Case Challenges: What Would You Do?

Case Challenges: What Would You Do? Kelly G. Vince, MD, FRCS(C) Is a tragically bad result simply unavoidable or were there choices along the way that might have lead to success? At what point does a difficult case require a maximally aggressive approach and, by contrast, when should the surgeon abandon hope of conventional success and recommend arthrodesis or amputation? Three cases highlight the “end game” scenario in knee arthroplasty surgery and the difficulty in knowing when a successful reimplantation is unlikely, when ambitious surgery puts the patient’s life at risk, and when the remaining options are only: permanent resection arthroplasty, arthrodesis, or amputation. Semin Arthro 22:197-211 © 2011 Elsevier Inc. All rights reserved. KEYWORDS knee, arthroplasty, failure, revision, arthrodesis, infection, fracture

Moderator: Kelly G. Vince, MD, FRCS(C) Panelists: Robert B. Bourne, MD, FRCS(C)—Professor of Orthopaedic Surgery, Division of Orthopaedic Surgery, University Hospital, University of Western Ontario, London, Ontario, Canada. Christopher A.F. Dodd, FRCS—Consultant Orthopaedic Surgeon, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Headington, Oxford, UK. Aaron A. Hofmann, MD—Professor of Orthopaedic Surgery, University of Utah Orthopaedic Center, Salt Lake City, UT. Aaron G. Rosenberg, MD—Professor of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL. Bernard N. Stulberg, MD—Professor of Surgery, Department of Orthopaedic Surgery, Cleveland Clinic Orthopaedic & Rheumatologic Institute, Cleveland, OH.

Case 1 MODERATOR: I understand the physicist Niels Bohr said: “an expert is a man who has made all the mistakes which can be made, in a narrow field.” We are here with a panel of experts to discuss some very difficult, and I am afraid very somber cases. I would like to proceed differently than usual, by starting with the final, tragic outcome of each case and proceeding backwards in time, to try and understand exactly Whangarei Hospital, Northland District Health Board, Whangarei, New Zealand. Address reprint requests to Kelly G. Vince, MD, FRCS(C), 118 Crane Road, RD 1, Kamo, 0185, New Zealand. E-mail: [email protected]

1045-4527/11/$-see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1053/j.sart.2011.07.016

how things ended badly. In each case, was it simply unavoidable fate or were there different choices that might have ended better? These cases have passed through or have entered the “end game” scenario, where only 4 options are conceivable: reimplantation, arthrodesis, permanent resection arthroplasty, or sadly, an amputation. Sometimes, the outcome is even worse. I doubt there can be any brilliant surgeries proposed; these will be assessments after the catastrophe where constructive criticism and insight may help us all to care for our next difficult case. When possible, I would ask our panel to assess what was done accordingly: a. b. c. d.

What I would have done. Reasonable but not what I would have done. Defensible, but definitely not my choice. Surgeon exposed to liability.

(Note: Cases have been presented to the panel in reverse chronological order, starting with the most recent images. Figures 1-5 pertain to case 1. Figures 1O-R plus Figures 2A and B are examples of similar cases in the published literature.)

Case 1 We start with the most discouraging case, a patient who ultimately died after total knee arthroplasty (TKA). This occurred 2 weeks after the surgery we see here (Fig. 1A and B), a planned third debridement by a very talented and welltrained young surgeon who accepted her care despite the profound difficulties. We see on the left an antibiotic-impregnated spacer that spans the space from the proximal tibia to the proximal femur. An infected knee arthroplasty and 197

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198 the hardware from a supracondylar periprosthetic fracture and a proximal femur fracture have been removed. The wound at this last surgery is seen on the right, with wellperfused skin margins after debridement. This was to have

Figure 1

been final preparation for the soft-tissue transfer that was never performed. Remember that we are proceeding “back in time” so immediately preceding we see the wound with an eschar over

Case challenges: what would you do?

Figure 1 (Continued) (A) This patient eventually died of complications of surgery. Intraoperative photograph of planned third debridement of a resection arthroplasty. From proximal (top) to distal (bottom) the distal two-thirds of the femur has been removed and temporarily replaced with a stainless steel surgical spinal rod covered completely with antibiotic impregnated methacrylate bone cement, as the first stage of a planned 2-stage reimplantation protocol. (B) Debrided wound, eschar removed, in preparation for grafting, after multiple debridements and with a resection arthroplasty in place. (C) Intraoperative photograph with patient under anesthesia before debridement of eschar and repeat deep debridement. Arrow indicates close-up of eschar. (D) Intraoperative radiograph after initial removal of prosthesis and fracture fixation hardware with a stainless steel spinal rod that has been covered with antibiotic-impregnated methacrylate cement and positioned to maintain relationship of remaining proximal femur and proximal tibia. Towel clip is apparent in upper right on surgical drapes. (E) Postoperative lateral radiograph of resection arthroplasty with spinal rod as part of cement spacer. (F) Surgical specimen after first resection arthroplasty where primary TKA prosthesis, supracondylar locking rod, and necrotic infected distal femoral bone have been removed. (G) Lateral radiograph after initial debridement showing residual tibia and patella. The distal two-thirds of the femur have been removed to treat infection. Note extensor mechanism is intact. (H) Anteroposterior radiograph at same time as (G). (I) In surgery immediately before preparation for planned second debridement after removal of components at initial debridement. Extended anterior knee incision from TKA and lateral incision from plating of proximal femur periprosthetic fracture converge on a large area of skin necrosis. (J) AP radiograph of proximal femur at the time of initial presentation to referral center with infected, dual periprosthetic femur fractures complicating a TKA. (K) Clinical photograph of chronically draining sinus on the anterior thigh at the time of initial presentation. There is a nonunion after a proximal femur fracture complicating a supracondylar nail for a periprosthetic fracture above TKA. The entire construct is infected. (L) Clinical photograph at initial presentation of the lateral right thigh. The hip is to the left and knee is to the right. The entire wound from fixation of a proximal femur fracture has granulated, after weeks of drainage at the original hospital. Drainage persists and original prosthesis and fixation hardware are in place. (M) AP radiograph of the distal thigh on initial presentation with infected TKA and supracondylar locking nail and screws from periprosthetic fracture. The distal portion of the plate for a dynamic hip screw is apparent at top. Multiple cerclage wires in place. (N) Lateral radiograph of proximal femur showing collapse of subtrochanteric fracture that followed fixation of supracondylar periprosthetic fracture. (O) Exemplary case example from the literature,2 asking if this approach to infected failure would be applicable. This AP radiograph shows an infected long-stem revision THA with periprosthetic fracture and extensive bone loss. (Reprinted with permission.) (P) Exemplary case example labeled “spacer,”2 showing a temporary long-stem prosthesis covered with antibiotic impregnated bone cement to maintain position in this resection arthroplasty. (Reprinted with permission.) (Q, R) Exemplary case example. Eventual reconstruction after resection arthroplasty with “total femur” prosthesis and hinged TKA.2 (Reprinted with permission.) (S) Composite AP radiograph, before referral, of dynamic hip screw to treat a subtrochanteric fracture that followed a retrograde locking nail for a supracondylar fracture above a TKA. Fixation has been supplemented with cerclage wires and strut allografts.

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Figure 2 (A) Unassembled, modular intramedullary total femur replacement (IMTF)4 shown to the panel for consideration in our case challenge. (Reprinted with permission.) (B) Assembled IMTF.

the confluence of the anterior TKA incision and the distal extent of the lateral hip incision. The inset is a close-up of this area about to be re-debrided (Fig. 1C). The radiograph shows the results of the first debridement and hardware removal (Fig. 1D). The residual proximal femur is outlined in a dotted

line and a towel clip is apparent on the drapes. Inserted into the proximal femur is a stainless steel rod that has been completely enveloped in antibiotic impregnated polymethylmethacrylate. This rod extends distally past the resected knee joint and into the tibia. Antibiotic impregnated cement has been formed into dowels and inserted into the medullary canal of the tibia. On the right (Fig. 1E) we see the lateral view of the knee, with an intact patella in a relatively normal position, implying that the extensor has the potential to function. The specimen removed at the first debridement (Fig. 1F) includes the femoral component, the distal two-thirds of the femur, and a supracondylar nail. This radiograph shows what was left after the very thorough first debridement, before the “mega spacer” was inserted (Fig. 1G and H). An earlier clinical photograph shows the state of the wound some time after removal of hardware (Fig. 1I). An even earlier clinical photograph (Fig. 1J-L) shows the patient’s limb on initial presentation to our referral center with an infected TKA and infected hardware for 2 periprosthetic femur fractures (Fig. 1M and N). The patient was on chronic suppressive antibiotics and actively infected. I put the question to our panel: “How would you proceed, on receiving this complex problem, with the infected arthroplasty and hardware in place?” ROSENBERG: This is the sort of situation where you must consider the patient’s underlying health issues as your biggest deciding factor. If this were in an otherwise healthy young patient, I would try to salvage the limb in any of a number of ways. The first step would be to clear the sepsis, get appropriate soft-tissue cover, and determine what can be done from there—assuming everything is healthy. In an elderly individual with medical comorbidities and several surgeries required, I would ask; “with the best recon-

Figure 3 (A) AP radiograph of the case under discussion with a TKA complicated by a periprosthetic fracture treated with a retrograde supracondylar nail, cerclage wires, and strut allograft. (B) Close-up of AP radiograph (A) of the most proximal locking screw demonstrating a cortical lucency that probably coincides with an initial unsuccessful drill hole. (C) Same region depicted in (B), showing femur fracture through the drill hole. (D) Lateral radiograph showing anterior lucency and eventual fracture site.

Case challenges: what would you do?

Figure 4 (A) AP radiograph of primary TKA with acute supracondylar fracture, the complication that initiated a cascade of problems that ultimately proved fatal. (B) Lateral radiograph of displaced periprosthetic fracture. (C) AP radiograph of the right TKA soon after surgery. No lateral projection was provided. The location of the fibular head, behind the lateral aspect of the lateral tibia, suggests that the leg was rotated externally for the study. However, the symmetric view of the tibial component itself would be consistent with an internal rotation of the tibial component, known to be associated with poor postop motion. (D) AP radiograph of contralateral, unaffected left TKA with good alignment and fixation. (E) Lateral radiograph of contralateral TKA with a femoral component in slightly “flexed” position, with an anterior bone cut that has exposed cancellous bone for a distance of about 2 cm. Although not a “notch,” this may be a stress riser.

struction I could get, would they ever walk again?” The answer is not likely to be “yes.” Then, we would be facing a modified hip disarticulation to treat an entirely infected femur with an open wound, et cetera. MODERATOR: Bob Bourne, what would you outline to this patient, with a chronically infected arthroplasty and periprosthetic fractures at this first meeting? BOURNE: It’s a very tough issue. As Aaron said, you’re not just treating an infection; you must look at the host. This is a patient and family you must get to know well. They have to know the risks of what you’re proposing and the benefits, which may be very few. So this is a tough situation. We have

201 just reviewed failed, two-stage exchanges for infection, and it’s not a very happy tale (the role of host factors in the infected arthroplasty has been studied in-depth by Cierny et al.1—KGV). MODERATOR: That’s an excellent point. We tend to group all 2-stage reimplantations into the same basket and assume the results are equally good for everyone, but they aren’t. Aaron, what are you going to tell the family? ROSENBERG: You have to talk to the patient about how this femur is infected from top to bottom. It’s all interconnected. From that very first interaction with the patient and their family, I would discuss amputation, because not all problems are solvable. We can’t necessarily treat this patient with the usual limb salvage. MODERATOR: So you would consider hip disarticulation? ROSENBERG: You might be able to save the proximal femur, but the end result for this patient is nonambulation and a wheelchair. Whether you resect below the lesser trochanter, which gives some seated weight-bearing capability, or do a hip disarticulation, the patient is never going to ambulate with either option. MODERATOR: Bernie, would you have contemplated the “mega-spacer” that had been used or would you have recommended an amputation primarily? Was it a mistake to try to salvage the leg? STULBERG: I would place the strategy in the B or C category you described; aggressive debridement with a spacer was reasonable but not what I would have done. When you look at the femur above that knee, this is a patient for whom the host issues are huge. With a patient who’s not walking— you’re losing every time you operate. My tumor surgeon colleagues would either debride or remove the whole femur. But I personally would have probably—it’s technically an OK thing to do, but I think this particular patient, this particular host . . . (expressing doubt about being able to cure this infection—KGV).

Figure 5 Diagram illustrating the triad of risk factors that contribute to supracondylar fracture: 1. osteoporosis, 2. notch or stress riser, and 3. stiffness. When the bone is weak and the patient has limited motion, the knee may reach the limits of flexion with a simple stumble. If the TKA will not bend further, the femur may yield.

202 MODERATOR: Chris, it’s starting to sound like basic principles are failing us here. Is not the principle in the treatment of periprosthetic infection to remove the hardware and debride aggressively? DODD: Yeah. I would assess this strategy at your option C— defensible, but not my choice. You clearly need to talk with this patient about a hip disarticulation. I think it would be very difficult to save the proximal femur, and you would need to be very aggressive. MODERATOR: I conclude that our panel feels in this case that the standard principles of removal of hardware and aggressive debridement are not likely to work, so amputation is preferred. Consider this other case, published by Sherman and colleagues.2 On the left (Fig. 1O) is an infected long-stem total hip arthroplasty (THA); in the center (Fig. 1P), a long antibiotic impregnated spacer after debridement, and on the right, a combined THA (Fig. 1Q) and TKA (Fig. 1R) with total femur replacement—a mega-prosthesis. Would you reserve this, Aaron, for the healthier patient? Is our patient not a candidate because of comorbidities? ROSENBERG: In retrospect, this patient probably wasn’t a good candidate. I think you have to add up a number of factors. I believe Eduardo Salvati developed an infection score, and a patient could accumulate a high score, indicating high risk, by having multiple complicating factors, including immunosuppression, bad soft tissues, medical comorbidities, a poor response to previous antibiotics in terms of nephrotoxicity.3 You have to weigh all these things very carefully. And while you can present a case or 2 where massive reconstruction worked out well, all of us have cases where because we were pushed by the family and the patient, who ultimately has to make the decision, people lost their lives because they should have had an amputation. MODERATOR: I’ve been doing these panels for a while now and have finally presented a case where our experts are not looking for ever more creative solutions. All of you are being very, very pragmatic. Here’s the same patient, earlier. A supracondylar periprosthetic fracture was treated with a retrograde nail, inserted from the knee. That procedure was complicated by a second fracture at the proximal tip of the rod. This second fracture was treated with a DHS (dynamic hip screw and plate). Was the second fracture fixation hardware reasonable treatment (Fig. 1S)? At what point would total femur reconstruction be appropriate? Consider another case, published from the University of Utah4 (Fig. 2A and B). Would any of you have recommended this leap to the total femur when the second fracture occurred? Aaron, yes or no? ROSENBERG: I would say yes. MODERATOR: Bob, yes? BOURNE: Yeah, but I’ve had 2 in 33 years of practice, so it’s not very common. MODERATOR: Aaron Hofmann? HOFMANN: I have done exactly 2 as well. In fact, Chris Peters, who is the author of the paper you are quoting,4 practices with me and we have both done these reconstructions.

K.G. Vince MODERATOR: Total femoral replacement, with ipsilateral THA and TKA, would have been an option for our panel after the second periprosthetic fracture but before there was infection. Once infection set in, everyone has been concerned about the need for amputation. Here we see the first surgery for the original supracondylar fracture—a locked supracondylar nail (Fig. 3A-D). When you look carefully at these x-rays, it seems there was more than 1 screw hole created. It is difficult with an obese patient to ensure that holes are always drilled accurately for locking screws. However, it seems the second fracture went right through the abandoned screw hole. Was this preventable? Is this something that a surgeon is liable for, an extra screw hole that then becomes the fracture site? ROSENBERG: No. MODERATOR: Fair enough. Now consider the original fracture, a fairly standard periprosthetic fracture in the supracondylar region (Fig. 4A and B). Is a supracondylar nail still within the standard of care for this fracture? Aaron? ROSENBERG: I don’t know what standard of care means. MODERATOR: OK. ROSENBERG: I kind of feel like I’m on the stand here! MODERATOR: I’m not here to make you feel comfortable, Aaron! ROSENBERG: It’s not my comfort that I’m worried about! I think a locking plate might be more a more contemporary solution. However, the distal fragment looks very small and difficult to fix. You might need cement reinforcement. Either that, or I would choose a distal femoral replacement prosthesis. MODERATOR: Aaron (Hofmann), is that fracture too distal for a locking plate? HOFMANN: For a locking nail or locking plate? I prefer a locking plate. MODERATOR: Chris, do you think it’s too distal to fix? DODD: From what I can see, it is too distal. It’s comminuted, isn’t it? It’s in bits. ROSENBERG: Yeah, it looks comminuted, very distal and osteopenic. Those are all, to me, indications to do a distal femoral replacement. I’m not going to talk about standard of care. I don’t think that’s appropriate. MODERATOR: OK. Fair enough. In this April 2010 study5 of supracondylar fractures treated with lateral locking plates, Streubel and colleagues concluded: “extreme distal periprosthetic supracondylar femur fractures are not a contraindication to lateral locked plating.” Clearly, the literature supports both locked nail or plating techniques as satisfying the standard of care for periprosthetic supracondylar fractures.6,7 Next we see radiographs showing the early post TKA films, but only for the contralateral, unaffected knee (Fig. 4C-E). The lateral view (where we might look for a supracondylar notch) of the infected knee with the periprosthetic fracture was not included. For the knee radiograph that we have, does the contour on the anterior femur proximal to the femoral component constitute a notch, Bernie? Do you see the anterior femoral bone cut for a femoral component in a flexed position?

Case challenges: what would you do? STULBERG: Could be, but I’m not too worried about it. There is one comment about the right knee. MODERATOR: Yes? STULBERG: Does the prosthesis on the right have an intracondylar opening to admit a rod? HOFMANN: That prosthesis has a big intracondylar notch (an essential feature for passage of a locked supracondylar nail is an open intracondylar “box” large enough to admit a supracondylar nail8—KGV). MODERATOR: The treating surgeons appear to have been very successful with introduction of the locked nail. DODD: Doesn’t seem to, what I can see of it. ROSENBERG: I’m reminded of the scene from Crocodile Dundee where he says: “that’s not a knife, this is a knife.” I mean, that’s not much of a notch, man. MODERATOR: OK. ROSENBERG: I think they call that a “blend” in New York, not a “notch.” MODERATOR: Exactly. The role of “notches” in supracondylar fractures has been discussed extensively in the literature. A recent paper from the UK concluded that there’s no relationship between minimal anterior femoral notching and supracondylar fracture of the femur.9 I think that’s reassuring, but returning to our case, why did the femur fracture? Was it preventable? Could something different have been done to avoid this? Should we recognize when a patient is high risk and “stem” their femoral component? ROSENBERG: You could do that. The Mayo Clinic describes fracture and infection as the two major reasons for revision and this is a high-risk patient. MODERATOR: Does anyone on the panel choose a stemmed prosthesis for primary surgery because they’re worried about supracondylar fracture? HOFMANN: It’s very rare, but if you notch the anterior cortex such that there is a step-off in the cortex into the intramedullary space, that would be a big notch. I would prefer a prosthesis with a stem for that type of notch. MODERATOR: OK. Bob, do you ever put in a stem because you’re trying to prevent a fracture? BOURNE: Sure. If you had a previous plate that had to be removed, I would prefer a prosthesis with a stem attached to it. In the rare instance that you get a crack in one of the femoral condyles, you certainly would want a stemmed component. I think you have to be prepared to do it occasionally, but not very often. MODERATOR: Aaron, would you go to surgery with the intention of using a stemmed component because you were worried about bone quality? ROSENBERG: No. Only in revision surgery would I plan a stemmed femoral component for every case. In a primary surgery, almost never. MODERATOR: I feel the risk of periprosthetic fracture is increased by three factors: osteoporosis, a supracondylar notch, and stiffness (Fig. 5). The stiff knee that flexes only to a certain point is at risk when the patient stumbles. The knee flexes to the limit, then something has to give and the femur may fracture. Chris, do you ever go to surgery so worried about the possibility of fracture that you use a stem?

203 DODD: I can’t remember the last time I did. I suppose I am very cavalier about it. In fact, I’ve never used a stemmed component in a primary knee, but I have had 2 fractures. MODERATOR: Bernie? STULBERG: Well, I think there are some knees where you might use a stem for other reasons, not necessarily fracture. There is a number associated with the depth of the notch that increases risk of fracture. David Backstein and colleagues at the University of Toronto published a nice laboratory study on that.10 (The paper referred to concluded that “anterior femoral notches greater than 3 mm, with sharp corners located directly at the proximal end of the prosthesis produced the highest stress concentrations and may lead to a significant risk of periprosthetic fracture.”—KGV). MODERATOR: I leave you with this consideration. The supracondylar fracture in this case originated not only from osteoporotic bone, but also from relatively poor flexion and an “incursion” if not a notch on the anterior femoral cortex. Let’s say the femoral component was the correct size for the patient but was translated slightly posteriorly and flexed slightly, making the flexion gap tight and decreasing flexion. This could have originated with most contemporary intramedullary instrument systems, if the entry hole were created in the center of the distal femur and the intramedullary (IM) guide had the space to angulate into flexion within a spacious canal. Could this ultimately fatal cascade have originated with the choice of entry hole in the first step of the arthroplasty?

Case 2 MODERATOR: This patient is a 78-year-old male, who eventually underwent an arthrodesis 2 years after TKA to treat a periprosthetic infection. He had undergone a 2-stage protocol 2 times, without eradication of infection. After the second, aspiration of the TKA remained positive for infection. Here we see the technique for fusion (Fig. 6A). What’s your technique, Aaron (Rosenberg), for arthrodesis? Or can you remember the last time you fused a total knee? I cannot. ROSENBERG: I used to do a lot of these, and I preferred an arthrodesis nail. I did not like the nails that connected at the knee; I preferred nails with locking screws proximally and distally. I rarely needed to lock them distally but usually locked them proximally. It was a very effective technique for getting an arthrodesis even with extensive bone loss. MODERATOR: Bob, what is your technique for arthrodesing a knee after failed TKA? BOURNE: Exactly as we see in this case. I’ve tried most of them, but an unlinked IM nail worked the best in my hands. MODERATOR: I rarely do this operation because it’s always 1 that could only have been done “2 surgeries ago.” By the time the patient agrees to a fusion, it’s too late; there is not enough bone or infection has become too firmly entrenched. Bargiotas and colleagues described a technique in 2007 for knee fusion in the presence of deficient bone. Acetabular and femoral head reamers are used to shave the bone ends and then an intramedullary rod stabilizes the joint11

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Case challenges: what would you do? (Fig. 6B and C). However, it is so difficult for a patient to function in this world with an arthrodesed knee that few agree to the procedure. Returning to our patient, if we go back in time, before the fusion Steinman pins were added to the resection to ensure that the spacer would not dislocate. These pins extend proximally into the femur and distally into the tibia. Two screws and the distal end of a locking nail are visible in the knee radiograph. This nail was used to treat a subtrochanteric fracture that occurred after the TKA but before the first resection arthroplasty. This is the construct we see (Fig. 6D and E) immediately before the arthrodesis. The first two-stage protocol was interrupted by dislocation of the spacer, so a second one was placed (Fig. 6F and G). At the conclusion of antibiotic therapy, cultures remained positive. Chris, what are your thoughts about this infected case? DODD: Well, if you’re worried about instability of the spacer, then certainly you need to try to have a mechanism for preventing dislocation. The options for a more stabilized spacer are limited by the IM nail, so a technique of docking a shortened rod into that other one is quite sensible. MODERATOR: Is this spacer technique something you would do? DODD: Yeah. MODERATOR: OK. Bernie? STULBERG: I’d also prefer to bridge the knee with Rush rods or something inexpensive for this temporary application. MODERATOR: OK. Aaron? HOFMANN: I wouldn’t bridge it. If you’re trying to save the knee and you’re doing a 2-stage spacer, I’d do an articulating spacer. I’d do something that moves.

205 MODERATOR: Do you feel there’s enough bone there for an articulating spacer? HOFMANN: Yes, I think so. MODERATOR: And would the articulating spacer work well with the rod above it? HOFMANN: Sure. MODERATOR: Bob? BOURNE: I would use an articulating spacer. MODERATOR: Articulating spacers, Aaron? ROSENBERG: That’s my preference, in general, articular. DODD: I thought you said it was unstable, though? MODERATOR: Yes. The first spacer that the surgeon put in popped out. DODD: Right. So you’d be worried about another 1 popping out too. HOFMANN: It was meant to move I think. ROSENBERG: You can make crummy spacers that dislocate easily, and you can have patients that no matter how good the quality of the spacer is, they’re going to dislocate. I think it’s often reasonable to put patients in an unlocked hinged knee brace if you’re trying to get motion. MODERATOR: I’m interested that no one commented on the fact that the rods crossing the knee were not encased in bone cement. I use rods for infected revisions where you need to bridge extensive bone loss. I would always bury them in cement to avoid a foreign surface where bacteria might establish a biofilm. Anybody? DODD: I agree with you. MODERATOR: Aaron, you made the point earlier, about having 1 incision and so 1 infection. With the IM rod for a proximal femur fracture in place, everything is in in continu-

Figure 6 Case 2. (A) An arthrodesis, using a long intramedullary rod, as shown on this lateral radiographic projection from an intraoperative image intensifier view. Fusion was selected over reimplantation due to persistently positive cultures after 2 debridements. Whether infection recurred after this procedure is as yet unknown. (B, C) Images reproduced from the literature11 with permission and presented to panel for discussion. This technique of knee arthrodesis prepares bone ends with concave and convex reamers designed for hip surgery, followed by fixation with a long intramedullary rod. (D, E) AP and lateral radiographs of a resection arthroplasty as the first stage of an intended 2-stage reimplantation protocol for an infected TKA. A second nonarticulating antibiotic impregnated methacrylate spacer block has been placed between the ends of the femur and tibia as the first displaced. The spacer has been prevented from dislocating by 3 Steinman pins that extend from the femoral canal to the tibial canal, crossing the knee joint. While they are inside the cement at the joint, the bare metal ends extend into the medullary canals. The distal end of a locking nail for femoral fracture fixation is apparent in this radiograph. (F, G) AP and lateral radiographs taken soon after removal of an infected TKA. A nonarticulating antibiotic impregnated cement spacer block is in place, but later dislocated. The distal end of a locking rod with screws is in position for a more proximal femur fracture. (H, I) AP and lateral radiographs of a subtrochanteric femur fracture ipsilateral to the primary TKA. This was treated with the anterograde locking nail apparent in (D-G). Some months previously this TKA had been treated for infection with arthrotomy, debridement, and poly exchange. Quite conceivably, the TKA was infected at the time this rod was inserted. As it was never removed, and as the medullary canal has frequently bee the source of culture positive material when infected arthroplasties are removed, infection could have persisted on a biofilm over the rod, subverting the intention of a 2-stage protocol. (J, K) AP and lateral radiograph of a primary, cemented, cruciate retaining TKA. Note calcific arterial disease. This TKA was complicated by deep sepsis, necessitating an arthrotomy and debridement more than 4 weeks after surgery. Tibial and femoral components were left in place. (L) Lateral radiograph after primary TKA. Dots outline part of the cement mantle. (M) Lateral intraoperative image intensifier view of resection after placement of the long IM nail for arthrodesis. Arthrodesis was selected when cultures remained positive after resection arthroplasty and a second debridement. Biofilm is elaborated on foreign material, where bacteria may reside unmolested by host leukocytes and parenteral antibiotics.

206 ity. Does this infection, in your mind, extend more proximally? ROSENBERG: It’s very worrisome, and I think there’s evidence that infections about the knee are frequently associated with infection in the intramedullary canals. MODERATOR: Right. ROSENBERG: You have to be very cautious about that IM rod. MODERATOR: I find my trauma colleagues are much more aggressive and cavalier about fixation in the presence of infection these days than anyone was 20 years ago. When the paths of arthroplasty and trauma surgeons converge in the care of an individual patient, I find the two groups have different orientations. Foreign material scares me in terms of infection and arthroplasty. I do not want that rod in what I think is an infected canal. DODD: I think that’s an excellent point that you cannot stress enough, because the needs of the fixation surgeon, the fracture surgeon, are definitely different from ours. Their primary goal is to get the thing to heal and then worry about infection. MODERATOR: Well, they also have the option somewhere down the road of taking the hardware out if it heals. DODD: Yes, absolutely. MODERATOR: I think we see that different orientation in this case. Given that skin staples from the locking rod and staples from the arthrotomy are present at the same time indicates that the treating surgeon was willing to leave hardware in an infected environment all the while that a 2-stage protocol was underway to try to eradicate infection so that a TKA could be reimplanted. As we go further back in time, we see that the patient suffered a subtrochanteric fracture above his primary TKA (Fig. 6H and I). At the time the fracture was treated, surgeons noted knee swelling. Within a couple of weeks after the nailing, the TKA was clearly infected, and the resection arthroplasty was performed, with the IM rod still in the canal above. Chris, how would you have treated this subtrochanteric fracture, with a TKA below it? Would it be part of your history taking to ensure that the TKA is not infected? DODD: Yeah. You’ve got to do that straight from the go. MODERATOR: So would you necessarily aspirate that knee before you put a rod up? DODD: Yeah. Yeah. MODERATOR: OK. Bernie? STULBERG: If there was no real reason for it to be infected, I might not investigate the knee. MODERATOR: More information for you then. Earlier in this patient’s history, the TKA was infected 6 months post arthroplasty but before the subtrochanteric fracture. A debridement and poly exchange was done followed by 6 weeks of antibiotics. Aaron, how does this shape up as treatment for a TKA, infected at 6 months post-op? ROSENBERG: I’m waiting to see that in 2007 this poor patient sold his soul to the devil! I’m sorry, what was the question? MODERATOR: How does this shape up— 6 months after TKA, the infection is diagnosed, and it’s treated with a de-

K.G. Vince bridement, a polyethylene exchange, and an extended course of antibiotic therapy. ROSENBERG: It could have been an acute infection. If a total knee was doing perfectly well for 4 and a half months and the patient went to the dentist, and the next day the patient had a painful swollen knee, I might treat that with a polyethylene exchange. MODERATOR: But are we being clear here about what this is most likely to be? In the absence of a history like the dental problem, most surgeons and certainly every patient is tempted to have a debridement rather than a resection irrespective of when— ROSENBERG: Oh, absolutely. MODERATOR: The infection comes on. BOURNE: If you have a patient who for 6 months has done poorly and has had persistent swelling and now presents with drainage at 6 months, that patient is not a candidate for a poly exchange. Very few patients are candidates for a poly exchange at 6 months, unless there’s a very, very, very specific history of a wonderful result, and in the past 2 to 3 days some inciting episode of sepsis. MODERATOR: Can we go down the panel starting with Chris? Any reason to try debridement with poly exchange at 6 months post TKA? Or, should we be strict about our definitions of chronic infections and take it out? DODD: You need to take it out. MODERATOR: Bernie? STULBERG: Yeah take it out, although you haven’t told us the whole story yet. MODERATOR: Believe me, it’s the end of the story. BOURNE: At 6 months, without the history of initial success and a dramatic change linked to a suspicious event, you take it out. MODERATOR: All agreed, at 6 months postop, the infected TKA must come out, usually as part of a 2-stage reimplantation protocol. STULBERG: It is retained cement and leaving it is not defensible. MODERATOR: What do you do to ensure that you have all the cement out when you do a resection? Chris, how do you know you got it all? DODD: I take an intraoperative x-ray. MODERATOR: OK. Anybody else? HOFMANN: Fluoro. MODERATOR: I think intraoperative x-rays or fluoro are wonderful ideas. They are a great record of what’s left of the bone before a spacer obscures the view, so you can plan the revision. It’s also a legal document that says you did take everything out. This case reminds us of basic principles of the importance of removing all foreign material. It also illustrates that the orientation of trauma surgeons and arthroplasty surgeons about hardware in the presence of infection differs. While leaving hardware until union occurs may be the best strategy in fracture care, it may preclude success for the 2-stage reimplantation protocol.

Case challenges: what would you do?

207

Figure 7 Case 3. (A) This case, of a 73-year-old man with multiple revision arthroplasties, ended in above-knee amputation due to ineradicable infection. (B) Intraoperative photo during resection of an infected third revision with such extensive bone loss that an external fixator was necessary to stabilize the limb. Amputation was recommended, but at this stage the patient declined. (C) AP radiograph of a third revision TKA with proximal tibial allograft reconstruction. Dots indicate initial position of allograft that has subsided. Cerclage wires and strut allograft in the proximal femur were required for an undisplaced, intraoperative femur fracture when the 240-mm stem extension was implanted with the femoral component. (D, E) AP and lateral radiograph of penultimate reconstruction. This took the form of revision of the tibial component only for aseptic loosening. By not revising the femoral component, the surgeon was not able to control alignment (varus in this radiograph) or gap balance. In addition the existing femoral component did not provide the option of constraint. (F) The left side shows an AP radiograph of loose tibial component in a revision arthroplasty. The right side shows the re-revision with solid, fully cemented fixation of the tibial component, an inordinately thick tibial polyethylene insert, and unsustainable tibial bone loss. Partial revision generally yields worse results than full-revision TKA.

Case 3 MODERATOR: The next case ended in amputation (Fig. 7A). ROSENBERG: This is a little depressing. DODD: I thought they were getting easier. MODERATOR: No not all. This elderly gentleman initially wouldn’t accept amputation, so an external fixator was placed temporarily across a multiply operated knee with a resection arthroplasty, intractable infection, and profound bone loss (Fig. 7B). HOFMANN: I can see why you left LA. I’m depressed already. MODERATOR: We are looking at the result of a third revision as yet uninfected. The proximal tibial allograft, which was combined with its extensor mechanism,12 has subsided (Fig. 7C). How do the panel members manage this magnitude of missing proximal tibial bone at revision? Bernie? STULBERG: I’m not a big fan of trying to get a TKA that works across huge gaps. You could use metal augmentation if

the bone bed was really free of infection, or fuse the knee with a long IM rod and allograft bone.13 MODERATOR: Intercalary allograft? STULBERG: Intercalary allograft and a long rod. MODERATOR: All right. Chris? DODD: The alternative is a tumor prosthesis to excise the proximal tibia there. MODERATOR: The problem is, there’s terribly deficient proximal tibial bone. Aaron, you have some experience with tumor prosthesis. What’s your take on this? ROSENBERG: You have to ask yourself several questions before you proceed with the reconstruction. The first and the biggest hurdle is how much surgery is this patient going to be able to tolerate? The second is, what do I do when this fails? Do I have an option to bail out on? And then you have to ask yourself the questions, do I have an extensor mechanism that works, or can I put one in place safely? Do I have something to attach a prosthesis or allograft to? And probably most important, is the bed clean? There’s

208 probably no good reason to use allograft—a big bulk allograft in the distal femur as opposed to a tumor implant. Tibial allograft is useful if you need an extensor mechanism because the reconstructions with just the tumor prosthesis are not particularly good in terms of active extension. Allograft extensor mechanisms work better. MODERATOR: This was the previous revision done elsewhere (Fig. 7D and E). It was a partial revision to treat a loose tibial component. The revision looked remarkably like the situation that preceded it that, in fact, had loosened as well (Fig. 7F). We still see constructs like this done today. Because implant companies provide a wide interchangability between tibial sizes and femoral sizes, a surgeon can actually put in quite a small tibial component with a much larger femur. Chris, what’s your comment on the type of reconstruction that was done before the final reconstruction? DODD: I think the problem has more to do with the length of the tibial stem. It just doesn’t seem long enough from the word go. I’m not so worried about the mismatch between the femur and the tibia. MODERATOR: How would you choose the tibial stem extension then? DODD: I would look how far down the tibia it loosened. MODERATOR: So you would have selected a tibial stem that bypassed the position of the preceding stem? DODD: Exactly. MODERATOR: OK. Bernie, what would be your approach to this knee right now if you had to fix it? I used a proximal tibial allograft and got into trouble with infection. STULBERG: The challenge here is difficult because you can keep spreading the problem. The devices used aren’t the right ones for the kinds of issues you’ve got. I would consider using a proximal tibial tumor implant here because you’re way below the fibular head and you need constraint. And so I don’t think you can keep pushing this one out to the envelope. I’d probably use something that I could consider stable and maybe you can get lucky with enough fixation distally in the tibia longer. MODERATOR: Here is the construct that the patient showed up at our institution with. Aaron Hofmann? HOFMANN: Yeah. I think it really depends on—I didn’t understand whether the patient has an extensor mechanism, though. MODERATOR: The patient doesn’t have an extensor mechanism. HOFMANN: If the patient had some extensor mechanism, I’ll tackle it. Otherwise, I’m looking at fusion. I’m not very successful more than a year out with extensor mechanism allografts. I can put them in, and they blow apart, so I’ve given up on allograft, extensor mechanism. I just offer the patient a fusion. MODERATOR: Really? So you’ve given up on allograft extensor mechanisms? Aaron Rosenberg, your group seems to have learned the hard way how to do them right. ROSENBERG: There was a time when I was ready to give up, but most of these are looking pretty good now at 7 or 8 years postop. You must put them in tight.14 They gradually loosen to the point where they have good motion. I have seen

K.G. Vince fractures of the patella at 8 or 9 years out in big, heavy-set patients. If you think of this as a tumor situation, there are patients who need resection of the proximal tibia, including this much bone, and who get proximal tibial replacements or allograft replacements. It’s possible to do it. You have to add up all the factors involved: age, the degree of infection if there’s an infection, whether you’ve cleared the infection, the quality of the soft-tissue envelope, and then is the patient willing to live with protection, such as a hinged knee brace in perpetuity? MODERATOR: Bob Bourne, the role of extensor allografts? BOURNE: I think we’ve learned a lot from Aaron, actually, in terms of putting them in tight. Also, don’t be in a hurry to get them going. We use the tendo-Achilles more than we do the extensor mechanism allograft.15 I’m not sure it makes a big difference. We hold the knee right out straight for the first month, then we allow 45 degrees and then we progress to 45 or 90 degrees of flexion. We’re very slow on getting them going. I’ve been fairly happy with them. MODERATOR: I certainly find the patients are very happy with extensor allografts compared to any alternative. Chris, what is your take on extensor mechanism allografting? DODD: I have no experience with them. MODERATOR: OK. Bernie? STULBERG: I like them. I think they work. MODERATOR: OK. Fair enough. Let’s get back to our patient. This was the partial revision that had been done: revision only of the loose tibial component (Fig. 8). You see the 1 on the right. Chris, I think you made the point that you would go much further distally for tibial fixation. I personally think it’s more important to build bone back up and try to get more anatomic dimensions. Aaron, what’s your thought about whether it is wise to just revise a single loose component and as in this case to leave the femoral component in place? Should the surgeons have done something else? ROSENBERG: You should revise everything almost every time. There are very rare exceptions to that rule. MODERATOR: Agreed. Bob Bourne, what is your take on single-component revision vs complete revision? BOURNE: I can’t remember the last time I did a singlecomponent revision. I just find there’s usually all sorts of issues. The implant may be scratched; your exposure may be difficult, or you just can’t do a good job. So I think you’re much better to take everything out for each revision. MODERATOR: Aaron, what is your perspective on singlecomponent revision? HOFMANN: I think it’s rare, because I look at this kind of case and wonder what if I need more constraint? I cannot introduce constraint without revising the femoral component as well? Or maybe you need to convert the arthroplasty to a hinge. When your revision is constrained by the size of the component you are leaving, it’s not a pretty situation. MODERATOR: Exposure is not a problem in this case because of instability. In other revisions, leaving the femoral component in place makes the exposure difficult. It is the femur that controls the soft tissues for us in terms of flexion

Case challenges: what would you do?

Figure 8 Case 4. This is a conventional chronologic presentation of a failed TKA, to test if our panel would approach the clinical problem with the lessons of the first 3 cases in mind, noting perhaps that this case has the potential of a similarly tragic outcome. (A, B) AP and lateral radiograph of dramatic aseptic failure of a primary TKA with indisputable and extensive tibial bone loss, which is nonetheless invariably greater than appreciated on simple radiographs. (C, D) AP and lateral radiographs of a first revision TKA. The essential elements are valgus alignment to decrease load on the medial compartment, achieved by reaming the femoral canal preferentially to the lateral side, installing a diaphyseal engaging uncemented stem in valgus, and then centralizing the component distally with an offset stem. Structural allograft has been necessary for this degree of bone loss in the past, but has largely been supplanted by the use of modular porous metal to restore bone and augment fixation, as seen here in the proximal tibia.

extension gaps—whatever we do to the tibia has an equal effect in flexion and extension. Bernie, when might you consider a single-component knee revision? STULBERG: I’ve had about 4, all in a specific design of knee where the tibia was in a little varus and it subsided in

209 heavy patients. That’s the only time I’ve ever done singlecomponent revisions. In this case, for example, there wasn’t ligamentous stability and so a full revision would have been better. MODERATOR: Chris, what is the role of single-component revisions? DODD: Can’t remember the last time I did one. MODERATOR: There is consensus among our panelists that we rarely perform single-component revisions. I’ve been on the receiving end not only of failed primaries but many failed revisions. These were often single-component revisions, performed because the surgeon was trying to be kind or conservative. The literature supports full revisions in the vast majority of cases.16-18 The other study that I’ve been hoping to see in the literature, but which still hasn’t appeared, is the treatment of infected revision TKA. There is partial information, such as this series from Bristol on infected TKA, that included 4 infected revisions. The results were above knee amputation, chronic draining sinus, and 2 arthrodesis.19 We glibly throw infected revision TKA into the same category with infected primary knee replacements, but the differences are profoundly different. Aaron, what’s your prognosis for the infected revision arthroplasty? Rosenberg: I think the prognosis is grim. But again, it depends on all the factors I mentioned before. I explain these factors to every patient, because many believe unrealistically that we can always save the knee and save the leg. Despite that, I have several patients who were stubborn and insistent, and after 7 debridements and a reimplant and an allograft, they got a knee that worked. Was it worth it economically or time-wise to that individual? Maybe, but you have to lay down the law about the risks. MODERATOR: When the patient looks at their leg after multiple surgeries and a resection, they see what looks like a leg on the outside. We look inside though and see nothing to work with. Bob? BOURNE: We looked briefly at our infected revisions, and there were 2 prongs to this. We had a 25% failure rate with 2-stage exchanges, and then if you looked at the functional outcome, it was terrible compared to our usual revisions. And it’s not surprising after all you put these people through. Infection is a big, big, complication of a revision TKA. MODERATOR: Aaron, should we change our thinking radically? If we have an infected revision, should we be counseling this patient in a very different way? Should we recommend arthrodesis? HOFMANN: Considering failed treatment of the infected primary, where the reimplant is infected, you want to ensure that the person’s first time infection was treated appropriately. Maybe a bug that was never cultured from the primary has shown up in the revision. The infected revision was typically a culture-negative case. In 15% of cases there will be 3 bugs but only has grown on culture. You want to ensure the medullary canal was cultured and that you’re not missing something. You want to confirm that the patient had appro-

K.G. Vince

210 priate antibiotics for the appropriate length of time and the appropriate spacer, and that everything was done right. And I’ve certainly had those two-time losers in my own practice. Often it’s just a bad host. The patient may come back with a different bug than they had originally. Sometimes you just can’t solve the problem that you’re dealing with or see. MODERATOR: You are describing the situation of a failed 2-stage reimplantation protocol. The Mayo Clinic data on patients undergoing a second 2-stage reimplantation protocol are discouraging— only 1 in 20 cases with a good functioning arthroplasty, without chronic suppressive antibiotic therapy. There were 10 fusions, 4 amputations, and 4 permanent resection arthroplasties.20 We don’t know if the results of a first 2-stage protocol for an infected revision is much better. Should we have a different approach to patients who are infected after any kind of revision arthroplasty? STULBERG: You’re talking infections here, about differences in bacteria, about problems with the soft-tissue bed and the bony bed. We reported ours a long time ago,21,22 and we also had about 20-25% failure rate. MODERATOR: Chris, I haven’t heard strict criteria from the panelists about when we should say to a patient that a 2-stage protocol is not appropriate. Should we approach the infected revision differently than we do the infected primary? DODD: Yes, although I do take Aaron Hofmann’s point. In the UK we have a number of centers that are treating infection somewhat less than ideally. And so if you go back and evaluate the way the infection was dealt with the first time around, you can fairly quickly tell whether it’s been done appropriately or not. And if it’s a nasty bug and it’s been treated appropriately, then there is probably nothing else we should do. MODERATOR: If I understand correctly, you would say that if an otherwise healthy host had not received optimal treatment in a first 2-stage protocol, you would consider a second. Otherwise it should be avoided, presumably with recommendation of a fusion, permanent resection arthroplasty, or amputation, those being the only alternatives. I have shown extreme cases today and your answers may have been influenced realistically by seeing the dismal failures at the outset. In the first case, the honored principle of removing all foreign material in anticipation of a reimplant may ultimately not have been applicable, given the risk to the patient. Perhaps in that case, recognition of an earlier point in the patient’s care where an extremely aggressive approach, such as a total femoral replacement, might have been a better strategy BEFORE infection set in. In the persistently infected TKA treated with arthrodesis after 2 failed resections, by contrast, we saw a multiply operated case where perhaps detailed attention to fundamentals such as removing all foreign material, including the IM rod adjacent to an infected arthroplasty, might have yielded success. In one case basic principles failed to solve the problem and in the other basic principles were not followed. Bob, yes please, go ahead. BOURNE: I think to really get a handle on this, we’re going to have to take many big centers and combine their data,

because none of us have enough data to come out with really good guidelines. And I hope we will do that. But what we all try to do is to take the typical infected primary and take basic principles and apply them to a very difficult revision. Maybe we should be waiting a lot longer before reimplanting these cases. The only way we’re ever going to get a handle is to have some type of infection registry with many centers. MODERATOR: Excellent point. When I started doing revisions, I made friends with a plastic surgeon, for those times when I needed flaps. I think if I were doing general orthopedics, I would make friends with somebody who did many complex arthroplasties that I could count on to help me with these difficult cases.

Case 4 MODERATOR: And now a little more straightforward case here. This is a loose prosthesis (Fig. 8A and B). Aaron, how would you deal with that bone defect? HOFMANN: I’d probably use a tibial augment and a cementless stemmed tibial component. MODERATOR: What kind of augment? HOFMANN: I’d probably use a block-type augment on the medial side. I’d freshen up the lateral side a little bit and I’d revise both components. MODERATOR: Bob, any other different approaches? BOURNE: No. Obviously you presented so many terrible cases today that it reinforces the message to ensure it’s not infected. MODERATOR: This is a clear case of aseptic loosening with considerable medial tibial bone loss. BOURNE: My plan “A” would be 1 of the many very good revision systems on the market with some type of metal augment. I think they come in many different shapes. I like the block augment that Aaron talks about. And you get into debates as to whether you cement the stem or use a hybrid fixation like John Insall popularized.23,24 MODERATOR: Bernie, how would you deal with this defect? STULBERG: Nothing different from what has been said, but this would be a case I wouldn’t hesitate to get an intraoperative X-ray when I’m redoing it just to ensure I line it up right. MODERATOR: Chris, how would you deal with this defect? This is a first time around revision and an opportunity to ensure this case doesn’t end up like the others. DODD: No different from the faculty apart from I tend to cement the stems. HOFMANN: This is not a 1-component revision. The femur is oversized and overhanging. MODERATOR: Yes, and loose. Anyway, this is 1 where I used the trabecular metal cones that have gone a long way to helping us out with bone loss. There is a small piece of bone autograft I placed on the medial side, with an uncemented long stem device (Fig. 8C and D). I think we have new technology that may keep some of these bad cases on track and not allow them turn into the disasters I have shown you today.

Case challenges: what would you do? Gentlemen, I thank you for allowing me to get these cases out of my system. Some were mine and some I consulted on, but they have all weighed heavily on my shoulders. It was very cathartic, very somber, and I’m buying rounds tonight! ROSENBERG: It’s called a lifetime’s worth of disasters in half an hour! MODERATOR COMMENT: I am surprised in the final case, that none of our faculty noted that the degree of bone loss in this case will be greater at surgery than it appears on radiographs. Indeed, this amount of medial tibial destruction resembles the degree of bone loss on the previous patient who went on to suffer amputation after conventional solution, such as block augments and tibial stems. This is precisely the kind of case that will fail from repeat aseptic loosening unless a valgus mechanical axis25 is created and either proximal tibial allograft reconstruction or porous metals are used.

References 1. Cierny G 3rd, DiPasquale D: Periprosthetic total joint infections: Staging, treatment, and outcomes. Clin Orthop Relat Res 403:23-28, 2002 2. Sherman SL, Cunneen KP, Walcott-Sapp S, et al: Custom total femur spacer and second-stage total femur arthroplasty as a novel approach to infection and periprosthetic fracture. J Arthroplasty 23(5):781-786, 2008 3. Salvati EA, González Della Valle A, Masri BA, et al: The infected total hip arthroplasty. Instr Course Lect 52:223-245, 2003 4. Peters CL, Hickman JM, Erickson J, et al: Intramedullary total femoral replacement for salvage of the compromised femur associated with hip and knee arthroplasty. J Arthroplasty 21(1):53-58, 2006 5. Streubel PN, Gardner MJ, Morshed S, et al: Are extreme distal periprosthetic supracondylar fractures of the femur too distal to fix using a lateral locked plate? J Bone Joint Surg Br 92(4):527-534, 2010 6. Bong MR, Egol KA, Koval KJ, et al: Comparison of the LISS and a retrograde-inserted supracondylar intramedullary nail for fixation of a periprosthetic distal femur fracture proximal to a total knee arthroplasty. J Arthroplasty 17(7):876-881, 2002 7. Gliatis J, Megas P, Panagiotopoulos E, et al: Midterm results of treatment with a retrograde nail for supracondylar periprosthetic fractures of the femur following total knee arthroplasty. J Orthop Trauma 19(3): 164-170, 2005 8. Rolston LR, Christ DJ, Halpern A, et al: Treatment of supracondylar fractures of the femur proximal to a total knee arthroplasty. A report of four cases. J Bone Joint Surg Am 77(6):924-931, 1995

211 9. Gujarathi N, Putti AB, Abboud RJ, et al: Risk of periprosthetic fracture after anterior femoral notching. Acta Orthop 80(5):553-556, 2009 10. Zalzal P, Backstein D, Gross AE, et al: Notching of the anterior femoral cortex during total knee arthroplasty characteristics that increase local stresses. J Arthroplasty 21(5):737-743, 2006 11. Bargiotas K, Wohlrab D, Sewecke JJ, et al: Arthrodesis of the knee with a long intramedullary nail following the failure of a total knee arthroplasty as the result of infection. Surgical technique. J Bone Joint Surg Am 89(suppl 2):103-110, 2007 12. Barrack RL, Lyons T: Proximal tibia—Extensor mechanism composite allograft for revision TKA with chronic patellar tendon rupture. Acta Orthop Scand 71(4):419-421, 2000 13. Benevenia J, Makley JT, Locke M, et al: Resection arthrodesis of the knee for tumor: Large intercalary allograft and long intramedullary nail technique. Semin Arthroplasty 5(2):76-84, 1994 14. Burnett RS, Berger RA, Paprosky WG, et al: Extensor mechanism allograft reconstruction after total knee arthroplasty. A comparison of two techniques. J Bone Joint Surg Am 86(12):2694-2699, 2004 15. Bermudez CA, Ziran BH, Barrette-Grischow MK: Use of Achilles tendon-bone allograft for reconstruction of the patellar tendon in patients with severe disruption of the extensor mechanism of the knee: A case report. J Trauma 63(1):211-216, 2007 16. Fehring TK, Odum S, Griffin WL, et al: Outcome comparison of partial and full component revision TKA. Clin Orthop Relat Res 440:131-134, 2005 17. Knutson K, Lewold S, Robertsson O, et al: The Swedish knee arthroplasty register. A nation-wide study of 30,003 knees 1976-1992. Acta Orthop Scand 65(4):375-386, 1994 18. Mackay DC, Siddique MS: The results of revision knee arthroplasty with and without retention of secure cemented femoral components. J Bone Joint Surg Br 85(4):517-520, 2003 19. Blom AW, Brown J, Taylor AH, et al: Infection after total knee arthroplasty. J Bone Joint Surg Br 86(5):688-691, 2004 20. Hanssen AD, Trousdale RT, Osmon DR: Patient outcome with reinfection following reimplantation for the infected total knee arthroplasty. Clin Orthop Relat Res 321:55-67, 1995 21. Wilde AH: Management of infected knee and hip prostheses. Curr Opin Rheumatol 6(2):172-176, 1994 22. Wilde AH, Ruth JT: Two-stage reimplantation in infected total knee arthroplasty. Clin Orthop Relat Res 236:23-35, 1988 23. Haas SB, Insall JN, Montgomery W, 3rd, et al: Revision total knee arthroplasty with use of modular components with stems inserted without cement. J Bone Joint Surg Am 77(11):1700-1707, 1995 24. Vince KG, Long W: Revision knee arthroplasty. The limits of press fit medullary fixation. Clin Orthop Relat Res 317:172-177, 1995 25. Vince K, Bedard M: Implanting the Revision total knee arthroplasty, in Lotke PA, Lonner J (eds): Master Techniques in Orthopedic Surgery. Baltimore, Lippincott, Williams and Wilkins, 2008, pp 203-228