Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 270 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 5381

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 1 shows the radiograph obtained from a 78-year-old woman who has a recent history of increasing

thigh pain 12 years after undergoing total hip arthroplasty. Figure 2 depicts the radiograph obtained after she fell and was unable to ambulate. What is the most appropriate treatment?

. Application of a femoral cable plate
. Application of cerclage-wired double allograft femoral struts
. Femoral revision with an uncemented long stem
. Femoral revision with a cemented long-stem prosthesis

Correct Answer & Explanation

. Application of a femoral cable plate

Explanation

The surgical treatment of periprosthetic fractures of total hip replacement with a loose implant and progressive bone loss is associated with a high complication rate. The recent literature would favor the use of long "Wagner-type" stems, which have a long distal taper that may optimally engage the remaining femoral shaft isthmus. Plating options are problematic, because the intramedullary stem limits the ability to use screws with the plate. Using long distally fixed stems circumvents this problem by enhancingfracture healing and creating a long-term prosthetic solution in these most difficult cases.

Question 5382

Topic: 3. Adult Reconstruction (Hip & Knee)

Early postoperative infections following primary total hip arthroplasty are most likely caused by which

organism?

. Staphylococcus epidermidis
. Streptococcus viridans
. Propionibacterium acnes
. Staphylococcus aureus

Correct Answer & Explanation

. Staphylococcus epidermidis

Explanation

S aureus is the most common organism cultured in early (fewer than 4 weeks postoperative) periprosthetic infections. Methicillin-resistant S aureus is becoming a more common pathogen in certain patient populations. B hemolytic Streptococcus and some gram-negative infections can also be found in early postoperative infections. S epidermidis, S viridans, and P acnes are more commonly found in late (morethan 4 weeks postoperative) infections.

Question 5383

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

. 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

. What is the most appropriate treatment for the fracture below the implant?

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 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 5384

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 1 and 2 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. Which bearing surface is contraindicated for this patient?

. Ceramic-on-ceramic
. Ceramic-on-highly cross-linked polyethylene (HXPE)
. Metal-on-HXPE
. Metal-on-metal

Correct Answer & Explanation

. Ceramic-on-ceramic

Explanation

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 cell counts. 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 5385

Topic: Total Hip Arthroplasty (THA)

Figures 1 and 2 show the radiographs obtained from a 68-year-old morbidly obese man who underwent

left total hip replacement 7 years ago and did well, with no symptoms prior to the current presentation. He recently rose from a seated position and felt a pop in the hip, with immediate pain and inability to bear weight. Any pressure on the left foot now produces a painful, grinding sensation with loss of left hip stability. What is the best next step?

. Revision of the acetabular implant to a constrained bearing with modular exchange of the femoral head and neck
. Revision of the acetabular and femoral implants
. Retention of the acetabular implant with modular exchange of the femoral head and neck
. Revision of the femoral component alone with a new ceramic head

Correct Answer & Explanation

. Revision of the acetabular implant to a constrained bearing with modular exchange of the femoral head and neck

Explanation

The modular femoral stem has fractured. Changing the liner to a constrained design is not warranted at this time based on the information provided. Revision of the acetabular implant is appropriate because of the potential for damage to the existing cup from metal debris and femoral implant contact and to convert from a metal-on-metal articulation. Nonsurgical management would not provide pain relief or improvement; revision of the total hip arthroplasty is recommended. The implant failed in a short time, and retention of the femoral stem is not recommended because of the concern for failure with only a neck exchange. A dual-mobility bearing may be a good option if the surgeon plans to retain the acetabular component. Extended trochanteric osteotomy is a useful technique for the removal of a well-fixed femoral implant. In this patient, femoral stem removal withoutosteotomy would be difficult due to the fracture of the implant’s femoral neck and theinability to gain purchase for extraction.

Question 5386

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures below show the radiographs obtained from a 68-year old man with progressively worsening right

side 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
. 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

. Superior approach with trochanteric

Explanation

Submit AnswerThe patient’s radiographs demonstrate varus femoral remodeling around a broken cylindrical, distally fixed femoral stem. Proximal femoral remodeling around loose or fractured stems occurs in 21% to 42% of femoral revisions, based on the definitions outlined by Foran and associates. In definition 1, varus femoral remodeling occurs when the template falls within 2 mm of the endosteal cortex of the metaphysis on templating with a diaphyseal engaging stem. In definition 2, varus femoral remodeling = when the template crosses the lateral femoral cortex proximally. Based on the templating or drawing a line from the isthmus proximally along the lateral cortex, implantation of a straight stem would perforate the cortex proximally, indicating varus femoral remodeling. 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 (shorter or incomplete trochanteric) osteotomy. These types would not provide access to the well-fixed distal stem, nor would they afford a straight tube in which to insert a new femoral component.

Question 5387

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 1 and 2 show the radiograph and CT obtained from a 78-year-old woman who underwent right

total hip replacement in 1995. She initially did well with no pain. She was last seen 7 years ago and was having mild hip pain at that time. She was found to have a supra-acetabular cyst on radiographs. She has had severe right hip pain for the past 9 months while using a walker for ambulation. The initial blood work reveals an estimated erythrocyte sedimentation rate of 32 mm/hr, a C-reactive protein level of 0.5 mg/L, a serum cobalt level of 0.4 µg/L, and a serum chromium level of 0.6 µg/L. Right hip aspiration is performed, revealing a white blood cell count of 139, 52% neutrophils, and a negative leukocyte esterase test. What is the best next step?

. Acetabular revision, with placement of a custom triflange acetabular component and femoral head exchange
. Removal of the femoral and acetabular components and placement of an antibiotic spacer, with 6 weeks of intravenous antibiotics
. Head and liner exchange and retention of the femoral and acetabular implants with acetabular bone grafting
. Nonsurgical management with the initiation of bisphosphonates and referral to pain management

Correct Answer & Explanation

. Acetabular revision, with placement of a custom triflange acetabular component and femoral head exchange

Explanation

The hip replacement was performed in 1995, during the period when the previous generation of polyethylene was utilized. This polyethylene was subjected to irradiation in air, with subsequent oxidation and consequent osteolysis after implantation. The mechanism of osteolysis begins with the uptake of polyethylene particles by macrophages, which then initiate an inflammatory cascade and the release of osteolytic factors. This cycle continues, with eventual implant loosening and failure. The imaging shows significant osteolysis and raises concern for pelvic discontinuity and acetabular implant failure. The surgical treatment consists of acetabular reconstruction. In this patient, concern exists for discontinuity based on the substantial amount of bone loss and nonsupportive anterior and posterior columns. This scenario requires complex acetabular revision using a custom triflange device, distraction with a jumbo acetabular component, or placement of a porous metal cup/cage construct with augmentation. The laboratory values are not consistent with infection or failure due to metal debris.

Question 5388

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure below shows a cross-table lateral radiograph obtained from a healthy 56-year-old woman with

recurrent hip dislocations 6 months after total hip arthroplasty performed through a posterolateral approach. Each dislocation occurred when she was bending over to put her shoes on or pick something up. She has dislocated four times and has had no pain between dislocations. Abductor strength is 5 out of

5/. The infection work-up is negative. What is the best next step?

. Revision of the acetabulum and evaluation of the femoral stem
. Conversion to a constrained liner
. Gluteus medius repair and application of a hip abductor brace
. Revision to an elevated acetabular polyethylene liner

Correct Answer & Explanation

. Revision of the acetabulum and evaluation of the femoral stem

Explanation

The cross-table lateral radiograph shows that the patient has decreased acetabular anteversion. She is likely impinging on her cup in flexion and levering the femoral component posteriorly. Given a well-fixed and well-aligned femoral component and a negative infection work-up, the preferred treatment is to revise the acetabulum with a goal of increasing acetabular anteversion to avoid prosthetic impingement. Conversion to a constrained or elevated rim liner is suboptimal in this setting, because the problem is impingement. Indications for a constrained liner are neuromuscular compromise, abductor deficiency, or instability despite well-fixed and well-placed components. Given her 5 of 5 abductor strength, gluteusmedius repair is not indicated.

Question 5389

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures below show the radiographs obtained from a 75-year-old woman who underwent right total hip

arthroplasty in 2009. She did well until last month, when a right posterior hip dislocation occurred after she fell from her bed to the floor. Successful closed reduction was performed. She sustained two more posterior dislocations requiring closed reduction under anesthesia. The surgical report from the index arthroplasty notes a 54-mm monoblock acetabular component with a 28-mm inner diameter compression molded polyethylene and a high offset neck cementless stem with a +8-mm length, 28-mm head. What is the best next step?

. Hip spica cast placement
. Acetabular revision arthroplasty
. Resection arthroplasty
. Femoral head revision to a 28-mm diameter, +10-mm length head

Correct Answer & Explanation

. Hip spica cast placement

Explanation

This patient has demonstrated recurrent instability, and her current implants lack the modularity to upsize and improve the head-neck ratio and range to impingement. Given the monoblock acetabular component and a +7-mm neck length, the best option is revision to a large-diameter femoral head or dual-mobility component. Placement of a hip spica cast and resection arthroplasty are unreasonable. Revision to a longer ball length likely would not solve this recurrent instability pattern.

Question 5390

Topic: 3. Adult Reconstruction (Hip & Knee)

According to Musculoskeletal Infection Society (MSIS) guidelines, which set of patient laboratory study

results fits the definition of chronic prosthetic joint infection?

. Erythrocyte sedimentation rate (ESR) 50 mm/hr, C-reactive protein (CRP) 8 mg/L, joint aspiration white blood cell (WBC) count 542, 62% neutrophils, and positive leukocyte esterase
. ESR 42 mm/hr, CRP 12 mg/L, joint aspiration WBC count 3,540, 72% neutrophils, and positive leukocyte esterase
. ESR 20 mm/hr, CRP 15 mg/L, joint aspiration WBC count 4,135, 54% neutrophils, and negativeleukocyte esterase
. ESR 25 mm/hr, CRP 7 mg/L, joint aspiration WBC count 252, 82% neutrophils, and negative leukocyte esterase

Correct Answer & Explanation

. Erythrocyte sedimentation rate (ESR) 50 mm/hr, C-reactive protein (CRP) 8 mg/L, joint aspiration white blood cell (WBC) count 542, 62% neutrophils, and positive leukocyte esterase

Explanation

The MSIS definition of periprosthetic joint infection was updated in 2014 with two major and six minor criteria. The presence of one major criterion or three minor criteria is diagnostic for infection. The major criteria are two positive cultures with the same organism or a draining sinus tract. The current MSIS minor criteria are 1) an elevated ESR (more than 30 mm/hr) and CRP level (more than 10 mg/L), 2) an elevated synovial WBC count (more than 3,000 cells per/microliter), 3) an elevated synovial fluid polymorphonuclear count (more than 80%), 4) a positive histological analysis of periprosthetic tissue, and 5) a single positive culture.

Question 5391

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures below show the AP and lateral radiographs obtained from a 54-year-old woman who has worsening

groin pain 18 months after a primary left total hip arthroplasty. The pain is worst when climbing stairs, when rising from a seated position, and during resisted hip flexion. Her pain improved early after surgery but did

not completely resolve. Her C-reactive protein and erythrocyte sedimentation rate results of less than 1 mg/dL

and 10 mm/hr, respectively, were obtained in the office. What is the best next step?

. MRI with MARS of the left hip
. Revision of the left acetabular component
. Intra-articular ultrasound-guided left hip injection
. Physical therapy for the left hip

Correct Answer & Explanation

. MRI with MARS of the left hip

Explanation

Iliopsoas impingement is a potential cause of persistent groin pain after a total hip arthroplasty. This patient’s history gives groin pain with resisted hip flexion and during activities that require this level of function. The radiographs depict an acetabular component with substantial retroversion. Typical options for the management of iliopsoas tendon impingement include injections, tenotomy, and acetabular revision. Recently, Chalmers and associates reported more predictable groin pain resolution with 8 mm or more of anterior acetabular component when overhang was revised. The radiographs clearly show more retroversion, with a cup prominence of more than 8 mm anteriorly. MRI with MARS could potentially help in the diagnosis of this impingement but would not help in management (option A). An ultrasound- guided injection would need to be administered into the iliopsoas tendon sheath to be of help and, in this case, would likely be performed for diagnostic purposes due to the extreme anterior overhang (option C). Option D would be useful for mild cases of iliopsoas impingement but likely would not help much in this more extreme case.

Question 5392

Topic: Total Hip Arthroplasty (THA)

Figure 1 shows the radiograph obtained from a 67-year-old man recently diagnosed with osteoarthritis, 8

years after receiving a left metal-on-metal total hip arthroplasty (THA). The acetabular component has a modular cobalt alloy acetabular liner. The patient states that he did very well postoperatively, but for the last 6 months has noted worsening pain and swelling in his left hip. Serum metal ion testing reveals a chromium level of 12.4 ng/mL, compared with a normal level of less than 0.3 ng/mL, and a cobalt level of 11.8 ng/mL, compared with a normal level less than 0.7 ng/mL. An MRI with metal artefact reduction sequence (MARS) was performed and is shown in Figure

. What is the most appropriate management at this time?
. Annual monitoring of serum metal ion levels
. Repeated MRI with MARS in 6 months
. Conversion of the THA to a cobalt alloy femoral head and polyethylene bearing
. Conversion of the THA to a ceramic femoral head with an inner titanium sleeve and polyethylene bearing

Correct Answer & Explanation

. What is the most appropriate management at this time?

Explanation

Metal-on-metal THA was initially introduced in the 1990s, with the proposed advantages of decreased wear and improved stability. However, catastrophic adverse local tissue reactions associated with their use has raised numerous concerns. The work-up of a patient with a prior metal-on-metal total hip arthroplasty involves a thorough history and physical examination; blood analysis, including the erythrocyte sedimentation rate, C-reactive protein, and metal ion levels; and secondary imaging, including ultrasonography, CT, and MRI. In a patient with clinical symptoms, elevated metal ion levels, and a large fluid collection seen on MRI, the most appropriate treatment would be removal of the metal-on-metal bearing. Given the presence of an adverse reaction involving cobalt and chromium, a revision ceramic head may be most appropriate to avoid the potential of trunnion-associated corrosion.

Question 5393

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures below depict the radiographs obtained from a 76-year-old woman with a painful total knee

arthroplasty. She describes an uneventful recovery with no wound-healing issues and was pain free for the first 10 years. Although reporting no trauma or inciting event, she now describes pain in the entire knee that is most severe with her first few steps. She has begun to notice night pain and, more recently, constant swelling. What is the most appropriate work-up at this time?

. Knee aspiration with cell count/cultures, C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), CT
. Knee aspiration with cell count/cultures, CRP, ESR
. Fresh-frozen specimen at the time of revision knee arthroplasty only
. Technetium-99m bone scan, knee aspiration with cell count/cultures

Correct Answer & Explanation

. Knee aspiration with cell count/cultures, C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), CT

Explanation

An evaluation of the painful total knee must be supported by an understanding of the potential etiologies of pain. They may include, aseptic loosening, infection, osteolysis, gap imbalance, referred pain, stiffness, and complex regional pain syndrome. In this case, the patient demonstrates start-up pain and had no prior history of infections. Her radiographs show subsidence of the tibia, indicating a loose prosthesis. Knowing that the prosthesis is already loose precludes the need for a bone scan. It is, however, important to rule out infection in this case; therefore, CRP and ESR testing is essential. Aspiration is also recommended when going into knee arthroplasty, and infection is a concern.

Question 5394

Topic: 3. Adult Reconstruction (Hip & Knee)
The direct anterior (Smith-Petersen) approach to hip arthroplasty is most commonly associated with injury to what nerve?
. Lateral femoral cutaneous
. Sciatic
. Pudendal
. Superior gluteal

Correct Answer & Explanation

. Lateral femoral cutaneous

Explanation

Some authors have reported the incidence of lateral femoral cutaneous nerve neuropraxia following hip arthroplasty with the direct anterior approach to be near 80%, but resolution of the sensory deficits has been observed in most patients over time. Femoral nerve palsy has been reported to occur in 0.64% to 2.3% of direct lateral (Hardinge) and anterolateral (Watson-Jones) approaches, and the superior gluteal nerve may be injured with proximal extension of the abductor muscular dissection. The posterior approach has been reported to be associated with sciatic nerve injury, especially in cases of dysplasia. Pudendal nerve injury has not been reported with the anterior, anterolateral, direct lateral, or posterior approaches to hip arthroplasty. It has been reported following hip arthroscopy and the use of a traction table, however.

Question 5395

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old woman is referred for evaluation of a painful knee replacement. She underwent total knee

arthroplasty (TKA) more than 1 year ago without perioperative complications but has had consistent pain since the surgery. The patient’s preoperative radiographs and postoperative radiographs are shown in Figures below. Examination reveals medial laxity during valgus stress testing and range of motion of 0° to 70°. Her erythrocyte sedimentation rate and C-reactive protein level are normal. What is the best next step?

. Unloader brace
. Distal femoral osteotomy
. Open arthrofibrosis debridement with lateral ligament balancing and polyethylene exchange
. Revision TKA of both the femoral and tibial components

Correct Answer & Explanation

. Unloader brace

Explanation

The radiographs show substantial valgus malalignment of the femoral component, with lateral mechanical axis deviation. Clinically, by examination she displays instability and stiffness as a result. Revision knee replacement is appropriate and should consist of total revision to stemmed femoral and tibial components with a varus-valgus constrained insert, given the likely attenuation of the medial collateral ligament. Open debridement with ligament balancing and polyethylene exchange do not address the underlying cause and are inappropriate. Distal femoral osteotomy is not useful in the setting of previous total knee replacement.Nonsurgical treatment with an unloader brace would be ineffective in correcting the alignment.

Question 5396

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old man has a draining sinus and recurrent infection of his right total knee arthroplasty. He has

had two prior revision surgeries after the primary procedure and three other surgeries before his initial replacement, including a proximal tibial osteotomy and subsequent hardware removal. On clinical examination, he has a draining sinus in the mid portion of his surgical scar and a range of motion of 5° to

85°. AP and lateral radiographs of the right knee are shown in Figures below. During surgery, the femoral component is found to be grossly loose, but the tibial component is well fixed. What is the most appropriate extensile approach that would provide adequate exposure and aid in tibial component extraction?

. Extended medial parapatellar approach
. Quadriceps snip
. Extended tibial tubercle osteotomy
. Medial epicondyle osteotomy

Correct Answer & Explanation

. Extended medial parapatellar approach

Explanation

Extended tibial tubercle osteotomy is an extensile approach to revision total knee arthroplasty that affords excellent exposure and can facilitate removal of tibial sleeves and cones. This patient has had multiple surgeries, including a proximal tibial osteotomy, as well as poor range of motion, patella baja, and a well- fixed metaphyseal sleeve component. Classically, an extended tibial tubercle osteotomy provides outstanding exposure for component removal in the setting of prior high tibial osteotomy and patella baja. For this patient, it is important to recognize the patella baja on the radiographs, as well as the tibial sleeve. In many of these cases the osteotomy provides access to the sleeve to help with extraction, because the stem will not pull through the sleeve or detach from the tray to allow visualization of the sleeve. The extended medial parapatellar approach is just a long medial approach that typically yields good exposurebut would not help with the patella baja or extraction of the tibial sleeve. The quadriceps snip would give good exposure to the knee but would not aid in tibial component removal. Lastly, the medial epicondyle osteotomy could help with exposure and tensioning of the medial complex of the knee but would not helpwith tibial component extraction.

Question 5397

Topic: 3. Adult Reconstruction (Hip & Knee)
A 58-year-old woman underwent a left total knee arthroplasty 6 years ago. She initially did well after surgery but sustained a fall 2 months ago while at work. She now describes left knee pain and instability and an inability to straighten her knee since the fall. She has been using a hinged knee brace, which provides partial support. On examination, she has passive range of motion of 0° to 115° and active range of motion of 80° to 115°. Her radiographs are shown in figures below. What is the best option for the restoration of her function?
. Revision total knee arthroplasty with placement of a hinge constrained device
. Patellar tendon repair with nonabsorbable suture and patellar resurfacing
. Hinged knee brace with drop lock design to restore stability during ambulation
. Extensor mechanism reconstruction using synthetic mesh or allograft

Correct Answer & Explanation

. Extensor mechanism reconstruction using synthetic mesh or allograft

Explanation

The patient has an extensor mechanism disruption with patellar tendon rupture. This injury is treated with extensor mechanism reconstruction in the setting of previous total knee arthroplasty. There is a reported high failure rate with attempted repair. Revision to hinge knee arthroplasty would provide implant stability but would not restore the extensor mechanism. The patient is relatively young and is working, so reconstruction would offer better long-term function than a drop lock brace, which can be better used in low-functioning patients with this type of injury. Extensor mechanism reconstruction historically has been accomplished with allograft material, but a novel technique using synthetic mesh also has proved successful in treating this difficult problem.

Question 5398

Topic: 3. Adult Reconstruction (Hip & Knee)
Figures below show the radiographs and the CT obtained from a 58-year-old woman who underwent cementless left total hip arthroplasty. Nine months after surgery, she continued to have groin pain when actively flexing her hip. She has trouble walking up stairs and getting out of her car. What is the most likely diagnosis?
. Trochanteric bursitis
. Femoral component loosening
. Iliopsoas tendonitis
. Acetabular component loosening

Correct Answer & Explanation

. Iliopsoas tendonitis

Explanation

Groin pain after total hip replacement has a number of possible causes, and an exact diagnosis may remain elusive in some patients. Infection should be ruled out with laboratory studies and, if indicated, diagnostic aspiration of the hip joint. Implant loosening should be evaluated by plain radiograph and bone scan, if indicated. Synovitis resulting from wear debris should be considered in patients with polyethylene liners who experience late-onset symptoms or in any patient with a metal-on-metal bearing. This patient's symptoms are classic for iliopsoas tendonitis. Physical examination usually reveals pain and weakness with resisted hip flexion. A cross-table lateral radiograph and CT show that the anterior edge of the acetabulum protrudes beyond the anterior wall, thereby acting as a source of iliopsoas tendon irritation. In such cases, acetabular component revision and repositioning are indicated. Fluoroscope-guided iliopsoas cortisone injection can help to establish the diagnosis and relieve groin pain. If the acetabular component is well positioned, then iliopsoas tenotomy should be considered.

Question 5399

Topic: 3. Adult Reconstruction (Hip & Knee)
A 72-year-old woman is scheduled to undergo right total hip arthroplasty. Her preoperative radiograph is shown in the figure below. To avoid increasing this patient’s combined offset while maintaining her leg length, what is the most appropriate surgical plan?
. Lateralize the acetabular component, use a low offset femoral component, and make a shorter neck cut
. Medialize the acetabular component, use a low offset femoral component, and make a longer neck cut
. Lateralize the acetabular component, use a high offset femoral component, and make a shorter neck cut
. Medialize the acetabular component, use a high offset femoral component, and make a longer neck cut

Correct Answer & Explanation

. Medialize the acetabular component, use a low offset femoral component, and make a longer neck cut

Explanation

The management of patients with proximal femoral deformity can be difficult. Appropriate implant selection and preoperative templating are critical. In this patient, it would be difficult to avoid increasing the combined offset by too much, which could contribute to the overtensioning of the soft tissues and trochanteric pain. By medializing the acetabular component (decreasing the combined offset), using a low offset femoral component or a cemented component placed more valgus (decreasing the combined offset), and making a longer neck cut (to avoid shortening of the lower extremity), restoration of the patient’s native offset and leg length can be achieved.

Question 5400

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

. Increase his current opioid medication regimen prior to and after surgery as needed to control his pain.

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. Based on this information, Nguyen and associates performed a study in three patient groups that included 1) chronic opioid users who underwent no preoperative intervention, 2) chronic opioid users who were weaned down to 50% of their prior opioid regimen, and 3) patients who were not chronic opioid users. The authors found that the reduction of preoperative opioid use improved postoperative function, pain, and recovery and that the weaned group performed more like the opioid naive group than the chronic opioid usergroup. Increasing opioid use prior to surgery in this patient would make it more difficult to control pain after surgery. Stopping all of his opioids just prior to surgery would place the patient at substantial risk for opioid withdrawal and is not recommended. Avoiding the use of all narcotics and using only acetaminophen postoperatively is very unlikely to provide appropriate pain relief in a chronic opioid user. The recommendation based on the provided literature is to decrease the patient's narcotic use prior tosurgery.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page