O&P Jeopardy

Gait

100

A 34-year-old patient with a traumatic transtibial amputation presents with distal tibial pain that is worse when ambulating. The patient has been dieting and has increased training for an upcoming swim meet. When observing the patient's ambulation, a physician notices excessive up-and-down movement between the limb and socket. Which of the following interventions is an effective initial treatment to decrease distal tibial pain? a. adding additional socks b. providing socket relief at area of pain c. softening the heel of foot or shoe d. strengthening the quadriceps muscles

Answer: A The patient has excessive pistoning during ambulation, which is a frequent cause of distal tibial pain in a transtibial amputee. In this case, it may be due to weight loss related to diet and exercise. The simple solution is adding socks over the liner. Other options to consider if excessive pistoning is noted is to include building up the liner, tightening the socket, and tightening the suspension system. Socket relief is used if socket pressure is elevated. Softening the heel and muscle strengthening can be useful if distal tibial pain is associated with excessive early knee flexion.

200

A patient with a left transfemoral amputation demonstrates a lateral trunk lean towards his prosthetic side. What is the most likely cause? a. Prosthesis too long b. Long residual limb c. Prosthesis aligned in adduction d. Hip abduction contracture

Answer: D Causes of lateral trunk lean towards the prosthetic side include: prosthesis too short, hip abduction contracture, prosthesis aligned in abduction, and short residual limb.

300

A patient has 2/5 strength of his knee extensors. Which of the following compensatory mechanisms will occur during ambulation? a. steppage gait with no heel contact b. thigh external rotation during stance c. knee hyperextension with early foot flat d. increased lumbar lordosis

Answer: C The function of the quadriceps is to support a flexed knee. There is an absence of loading the knee (limited initial contact of the heel) and the knee will be kept in hyperextension during stance to provide stability. The body weight vector will pass anterior to the knee, creating an extension moment and preventing buckling during weight acceptance. Increased lordosis and external rotation of the thigh are compensatory movements for hip flexion weakness. Steppage gait is seen with ankle dorsiflexion weakness

400

In a transfemoral amputee, a circumducted gait pattern, on the prosthetic side, could be caused by which factor? (a) Insufficient prosthetic knee friction (b) Long prosthetic limb (c) Hip flexion contracture (d) Poor balance

Answer (b) When observing gait deviations in an amputee, one should consider both the prosthetic issues and amputee compensatory maneuvers as a potential cause for the deviation. A circumducted gait pattern can have various causes, including a long prosthetic limb, excessive prosthetic knee friction (making it difficult to bend the knee), and hip abduction contracture. Poor balance is usually associated with excessive lateral trunk bending, uneven arm swing, and short stance phase on the prosthetic side.

500

What aspect of gait is improved when a manual locking knee design is chosen for an individual with a unilateral transfemoral dysvascular amputation? (a) Overall gait mechanics with decreased energy consumption (b) Foot clearance in swing phase (c) Stability in stance phase (d) Ability to vary the gait cadence

Answer: (c) The only advantage of a manual locking knee is its inherent stability. It is typically used for patients with significant weakness or instability, such as very low level household ambulators or patients using prosthetic limb for transfers. Since the knee does not bend during swing phase it compromises gait mechanics. Toe clearance is more difficult and the prosthetic limb is typically designed to be shorter than the intact limb.

Pain & Complications

100

Which factor is a known risk for the development of depression following amputation? a. Higher income levels b. Dysvascular etiology c. Phantom limb pain d. Paucity of comorbid conditions

Answer: C Depression is noted in 21% to 35% of persons with limb loss regardless of etiology. Posttraumatic stress disorder (PTSD) is more associated with traumatic etiology. Phantom limb pain and back pain are risk factors for developing clinical depression in persons with limb loss. Other risk factors include low income levels and more comorbid conditions.

200

Which of the following problems is UNLIKELY to lead to tissue breakdown of the distal tibia in a transtibial residual limb? a. The socket is too large. b. The supracondylar wedge is too tight. c. The foot is aligned with excessive dorsiflexion. d. The socket has excessive anterior tilt upon the pylon

Answer: B There are four common socket-related problems that expose the distal tibia to elevated forces that may lead to breakdown: (1) a socket that is too large, (2) a socket that is too broad in the anteroposterior plane ("bell clapper" effect), (3) excessive dorsiflexion of the prosthetic foot, and (4) excessive anterior tilt of the socket on the pylon. A supracondylar wedge would cause proximal breakdown, not distal breakdown.

300

Of the following modalities, which is the most effective in treating phantom limb pain? a. Iontophoresis b. Transcutaneous electrical nerve stimulation c. Short wave diathermy d. Paraffin baths

Answer: B Of the options listed, transcutaneous electrical nerve stimulation (TENS) is the modality that may be useful in treating phantom limb pain. Iontophoresis is generally used for dispersion of medications. Short wave diathermy is a method of deep heat. Paraffin bath is a superficial heat modality.

400

What is the mechanism of action of gabapentin for modulating neuropathic pain? a. GABA (-aminobutyric acid) agonist b. NMDA (N-methyl-D-aspartate) receptor blockade c. Presynaptic calcium channel blockade d. Norepinephrine reuptake inhibitor

Answer: C gabapentin, although structurally related to -aminobutyric acid (GABA), is an alpha2 –delta ligand. The alpha2-delta receptor is a protein associated with neuronal voltage-gated calcium channels. Binding to this channel reduces presynaptic calcium influx into the cell at the dorsal horn, reducing the release of several neurotransmitters (glutamate, substance P, norepinephrine, and calcitonin gene-related peptide [CGRP]).

500

You are evaluating a patient who may require a transtibial amputation. Which factor would be associated with poor postsurgical healing? a. Ankle-brachial index higher than 0.90 b. Monophasic arterial Doppler ultrasound measurement c. Warm limb temperature d. Capillary refill time of 1-2 seconds

Answer: B Blood flow plays a critical role in healing of the residual limb. An ankle-brachial index (ABI) greater than 0.9 is normal and values less than 0.5 are associated with wounds that are unlikely to heal. Normal Doppler ultrasound should reveal triphasic waveforms; monophasic recordings indicate impaired blood flow and would predict poor healing. Cold limb temperature (not arm) would be more associated with poor healing. Capillary refill time of 2 seconds or less is considered normal.

Upper Extremity

100

Which orthosis best corrects a swan neck deformity in rheumatoid arthritis? a. Ring splint b. Spica splint c. Sugar tong splint d. Ulnar deviation splint

Answer: A Ring splints can be used to help correct swan neck deformities in rheumatoid arthritis. They allow flexion but block hyperextension at the proximal interphalangeal (PIP) joint. Thumb spica splints are used for conditions such as DeQuervain tenosynovitis and osteoarthritis. Sugar tong splints are used to immobilize a joint such as the elbow or wrist in patients with fractures. Ulnar deviation splints may be used to correct ulnar deviation in rheumatoid arthritis

200

The main advantage of a long trans-radial amputation compared to a short trans-radial amputation is a. increased room for myoelectric components b. better cosmesis c. increased elbow range of motion d. improved supination/pronation

Answer: D In transradial amputations, the longer residual limb will result in improved supination and pronation which is transferred to the prosthetic device. At a wrist disarticulation level, 120 degrees of supination/pronation is preserved, at the very short level no active functional pronation/supination is available for prosthetic use.

300

In a body-powered upper extremity prosthesis, which feature is an advantage of a voluntary opening device over a voluntary closing device? a. It provides larger prehensile forces. b. Variable prehensile force is transmitted through the control cable. c. There is no need for constant pull on the control cable during grasp. d.It provides indirect sensory feedback.

Answer: C Closing forces in the voluntary opening terminal device rely on springs or rubber bands to provide prehensile force. Typical closing forces range from 5 lbs to 10 lbs. Voluntary closing devices are capable of providing prehensile forces up to 20-25 lbs and provide indirect sensory feedback through the force exerted on the control cable. A disadvantage of the voluntary closing device is the need for a constant pull on the control cable during prolonged grasping.

400

For a person with an upper extremity amputation, what is the advantage of choosing a body powered device over a myoelectric device? (a) Stronger grip force (b) Better cosmesis (c) Lighter weight (d) Less dependence on motor strength

Answer (c) Main advantages of body powered systems are lower initial costs, lighter weight, easier repairs, and better tension feedback to body. dvantages of myoelectric devices are cosmesis, less need for motor strength/coordination to operate limb, and stronger grip force.

500

What prosthesis is most appropriate for a 6-month-old child who has a congenital transhumeral amputation? (a) Curve shaped “banana” arm (b) Myoelectric hand (c) Body powered hook (d) Friction elbow arm

Answer: (a) The banana arm is a passive prosthesis designed to help in reaching and bimanual midline activities in the very young child. A myoelectric hand is most appropriate to initiate about age 1 year; a body-powered hook is appropriate for children age 4-5 years; a friction-elbow arm is appropriate about when a child with a transhumeral amputation starts to walk.

Diabetes

100

A 65-year-old woman with diabetes who will be undergoing an elective transtibial amputation due to a nonhealing wound consults you regarding her upcoming surgery. Which postoperative dressing would you recommend to promote wound healing and prevent postoperative complications? a. Elastic bandages b. Nonadhesive gauze c. Stump shrinker compressive bandage d. Removable or nonremovable postoperative cast

Answer: D The major tenets of postoperative wound management following transtibial amputation are edema control, wound protection and prevention of knee flexion contracture. This is best done with a rigid dressing. Elastic bandages and stump shrinkers can help control edema but may be applied inappropriately. They also do not protect the wound from trauma or prevent knee flexion contracture.

200

A 68-year-old woman with well controlled diabetes is asking your opinion on specialized footwear. She has good pedal pulses, intact sensation and no foot deformity. She has no prior history of ulcers. In addition to frequent foot inspections, you recommend: a. custom molded diabetic shoes. b. well fitting breathable shoes. c. off-the-shelf diabetic shoes with wide toe box. d.custom insert with metatarsal pad.

Answer: B Because she has well controlled diabetes (DM), intact pulses, intact sensation and no obvious foot deformity, this patient is at lower risk. Based on her risk profile, specialized footwear is not recommended. Patients with DM without risk factors for ulcer could be counseled and educated regarding the use of well fitting tennis shoes and sneakers. Other interventions listed could be considered, if ulcer risk factors change.

300

During a routine follow-up of a 75-year-old patient with diabetes and a right transmetatarsal amputation, a physician notices the intact limb has decreased hair growth and is cooler to the touch. A popliteal pulse is easily palpable, but both posterior tibial and dorsalis pedis pulses are not clearly present. The patient does not have claudication. The next most appropriate test in the diagnostic work-up of this patient should be a. venous Doppler. b. arterial angiography. c. transcutaneous partial pressure of oxygen (TcPO2). d. ankle-brachial index (ABI).

Answer: D In this patient, the absent pulses may indicate peripheral arterial disease. Patient is already at high risk for additional limb loss due to diabetes and a previous contralateral amputation. Not all patients with PAD have claudication, so work-up should proceed. The ankle brachial index is a good screening tool and is 95% sensitive is detecting PAD compared to angiography. Angiography is the gold standard for evaluating the arterial system, however, it is invasive and not necessary at this point in the work-up. TcPO2 measures skin perfusion and is most often used to predict wound healing.

400

You see a patient in clinic with what appears to be a non-infected diabetic foot ulcer over the first metatarsal head and order an ankle-brachial index (ABI) study. The patient’s ABI is 1.4. What is your next step in treatment? (a) Proceed with off loading the ulcer, since blood flow is normal. (b) Order additional testing, such as an arterial duplex. (c) Refer for to vascular surgery for urgent revascularization. (d) Refer for consideration of a transmetatarsal amputation.

Answer: (b) Evaluation of vascular status is critical in any patient presenting with diabetic ulcer. The ABI is considered a useful screening tool to look for peripheral arterial disease. Values under 0.91 are considered consistent with peripheral arterial disease. However, calcified vessels can lead to higher values and possibly false negative test results. If ABI is >1.3, this most likely due to calcified, non-compressible vessels; Therefore, other means of testing vascular status should be used.

500

A 65-year-old woman with diabetes mellitus has been sent to your clinic for evaluation of appropriate footwear. She had a diabetic foot ulcer 2 months ago over her first metatarsal head, which is now healed. Examination reveals distal sensory loss and a mild claw foot deformity. Which footwear/orthotic recommendation is the most appropriate? (a) Since the wound is healed, no specialized footwear is needed. (b) Well-fitting regular tennis shoes or sneakers are the best option. (c) Off-the-shelf diabetic shoe with a custom molded orthotic based on severity of claw foot deformity is indicated. (d) Patellar tendon-bearing ankle-foot orthoses to help unload the metatarsal head should be used.

Answer (c) The patient is at high risk for future diabetic foot ulcers based on her history of previous ulcers, claw foot deformity and peripheral neuropathy. Based on this risk profile, specialized footwear is recommended. Patients with diabetes mellitus (DM) without risk factors for ulcer could be counseled and educated regarding the use of well fitting tennis shoes and sneakers. While a custom molded shoe could benefit this patient, they are very expensive and usually needed for patients with severe foot deformity. At this point a prefabricated diabetic shoe and custom orthotic would be clinically appropriate and more cost-effective. A patella tendon bearing ankle-foot-orthosis is not indicated and would not effectively offload the metatarsal heads. A metatarsal bar or pad placed proximal to the metatarsal head is an effective way to offload the metatarsal head.

General O&P

100

Which lower extremity amputee group has the highest probability of successful mobility? a. Dysvascular bilateral transtibial over age 85 b. Dysvascular unilateral transtibial under age 85 c. Traumatic unilateral transtibial under age 85 d.Traumatic unilateral transtibial over age 85

Answer: C The person with a traumatic lower extremity amputation has higher mobility success: 97% of traumatic amputees are ambulating at 3 months. Dysvascular amputees can be successful ambulators but at a lower rate than traumatic amputees. Mobility success in bilateral amputees is less than unilateral amputees. Two studies report that 70% of bilateral transtibial amputees use their prostheses for ambulation. Age greater than 85 years is associated with very low rate of mobility success (2% success in 1 study).

200

What advantage does a suspension system that features a gel liner pin have over a sleeve suspension system in a transtibial amputee? a. Better heat dissipation and reduced sweating b. Improved cushioning and reduction in shear forces c. Ease of donning and doffing d.Ease of liner care and cleaning

Answer: B Because they transmit good control of the prosthesis, offer better cushioning and reduce shear forces on the residual limb, gel liner suspension systems are very popular. They do not provide better heat dissipation, and excessive heat retention and sweating are often major disadvantages. The donning can be difficult, since a gel liner must be positioned correctly on the residual limb to ensure that the pin engages correctly. Lastly, the gel liners require daily cleaning to avoid skin rashes and skin infections.

300

What is the benefit of using ankle-foot orthoses (AFOs) for a patient with Duchenne muscular dystrophy? (a) Improves the patient’s ambulation (b) Assists the patient with rising from the floor (c) Prevents contractures when used at rest (d) Improves wheelchair positioning

Answer: (c) Resting AFOs can help prevent ankle plantar flexion contractures, but are not required for proper wheelchair positioning. Duchenne muscular dystrophy is an x-linked disease with progressive muscle weakness/degeneration that is usually diagnosed in early childhood. Loss of independent ambulation generally occurs in early adolescence, necessitating the transition to a wheelchair. The progressive weakness leads to compensatory strategies for ambulation such that AFOs may further impede ambulation or transferring.

400

What shoe modification can be used to treat medial compartment knee osteoarthritis? (a) Rocker bottom sole (b) Solid ankle cushioned heel (c) Medial wedge (d) Lateral wedge

Answer: (d) Medial compartment osteoarthritis results in genu varum. A lateral wedge can help relieve pain by placing a valgus force at the knee. A medial wedge would exacerbate the problem. Solid ankle cushioned heel is a type of prosthetic foot. A rocker bottom sole is helpful for other conditions such as forefoot fractures, hallux rigidus, foot arthritis, and insensitive feet.

500

Proper positioning for a transtibial amputee should include use of a (a) pillow underneath thigh. (b) pommel between legs. (c) limb board underneath knee. (d) wedge cushion underneath buttocks.

Answer: (c) A limb board placed underneath the knee will help to prevent knee flexion contractures. Placing a pillow underneath the thigh would encourage the development of a hip flexion and possibly a knee flexion contracture. A pommel between the legs may encourage a hip abduction ontracture. A wedge cushion would promote hip flexion contractures.