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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 12 of 326

This practice set contains high-yield board review questions covering key concepts in 3. Adult Reconstruction (Hip & Knee). Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 221

Topic: 3. Adult Reconstruction (Hip & Knee)

During extraction of a well-fixed porous-coated cementless acetabular cup, which instrument is best utilized to minimize host bone loss?

. Cobb elevator
. Explant system (curved osteotomes)
. High-speed burr
. Gigli saw
. Slap hammer

Correct Answer & Explanation

. Explant system (curved osteotomes)

Explanation

The Explant system or similar curved, hemispherical osteotomes are designed to precisely match the outer contour of the cup. They cut the bone-implant interface efficiently while preserving maximal host acetabular bone.

Question 222

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old male with an uncemented fully porous-coated cylindrical stem placed 10 years ago presents with new onset thigh pain. Radiographs show 5mm of stem subsidence and a radiolucent line around the entire porous coated region, but thick cortical hypertrophy at the stem tip. What does this indicate?

. Stress shielding
. Proximal loosening with distal pedestal formation and stable fibrous fixation
. Proximal loosening with rigid distal point fixation
. Impending femoral shaft fracture
. Periprosthetic joint infection

Correct Answer & Explanation

. Proximal loosening with distal pedestal formation and stable fibrous fixation

Explanation

Subsidence of a fully porous-coated stem with complete proximal radiolucencies and distal cortical hypertrophy indicates a loss of proximal ingrowth with rigid distal point fixation. This mismatch often leads to thigh pain and eventual mechanical failure.

Question 223

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female sustains a fall 5 years after THA. Radiographs reveal a periprosthetic femur fracture that occurs entirely distal to the tip of a well-fixed cemented femoral stem. Based on the Vancouver classification, what is the type and typical treatment?

. Type B1; open reduction and internal fixation with a plate and cables
. Type B2; revision to a long-stem prosthesis
. Type B3; proximal femoral replacement
. Type C; open reduction and internal fixation with an overlapping plate
. Type A; non-operative management

Correct Answer & Explanation

. Type C; open reduction and internal fixation with an overlapping plate

Explanation

A fracture entirely distal to the tip of a well-fixed femoral component is a Vancouver Type C fracture. The standard treatment is ORIF, ensuring the fixation construct overlaps the distal aspect of the stem to prevent stress risers.

Question 224

Topic: Total Hip Arthroplasty (THA)

During revision THA for a superiorly migrated and loose acetabular component, restoring the anatomic hip center of rotation is crucial. Placing the hip center of rotation superiorly and laterally rather than at its anatomic position will result in which of the following biomechanical effects?

. Decreased joint reaction force
. Increased abductor moment arm
. Increased joint reaction force and decreased abductor efficiency
. Decreased risk of dislocation
. Improved leg length equality

Correct Answer & Explanation

. Increased joint reaction force and decreased abductor efficiency

Explanation

A superior and lateral hip center decreases the abductor moment arm and increases the body weight moment arm. This leads to a significantly increased joint reaction force, accelerating wear and decreasing abductor efficiency.

Question 225

Topic: Total Hip Arthroplasty (THA)

A 28-year-old male suffers a T11 fracture-dislocation with complete paraplegia (ASIA A) 24 hours post-injury. During surgical stabilization, what is the most important factor in determining the likelihood of his neurologic recovery?

. The timing of surgery within 8 hours
. The initial severity of the neurologic deficit (complete vs incomplete)
. The choice of anterior versus posterior approach
. Administration of high-dose methylprednisolone
. The type of bone graft used for fusion

Correct Answer & Explanation

. The initial severity of the neurologic deficit (complete vs incomplete)

Explanation

In spinal cord injury, the most significant prognostic factor for neurologic recovery is the completeness of the initial injury. Patients with a complete deficit (ASIA A) have a very low probability of significant functional motor recovery.

Question 226

Topic: 3. Adult Reconstruction (Hip & Knee)
A patient requires acetabular revision THA. Radiographs demonstrate >3 cm of superior migration of the hip center, disruption of the Kohler line, and severe ischial osteolysis. Intraoperatively, there is <30% remaining host bone contact for a hemispherical component. Which of the following is the most appropriate reconstructive option?
. A jumbo hemispherical porous cup alone
. Impaction bone grafting with a cemented cup
. A custom triflange acetabular component or cup-cage construct
. An anti-protrusio cage with cancellous autograft
. A standard uncemented cup with multiple screws

Correct Answer & Explanation

. A custom triflange acetabular component or cup-cage construct

Explanation

This describes a Paprosky type IIIB defect or pelvic discontinuity with massive bone loss. Such severe defects with inadequate host bone for biological fixation are best treated with a custom triflange component or cup-cage construct to achieve initial mechanical stability.

Question 227

Topic: 3. Adult Reconstruction (Hip & Knee)
In evaluating a patient who underwent a primary THA 10 years ago, what is the recognized threshold for linear wear rate of ultra-high-molecular-weight polyethylene (UHMWPE) above which the risk of periprosthetic osteolysis significantly increases?
. 0.01 mm/year
. 0.05 mm/year
. 0.10 mm/year
. 0.50 mm/year
. 1.00 mm/year

Correct Answer & Explanation

. 0.10 mm/year

Explanation

Periprosthetic osteolysis is strongly associated with volumetric polyethylene wear. The critical threshold for linear wear rate leading to clinically significant osteolysis is classically described as >0.10 mm/year.

Question 228

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old male with a metal-on-metal total hip arthroplasty presents 8 years postoperatively with a painful, enlarging groin mass. Serum cobalt and chromium levels are elevated. MRI reveals a large cystic fluid collection with thick walls communicating with the joint. What is the primary histological feature of this condition?

. Extensive neutrophil infiltration with intracellular bacteria
. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)
. Massive histiocytic infiltration with polyethylene wear debris
. Malignant spindle cells with high mitotic figures
. Granulomatous inflammation with caseating necrosis

Correct Answer & Explanation

. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)

Explanation

Adverse local tissue reactions (ALTR) or pseudotumors in metal-on-metal implants are histologically characterized by an Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesion (ALVAL), representing a delayed type IV hypersensitivity reaction to metal ions.

Question 229

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old female undergoes a revision THA for aseptic loosening. Preoperative radiographs demonstrate a transverse radiolucent line across the acetabulum and a break in the ilioischial line. Intraoperatively, the superior and inferior hemipelvis are found to move independently. Which of the following is the most appropriate acetabular reconstruction strategy?

. Impaction bone grafting with a cemented polyethylene cup
. Placement of a standard jumbo hemispherical multi-hole titanium cup
. Use of a cup-cage construct or custom triflange acetabular component
. High hip center placement of a standard cementless cup
. Resection arthroplasty (Girdlestone procedure)

Correct Answer & Explanation

. Use of a cup-cage construct or custom triflange acetabular component

Explanation

This patient has a pelvic discontinuity. Stable fixation requires bypassing the discontinuity to bridge the ilium and ischium, typically achieved with a cup-cage construct, custom triflange, or a distraction approach with highly porous metal.

Question 230

Topic: 3. Adult Reconstruction (Hip & Knee)

When performing an extended trochanteric osteotomy (ETO) for the extraction of a well-fixed cementless femoral stem during revision THA, what is the biomechanical requirement for the diaphyseal fit of the new revision stem?

. The revision stem should end exactly at the distal aspect of the ETO to prevent stress shielding.
. The revision stem must bypass the most distal aspect of the osteotomy by at least two cortical bone diameters (approximately 4-6 cm).
. The ETO must be limited to less than 8 cm in length to allow use of a primary stem.
. The revision stem must be fully cemented into the diaphysis to secure the osteotomy.
. The revision stem requires proximal porous coating only, relying entirely on the ETO cables for distal stability.

Correct Answer & Explanation

. The revision stem must bypass the most distal aspect of the osteotomy by at least two cortical bone diameters (approximately 4-6 cm).

Explanation

To ensure adequate stability and prevent periprosthetic fractures at the tip, the revision stem must achieve an interference fit in the intact diaphysis, bypassing the distal extent of the ETO by at least two cortical diameters.

Question 231

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old male sustains a periprosthetic femur fracture around a loose THA stem. Radiographs demonstrate severe proximal femoral bone loss, with osteolysis extending to the isthmus and extremely poor remaining bone stock (Vancouver B3). What is the most reliable surgical treatment option for this patient?

. Open reduction and internal fixation with a locking plate
. Revision to a standard cementless tapered stem
. Proximal femoral replacement (megaprosthesis)
. Impaction bone grafting with a standard cemented stem
. Revision to an extensively porous-coated stem using solely cortical strut allografts

Correct Answer & Explanation

. Proximal femoral replacement (megaprosthesis)

Explanation

Vancouver B3 fractures involve a loose stem with severely deficient bone stock. In elderly or low-demand patients, a proximal femoral replacement allows for early weight-bearing and is the most reliable option.

Question 232

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male with a metal-on-polyethylene THA presents with new-onset groin pain. Radiographs are normal. A MARS MRI shows a thick-walled cystic mass communicating with the joint. Serum cobalt levels are markedly elevated, while chromium is normal. What is the most likely etiology?

. Delayed-onset periprosthetic joint infection
. Mechanically assisted crevice corrosion at the head-neck taper (trunnionosis)
. Polyethylene wear-induced osteolysis
. Impingement of the iliopsoas tendon over the acetabular rim
. Aseptic loosening of the acetabular component

Correct Answer & Explanation

. Mechanically assisted crevice corrosion at the head-neck taper (trunnionosis)

Explanation

Elevated cobalt with normal chromium in a metal-on-polyethylene THA, combined with an adverse local tissue reaction (ALTR) mass, is the hallmark of mechanically assisted crevice corrosion at the trunnion.

Question 233

Topic: 3. Adult Reconstruction (Hip & Knee)
According to the Paprosky classification of acetabular defects, which of the following best defines a Type IIIB defect?
. Less than 2 cm of superior migration with an intact teardrop.
. Superior migration greater than 3 cm with an intact Kohler's line.
. Superior migration greater than 3 cm with severe medial migration indicating a broken Kohler's line.
. Pelvic discontinuity with an intact posterior column.
. Isolated ischial osteolysis without superior migration.

Correct Answer & Explanation

. Superior migration greater than 3 cm with severe medial migration indicating a broken Kohler's line.

Explanation

A Paprosky Type IIIB defect is characterized by severe superomedial migration of the hip center (>3 cm superiorly) and severe destruction of the medial wall (broken Kohler's line/ilioischial line).

Question 234

Topic: 3. Adult Reconstruction (Hip & Knee)

During revision THA for an adverse local tissue reaction (ALTR) caused by severe head-neck taper corrosion, the femoral stem is found to be well-fixed and correctly positioned. What is the recommended strategy regarding the femoral stem?

. Retain the stem and place a new cobalt-chrome head.
. Retain the stem and place a ceramic head using a titanium adapter sleeve.
. Extract the stem using an extended trochanteric osteotomy.
. Perform a complete excision arthroplasty (Girdlestone).
. Retain the stem and place an oversized stainless-steel head.

Correct Answer & Explanation

. Retain the stem and place a ceramic head using a titanium adapter sleeve.

Explanation

To minimize morbidity, a well-fixed stem can be retained. A ceramic head with a titanium sleeve is used to bypass the damaged trunnion and eliminate further metal-on-metal corrosion.

Question 235

Topic: Total Hip Arthroplasty (THA)

A 70-year-old female with recurrent THA dislocations due to abductor deficiency is planned for revision. The existing acetabular shell is a well-fixed, correctly positioned multi-hole titanium cup. Which of the following is the most appropriate surgical intervention to restore stability?

. Cementation of a dual mobility liner into the existing well-fixed shell
. Use of a standard constrained liner in the existing shell without cement
. Extraction of the well-fixed shell and placement of a tri-flange component
. Placement of a 36-mm cobalt-chrome head directly into the titanium shell
. Use of a standard polyethylene liner with an elevated 10-degree rim

Correct Answer & Explanation

. Cementation of a dual mobility liner into the existing well-fixed shell

Explanation

Cementing a dual mobility liner into a well-fixed compatible titanium shell provides excellent stability for recurrent instability and avoids the morbidity of extracting a well-ingrown cup.

Question 236

Topic: Total Hip Arthroplasty (THA)

A surgeon is utilizing a posterior approach to the humerus for open reduction and internal fixation of a midshaft fracture. To properly access the posterior humerus while minimizing damage to the triceps innervation, the superficial dissection utilizes an internervous or intermuscular plane. Which of the following describes the correct superficial interval for this approach?

. Between the brachialis and the brachioradialis
. Between the medial head and lateral head of the triceps
. Between the long head and lateral head of the triceps
. Between the anconeus and the extensor carpi ulnaris
. Between the brachioradialis and the extensor carpi radialis longus

Correct Answer & Explanation

. Between the long head and lateral head of the triceps

Explanation

The superficial interval in the posterior approach to the humerus is between the lateral and long heads of the triceps. Deep to this, the medial head is split longitudinally to expose the humeral shaft, avoiding the radial nerve which spirals proximally.

Question 237

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old patient underwent silicone arthroplasty of the index finger PIP joint for erosive osteoarthritis 3 years ago. She now presents with increasing pain, instability, and a palpable click in the joint. Radiographs show evidence of implant fracture and subluxation. She is a high-demand individual who relies heavily on her index finger for pinch and grip. What is the most common and reliable salvage strategy for this failed PIP arthroplasty, especially for the index finger?

. Revision silicone arthroplasty with a larger implant.
. Conversion to pyrocarbon arthroplasty, if bone stock allows.
. Collateral ligament reconstruction and continued splinting.
. Conversion to arthrodesis.
. Long-term corticosteroid injections and activity modification.

Correct Answer & Explanation

. Conversion to arthrodesis.

Explanation

Correct Answer: DThe 'Complications & Management' section, under 'Salvage Strategies' for 'Failed Arthroplasty (Instability, Fracture, Infection),' states: 'The most common and reliable salvage for a failed PIP arthroplasty, especially for the index finger, is conversion to arthrodesis. This provides stability and pain relief at the cost of motion.' The patient's high demand for pinch and grip further supports arthrodesis, as stability is prioritized for the index finger.Incorrect Options:A:Revision silicone arthroplasty is generally not recommended for failed silicone implants, especially in high-demand joints like the index finger, due to the inherent limitations and high failure rates of silicone prostheses under significant load.B:While conversion to pyrocarbon arthroplasty may be considered in select cases if bone stock allows, the case content notes it 'carries higher risks' and that arthrodesis is 'the most common and reliable salvage,' particularly for the index finger where stability is paramount.C:Collateral ligament reconstruction alone would not address the implant fracture and subluxation, and would likely be insufficient to restore stability in a failed arthroplasty.E:Long-term corticosteroid injections and activity modification are conservative measures that have already failed in the initial treatment and are unlikely to salvage a mechanically failed arthroplasty with implant fracture and subluxation.

Question 238

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old patient undergoes arthrodesis of the index finger PIP joint for severe erosive osteoarthritis. Post-operatively, a dorsal splint is applied, maintaining the fused PIP joint in 35 degrees of flexion. Which of the following is the most appropriate initial post-operative rehabilitation instruction for this patient during the first 4-6 weeks?

. Initiate active and passive range of motion exercises for the fused PIP joint immediately.
. Begin gentle progressive strengthening exercises for the entire hand, including the fused PIP joint.
. Strictly avoid any active or passive motion at the fused PIP joint, while encouraging active and passive ROM for adjacent MCP and DIP joints.
. Remove the splint daily for wound care and full range of motion exercises of the PIP joint.
. Apply continuous dynamic extension splinting to prevent flexion contracture of the PIP joint.

Correct Answer & Explanation

. Strictly avoid any active or passive motion at the fused PIP joint, while encouraging active and passive ROM for adjacent MCP and DIP joints.

Explanation

Correct Answer: CThe 'Post-Operative Rehabilitation Protocols' section, under 'Following PIP Arthrodesis,' states for 'Immobilization (0-6 weeks)': 'Strictly avoid any active or passive motion at the fused PIP joint.' It also states for 'Early Mobilization (0-6 weeks)': 'Active and passive range of motion exercises for the MCP and DIP joints of the operated finger, as well as the adjacent fingers, are encouraged immediately to prevent stiffness.' This aligns perfectly with option C.Incorrect Options:A & B:Initiating active/passive ROM or strengthening for the fused PIP joint immediately would jeopardize the fusion site and risk non-union. The goal is rigid immobilization of the PIP joint.D:While wound care is important, removing the splint daily for full PIP ROM exercises would compromise the fusion. The splint is typically worn continuously until early fusion is evident.E:Dynamic extension splinting is typically used after arthroplasty to assist with extension and prevent flexion contractures, where motion is desired. For arthrodesis, the goal is fusion, and the joint is immobilized in a static position.

Question 239

Topic: 3. Adult Reconstruction (Hip & Knee)

A 59-year-old female presents with severe pain and deformity of her index finger PIP joint due to erosive osteoarthritis. She is a retired librarian and prioritizes a stable, pain-free joint for activities like reading and light gardening. Radiographs show significant joint destruction. After a thorough discussion of options, the surgeon recommends arthrodesis. According to the current consensus and literature, which of the following statements best supports the choice of arthrodesis for the index finger PIP joint in this patient?

. Arthroplasty offers superior long-term pain relief and durability compared to arthrodesis for the index PIP joint.
. Silicone arthroplasty is the preferred method for the index PIP due to its excellent motion preservation and low complication rates.
. Arthrodesis provides a highly reliable, stable, and pain-free joint, which is often prioritized for the index finger due to its role in pinch and grip.
. Pyrocarbon arthroplasty is universally recommended for all index PIP EOA patients due to its anatomical design and improved kinematics.
. Arthrodesis is associated with higher rates of non-union and persistent pain compared to modern arthroplasty techniques for the index PIP.

Correct Answer & Explanation

. Arthrodesis provides a highly reliable, stable, and pain-free joint, which is often prioritized for the index finger due to its role in pinch and grip.

Explanation

Correct Answer: CThe 'Summary of Key Literature / Guidelines' section, under 'Current Consensus,' states: 'For severe, painful, and deforming EOA of the index finger PIP joint refractory to conservative management: 1. Arthrodesis remains a highly reliable option, especially for patients prioritizing stability, pain relief, and strength for pinch and grip. It is generally the preferred option for the index finger PIP joint among many hand surgeons.' This directly supports the choice of arthrodesis for this patient who prioritizes stability and pain relief for her activities.Incorrect Options:A:The literature review indicates that arthrodesis consistently reports high fusion rates and excellent pain relief, while arthroplasty outcomes for the index finger PIP can be less predictable, with concerns regarding implant durability and reoperation rates, especially for silicone.B:Silicone arthroplasty is generally less favored for the index PIP due to higher failure rates in this high-demand digit, as stated in the literature review.D:While pyrocarbon arthroplasty is a viable alternative, it is not universally recommended. The consensus emphasizes that the decision must be individualized, and arthrodesis is often preferred for the index finger.E:The literature review states that arthrodesis consistently reports high fusion rates (85-95%) and excellent pain relief, making this statement incorrect. While non-union is a known complication, its rates are generally manageable, and arthrodesis is considered highly reliable.

Question 240

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old female presents with acute, severe pain and swelling in her index finger PIP joint, diagnosed with an acute flare of erosive osteoarthritis. Radiographs show early joint space narrowing and minimal osteophyte formation, without significant erosions or collapse. She has no fixed deformity and good range of motion. Which of the following is the most appropriate initial management strategy?

. Immediate surgical arthrodesis to prevent further progression.
. Immediate surgical pyrocarbon arthroplasty to preserve motion.
. Intra-articular corticosteroid injection, NSAIDs, splinting, and hand therapy.
. Long-term systemic immunosuppressive therapy.
. Referral for psychological support due to chronic pain.

Correct Answer & Explanation

. Intra-articular corticosteroid injection, NSAIDs, splinting, and hand therapy.

Explanation

Correct Answer: CThe 'Indications & Contraindications' section, under 'Non-Operative Indications,' lists 'Early disease: Minimal joint destruction, mild to moderate pain, preserved range of motion, and absence of significant deformity' and 'Acute flares: Intense pain and swelling during inflammatory episodes' as indications for non-operative management. The 'Summary of Key Literature / Guidelines' further supports this, stating: 'First-line treatment generally involves NSAIDs for pain and inflammation, activity modification, splinting for support and pain relief during flares, and hand therapy to maintain range of motion and strength. Intra-articular corticosteroid injections can provide temporary relief during acute inflammatory episodes.' This patient's presentation of an acute flare with early disease and preserved function aligns perfectly with this conservative approach.Incorrect Options:A & B:Immediate surgical intervention (arthrodesis or arthroplasty) is reserved for failed conservative management, significant functional impairment, or advanced deformity/destruction, none of which are present in this early stage acute flare.D:Long-term systemic immunosuppressive therapy is typically reserved for systemic inflammatory arthropathies like rheumatoid arthritis or psoriatic arthritis, not generally for EOA, which is primarily managed locally and symptomatically.E:While psychological support can be beneficial for chronic pain, it is not the primary initial management for an acute inflammatory flare of EOA.

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