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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 60 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 1181

Topic: Total Knee Arthroplasty (TKA)
A 70-year-old woman has a 3-year history of gradually increasing diffuse and global right knee pain. Her main issues are difficulty with stairs, stiffness with prolonged sitting, and swelling. She has taken NSAIDs and has received intra-articular steroid injections, all with decreasing efficacy. Her right knee examination reveals a range of motion of 15° to 80° with a fixed deformity to varus and valgus stress. Her symptoms are no longer manageable nonsurgically. Radiographs reveal a 30-degree mechanical axis deformity. The deformity shown in the figure is predominantly associated with
. a hypoplastic lateral femoral condyle.
. a contracted medial collateral ligament.
. an excessive proximal tibial slope.
. trochlear dysplasia.

Correct Answer & Explanation

. a hypoplastic lateral femoral condyle.

Explanation

DISCUSSION: In the setting of valgus deformities, TKA poses different challenges than those encountered when varus deformities are present. Most valgus alignment is attributable to a deformity of the distal femur rather than of the proximal tibia, as seen in varus knees. One of the major anatomical differences is a hypoplastic lateral femoral condyle which, when not recognized and used as a rotational reference point, can lead to internal rotation of the femoral component. This malrotation in turn leads to patellofemoral maltracking or instability, which is a common complication associated with primary TKA.

Question 1182

Topic: 3. Adult Reconstruction (Hip & Knee)
During total hip arthroplasty, profuse bleeding is noted following predrilling for placement of an acetabular component screw. The drill most likely penetrated too deep in the
. anterior-superior acetabular quadrant.
. posterior-superior acetabular quadrant.
. posterior-inferior acetabular quadrant.
. medial acetabular wall.
. ischial body.

Correct Answer & Explanation

. anterior-superior acetabular quadrant.

Explanation

DISCUSSION: The acetabular quadrants are defined by two lines: one drawn from the anterosuperior iliac spine to the posterior fovea, forming acetabular halves, and a second drawn perpendicular to the first at the midpoint of the acetabulum, forming four quadrants. The anterior quadrants should be avoided because improper screw placement may injure the external iliac artery and vein, as well as the obturator nerve, artery, and vein. These structures lie close to the pelvic bone, with little protective interposition of soft tissue. REFERENCES: Wasielewski RC, Cooperstein LA, Kruger MP, et al: Acetabular anatomy and the transacetabular fixation of screws in total hip arthroplasty. J Bone Joint Surg Am 1990;72:501-508.

Question 1183

Topic: Total Knee Arthroplasty (TKA)
A man who underwent right total knee replacement surgery 2.5 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°. Radiographs show well-fixed and well-aligned implants. What is the most appropriate initial treatment?
. Knee aspiration for culture
. CT of the knee to assess implant rotation
. Indium-111 leukocyte/technetium-99m sulfur colloid scan of the knee
. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) laboratory studies

Correct Answer & Explanation

. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) laboratory studies

Explanation

This patient's history and physical findings are concerning for deep infection. Inflammatory markers, including ESR and CRP, should be obtained first. If the levels are elevated, knee aspiration should be performed for the synovial cell count and culture. A bone scan is not indicated in an initial investigation for deep infection; it is rarely helpful and is not cost-effective. CT 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 1184

Topic: Total Knee Arthroplasty (TKA)

A 17-year-old basketball player and pole vaulter who has had anterior knee pain for the past 18 months now reports a recent inability to jump. Based on the MRI scan shown in Figure 11, management should consist of Review Topic

. debridement and repair.
. cast immobilization.
. aggressive overload eccentric strengthening.
. ice massage and continued athletic participation.
. steroid injection.

Correct Answer & Explanation

. debridement and repair.

Explanation

The MRI scan reveals a partial patellar tendon rupture in conjunction with chronic patellar tendinitis. Mild and moderate patellar tendinitis may be treated nonsurgically with rest, stretching, strengthening, and anti-inflammatory drugs. Severe tendinopathy or extensor mechanism disruption is best treated surgically with tendon debridement and repair.

Question 1185

Topic: 3. Adult Reconstruction (Hip & Knee)
The anterior approach to total hip arthroplasty requires dissection between which of the following muscle planes?
. Sartorius and gluteus maximus
. Gluteus minimus and rectus femoris
. Rectus femoris and sartorius
. Tensor fascia lata and sartorius
. Tensor fascia lata and rectus femoris

Correct Answer & Explanation

. Tensor fascia lata and sartorius

Explanation

The anterior approach to the hip joint involves identifying the plane between the tensor fascia lata and the sartorius muscles.

Question 1186

Topic: Total Hip Arthroplasty (THA)
A 63-year-old woman had a primary total hip arthroplasty 7 years ago that included a proximally coated titanium stem, a cobalt alloy femoral head, a titanium hemispherical acetabular component, and a polyethylene liner. She did well for 4 years but has now had two dislocations and reports pain and weakness around the left hip. She denies any fevers, chills, or constitutional symptoms. On examination, the patient walks well without any signs of an antalgic or Trendelenburg gait. Her abductor mechanism demonstrates good strength. Her erythrocyte sedimentation rate and C-reactive protein level are normal. On radiographs, all components appear well fixed and in good alignment. What is the most appropriate treatment at this time?
. Physical therapy to improve hip stability
. Use of an abduction brace to limit the patient’s range of motion
. Conversion to a constrained acetabular liner
. Cobalt and chromium serum metal ion level testing

Correct Answer & Explanation

. Cobalt and chromium serum metal ion level testing

Explanation

Trunnionosis is a recently recognized complication following total hip arthroplasty and can occur when a cobalt alloy femoral head is used on a titanium alloy or cobalt alloy femoral stem. Patients often present with pain or swelling around the hip but at times can present with instability. In a patient with a cobalt alloy femoral head who presents with instability, swelling, and weakness around the hip, the potential for trunnionosis and an adverse local tissue reaction should be considered.

Question 1187

Topic: 3. Adult Reconstruction (Hip & Knee)
When performing a total knee arthroplasty using modular components, what is the minimum recommended thickness of an ultra-high molecular weight polyethylene insert for a tibial component?
. 3 to 5 mm
. 6 to 8 mm
. 10 to 12 mm
. 13 to 15 mm
. Greater than 15 mm

Correct Answer & Explanation

. 6 to 8 mm

Explanation

Polyethylene wear has been identified as a major contributor to failure of total knee implants, of which thickness is an important factor. Several studies have shown that the minimum thickness should be 6 to 8 mm. While Wright and Bartel have shown that 6 to 8 mm has been recommended as the minimum thickness of an ultra-high molecular weight polyethylene insert for a tibial component in total knee arthroplasty, more recent work by Meding and associates and Worland and associates has verified the clinical efficacy of 4 mm of polyethylene in compression-molded anatomic graduated nonmodular components.

Question 1188

Topic: 3. Adult Reconstruction (Hip & Knee)

03 Early failure of a unicompartmental knee arthroplasty that is the result of polyethylene wear is primarily caused by

. malalignment
. instability
. metal backing of the tibial component
. gamma irradiation sterilization and shelf storage in air 5- obesity.back answer Question 62.03

Correct Answer & Explanation

. malalignment

Explanation

When components are sterilized with gamma irradiation, there is the formation of a large number of free radicals, making the polyethylene prone to oxidation and decreasing the mechanical toughness. The cited article by Engh and colleagues reported on early failure of unicompartmental knees with an all poly tibial component that had been sterilized with gamma irradiation and had a prolonged shelf life, (>4 years). All the components that were revised showed visible wear, and some were fragmented with full thickness fractures of the polyethylene. They sent the first 4 retrievals for studies of oxidation and all were found to be highly oxidized.back to this question next question

Question 1189

Topic: 3. Adult Reconstruction (Hip & Knee)
What is the most important preoperative factor predicting conversion to total hip arthroplasty after arthroscopic surgery of the hip?
. Age over 60 years
. Morbid obesity
. Diagnosis of osteoarthritis
. Tobacco use

Correct Answer & Explanation

. Morbid obesity

Explanation

DISCUSSION: The authors cited in the references examined large databases to determine the risk factors for conversion to total hip arthroplasty after arthroscopic surgery of the hip. In the study by Kester and associates, obesity had an odds ratio (OR) of 5.6 for conversion to hip arthroplasty, whereas age over 60 years had an OR of 3.4, osteoarthritis had an OR of 2.4, and tobacco use had an OR of 1.9.

Question 1190

Topic: Total Hip Arthroplasty (THA)
A 70-year-old man undergoes removal of an infected total hip arthroplasty (THA) and insertion of an articulating antibiotic-loaded spacer to treat a deep periprosthetic hip infection. While in a nursing home receiving intravenous antibiotics 3 weeks after surgery, the patient trips and falls. Examination reveals swelling in the mid and distal thigh, intact skin and neurovascular structures, and severe pain with knee or hip movement. Radiographs of the femur are shown in Figures 1 through 4. What is the most appropriate treatment for the fracture below the implant?
. Balanced traction to address concern for persistent infection with reoperation
. Open reduction and internal fixation of the fracture with a lateral plate and screws
. Removal of the articulating spacer and revision to a longer-stem antibiotic-loaded articulating spacer
. Removal of the articulating spacer and reimplantation using a long-stem fluted uncemented hip replacement

Correct Answer & Explanation

. Open reduction and internal fixation of the fracture with a lateral plate and screws

Explanation

DISCUSSION: 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 the injury can be treated surgically despite the history of previous hip infection. Traction would also be needed for at least 5 weeks and would delay the 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. Removal of the articulating spacer and reimplantation using a long-stem fluted uncemented hip replacement is not appropriate, because it would be premature to reimplant the man's hip while he is still receiving treatment for a deep hip infection.

Question 1191

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 131 is the abdominal radiograph of a 70-year-old man who experiences nausea and abdominal tightness 48 hours after undergoing left total knee arthroplasty. An examination reveals severe abdominal distension and markedly decreased bowel sounds. Insertion of a nasogastric tube does not relieve abdominal tightness. What is the best next step?

. Endoscopy
. Gastrostomy
. Colonoscopy
. Laparotomy

Correct Answer & Explanation

. Endoscopy

Explanation

DISCUSSIONThe abdominal radiograph reveals an acute colonic pseudo-obstruction. It is associated with parenteral narcotic use and hypokalemia. Initial treatment is insertion of a nasograstric tube, discontinuation of parenteral narcotics, and correction of electrolyte imbalances. If a pseudo-obstruction is not relieved, colonoscopy should be performed.

Question 1192

Topic: 3. Adult Reconstruction (Hip & Knee)
Polyethylene wear of the bearing surface has been recognized as a mode of failure in total knee arthroplasty; therefore, many patients are offered polyethylene exchange. In terms of success rates, this surgical procedure has been reported to have a
. rate of less than 50%, primarily the result of infection.
. rate of greater than 50%.
. lower rate in patients in which metallosis was identified.
. similar rate with or without preoperative osteolysis.
. similar rate regardless of the degree of wear.

Correct Answer & Explanation

. rate of greater than 50%.

Explanation

DISCUSSION: Engh and associates reported on the results of 63 knees (56 patients) following polyethylene exchange. The mean interval between exchange and the index total knee arthroplasty was 59 months. The mean follow-up after exchange was 7.4 years. Seven of 48 knees with adequate follow-up failed. Greater failure occurred if there was more severe wear before the exchange. Greater undersurface wear also resulted in a higher failure rate. Perioperative osteolysis or intraoperative observation of metallosis did not have an impact on the failure of polyethylene exchange. The risk of infection is no different from other total knee arthroplasty revisions. REFERENCES: Wasielewski RC, Parks N, Williams I, et al: Tibial insert undersurface as a contributing source of polyethylene wear debris. Clin Orthop 1997;345:53-59. Engh GA, Koralewicz LM, Pereles TR: Clinical results of modular polyethylene insert exchange with retention of total knee arthroplasty components. J Bone Joint Surg Am 2000;82:516-523.

Question 1193

Topic: 3. Adult Reconstruction (Hip & Knee)
A homebound 75-year-old woman with diabetes mellitus has had progressive left knee pain and swelling for the past 6 weeks. She is febrile with a temperature of 103 degrees F (39.5 degrees C). History reveals that she underwent arthroplasty 5 years ago. Examination shows passive range of motion of 0 to 100 degrees with no active extension. Knee aspiration reveals purulent fluid with a Gram stain showing gram-negative rods. A radiograph is shown in Figure 27. In addition to IV antibiotics, which of the following management options offers the best chance of a successful outcome?
. Incision and drainage with repair of the extensor mechanism
. Removal of components and delayed revision knee arthroplasty with an allograft extensor mechanism
. Removal of components and immediate exchange revision total knee arthroplasty
. Removal of components and delayed knee arthrodesis
. Removal of components and delayed revision knee arthroplasty with extensor mechanism repair

Correct Answer & Explanation

. Removal of components and delayed knee arthrodesis

Explanation

DISCUSSION: The patient has an infected total knee arthroplasty and an interrupted extensor mechanism. A late infection of a total knee arthroplasty in a patient with diabetes mellitus and a virulent organism requires removal of the components, debridement, antibiotic spacers, and surveillance to ensure eradication of the infection. Reconstruction of an incompetent extensor mechanism in an infected knee is extremely unlikely to be successful. Arthrodesis is the procedure of choice if a revision total knee arthroplasty is not likely to succeed. Resection arthroplasty is recommended only as a long-term solution if the patient is medically unable to undergo further surgery. REFERENCES: Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgery, 2002, pp 513-536. Hanssen AD, Rand JA: Evaluation and treatment of infection at the site of a total hip or knee arthroplasty. Instr Course Lect 1999;48:111-122.

Question 1194

Topic: 3. Adult Reconstruction (Hip & Knee)

A surgeon performs a minimally invasive total knee arthroplasty through a quadriceps-sparing approach using medial-to-lateral cutting jigs. When beginning therapy that afternoon, the patient can passively but not actively extend her knee, although she has minimal knee pain. All regional blocks have been discontinued. What is the most likely reason for this finding?

. Quadriceps inhibition
. Avulsion of the quadriceps tendon
. Laceration of the patella tendon
. Femoral nerve palsy

Correct Answer & Explanation

. Laceration of the patella tendon

Explanation

DISCUSSIONThis patient lacks active knee extension. It is not attributable to the regional block because that block is no longer acting. The most likely cause is laceration of the patella tendon, which has been described during both large-incision surgery and minimally invasive surgery. However, this is reported with increased frequency during minimally invasive surgery. Quadriceps inhibition, avulsion of the quadriceps tendon, and femoral nerve palsy can cause lack of active extension, but these problems are less likely because the patient has minimal pain.

Question 1195

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old man has had “catching” in front of his knee since he had a total knee arthroplasty 9 months ago. Examination reveals a palpable and audible snap in the anterior aspect of the knee at about 40 degrees of flexion as the knee is being actively extended. A radiograph of the prosthetic knee will most likely show

. Patella alta
. A metal-backed patella
. Varus malalignment of the knee
. A posterior cruciate-substituting femoral component
. Lateral subluxation of the patella on a Merchant’s view

Correct Answer & Explanation

. A metal-backed patella

Explanation

The patellar “clunk” syndrome is an infrequent complication of TKA. It is diagnosed clinically by a clunking or clicking sensation or sound as the flexed knee is extended usually at about 30-40 degrees of flexion.Pathologically, the clunk is produced by a suprapatellar fibrous nodule seen superior to the patellar component at re-operation. This nodule has been seen to catch in the intercondylar notch in primarily first generation TKAs. Current component designs have decreased this phenomenon through better engineering of femoral components. Treatment is by arthroscopic debridement or open arthroplasty resection. The nodule may be recurrent.

Question 1196

Topic: 3. Adult Reconstruction (Hip & Knee)
A 52-year-old woman has a 60-degree extensor lag following a right total knee arthroplasty performed 16 months ago. Since the time of her primary total knee arthroplasty, she has undergone primary repair of a patellar tendon rupture that occurred after a fall 8 months ago. A lateral radiograph of the knee is shown in Figure 52. A CT scan obtained to determine component rotation showed that the femoral component is internally rotated 9 degrees and the tibial component is internally rotated 12 degrees. Appropriate management at this time should include:
. A structured physical therapy program to increase quadriceps muscle strength.
. A hinged knee brace locked in extension while ambulating.
. Exchange of the modular polyethylene spacer to a thicker insert and reconstruction of the patellar tendon using hamstring augmentation.
. Exchange of the modular polyethylene spacer to a thicker insert and reconstruction of the patellar tendon using an extensor mechanism allograft tensioned tightly in full extension.
. Revision of the tibial and femoral components and reconstruction of the patellar tendon using an extensor mechanism allograft tensioned tightly in full extension.

Correct Answer & Explanation

. Exchange of the modular polyethylene spacer to a thicker insert and reconstruction of the patellar tendon using an extensor mechanism allograft tensioned tightly in full extension.

Explanation

A chronic patellar tendon rupture is a difficult complication to manage. Patients typically present with both inability to extend their leg and instability of the extremity, oftentimes associated with multiple falls. Attempts at secondary repair have been associated with high failure rates, whereas the use of an extensor mechanism allograft has been shown to more effectively restore active extension in a substantial percentage of patients. Important aspects of the technique include fully tensioning the graft in full extension and immobilization of the extremity for 6 to 8 weeks postoperatively to allow for graft healing. Nonsurgical management will not result in an acceptable outcome for a young patient, and attempted secondary repair is associated with a high rate of failure, even when augmented with local tissues. This patient has gross rotational malalignment of the components, and the surgeon faced with this problem should consider obtaining a CT scan to determine component rotation preoperatively.

Question 1197

Topic: 3. Adult Reconstruction (Hip & Knee)
Figures below demonstrate the radiographs obtained from a 56-year-old man with a 3-year history of right groin pain. A comprehensive nonsurgical program has failed, and the patient would like to proceed with total hip arthroplasty. He is seen by a pain management specialist and is currently taking 40 mg of sustained-release morphine twice daily with oxycodone 10 mg 2 to 3 times a day for severe pain. What is the recommended course of action regarding his chronic narcotic use?
. Increase his current opioid medication regimen prior to and after surgery as needed to control his pain.
. Decrease his preoperative opioid use, and work with his pain management physician to decrease his postoperative opioid requirement.
. Avoid using narcotics in the perioperative period to prevent overdose, and use acetaminophen only for pain control.
. Stop all his opioids 5 days before surgery, and place the patient on a morphine pain control pump postoperatively with a basal rate.

Correct Answer & Explanation

. Decrease his preoperative opioid use, and work with his pain management physician to decrease his postoperative opioid requirement.

Explanation

Chronic opioid consumption prior to total joint arthroplasty has been associated with increased pain after surgery, increased opioid requirements, a slower recovery and longer hospital stay, and higher 90-day postoperative complications compared with patients not on chronic opioids preoperatively. The recommendation based on the provided literature is to decrease the patient's narcotic use prior to surgery.

Question 1198

Topic: 3. Adult Reconstruction (Hip & Knee)
Radiographs obtained from a man with progressively worsening right-sided hip pain over the last 8 months. He is 6 feet tall, with a BMI of 51 kg/m2 and reports that his index total hip arthroplasty was performed 8 years ago. The preoperative work-up includes negative infectious laboratory results. What is the most appropriate surgical plan for revision of the femoral component in this patient?
. Superior approach with trochanteric slide
. Direct anterior approach with a chevron modification of the standard greater trochanteric osteotomy
. Lateral approach with a partial greater trochanter osteotomy
. Posterolateral approach with an extended trochanteric osteotomy

Correct Answer & Explanation

. Posterolateral approach with an extended trochanteric osteotomy

Explanation

The patient’s radiographs demonstrate varus femoral remodeling around a broken cylindrical, distally fixed femoral stem. An extended trochanteric osteotomy would aid in the removal of the well-fixed distal segment and enable the safe insertion of the new femoral component. The approach is not the concern in this case, because extended trochanteric osteotomies have been described from the posterior and direct lateral approaches with excellent outcomes and union rates. The key is that the extended osteotomy is necessary and not a trochanteric slide or standard osteotomy.

Question 1199

Topic: 3. Adult Reconstruction (Hip & Knee)
Figure 30 shows the MRI scan of a 68-year-old woman who has left hip pain. What is the most appropriate treatment?
. Open reduction and internal fixation
. Total hip arthroplasty
. Incisional biopsy
. Proximal femoral resection and reconstruction
. Arthrodesis

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

The patient has a large zone of osteonecrosis of the left femoral head. The wedge-shaped zone of decreased signal intensity on the T1 image in the subchondral region of the femoral head is typical. Based on these findings, total hip arthroplasty is the most appropriate treatment. Open reduction and internal fixation will not help this condition. Incisional biopsy is indicated only if the MRI scan shows a probable neoplasm. Resection of the proximal femur is indicated only for aggressive malignancy. Arthrodesis may be considered in a younger patient but not in a 68-year-old individual.

Question 1200

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old healthy man had total knee arthroplasty 18 years ago, and it now is painful. Radiographs reveal aseptic loosening and the range of motion before surgery is 15 to 85 degrees. The strongest indication for performing a tibial tubercle osteotomy to aid in exposure in his knee would be

. patella baja.
. nonresurfaced patella.
. isolated femoral revision.
. noncemented tibial component.
. previous use of the quadriceps turn-down technique.

Correct Answer & Explanation

. patella baja.

Explanation

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