Total Knee Arthroplasty — MCQs

10 questions

The contraindication to internal fixation -

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

All of the following factors affect osseointegration EXCEPT:

Why is early mobilization important after hip arthroplasty?

Patellar tendon-bearing P.O.P. cast is indicated in the following fracture:

Initial radiological finding seen in knee TB

Mrs. Katson, a 64-year-old obese woman with bilateral knee osteoarthritis, describes pain on most days and limiting pain at least 2 days per week. She has tried activity modification (walking less) without success. All of the following therapies have been shown to be efficacious EXCEPT:

Lachman's test is performed with the knee in what degree of flexion?

A 65-year-old presents with chronic knee pain, varus deformity, and medial joint space narrowing. BMI is 32. Best treatment option?

Q10

Severe disability in primary osteoarthritis of hip is best managed by -

Total Knee Arthroplasty Indian Medical PG Practice Questions and MCQs

Question 1: The contraindication to internal fixation -

A. Fracture dislocation
B. Intraarticular fracture
C. Physeal injury
D. Active infection (Correct Answer)

Explanation: ***Active infection*** - **Active infection** is a strong contraindication to internal fixation because introducing foreign material (implants) into an infected area can spread the infection, make it chronic, and lead to implant failure, osteomyelitis, or sepsis. - The presence of bacteria can colonize the implant surface, forming **biofilms** that are highly resistant to antibiotics and host immune responses, severely complicating treatment. *Fracture dislocation* - **Fracture dislocations** are often a strong *indication* for internal fixation to achieve anatomical reduction and stable fixation, allowing for early mobilization and preventing avascular necrosis or persistent instability. - The goal is to restore joint congruity and maintain reduction, which is difficult to achieve and maintain with non-operative methods. *Intraarticular fracture* - **Intraarticular fractures** are frequently *managed with* internal fixation to restore articular surface congruity, minimize post-traumatic arthritis, and allow for early range of motion. - Precise reduction and stable fixation are crucial to prevent long-term complications such as joint stiffness and osteoarthritis. *Physeal injury* - **Physeal injuries** (growth plate fractures) are often *treated with* surgical fixation, particularly unstable or displaced fractures, to ensure anatomical reduction and prevent growth disturbances. - The fixation technique must be chosen carefully to avoid damaging the physis itself, often using smooth pins or screws that do not cross the growth plate.

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: All of the following factors affect osseointegration EXCEPT:

A. Biocompatibility of implant material.
B. Implant design.
C. Patient's blood type (Correct Answer)
D. Status of the host bed.

Explanation: ***Patient's blood type*** - A patient's **blood type** (e.g., A, B, AB, O) is determined by antigens present on red blood cells and plays no direct role in the biological processes of bone healing or the integration of a dental implant with bone. - While systemic factors can influence osseointegration, blood type itself does not affect the cellular and molecular mechanisms required for direct bone-to-implant contact. *Biocompatibility of implant material* - The **biocompatibility** of the implant material (e.g., **titanium**) is crucial for osseointegration, as it must not elicit adverse reactions and must permit host bone growth on its surface. - Materials that are cytotoxic or inflammatory will prevent bone apposition and lead to fibrous encapsulation rather than direct bone contact. *Implant design* - **Implant design**, including features like **surface roughness**, thread pitch, and macro-geometry, significantly influences the initial stability and long-term success of osseointegration. - A greater surface area and appropriate surface treatments can enhance bone cell attachment and differentiation, promoting faster and stronger bone integration. *Status of the host bed* - The **status of the host bone bed** refers to its quality and quantity (e.g., bone density, vascularity), which are critical for the biological processes of osseointegration. - Adequate bone volume and good bone quality provide a stable foundation and sufficient blood supply for bone regeneration around the implant.

Question 4: Why is early mobilization important after hip arthroplasty?

A. Prevents joint stiffness
B. Prevents DVT
C. Reduces hospital stay
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - Early mobilization is crucial following hip arthroplasty as it offers a multifaceted approach to recovery, addressing **joint stiffness**, the risk of **DVT**, and the duration of **hospital stay**. - This comprehensive benefit highlights the importance of an integrated approach to postoperative care. *Prevents joint stiffness* - While early mobilization helps prevent joint stiffness, it is not the sole benefit, as it also addresses other critical postoperative complications. - Restricted movement in the initial postoperative period can lead to adhesions and **contractures**, limiting the long-term range of motion. *Prevents DVT* - Preventing **deep vein thrombosis (DVT)** is a significant benefit of early mobilization, but it represents only one aspect of its overall importance. - Immobility post-surgery increases the risk of blood clot formation due to venous stasis, making active movement essential. *Reduces hospital stay* - Reducing the length of hospital stay is a key advantage of early mobilization, but it's part of a broader set of benefits that contribute to faster recovery and better outcomes. - Expedited discharge is often a direct result of improved patient mobility, reduced complication rates, and enhanced surgical recovery.

Question 5: Patellar tendon-bearing P.O.P. cast is indicated in the following fracture:

A. Fracture of the tibia (Correct Answer)
B. Fracture of the patella
C. Fracture of the femur
D. Fracture of the medial malleolus

Explanation: ***Fracture of the tibia*** - A **patellar tendon-bearing (PTB) cast** is specifically designed to bypass the knee joint and transfer weight from the patellar tendon to the cast, offloading the tibia. - This design is particularly useful for **stable, distal tibia fractures** where partial weight-bearing is desired to promote healing. *Fracture of the patella* - A PTB cast would place direct pressure on the **patella**, which is contraindicated in a patellar fracture. - Patellar fractures often require a **cylinder cast** or surgical fixation to immobilize the knee. *Fracture of the femur* - Femoral fractures are typically **more proximal** and require **traction**, **internal fixation**, or a **spica cast** for stabilization. - A PTB cast would not provide adequate immobilization or weight-bearing relief for a femoral fracture due to its design. *Fracture of the medial malleolus* - Medial malleolus fractures involve the **ankle joint**, which is distal to the area covered by a PTB cast. - These fractures typically require a **short leg cast** or surgical repair, focusing on ankle stabilization.

Question 6: Initial radiological finding seen in knee TB

A. Reduction of joint space
B. Bone resorption
C. Increase in joint space (Correct Answer)
D. Degeneration of cartilage

Explanation: ***Increase in joint space*** - Early **tuberculous synovitis** leads to synovial hypertrophy and effusion, causing an **increase in joint space** due to fluid accumulation on imaging. - This is the **initial radiological finding** before significant cartilage destruction or bone erosion occurs. - Part of **Phemister's triad** (juxta-articular osteoporosis, peripheral erosions, and gradual joint space reduction in later stages). *Reduction of joint space* - **Joint space narrowing** typically occurs later in the disease as the **cartilage is destroyed**. - This finding is more characteristic of advanced tuberculous arthritis, not the initial stages of knee TB. *Bone resorption* - **Bone resorption (osteolysis)** is a later manifestation of knee TB, often seen with **caseous necrosis** and subchondral bone involvement. - It does not represent the very initial radiological changes, which are primarily synovial-based. *Degeneration of cartilage* - While cartilage is eventually affected by knee TB, **cartilage degeneration** leading to significant changes visualized on imaging is a later event. - The initial presentation is more about synovial inflammation and fluid buildup causing increased joint space.

Question 7: Mrs. Katson, a 64-year-old obese woman with bilateral knee osteoarthritis, describes pain on most days and limiting pain at least 2 days per week. She has tried activity modification (walking less) without success. All of the following therapies have been shown to be efficacious EXCEPT:

A. Glucosamine-chondroitin (Correct Answer)
B. Glucocorticoid steroid intra-articular injections
C. Acetaminophen
D. Total joint arthroplasty

Explanation: ***Glucosamine-chondroitin*** - While widely used and marketed for osteoarthritis, numerous **large, well-designed clinical trials** have consistently shown that **glucosamine-chondroitin supplements** are **not more effective than placebo** in alleviating pain or improving function in osteoarthritis. - The American College of Rheumatology (ACR) and other major medical organizations **do not recommend** its use due to a lack of evidence of efficacy. *Glucocorticoid steroid intra-articular injections* - **Intra-articular corticosteroid injections** provide **short-term pain relief** [1] and reduce inflammation in patients with osteoarthritis, especially during flares. - They are a commonly used and effective treatment for **symptomatic knee osteoarthritis** [1], although repeated injections have potential risks and may not alter long-term disease progression. *Acetaminophen* - **Acetaminophen (paracetamol)** is often recommended as a **first-line oral analgesic** for mild to moderate pain in osteoarthritis due to its relatively favorable side effect profile compared to NSAIDs for long-term use. - It works by **inhibiting prostaglandin synthesis** primarily in the central nervous system, reducing pain perception. *Total joint arthroplasty* - **Total joint arthroplasty (TJA)**, particularly **total knee replacement**, is a highly effective surgical treatment for patients with **severe, end-stage osteoarthritis** [1] who have failed conservative therapies. - It significantly **reduces pain and improves functional outcomes** [1] and quality of life for the vast majority of patients.

Question 8: Lachman's test is performed with the knee in what degree of flexion?

A. 5
B. 20 (Correct Answer)
C. 70
D. 90

Explanation: ***20*** - The **Lachman's test** is most accurately performed with the knee in **20-30 degrees of flexion** to better isolate the **anterior cruciate ligament (ACL)**. - This neutral position allows the posterior capsule and other secondary restraints to be relaxed, making an **ACL tear** more evident during anterior translation of the tibia. *5* - Positioning the knee at only **5 degrees of flexion** is not ideal, as it may keep the **posterior capsule** under too much tension, potentially masking an **ACL injury**. - This position does not adequately relax the secondary stabilizers, which can lead to a false negative result for **ACL laxity**. *70* - At **70 degrees of flexion**, the knee is too bent to effectively assess the **ACL**. - In this position, the **menisci** and other structures can block clear anterior translation, and it is more common for other knee stability tests like the **anterior drawer test** to be performed. *90* - With the knee flexed to **90 degrees**, the **anterior drawer test** is typically performed, not the Lachman's test. - In this position, the **posterior horn of the menisci** can interfere with anterior translation, making the Lachman's test less sensitive for detecting an **ACL tear**.

Question 9: A 65-year-old presents with chronic knee pain, varus deformity, and medial joint space narrowing. BMI is 32. Best treatment option?

A. Arthroscopic Debridement
B. Unicompartmental Knee Replacement
C. High Tibial Osteotomy
D. Total Knee Replacement (Correct Answer)

Explanation: ***Total Knee Replacement*** - This is the most appropriate treatment for a 65-year-old with chronic knee pain, significant **varus deformity**, and **medial joint space narrowing**, indicative of advanced **osteoarthritis**. - A **high BMI (32)** is also a factor that often points towards the need for total joint replacement when conservative measures have failed, as it contributes to increased stress on the knee. *Arthroscopic Debridement* - This procedure is generally reserved for less severe osteoarthritis symptoms or mechanical symptoms like locking, and it is **not effective** for advanced joint degeneration with significant deformity. - It would provide little to no long-term benefit for the presented severe changes and chronic pain. *Unicompartmental Knee Replacement* - While suitable for isolated medial compartment osteoarthritis, a **varus deformity** indicates damage beyond a single compartment or significant malalignment that might not be fully corrected by a unicompartmental approach. - The chronicity, age, and likely degree of degeneration suggest a more comprehensive solution is needed. *High Tibial Osteotomy* - This procedure is typically performed in younger, more active patients with **varus malalignment** and early to moderate osteoarthritis to shift weight to a healthier compartment. - At 65 years old with chronic pain and advanced joint space narrowing, a **corrective osteotomy** is less likely to provide long-term relief and may delay a more definitive solution.

Question 10: Severe disability in primary osteoarthritis of hip is best managed by -

A. Arthroplasty (Correct Answer)
B. Arthrodesis
C. Mc Murray's osteotomy
D. Intra-articular hydrocortisone and physiotherapy

Explanation: ***Arthroplasty*** - **Total hip arthroplasty (THA)** is the most effective treatment for severe osteoarthritis of the hip, providing significant pain relief and functional improvement. - It involves replacing the damaged joint surfaces with **prosthetic components**, addressing advanced cartilage loss and structural damage. *Arthrodesis* - **Arthrodesis (joint fusion)** is an older technique that fixes the joint in a permanent position, eliminating pain but sacrificing all motion in that joint. - While it relieves pain, the severe loss of motion makes it generally less desirable than arthroplasty for the hip, especially in active patients. *Mc Murray's osteotomy* - **McMurray's osteotomy** is a surgical procedure primarily used for some types of **femoral neck fractures** or a specific type of **avascular necrosis** of the femoral head, not for severe osteoarthritis affecting the entire joint. - It involves cutting and realigning the bone, but it does not address advanced, widespread articular cartilage degeneration seen in severe osteoarthritis. *Intra-articular hydrocortisone and physiotherapy* - **Intra-articular hydrocortisone injections** and **physiotherapy** are conservative treatments used for mild to moderate hip osteoarthritis to manage pain and improve function. - These methods do not resolve severe structural damage and are typically insufficient for managing severe disability due to advanced osteoarthritis.

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