- Discussion:
-
RA manifests itself in many ways in elbow joint, including
nodules and bursae, synovitis, progressive joint
destruction, antecubital cysts, & ulnar or, rarely
posterior interosseous palsy;
- note that involvement of the RA elbow is infrequently an isolated and therefore it is important to consider
possible involvement in the
wrist and shoulder;
- Synovitis:
- antecubital cysts usually occur during acute episodes of extremely hyperplastic synovitis due to
herniation of synovium thru the relatively weak anterior capsule of the joint;
- nerve palsies also result from synovial herniation;
- ulnar nerve: (see cubital tunnel)
- in case of ulnar nerve, pressure may arise from protrussion of synovium under transverse section
of MCL bridging gap between posterior and anterior bands of that structure;
- synovial cyst confined to cubital tunnel formed by posterior surface of medial epicondyle anteriorly &
arcuate ligament posteriorly can readily give rise to ulnar neuropathy;
- posterior interosseous nerve syndrome:
- any protrussion from synovium is likely to displace PIN against sharp tendinous margins of origin of
ECRB
& superficial humeral lamina of
supinator (ligament of Frohse);
- paralysis of posterior interosseous nerve will result in loss of finger extension
and should be distinguished from
extensor tendon rupture;
- Stages:
1:
soft tissue swelling and osteoporosis
2:
mild narrowing of the joint space and some marginal erosion;
- consider steroids injections, synovectomy, & possibly w/ excision of the head of the radius;
3:
joint space is significantly narrowed;
- main destruction affects humeral-ulnar joint;
- there may occur an anterior subluxation of the radial head;
- here it may act as a mechanical block to flexion & extension, once there is erosive changes in trochlea;
- consider excision of radial head to restore optimal f(x);
- consider total joint replacement for severe intractable pain loss of extension beyond 60 deg, &
instability 2nd to severe bone destruction;
4:
integrity of subchondral plates is breached by deep erosions;
- there is extensive destructive of humeroulnar joint causing trachlear notch of the
olecranon to migrate proximally into deficient trochlea of the humerus;
- w/ humeroulnar destruction, the radial head may be acting as a major stabilising force against the front of the capitellum;
- hence, radial head excision may worsen instability;
- at this stage of the disease consider
joint replacement;
5:
total joint destruction w/ complete loss of normal articular surface
- ironically, as pt passes from stage 4 to stage 5, pt may become pain free, in a way achieveing self arthoplasty;
- Synovectomy:
- pain should be a major indication for this procedure;
- as noted by NST Gendi et al 1997, strongest predictor of good results was limited pronation/supination w/ retained flexion-extension;
- cummlative survival was 81% at one year and decreased 2.6% per year;
- limited flexion-extension was an independent risk factor for a poor result;
- patients may expect better gains in pronation and supination than flexion/extension;
- gains in supination are especially appreciated by patients, because supination cannot be well compensated for by
shoulder motion (unlike pronation which is compensated for by shoulder abduction);
- Total Elbow Replacement:
Synovectomy of the elbow in rheumatoid arthritis.
Elbow synovectomy and excision of the radial head in rheumatoid arthritis: a short term palliative procedure.
Elbow synovectomy in rheumatoid arthritis. Long-term results.
Surgical treatment of the elbow in rheumatoid arthritis.
AD Boyd. Hand Clinics. Vol 5. 1989. p 646-655.
Synovectomy of the elbow and radial head excision in RA. Predictive factors and long term outcome.
NST Gendi et al. JBJS. Vol 79-B. No 6. 1997. p 918.
