THU0431 FREQUENCY OF TENDON INVOLVEMENT AND ITS EFFECT ON HAND FUNCTION IN HAND OSTEOARTHRITIS
Authors: Irina Gessl, Anna Vinatzer, Gabriela Supp, Michael Zauner, Michaela Loiskandl, Martina Durechova, Valentin Ritschl, Josef S. Smolen, Daniel Aletaha, Peter Mandl
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Tenosynovitis and consequent tendon damage are common findings in inflammatory arthritides. In contrast to rheumatoid arthritis (RA) and psoriatic arthritis, little is known about the frequency of tendon involvement in hand osteoarthritis (HOA) and the influence thereof on hand function. Ultrasound has been reported to have a high specificity in diagnosing tenosynovitis and tendon damage. <h3>Objectives</h3> We aimed to appraise the frequency of tendon involvement in HOA and to assess the agreement between ultrasound (US) and clinical diagnosis of tenosynovitis and tendon damage in HOA. In addition, we wanted to assess the influence of tendon involvement on hand function. <h3>Methods</h3> We included 73 patients with HOA in the study. Each patient underwent a clinical as well as a US examination of the 6 extensor tendon compartments and 6 flexor tendons of the hand (fig. 1). They were assessed for US signs of tenosynovitis and tendon damage as well as osteophytes (presence/absence) by a sonographer blinded to clinical information, as well as for clinical tendon involvement (presence/absence) by a biometrician blinded to the US results. Difference in frequency of sonographically detected tendon involvement between flexor and extensor tendons and between right and left hand were calculated by Chi-Square test. Osteophytes were also evaluated on standard radiographs. Agreement between US and clinical examination was calculated by Cohen's kappa. Hand function was quantified using the Score for the Assessment and Quantification of Chronic Rheumatoid Affections of the Hands (SACRAH) questionnaire as well as the Moberg pick-up test (MPUT). Correlation between MSACRAH and tendon involvement was calculated by Spearman's correlation. <h3>Results</h3> In 41 patients (56.2%), at least one tenosynovitis was observed and in 8 (11%) patients, at least one tendon damage was detected by US. Tendon damage was found more often in flexor tendons (0.2% vs. 2.2%, p&lt;0001), while tenosynovitis was found more often in extensor tendons (6.9% vs. 0.7%, p&lt;0001). The right hand was affected more often by tendon damage than the left hand (2.5% vs. 1.1%, p&lt;0.05), but not by tenosynovitis (3.5% vs. 4%, p=0.7). Among all tendons, tenosynovitis affected most often the sixth extensor compartment (in 28.1%), while tendon damage most frequently involved Flexor digitorum II and II (each 4.8%) detected by US (fig. 1). Clinically, any tendon involvement was observed in 57 (78.1%) patients. There was no agreement between the US and the clinical examination on the level of individual tendons (kappa -0.0007) and only slight agreement on the level of individual patients (any affected tendon yes/no) (kappa 0.16). We also found no association between osteophytes (radiographic or US) and tendon involvement regardless of assessment. Neither total MSACRAH nor the MPUT correlated with the number of affected tendons detected by US. However, there was a slightly significant correlation between the number of clinically affected tendons and the MSACRAH subtest for hand function and stiffness. <h3>Conclusion</h3> This study revealed a high frequency of tendon involvement in HOA. The prevalence of tenosynovitis was similar as reported for RA and other inflammatory arthritides. The fact that we could demonstrate marked differences in the distribution of tenosynovitis and tendon damage between and among flexor and extensor tendons as assessed on US, coupled with the overall homogeneous clinical involvement, suggests that clinical examination may be less specific for tendon involvement as compared to US. Tendon involvement on US does not seem to have an impact on hand function in HOA. <h3>Disclosure of Interests</h3> Irina Gessl Grant/research support from: Travel Grant, Anna Vinatzer: None declared, Gabriela Supp: None declared, Michael Zauner: None declared, Michaela Loiskandl: None declared, Martina Durechova: None declared, Valentin Ritschl: None declared, Josef S. Smolen Grant/research support from: AbbVie, Eli Lilly, Janssen, MSD, Pfizer, Roche, Consultant for: AbbVie, Amgen, Astra-Zeneca, Astro, Celgene Corporation, Celtrion, Eli Lilly, Glaxo, ILTOO, Janssen, MedImmune, MSD, Novartis, Pfizer, Roche, Samsun, Sanofi, UDB, Speakers bureau: AbbVie, Amgen, Astra-Zeneca, Astro, Celgene Corporation, Celtrion, Eli Lilly, Glaxo, ILTOO, Janssen, MedImmune, MSD, Novartis, Pfizer, Roche, Samsun, Sanofi, UDB, Daniel Aletaha Grant/research support from: AbbVie, Bristol-Myers Squibb, and MSD, Consultant for: AbbVie, Bristol-Myers Squibb, Eli Lilly, Janssen, Medac, Merck, MSD, Pfizer Inc, Roche, and UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Eli Lilly, Janssen, Medac, Merck, MSD, Pfizer Inc, Roche, and UCB, Peter Mandl: None declared