2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
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,2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
Question 1-Cementless knee replacements are associated with
1. increased risk for revision.
2. increased wear of the polyethylene insert.
3. increased infection risk.
4. significantly higher Knee Society Scores (KSS).
DISCUSSION-Many published series comparing cementless to cemented knee replacements show
no difference in KSS or infection risk, but data in several registries demonstrate a significant increase
in the revision rates for cementless knees. Although no difference in poly wear occurred, loosening of
the tibial component was the most common cause of failure. PREFERRED RESPONSE: 1
CLINICAL SITUATION FOR QUESTIONS 2 THROUGH 4
Figures 2a and 2b are the radiographs of a 56-year-old woman who has groin pain and decreased
function 15 months after a total hip replacement using the posterolateral approach. Findings from the
workup for infection are negative and physical examination localizes pain to the hip joint. Records
show the patient underwent total hip surgery with a metal-on-metal bearing.
The patient undergoes cup revision to a more optimal position using a 36-mm metal-polyethylene
bearing. Abductor muscle damage from gross metal debris and inflammation are encountered during
surgery. After cup revision, repair of abductors, and hip brace use for several weeks, the patient has
no more pain.Several months after surgery, the patent returns with a history of multiple hip
dislocations that have proven refractory to treatment including hip precautions, bracing, and exercise.
Radiographs perfectly positioned components; the patient has no pain, and examination under
anesthesia shows show hip instability.
Question 2-Before recommending revision total hip arthroplasty, what other step(s) should be
included in the workup?
1. Aspiration of the hip joint and diagnostic injection of an anesthetic
2. Draw an erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
3. Three-phase bone scan of the hip
4. Lumbar spine radiographs
PREFERRED RESPONSE: 2
Question 3-Before this patient’s most recent revision surgery, her symptoms were most likely
related to
1. systemic metal ion debris.
2. component malposition.
3. leg length inequality.
4. Head-neck taper corrosion.
PREFERRED RESPONSE: 2
Question 4-After revision surgery, this patient’s total hip remains unstable and unresponsive
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,2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
to nonsurgical treatment.What is the most appropriate surgical option?
1. Trochanteric advancement
2. Revision to a constrained polyethylene liner
3. Revision to the largest head size and increase leg length 3
4. Resection with repeat abductor repair, with staged reimplantation
3
, 2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
PREFERRED RESPONSE: 2
DISCUSSION FOR QUESTIONS 2 THROUGH 4
The differential diagnosis of pain after a total hip arthroplasty encompasses a number of etiologies,
but the question is directed to a basic and essential part of the workup (ie, definitively considering and
ruling in or out the possibility of deep sepsis). Radiographs may point to other, obvious sources of
pain, but the orthopaedic surgeon must not overlook the possibility that deep sepsis is the
predominant cause of the symptoms. Accordingly, ESR and CRP are logical next steps in the workup
in this clinical scenario. Radiographs show increased anteversion of the metal socket, and pain
etiologies can include psoas irritation, hip instability, or adverse tissue reaction to metal debris
generated by suboptimal implant position leading to higher bearing contact stresses and/or
impingement. Once other common etiologies of hip pain have been excluded such as deep infection
or lumbar pathology, the most likely cause of hip symptoms should be considered. Here the evidence
points to a malpositioned acetabular component. Systemic ion dissemination may occur in this patient
but will not produce hip pain. Head-neck taper corrosion can generate metallic debris, but a more
likely source of local metallic debris is edge loading or impingement of the metal-metal bearing. Leg
length inequality can be distressing to a patient but will usually not result in hip pain. Component
malposition is the best answer. Among the spectrum of clinical presentations following failed metal-
metal total hip replacements, abductor damage from localized inflammation is one finding that can
lead to hip instability. A reasonable treatment option is to repair the abductors as best as possible,
with augmentation of soft-tissue repair using graft tissue, a large-diameter femoral head, and a
constrained polyethylene liner. This is a challenging clinical scenario because chronic hip instability
with deficient abductors is difficult to control and is an indication for the use of constrained
components. Revision to a larger head and increased leg lengths will not address the underlying
cause of instability. Hip resection is not necessary because this is not a septic total hip.
Question 5-A 67-year-old active man returns for routine follow up 12 years after hip
replacement. He has no hip pain.Radiographs revealed a well-circumscribed osteolytic lesion
around a single acetabular screw. All hip components were perfectly positioned. Six months
later, comparison radiographs show an increase in the size of the osteolytic lesion. A CT scan
shows a well-described lesion that is 3 cm at its largest diameter and is localized around 1
screw hole with an eccentric femoral head. What treatment is appropriate,assuming well-fixed
cementless total hip components exist?
1. Revision of the polyethylene liner, removal of the screw, and debridement of the osteolytic
lesion with or without bone grafting
2. Revision of the acetabular component to a newer design without screws
3. Removal of the screw, revision of the polyethylene liner, and stem cell injection into the lytic
lesion
4. Removal of the offending screw from the metal socket and placement of a new polyethylene
liner in the existing socket
DISCUSSION-With a well-fixed acetabular metal shell and a localized osteolytic lesion, good
outcomes can be expected with liner revision in this clinical scenario with retention of the metal
socket, assuming no damage to the components or other unexpected findings during revision surgery.
Here, complete cup revision is not warranted considering the appropriate implant position. Beaule and
associates reviewed 83 consecutive patients (90 hips) in which a well-fixed acetabular component
was retained in clinical scenarios such as the one described; no hip showed recurrence or expansion
of periacetabular osteolytic lesions. If the metal cup is unstable, or if the osteolytic lesion is not
amenable to debridement through the screw hole,acetabular component revision may be indicated.
PREFERRED RESPONSE: 1
Question 6-A 70-year-old man underwent removal of an infected total hip arthroplasty (THA)
and insertion of an articulating antibiotic-loaded spacer to treat a deep periprosthetic hip
infection. He was in a nursing home receiving intravenous antibiotics 3 weeks after surgery
when he tripped and fell. Examination shows swelling in the mid and distal thigh, intact skin
and neurovascular structures, and severe pain with knee or hip movement. Radiographs of the
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,2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
Question 1-Cementless knee replacements are associated with
1. increased risk for revision.
2. increased wear of the polyethylene insert.
3. increased infection risk.
4. significantly higher Knee Society Scores (KSS).
DISCUSSION-Many published series comparing cementless to cemented knee replacements show
no difference in KSS or infection risk, but data in several registries demonstrate a significant increase
in the revision rates for cementless knees. Although no difference in poly wear occurred, loosening of
the tibial component was the most common cause of failure. PREFERRED RESPONSE: 1
CLINICAL SITUATION FOR QUESTIONS 2 THROUGH 4
Figures 2a and 2b are the radiographs of a 56-year-old woman who has groin pain and decreased
function 15 months after a total hip replacement using the posterolateral approach. Findings from the
workup for infection are negative and physical examination localizes pain to the hip joint. Records
show the patient underwent total hip surgery with a metal-on-metal bearing.
The patient undergoes cup revision to a more optimal position using a 36-mm metal-polyethylene
bearing. Abductor muscle damage from gross metal debris and inflammation are encountered during
surgery. After cup revision, repair of abductors, and hip brace use for several weeks, the patient has
no more pain.Several months after surgery, the patent returns with a history of multiple hip
dislocations that have proven refractory to treatment including hip precautions, bracing, and exercise.
Radiographs perfectly positioned components; the patient has no pain, and examination under
anesthesia shows show hip instability.
Question 2-Before recommending revision total hip arthroplasty, what other step(s) should be
included in the workup?
1. Aspiration of the hip joint and diagnostic injection of an anesthetic
2. Draw an erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
3. Three-phase bone scan of the hip
4. Lumbar spine radiographs
PREFERRED RESPONSE: 2
Question 3-Before this patient’s most recent revision surgery, her symptoms were most likely
related to
1. systemic metal ion debris.
2. component malposition.
3. leg length inequality.
4. Head-neck taper corrosion.
PREFERRED RESPONSE: 2
Question 4-After revision surgery, this patient’s total hip remains unstable and unresponsive
2
,2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
to nonsurgical treatment.What is the most appropriate surgical option?
1. Trochanteric advancement
2. Revision to a constrained polyethylene liner
3. Revision to the largest head size and increase leg length 3
4. Resection with repeat abductor repair, with staged reimplantation
3
, 2013 Adult Reconstructive Surgery of the Hip and Knee Self-Assessment Examination by Dr.Dhahirortho
PREFERRED RESPONSE: 2
DISCUSSION FOR QUESTIONS 2 THROUGH 4
The differential diagnosis of pain after a total hip arthroplasty encompasses a number of etiologies,
but the question is directed to a basic and essential part of the workup (ie, definitively considering and
ruling in or out the possibility of deep sepsis). Radiographs may point to other, obvious sources of
pain, but the orthopaedic surgeon must not overlook the possibility that deep sepsis is the
predominant cause of the symptoms. Accordingly, ESR and CRP are logical next steps in the workup
in this clinical scenario. Radiographs show increased anteversion of the metal socket, and pain
etiologies can include psoas irritation, hip instability, or adverse tissue reaction to metal debris
generated by suboptimal implant position leading to higher bearing contact stresses and/or
impingement. Once other common etiologies of hip pain have been excluded such as deep infection
or lumbar pathology, the most likely cause of hip symptoms should be considered. Here the evidence
points to a malpositioned acetabular component. Systemic ion dissemination may occur in this patient
but will not produce hip pain. Head-neck taper corrosion can generate metallic debris, but a more
likely source of local metallic debris is edge loading or impingement of the metal-metal bearing. Leg
length inequality can be distressing to a patient but will usually not result in hip pain. Component
malposition is the best answer. Among the spectrum of clinical presentations following failed metal-
metal total hip replacements, abductor damage from localized inflammation is one finding that can
lead to hip instability. A reasonable treatment option is to repair the abductors as best as possible,
with augmentation of soft-tissue repair using graft tissue, a large-diameter femoral head, and a
constrained polyethylene liner. This is a challenging clinical scenario because chronic hip instability
with deficient abductors is difficult to control and is an indication for the use of constrained
components. Revision to a larger head and increased leg lengths will not address the underlying
cause of instability. Hip resection is not necessary because this is not a septic total hip.
Question 5-A 67-year-old active man returns for routine follow up 12 years after hip
replacement. He has no hip pain.Radiographs revealed a well-circumscribed osteolytic lesion
around a single acetabular screw. All hip components were perfectly positioned. Six months
later, comparison radiographs show an increase in the size of the osteolytic lesion. A CT scan
shows a well-described lesion that is 3 cm at its largest diameter and is localized around 1
screw hole with an eccentric femoral head. What treatment is appropriate,assuming well-fixed
cementless total hip components exist?
1. Revision of the polyethylene liner, removal of the screw, and debridement of the osteolytic
lesion with or without bone grafting
2. Revision of the acetabular component to a newer design without screws
3. Removal of the screw, revision of the polyethylene liner, and stem cell injection into the lytic
lesion
4. Removal of the offending screw from the metal socket and placement of a new polyethylene
liner in the existing socket
DISCUSSION-With a well-fixed acetabular metal shell and a localized osteolytic lesion, good
outcomes can be expected with liner revision in this clinical scenario with retention of the metal
socket, assuming no damage to the components or other unexpected findings during revision surgery.
Here, complete cup revision is not warranted considering the appropriate implant position. Beaule and
associates reviewed 83 consecutive patients (90 hips) in which a well-fixed acetabular component
was retained in clinical scenarios such as the one described; no hip showed recurrence or expansion
of periacetabular osteolytic lesions. If the metal cup is unstable, or if the osteolytic lesion is not
amenable to debridement through the screw hole,acetabular component revision may be indicated.
PREFERRED RESPONSE: 1
Question 6-A 70-year-old man underwent removal of an infected total hip arthroplasty (THA)
and insertion of an articulating antibiotic-loaded spacer to treat a deep periprosthetic hip
infection. He was in a nursing home receiving intravenous antibiotics 3 weeks after surgery
when he tripped and fell. Examination shows swelling in the mid and distal thigh, intact skin
and neurovascular structures, and severe pain with knee or hip movement. Radiographs of the
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