvement in sports activities, and longer life expectancy [1, 6, 9].
2.2 Characteristics of Ankle Arthritis
To understand the particular problems with total ankle replacement, it is first necessary to under-
Fig. 2.1. Primary osteoarthrosis.
Forty-nine-year-old male patient with primary osteoarthrosis: correct alignment and stability, dorsi-/plantar flexion 10° – 0° – 30°, typical radiological changes (see text) and cartilage wear. Weight-bearing X-rays (a, b). Intra- operative situs (c)
a b c
6 Chapter 2: Characteristics of the Diseased Ankle
Fig. 2.2. Severe post-traumatic osteoarthrosis.
Forty-three-year-old female patient with post-trauma- tic osteoarthrosis (a, b) 3.5 years after surgically treated ankle fracture: joint incongruency, varus malalign- ment, subchondral sclerosis and cyst formation, dor- si-/plantar flexion 10° – 0° – 20°. Notice the effect of loading in the lateral view (c). The CT scan evidences more articular changes and destruction than radio- logically expected, particularly in the anteromedial part of the ankle (d, e)
a b
c
d e
Fig. 2.3. Severe post-traumatic varus osteoarthrosis.
Sixty-one-year-old male patient with post-traumatic osteoarthrosis (a, b) after multiple ankle sprains, tenodesis, and fibula fracture, complaining of instability and pain when weight-bearing on the foot: anterolateral dis- location and varus malalignment of the talus in the ankle mortise (c–e), breakdown of the anteromedial tibial plafond, cavus deformity (f, dynamic pedobarography [Emed-System, Novel, Munich, Germany]), dorsi-/plantar flexion 5° – 0° – 30° (g, h)
a b
c d
e f
g h
stand the basic problem: namely, the pathology and varieties of ankle arthritis. Ankle arthritis includes primary and secondary arthritis (post-traumatic osteoarthritis and systemic arthritis [neuropathic arthropathy, inflammatory arthritis, and, rarely, infectious arthritis]). Osteoarthrosis is probably a better descriptive term for primary and post-trau- matic arthritis conditions, as it minimizes the in- flammatory component of this disorder.
2.2.1 Primary Osteoarthrosis
Primary osteoarthrosis is characterized by loss of joint cartilage and hypertrophy of bone. The exact mechanisms have not been defined, but subchondral bone injury and mechanical stress contribute to the
damage [9]. The radiographic hallmarks are joint- space narrowing (which correlates with loss of joint cartilage), osteophyte formation, subchondral bone cysts, and subchondral sclerosis. [5] There is usually an absence of juxta-articular osteoporosis in pri- mary osteoarthrosis (Fig. 2.1).
2.2.2 Post-Traumatic Osteoarthrosis
While hip and knee osteoarthrosis is predomi- nantly of degenerative etiology and seen in older patients, 80% of ankle arthritis is post-traumatic in origin [3], and occurs, therefore, mostly in youn- ger patients. Post-traumatic osteoarthrosis usual- ly occurs secondary to an intra-articular fracture of the weight-bearing ankle joint (Fig. 2.2) [4, 8, 10].
8 Chapter 2: Characteristics of the Diseased Ankle
Fig. 2.4. Bilateral rheumatoid arthritis of the ankle.
Forty-one-year-old female patient with bilateral rheumatoid arthritis of the ankle, right leg (a, b), left leg (c, d): valgus malalignment, bone cyst formation, concomitant talonavicular and subtalar arthritis
a b
c d
In addition to fractures, severe ligament lesions (chronic ankle instability) and dislocation injuries can also cause this entity (Fig. 2.3). In such cases, the soft-tissue envelope around the ankle is typi- cally involved, often becoming scarred and inelas- tic. Chronic pain and progressive periarticular formation of new bone often lead to significant loss of ankle joint motion. In addition to the changes seen in primary osteoarthrosis (that is, joint-space narrowing, osteophyte formation, subchondral bone cysts, and subchondral sclerosis), radio- graphically, post-traumatic osteoarthrosis also potentially includes joint incongruency, malalign- ment, and dislocation.
2.2.3 Systemic Arthritis
The category of systemic or inflammatory arthritis includes the various presentations of rheumatoid arthritis, mixed connective-tissue disorders, and synovial inflammatory conditions of unknown eti- ology [10]. Septic arthritis, psoriatic arthritis, arthritis associated with spondyloarthropathy, and Reiter’s syndrome are also in this category. Rheuma- toid arthritis is characterized by the formation of hyperplastic synovium that may destroy the under- lying articular cartilage, subchondral bone, and sup- portive musculotendinous and ligamentous tissues [7, 9]. Radiographically, inflammatory arthritis is characterized by symmetric joint-space narrowing, joint subluxation secondary to the imbalance of opposing muscle groups about a joint, juxta-articu- lar erosions, and osteopenia (Fig. 2.4) [9, 11].
2.3 Conclusions
In recent years, ankle arthritis has increased in frequency due to increased incidence of trauma during sports activities and increased life expect- ancy. The pathology of ankle arthritis involves cartilage degeneration, joint deformity, pain, and a decreased of range of motion that often leads to malalignment, limp, and gait abnormality. Ankle arthritis can be sub-classified into three groups:
primary osteoarthrosis, post-traumatic osteoar- throsis, and systemic arthritis. In relative terms, the post-traumatic group is the largest.
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