Proximal Interphalangeal and Metacarpophalangeal Joint Surface Replacement Arthroplasty



Proximal Interphalangeal and Metacarpophalangeal Joint Surface Replacement Arthroplasty


Christopher R. Goll

Peter M. Murray





ANATOMY



  • Anatomy of the extensor tendon mechanism is shown in FIG 1.






FIG 1 • Anatomy of the extensor mechanism of the finger.


PATHOGENESIS



  • Rheumatoid arthritis is a multifactorial entity.



    • The disease is autoimmune mediated and may occur after a bacterial or viral infection.


    • There is a hereditary influence.


    • The B lymphocytes, T lymphocytes, and macrophages lead to proliferation and hypertrophy of synovial cells. The enzymes released by these cells can cause bony erosions, ligamentous laxity, and tendon ruptures.14


  • MCP joint deformities in rheumatoid patients include concentric joint wear as well as ulnar deviation and volar subluxation or dislocation of the proximal phalanx on the metacarpal head (FIG 2).4,15



    • These deformities occur after synovial proliferation in the recesses between the collateral ligaments and the metacarpal head, attenuating the collateral ligaments.


    • Radial inclinations of the metacarpals and wrist joint destruction often leads to an ulnar translation of the entire carpus. This translation can cause ulnar and volar extensor tendon subluxation between the metacarpal heads. Ulnar forces generated by the extensor apparatus and volar forces produced by the flexors lead to ulnar drift of the fingers and fixed MCP flexion deformities or volar dislocations of the MCP joints.


  • Degenerative arthritis affecting the PIP joints of the hand is a process whereby the articular cartilage develops irreversible wear changes, caused by an incompletely understood mechanism. Subchondral bone stiffens and periarticular new bone formation occurs, which leads to restricted joint motion and pain.11


  • Less commonly, degenerative arthritis can affect the MCP joints of the hand. This can occur after trauma, infection, and osteonecrosis or may be idiopathic, having a predilection for the index and long MCP joints.11






FIG 2 • Ulnar drift of the digits.



NATURAL HISTORY



  • Rheumatoid arthritis has a variable prognosis based on the severity of the disease and the structures involved. Mild presentations may go undiagnosed for years, whereas severe presentations may progress to rapid joint destruction in the third or fourth decade of life.


  • Three clinical stages of rheumatoid arthritis exist.



    • First, swelling of the synovial lining, which causes pain, warmth, stiffness, redness, and fullness around the joint


    • Second, synoviocyte hypertrophy and proliferation leading to synovial thickening


    • Third, enzymatic release causing bone and cartilage destruction, ligamentous laxity, and tendon ruptures


  • Medical management as well as surgical management, including synovectomy, can halt or minimize progression of rheumatoid arthritis.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • A thorough patient history and physical examination are important before implant arthroplasty of the fingers.



    • The surgeon should note the patient’s occupation, hobbies, and expectations.


    • The history of the patient’s condition is helpful in gauging the progression of the disease.


    • The primary indication for surface replacement arthroplasty of the MCP or PIP joints is pain relief. Correction of deformity and improvement in function are secondary considerations. It is important to remember that profound deformity may be painless and functional for some.


  • Examination of the entire upper extremity should be performed. Although the order of reconstruction is controversial, deficits of the shoulder, wrist, and elbow should be addressed before addressing hand conditions.


  • Particular attention should be paid to elements of radiocarpal instability, including ulnar translation of the carpus as well as distal radioulnar joint instability. In some situations, a wrist arthrodesis or wrist realignment procedure may be necessary before performing MCP arthroplasties.6



    • Failure to correct carpal collapse and radial deviation of the metacarpals can result in recurrence of ulnar drift deformity after MCP arthroplasty.


  • Careful examination of flexor and extensor tendons of the hand and wrist should be performed. The extensor digiti quinti minimi, extensor pollicis longus, and flexor pollicis longus often rupture in more active forms of rheumatoid arthritis.



    • Extensor tendon or flexor tendon ruptures should be treated before considering implant arthroplasty of the hand.


  • Examination of the PIP joint should include range-of-motion assessment of the joint, assessment of volar plate integrity, central slip integrity, and collateral ligament stability.



    • Normal range of motion of the PIP joint is 0 to 110 degrees.


    • Varus and valgus stability should be compared to the contralateral side.


    • Failure of volar plate integrity in rheumatoid arthritis can lead to swan-neck deformity, which is characterized by PIP joint hyperextension, dorsal subluxation of the lateral bands, and flexion of the distal phalangeal joint. The swan-neck deformity is considered a relative contraindication for surface replacement arthroplasty of the PIP joint (FIG 3A).


    • A boutonnière deformity is caused by failure of the central slip mechanism. This can occur in rheumatoid arthritis or after trauma (FIG 3B). It is characterized by flexion of the PIP joint due to central slip incompetence, volar subluxation of the lateral bands, and hyperextension of the distal interphalangeal (DIP) joint.


  • Normal MCP range of motion is between 0 and 90 degrees.


  • Instability testing: The individual MCP or PIP joints are tested by the examiner grasping the patient’s finger and then applying a valgus and then a varus stress in approximately 30 degrees of flexion. The resultant opening of the joint, or laxity, is compared to the contralateral side. Differences in laxity indicate ligamentous instability. Attempts at hyperextension of the digit at the PIP or the MCP joint can identify volar plate instability and the propensity of the digit to subluxate or dislocate. Surface replacement arthroplasty of either the MCP or the PIP joint is contraindicated in patients with ligamentous instability, as these are semiconstrained devices.



    • Grade 1: no difference in joint line opening compared to the contralateral joint


    • Grade 2: notable opening of the joint line compared to the contralateral joint, but a solid “end point” is reached


    • Grade 3: complete opening of the radial or lateral joint line with valgus or varus stress. This can be demonstrated at either the MCP or the PIP joints. No end point can be discerned.


  • Bunnell test of intrinsic tightness of the PIP joints: The resistance to flexion of the PIP joint encountered with the MCP joint in the extended position is compared with the resistance encountered with the MCP joint in the flexed position. An increase of resistance to flexion of the PIP joint with the
    MCP joint in the extended position indicates intrinsic tightness of that digit.






    FIG 3A. Rheumatoid arthritis of the hand demonstrating swan-neck deformity and volar subluxation of the MCP joints. B. Boutonnière deformity of the digit.



    • It is important to distinguish intrinsic tightness from extrinsic tightness. Extrinsic tightness is encountered when the long extensors of the digits are adherent to either the surrounding soft tissues or the metacarpals. The result is increased resistance to flexion of the PIP joint with the MCP in flexion. In either instance, the limitation of motion is important to clarify, as it can affect the outcome of implant arthroplasty of the MCP or the PIP joint.


IMAGING AND OTHER DIAGNOSTIC STUDIES



  • Posteroanterior, lateral, and oblique views of the hands will adequately image the MCP joints. Brewerton views may add additional information.


  • Posteroanterior and lateral views of the digits are preferred to image the PIP joints.




NONOPERATIVE MANAGEMENT



  • Nonoperative management in rapidly progressing rheumatoid arthritis is largely ineffective.


  • In the quiescent forms of rheumatoid arthritis, nighttime wrist and hand splinting in conjunction with medical management may provide pain relief. Various combinations of prednisone, remitting agents (eg, methotrexate, hydroxychloroquine sulfate, sulfasalazine, adalimumab, etanercept, infliximab, minocycline), and nonsteroidal anti-inflammatory agents may prove effective for extended periods in certain cases.


  • During periods of active rheumatoid arthritis of the MCP joints, corticosteroid injections into the joint may provide acute pain relief and improve function in the short term.


  • The symptoms of MCP and PIP joint degenerative arthritis may come and go, successfully responding to nighttime wrist and hand splinting and nonsteroidal anti-inflammatory agents.


  • Corticosteroid injection into the MCP and PIP joints for advanced degenerative arthritis seldom provides long-term benefits.


SURGICAL MANAGEMENT

Jul 22, 2016 | Posted by in ORTHOPEDIC | Comments Off on Proximal Interphalangeal and Metacarpophalangeal Joint Surface Replacement Arthroplasty
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