One of the most common skeletal diseases associated with the wrist joint is rheu- matoid arthritis (RA) [10,11]. The disease affects mostly synovial joints, resulting in considerable pain, loss of function and eventual deformity as shown in Fig.3.1. It is a life-long condition, and the disease activity might change over time. Rheu- matoid arthritis is a chronic, systemic, inflammatory disease that results from an autoimmune disorder causing the damage of the joint [12, 13]. Swelling and inflammation of the joint are as a result of lymphocytes effect in the synovium, leads to mutilation of the joint. RA as a symmetrical disease is normally attacks Fig. 3.1 Patient affected by
rheumatoid arthritis with severe dislocation of both wrists [10]
26 3 The Wrist Joint Affected by Rheumatoid Arthritis
both sides of the limb (Fig.3.2). It can either be the same joint in both limbs or different joints of the same limb. For instance, patient with RA in the wrist has the same symptoms in the fingers of the same hand.
In conjunction with the pathomechanics of the RA, there are cascade of events behind it. The disease process commences by mainly affecting the soft tissues including the adjacent articular cartilage (chondrolysis) then followed by the hard tissues (bone resorption), thus resulting in severe deformities [12,13] of the joint.
Fig. 3.2 A posterior photograph of patient with rheumatoid arthritis hands (a), note axial deviation of the wrist and clearer observed as seen in X-ray of the right (b) and left (c) wrist [13]
3.2 Rheumatoid Arthritis 27
To efficiently examine the severity of the RA deformities, previous reports have introduced several classifications according to their own reliable approaches.
Larsen et al. classification used radiologic changes for scoring system with the basis of 5 grades, in which the degree of joint and cartilage destructions used as the primary indicators (Table3.1) [12,14]. Combination between radiologic findings and therapeutic options were used in the Wrightington classification, with the basis up to four grades (Table3.2) [13, 15]. Simmen and Huber on the contrary established a classification method purely based on the natural course of the dis- ease, without considering any radiologic inflammatory destruction [12,16]. This classification distinguished the courses into three types. Table3.3 provides information on these three classifications of RA.
There are three main characteristics of the wrist affected by RA: cartilage destruction, synovial proliferation and ligamentous laxity [10, 17]. Cartilage destruction of thinning was occurred due to cytochemical action, which resulting in degradation of existing cartilages and inhibition of new cartilage formation [17].
The synovial proliferation may cause bone erosion with sharp edges which might lead to tendon rupture [10,18]. Ligamentous laxity caused by stretching attributed Table 3.1 Radiographic staging according to Larsen-Daale-Eek [12,14]
Larsen score Radiographic changes
0 Normal joint, no changes
1 Osteoporosis and swelling
2 Joint space narrowing and erosion
3 Significant erosion, moderate destruction
Table 3.2 Wrightington classification [13,15]
Score Radiographic finding Therapy
1 Osteoporosis, cysts, erosion Synovectomy
2 Carpal Instability Soft tissue stabilization/partial arthrodesis 3 Destruction, subluxation Arthroplasty/arthrodesis
4 Severe radial destruction Arthrodesis
Table 3.3 Simmen and Hubber classification [12,16]
Type Natural course of the disease
I Also known as ankylosing type, where spontaneous fusion of the wrist as the indicator II It comes together with arthritic and degenerative changes. This also known as
osteoarthritic type showing both the osteoporosis as well as subchondral sclerosis which affects stabilization
III The wrist with progressive disintegration and instability (luxation, progredient bone loss and mutilation) can be categorized under this disintegrative type. There are two subtypes:
IIIa with more ligamentous instability
IIIb with complete loss of carpal anatomy due to marked destruction of the bone
28 3 The Wrist Joint Affected by Rheumatoid Arthritis
to synovial expansion, results in ulnar translation and carpal supination. The pathological process begins with inflammation of the synovial, affects commonly at the ulnar side of the wrist joint [10,12]. It then spreads to adjacent area of the wrist including the radiocarpal joint. The neighbouring tissues which consist of the cartilages, ligaments and tendons degenerate subsequently. In severe cases, tendon rupture occurs with a consequence of kinematic changes of the joint, resulting in disruption of the periarticular bones and the articular surfaces [9, 19]. On the whole, these three symptoms have critically caused degeneration of both soft tissues and bones, hence eventually mutilated and unstable wrist joint.
Trieb et al. [13] have successfully identified the pathophysiological character- istics of the wrist with RA. Ligamentous laxity for both the intrinsic and extrinsic ligaments has resulted in unphysiological bones movements. This was evident as loss of tension of the radiotriquetral ligament caused dislocation of the carpus in the ulnar direction. Scapholunar dissociation (SLD) due to the increased distance between the scaphoid and lunate is primarily occur because of deteriorated intrinsic ligaments: scapholunar and luno-triquetral which caused by synovial inflammation [20] (Fig.3.3a). Progression of this SLD will also lead to a more severe deformation of the joint, known as scapholunate advanced collapse (SLAC) (Fig.3.3b).
Another pathophysiology characteristic is the dislocation of the proximal carpal row in the ulnar and palmar directions. Ulnar dislocation of the bones was attributed to the weakened radiotriquetral ligament and destructed capitolunate joint, thus resulted in relatively greater load being transferred to the lunate. The reduction of contact between the lunate and the radius was also found in rheumatic wrist due to the dislocation of lunate in the ulnar direction. The scaphoid as the most problematic carpal bone was commonly found to be dislocated palmarly due to deteriorated radioscapholunate ligament. The impaction or loss of carpal height was due to bone erosion and the unphysiological bones dislocations which worsen Fig. 3.3 Radiograph of the wrist with SLD (a) [20] and SLAC (b) [7]
3.2 Rheumatoid Arthritis 29
the functionality and stability of the wrist joint. Hand scoliosis could also be observed in the rheumatic wrist. This was occurred as a result of ruptured tendon, which has led to a changed axis of the wrist to the ulnar, and the rotation of metacarpal in the radial direction.