Arthroplasty — MCQs
On this page
Which of the following is considered a fenestrated hip prosthesis?
A patient with an orthopaedic hip implant is to undergo dental extraction. What antibiotic prophylaxis is recommended?
Who is considered the father of joint replacement surgery?
During hip replacement surgery, loss of joint and ligament receptors leads to which of the following outcomes regarding sensation and proprioception?
Which of the following are major indications for arthroplasty?
Patellar clunk is a known complication of which surgery?
A Baker's cyst is a type of:
What is the best treatment for a fracture neck of femur in a 65-year-old lady?
Aseptic loosening in cemented total hip replacement occurs as a result of a hypersensitivity response to which of the following?
The Watson-Jones approach is indicated for which of the following conditions?
Arthroplasty Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is considered a fenestrated hip prosthesis?
- A. Bipolar prosthesis
- B. Austin Moore prosthesis (Correct Answer)
- C. Thompson prosthesis
- D. All of the above
Explanation: **Explanation:** The correct answer is **Austin Moore prosthesis**. In orthopaedic surgery, a **fenestrated prosthesis** refers to an implant with "windows" or openings in its stem. These holes allow for bone to grow through the prosthesis (biological fixation), providing long-term stability. **1. Why Austin Moore is correct:** The Austin Moore prosthesis is a unipolar hemiarthroplasty implant used for femoral neck fractures. Its defining feature is a **fenestrated stem**. During surgery, bone chips are often packed into these fenestrations; over time, bone grows through these holes (osseointegration), anchoring the prosthesis to the femoral shaft without the need for bone cement. **2. Why the other options are incorrect:** * **Thompson prosthesis:** This is also a unipolar prosthesis, but it has a **solid (non-fenestrated) stem**. It is designed to be used with bone cement (Polymethylmethacrylate - PMMA) for fixation. * **Bipolar prosthesis:** This refers to an implant with two points of articulation (one at the acetabulum and one within the prosthetic head). While the stem design can vary, the term "bipolar" describes the head mechanism, not the presence of fenestrations. **High-Yield Clinical Pearls for NEET-PG:** * **Fixation:** Austin Moore = **Uncemented** (Press-fit/Biological); Thompson = **Cemented**. * **Indications:** Austin Moore is preferred in patients with good bone quality; Thompson is preferred in osteoporotic patients where cement provides immediate stability. * **Calcar:** The Austin Moore prosthesis has a collar that rests on the calcar femorale to prevent subsidence. * **Complication:** A common complication of unipolar prostheses (Moore/Thompson) is **acetabular erosion** (protrusio acetabuli) because the metal head rubs directly against the native cartilage.
Question 2: A patient with an orthopaedic hip implant is to undergo dental extraction. What antibiotic prophylaxis is recommended?
- A. Amoxicillin 3 times a day for 3 days before the procedure
- B. Amoxicillin 3 times a day for 1 day before the procedure
- C. Amoxicillin intravenously 1 hour before the procedure
- D. Antibiotic prophylaxis is not required (Correct Answer)
Explanation: **Explanation:** The correct answer is **D. Antibiotic prophylaxis is not required.** **1. Underlying Medical Concept:** Historically, it was believed that dental procedures could cause transient bacteremia leading to Late Prosthetic Joint Infection (PJI). However, current evidence-based guidelines from the **American Academy of Orthopaedic Surgeons (AAOS)** and the **American Dental Association (ADA)** state that there is no direct link between dental procedures and PJI. Routine antibiotic prophylaxis is **not recommended** for patients with prosthetic joint replacements undergoing dental procedures. The risks of antibiotic use (allergic reactions, *C. difficile* infection, and antimicrobial resistance) outweigh the unproven benefits of preventing joint infection. **2. Why Incorrect Options are Wrong:** * **Options A and B:** Prophylaxis is never administered for multiple days or a full day before a procedure. If prophylaxis were indicated (e.g., for infective endocarditis), it would be a single pre-operative dose. * **Option C:** While IV antibiotics are used for surgical prophylaxis (like during the arthroplasty itself), they are not indicated for dental work in patients with joint implants. **3. Clinical Pearls for NEET-PG:** * **Exception:** Prophylaxis may be considered only in **severely immunocompromised** patients (e.g., stage 3 AIDS, chemotherapy, or recent organ transplant) with poorly controlled oral infections, and even then, only after consultation between the dentist and the orthopedic surgeon. * **Timing:** If prophylaxis is deemed necessary for other reasons (like high-risk cardiac conditions), the standard dose is **2g Amoxicillin orally 30-60 minutes before** the procedure. * **High-Yield Fact:** The most common cause of Late PJI is hematogenous spread, but the source is usually skin or urinary tract infections, not dental flora.
Question 3: Who is considered the father of joint replacement surgery?
- A. Manning
- B. Gridlestone
- C. Charnley (Correct Answer)
- D. Ponseti
Explanation: **Explanation:** **Sir John Charnley** is universally recognized as the **"Father of Modern Joint Replacement"** for his pioneering work in Total Hip Arthroplasty (THA). In the early 1960s, he revolutionized the field by introducing the **Low Friction Arthroplasty (LFA)**. His three landmark contributions include: 1. The use of **Ultra-High-Molecular-Weight Polyethylene (UHMWPE)** for the socket. 2. The use of **Polymethylmethacrylate (PMMA)** bone cement for stable fixation. 3. The concept of a **small diameter femoral head (22.25 mm)** to reduce torque and wear. **Analysis of Incorrect Options:** * **Manning:** Not associated with the development of joint replacement; likely a distractor in the context of orthopedic history. * **Girdlestone:** Known for the **Girdlestone excision arthroplasty**, which involves removing the femoral head and neck without replacement. It is now primarily used as a salvage procedure for infected hip replacements. * **Ponseti:** Famous for the **Ponseti technique**, the gold standard non-operative treatment for Congenital Talipes Equinovarus (CTEV/Clubfoot) using serial casting. **High-Yield Clinical Pearls for NEET-PG:** * **Charnley’s Triad:** Low friction principle, Bone cement (PMMA), and UHMWPE. * **PMMA:** Acts as a grout (filler), not a glue. A common complication during its insertion is **Bone Cement Implantation Syndrome (BCIS)**, characterized by hypoxia and hypotension. * **Clean Air Rooms:** Charnley also pioneered the use of laminar airflow in operating theaters to reduce surgical site infections.
Question 4: During hip replacement surgery, loss of joint and ligament receptors leads to which of the following outcomes regarding sensation and proprioception?
- A. No significant loss of joint sensation or proprioception. (Correct Answer)
- B. Complete loss of all joint sensations and proprioception.
- C. Joint sensation is lost only in unstable positions.
- D. A decrease in proprioception and a decrease in motor control.
Explanation: ### Explanation **1. Why Option A is Correct:** Total Hip Arthroplasty (THA) involves the removal of the femoral head and acetabular cartilage, which contain mechanoreceptors (Ruffini endings, Pacinian corpuscles, and Golgi-like organs). While these intra-articular receptors are lost, **proprioception and joint sensation are largely preserved** because the majority of proprioceptive feedback for the hip joint is derived from the **surrounding musculature (muscle spindles), tendons (Golgi tendon organs), and the remaining joint capsule.** Studies have shown that after the initial postoperative recovery, patients often demonstrate proprioceptive accuracy similar to or even better than their pre-operative state, likely due to the relief of pain and restoration of mechanical stability. **2. Why the Other Options are Incorrect:** * **Option B:** This is a common misconception. Proprioception is a multi-modal system; losing one component (intra-articular receptors) does not lead to a "complete loss" because extra-articular structures remain intact. * **Option C:** Joint sensation is not position-dependent in this manner. While mechanoreceptors fire more at terminal ranges of motion, the overall sensation remains functional throughout the arc of movement due to muscular feedback. * **Option D:** In the long term, THA generally **improves** motor control by restoring the center of rotation and improving the lever arm of the abductor muscles (Gluteus Medius), rather than decreasing it. **3. Clinical Pearls for NEET-PG:** * **Mechanoreceptors:** The hip capsule contains four types of receptors. Type I (Ruffini) and Type II (Pacinian) are the most critical for signaling joint position. * **Pain vs. Proprioception:** Chronic osteoarthritis actually impairs proprioception due to pain-induced inhibition. Therefore, replacing the joint often results in a net **gain** in functional proprioception. * **High-Yield Fact:** The **Gluteus Medius** is the most important muscle for post-operative hip stability and gait (Trendelenburg sign); its nerve supply (Superior Gluteal Nerve) must be protected during the lateral approach.
Question 5: Which of the following are major indications for arthroplasty?
- A. Osteoarthritis of the hip (Correct Answer)
- B. Ankylosis of the elbow
- C. Ununited tibial fracture
- D. Ununited femoral neck fracture
Explanation: **Explanation:** Arthroplasty is a reconstructive surgical procedure aimed at restoring the function of a joint by resurfacing or replacing it. The primary goals are pain relief and restoration of mobility. **1. Why Option A is Correct:** **Osteoarthritis (OA) of the hip** is the most common major indication for total hip arthroplasty (THA). In advanced OA, the articular cartilage is destroyed, leading to "bone-on-bone" contact, debilitating pain, and loss of range of motion. Arthroplasty provides a definitive solution by replacing the damaged joint surfaces with prosthetic components, significantly improving the patient's quality of life. **2. Why the Other Options are Incorrect:** * **Ankylosis of the elbow (B):** While arthroplasty can be done for ankylosis, it is technically challenging and often considered a relative indication. In many cases of elbow ankylosis (especially post-traumatic), excision arthroplasty or functional bracing is preferred over prosthetic replacement due to high complication rates. * **Ununited tibial fracture (C):** Non-union of long bone diaphyses (like the tibia) is managed with stable internal fixation (e.g., intramedullary nailing or plating) and bone grafting, not joint replacement. * **Ununited femoral neck fracture (D):** While hemiarthroplasty or THA is a treatment for femoral neck fractures in the elderly, the *primary* indication for arthroplasty in trauma is the fracture itself (to avoid avascular necrosis), not necessarily the "un-union" stage, which might sometimes be managed with valgus osteotomy in younger patients. **High-Yield Clinical Pearls for NEET-PG:** * **Most common indication for THA:** Osteoarthritis. * **Most common indication for TKA (Knee):** Osteoarthritis. * **Absolute Contraindication:** Active systemic or local infection (sepsis/septic arthritis). * **Charnley’s Low Friction Arthroplasty:** The "Gold Standard" design for THA using a metal head and a polyethylene socket.
Question 6: Patellar clunk is a known complication of which surgery?
- A. Corrective osteotomy for genu valgum
- B. Total knee replacement (Correct Answer)
- C. Medial patellofemoral ligament reconstruction
- D. Bicondylar plating of proximal tibia fracture
Explanation: **Explanation:** **Patellar Clunk Syndrome** is a specific complication associated with **Total Knee Replacement (TKR)**, particularly in Posterior-Stabilized (PS) designs. It occurs due to the formation of a painful fibrous nodule at the superior pole of the patella (at the junction of the quadriceps tendon and the proximal patellar button). When the knee moves from flexion to extension (typically between 30° and 45°), this nodule gets caught in the intercondylar notch of the femoral component and then "pops" or "clunks" out as the knee straightens. **Analysis of Options:** * **Option A & D:** Corrective osteotomies and proximal tibia plating involve extra-articular or intra-articular bone realignment/fixation. While they may cause stiffness or patellofemoral pain, they do not involve the prosthetic intercondylar notch necessary to produce a "clunk." * **Option C:** MPFL reconstruction addresses patellar instability. While it can lead to over-tightening or restricted motion, it does not involve the specific fibrous-prosthetic impingement seen in TKR. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factor:** More common in **Posterior-Stabilized (PS)** knee designs because the "box" (intercondylar notch) provides a space for the nodule to entrap. * **Clinical Presentation:** A painful "catch" or audible "thud" during active knee extension. * **Management:** Initial treatment is conservative, but definitive treatment is **arthroscopic debridement** (resection of the fibrous nodule). * **Prevention:** Modern TKR designs have a more "anatomical" femoral trochlea and a superiorly placed box to reduce this impingement.
Question 7: A Baker's cyst is a type of:
- A. Pulsion diverticulum of the knee joint (Correct Answer)
- B. Retention cyst
- C. Bursitis
- D. Benign tumor
Explanation: **Explanation:** A **Baker’s cyst** (also known as a popliteal cyst) is not a true cyst but rather a **pulsion diverticulum** of the synovial membrane of the knee joint. 1. **Why Option A is Correct:** The cyst is formed by the herniation of the synovial membrane through the posterior capsule of the knee, typically between the medial head of the gastrocnemius and the semimembranosus tendons. It occurs due to increased intra-articular pressure (pulsion) caused by underlying joint pathology (e.g., osteoarthritis or meniscal tears). A one-way valve mechanism allows synovial fluid to enter the cyst but prevents it from returning to the joint. 2. **Why other options are incorrect:** * **Retention Cyst:** These occur due to the obstruction of a gland's duct (e.g., sebaceous cyst). Baker’s cysts are formed by pressure-driven herniation, not ductal blockage. * **Bursitis:** While a Baker’s cyst often involves the gastrocnemio-semimembranosus bursa, it is specifically a communication/herniation of the joint space rather than simple primary inflammation of a bursa. * **Benign Tumor:** It is a fluid-filled reactive sac, not a neoplastic growth of cells. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most commonly found in the **posteromedial** aspect of the popliteal fossa. * **Associated Conditions:** In adults, it is usually secondary to **Osteoarthritis** (most common) or Rheumatoid Arthritis. In children, it is often primary and idiopathic. * **Foucher’s Sign:** The cyst becomes firm on knee extension and soft on flexion (helps differentiate it from a popliteal artery aneurysm). * **Complication:** Rupture of the cyst can mimic **Deep Vein Thrombosis (DVT)**, presenting with sudden calf pain and swelling (Pseudothrombophlebitis).
Question 8: What is the best treatment for a fracture neck of femur in a 65-year-old lady?
- A. Pop cast
- B. Gleohy - I suspect this is a typo and should be 'Galeal tendon' which doesn't fit here, or potentially a less common fracture treatment term. I will assume it's a typo and leave it as is for now, but it is highly suspect.
- C. Bone grafting and compression
- D. Hemireplacement arthroplasty (Correct Answer)
Explanation: **Explanation:** The management of a fracture of the neck of the femur is primarily determined by the **age of the patient** and the **displacement of the fracture**. In an elderly patient (typically >60–65 years), the blood supply to the femoral head (via the retinacular vessels) is highly precarious. Displaced fractures carry a high risk of **Avascular Necrosis (AVN)** and non-union. **Why Hemireplacement Arthroplasty is correct:** For a 65-year-old patient, the goal is early mobilization to prevent complications of prolonged bed rest (like DVT or pneumonia). Hemireplacement arthroplasty (e.g., Austin Moore or Bipolar prosthesis) allows for immediate weight-bearing and avoids the high failure rate associated with internal fixation in osteoporotic elderly bone. **Analysis of Incorrect Options:** * **A. Pop cast:** Hip fractures are "unstable" and cannot be managed by immobilization in a cast. This leads to malunion and fatal complications of recumbency. * **B. Gleohy:** This appears to be a typographical error (likely intended to be Girdlestone excision arthroplasty or a similar term). Regardless, excision arthroplasty is a salvage procedure, not a primary treatment. * **C. Bone grafting and compression:** This is generally reserved for younger patients (<55 years) where "head-salvage" is the priority. In a 65-year-old, the risk of AVN outweighs the benefits of attempting to save the natural femoral head. **NEET-PG High-Yield Pearls:** * **Young patients (<55 yrs):** Emergency ORIF (Internal fixation) with Cannulated Cancellous Screws. * **Elderly (>65 yrs) & Sedentary:** Hemireplacement Arthroplasty. * **Elderly (>65 yrs) & Active:** Total Hip Arthroplasty (THA) is preferred over Hemireplacement to provide better long-term functional outcomes. * **Garden Classification:** Used to grade displacement; Stages III and IV have the highest risk of AVN.
Question 9: Aseptic loosening in cemented total hip replacement occurs as a result of a hypersensitivity response to which of the following?
- A. Titanium debris
- B. High-density polyethylene debris (Correct Answer)
- C. N,N-Dimethyltryptamine (DMT)
- D. Free radicals
Explanation: **Explanation:** **Aseptic loosening** is the most common cause of long-term failure in total hip replacement (THR). The primary pathophysiology involves a biological response to wear debris, known as **"Particle Disease."** 1. **Why High-density polyethylene (HDPE) is correct:** The repetitive motion of the metal femoral head against the polyethylene liner produces microscopic wear particles. These particles (specifically those sized 0.1–10 μm) are phagocytosed by **macrophages**. This triggers an inflammatory cascade involving the release of cytokines (IL-1, IL-6, TNF-α) and RANKL. This process leads to **osteoclast activation**, resulting in periprosthetic bone resorption (osteolysis) and subsequent loosening of the implant. 2. **Analysis of Incorrect Options:** * **Titanium debris:** While metal debris can cause "metallosis," polyethylene wear is the dominant cause of osteolysis in conventional cemented THR. * **N,N-Dimethyltryptamine (DMT):** This is a hallucinogenic drug and has no clinical relevance to orthopaedic implants or aseptic loosening. (Note: The chemical used in bone cement is Methylmethacrylate; DMT is likely a distractor for N,N-dimethyl-p-toluidine, an accelerator in cement). * **Free radicals:** While oxidative stress occurs during inflammation, they are secondary products and not the primary inciting agent for the hypersensitivity/osteolytic response. **Clinical Pearls for NEET-PG:** * **Interface:** In cemented THR, loosening most commonly occurs at the **cement-bone interface**. * **Gold Standard:** The most effective way to reduce polyethylene wear is the use of **Highly Cross-Linked Polyethylene (HXLPE)**. * **Radiographic Sign:** Look for "linear osteolysis" or "lucent lines" >2mm wide around the prosthesis (Gruen zones for femur, DeLee and Charnley zones for acetabulum).
Question 10: The Watson-Jones approach is indicated for which of the following conditions?
- A. Neglected club foot
- B. Muscle paralysis
- C. Valgus deformity
- D. Hip replacement (Correct Answer)
Explanation: The **Watson-Jones approach** is a classic **anterolateral approach** to the hip joint. It utilizes the internervous plane between the **Tensor Fasciae Latae (TFL)**, supplied by the Superior Gluteal Nerve, and the **Gluteus Medius**, also supplied by the Superior Gluteal Nerve (though they are technically in the same nerve group, the plane is functional and anatomical). ### Why Hip Replacement is Correct This approach provides excellent exposure of the acetabulum and the femoral neck. It is frequently used for **Total Hip Arthroplasty (THA)**, hemiarthroplasty, and internal fixation of femoral neck fractures. Its primary advantage is a lower rate of posterior dislocation compared to the posterior (Moore’s) approach, as the posterior capsule remains intact. ### Why Other Options are Incorrect * **Neglected Club Foot:** This requires soft tissue releases (like the Turco’s procedure) or bony procedures (like Triple Arthrodesis or Ilizarov) involving the foot and ankle, not the hip. * **Muscle Paralysis:** While surgical releases or tendon transfers are used in paralytic conditions (e.g., Polio or CP), the Watson-Jones is a specific surgical *access* route for the joint, not a corrective procedure for paralysis itself. * **Valgus Deformity:** Genu valgum (at the knee) is typically corrected via medial closing wedge or lateral opening wedge osteotomies around the knee, not through a hip approach. ### High-Yield Clinical Pearls for NEET-PG * **Internervous Plane:** Watson-Jones is often described as "intermuscular" but not strictly "internervous" in some texts because both muscles are supplied by the **Superior Gluteal Nerve**. * **Patient Position:** Usually performed in the lateral or supine position. * **Comparison:** Unlike the **Smith-Petersen (Anterior) approach**, which uses the plane between Sartorius (Femoral n.) and TFL (SGN), the Watson-Jones is more lateral. * **Complication:** The most common nerve at risk during this approach is the **Superior Gluteal Nerve**, which can lead to a Trendelenburg gait if damaged.
Practice by Chapter
Principles of Joint Replacement
Practice Questions
Total Hip Arthroplasty
Practice Questions
Total Knee Arthroplasty
Practice Questions
Shoulder Arthroplasty
Practice Questions
Elbow Arthroplasty
Practice Questions
Ankle Arthroplasty
Practice Questions
Revision Arthroplasty
Practice Questions
Implant Materials and Design
Practice Questions
Complications of Arthroplasty
Practice Questions
Infected Arthroplasty Management
Practice Questions
Rehabilitation After Arthroplasty
Practice Questions
Long-term Outcomes and Surveillance
Practice Questions
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free