Lower Limb Prosthetics — MCQs

10 questions

Amputation is often not required in:

Contraindications for skin traction: a) Dermatitis b) Vascularly compromised status of limb c) Abrasions d) Hypopigmentation (vitiligo) e) Bony deformity

The ideal synthetic material used for femoropopliteal bypass when autologous vein is unavailable is:

Following a femoral shaft fracture, your consultant asks you to provide tibia traction. Which of the following will you request from the nurse? 1. Thomas splint 2. K-wire 3. Steinmann pin 4. Denham's pin 5. Bohler's stirrup 6. Bohler Braun splint

Objectives of pre-prosthetic surgical procedures include all, except:

High stepping gait is due to

Maximum shortening of lower limb is seen in:

During reconstruction of an amputated limb which of the following is done first?

Shortest functional level of trans tibial amputation is:

Q10

Which artery is the major supply of the medial surface of the cerebral hemisphere?

Lower Limb Prosthetics Indian Medical PG Practice Questions and MCQs

Question 1: Amputation is often not required in:

A. Buerger's
B. Chronic osteomyelitis (Correct Answer)
C. Diabetic gangrene
D. Gas gangrene

Explanation: ***Chronic osteomyelitis*** - While chronic osteomyelitis can be severe, advancements in **antibiotic therapy**, **surgical debridement**, and **reconstructive procedures** often allow for limb salvage. - The goal of treatment is to eradicate infection and preserve function, making amputation a last resort when other methods fail to control infection or restore viability. *Buerger's* - **Buerger's disease** (thromboangiitis obliterans) is characterized by inflammation and thrombosis of small and medium-sized arteries and veins, primarily in the limbs, leading to severe ischemia and gangrene. - Due to progressive vascular damage and frequent lack of effective medical treatment for advanced stages, **amputation is often required** to remove necrotic tissue and manage intractable pain. *diabetic gangrene* - **Diabetic gangrene** results from a combination of **peripheral neuropathy**, **peripheral arterial disease**, and **infection**, leading to tissue death, particularly in the feet. - The compromised blood supply and impaired wound healing in diabetic patients make these lesions prone to rapid progression and severe infection, with **amputation frequently necessary** to prevent systemic sepsis and death. *Gas gangrene* - **Gas gangrene** is a rapidly progressive and life-threatening infection caused by *Clostridium* species, which produce toxins and gas within tissues. - Due to its aggressive and destructive nature, requiring immediate and extensive surgical debridement often involving **amputation of the affected limb** to remove all infected tissue and prevent widespread systemic toxicity.

Question 2: Contraindications for skin traction: a) Dermatitis b) Vascularly compromised status of limb c) Abrasions d) Hypopigmentation (vitiligo) e) Bony deformity

A. ab
B. abc (Correct Answer)
C. acd
D. bcd

Explanation: ***ab*** - All conditions listed under 'a' and 'b' (Dermatitis, Vascularly compromised status of limb, Abrasions) are **absolute contraindications** for skin traction as they directly compromise skin integrity or circulation. - Applying skin traction in these situations can lead to **skin breakdown**, infection, or further **ischemic damage**, worsening the patient's condition. *ab* - While **dermatitis**, **vascular compromise**, and **abrasions** are indeed contraindications, the option for 'abc' implies there might be other correct choices included, which is not the case for this option. - This option is incomplete as it misses 'c' (Abrasions) which is also a significant contraindication. *acd* - This option incorrectly includes **hypopigmentation (vitiligo)** as a contraindication, which does not inherently prevent skin traction. - It also omits **vascularly compromised status of limb**, a critical contraindication, while including 'a', 'c', and 'd'. *bcd* - This option incorrectly includes **hypopigmentation (vitiligo)** as a contraindication for skin traction. - It also omits **dermatitis**, a key contraindication, while including 'b', 'c', and 'd'.

Question 3: The ideal synthetic material used for femoropopliteal bypass when autologous vein is unavailable is:

A. Dacron
B. Xenograft
C. Saphenous vein
D. PTFE (non-expanded)
E. Cryopreserved vein graft
F. ePTFE (Correct Answer)
. Polyethylene terephthalate (PET)
. Allograft

Explanation: ***ePTFE (Expanded Polytetrafluoroethylene)*** - **ePTFE** is the preferred synthetic graft for femoropopliteal bypass when autologous vein is unavailable - Offers good **biocompatibility** and relative resistance to **thrombosis** - Provides superior patency rates in above-knee femoropopliteal bypasses compared to other synthetic materials (5-year patency ~50-60%) - The expanded structure allows tissue ingrowth and better integration *Dacron (Polyethylene terephthalate)* - Generally used for **larger diameter vessels** (e.g., aortoiliac grafts) - Has **inferior patency rates** in smaller diameter femoropopliteal position compared to ePTFE - More prone to kinking and associated with higher rates of intimal hyperplasia in peripheral circulation *Saphenous vein* - The autologous saphenous vein is the **gold standard** for femoropopliteal bypass with superior long-term patency (5-year patency ~70-80%) - However, this question specifically asks for synthetic material when vein is unavailable or unsuitable - Not always available or of adequate quality in all patients *PTFE (non-expanded)* - **Non-expanded PTFE** lacks the porous structure of ePTFE - Not used for vascular grafts due to absence of tissue ingrowth capability - The **expanded** form is specifically engineered for vascular applications

Question 4: Following a femoral shaft fracture, your consultant asks you to provide tibia traction. Which of the following will you request from the nurse? 1. Thomas splint 2. K-wire 3. Steinmann pin 4. Denham's pin 5. Bohler's stirrup 6. Bohler Braun splint

A. $1,2,3,4,5,6$
B. $3,5,6$ (Correct Answer)
C. $3,4,5$
D. $1,2,4$

Explanation: ***3,5,6*** - For **tibia traction** in a femoral shaft fracture, you would need a **Steinmann pin** for skeletal traction, a **Bohler's stirrup** to apply the traction force, and a **Bohler-Braun splint** to support the limb. - The **Steinmann pin** is inserted into the proximal tibia, the **Bohler's stirrup** attaches to the pin, and the **Bohler-Braun splint** provides a fixed structure for the traction system. *1,2,3,4,5,6* - This option incorrectly includes items not specifically used for applying **tibia traction** (e.g., K-wire is for internal fixation, Thomas splint is for early femur fracture management but not specifically for tibia traction application). - While some components might be used in general fracture management, not all are directly involved in setting up tibia traction as requested. *3,4,5* - This option correctly includes the **Steinmann pin** and **Bohler's stirrup** but incorrectly replaces the **Bohler-Braun splint** with a **Denham's pin**. - A **Denham's pin** is an alternative to a Steinmann pin for skeletal traction, but a **Bohler-Braun splint** is crucial for supporting the limb in this setup, which is missing here. *1,2,4* - This option includes a **Thomas splint** (used for femur fracture support, not tibia traction application), a **K-wire** (used for internal fixation, not traction), and a **Denham's pin** (an alternative to Steinmann pin, but lacks the necessary support and traction application equipment). - These items are not suitable for setting up comprehensive **tibia traction** for a femoral shaft fracture.

Question 5: Objectives of pre-prosthetic surgical procedures include all, except:

A. All of the above (Correct Answer)
B. Removal of epulis fissuratum
C. Correction of unfavorably located frenular attachments
D. Vestibuloplasty

Explanation: ***All of the above*** - The question asks for what is *not* an objective of pre-prosthetic surgical procedures, and since the specific options provided (removal of epulis fissuratum, correction of unfavorably located frenular attachments, and vestibuloplasty) are indeed common objectives, "All of the above" is the correct choice, indicating that none of these procedures are exceptions to the objectives. - The other options represent specific objectives, meaning that they are *included* in the goals of pre-prosthetic surgery. *Removal of epulis fissuratum* - **Epulis fissuratum** is a hyperplastic tissue growth often caused by ill-fitting dentures, and its removal is a common pre-prosthetic surgical procedure. - Its presence can interfere with **denture stability** and cause discomfort, thus its removal is an important objective. *Correction of unfavorably located frenular attachments* - **Frenular attachments** that are too high or thick can dislodge a denture or cause pain, and their surgical correction (frenectomy) is a standard pre-prosthetic procedure. - This procedure aims to improve **denture retention** and comfort by modifying the soft tissue architecture. *Vestibuloplasty* - **Vestibuloplasty** is a surgical procedure designed to increase the depth of the **vestibule**, which is essential for improving denture stability and retention. - This procedure creates a more favorable anatomical foundation for **denture support**, especially in cases of severe alveolar ridge resorption.

Question 6: High stepping gait is due to

A. Gluteus maximum paralysis
B. CDH
C. Quadriceps paralysis
D. Foot drop (Correct Answer)

Explanation: ***Foot drop*** - **Foot drop** causes the patient to lift the leg higher during walking to prevent the toes from dragging on the ground, resulting in a **high stepping gait**. - This condition is often due to weakness or paralysis of the **dorsiflexor muscles** of the foot, typically from **peroneal nerve injury** or **L4/L5 radiculopathy**. *Gluteus maximum paralysis* - **Gluteus maximus paralysis** causes difficulty with hip extension and is often compensated by a **backward lurch** of the trunk during gait. - It results in a **Trendelenburg gait** (if the gluteus medius is also affected) or instability during standing, but not typically a high stepping gait. *CDH* - **Congenital hip dysplasia (CDH)** involves abnormal development of the hip joint. - It usually leads to a **waddling gait** due to instability and pain, or limb length discrepancy, not a high stepping gait. *Quadriceps paralysis* - **Quadriceps paralysis** results in weakness or inability to extend the knee. - Patients typically compensate by hyperextending the knee or leaning forward over the affected leg during gait, which is not a high stepping gait.

Question 7: Maximum shortening of lower limb is seen in:

A. intertrochanteric (Correct Answer)
B. shaft femur
C. Neck femur
D. Transcervical

Explanation: ***intertrochanteric*** - **Intertrochanteric fractures** often lead to significant leg shortening due to the pull of strong hip muscles on the distal fragment, causing displacement and overriding. - The fracture location between the greater and lesser trochanters allows for considerable muscle-driven impaction and proximal migration of the shaft relative to the pelvis. *shaft femur* - **Femoral shaft fractures** can cause shortening, but the degree is often less severe than with intertrochanteric fractures because muscle spasm may be somewhat contained by the surrounding musculature. - While significant displacement can occur, the extensive muscle attachments around the shaft tend to stabilize it more in comparison to the rotational and upward pull seen in intertrochanteric fractures. *Neck femur* - **Femoral neck fractures** primarily cause pain and inability to bear weight, but they typically result in less significant leg shortening compared to intertrochanteric fractures. - Shortening in femoral neck fractures is often due to impaction or slight collapse, not the extensive overriding seen with intertrochanteric breaks. *Transcervical* - **Transcervical fractures** are a type of femoral neck fracture, and thus, they share similar characteristics where shortening is usually less pronounced and primarily due to impaction at the fracture site. - The shortening is often more subtle and related to the degree of collapse at the fracture margin rather than gross displacement of the entire shaft.

Question 8: During reconstruction of an amputated limb which of the following is done first?

A. Arterial repair
B. Venous repair
C. Fixation of the bone (Correct Answer)
D. Nerve anastomoses

Explanation: ***Fixation of the bone*** - **Bone stabilization** is the crucial first step to create a rigid framework, allowing for subsequent precise vascular and nerve repairs. - This prevents movement and tension on delicate repairs, which could lead to failure of the reconnected vessels and nerves. *Arterial repair* - While critical for blood supply, arterial repair is performed *after* bone fixation to ensure the vessels are not disrupted by later bone manipulation. - It's typically done before venous repair to establish arterial flow and identify any potential venous back pressure that needs addressing. *Venous repair* - Venous repair is usually performed after arterial repair, as establishing arterial inflow can help distend the veins, making them easier to identify and repair. - Repairing veins first without establishing arterial flow immediately is less effective and may lead to congestion once arterial flow is restored. *Nerve anastomoses* - Nerve repair is typically the last major step in an amputation reconstruction, following bone stabilization and full vascular repair. - Nerves are fragile and require a stable, well-perfused environment to optimize the chances of successful regeneration.

Question 9: Shortest functional level of trans tibial amputation is:

A. Just proximal to tibial tuberosity
B. 15 cm distal to joint line
C. 10 cm distal to joint line
D. Just distal to tibial tuberosity (Correct Answer)

Explanation: **Just distal to tibial tuberosity** - This level allows for a **short residual limb** but still provides sufficient leverage for effective prosthetic control and weight-bearing. - Amputations at this level generally preserve the **knee joint**, which is crucial for maximizing function and ambulation. *Just proximal to tibial tuberosity* - An amputation **proximal to the tibial tuberosity** would result in a **knee disarticulation** or above-knee amputation, leading to a much greater functional deficit. - This level means losing the **knee joint**, which is not considered a trans-tibial amputation. *15 cm distal to joint line* - This level of amputation would result in a **longer residual limb** than necessary, which can be beneficial, but it's not the *shortest functional* level. - While functional, a longer limb might sometimes present challenges with prosthetic fit or bulk in certain situations. *10 cm distal to joint line* - Similar to 15 cm distal, this length is considered a **standard or optimal length** for trans-tibial amputations, resulting in good function. - However, it is not the **shortest possible functional level** while still retaining an effective limb for prosthetic use.

Question 10: Which artery is the major supply of the medial surface of the cerebral hemisphere?

A. Anterior cerebral artery (Correct Answer)
B. Posterior cerebral artery
C. Middle cerebral artery
D. Posterior inferior cerebellar artery

Explanation: ***Anterior cerebral artery*** - The **anterior cerebral artery (ACA)** is a primary branch of the internal carotid artery and is responsible for supplying blood to the **medial surface** of the frontal and parietal lobes of the cerebral hemispheres [1]. - It also supplies the **corpus callosum**, the superior aspect of the frontal and parietal lobes, and parts of the basal ganglia [1]. *Posterior cerebral artery* - The **posterior cerebral artery (PCA)** primarily supplies the **occipital lobe** and the inferior part of the **temporal lobe** [1]. - It also provides blood to parts of the midbrain and the **thalamus** [1]. *Middle cerebral artery* - The **middle cerebral artery (MCA)** is the largest cerebral artery and supplies most of the **lateral surface** of the cerebral hemispheres [1]. - It is crucial for the blood supply to the **motor and sensory cortices** for the face and upper limb, as well as language areas (Broca's and Wernicke's). *Posterior inferior cerebellar artery* - The **posterior inferior cerebellar artery (PICA)** is a branch of the **vertebral artery** and exclusively supplies the **cerebellum** and the lateral medulla. - It is not involved in the blood supply to the cerebral hemispheres.

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