Question 76#

In Dupuytren’s disease:

A. There is an increased ratio of Type I to Type III collagen

There is an increased ratio of Type III to Type I collagen. Studies have shown that Dupuytren’s aponeurosis collagen has an increased proportion of Type III collagen relative to Type I collagen when compared with agematched normal aponeurosis tissues.

References:

1. Bailey AJ, Sims TJ, Gabbiani G, Bazin S. Collagen of Dupuytren’s disease. Clin Sci MolMed 1977; 53 (5): 499-502.
2. Bazin S, Le Lous M, Duance VC, Sims TJ, Bailey AJ, Gabbiani G, D’Andiran G, Pizzolato G, Browski A, Nicoletis C, Delaunay A. Biochemistry and histology of the connective tissue of Dupuytren’s disease lesions. Eur J Clin Invest 1980; 10(1): 9-16.
3. Brickley-Parsons D, Glimcher MJ, Smith RJ, Albin R, Adams JP. Biochemical changes in the collagen of the palmar fascia in patients with Dupuytren’s disease. J Bone Joint Surg [Am] 1981; 63(5): 787-97.

Question 77#

The commonest inheritance pattern for Dupuytren’s disease is:

A. Autosomal recessive

Autosomal dominant. Epidemiological studies on Dupuytren’s disease have suggested an inherited mode of transmission that is more commonly autosomal dominant. However, sporadic cases occur and other modes of inheritance have been implicated.

References:

1. Burge P: Genetics of Dupuytren’s disease [review]. Hand Clin 1999; 15 (1): 63-71.

Question 78#

The following is the commonest cause of distal interphalangeal joint contracture in Dupuytren’s disease:

A. Spiral band

Retrovascular cord of Thomine. The retrovascular cord lies deep (dorsal) to the digital neurovascular bundle. It arises at the proximal phalanx, attaches to the lateral distal phalanx and its development contributes to volar and medial displacement of the neurovascular bundle. It is the usual cause of DIP joint contracture in Dupuytren’s disease.

Question 79#

Absolute indications for surgery in Dupuytren’s disease include:

A. Painless Garrod’s pads

None of the above. It is often stated that any contracture of the PIP joint is an indication for surgery, but McGrouther disagrees based on the results of McFarlane and Botz’s study which showed that when PIP joint contracture was less than 30°, patients were more often made functionally worse, not better, by surgery. This question highlights this point and the surrounding controversy. MPJ contracture can be corrected no matter how long lasting. As stated by McGrouther, it is most important to show loss of function or progression of disease before submitting the patient to time off work, inconvenience, cost and discomfort without a guaranteed long-term outcome.  

References:

1. McGrouther DA. In: Green’s operative hand surgery, 5th ed. Philadelphia, USA: Elsevier-Churchill Livingstone, 2005: 168.

Question 80#

Concerning carpal tunnel syndrome - all are true except:

A. The radial border of the carpal tunnel is the scaphoid and ridge of trapezium

The specificity of nerve conduction studies is less than 70%. This statement is incorrect. The value of nerve conduction studies (NCS) in the diagnosis and evaluation of treatment modalities remains controversial. In 1993, the Quality Assurance Committee of the American Association of Electrodiagnostic Medicine published their critique of the literature available at that time to determine the usefulness of NCS for the evaluation of patients with carpal tunnel syndrome. The specificity of NCS in this circumstance was found to be well in excess of 70% and closer to 95%. The Committee is scheduled to publish a repeat of this study in due course.

References:

1. Jablecki CK, Andary MT, So YT, et al. Literature review of the usefulness of nerve conduction studies and electromyography for the evaluation of patients with carpal tunnel syndrome: AAEM Quality Assurance Committee. Muscle Nerve 1994: 17(12): 1490-1.