K Levels and More
You are rounding on an 82 year-old female with a past medical history of uncontrolled diabetes mellitus with severe physical deconditioning secondary to multiple bouts of pneumonia. She is status-post right transtibial amputation due to complications from diabetes. She asks you which type of lower extremity prosthesis you are planning to prescribe for her. You are of the opinion that she will remain nonambulatory for the rest of her life. Which of the following best describes her K-level of ambulation?
K0
In preparation for the residual limb to accept a prosthesis, what is the ideal shape of the residual limb following a transfemoral amputation?
Bonus 100 pts if you can name the ideal shape for transtibial as well.
Conical (transfemoral)
Cylindrical
Which of the following is the most common cause of upper extremity amputation?
A) Hypercoagulable state
B) Trauma
C) Diabetes
D) Cancer
BONUS 100 pts: if you name most common cause for lower limb
B) Trauma
Trauma is the most common cause of upper limb amputation; dysvascular disease due to hypertension, diabetes, factor 5 leiden mutation, etc.) is the most common cause of lower limb amputation
A 17-year-old football player is the local high school’s star running back. In the 2nd game of the season, he attempts to make a cut on a planted right foot. He feels a ”pop” in his right knee and his leg gives out. He has immediate pain and swelling in his right knee and is unable to bear weight on that leg. MRI of the right knee the following day reveals a tear of his ACL (anterior cruciate ligament) and he undergoes surgical reconstruction. Which of the following orthoses is most appropriate post-operatively?
A) Lenox-Hill Derotation Orthosis
B) Unloader Knee Brace
C) Swedish Knee Cage
D) Hinged Knee Brace
A) Lenox-Hill Derotation Orthosis
ollowing ACL reconstruction, a Lenox-Hill derotation orthosis is often used to control axial rotation of the knee as well as medial-lateral and anterior-posterior control. Swedish knee cages are used for knee recurvatum to prevent knee hyperextension. Unloader braces are used most often for knee osteoarthritis; forces are “unloaded” from the more affected/symptomatic compartment, either medial or lateral; these forces are loaded onto the less symptomatic/arthritic side. Hinged knee braces offer increased stability and can be used for a wide array of knee pathologies.
True or False: Children with congenital limb deficiency experience phantom sensation or phantom pain even after conversion to surgical amputation of the limb
False - they do NOT!
Describe a K3 ambulator.
Unlimited community ambulation with a variable cadence.
A patient with a traumatic bilateral transtibial amputation status post bilateral transtibial prostheses would be expected to ambulate with what energy cost of ambulation above normal?
40%
Energy costs of ambulation as a percentage above normal values for various traumatic amputation levels are as follows: Unilateral transtibial amputation: 20%. Bilateral transtibial: 40%. Unilateral transfemoral: 60%. Bilateral transfemoral: 200%. These values are approximations and will vary depending on the patient.
What is the primary advantage of prescribing a prosthetic socket with a total contact fit?
Reduced risk of venous choking
You see a 72 year-old male with CAD, atrial fibrillation, COPD, PAD, HTN, uncontrolled DM2, CKD stage IV, and metastatic lung cancer who presents with bilateral knee pain. His pain is described as aching and worst over the medial aspect of both knees. He denies mechanical symptoms and he does not have any signs of an inflammatory process on exam. He has no signs of ligamentous injury on exam. Gait examination reveals no significant abnormality other than antalgic gait during stance phase bilaterally. Knee radiographs reveal significant subchondral sclerosis, joint space narrowing, and osteophytes primarily located within the medial compartments of bilateral knees. He asks for treatment options, but he states he doesn’t want to try any medications or injections given his complex medical history and he adamantly refuses surgery of any type due to complications from prior surgical interventions. What would be the most reasonable treatment of the options listed?
A) Swedish Knee Cage
B) Rocker Bar
C) Medial Heel Wedge
D) Lateral Heel Wedge
D) Lateral Heel Wedge
A lateral heel wedge would likely provide benefit for his primarily medial knee OA. The lateral heel wedge helps to open the medial compartment and relieve pain. A medial heel wedge would be useful for primarily lateral knee OA. A rocker bar is used to help relieve forces through the metatarsal and can assist with weak plantarflexion. A Swedish knee-cage is indicated to prevent knee recurvatum, but the patient’s gait examination did not reveal knee hyperextension, only antalgic gait.
The most common cause of pediatric acquired amputations
Trauma
Occurring 2x more frequently than disease-related amputation:
- Motor vehicle, motorcycle, train accidents
- Home accidents (ex: burns, fireworks)
How would you assist with dorsiflexion of an AFO?
Spring in the posterior channel
In an AFO, a pin placed in the anterior channel will prevent dorsiflexion. A spring in the anterior channel will assist plantarflexion (will not prevent dorsiflexion, but will assist the opposite movement - plantarflexion). A pin in the posterior channel will prevent plantarflexion. A spring in the posterior channel will assist dorsiflexion.
When prescribing and fabricating a lower extremity prosthesis, it is important to keep in mind pressure-tolerant areas of the lower extremity. Which of the following is NOT a pressure-tolerant area?
A) Medial tibial shaft
B) Patellar tendon
C) Lateral tibial plateau
D) Anterior tibial muscles
C) Lateral tibial plateau
Pressure-tolerant areas of the lower extremity include: Patellar tendon, medial tibial flare, medial tibial shaft, anterior tibial muscles, fibular shaft, popliteal fossa. All other areas are considered pressure-intolerant.
In an amputation surgery, which of the following surgical techniques is most appropriate in patients with severe dysvascular disease?
A) Myodesis
B) Myoplasty
C) Myofasciotomy
D) Myotomy
B) Myoplasty
Myoplasty involves suturing the muscles to each other, and is technically easier. Myodesis involves suturing the muscles into the bone, produces a more stable surgical result, but is contraindicated in patients with severe dysvascular disease, as it will not heal properly due to the poor blood supply.
A frail 80 year-old female with PMH of significant knee osteoarthritis which limits her ambulation presents to your outpatient clinic with mid-low back pain for the past month. She denies known trauma or inciting event. She has no radicular symptoms, denies bowel and bladder dysfunction, and denies saddle anesthesia. She has point tenderness over the thoracolumbar junction in the midline, and her pain is increased with lumbar flexion. X-ray reveals the suspected diagnosis. What brace would be least indicated?
A) Milwaukee brace
B) Taylor brace
C) Jewett brace
D) CASH brace
Milwaukee Brace
From the vignette the most likely diagnosis is vertebral compression fracture. She is an elderly woman who is described as frail, with limited ambulation due to significant knee OA which would make her prone to osteopenic changes. Compression fractures are very common at the thoracolumbar junction, and typically cause anterior wedge deformities which worsen patient’s pain when they assume a lumbar flexion position. Stable compression fractures are often treated without bracing which can cause disuse atrophy of core musculature. However, when bracing is indicated, appropriate choices include Taylor brace, CASH brace, or Jewett brace. A Milwaukee brace is a CTLSO (cervical-thoracic-lumbar-sacral orthosis) most often used for scoliosis.
What is the most common congenital limb deficiency?
Left Terminal Transradial Deficiency
Most common congenital lower limb deficiency: fibular longitudinal deficiency (fibular hemimelia)
You examine a patient’s gait following right transfemoral prosthesis fitting. During ambulation the patient’s left foot plantarflexes excessively during left leg stance phase, vaulting the right lower limb above the ground as it advances through swing phase. Which of the following is a potential cause of this gait abnormality (vaulting on the right side)?
A) Excessive prosthetic foot dorsiflexion
B) Prosthetic foot is set too far laterally
C) Prosthesis is too short
D) Excessive prosthetic knee friction
D) Excessive prosthetic knee friction
Of the answer choices, only excessive knee friction would result in a straight limb which, unable to flex at the knee and clear the foot from the ground, must result in being vaulted up into the air (or perhaps circumducted) in order to clear the ground. A prosthesis being too long, not too short, could also cause vaulting. A prosthetic foot set too far laterally would cause a valgus knee moment. Excessive foot dorsiflexion would cause excessive knee flexion, not extension as observed in this patient.
What is the name for a horizontal amputation through the calcaneus?
Boyd Amputation
You are discussing your patient’s new knee-ankle-foot orthosis (KAFO) with the patient’s orthotist. She mentions that she intentionally offset the KAFO’s hinge joint to sit posterior to the patient’s knee. Which of the following is the most likely purpose of offsetting the hinge posterior to the patient’s knee?
A) To promote knee flexion
B) To cause the line of gravity to fall anterior to the knee
C) To counteract spastic quadriceps
D) To offset the anteriorly placed AFO components
B) To cause the line of gravity to fall anterior to the knee
Offsetting the hinge joint of a KAFO serves the purpose of moving the line of gravity anterior to the patient’s knee, which then tends to lock the knee in extension, producing a stable knee during ambulation that locks appropriately and will not buckle. This is useful in patients with weak quadriceps (not spastic quadriceps) who need extra assistance in extending/locking the knee during ambulation. Promoting knee flexion would occur if the hinge were fixed anteriorly to the patient’s knee.
A 65-year-old previously retired businessman with uncontrolled diabetes (hemoglobin A1C 12%) has developed significant radiating pain down his distal right forearm into his 5th finger. He notices this pain is worse when he flexes his right elbow. The patient is right-handed. EMG/NCS shows severe ulnar neuropathy at the level of the elbow. An orthopedic surgeon recommends against surgery until his diabetes is better controlled and refers the patient to you for further treatment options. What bracing would be most appropriate?
A) Thumb spica splint
B) Long arm splint
C) Ulnar gutter splint
D) Flail arm splint
B) Long arm splint
The most appropriate bracing option for ulnar neuropathy at the elbow is a long arm splint which functions to keep the elbow in 45 degrees flexion. This helps to prevent impingement at the cubital tunnel which would reproduce the patient’s symptoms. A flail arm splint is used after brachial plexus injuries. An ulnar gutter splint immobilizes the 4th and 5th fingers, often to allow for healing after 4th/5th metacarpal or phalange fractures. A thumb spica splint limits thumb ROM, and can be used for DeQuervain tenosynovitis, skier’s thumb, distal 2/3 scaphoid fractures, and 1st CMC arthritis.
What is the most common complication after amputation in the immature child?
Terminal Overgrowth
You are analyzing the gait of a 46 year-old female who is status-post right transfemoral amputation. She has acquired her definitive prosthesis, which involves a locking pin suspension system, polycentric knee unit, and multiaxis foot. As she walks down the hallway, you attempt to detect if any gait abnormalities are present. Which of the following would be expected to cause an excessive prosthetic knee extension moment?
A Socket placed too far anteriorly
B Excessive plantarflexion built into the prosthetic foot
C Foot placed too far posteriorly
D Not enough friction built into the knee unit
B Excessive plantarflexion built into the prosthetic foot
Factors that would be expected to cause excessive prosthetic knee unit extension include: too much friction built into knee unit; too much plantarflexion in the foot, weak quadriceps (causing genu recurvatum), socket placed too far posteriorly; foot placed too far anteriorly. Factors that cause excessive prosthetic knee flexion include: not enough friction built into the knee unit; too much dorsiflexion in the foot; weak quadriceps; socket placed too far anteriorly; foot placed too far posteriorly; knee flexion contracture.
In a Chopart amputation, which of the following bones is spared?
A) Medial cuneiform
B) Cuboid
C) Navicular
D) Talus
D) Talus
A Chopart amputation is an amputation that removes all foot bones except tibia, fibula, and talus. A Lisfranc amputation is a pre-metatarsal foot amputation (sparing all bones proximal to the foot metatarsals). A Boyd amputation is is a horizontal amputation through the calcaneus. A Pirogoff amputation is a vertical amputation through the calcaneus. A Syme amputation spares the tibia, fibula, and calcaneal fat pad (all other bones are removed).
A very active 52 year-old is competing in his first triathlon. The swim portion of the race takes place in the Atlantic Ocean, and he unfortunately is bitten in the right lower extremity by a shark which necessitates a right transfemoral amputation due to significant neurovascular trauma. He successfully undergoes the amputation and is subsequently fitted for an ischial containment socket 4 months later after the incision is healed and edema is controlled. Which of the following is not a typical component of an ischial containment socket?
A) Maintains slight abduction and extended position of the hip
B) Weight borne by ischium
C) Narrow mediolateral diameter
D) Wide AP (anteroposterior) diameter
A) Maintains slight abduction and extended position of the hip
An ischial containment socket is the typical preferred socket following transfemoral amputation. Weight is borne by the ischium. This is a wide A-P and narrow mediolateral diameter socket. The usual positioning is slight hip adduction and flexion; this positioning places the hip abductors and hip extensors in a mild stretch which is mechanically advantageous.
Which of the following motions activates a body-powered upper extremity terminal device?
A) Scapular Retraction with Elbow Extension
B) Humeral Flexion and Scapular Abduction
C) Scapular Retraction
D) Humeral Flexion
Bonus 500 pts: What is the most common activation method for an upper limb body-powered terminal device of a prosthesis?
B) Humeral Flexion and Scapular Abduction
An upper limb body-powered prosthesis is activated with biscapular abduction and humeral flexion, which first flexes the elbow into place, then the elbow position is locked into place with biscapular depression and humeral extension, and then this sequence is repeated to open and close the terminal device.
Bonus: Voluntary Opening
The most common activation method for an upper limb body-powered terminal device is voluntary opening. The terminal device remains closed at rest (safer than open at rest), and only by force from the patient does the terminal device open and allow the patient to grasp something. Voluntary closing is the opposite, and is less common. Proximity opening/closing is not a method.
A 6 year-old boy undergoes a transtibial amputation for a malignant bone tumor in his distal tibia and is fitted with a below-knee prosthesis. At his current age, how often can his prothesis be replaced?
Every 18 months
Until age 5, a prosthetic device should be replaced annually. From age 5-12, a prosthetic device can be replaced every 18 months. A prosthetic device can be replaced every 2 years from age 12-21.