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 4901
Topic: 3. Adult Reconstruction (Hip & Knee)
Cementless knee replacements are associated with
Correct Answer & Explanation
. increased risk for revision.
Explanation
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.
Question 4902
Topic: Total Hip Arthroplasty (THA)
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.
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Before recommending revision total hip arthroplasty, what other step(s) should be included in the workup?
Correct Answer & Explanation
. Draw an erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
Explanation
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 metalmetal 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 4903
Topic: Total Hip Arthroplasty (THA)
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.
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Before this patient’s most recent revision surgery, her symptoms were most likely related to
Correct Answer & Explanation
. component malposition.
Explanation
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 metalmetal 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 4904
Topic: Total Hip Arthroplasty (THA)
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.
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After revision surgery, this patient’s total hip remains unstable and unresponsive to nonsurgical treatment.What is the most appropriate surgical option?
Correct Answer & Explanation
. Revision to a constrained polyethylene liner
Explanation
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 metalmetal 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 4905
Topic: 3. Adult Reconstruction (Hip & Knee)
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?
Correct Answer & Explanation
. Revision of the polyethylene liner, removal of the screw, and debridement of the osteolytic lesion with or without bone grafting
Explanation
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.
Question 4906
Topic: Total Hip Arthroplasty (THA)
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 femur show a fracture below the implant. What is the most appropriate treatment for the fracture?
Correct Answer & Explanation
. Open reduction and internal fixation of the fracture with a lateral plate and screws
Explanation
This patient has a type C periprosthetic femoral fracture. The articulating spacer is not involved in the fracture, which is well distal to the implant. The most appropriate treatment is open reduction and internal fixation of the fracture. Traction is not appropriate for this fracture because it can be treated surgically despite the history of previous hip infection. Traction would also be needed for at least 5 weeks to delay surgical treatment of the periprosthetic fracture until the time of second-stage revision THA. The fracture is fairly distal and revision to a longer antibiotic-loaded implant or uncemented stem is not suitable for this fracture pattern because it extends well past the isthmus. A femoral stem in the distal fragment would provide little stability for the fracture. Additionally, removing the articulating spacer and reimplantation using a long-stem fluted uncemented hip replacement is not appropriate because it would be premature to reimplant this man’s hip while he is still receiving treatment for his deep-hip infection.
Question 4907
Topic: 3. Adult Reconstruction (Hip & Knee)
A 68-year-old woman had advanced right knee arthritis and total knee replacement was planned. She learned she had primary biliary cirrhosis at age 41 and now has advancing liver failure. Preoperative coagulation tests show a baseline International Normalized Ratio (INR) of 1.36. Appropriate methods to prevent thromboembolic disease as recommended by the 2011 AAOS Clinical Practice Guideline,Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty,include
Correct Answer & Explanation
. use of mechanical prophylaxis (eg, pneumatic calf compressors) while in the hospital.
Explanation
The 2011 AAOS Clinical Practice Guideline, Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty, recommends the use of mechanical prophylaxis for patients at increased risk for bleeding (including those with liver disease or hemophilia). This recommendation is the consensus of the workgroup that established these guidelines because there was insufficient evidence to justify a stronger recommendation in this clinical scenario. The other responses use no prophylaxis or pharmacological prophylaxis. Pharmacological prophylaxis is not recommended in patients who are at increased risk for bleeding.---
Question 4908
Topic: 3. Adult Reconstruction (Hip & Knee)
A 78-year-old active woman who weighs 227 pounds has a long history of type 2 diabetes mellitus and had a total knee replacement 15 years ago. She underwent revision arthroplasty for loose components. After surgery, she fell and now has a 35-degree extensor lag with a high-riding patella on the lateral radiographic view. When attempting to surgically repair the torn extensor, gross purulence is found, leading to a resection with an antibiotic cement spacer. Enterococcus bacteria are recovered on cultures a few days later; this species is resistant to several antibiotics. The wound drains for 3 weeks and then heals with continued redness, pain, and swelling despite intravenous antibiotics. What is the most effective long-term treatment for this patient?
Correct Answer & Explanation
. Knee fusion
Explanation
Arthrodesis may be the most satisfactory long-term option for this elderly, obese patient even though all knee motion will be lost. The other options presented are associated with unpredictable results and higher failure rates.
Question 4909
Topic: 3. Adult Reconstruction (Hip & Knee)
A 65-year-old woman with type 2 diabetes mellitus and hypertension who underwent an index total knee arthroplasty (TKA) 1 year ago has a knee aspirate culture positive methicillin-resistant Staphylococcus aureus periprosthetic joint infection after 2 days of increasing pain and swelling. She states her knee“never felt right.” Her erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels are elevated. Radiographs reveal well-fixed, appropriately positioned components.
What is the most appropriate treatment?
Correct Answer & Explanation
. Open debridement, poly exchange, and intravenous (IV) antibiotics
Explanation
This patient has had a painful knee joint since surgery, and it is possible this is a chronic infection. In this setting, a 2-stage reimplantation procedure is most appropriate. There is no role for arthroscopic debridement and resection arthroplasty is not indicated. During the second stage, it is important to obtain cultures to confirm successful eradication of the infection. If there is clinical suspicion for persistent joint infection, an intraoperative frozen section can be indicated, but gram stain is useful. Aspiration and culture prior to the intraoperative culture should be obtained after the patient has not been taking the antibiotic for a minimum of 2 weeks. ESR and CRP trends are more valuable than the actual numbers in this setting. Finally, leukocyte-labeled imaging has no role in this setting.
Question 4910
Topic: 3. Adult Reconstruction (Hip & Knee)
A 65-year-old woman with type 2 diabetes mellitus and hypertension who underwent an index total knee arthroplasty (TKA) 1 year ago has a knee aspirate culture positive methicillin-resistant Staphylococcus aureus periprosthetic joint infection after 2 days of increasing pain and swelling. She states her knee“never felt right.” Her erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels are elevated. Radiographs reveal well-fixed, appropriately positioned components.
The patient undergoes a successful first stage that includes removal of implants and placement of an articulating spacer. IV antibiotics are administered for 6 weeks. Appropriate clinical management for this patient includes
Correct Answer & Explanation
. leukocyte-labeled imaging.
Explanation
This patient has had a painful knee joint since surgery, and it is possible this is a chronic infection. In this setting, a 2-stage reimplantation procedure is most appropriate. There is no role for arthroscopic debridement and resection arthroplasty is not indicated. During the second stage, it is important to obtain cultures to confirm successful eradication of the infection. If there is clinical suspicion for persistent joint infection, an intraoperative frozen section can be indicated, but gram stain is useful. Aspiration and culture prior to the intraoperative culture should be obtained after the patient has not been taking the antibiotic for a minimum of 2 weeks. ESR and CRP trends are more valuable than the actual numbers in this setting. Finally, leukocyte-labeled imaging has no role in this setting.
Question 4911
Topic: Total Knee Arthroplasty (TKA)
A 77-year-old man who had right total knee replacement surgery 2½ years ago has had knee pain since surgery. The pain is diffuse, constant, and made worse with activity. He notes warmth and swelling in his knee. Examination shows a well-healed incision, no erythema, moderate warmth, synovitis, and an effusion. The knee is stable, and has an arc of flexion between 3 and 120 degrees. Radiographs show well-fixed and well-aligned implants. What is the most appropriate initial treatment?
Correct Answer & Explanation
. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) labs
Explanation
This patient’s history and physical findings are concerning for deep infection. Inflammatory markers (ESR and CRP) should first be obtained, and, if levels are elevated, proceed to knee aspiration for synovial cell count and culture. A bone scan is not indicated in an initial investigation for deep infection, rarely is helpful, and is not cost effective. A CT scan to assess implant rotation is an appropriate investigation for knee pain when the clinical scenario is not suspicious for a deep infection and when infection has been excluded.
Question 4912
Topic: 3. Adult Reconstruction (Hip & Knee)
Figures 15a and 15b are the 6-week postsurgical anteroposterior hip radiograph and current radiograph of a 54-year-old avid hiker who returns for routine follow-up 3 years after an uncomplicated uncemented modular metal-on-metal hip replacement. He reports mild activity-related aching diffusely around the right hip region, but does not feel restricted with his activities. Examination reveals no local tenderness, a well-healed incision, and mild discomfort at the extremes of rotation. An erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are obtained, showing 9 mm/h (reference range, 0-20 mm/h) and 2.0 mg/L (reference range, 0.08-3.1 mg/L), respectively. What is the etiology of the radiographic finding?
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Correct Answer & Explanation
. Osteolysis secondary to metal particle wear (an adverse reaction to metal debris)
Explanation
The radiograph shows a large area of osteolysis involving the proximal femur. The implants appear solidly fixed on radiographs and, in the absence of symptoms, it is unlikely the implants are loose or infected. Although infection or metastatic disease is a possibility, the normal ESR and CRP values make the diagnosis of deep infection unlikely. The most likely cause for the radiographic findings is wear from metal particles resulting in an adverse local tissue response and osteolysis.
Question 4913
Topic: 3. Adult Reconstruction (Hip & Knee)
What risk factor is associated with a poor prognosis after revision of a failed metal-on-metal resurfacing hip arthroplasty to total hip arthroplasty?
Correct Answer & Explanation
. Femoral neck fracture
Explanation
Recent clinical series have focused on the high complication rates and problems resulting from revision cases with pseudotumor formation. Pseudotumors are probably related to very high levels of cobalt and chrome particulate wear debris. The underlying etiology most likely is edge wear or impingement that destroys the congruity of the articulation. Revision surgery was quite difficult in one series, particularly if there were large amounts of soft-tissue destruction or nerve involvement. There was a high re-revision rate, often resulting from recurrent pseudotumors with large amounts of debris that could not be removed with the initial revision. The other causes of revision that can cause failure of the femoral resurfacing component can be easily revised with a femoral stem component, and results can be nearly as favorable as with a primary hip replacement.
Question 4914
Topic: 3. Adult Reconstruction (Hip & Knee)
Ten-year follow-up studies of total hip replacements performed with modern alumina ceramic femoral heads and acetabular liners show what outcomes?
Correct Answer & Explanation
. Low incidence of osteolysis, squeaking noise, and ceramic head fractures
Explanation
Ten-year follow-up data have been published from a number of clinical centers worldwide that describe the outcomes of total hip arthroplasties performed with third-generation alumina ceramic bearings (metal-polyethylene control hips often were included in the same series). These studies show no osteolysis around well-fixed metal components, and a small incidence of revision surgery to address bearing noise (squeaking) or ceramic femoral head fracture. Newer ceramic materials are associated with satisfactory outcomes in terms of elimination of wear-mediated osteolysis, but problems such as bearing noise and catastrophic femoral head failure have not been eliminated even though the risk for these complications is small and much improved compared to risk associated with earlier generations of ceramic bearings.
Question 4915
Topic: 3. Adult Reconstruction (Hip & Knee)
When do most symptomatic thromboembolic events occur after undergoing total joint arthroplasty?
Correct Answer & Explanation
. Between 1 week and 6 weeks after surgery
Explanation
Most clinical venous thromboembolism events occur between the second and sixth weeks after surgery. It is estimated that 10% of patients are readmitted to the hospital within the first 3 months after total hip or knee arthroplasties. Most pulmonary events on the day of surgery are related to fat embolism or cardiac events.
Question 4916
Topic: 3. Adult Reconstruction (Hip & Knee)
What effect does morbid obesity (body mass index [BMI] higher than 40) have on total knee arthroplasty outcomes?
Correct Answer & Explanation
. No difference in functional outcome
Explanation
Patients with a BMI higher than 40 are more likely than nonobese patients to have radiolucent lines on postoperative radiographs. These patients have a higher rate of complications, inferior survivorship with a higher rate of revision, and poorer function scores.
Question 4917
Topic: Total Knee Arthroplasty (TKA)
A 70-year-old woman who underwent total knee replacement 18 months ago has had 3 weeks of moderate drainage from a previously healed wound. What is the most appropriate treatment?
Correct Answer & Explanation
. Two-stage debridement and reconstruction
Explanation
This situation represents a definitively and chronically infected knee replacement. Antibiotic therapy alone may suppress the infection but will not eradicate it. Debridement and polyethylene exchange would be appropriate treatment for an early postoperative infection. The treatment of choice is to perform a 2-stage debridement and reconstruction. Although not among the listed choices, an aspiration or culture can be done presurgically and may help clinicians identify the best antibiotics to treat the condition. Antibiotic selection would not affect the need for the 2-stage reconstruction, however.
Question 4918
Topic: 3. Adult Reconstruction (Hip & Knee)
A 66-year-old woman had fever, chills, and increasing pain in her right hip. She underwent a total hip arthroplasty using large-head metal-on-metal articulation 4 years earlier without complications. Her hip pain began about 1 month ago following several days of productive cough that her primary care physician had diagnosed as a viral illness. She had elevated serology with an erythrocyte sedimentation rate of 70 mm/h (reference range, 0-20 mm/h) and C-reactive protein of 3.5 mg/L (reference range, 0.08-3.1 mg/L). There is no radiographic evidence of loosening or adverse bone remodeling around the hip arthroplasty. What is the most appropriate course of action?
Correct Answer & Explanation
. Hip aspiration
Explanation
This patient has a history and laboratory values highly suggestive of infection following her upper-respiratory-tract infection. Hip aspiration is the most appropriate work-up in this acute setting. Metal ion level assessment is not useful in the workup for acute infection. A MARS MRI scan would be less effective in diagnosing infection than hip aspiration. Empirical use of antibiotics is not appropriate.
Question 4919
Topic: 3. Adult Reconstruction (Hip & Knee)
A 57-year-old woman reported pain 1 year after total knee arthroplasty (TKA). The pain was characterized as a sharp catching anterior pain that was aggravated by rising from a chair or climbing stairs. Physical examination revealed a mild effusion and a range of motion of 2 to 130 degrees with patellar crepitus. Symptoms were reproduced by resisted knee extension. Radiographs showed a wellaligned posterior-stabilized TKA without evidence of component loosening.
What is the most likely cause of this patient’s pain?
Correct Answer & Explanation
. Patella clunk syndrome
Explanation
Patella clunk syndrome is caused by the development of a fibrous nodule on the posterior aspect of the quadriceps tendon at its insertion into the patella. It causes a painful catching sensation when the extensor mechanism traverses over the trochlear notch as the knee extends from 45 degrees of flexion to 30 degrees from full extension. It characteristically occurs in posterior stabilized total knees and appears to be related to femoral component design. The syndrome can usually be prevented by excising the residual synovial fold just proximal to the patella. Flexion gap instability can also be acause of a painful total knee arthroplasty, but is less common in posterior stabilized implants. Femoral component malrotation can be a cause of pain attributable to flexion gap imbalance or patella tracking problems. Polyethylene wear would be unlikely after just 1 year. Patella clunk syndrome can usually be successfully addressed with arthroscopic synovectomy and recurrence is uncommon. Physical therapy may help to strengthen the quadriceps following synovectomy, but will not resolve the clunk syndrome symptoms. Femoral or tibial insert revision is not indicated if patella clunk syndrome is the only problem resulting in a painful total knee arthroplasty.
Question 4920
Topic: 3. Adult Reconstruction (Hip & Knee)
A 57-year-old woman reported pain 1 year after total knee arthroplasty (TKA). The pain was characterized as a sharp catching anterior pain that was aggravated by rising from a chair or climbing stairs. Physical examination revealed a mild effusion and a range of motion of 2 to 130 degrees with patellar crepitus. Symptoms were reproduced by resisted knee extension. Radiographs showed a wellaligned posterior-stabilized TKA without evidence of component loosening.
What is the recommended treatment for this patient?
Correct Answer & Explanation
. Physical therapy
Explanation
Patella clunk syndrome is caused by the development of a fibrous nodule on the posterior aspect of the quadriceps tendon at its insertion into the patella. It causes a painful catching sensation when the extensor mechanism traverses over the trochlear notch as the knee extends from 45 degrees of flexion to 30 degrees from full extension. It characteristically occurs in posterior stabilized total knees and appears to be related to femoral component design. The syndrome can usually be prevented by excising the residual synovial fold just proximal to the patella. Flexion gap instability can also be acause of a painful total knee arthroplasty, but is less common in posterior stabilized implants. Femoral component malrotation can be a cause of pain attributable to flexion gap imbalance or patella tracking problems. Polyethylene wear would be unlikely after just 1 year. Patella clunk syndrome can usually be successfully addressed with arthroscopic synovectomy and recurrence is uncommon. Physical therapy may help to strengthen the quadriceps following synovectomy, but will not resolve the clunk syndrome symptoms. Femoral or tibial insert revision is not indicated if patella clunk syndrome is the only problem resulting in a painful total knee arthroplasty.
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