Case: Gunshot Wound and TKR
Reported by Myles Clough, Orthopaedic Surgeon, Kamloops, BC, Canada
I saw a 47 year old man yesterday, referred from a remote area of northern BC. He had booked a ticket out on the same day and was unable to stay for any more extensive work-up. He had forgotten to bring his Xrays.
In 1991 he was shot in the knee with a .303. Consideration was given then to amputation but instead he had debridement and skin grafting. There is a question of infection with enterococcus showing up in the culture reports but this may have been superficial. He was left with a stiff, short, unstable left knee. He was offered knee fusion in another secondary referral centre and booked twice but failed to show up for the surgery. He has not tolerated a brace. He doesn't communicate well.
Examination showed the leg to be 3 cms short. There is deficiency of the medial femoral condyle and loss of the medial collateral ligament. However, on palpation there is some bone medially. On weight bearing his knee goes into 20 degree varus. He has 40 degrees flexion. His foot is intact with normal neurovascualr status. He has a severe untreated problem with his right hand and has been recommended by yet another orthopaedic surgeon to have a proximal row carpectomy.
I obtained the Xrays below and have asked his home community to get plain tomos and a CT scan. The CT is what I need but I think the artifact from the shrapnel may degrade the study. I want to know how much bone stock he has medially. Am I crazy to think of total knee replacement (TKR) in this man?
I realize he is unreliable but he really doesn't want a stiff knee and I think of a knee fusion as technically more difficult and certainly rarer than a TKR. I am thinking of a custom femoral component building up the medial side +/- constraints. He has semitendinosis, sartorius and gracilis so I was thinking I could accomplish some form of medial reconstruction. If it failed we would revert to a fusion. According to his previous surgeons he accepted the possibility of AK amputation if fusion failed when they discussed surgery earlier. However, this was the surgery he failed to turn up for! I am going to ask his GP why he doesn't use a brace.
1. How badly would an attempt to do a TKR compromise a subsequent attempt to fuse?
2. If TKR what technical tips does anyone have?
3. If fusion what technique would you use?
The plain films show major deficiency of the medial femoral condyle and healing of the lateral femoral condyle in lateral displacement, shortening and possibly mal-rotation. There is some degenerative joint disease. The CT is what I need but I think the artefact from the shrapnel may degrade the study. I want to know how much bone stock he has medially.
Xray of the knee pre-operatively
AP and lateral tomograms were obtained nearer his home and sent for evaluation. They show the deficiency of the medial condyle in better detail. Most of the bone to be seen medial to the midline on AP xray is patella. Also evident on the AP tomogram is the degree of lateral offset of the lateral femoral condyle. CT scan was also performed and the degradation from the artefact was not a problem. This study allows us to see the extent of the medial deficiency.
AP tomogram of the knee
Lateral tomogram of the knee
CT scan of the knee
The problems identified in the overall management of this case are as follows:
- The patient subsists partly by hunting and is adamant that a knee fusion should not be done.
- Evidence to suggest he will not be a co-operative patient
- Unable to tolerate current symptoms or use a brace
- Possibility of remote infection
- If a knee replacement were to be undertaken it would require attention to the following:
- Medial femoral condyle deficiency
- Offset of femoral shaft from the centre of the knee
- Uncertain rotation of lateral condyle
- Combination of primary TKR for the lateral condyle, tibia and patella and "revision" for the medial side.
- Option to fall back to a fusion if the operation proved impossible
- Inexperience of the surgeon and operating team
- The patient and his family have been told that any surgery carries the risk that it might fail and necessitate a fusion or even an amputation.
- He consented to undergo a fusion of the knee if, at the time of surgery, we considered it inadvisable to proceed with the TKR
- The total knee system chosen was the Zimmer LCCK (Legacy Constrained Condylar Knee) which is a revision system which is stemmed for increased stability and may be completely constrained if the knee is unstable.
- He consented for autologous bone graft from the iliac crest and allograft bone was also available.
- Two experienced orthopaedic surgeons formed the operating team and the sales representative was asked to attend to help the staff with the unfamiliar instruments.
- Manuals for the LCCK instruments were distributed to everyone.
- The Neff femoro-tibial nail system was available if we had to revert to a fusion after the shafts of the tibia and femur were reamed.
- Blood products were available. Our hospital does not have a cell saver yet.
Under anaesthetic we noted that there was good medial constraint. We couldn't tell whether this was surviving MCL or simply scar tissue. We were careful not to dissect round to the posteromedial corner and disturb this.
A paramedial incision was made and the patella dislocated laterally in the normal way. The front of the knee was all scarred down and the patella tendon insertion stripped partly off the tubercle when we flexed him up. We could obtain 100 degrees of flexion but he still had a 15 degree flexion deformity. There was no evidence of infection.
Once the soft tissues were all released we could see the extent of the medial deficiency. This also illustrates a major problem. The distal cut was made with reference to the intramedullary guide. But we had nothing to reference off for the rotation of the "primary" anterior and posterior cuts of the lateral femoral condyle.
Extent of medial insufficiency
Sizing of the femoral component was also difficult because the femoral shaft is not in the normal position relative to the femoral condyles; we measured and then used one size larger. I think it might have been better to go 2 up as our component was still quite narrow.
After we had made distal and posterior cuts on the femoral condyle we made the tibial cut and then used blocks to check stability in flexion and extension. This was adjusted until we had good balance - lateral condyle only of course.
We then had to cope with the offset. The component only allows 1/2 cm offset and this wasn't really enough. However, we did have good support for the lateral portion of the femoral component. By the time we had trimmed and adjusted, the femoral component was quite far proximal. We thought this would be a concern, but it never was as the knee was always tight in extension and we could never get it fully straight. What it did mean is that the medial femoral remnant was now just "within reach" By the time we had added the 1 cm distal and posterior blocks to the medial side we actually had contact with medial bone.
The finishing element is a "box" cut in the trochlea to afford rotational stability. The femoral endcuts at the end of this process are shown. The patellar surface was prepared and the final trials were done before cementing. The final appearance doesn't look very different from a normal knee replacement but note the distal and posterior augments.
Knee prosthesis in place
The tourniquet was up for 120 minutes then down for about 40 minutes and then up again for about 20 minutes while we were cementing. The patient has lost about 2 litres into the drains overnight but Haemoglobin is holding at 97.
Post procedure AP and lateral X-rays show the components to be well aligned and the IM stems are fitting snugly. The lateral shows the size of the medial augments. He still has a 10 degree flexion deformity which didn't seem to be affected by changing the size of the tibial plate. I think he had contracted scar tissue posteriorly and didn't want to mess with it. We repaired the patellar tendon attachment and will keep his knee straight for a while.
Postoperative AP Xray of the knee
Postoperative lateral Xray of the knee
Of course, the result isn't known on the first day post operation but I thought the case was challenging enough to be interesting and I will certainly update you on his progress.
Thanks to Dr. Jim Poulsen (Assistant), Linda Barrie and Koos Meijerhoff (scrub nurses) for their expertise. David Lukinuk, (Zimmer Representative), provided invaluable help in the preparation and during the case.
FROM: Ma Zhen-sheng, MD
I think ultrasonic examination, and blood vessel radiography should be taken into account to show the route of the main blood vessel around the knee before you perform total knee replacement. If there is no potential infection, and the blood vessel is ok, you can do total knee replacement.
The bone defects in the medial condyle is not difficult to deal with, because in the process of the knee replacement, you will cut away some the bone mass at the ends of the femur and tibia, and you can use allograft. We have done a AGC total knee replacement two years ago and the patient recovered with satisfactory function of the knee. The patient is a 53 years old male with fibro-sarcoma and was curretted and auto bone graft in 1979, segmental femoral allograft with joint surface transplantation in 1990. Unfortunately, the x-rays after knee replacement are not in my hand, and I cannot present them here.
As for knee fusion, in my experience, it is much easier than total knee replacement. The cost to have a TKR is much more expensive than fusion in China. For the fusion, there are several ways to do it, but the simplest one is to cut the joint surface of the tibia and femur as you do TKR, to oppose the two segments together, the patella is inserted in the groove cut in the middle line of the two segments to bridge the two. Two cross strong K wire are used to fix the two together, after closing the surture and dressing, we use plaster cast for three month to make the knee fused.
As for the fragments of the bullet in the case, just let them stay there for life. What we should do is to improve the function of the knee or the quality of the patient's life, not the bullet.
With best regards!
Ma Zhen-sheng, MD
Department of Orthopedics, Xijing Hospital
15th Changle West Road, Xi'an 710032, China
FROM: Dr. Derek Cooke
On the PO AP, it seems the femoral IM stem is linked in some valgus? Is that a function of the IM stem configuration...i.e. off-set, used to position the femur component more laterally? If this was a part of your pre-op plan what about a custom stem link with even more 'offset'? I mention this because I had needed to get 2 stems customized for a patient with a re-revision infected failed TKR. One of the options was a modular link between stem to femoral component.
Why long stem for the tibia?
Comments are to consider a an intraoperative femoral osteotomy to correct the valgus and offset (OK I said consider..not sure how I would do it). Or, a tumor type implant resecting the distal femur (not my choice and I think still an option as back up here). In these knees I get my exposure either by a Quads snip or by way of a long tibial tubercle osteotomy (Whiteside like, but not so extensive in my hands).
FROM: Dr. Kleuber
Hope his ligaments were all intact, when you implanted this prostheses. Otherwise have got experience with 100s of revision cases, that semiconstrained knees will work well just a few months, then instability occurs. Moreover in cases as such you presented.
Moreover you did not correct the legs angle (bad fracture healing) so that you used a prosthesis which may suffer material failure after some time.
If we want to convince other doctors about long-stemmed prostheses, we have to tell them, that they work well with a hinge, if ligaments are unstable. Such hinge total knees have a survival of 95% after 15 yrs. This is really not bad, isn’t it. Maybe they cost a little more... but it’s for the patient, not for hospital’s sake.
Dr. Klueber, ENDO-Klinik/Hamburg
FROM: Dave Hubbard
Congratulations,,,,,, looks like you really can "make a silk purse out of a sow's ear". I look forward to hearing how he is doing on follow-up. You mentioned the post op blood loss of 2 L in the drains, did you utilize a reinfusion drain for postoperative blood salvage? Thanks for posting the details as a web page, makes for a fantastic presentation. I hope others will follow your lead in presenting unusual cases in this manner.
Dave Hubbard, RN, Dallas, TX
FROM: Rene Hartel
Hope you had a quiet evening after your day in the hospital. Bravo! This is what makes the Inet and mailbase worthwhile!
I always wonder what colleagues do after such a strenuous exercise. Take a nap? Have a beer? Watch a movie?
Seriously, impressed and congratulations.
Rene Hartel, Orthopaedic Surgeon
CH Argentan, France
FROM: Miles Clough (originator)
Thank you for the comments.
Femoral osteotomy: We did discuss doing this during the case. It would have increased the complexity of the operation, the length and blood loss and the risks of failure. The time to have done this would have been at the original injury when it was clear that you were going to salvage the knee. If an osteotomy was essential I think it might be done as a separate operation 6 months ahead.
Valgus angulation: I haven't measured on the Xray but the angulation cannot be much more than 6 degrees which is the set angulation determined by the distal cut. If it is more than that, it is likely because of the stem tilting the articular component as we were cementing. It looks more dramatic because of the lateral offset. You don't see the alignment of the component "straightening out" again behind the anterior articular surface, but if you look carefully the sides of the femoral condyles are not parallel to the stem just above the articular surfaces.
Custom component: I think this might have been a good idea. I thought that the reconstructions from the CT scans would not be good enough to allow us to take the measurements needed for creating a custom component but they probably were OK.
Long stemmed tibial component: This was selected pre-op because I thought we would need a constrained coupling. When it became clear that we could have a stable situation with a posterior stabilized tibial surface I did discuss using a standard stemmed tibial component. I think the decision was made partly from inertia and partly from the feeling that if he did require a constrained coupling in the future we might just have to change the tibial surface. What do you consider to be the significant problem with the long stem? Hard to revise?
Dr Klueber wrote "semiconstrained knees will work well just a few months, then instability occurs." (unless the ligaments are intact) Do you consider the Posterior Stabilized type of knee replacement to be "semiconstrained" because we are doing these increasingly commonly? Is the comment based on a published study?
Dave Hubbard asked about re-infusion drain. We don't have such a thing in our hospital and have put it on our wish list.
I didn't understand Rene's question about beer ;-) I relax after difficult cases by writing webpages of course!!
FROM: Dr. Derek Cooke
Re: the stemmed tibia, yes exactly, revision ease.
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