Adult Reconstructive Surgery of the Hip and Knee Scored and
Recorded Self-Assessment Examination 2024
,Question 1
What factor is associated with a higher risk of dislocation after total hip arthroplasty?
A. Male gender
B. Previous hip surgery
C. A direct lateral surgical approach
D. Metal-on-metal bearing surfaces
CORRECT ANSWER : B
DISCUSSION:
Dislocation after total hip arthroplasty is a multifactorial problem. Numerous risk factors may act
independently or cumulatively to increase the risk of this complication. Previous hip surgery of any kind
is associated with a twofold increased risk for dislocation. Other risk factors include female gender,
impaired mental status, inflammatory arthritis, and older age. Numerous studies have shown a lower
dislocation rate with a direct lateral approach, although surgical techniques such as capsular repair have
significantly lowered the incidence of dislocation after using the posterior approach. Metal-on-metal
bearings have been associated with other complications such as adverse tissue reactions but are often used
with larger-diameter bearings, which pose a lower risk of dislocation.
Question 2
A patient has pain 2 years after undergoing a metal-on-metal (MOM) left total hip arthroplasty (THA). Which
test(s) best correlate with a prognosis if this patient is having a reaction to metal debris?
A. Erythrocyte sedimentation rate, C-reactive protein, and white blood cell count
B. Serum cobalt and chromium ion levels
C. MRI with metal artifact reduction sequence (MARS)
D. CT of pelvis
CORRECT ANSWER: C
DISCUSSION:
Painful MOM THA and taper corrosion can cause substantial damage to a patient's hip if left untreated.
In this case, the workup for a painful MOM THA starts the same as a workup for a painful metal-on-
polyethylene bearing couple. Infection must be ruled out in every case with a set of inflammatory markers.
If these markers are remotely elevated, this is an indication for joint aspiration. In patients with metal
debris, the pathology report often indicates too many cells to count or cellular debris. Metal ion levels do
not seem to correlate with prognosis. There are well-functioning patients with high ion levels and poor-
functioning patients with low ion levels. Advanced imaging with MARS MRI to evaluate for
peritrochanteric fluid collection, a soft-tissue mass, or synovial/capsular hypertrophy will reveal signs of
a metal reaction that indicate the need for a revision discussion. A CT scan can show more advanced bony
destruction as an indicator of poor prognosis. These films can be used to determine the need for a structural
graft or augments for reconstruction of bone loss attributable to metal debris.
Question 3
Figures below demonstrate the radiographs obtained from a 35-year-old woman with end-stage
debilitating osteoarthritis of the right hip. She is contemplating total hip arthroplasty (THA). She has a
history of right hip dysplasia and underwent hip osteotomy as an adolescent. Over the years, nonsurgical
treatment, including weight loss, activity modifications, and intra-articular injections, has failed. Her
infection work-up reveals laboratory findings within defined limits. A further work-up reveals elevations
in serum cobalt and chromium levels and fluid collections surrounding the hip on MRI with MARS.
Revision THA is recommended. The most common complication following revision of a failed metal-on-
metal hip arthroplasty is
, A. infection.
B. instability.
C. loosening.
D. periprosthetic fracture.
CORRECT ANSWER: B
DISCUSSION:
THA has proven durable and reliable for pain relief and improving function for patients with end-stage
arthritis. Appropriate bearing selection is critical to minimize wear and hip complications. A metal-on-
metal articulation is associated with excellent wear rates in vitro. With its capacity to offer a low wear
rate with large femoral heads, it is an attractive bearing choice for THA. However, local soft-tissue
reactions, pseudotumors, and potential systemic reactions including renal failure, cardiomyopathy,
carcinogenesis, and potential teratogenesis with potential transfer of metal ions across the placental barrier
make metal-on-metal bearings less desirable and relatively contraindicated for younger women of child-
bearing age. The workup of a painful metal-on-metal hip arthroplasty necessitates a systematic approach.
Several algorithms have been proposed. Routine laboratory studies including sedimentation rate, CRP,
and serum cobalt and chromium ion levels should be obtained for all patients with pain. Advanced
imaging including MARS MRI should be performed to evaluate for the presence of fluid collections,
pseudotumors, and abductor mechanism destruction. Infection can coexist with metal-on-metal reactions,
so, when indicated (if the CRP level is elevated), a hip arthrocentesis should be obtained. However, in
this setting, a manual cell count and differential should be obtained because an automated cell counter
may provide falsely elevated cellcounts. The results of revision surgery for a failed metal-on-metal hip
prosthesis can be variable. The amount of local tissue destruction and the integrity of the hip abductor
mechanism can greatly influence outcomes. Instability is the most common complication following
revision of failed metal-on-metal hip replacements.
Question 4
Figure 1 shows the radiograph and Figure 2 shows the MRI scan obtained from a 37-year-old woman with a
2-month history of left hip pain. Which combination of a single symptom and examination finding is most
likely in this scenario?
, A. Pain during sitting; flexion abduction and external rotation of the hip
B. Groin pain; pain with internal rotation and adduction while supine with the hip and knee flexed 90°
C. Clicking; abductor lurch
D. Buttock pain; pain with hip extension, adduction, and external rotation while prone
CORRECT ANSWER: B
DISCUSSION:
MRI areveals aan aanterior alabral atear, aand athe aradiograph ashows aminimal aarthritis awith apossible
adysplasia. aThe amost acommon alocation aof apain ain apatients awith aa alabral atear ais athe agroin, aand athe
amost acommon aphysical afinding ais aa apositive aimpingement atest aresult. aPain aduring asitting, aclicking,
aand abuttock apain aare afrequently adescribed aby apatients awith aa alabral atear, abut athese asymptoms aare
aless acommon athan agroin apain. aA a positive a posterior a impingement a test a finding a is a more
a common a in a patients a with a a a posterior a labral atear. aAlthough aage aover a40 ayears aand aa abody
amass aindex ahigher athan a30 acan aadversely aaffect aclinical aoutcomes aafter ajoint apreservation
aprocedures asuch aas aPAO, ahip aarthroscopy, aand afemoral aacetabular aimpingement asurgery, athe
apresence aof ahip aarthritis aon apresurgical aradiographs ais athe amost acommonly amentioned acause aof
afailed ahip ajoint apreservation asurgery. aTönnis agrade ais aa aradiographic ameasure aof ahip aarthritis. aA
ahigher aOuterbridge ascore ais aassociated awith amore afrequent apoor aoutcomes aafter ahip aarthroscopy;
ahowever, athe aOuterbridge acartilage ascore ais adetermined aby adirect avisualization aat athe atime aof
asurgery. aThe aOuterbridge ascore acannot abe adetermined apresurgically.
aQuestion a5
aFigures a1 aand a2 ademonstrate athe aradiographs aobtained afrom aa a35-year-old awoman awith aend-stage
adebilitating aosteoarthritis aof athe aright ahip. aShe ais acontemplating atotal ahip aarthroplasty a(THA). aShe
ahas aa ahistory aof aright ahip adysplasia aand aunderwent ahip aosteotomy aas aan aadolescent. aOver athe
ayears, anonsurgical atreatment, aincluding aweight aloss, aactivity amodifications, aand aintra-articular
ainjections, ahas afailed. aHer ainfection awork-up areveals alaboratory afindings awithin adefined alimits.The
apatient aundergoes asuccessful aprimary aTHA awith aa ametal-on-metal abearing. aAt a1-year afollow-up,
ashe areports ano apain aand ais ahighly asatisfied awith athe aprocedure. aHowever, a3 ayears aafter athe aindex
aprocedure, ashe areports aatraumatic aright ahip apain athat aworsens awith aactivities. aRadiographs areveal
athe aimplants ain agood aposition awith ano asign aof aloosening aor alysis. aAn ainitial alaboratory aevaluation
areveals aa anormal asedimentation arate aand aC-reactive aprotein a(CRP) alevel. aThe amost aappropriate
anext adiagnostic astep ais
A. MRI with metal artifact reduction sequence (MARS) only.
B. serum cobalt only.
C. serum cobalt and chromium levels.
D. serum cobalt and chromium levels and MRI with MARS.
CORRECT aANSWER: aD
aDISCUSSION:
THA ahas aproven ato abe adurable aand areliable afor apain arelief aand aimprovement aof afunction ain
apatients awith aend-stage a arthritis. a Appropriate a bearing a selection a is a critical a to a minimize a wear a and
Recorded Self-Assessment Examination 2024
,Question 1
What factor is associated with a higher risk of dislocation after total hip arthroplasty?
A. Male gender
B. Previous hip surgery
C. A direct lateral surgical approach
D. Metal-on-metal bearing surfaces
CORRECT ANSWER : B
DISCUSSION:
Dislocation after total hip arthroplasty is a multifactorial problem. Numerous risk factors may act
independently or cumulatively to increase the risk of this complication. Previous hip surgery of any kind
is associated with a twofold increased risk for dislocation. Other risk factors include female gender,
impaired mental status, inflammatory arthritis, and older age. Numerous studies have shown a lower
dislocation rate with a direct lateral approach, although surgical techniques such as capsular repair have
significantly lowered the incidence of dislocation after using the posterior approach. Metal-on-metal
bearings have been associated with other complications such as adverse tissue reactions but are often used
with larger-diameter bearings, which pose a lower risk of dislocation.
Question 2
A patient has pain 2 years after undergoing a metal-on-metal (MOM) left total hip arthroplasty (THA). Which
test(s) best correlate with a prognosis if this patient is having a reaction to metal debris?
A. Erythrocyte sedimentation rate, C-reactive protein, and white blood cell count
B. Serum cobalt and chromium ion levels
C. MRI with metal artifact reduction sequence (MARS)
D. CT of pelvis
CORRECT ANSWER: C
DISCUSSION:
Painful MOM THA and taper corrosion can cause substantial damage to a patient's hip if left untreated.
In this case, the workup for a painful MOM THA starts the same as a workup for a painful metal-on-
polyethylene bearing couple. Infection must be ruled out in every case with a set of inflammatory markers.
If these markers are remotely elevated, this is an indication for joint aspiration. In patients with metal
debris, the pathology report often indicates too many cells to count or cellular debris. Metal ion levels do
not seem to correlate with prognosis. There are well-functioning patients with high ion levels and poor-
functioning patients with low ion levels. Advanced imaging with MARS MRI to evaluate for
peritrochanteric fluid collection, a soft-tissue mass, or synovial/capsular hypertrophy will reveal signs of
a metal reaction that indicate the need for a revision discussion. A CT scan can show more advanced bony
destruction as an indicator of poor prognosis. These films can be used to determine the need for a structural
graft or augments for reconstruction of bone loss attributable to metal debris.
Question 3
Figures below demonstrate the radiographs obtained from a 35-year-old woman with end-stage
debilitating osteoarthritis of the right hip. She is contemplating total hip arthroplasty (THA). She has a
history of right hip dysplasia and underwent hip osteotomy as an adolescent. Over the years, nonsurgical
treatment, including weight loss, activity modifications, and intra-articular injections, has failed. Her
infection work-up reveals laboratory findings within defined limits. A further work-up reveals elevations
in serum cobalt and chromium levels and fluid collections surrounding the hip on MRI with MARS.
Revision THA is recommended. The most common complication following revision of a failed metal-on-
metal hip arthroplasty is
, A. infection.
B. instability.
C. loosening.
D. periprosthetic fracture.
CORRECT ANSWER: B
DISCUSSION:
THA has proven durable and reliable for pain relief and improving function for patients with end-stage
arthritis. Appropriate bearing selection is critical to minimize wear and hip complications. A metal-on-
metal articulation is associated with excellent wear rates in vitro. With its capacity to offer a low wear
rate with large femoral heads, it is an attractive bearing choice for THA. However, local soft-tissue
reactions, pseudotumors, and potential systemic reactions including renal failure, cardiomyopathy,
carcinogenesis, and potential teratogenesis with potential transfer of metal ions across the placental barrier
make metal-on-metal bearings less desirable and relatively contraindicated for younger women of child-
bearing age. The workup of a painful metal-on-metal hip arthroplasty necessitates a systematic approach.
Several algorithms have been proposed. Routine laboratory studies including sedimentation rate, CRP,
and serum cobalt and chromium ion levels should be obtained for all patients with pain. Advanced
imaging including MARS MRI should be performed to evaluate for the presence of fluid collections,
pseudotumors, and abductor mechanism destruction. Infection can coexist with metal-on-metal reactions,
so, when indicated (if the CRP level is elevated), a hip arthrocentesis should be obtained. However, in
this setting, a manual cell count and differential should be obtained because an automated cell counter
may provide falsely elevated cellcounts. The results of revision surgery for a failed metal-on-metal hip
prosthesis can be variable. The amount of local tissue destruction and the integrity of the hip abductor
mechanism can greatly influence outcomes. Instability is the most common complication following
revision of failed metal-on-metal hip replacements.
Question 4
Figure 1 shows the radiograph and Figure 2 shows the MRI scan obtained from a 37-year-old woman with a
2-month history of left hip pain. Which combination of a single symptom and examination finding is most
likely in this scenario?
, A. Pain during sitting; flexion abduction and external rotation of the hip
B. Groin pain; pain with internal rotation and adduction while supine with the hip and knee flexed 90°
C. Clicking; abductor lurch
D. Buttock pain; pain with hip extension, adduction, and external rotation while prone
CORRECT ANSWER: B
DISCUSSION:
MRI areveals aan aanterior alabral atear, aand athe aradiograph ashows aminimal aarthritis awith apossible
adysplasia. aThe amost acommon alocation aof apain ain apatients awith aa alabral atear ais athe agroin, aand athe
amost acommon aphysical afinding ais aa apositive aimpingement atest aresult. aPain aduring asitting, aclicking,
aand abuttock apain aare afrequently adescribed aby apatients awith aa alabral atear, abut athese asymptoms aare
aless acommon athan agroin apain. aA a positive a posterior a impingement a test a finding a is a more
a common a in a patients a with a a a posterior a labral atear. aAlthough aage aover a40 ayears aand aa abody
amass aindex ahigher athan a30 acan aadversely aaffect aclinical aoutcomes aafter ajoint apreservation
aprocedures asuch aas aPAO, ahip aarthroscopy, aand afemoral aacetabular aimpingement asurgery, athe
apresence aof ahip aarthritis aon apresurgical aradiographs ais athe amost acommonly amentioned acause aof
afailed ahip ajoint apreservation asurgery. aTönnis agrade ais aa aradiographic ameasure aof ahip aarthritis. aA
ahigher aOuterbridge ascore ais aassociated awith amore afrequent apoor aoutcomes aafter ahip aarthroscopy;
ahowever, athe aOuterbridge acartilage ascore ais adetermined aby adirect avisualization aat athe atime aof
asurgery. aThe aOuterbridge ascore acannot abe adetermined apresurgically.
aQuestion a5
aFigures a1 aand a2 ademonstrate athe aradiographs aobtained afrom aa a35-year-old awoman awith aend-stage
adebilitating aosteoarthritis aof athe aright ahip. aShe ais acontemplating atotal ahip aarthroplasty a(THA). aShe
ahas aa ahistory aof aright ahip adysplasia aand aunderwent ahip aosteotomy aas aan aadolescent. aOver athe
ayears, anonsurgical atreatment, aincluding aweight aloss, aactivity amodifications, aand aintra-articular
ainjections, ahas afailed. aHer ainfection awork-up areveals alaboratory afindings awithin adefined alimits.The
apatient aundergoes asuccessful aprimary aTHA awith aa ametal-on-metal abearing. aAt a1-year afollow-up,
ashe areports ano apain aand ais ahighly asatisfied awith athe aprocedure. aHowever, a3 ayears aafter athe aindex
aprocedure, ashe areports aatraumatic aright ahip apain athat aworsens awith aactivities. aRadiographs areveal
athe aimplants ain agood aposition awith ano asign aof aloosening aor alysis. aAn ainitial alaboratory aevaluation
areveals aa anormal asedimentation arate aand aC-reactive aprotein a(CRP) alevel. aThe amost aappropriate
anext adiagnostic astep ais
A. MRI with metal artifact reduction sequence (MARS) only.
B. serum cobalt only.
C. serum cobalt and chromium levels.
D. serum cobalt and chromium levels and MRI with MARS.
CORRECT aANSWER: aD
aDISCUSSION:
THA ahas aproven ato abe adurable aand areliable afor apain arelief aand aimprovement aof afunction ain
apatients awith aend-stage a arthritis. a Appropriate a bearing a selection a is a critical a to a minimize a wear a and
