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Total Hip Arthroplasty (THA) MCQs

Practice Set 13 of 36

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

Question 241

Topic: Total Hip Arthroplasty (THA)

A 44-year-old woman has bilateral knee pain, and history reveals bilateral hip replacements. Radiographs are seen in Figure 28a, and histopathologic specimens from the total hip replacement are shown in Figures 28b and 28c. Laboratory studies reveal anemia. What is the most likely diagnosis?

. Osteoarthritis
. Rheumatoid arthritis
. Pigmented villonodular synovitis
. Charcot arthropathy
. Paget's disease

Correct Answer & Explanation

. Rheumatoid arthritis

Explanation

Rheumatoid arthritis is an inflammatory arthritis that usually involves multiple joints. Radiologic findings of periarticular erosion, osteopenia, and minimal osteophyte formation favor rheumatoid arthritis over osteoarthritis. Pigmented villonodular synovitis and Charcot arthropathy are more often considered monoarticular diseases. There are no radiographic findings of Paget's disease.

Question 242

Topic: Total Hip Arthroplasty (THA)

Figure 29 shows the radiograph of a 55-year-old patient who has recurrent total hip dislocation. Dislocation is most likely to occur in this patient when the hip is in which of the following positions?

Hip Board Review 2001: High-Yield MCQs (Set 4) - Figure 1

. Neutral rotation
. External rotation
. Internal rotation
. Hyperflexion
. Midstance phase of gait

Correct Answer & Explanation

. Internal rotation

Explanation

The patient has an acetabular component that is placed in excessive anteversion; this is confirmed by the shoot-through radiograph. The most common reasons for dislocation of a total hip replacement include inappropriate positioning of the components, inadequate abductor tension, or impingement. Implants placed without adequate total anteversion tend to dislocate posteriorly, and implants with excessive anteversion tend to dislocate anteriorly. Superior dislocations can occur if the acetabular component is placed in a severely vertical position with inadequate lateral coverage.

Question 243

Topic: Total Hip Arthroplasty (THA)

Which of the following is considered an important factor in improved cemented femoral stem survivorship?

. Precoated stem with methylmethacrylate
. Varus stem position
. 2 to 3 mm of circumferential cement mantle
. Dorr C or "stovepipe" femoral anatomy
. Sharp angled corners on the femoral stem

Correct Answer & Explanation

. 2 to 3 mm of circumferential cement mantle

Explanation

Cement technique, relative stem to canal size and position, stem design, surgical technique, and femoral anatomy are important factors in cemented stem survivorship. Varus stem position, a wide diaphyseal to metaphyseal ratio (stovepipe femur), thin cement mantles (1 mm or less), and nonrounded femoral stem designs are negative prognostic factors for stem survivorship. Precoating with methylmethacrylate has not been shown to provide any increased survivorship over nonprecoated stems. Noble PC, Collier MB, Maltry JA, Kamaric E, Tullos HS: Pressurization and centalization enhance the quality and reproducibility of cement mantles. Clin Orthop 1998;355:77-89. Crowninshield RD, Brand RA, Johnston RC, Milroy JC: The effect of femoral stem cross-sectional geometry on cement stresses in total hip reconstruction. Clin Orthop 1980;146:71-77.

Question 244

Topic: Total Hip Arthroplasty (THA)

Design and manufacturing of a metal-on-metal articulation has an important influence on the tribology. Which of the following statements best characterizes the type of contact that is best for metal-on-metal articulations?

. Equatorial contact should exceed polar contact.
. Polar contact should exceed equatorial contact.
. Polar and equatorial contact should be equal by exactly duplicating radii.
. The "bedding in" process makes consideration of polar equatorial contact unimportant.
. The stiffness of metal-on-metal articulations makes consideration of polar equatorial contact unimportant.

Correct Answer & Explanation

. Polar contact should exceed equatorial contact.

Explanation

It is important that the radii of a metal-on-metal head to cup articulation be such that there is polar contact. As the radii become closer to equal, conditions favor higher frictional torque and equatorial seizing. The "bedding in" of metal-on-metal surfaces and their stiffness are both components of the properties considered in the design of polar contact surfaces.

Question 245

Topic: Total Hip Arthroplasty (THA)

Which of the following factors is most closely associated with early postoperative migration of "stand-alone" lumbar interbody fusion cages?

Spine Surgery 2006 Practice Questions: Set 1 (Solved) - Figure 29

. Pseudarthrosis
. Placement of the cage through a posterior approach
. Placement of the cage laparoscopically through an anterior approach
. Use of tapered rather than cylindrical cages
. Use of BMP-2 rather than autograft in the cage

Correct Answer & Explanation

. Placement of the cage through a posterior approach

Explanation

Postoperative migration of lumbar interbody fusion cages is a rare complication. It is most commonly seen after placement of the cages through a posterior approach, with instability of the final construct. It is not associated with the design of the cage, the type of graft used, or a resultant pseudarthrosis. McAfee PC: Interbody fusion cages in reconstructive operations on the spine. J Bone Joint Surg Am 1999;81:859-880.

Question 246

Topic: Total Hip Arthroplasty (THA)

One of the serious potential complications of repair of distal biceps tendon ruptures is limited pronation and supination as a result of synostosis. What surgical approach and technique presents the highest risk for development of this complication?

Upper Extremity 2005 Practice Questions: Set 1 (Solved) - Figure 8

. Single incision, anterior approach with fixation through drill holes in the radius
. Single incision, anterior approach with suture anchor fixation to the radius
. Single incision, anterior approach through a drill hole in the radius with sutures tied over bolster or button on the posterior forearm
. Dual incision, limited anterior and posterior approach along the ulna with attachment through drill holes
. Dual incision, limited anterior and posterior muscle-splitting approach (supinator and extensor muscles) with attachment through drill holes

Correct Answer & Explanation

. Dual incision, limited anterior and posterior muscle-splitting approach (supinator and extensor muscles) with attachment through drill holes

Explanation

The risk of synostosis is imminent with any technique for repairing a distal biceps tendon rupture. However, the risk is quite low for all approaches that avoid exposure of the ulna, including the muscle-splitting two-incision technique.

Question 247

Topic: Total Hip Arthroplasty (THA)

A 55-year-old active female who underwent a ceramic-on-ceramic total hip arthroplasty 2 years ago presents with a loud, audible squeaking during hip flexion. Which of the following is most strongly associated with this complication?

. Use of a larger diameter femoral head
. Femoral stem anteversion of 15 degrees
. Acetabular component retroversion and edge loading
. Failure to use a ceramic liner with a metal rim
. Post-operative heterotopic ossification

Correct Answer & Explanation

. Acetabular component retroversion and edge loading

Explanation

Squeaking in ceramic-on-ceramic THA is a well-documented phenomenon. It is most strongly associated with component malposition—specifically, excessive acetabular cup abduction or retroversion, which leads to edge loading, stripe wear, and microseparation. Patient factors such as high BMI and younger, more active lifestyles also contribute.

Question 248

Topic: Total Hip Arthroplasty (THA)

A 55-year-old active male underwent a total hip arthroplasty using a ceramic-on-ceramic bearing.

He presents 2 years post-operatively complaining of a squeaking noise from the hip during walking. Which of the following component malpositions is most commonly associated with this phenomenon?

. Acetabular component retroversion
. Femoral component retroversion
. Acetabular component edge loading due to excessive inclination
. Excessive femoral offset
. Insufficient acetabular version

Correct Answer & Explanation

. Acetabular component edge loading due to excessive inclination

Explanation

Squeaking in ceramic-on-ceramic THA is often associated with edge loading, which typically results from acetabular component malposition, specifically excessive inclination and/or version issues causing loss of fluid film lubrication and subsequent stripe wear.

Question 249

Topic: Total Hip Arthroplasty (THA)

A 70-year-old patient returns to the emergency department three weeks following an uncomplicated primary total hip arthroplasty (posterior approach) with complaints of sudden severe hip pain. Radiographs demonstrate a posterior dislocation of the femoral component. Closed reduction is successful. In evaluating the cause of this early instability, which of the following component malpositions is the most common etiology for posterior dislocation in THA?

. Acetabular component retroversion
. Acetabular component excessive abduction
. Femoral component excessive anteversion
. Excessive offset reconstruction
. Acetabular component excessive anteversion

Correct Answer & Explanation

. Acetabular component retroversion

Explanation

Instability following THA is multifactorial. However, when component malposition is the primary driver of a posterior dislocation, acetabular retroversion (insufficient anteversion) is the most frequent culprit. Normal acetabular anteversion target is 15-20 degrees. Retroversion impinges the anterior neck during internal rotation/flexion, levering the head out posteriorly. Excessive abduction leads to superior escape/instability. Excessive anteversion usually leads to anterior dislocation.

Question 250

Topic: Total Hip Arthroplasty (THA)

A 72-year-old female is undergoing a primary total hip arthroplasty via a posterior approach. During trial reduction, the hip is found to be highly unstable, dislocating posteriorly when the leg is placed in flexion, adduction, and internal rotation. The surgeon determines the acetabular and femoral components are oriented in perfect native version and inclination, but there is significant soft tissue laxity. The femoral head trial is currently a standard neck (+0). Which of the following component adjustments would most appropriately address this instability?

. Increase the femoral head length (e.g., to +4 or +8)
. Decrease the femoral head length (e.g., to -4)
. Decrease acetabular anteversion
. Decrease femoral anteversion
. Use an elevated rim liner positioned posteroinferiorly

Correct Answer & Explanation

. Increase the femoral head length (e.g., to +4 or +8)

Explanation

In the setting of a posterior approach THA with posterior instability due to soft-tissue laxity (and correctly positioned components), increasing the femoral offset and leg length by using a longer offset head (e.g., +4 or +8) increases myofascial tissue tension, particularly of the abductors and external rotators, thereby stabilizing the hip joint. Decreasing anteversion or head length would worsen posterior instability.

Question 251

Topic: Total Hip Arthroplasty (THA)

A 62-year-old man who underwent a primary ceramic-on-ceramic total hip arthroplasty two years ago presents with an audible 'squeaking' from his hip during normal ambulation. Radiographs show well-fixed components. Which of the following factors is most highly correlated with the development of squeaking in ceramic-on-ceramic bearings?

. Acetabular component placed in excessive anteversion and high inclination
. Decreased femoral offset
. Use of a 36-mm head instead of a 28-mm head
. Acetabular retroversion combined with a varus femoral stem
. Micro-motion of the uncemented femoral stem

Correct Answer & Explanation

. Acetabular component placed in excessive anteversion and high inclination

Explanation

Squeaking in ceramic-on-ceramic total hip arthroplasties is a well-documented phenomenon. It is most strongly associated with component malposition, specifically high acetabular inclination (abduction) and excessive anteversion. This malposition leads to 'edge loading,' where the mechanical contact forces are concentrated on the rim of the ceramic liner. Edge loading disrupts the fluid film lubrication, resulting in stripe wear, increased friction, and the generation of an audible squeak.

Question 252

Topic: Total Hip Arthroplasty (THA)

A 72-year-old male presents with recurrent posterior dislocations following a right total hip arthroplasty performed 2 months ago via a posterior approach. Radiographs show a well-fixed femoral stem and an acetabular component with 10 degrees of anteversion and 45 degrees of abduction. During revision surgery, the acetabular component is found to be solidly ingrown. Which of the following is the most appropriate surgical intervention to prevent further posterior dislocations?

. Increase femoral offset by changing to a longer femoral head.
. Revise the acetabular shell to increase anteversion.
. Apply a constrained acetabular liner into the existing shell.
. Revise the femoral stem to increase anteversion.
. Prescribe an abduction orthosis for 6 weeks.

Correct Answer & Explanation

. Revise the acetabular shell to increase anteversion.

Explanation

The ideal acetabular cup position in total hip arthroplasty is generally considered to be 15 to 20 degrees of anteversion and 40 to 45 degrees of abduction. An anteversion of 10 degrees is relatively retroverted, especially when a posterior approach is used, predisposing the patient to posterior instability. Since the cup is malpositioned, the most appropriate treatment is revision of the acetabular shell to correct the anteversion.

Question 253

Topic: Total Hip Arthroplasty (THA)

A 55-year-old male who underwent a ceramic-on-ceramic total hip arthroplasty 3 years ago reports a new 'squeaking' noise from his hip during specific movements. He denies pain, and radiographs show no gross loosening. Which of the following component position factors is most strongly associated with the development of squeaking in ceramic-on-ceramic bearings?

. Decreased femoral offset
. Excessive acetabular cup anteversion
. Insufficient acetabular cup abduction
. Femoral stem retroversion
. Edge loading due to cup malposition

Correct Answer & Explanation

. Edge loading due to cup malposition

Explanation

Squeaking in ceramic-on-ceramic THA is most strongly associated with edge loading, which often results from cup malposition (such as excessive abduction or extremes of version). Edge loading leads to loss of fluid-film lubrication, stripe wear, and micro-separation during the swing phase, producing the characteristic high-frequency squeak.

Question 254

Topic: Total Hip Arthroplasty (THA)

A 68-year-old female presents with recurrent posterior dislocations following a primary total hip arthroplasty performed 6 months ago.

A recent CT scan evaluating component positioning reveals an acetabular component inclination of 45 degrees and an anteversion of 0 degrees. The femoral stem has 15 degrees of anteversion. What is the most likely underlying cause of her recurrent instability?

. Acetabular retroversion
. Excessive acetabular anteversion
. Excessive femoral stem anteversion
. Vertical inclination of the acetabular component
. Abductor mechanism deficiency

Correct Answer & Explanation

. Acetabular retroversion

Explanation

The 'safe zone' for acetabular component placement, historically described by Lewinnek, is 15° ± 10° of anteversion and 40° ± 10° of inclination. An acetabular anteversion of 0 degrees means the cup is placed in relative retroversion compared to normal native anatomy. Acetabular retroversion heavily predisposes a THA patient to posterior dislocation, particularly when the hip is placed in flexion, adduction, and internal rotation.

Question 255

Topic: Total Hip Arthroplasty (THA)

A 68-year-old female undergoes a primary THA via a posterior approach. Postoperatively, she suffers a posterior dislocation. Which of the following component malpositions most likely contributed to this complication?

. Excessive acetabular anteversion
. Decreased femoral offset
. Excessive acetabular abduction
. Acetabular retroversion
. Excessive femoral anteversion

Correct Answer & Explanation

. Acetabular retroversion

Explanation

Posterior dislocation following THA is most commonly associated with acetabular retroversion or insufficient femoral anteversion. Excessive acetabular anteversion typically leads to anterior dislocation.

Question 256

Topic: Total Hip Arthroplasty (THA)

A 50-year-old active male underwent a THA 3 years ago and now complains of an audible squeaking sound during hip flexion.

Which of the following factors is most strongly associated with squeaking in ceramic-on-ceramic total hip arthroplasty?

. Use of a 28 mm femoral head
. Acetabular component anteversion of 15 degrees
. Component malposition leading to edge loading
. Body mass index > 40
. Use of a highly cross-linked polyethylene liner

Correct Answer & Explanation

. Component malposition leading to edge loading

Explanation

Squeaking is a specific complication associated with hard-on-hard bearings, particularly ceramic-on-ceramic THA. The most significant biomechanical cause is edge loading, which occurs due to micro-separation, impingement, or component malposition (e.g., steep cup abduction angles or insufficient anteversion). This results in loss of fluid film lubrication and stripe wear, ultimately causing the squeak.

Question 257

Topic: Total Hip Arthroplasty (THA)

During a total hip arthroplasty via a posterior approach, the surgeon decides to use a high-offset femoral stem rather than a standard-offset stem. Assuming neck angle and leg length remain constant, what is the primary biomechanical effect of this change?

. Increased abductor tension and decreased joint reactive force
. Decreased abductor tension and increased joint reactive force
. Increased risk of sciatic nerve palsy due to soft tissue stretch
. Decreased femoral component anteversion
. Increased global offset leading to impingement

Correct Answer & Explanation

. Decreased abductor tension and increased joint reactive force

Explanation

Increasing the femoral offset lateralizes the proximal femur. This increases the lever arm (moment arm) of the abductor musculature. Because the abductors have a mechanical advantage, they require less force to balance the pelvis during single-leg stance. A reduction in abductor muscle force proportionally decreases the overall joint reactive force across the hip.

Question 258

Topic: Total Hip Arthroplasty (THA)
A 14-year-old male with a history of slipped capital femoral epiphysis (SCFE) treated with in situ pinning 2 years ago presents with new onset, severe right hip pain and inability to bear weight. Radiographs show no change in the pin position but reveal subtle flattening and sclerosis of the femoral head epiphysis, consistent with avascular necrosis (AVN). What is the most appropriate management strategy for this complication?
. Removal of the in situ pin and observation.
. Core decompression with bone grafting.
. Total hip arthroplasty (THA).
. Intertrochanteric osteotomy to reorient the femoral head.
. Conservative management with protected weight-bearing and NSAIDs.

Correct Answer & Explanation

. Total hip arthroplasty (THA).

Explanation

The patient has developed avascular necrosis (AVN) of the femoral head, a severe complication of SCFE. Radiographic findings of flattening and sclerosis indicate Ficat Stage III or IV, where collapse has occurred. Core decompression is indicated for pre-collapse stages (I or II). Intertrochanteric osteotomy is generally for residual deformity or segmental AVN with preserved cartilage. In a 14-year-old with painful, collapsed AVN, THA is the most definitive option for pain relief and functional restoration, despite concerns regarding implant longevity in young patients.

Question 259

Topic: Total Hip Arthroplasty (THA)

A 62-year-old female presents with recurrent episodes of left hip dislocation following a primary total hip arthroplasty performed 3 months ago via a posterior approach. She has undergone two closed reductions. Clinical examination reveals no leg length discrepancy or neurovascular deficits. Radiographs, shown below, indicate appropriate acetabular and femoral component positioning without evidence of loosening.

Given the recurrent dislocations with well-positioned components, what is the MOST appropriate next surgical management strategy?

. Revision of the acetabular component to a more constrained liner.
. Revision of the femoral component to a larger head size.
. Conversion to a dual-mobility articulation.
. Open reduction and repair of the posterior capsule.
. Abductor advancement and trochanteric osteotomy.

Correct Answer & Explanation

. Conversion to a dual-mobility articulation.

Explanation

The image shows a total hip arthroplasty. The patient has recurrent hip dislocations after THA despite well-positioned components. This scenario often suggests soft tissue laxity or impingement, or an issue with the prosthetic articulation itself. Given the well-positioned components, simply increasing head size or repairing the capsule might not be sufficient to prevent recurrence, especially with a posterior approach where capsular and external rotator repair are crucial.A dual-mobility (DM) articulation is a common and effective solution for recurrent hip instability, particularly when component position is acceptable. It uses a small femoral head that articulates within a larger polyethylene liner, which then articulates within the acetabular cup. This 'ball-within-a-ball' design significantly increases the jumping distance required for dislocation, thereby enhancing stability.Rationale for options:A. Revision to a more constrained liner might increase stability but also significantly increases stress at the liner-shell interface and can lead to early failure or loosening. It is usually reserved for highly unstable hips where other options have failed, or when neuromuscular deficiencies are present.B. Revision of the femoral component to a larger head size can increase jumping distance and stability, and is often considered a first-line solution. However, it may still not be sufficient for recurrent dislocations, especially if there are ongoing soft tissue issues or if the initial head size was already adequate for typical primary THA.C. Conversion to a dual-mobility articulation offers a significant increase in stability and has shown excellent results in reducing dislocation rates in challenging cases, including recurrent dislocations with well-positioned components. It provides a larger 'effective' head size without increasing impingement risks as much as constrained liners. This is often the most appropriate and effective choice for recurrent dislocations when components are well-positioned. This is the correct answer.D. Open reduction and repair of the posterior capsule might be indicated if the original repair was inadequate, but for recurrent dislocations after initial good repair, it may not be sufficient on its own without addressing the articulation.E. Abductor advancement and trochanteric osteotomy might be considered for abductor insufficiency but are not the primary solution for recurrent dislocation from a biomechanical perspective of impingement/jumping distance.

Question 260

Topic: Total Hip Arthroplasty (THA)

A 55-year-old male who underwent a ceramic-on-ceramic total hip arthroplasty 3 years ago presents to the clinic complaining of a loud 'squeaking' sound coming from his hip when he walks. He denies pain. Which of the following component malpositions is most strongly associated with this complication?

. Acetabular cup retroversion
. Femoral stem retroversion
. Steep acetabular cup inclination (vertical placement)
. Insufficient femoral offset

Correct Answer & Explanation

. Steep acetabular cup inclination (vertical placement)

Explanation

Squeaking in ceramic-on-ceramic total hip arthroplasty is a well-documented phenomenon caused by altered tribology. It is most strongly associated with edge loading of the ceramic bearings. Edge loading occurs most frequently when the acetabular cup is placed with excessive steepness (high abduction/inclination angle) or excessive anteversion.

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