Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 199 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 3961

Topic: 3. Adult Reconstruction (Hip & Knee)

A 58-year-old woman with a metal-on-metal total hip arthroplasty presents with a growing, painless groin mass and progressive limping. MRI with MARS reveals a large cystic mass communicating with the joint. What is the most appropriate definitive management?

. CT-guided aspiration
. Revision to a metal-on-polyethylene bearing with synovectomy
. Observation with serial MRIs
. Isolated head and liner exchange using the same bearing surface
. Intravenous antibiotics and irrigation

Correct Answer & Explanation

. Revision to a metal-on-polyethylene bearing with synovectomy

Explanation

The patient has a symptomatic pseudotumor (ALVAL) secondary to metal wear debris from a metal-on-metal articulation. Definitive treatment requires revision of the bearing surfaces to non-metal-on-metal (e.g., metal-on-polyethylene) and thorough excision of the necrotic tissue.

Question 3962

Topic: Total Hip Arthroplasty (THA)

A 72-year-old woman presents with severe groin pain 10 years after THA. Radiographs show a medialized acetabular component with a fracture line through the Kohler line and inferior translation of the lower half of the hemipelvis. What is the most appropriate classification and treatment concept for this defect?

. Paprosky 2B treated with a jumbo cup
. Pelvic discontinuity treated with a cup-cage construct or custom triflange
. Paprosky 3A treated with porous metal augments
. Paprosky 1 treated with impaction grafting
. Protrusio acetabuli treated with bone grafting and a standard cup

Correct Answer & Explanation

. Pelvic discontinuity treated with a cup-cage construct or custom triflange

Explanation

Pelvic discontinuity occurs when the superior and inferior halves of the hemipelvis are separated, marked by a transverse fracture line and medial/inferior translation. Management requires rigid fixation spanning the defect, often utilizing a cup-cage construct, custom triflange, or distraction using a highly porous jumbo cup.

Question 3963

Topic: Total Hip Arthroplasty (THA)

A patient experiences recurrent posterior dislocations of their total hip arthroplasty, especially when rising from a low chair. Radiographic evaluation shows the acetabular component is placed in 25 degrees of anteversion and 40 degrees of inclination. The femoral stem is retroverted by 10 degrees. What is the primary cause of instability?

. Acetabular cup retroversion
. Femoral stem retroversion
. Acetabular cup under-inclination
. Impingement from excess femoral offset
. Insufficient abductor tension

Correct Answer & Explanation

. Femoral stem retroversion

Explanation

Combined anteversion (acetabular plus femoral) should fall safely between 25 and 45 degrees. A retroverted femoral stem (-10 degrees) combined with 25 degrees of cup anteversion results in insufficient overall anteversion, predisposing the hip to posterior dislocation during flexion.

Question 3964

Topic: Total Hip Arthroplasty (THA)
Which of the following patients with osteonecrosis of the femoral head is the most appropriate candidate for core decompression?
. A 45-year-old with a 2 mm crescent sign on radiographs
. A 30-year-old with pre-collapse stage II disease involving 20% of the weight-bearing area
. A 50-year-old with femoral head collapse of 4 mm and secondary osteoarthritis
. A 60-year-old with stage IV disease
. A 35-year-old with stage III disease and subchondral fracture

Correct Answer & Explanation

. A 30-year-old with pre-collapse stage II disease involving 20% of the weight-bearing area

Explanation

Core decompression is most successful in early, pre-collapse osteonecrosis (Ficat Stage I or II) with small to medium-sized lesions. Once subchondral fracture (crescent sign, Stage III) or overt collapse (Stage IV) occurs, the failure rate is high, and THA is typically indicated.

Question 3965

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old man with a dual-mobility total hip arthroplasty presents with acute hip pain and a grinding sensation after a fall. Radiographs show an eccentric position of the small femoral head within the large acetabular shell. What is the most likely diagnosis?

. Wear of the metallic acetabular shell
. Intra-prosthetic dislocation (IPD)
. Aseptic loosening of the cup
. Trunnionosis
. Subluxation of the entire dual-mobility bearing

Correct Answer & Explanation

. Intra-prosthetic dislocation (IPD)

Explanation

Intra-prosthetic dislocation (IPD) is a unique complication of dual-mobility bearings where the small inner femoral head dissociates from the large mobile polyethylene liner. Radiographically, it presents as an asymmetric, eccentric position of the femoral head within the outer shell.

Question 3966

Topic: 3. Adult Reconstruction (Hip & Knee)



A 75-year-old sustains a fall 3 years after a cementless THA. Radiographs show a periprosthetic femur fracture around the distal aspect of the stem. The stem is radiographically loose with subsidence, but there is excellent proximal and distal bone stock. According to the Vancouver classification, what is the standard recommended treatment?

. Open reduction and internal fixation with cables and a locking plate
. Revision to a long cementless fully porous-coated or fluted tapered stem
. Revision to a proximal femoral replacement (tumor prosthesis)
. Nonoperative management with a brace
. Cortical strut allografting alone

Correct Answer & Explanation

. Revision to a long cementless fully porous-coated or fluted tapered stem

Explanation

A fracture around a loose stem with adequate bone stock is classified as a Vancouver B2 periprosthetic fracture. The gold standard treatment is revision to a longer cementless stem (often fluted and tapered) that bypasses the fracture site to achieve diaphyseal fixation.

Question 3967

Topic: Total Hip Arthroplasty (THA)

During a posterior approach to the hip, what is the key anatomical structure that serves as the posterior border of the gluteus medius and protects the superior gluteal neurovascular bundle from injury?

. Piriformis
. Quadratus femoris
. Gluteus minimus
. Tensor fasciae latae
. Superior gemellus

Correct Answer & Explanation

. Piriformis

Explanation

The superior gluteal neurovascular bundle exits the greater sciatic foramen superior to the piriformis muscle. Identifying the piriformis and avoiding dissection more than 3-5 cm proximal to its insertion minimizes the risk of injury to the superior gluteal nerve.

Question 3968

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old active male is undergoing a total hip arthroplasty (THA). The surgeon selects a ceramic-on-ceramic bearing to maximize longevity. Which of the following is a unique clinical complication most specific to this bearing surface compared to ceramic-on-polyethylene?

. Catastrophic failure of the femoral stem
. Audible squeaking during ambulation
. Trunnionosis with elevated serum cobalt
. Accelerated acetabular osteolysis
. Galvanic corrosion at the head-neck junction

Correct Answer & Explanation

. Audible squeaking during ambulation

Explanation

Ceramic-on-ceramic bearings carry a unique risk of audible squeaking, often associated with edge loading due to component malposition (e.g., steep cup angle). While ceramic is highly wear-resistant, squeaking can lead to patient dissatisfaction and, rarely, indicates impending catastrophic ceramic fracture.

Question 3969

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old female presents with severe thigh pain 4 years after a cementless THA. Radiographs in Figure 4 demonstrate a spiral fracture around the femoral stem with obvious subsidence of the implant. According to the Vancouver classification, what is the most appropriate management?

. Open reduction and internal fixation with cables and a plate
. Nonoperative management with strict protected weight-bearing
. Revision of the femoral component using a long cementless stem
. Distal femoral replacement
. Removal of hardware and application of an external fixator

Correct Answer & Explanation

. Revision of the femoral component using a long cementless stem

Explanation

This is a Vancouver B2 periprosthetic fracture, characterized by a fracture around the stem with a loose implant but adequate bone stock. The standard of care is revision arthroplasty using a long, porous-coated cementless stem that bypasses the fracture by at least two cortical diameters.

Question 3970

Topic: Total Hip Arthroplasty (THA)

A 55-year-old woman complains of new-onset severe groin pain with active straight leg raise 1 year after an uncomplicated THA. A diagnostic injection of bupivacaine into the psoas bursa under ultrasound guidance completely relieves her pain. What is the most likely radiographic finding associated with this condition?

. Superior migration of the acetabular component
. Retroverted position of the femoral stem
. Anterior overhang of the acetabular component
. Posterior uncoverage of the acetabular cup
. Excessive combined anteversion

Correct Answer & Explanation

. Anterior overhang of the acetabular component

Explanation

Iliopsoas impingement post-THA is classic for pain with active hip flexion and relief following a psoas bursa injection. It is most commonly caused by an anteriorly prominent or overhanging acetabular component rubbing against the iliopsoas tendon.

Question 3971

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 8 shows the radiograph of a 72-year-old female undergoing revision THA. Intraoperatively, she is found to have complete dissociation between the superior and inferior halves of the hemipelvis. Which of the following is the most appropriate acetabular reconstruction technique?

. Standard hemispherical jumbo cementless cup
. Impaction bone grafting with a cemented polyethylene liner
. Bipolar hemiarthroplasty articulating on native bone
. Cup-cage construct or custom triflange component
. Resection arthroplasty (Girdlestone procedure)

Correct Answer & Explanation

. Cup-cage construct or custom triflange component

Explanation

The scenario describes pelvic discontinuity, an advanced form of acetabular bone loss (Paprosky IV). Reconstruction requires mechanical stabilization across the discontinuity, typically achieved with a cup-cage construct, custom triflange, or a distraction technique using highly porous metal components.

Question 3972

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient presents with unexplained groin pain and soft tissue swelling 5 years after receiving a metal-on-metal THA. Laboratory analysis reveals significantly elevated serum cobalt levels but normal serum chromium levels. This isolated elevation is most indicative of:

. Trunnionosis (head-neck taper corrosion)
. Catastrophic wear of the acetabular bearing surface
. Impingement of the femoral neck on the acetabular cup
. Galvanic corrosion at the stem-cement interface
. Aseptic loosening of the femoral stem

Correct Answer & Explanation

. Trunnionosis (head-neck taper corrosion)

Explanation

An elevated serum cobalt level with a normal or disproportionately low chromium level is the hallmark laboratory finding of mechanically assisted crevice corrosion (MACC), or trunnionosis, at the modular head-neck junction.

Question 3973

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 11 displays a hip resurfacing arthroplasty. According to current guidelines, which of the following is considered an absolute contraindication for this specific procedure?

. Male gender
. Primary osteoarthritis
. Cysts involving greater than 50% of the femoral head
. Avascular necrosis with less than 10% head involvement
. A history of slipped capital femoral epiphysis

Correct Answer & Explanation

. Cysts involving greater than 50% of the femoral head

Explanation

Hip resurfacing requires adequate femoral head and neck bone stock for fixation. Extensive cystic changes (greater than 50% involvement), renal failure, known metal allergy, and severe osteoporosis are absolute contraindications.

Question 3974

Topic: Total Hip Arthroplasty (THA)

A 68-year-old man undergoes a primary right THA. At his 6-week postoperative visit, he complains his right leg feels "too long." Clinical exam reveals level anterior superior iliac spines (ASIS) with block testing, but the patient perceives a prominent discrepancy. What is the most appropriate initial management?

. Reassurance and observation for up to 6 months
. Immediate prescription for a contralateral shoe lift
. Revision surgery to exchange the femoral head for a shorter neck
. Botulinum toxin injection into the abductor musculature
. Contralateral total hip arthroplasty

Correct Answer & Explanation

. Reassurance and observation for up to 6 months

Explanation

Perceived leg length discrepancy is common in the early postoperative period following THA due to pelvic obliquity and muscle contractures. If true leg lengths are equal (level ASIS on block testing), reassurance and physical therapy are indicated, as the perception typically resolves within 6 months.

Question 3975

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary THA for post-traumatic osteoarthritis, the surgeon notes a history of extensive heterotopic ossification (HO) following the initial trauma. To prevent HO recurrence, the patient is prescribed radiation therapy. What is the optimal timing for this prophylactic radiation?

. 1 week prior to surgery
. Within 24 hours preoperatively or up to 72 hours postoperatively
. 1 week postoperatively
. Continuous low-dose fractionated therapy for 2 weeks
. Radiation is contraindicated if cementless implants are used

Correct Answer & Explanation

. Within 24 hours preoperatively or up to 72 hours postoperatively

Explanation

Prophylactic radiation therapy for heterotopic ossification is most effective when administered either within 24 hours before surgery or within 72 hours after surgery. A single dose of 700 to 800 cGy is the standard regimen.

Question 3976

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old man develops acute, severe hip pain 3 weeks after an uncomplicated primary THA. Joint aspiration yields a white blood cell count of 35,000 cells/uL with 92% neutrophils. Radiographs show a well-fixed stem and cup. What is the currently recommended surgical treatment?

. One-stage revision of all components
. Two-stage exchange arthroplasty with an antibiotic spacer
. Debridement, antibiotics, and implant retention (DAIR) with modular exchange
. Intravenous suppressive antibiotics alone
. Resection arthroplasty (Girdlestone)

Correct Answer & Explanation

. Debridement, antibiotics, and implant retention (DAIR) with modular exchange

Explanation

In cases of early acute periprosthetic joint infection (typically within 4 weeks of index surgery) with stable implants, DAIR (Debridement, Antibiotics, and Implant Retention) along with polyethylene liner exchange is the treatment of choice to eradicate infection while preserving the implants.

Question 3977

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 17 demonstrates a hip MRI of a 40-year-old patient with a history of high-dose corticosteroid use. The MRI shows a geographic, serpiginous band in the anterosuperior femoral head without subchondral collapse (Ficat Stage II). What is the most appropriate joint-preserving surgical intervention?

. Core decompression
. Total hip arthroplasty
. Hemiarthroplasty
. Proximal femoral osteotomy
. Arthroscopic labral repair

Correct Answer & Explanation

. Core decompression

Explanation

Ficat Stage II avascular necrosis (AVN) is characterized by cystic/sclerotic changes on radiographs and MRI evidence of AVN, but without subchondral collapse or joint space narrowing. Core decompression is the standard joint-preserving procedure to reduce intraosseous pressure and promote revascularization at this stage.

Question 3978

Topic: Total Hip Arthroplasty (THA)

An 80-year-old patient with advanced Parkinson's disease requires a primary THA for severe osteoarthritis. To minimize the significant risk of postoperative dislocation in this specific patient population, which acetabular component design modification is most appropriate?

. High wall polyethylene liner
. Constrained polyethylene liner
. Standard 28 mm modular femoral head
. Dual mobility articulation
. Ceramic-on-ceramic bearing

Correct Answer & Explanation

. Dual mobility articulation

Explanation

Patients with neuromuscular disorders like Parkinson's disease are at high risk for dislocation. Dual mobility articulations significantly increase the jump distance and range of motion before impingement, effectively reducing dislocation rates without the high mechanical failure rates associated with constrained liners.

Question 3979

Topic: Total Hip Arthroplasty (THA)

A patient presents with a severe limp, lateral hip pain, and a positive Trendelenburg sign 6 months after a primary THA performed via a direct lateral (Hardinge) approach. An MRI with metal artifact reduction sequence (MARS) confirms a massive, full-thickness avulsion of the gluteus medius and minimus tendons. What is the most appropriate management?

. Physical therapy focusing on core strengthening
. Abductor tendon repair, potentially with allograft augmentation
. Revision to a constrained acetabular liner
. Botulinum toxin injection to the iliopsoas
. Trochanteric osteotomy and distal advancement

Correct Answer & Explanation

. Abductor tendon repair, potentially with allograft augmentation

Explanation

A recognized complication of the direct lateral approach is failure of the abductor repair. A massive, symptomatic full-thickness tear resulting in a severe Trendelenburg gait requires surgical repair of the abductor mechanism, often utilizing allograft or synthetic augmentation if tissue quality is poor.

Question 3980

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following total hip arthroplasty bearing surface combinations is most strongly associated with the postoperative complication of squeaking?

. Metal-on-polyethylene
. Ceramic-on-polyethylene
. Ceramic-on-ceramic
. Metal-on-metal
. Oxinium-on-polyethylene

Correct Answer & Explanation

. Ceramic-on-ceramic

Explanation

Squeaking is a unique complication associated predominantly with ceramic-on-ceramic bearings. It is often linked to component malposition, microseparation, or edge loading, which disrupts the fluid film lubrication.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page