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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 7 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 121

Topic: 3. Adult Reconstruction (Hip & Knee)

A 15-year-old girl has severe hip pain 3 years after a slipped capital femoral epiphysis that was complicated by avascular necrosis. Recommended treatment is a hip arthrodesis. In response to questions about late effects, after surgery the patient should be told that she is most likely to experience:

. Low back pain
. Marked limitation of activity
. Pain in the contralateral hip
. C ontinued severe pain in the ipsilateral hip
. Significant continued limp

Correct Answer & Explanation

. Low back pain

Explanation

Low back pain, followed closely by ipsilateral knee pain, is the most common late effect of hip arthrodesis in young patients. The tolerable pain usually occurs much later but may be treated by conversion to arthroplasty, if needed. Ipsilateral hip pain should be minimal or absent if the fusion is successful. Activity following arthrodesis is not significantly limited. Sports and heavy physical activities are feasible. The limp is usually minimal because the loss of hip motion is masked by lumbar motion. Pain in the contralateral hip is rare and is often minimal after hip arthrodesis.

Question 122

Topic: Total Hip Arthroplasty (THA)

A 6-year-old boy has an enlarged right lower extremity compared to the left. Examination reveals a lateral port-wine stain and extensive superficial varicose veins. If his projected leg length discrepancy at skeletal maturity is 3 cm, what is the most appropriate initial orthopedic management?

. Immediate femoral shortening
. Contralateral epiphysiodesis timed appropriately before skeletal maturity
. Amputation and prosthetic fitting
. Ipsilateral femoral lengthening using an Ilizarov frame
. Observation with elastic compression stockings only

Correct Answer & Explanation

. Contralateral epiphysiodesis timed appropriately before skeletal maturity

Explanation

This patient has Klippel-Trenaunay syndrome, characterized by the triad of a capillary malformation (port-wine stain), venous malformations, and soft tissue/bony hypertrophy. A predicted limb length discrepancy of 2 to 5 cm at maturity is best treated with a timed contralateral epiphysiodesis.

Question 123

Topic: 3. Adult Reconstruction (Hip & Knee)

A 4-year-old girl has unilateral idiopathic avascular necrosis involving the entire femoral head. Sixty percent of the height of the lateral column is resorbed. There is no lateral subluxation or physeal disturbance. The range of abduction is 30°. Recommended treatment consists of:

. Observation
. Atlanta Scottish Rite orthosis
. Femoral osteotomy
. Iliac osteotomy
. Petrie cast

Correct Answer & Explanation

. Observation

Explanation

The young age is the overwhelmingly positive factor in this patient. None of the findings mandate a more vigorous approach than observation. The Atlanta Scottish Rite orthosis has not been proven to have any effect on the disorder. Femoral osteotomy would only be possibly indicated, if there were subluxation greater than 25%. Iliac osteotomy would only be indicated in this age group, if there were subluxation and/or other poor prognostic factors. Petrie cast is indicated only if the patient has subluxation.

Question 124

Topic: 3. Adult Reconstruction (Hip & Knee)
A 13-year-old girl has hip pain and the inability to bear weight. On anteroposterior and lateral hip radiographs the femoral head is displaced inferiorly and posteriorly by 50% of its diameter. Recommended treatment includes:
. Closed reduction and immobilization in a spica cast
. Traction followed by internal fixation
. Open reduction and pin fixation
. Metaphyseal osteotomy and internal fixation
. In situ fixation with screw(s)

Correct Answer & Explanation

. In situ fixation with screw(s)

Explanation

In situ fixation has results superior to any of the other methods. Besides being extremely cumbersome, spica cast treatment carries significant risk of redisplacement and chondrolysis. There is no indication for traction in this situation. The amount of displacement can be accepted as long as it is stabilized. Metaphyseal osteotomy carries a risk of avascular necrosis. It should only be undertaken in grade III slips.

Question 125

Topic: 3. Adult Reconstruction (Hip & Knee)

During a total knee arthroplasty, the surgeon notes the knee is tight in flexion and well-balanced in extension. Which of the following adjustments is most appropriate to balance the knee?

. Increase distal femoral resection
. Decrease posterior tibial slope
. Downsize the femoral component
. Resect more proximal tibia
. Release the posterior capsule

Correct Answer & Explanation

. Downsize the femoral component

Explanation

A knee that is tight in flexion but balanced in extension requires an isolated increase in the flexion gap. Downsizing the femoral component (using anterior referencing) decreases the posterior condylar offset, thereby opening the flexion gap without affecting the extension gap.

Question 126

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old woman undergoes revision total hip arthroplasty. Intraoperatively, there is complete separation of the superior and inferior hemipelvis through the acetabulum, confirming pelvic discontinuity. Which of the following is the most appropriate acetabular reconstruction option?

. Standard hemispherical porous cup
. Cemented polyethylene liner directly into the cavitary defect
. Cup-cage construct or custom triflange acetabular component
. Impaction bone grafting alone
. Resection arthroplasty (Girdlestone procedure)

Correct Answer & Explanation

. Cup-cage construct or custom triflange acetabular component

Explanation

Pelvic discontinuity requires rigid fixation bridging the superior and inferior halves of the pelvis. A cup-cage construct, custom triflange, or pelvic distraction with a highly porous jumbo cup are the accepted treatments of choice to provide structural stability.

Question 127

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty for a severe fixed varus deformity, sequential medial soft tissue release is required to balance the knee. After the removal of all medial osteophytes, which structure is classically released first?

. Superficial medial collateral ligament (MCL)
. Deep medial collateral ligament (MCL)
. Semimembranosus insertion
. Pes anserinus
. Posterior cruciate ligament (PCL)

Correct Answer & Explanation

. Deep medial collateral ligament (MCL)

Explanation

In a classic stepwise medial release for a fixed varus knee, medial osteophytes are excised first because they often tent the MCL. If the knee remains tight, the first soft tissue structure released is the deep medial collateral ligament, specifically its meniscotibial attachment.

Question 128

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman presents with severe lateral hip pain and an unremitting limp 2 years after a total hip arthroplasty via a direct lateral approach. Physical examination reveals a profound Trendelenburg lurch. MRI with metal suppression demonstrates a massive, retracted tear of the gluteus medius and minimus tendons with fatty infiltration. What is the most appropriate surgical management?

. Physical therapy and corticosteroid injections
. Endoscopic abductor tendon repair
. Gluteus maximus muscle flap transfer
. Revision to a constrained acetabular liner
. Trochanteric advancement osteotomy

Correct Answer & Explanation

. Gluteus maximus muscle flap transfer

Explanation

For chronic, massive, retracted abductor tendon tears with fatty infiltration post-THA, primary repair is often doomed to fail. A gluteus maximus muscle flap transfer or Achilles tendon allograft reconstruction is the procedure of choice to restore function.

Question 129

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old woman is undergoing a total hip arthroplasty (THA). Which of the following bearing surface combinations is associated with the lowest linear wear rate but carries a risk of catastrophic component fracture?

. Cobalt-chrome on highly cross-linked polyethylene
. Ceramic on ceramic
. Ceramic on conventional polyethylene
. Oxinium on highly cross-linked polyethylene
. Cobalt-chrome on cobalt-chrome

Correct Answer & Explanation

. Ceramic on ceramic

Explanation

Ceramic-on-ceramic bearing surfaces provide the lowest linear wear rates among THA options. However, their primary disadvantage is the risk of catastrophic brittle fracture of the ceramic components.

Question 130

Topic: 3. Adult Reconstruction (Hip & Knee)

During a posterior-stabilized total knee arthroplasty (TKA), the surgeon uses spacer blocks and notes that the knee is tight in flexion but well-balanced in extension. Which of the following is the most appropriate next step to balance the knee?

. Release the posterior cruciate ligament
. Upsize the femoral component
. Resect more distal femur
. Downsize the femoral component
. Release the posterior capsule

Correct Answer & Explanation

. Downsize the femoral component

Explanation

If the knee is tight in flexion but balanced in extension, downsizing the femoral component will increase the flexion gap by reducing the posterior condylar offset, without altering the extension gap.

Question 131

Topic: 3. Adult Reconstruction (Hip & Knee)

A 28-year-old male sustains a displaced fracture of the proximal pole of the scaphoid. The predominant blood supply to the scaphoid, which determines its risk for avascular necrosis, enters primarily through which of the following areas?

. Proximal pole
. Dorsal ridge
. Volar tubercle
. Scapholunate interosseous ligament
. Radioscaphocapitate ligament

Correct Answer & Explanation

. Dorsal ridge

Explanation

The primary blood supply to the scaphoid enters through the dorsal ridge at the waist and flows in a retrograde fashion to the proximal pole. This retrograde flow is why proximal pole fractures have a high rate of avascular necrosis.

Question 132

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following total hip arthroplasty bearing surfaces is associated with the lowest linear wear rate?

. Cobalt-chrome on highly cross-linked polyethylene
. Ceramic on ceramic
. Ceramic on highly cross-linked polyethylene
. Cobalt-chrome on conventional polyethylene
. Oxinium on conventional polyethylene

Correct Answer & Explanation

. Ceramic on ceramic

Explanation

Ceramic-on-ceramic bearings have the lowest linear and volumetric wear rates of all available articulations. However, they carry risks of squeaking and catastrophic ceramic fracture.

Question 133

Topic: 3. Adult Reconstruction (Hip & Knee)

Following a total knee arthroplasty, a patient exhibits a persistent lateral patellar tilt and subluxation. Which of the following technical errors is most likely responsible?

. Internal rotation of the femoral component
. External rotation of the tibial component
. Lateralization of the femoral component
. Medialization of the patellar component
. Excessive valgus cut of the distal femur

Correct Answer & Explanation

. Internal rotation of the femoral component

Explanation

Internal rotation of the femoral or tibial components increases the Q-angle and leads to lateral patellar maltracking. To optimize patellar tracking, the femoral component is typically placed in slight external rotation (e.g., 3 degrees).

Question 134

Topic: Total Hip Arthroplasty (THA)

A 1-year-old girl presents with a right lower extremity abnormality. Her parents report that she has been attempting to stand, but she has not yet walked. C linically, she has a stiff, flexed, varus right knee with an obvious leg length discrepancy. Her ankle is also in a varus position. She does not spontaneously flex or extend the knee from its flexed position. Radiographs show that she has complete tibial hemimelia. The best choice of treatment at this time for the condition is:

. Observation
. Syme amputation
. Limb lengthening
. Knee disarticulation
. Brown procedure

Correct Answer & Explanation

. Knee disarticulation

Explanation

Knee disarticulation eliminates the malformed knee and ankle, allows the use of a prosthesis at an early age to promote ambulation development, and has good long-term results. Observation is a poor option due to the severity of the deformity and the need for treatment to develop ambulation. Syme's amputation does not address the deformity of the knee. In general, joint malformation or instability precludes lengthening procedures. The Brown procedure centralizes the fibula at the knee and includes a Syme's amputation for the abnormal ankle. However, a functioning quadriceps is a prerequisite and there is a high likelihood of flexion contracture postoperatively.

Question 135

Topic: 3. Adult Reconstruction (Hip & Knee)

Positioning of the humeral stem at the time of total shoulder arthroplasty should allow congruent articulation with the glenoid component. C ongruent articulation occurs in most shoulders with a humeral stem positioned in:

. Neutral version
. 10° to 20° of retroversion
. 20° to 30° of retroversion
. 10° to 20° of anteversion
. 20° to 30° of anteversion

Correct Answer & Explanation

. 20° to 30° of retroversion

Explanation

It is important to place the humeral stem in appropriate version to "mate" with the glenoid component. This is most often represented by 20° to 30° of humeral retroversion.

Question 136

Topic: 3. Adult Reconstruction (Hip & Knee)

During a standard posterior approach to the hip for total hip arthroplasty, the surgeon meticulously detaches the short external rotators. Which specific muscle is typically left intact to protect the medial femoral circumflex artery (MFCA)?

. Piriformis
. Obturator internus
. Superior gemellus
. Quadratus femoris
. Gluteus maximus

Correct Answer & Explanation

. Quadratus femoris

Explanation

The quadratus femoris is typically preserved or only partially released during a posterior approach to protect the medial femoral circumflex artery. The MFCA courses highly predictably just deep to the proximal border of this muscle.

Question 137

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty (TKA), the surgeon balances the knee but finds it is extremely tight in flexion while remaining perfectly balanced in extension. Which intraoperative adjustment is most appropriate to resolve this issue?

. Resect more distal femur
. Downsize the femoral component
. Resect more proximal tibia
. Increase the thickness of the polyethylene insert
. Release the posterior capsule

Correct Answer & Explanation

. Downsize the femoral component

Explanation

When the flexion gap is tight but the extension gap is balanced, downsizing the femoral component reduces the posterior condylar offset. This increases the flexion gap space without altering the extension gap.

Question 138

Topic: 3. Adult Reconstruction (Hip & Knee)
In total hip arthroplasty, the use of highly cross-linked polyethylene (HXLPE) liners compared to conventional ultra-high-molecular-weight polyethylene (UHMWPE) is associated with which of the following biomechanical tradeoffs?
. Decreased wear rates but decreased fatigue strength and increased risk of fracture
. Increased wear rates but decreased risk of catastrophic liner fracture
. Decreased wear rates and increased resistance to oxidation without secondary processing
. Higher incidence of component squeaking and metallosis
. Increased risk of osteolysis due to larger particle size generation

Correct Answer & Explanation

. Decreased wear rates but decreased fatigue strength and increased risk of fracture

Explanation

Highly cross-linked polyethylene significantly reduces volumetric wear and subsequent osteolysis. However, the cross-linking and subsequent thermal remelting processes decrease its yield and fatigue strength, slightly increasing the risk of mechanical failure or rim fracture.

Question 139

Topic: Total Knee Arthroplasty (TKA)

Which of the following anatomic and biomechanical factors is most strongly associated with an increased risk of primary anterior cruciate ligament (ACL) injury and subsequent graft failure after reconstruction?

. Decreased Q angle
. Narrow intercondylar notch width
. Increased posterior tibial slope
. Medial meniscus deficiency
. Increased femoral anteversion

Correct Answer & Explanation

. Increased posterior tibial slope

Explanation

An increased posterior tibial slope (typically greater than 12 degrees) is a significant biomechanical risk factor for native ACL injury and reconstruction failure. It increases anterior tibial translation and places higher stress on the ACL graft under axial loading.

Question 140

Topic: 3. Adult Reconstruction (Hip & Knee)

During a total knee arthroplasty (TKA), the popliteal artery is at the greatest risk for iatrogenic injury during which of the following steps?

. Releasing the superficial medial collateral ligament
. Resecting the posterior cruciate ligament or making the posterior tibial bone cut
. Performing a lateral retinacular release
. Removing the anterior osteophytes from the distal femur
. Everting the patella and preparing the patellar surface

Correct Answer & Explanation

. Resecting the posterior cruciate ligament or making the posterior tibial bone cut

Explanation

The popliteal artery lies immediately posterior to the posterior joint capsule of the knee. It is at highest risk of injury during posterior capsular releases, resection of the PCL, or when making the posterior tibial bone cut if retractors are not appropriately placed.

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