Reachout Orthopedics - Issue 2

Radiographic Scoring Methods in Psoriatic Arthritis The measurement of radiographic joint damage in PsA is a core outcome measure in both randomized control trials for novel therapies [60] and longitudinal observational studies [61] and is included in the research agenda as a domain of interest by the Outcome Measures inRheumatology (OMERACT) [62]. The development and validation of scoring methods for PsA have been less well worked out than those for RA. All of the currently used methods have their basis in scoring methods for RA. These instruments include the modified Steinbrocker global scoring method, the modified Sharp score (MSS), and the modified Sharp/van der Heijde score (mSvdHS) for PsA [36, 63]. Until now, the scoring system developed exclusively for PsA is the psoriatic arthritis Ratingen score (PARS) [64]. All these radiographic scores, based on semiquantitative assessment, are summarized in Table 4. As for scoring systems adopted in RA, their lowest common denominator is the large time to perform. Moreover, their scoring requires trained observers. Modified Steinbrocker Global Scoring Method This method was developed at the PsA clinic at theUniversity of Toronto.This classification has been used not only for the mostly affected joint, but also for 40 joints in the hands and feet: all DIP, PIP, and MCP joints of the hands Table 3: Characteristics of the most used scoring methods for rheumatoid arthritis.  van der Heijde modification of the Sharp method (1989) Genant modification of the Sharp method (1998) Modified Larsen method (1995) Type of scoring method  Detailed Detailed Global Description of scoring system  Erosion is assessed in 16 joints for each hand and wrist, and six joints for each foot. One point is scored if erosions are discrete, rising to two, three, four, or five depending on the amount of surface area affected. JSN is scored as follows: 0=normal; 1= focal or doubtful; 2=generalized, less than 50% of the original joint space; 3=generalized, more than 50% of the original joint space or subluxation; 4=bony ankylosis or complete luxation Erosion is scored according to an eight-point scale with 0.5 increments, where 0=normal; 0+=questionable or subtle change; 1=mild; 1+=mild worse; 2=moderate; 2+=moderate worse; 3=severe; and 3+=severe worse. JSN is scored according to a nine- point scale with 0.5 increments, where 0=normal; 0+=questionable or subtle change; 1=mild; 1+=mild worse; 2=moderate; 2+=moderate worse; 3=severe; 3+=severe worse; and 4=ankylosis or dislocation It differentiates six stages from 0 (normal) to 5, reflecting progressive deterioration, and provides an overall measure of joint damage. The grading scale ranges from 0 to 5: 0= intact bony outlines and normal joint space; 1=erosion less than 1 mm in diameter or JSN; 2=one or several small erosions (diameter more than 1 mm); 3=marked erosions; 4=severe erosions (usually no joint space left and the original bony outlines are only partly preserved); and 5=mutilating changes (the original bony outlines have been destroyed) Advantages and disadvantages  Sensitive for detection of radiographic progression but requires training and is time-consuming to apply Sensitive, but presents difficulties in assessing progression of structural damage. Requires training to apply efficiently Semiquantitative global method, easier to learn and use, less sensitive to changes than the modified Sharp method Fig. 3: Genant-modified Sharp scoring method illustrated with figure and grading. a Joints selected in each hand for erosions: 4 PIP, 5 MCP, the IP, the CMC of the thumb, scaphoid, distal ulna, distal radius. The maximum score for both hands is 98. b Joints selected in each foot for erosions: all the MTP joints and the IP joint of the big toe. The maximum score considering both feet is 42. c Joints selected in the hand in the Genant-modified Sharp: the CMC 3, CMC 4, CMC 5 are scored united. The lunate joint is considered for joint space narrowing in the capitate–lunate and radius–lunate joints, whereas the mSvdHS does not include it.The maximum score for both hands is 104. d Joints selected for JSN in each foot: all the MTP joints and the IP joint of the big toe. The maximum score for both feet is 48. CMC carpometacarpal, CSL capitate–scaphoid–lunate, IP interphalangeal joint, Lun lunate, MCP metacarpophalangeal joint, MTP metatarsophalangeal joint, PIP proximal interphalangeal joint, PMC proximal metacarpal, Rad radius, RC radiocarpal, Sc scaphoid ST scaphoid–trapezium, Ul ulna. The “+” sign represents a 0.5 increment found to be 3.9 min for Larsen, 19 min for Sharp, 25 min for the Sharp/van der Heijde method, and 9 min for the Ratingen method [58]. Other studies gave similar results for the Ratingen score method and the Sharp/van der Heijde method [53, 54]. The time needed to score seven radiographs of hands and feet was 7 min for SENS [54], appearing the most feasible in daily clinical practice. The time needed to score 12 radiographs of hands and feet with the Sharp/van der Heijde method for RA ranged from 11.1 to 20.5 min [59]. The time needed is one drawback of both the Sharp method and the Sharp/van der Heijde method; it is related to their higher degree of detail as compared with the Larsen and SENS methods. 6 reachOut Orthopedics