Hand Therapy Practice Exam Questions 11-15 ANSWERS

11.  Correct Answer:  D.  Both A. and B. 

    This patient is beginning to demonstrate a boutonniere deformity, which may develop after an injury to the central slip of the extensor tendon. 

         Only the central slip can extend the proximal interphalangeal joint (PIP) from a fully flexed position.  The lateral bands may maintain an already extended PIP joint but they cannot initiate PIP extension.  With Elson’s test (Answer A.), the patient keeps the metacarpal phalangeal joint (MCP) in full extension while attempting to extend a fully flexed PIP against light resistance.  An intact central slip will be able to fully extend the PIP joint. 

2        Answer B. describes a  Modified Elson’s test. In the uninjured central slip, this test results in the distal interphalangeal joints (DIP) being positioned in slight flexion.  To the examiner they feel “floppy” due to laxity in the lateral bands.  With an injured central slip the lateral bands shift volarly and transmit forces that extend the DIP joint. It feels stiff instead of lax. 

3       Extending the digit from a fully flexed position and noting any lag in MCP extension (Answer C.) is a test used for sagittal band injury.

Reference:  Rehabilitation of the Hand and Upper Extremity, 6^th edition.  Chapter 38; pg. 502 (location 24255) 

12.  Correct Answer:  C. Neutral wrist-hand-finger orthosis with MCP block

     A pilot study measuring wrist and finger position with various off-the-shelf orthoses in cadavers was done by Apfel, Johnson, and Abrams in 2002 and concluded “a splint that maintains the wrist in neutral position while restraining the digits beyond 75% of a full fist would be most effective in decreasing carpal tunnel pressure.”  With MCP flexion carpal tunnel pressure is increased. This is due to lumbrical incursion into the carpal canal.  The authors cite previous research that showed increased carpal tunnel pressure with lumbrical incursion when fisting is between 75% (finger tips at the level of the thumb web space) and 100% (full fist). Therefore, consideration should be given to both wrist and finger position when choosing or fabricating an orthosis.  While such an orthosis may not be practical for daytime use, it may be appropriate for nocturnal use.   Also, passive and active wrist and finger ROM can be evaluated with an orthosis donned as some orthoses permit more wrist and finger movement while a patient sleeps which will increase carpal tunnel pressure.  The authors mention the Pil-O-Splint as being effective at maintaining both wrist and finger position against active and passive wrist and finger movements.  They state “The Pil-O-Splint was best at restricting “passive composite wrist and finger extension.” This splint limited passive wrist extension to 5° on average and also limited finger extension to 0% of a fist. It was the only splint that restricted any finger PROM and prevented “passive finger flexion” beyond 75% of a full fist. A wide variety of prefabricated splints are currently used in the treatment of CTS. The capability of any prefabricated splint to maintain the desired wrist and finger positions while withstanding passive and active forces occurring during sleep is a very important consideration in splint selection and design.”

Answer A. Resting hand orthosis, may prevent finger flexion but would not position the wrist in neutral.  Answer B. Radial gutter orthosis, would be appropriate in the treatment of a metacarpal fracture but would not be appropriate for treatment of carpal tunnel syndrome.  Answer D. is incorrect for reasons mentioned above.

Reference:

Apfel, A., Johnson, M., & Adams, R. (2002). Comparison of Range-of-Motion Constraints. Journal of Hand Therapy, 15, 226-233. Retrieved July 03, 2018, from https://www.jhandtherapy.org/article/S0894-1130(02)70005-7/pdf.

13.  Correct Answer: A. Pain and hypersensitivity 

Fractures (and crush injuries) of the distal phalanx can cause severe pain and hypersensitivity. This is due to the dense mechanoreceptor innervation found in the finger tips. Hand therapy treatment should include interventions for pain as well as desensitization techniques.  Soft tissue necrosis, infection, or amputation may be complications of an open fracture or crush injury but are less common.

References: Hand Secrets, 3^rd edition, p. 175

Pain and Touch: Handbook of Perception and Cognition, 2^nd edition, pgs. 33-35

14. Correct Answer: A. Lumbricals

The lumbricals originate from the radial side of the tendons of the flexor digitorum profundus in the palm and insert radially into the central slip as well as the lateral band. They are considered the primary flexors of the metacarpal phalangeal (MP) joints the primary extensors of the interphalangeal (IP) joints. They can extend the IP joints regardless of MP position.  The palmar and dorsal interossi (Answers B. and C.) originate from the metacarpals and insert onto the proximal phalanges and act to adduct and abduct the digits, respectively. The ECRB originates from the lateral epicondyle of the humerus and inserts onto the base of the 3^rd metacarpal.  The ECRB (Answer D.) radially deviates and extends the wrist.

Reference: Hand Secrets, 3^rd edition, p. 12

http://www.wheelessonline.com/ortho/lumbricals

15. Correct Answer: C. Both PIP and DIP in 0° extension

Both proximal interphalangeal and distal interphalangeal joints are immobilized in the case of central slip with lateral band repair.  The PIPJ only is immobilized at 0° extension in a zone III repair if the lateral bands have not been surgically repaired as well. This allows distal interphalangeal joint flexion to prevent oblique retinacular ligament stiffness.

Reference: Rehabilitation of the Hand and Upper Extremity, 6^th edition (chap. 39, location 25842)