Reachout Orthopedics - Issue 2

of bone on the periosteal and endosteal sur- faces accompanied by thickening of the tra- beculae can cause radiodensity of an entire phalanx (“ivory phalanx”), another manifes- tation of bone proliferation. Intraarticular osseous fusion of joints predominantly affects DIP and PIP joints. Table 1 summarizes the main radiological differences between RA and PsA. Radiographic Scoring Methods in Rheumatoid Arthritis As discussed above, in RA all the synovial joints can be affected but only some joints in a scoring method can be included. Small joints are the most frequently affected, and Scott et al . [34] showed that they could give a good representation of the global progression of damage. Another advantage that is given from the use of hand and wrist X-rays is that erosions are easier detectable in small joints than in the large ones. X-rays of hands and wrists have been used for the creation of the previous scoring systems for RA. Several authors showed in inception cohort studies of patients with early RA that MTP are eroded earlier and show more damage [35, 36]. These studies indicate the importance to include feet in a scoring method assessing RA radiographic damage. The scoring systems that have been de- signed to evaluate radiographic changes in RA can be divided into two main groups: global and detailed. Global scoring systems assign one score to the entire joint, taking into account all the abnormalities seen, whereas detailed systems assign scores on at least two separate variables for each joint evaluated [37, 38]. Radiographic scores, such as the Larsen and Sharp scores [39] and their modifications [40, 41], are the standard methods for deter- mining joint damage and its progression [42, 43]. Table 2 summarizes the main RA features included in the different radiographic scoring methods described below. Sharp Scoring Method (1971) In 1971, Sharp and colleagues proposed a detailed scoring method for the hands and wrists that is divided into two scores, one for erosions and the other for JSN [44]. The number and selection of joints in the Sharp score evolved in the years, and a modification proposed in 1985 of the Sharp method [45] is now considered the standard for the method. Larsen Scoring Method (1977) The Larsen method was developed by Larsen et al . [39]. It has been modified several times by the authors [46]. It is a 6-point global scoring of joints, based primarily on erosive damage. However, grade 1 can be based on soft tissue joint swelling only, which is not a real sign of structural damage and is also difficult to assess reliably. The method can be applied to many joints but is primarily used for the hands and wrists and also for the feet. Larsen produced a set of standard reference films to compare the grading of the joints. Modified Sharp Method (1985) Sharp et al . [45] further defined which joints to score based on the frequency of RA involvement. They decreased the number of joints of each hand/wrist to 17 for erosions and 18 for JSN. Therefore, the final Sharp method includes two scores, one for erosions and the other for JSN. Erosions are counted when discrete, and surface erosions are scored according to the surface area involved [45]. Kaye Scoring Method (1987) Kaye et al . [47] combined and modified the methods described by Genant [48] and Sharp et al . [45]. In this method, malalignment is scored in addition to erosions and JSN. Some of the joints that were evaluated in the Genant and Sharp methods were excluded and/or combined. Sites were considered inevaluable if they were missing from the radiograph or if they had flexion deformity. Inevaluable joints were not scored and were therefore excluded from analysis. van der Heijde-Modified Sharp Scoring Method (1989) The most noticeable difference in the van der Heijde modification is the addition of the joints of the forefoot. Another change was the decreased number of joints in each hand/ wrist scored [49]. Some sites (triquetrum for erosions and lunate triquetrum, first IP joint and radioulnar joint for JSN) were difficult to assess in a reliable fashion, mainly due to superimposition, and often were difficult to score leading to interobserver disagreement. The Sharp/van der Heijde scoring system is currently the most widely used radiographic scoring system in clinical trials in RA including biological agents [16–20, 22, 23, 50, 51] (Fig. 1). Modified Larsen Method (1995) A modification of the original method [39] to evaluate radiographs in long-term studies was proposed later by Larsen et al . [46]. It incorporates several changes in the original method: scores for the thumbs and first MTP were deleted; the wrist was divided into four quadrants, and a distinction was made between erosions of different sizes (Fig. 2). Genant-Modified Sharp Scoring Method (1998) Similar to Sharp’s method, Genant [48] scored erosions and JSN separately. The Genant modification of the Sharp method focuses on 14 sites for erosions and 13 sites for JSN. In Table 3 are shown the joints con- sidered for erosions and JSN and the grading. Comparison of Genant–Sharp and van der Table 2: Features of rheumatoid arthritis included in the Sharp and in the Larsen scoring systems and further modifications. Scoring method Erosion JSN Osteoporosis Soft tissue swelling Alignment/ (sub)luxation Ankylosis Cyst Sharp (1971) + + – – – + + Larsen (1977) + + + + – – – Modified Sharp (1985) + + – – – + – Kaye (1987) + + – – + + + Van der Heijde/Sharp (1989) + + – – + + – Modified Larsen (1995) + + – – – – – Genant (1998) + + – – + + – Ratingen score (1998) + + – – – – – SENS (1999) + + – – + + – JSN joint space narrowing, SENS simplified erosion narrowing score += included in the scoring system; –=not included in the scoring system 4 reachOut Orthopedics