eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Swan-Neck Deformity

Author: Roberto Sandoval, MD, Consulting Staff, Department of Emergency Medicine, Anaheim Memorial Medical Center, La Palma Intercommunity Hospital
Coauthor(s): John A Kare, MD, Assistant Professor of Emergency Medicine, Charles R Drew University of Medicine and Science/UCLA, Director of Research, Department of Emergency Medicine, Martin Luther King Jr/Charles R Drew Medical Center; Eleby R Washington III, MD, FACS, Associate Professor, Department of Surgery, Division of Orthopedics, Charles R Drew University of Medicine and Science; Roman V Voytsekhovskiy, MD, Fellow in Hand Surgery, Department of Orthopedic Surgery, Rush University Medical Center; Robert R Schenck, MD, Associate Professor, Departments of Plastic and Orthopedic Surgery, Rush Medical College; Director, Section of Hand Surgery, Department of Plastic and Orthopedic Surgery, Rush University Medical Center
Contributor Information and Disclosures

Updated: Nov 2, 2007

Introduction

Structural deformities of the digits of the hand are common in patients with rheumatoid arthritis (RA). A swan-neck deformity, typically defined as proximal interphalangeal (PIP) joint hyperextension with concurrent distal interphalangeal (DIP) joint flexion, occurs in approximately 50% of patients with RA. However, swan-neck deformity is not unique to RA, because it may also be congenital or traumatic in nature. Multiple surgical procedures are available for the correction of this digital abnormality. The deformity of the finger or fingers must be staged accurately to use the most appropriate surgical technique. The staging of the deformed finger is based on the condition of the articular cartilage — which is determined by radiography — and on the flexibility of the PIP joint.

Problem

Swan-neck deformity is common in persons with RA. It occurs as the end result of rheumatoid synovitis of the metacarpophalangeal (MP), PIP, and/or DIP joints, which disrupts the balance of flexion and extension forces acting across a joint. (See also the eMedicine article Hand, Rheumatoid Hand.) Nalebuff classifies swan-neck deformities into the following 4 types1 :

  • Type I - PIP joints are flexible in all positions.
  • Type II - PIP joint flexion is limited in certain positions.
  • Type III - PIP joint flexion is limited in all positions.
  • Type IV - PIP joints are stiff and have a poor radiographic appearance.

The above classification aids in the choice of surgical treatment for this complex condition.

An alternative classification was proposed by Welsh and Hastings, who classified swan-neck deformity as mobile, snapping, or fixed, on the basis of the condition of the digital intrinsic muscles.2

Welsh and Hastings subdivided swan-neck deformity into 2 types:

  • Type I - Caused primarily by PIP joint disease
  • Type II - Caused primarily by MP joint disease

The Nalebuff classification is the more widely accepted one.

Frequency

Approximately 50% of patients with RA develop a swan-neck deformity.

Etiology

The primary cause of RA is unclear. The inflammation is believed to be a T-cell – mediated immune response against soft tissue and cartilage, leading to synovitis, chondrolysis, and periarticular bone absorption. The disease may be triggered by a combination of factors, including viral infection and a genetic predisposition in patients with the major histocompatibility complex (MHC) class II alleles DR4 and DR1.

The molecular and cellular aspects of RA are better understood. Neutrophils and macrophages accumulate in the synovial fluid because of many chemotactic substances produced by the activation of the inflammatory cascades. Rheumatoid synovium is produced by fibroblastlike stromal cells and angiogenesis. The destruction of cartilage occurs by enzymatic digestion (chondrolysis) and by the inhibition of chondrocyte collagen and proteoglycan synthesis.

Pathophysiology

The pathophysiology of the swan-neck deformity begins with flexor synovitis, which increases the flexor pull on the MP joint. Constant efforts to extend the finger against this pull lead to stretching of the collateral ligaments and the volar plate at the PIP joint.

In a normal finger, intrinsic muscles (interosseous and lumbrical) insert into the lateral bands and serve as flexors of the MP joint and extensors of the PIP and DIP joints by being located volar to the MP joint axis and dorsal to the PIP and DIP joint axes.

In a rheumatoid finger, the lateral bands are constrained in their dorsal position, upsetting the flexor-extensor balance. In this position, the lateral bands increase the pull of the long extensor tendon's central slip, which attaches to the dorsal base of the middle phalanx. The increase of flexor profundus tension resulting from hyperextension of the PIP joint leads to a reciprocal flexion of the DIP joint. Progressive disease causes joint destruction and fixed contracture.

Presentation

Evaluation of the patient with complaints attributable to a joint begins with taking a careful history of the current problem. Although patients occasionally present with point tenderness, individuals with arthrosis often complain of diffuse, dull joint pain.

The proliferation of synovium around a joint can be detected by observing fluctuant swelling beneath the examiner's fingers when the joint is held in 45 º of flexion.

The active and passive ranges of motion of each joint should be measured with a goniometer. Hyperextension is recorded as a negative value.

The lateral stability of each joint should be tested by applying 3-point pressure, with the finger in extension.

The finger in question should also be tested for intrinsic (interosseous and lumbrical) muscle tightness. The examiner should hold the MP joint in full, passive extension and flexion and then gently flex the PIP joint with the other hand. In the normal finger, full PIP joint flexion is possible in extension and flexion of the MP joint. In contrast, in the presence of intrinsic tightness, resistance to PIP joint flexion is encountered when the MP joint is in extension (and the intrinsics are already passively stretched), although when the MP joint is in flexion, passive PIP flexion is possible. The angle of passive PIP flexion is determined with a goniometer and recorded.

Indications

When a patient with RA develops joint deformities that are unresponsive to medical management, surgical intervention is often necessary. These deformities lead to loss of the ability to grip, grasp, and pinch, often leaving the patient unable to perform the activities of daily living. Appropriately timed surgical intervention helps patients return to a greater activity level, which improves the individual's overall medical condition and avoids further deconditioning; independence is greater and self-image is improved.

Patients with RA should be referred to a hand surgery specialist early in the disease's course. Surgical intervention for the swan-neck deformity is advised when active flexion of the PIP joint from its hyperextended position is not possible or occurs with a bothersome snap.

Relevant Anatomy

See Surgical Therapy.

More on Swan-Neck Deformity

Overview: Swan-Neck Deformity
Workup: Swan-Neck Deformity
Treatment: Swan-Neck Deformity
Follow-up: Swan-Neck Deformity
References
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References

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  2. Welsh RP, Hastings DE. Swan neck deformity in rheumatoid arthritis of the hand. Hand. Jun 1977;9(2):109-16. [Medline].

  3. Bickel KD. The dorsal approach to silicone implant arthroplasty of the proximal interphalangeal joint. J Hand Surg [Am]. Jul-Aug 2007;32(6):909-13. [Medline].

  4. Kiefhaber TR, Strickland JW. Soft tissue reconstruction for rheumatoid swan-neck and boutonniere deformities: long-term results. J Hand Surg [Am]. Nov 1993;18(6):984-9. [Medline].

  5. Aronowitz ER, Leddy JP. Closed tendon injuries of the hand and wrist in athletes. Clin Sports Med. Jul 1998;17(3):449-67. [Medline].

  6. Dearborn JT, Jergesen HE. The evaluation and initial management of arthritis. Prim Care. Jun 1996;23(2):215-40. [Medline].

  7. Gainor BJ, Hummel GL. Correction of rheumatoid swan-neck deformity by lateral band mobilization. J Hand Surg [Am]. May 1985;10(3):370-6. [Medline].

  8. Harrison BP, Hilliard MW. Emergency department evaluation and treatment of hand injuries. Emerg Med Clin North Am. Nov 1999;17(4):793-822, v. [Medline].

  9. Lee SJ, Montgomery K. Athletic hand injuries. Orthop Clin North Am. Jul 2002;33(3):547-54. [Medline].

  10. Littler JW. The digital extensor-flexor system. In: Converse JM, ed. Reconstructive Plastic Surgery: Principles and Procedures in Correction, Reconstruction, and Transplantation. 2nd ed. Philadelphia, Pa: WB Saunders; 1977:6.

  11. Nalebuff EA, Millender LH. Surgical treatment of the swan-neck deformity in rheumatoid arthritis. Orthop Clin North Am. Jul 1975;6(3):733-52. [Medline].

  12. Norris ME 3rd, Samra S, DeMercurio J, et al. Free palmaris longus graft tenodesis effectively treats swan neck adduction collapse secondary to thumb basilar joint arthritis. Plast Reconstr Surg. Aug 2007;120(2):475-81. [Medline].

  13. O'Brien ET. Surgical principles and planning for the rheumatoid hand and wrist. Clin Plast Surg. Jul 1996;23(3):407-20. [Medline].

  14. Perron AD, Brady WJ, Keats TE. Orthopedic pitfalls in the emergency department: closed tendon injuries of the hand. Am J Emerg Med. Jan 2001;19(1):76-80. [Medline].

  15. Rosen A, Weiland AJ. Rheumatoid arthritis of the wrist and hand. Rheum Dis Clin North Am. Feb 1998;24(1):101-28. [Medline].

  16. Smrcka V, Dylevsky I. Treatment of congenital swan neck deformity with dynamic tenodesis of proximal interphalangeal joint. J Hand Surg [Br]. Apr 2001;26(2):165-7. [Medline].

  17. Thompson JS, Littler JW, Upton J. The spiral oblique retinacular ligament (SORL). J Hand Surg [Am]. Sep 1978;3(5):482-7. [Medline].

  18. Tuttle HG, Olvey SP, Stern PJ. Tendon avulsion injuries of the distal phalanx. Clin Orthop Relat Res. Apr 2006;445:157-68. [Medline].

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Further Reading

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Keywords

volar plate synovitis, synovitis of capsule, collateral ligament synovitis, finger deformity, arthritis, rheumatoid arthritis, hand deformity, finger deformity, rheumatoid factor, rheumatoid hand, RA, tenosynovitis, swan neck deformity, boutonniere deformity

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Contributor Information and Disclosures

Author

Roberto Sandoval, MD, Consulting Staff, Department of Emergency Medicine, Anaheim Memorial Medical Center, La Palma Intercommunity Hospital
Roberto Sandoval, MD is a member of the following medical societies: American College of Emergency Physicians and American Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

John A Kare, MD, Assistant Professor of Emergency Medicine, Charles R Drew University of Medicine and Science/UCLA, Director of Research, Department of Emergency Medicine, Martin Luther King Jr/Charles R Drew Medical Center
John A Kare, MD is a member of the following medical societies: American Academy of Emergency Medicine, American Medical Student Association/Foundation, and Emergency Medicine Residents Association
Disclosure: Nothing to disclose.

Eleby R Washington III, MD, FACS, Associate Professor, Department of Surgery, Division of Orthopedics, Charles R Drew University of Medicine and Science
Eleby R Washington III, MD, FACS is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American College of Surgeons, American Medical Association, International College of Surgeons, and National Medical Association
Disclosure: Nothing to disclose.

Roman V Voytsekhovskiy, MD, Fellow in Hand Surgery, Department of Orthopedic Surgery, Rush University Medical Center
Disclosure: Nothing to disclose.

Robert R Schenck, MD, Associate Professor, Departments of Plastic and Orthopedic Surgery, Rush Medical College; Director, Section of Hand Surgery, Department of Plastic and Orthopedic Surgery, Rush University Medical Center
Robert R Schenck, MD is a member of the following medical societies: American Association for Hand Surgery, American College of Surgeons, American Medical Association, American Society for Surgery of the Hand, American Society of Plastic Surgeons, American Society of Reconstructive Microsurgery, Chicago Medical Society, and Illinois State Medical Society
Disclosure: Nothing to disclose.

Medical Editor

Joseph E Sheppard, MD, Director of Hand and Upper Extremity, Associate Professor, Department of Orthopedic Surgery, University of Arizona
Joseph E Sheppard, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Medical Association, American Society for Surgery of the Hand, Southern Orthopaedic Association, and Western Orthopaedic Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Robert J Nowinski, DO, Clinical Assistant Professor of Orthopaedic Surgery, Ohio University College of Osteopathic Medicine; Private Practice, Orthopedic Specialists and Sports Medicine, Newark, Ohio
Robert J Nowinski, DO is a member of the following medical societies: American Medical Association and American Osteopathic Association
Disclosure: Nothing to disclose.

CME Editor

Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital
Dinesh Patel, MD, FACS is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Association of Physicians of Indian Origin, American College of International Physicians, and American College of Surgeons
Disclosure: Nothing to disclose.

Chief Editor

Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine
Harris Gellman, MD is a member of the following medical societies: American Academy of Medical Acupuncture, American Academy of Orthopaedic Surgeons, American Orthopaedic Association, American Society for Surgery of the Hand, and Arkansas Medical Society
Disclosure: Nothing to disclose.

 
 
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