Rheumatoid finger deformities: swan-neck, boutonnière and ulnar drift

1. The Nalebuff and Millender classification of rheumatoid swan-neck deformity has four types, based on the degree of proximal interphalangeal flexion assessed in all positions of the metacarpophalangeal joint together with the radiographic state of the proximal interphalangeal joint.

True

Nalebuff and Millender wrote that careful examination to determine the degree of flexion in all positions, together with radiographic examination of the joint, allowed them to group patients into four types, and that surgical procedures are recommended according to this classification. The two axes are proximal interphalangeal mobility (and its dependence on metacarpophalangeal position, the intrinsic-tightness test) and articular preservation: types I and II are mobile, type III is stiff with a preserved joint, and type IV has a destroyed joint. Nalebuff's 1989 review pairs the types with treatment: distal interphalangeal fusion, dermadesis or flexor tenodesis for the mobile finger, lateral band or skin release with restoration of flexor excursion for the stiff finger, and fusion or arthroplasty for the destroyed joint.

• Nalebuff EA, Millender LH. Surgical treatment of the swan-neck deformity in rheumatoid arthritis. Orthop Clin North Am. 1975;6(3):733-52. PMID 1099507
• Nalebuff EA. The rheumatoid swan-neck deformity. Hand Clin. 1989;5(2):203-14. PMID 2661576
• Chung KC, Pushman AG. Current concepts in the management of the rheumatoid hand. J Hand Surg Am. 2011;36(4):736-47; quiz 747. PMID 21463736

2. For a mild, passively correctable rheumatoid boutonnière deformity, Nalebuff and Millender recommended a simple extensor (terminal tendon) tenotomy with dynamic splinting rather than central slip reconstruction.

True

Their 1975 paper states that the rheumatoid boutonnière does not limit hand function significantly until it becomes severe, so procedures should not risk existing function; for the mild cases digital balance can be improved by a simple extensor tenotomy combined with dynamic splinting, in more advanced but passively correctable stages by reconstruction of the extensor mechanism, and for fixed deformities by proximal interphalangeal fusion or arthroplasty. Williams and Terrono restate the same staged approach based on joint deformity, motion, passive correctability and articular surface. Terminal tenotomy corrects the distal interphalangeal hyperextension that is the functional complaint of the mild stage.

• Nalebuff EA, Millender LH. Surgical treatment of the boutonniere deformity in rheumatoid arthritis. Orthop Clin North Am. 1975;6(3):753-63. PMID 1099508
• Williams K, Terrono AL. Treatment of boutonniere finger deformity in rheumatoid arthritis. J Hand Surg Am. 2011;36(8):1388-93. PMID 21741772

3. Rheumatoid swan-neck deformity originates at the proximal interphalangeal joint through laxity of its volar plate, so treatment is directed at that joint.

False

Chung and Pushman explain that swan-neck deformity can arise from the distal interphalangeal joint, the proximal interphalangeal joint or the metacarpophalangeal joint: a mallet posture from distal joint synovitis can cascade proximally into a swan-neck and is treated by distal joint fusion; proximal interphalangeal disease may stretch the volar plate or rupture flexor digitorum superficialis; and at the metacarpophalangeal level subluxation with intrinsic tightness produces the same deformity. Longo adds wrist collapse with relative lengthening of the long tendons as a further mechanism. Treatment is directed at the origin, which is why the deformity is assessed joint by joint; boutonnière, by contrast, is a proximal interphalangeal problem.

• Chung KC, Pushman AG. Current concepts in the management of the rheumatoid hand. J Hand Surg Am. 2011;36(4):736-47; quiz 747. PMID 21463736
• Longo UG, Petrillo S, Denaro V. Current Concepts in the Management of Rheumatoid Hand. Int J Rheumatol. 2015;2015:648073. PMID 26236341
• Nalebuff EA, Millender LH. Surgical treatment of the swan-neck deformity in rheumatoid arthritis. Orthop Clin North Am. 1975;6(3):733-52. PMID 1099507

4. In the multicentre Silicone Arthroplasty in Rheumatoid Arthritis (SARA) cohort, silicone metacarpophalangeal arthroplasty improved patient-reported hand function, aesthetics and satisfaction and corrected ulnar drift and extensor lag, but did not improve grip or pinch strength.

True

In the SARA study (three centres in the United States and England; 70 surgical and 93 non-surgical patients with severe ulnar drift or extensor lag), the surgical group showed significant improvement in the Michigan Hand Questionnaire at one year with correction of ulnar deviation and extensor lag, but no significant improvement in grip and pinch strength; the benefit in function, aesthetics and satisfaction persisted at three years, and at seven years the surgical group had maintained the improvement in ulnar drift and extensor lag with low rates of implant fracture, while grip and pinch strength again did not improve. Non-surgical patients remained stable in hand function over the seven years.

• Chung KC, Kotsis SV, Burns PB, Burke FD, Wilgis EFS, Fox DA, et al.. Seven-Year Outcomes of the Silicone Arthroplasty in Rheumatoid Arthritis Prospective Cohort Study. Arthritis Care Res (Hoboken). 2017;69(7):973-981. PMID 27696739
• Chung KC, Burns PB, Wilgis EF, Burke FD, Regan M, Kim HM, et al.. A multicenter clinical trial in rheumatoid arthritis comparing silicone metacarpophalangeal joint arthroplasty with medical treatment. J Hand Surg Am. 2009;34(5):815-23. PMID 19410984
• Chung KC, Burns PB, Kim HM, Burke FD, Wilgis EF, Fox DA. Long-term followup for rheumatoid arthritis patients in a multicenter outcomes study of silicone metacarpophalangeal joint arthroplasty. Arthritis Care Res (Hoboken). 2012;64(9):1292-300. PMID 22511483

5. Since the introduction of combination DMARD and biologic therapy, rates of hand and foot surgery and of large-joint replacement in rheumatoid arthritis have fallen in parallel.

False

In two UK inception cohorts followed for up to 25 years (2,701 patients; 1,602 procedures in 29%), Nikiphorou found a decline in the 10-year cumulative incidence of intermediate (hand and foot) surgery over time that coincided with the shift from sequential monotherapy to combination DMARDs and biologics, but no decline in major or minor surgery; only the rates of hand and foot surgery showed a consistent fall from 1986 to 2011, whereas large-joint replacement rates remained unchanged. Da Silva's population-based study had already shown that patients diagnosed after 1985 were significantly less likely to undergo joint surgery for rheumatoid disease.

• Nikiphorou E, Carpenter L, Morris S, Macgregor AJ, Dixey J, Kiely P, et al.. Hand and foot surgery rates in rheumatoid arthritis have declined from 1986 to 2011, but large-joint replacement rates remain unchanged: results from two UK inception cohorts. Arthritis Rheumatol. 2014;66(5):1081-9. PMID 24782174
• da Silva E, Doran MF, Crowson CS, O'Fallon WM, Matteson EL. Declining use of orthopedic surgery in patients with rheumatoid arthritis? Results of a long-term, population-based assessment. Arthritis Rheum. 2003;49(2):216-20. PMID 12687513