Date: Fri, 10 Sep 2004 22:02:25 +0200

From: Josep M. Muñoz Vives

Subject: LISS failure

I would like your thoughts and advice about this case.

This 40 yo male suffered a car accident on Monday. His lesions were:

• Anterior pneumothorax (minimal)
• Left tibia fracture (41-A3.3) closed
• Right femur fracture (33-C3.3) open grade III-A

On Wednesday we operated him, we used a LISS plate in either bone, when drilling we had the feeling of a 'normal' bone.

On Thursday afternoon he was alright, he is a very active man and he was moving well both knees. Later that evening he told me that while he was a little bit asleep he turned on the bed and felt pain and that the femur was loose. Here are the X-rays we took.

We are planning to reoperate him on Monday. Removing the screws from the LISS plate and drilling the medial cortex, using locking screws without the drilling tip.

Thanks in advance.

Dr. Josep M. Muñoz Vives
Orthopedic Dept.
Hospital Universitari Dr. Josep Trueta.
Girona
Catalunya, Spain

Date: Fri, 10 Sep 2004 22:31:01 +0200

From: J.C. Goslings

We have had similar experiences with unicortical screws in LISS femur. In this case we would remove the LISS (can be quite difficult if screws are tightly locked in the plate), connect the two condyles with cannulated screws and re-apply LISS more distally and use the (green) bicortical screws.

Good luck,

Carel Goslings

Trauma Unit dept. Surgery

Academic Medical Center

Amsterdam, the Netherlands

Date: Fri, 10 Sep 2004 15:45:54 -0500

From: Frederic B. Wilson, M.D.

Dear Josep,

I think the problem occured because the sagittal split was not recognized and/or adequately fixed. We have had this problem also. I usually fix the condylar split with cannulted screws placed so that they will not interfere with the LISS plate. The coronal splits must also be suspected and recognized. You may want to clamp the condylar fragments with the periarticular clamp prior to reinserting the locking screws. You may also want to place a lag screw in the plate, at least temporarily.

Fred Wilson

Tyler, Texas, USA

Date: Fri, 10 Sep 2004 15:57:04 -0500

From: Anglen, Jeffrey

One option would be to abandon LISS, revise it with a locking condylar plate, longer, with bicortical screws in the shaft, and lag screws in the joint segment. You can put large or small fragment lags outside the plate, and some conical head screws through the plate, in addition to locking screws.

Jeff Anglen

University of Missouri

Date: Fri, 10 Sep 2004 17:33:19 -0500

From: Andrew H. Schmidt

Although I agree with the comments of the others who have responded, I wanted to add some other information gleaned from my own experience with this device.

In this case, the fixation might have failed because of inadequate purchase of the side plate to the shaft. I say this because the initial lateral xray shows that the plate seems to be fairly anterior to the mid-axis of the femoral shaft.

Once the plate pulled off of the shaft, it continued to pull out of the distal segment. With the short unicortical screws used for shaft fixation, it is imperative that the plate be applied precisely at the midline (widest diameter) of the femur. If it is applied even slightly anterior or posterior to the midline, the screws just don t engage the cortex. You can t tell by feel, since the screws lock firmly into the plate. The only guidance that imaging provides is to visualize the plate centered exactly on the bone on a good lateral projection, which is difficult to obtain intra-operatively. I have resorted to making a 3-4 cm incision at the top of the plate so that I can verify that the plate is exactly centered over the femur at its proximal tip.

A second pearl is to place at least one or 2 lag screws between the condyles for intrafragmentary fixation before applying the LISS. Although screws were used across the coronal plane (Hoffa) fracture, I do not see any lag screws from lateral to medial. The LISS screws are designed to maintain the reduction of the distal femoral condylar mass to the shaft, but they do not function as lag screws. The intra-articular portion of the fracture demands open reduction and rigid internal fixation according to established principles; the LISS is used to then stabilize the reconstructed distal femur to the shaft.

I think that this could be revised any way that one wishes basically starting over at the beginning. The femoral condyles are first reduced and stabilized with lag screws, then whatever plate one is comfortable with could be used to bridge the metaphysis. If the LISS is used again, be sure that the plate is precisely positioned.

Andy Schmidt

Andrew H. Schmidt, M.D.

Faculty, Hennepin County Medical Center

Assoc. Professor, Univ. of Minnesota

Minneapolis, MN

Date: Sat, 11 Sep 2004 10:57:26 +0600

From: Alexander Chelnokov

Hello Josep,

JMMV> We are planning to reoperate him on Monday. Removing the screws from the LISS plate and drilling the medial cortex, using locking screws without the

Considering that even with the plate in place there was significant malalignment, with the such revision the wrong axis would remain the same. However reduction of condyles is fine, so i would temporarily transfix them by few wires from medial to lateral, then remove the plate and perform closed locked nailing. For such a pattern i prefer antegrade though no superstitons about retrograde.

Dear colleagues

Pls do not include into reply the entire initial message with all attachments. Even on hi-speed line it is senseless, and on a low speed connection(i now use PDA with a mobile phone) it is painlful to downnload huge duplications.

Best regards,

Alexander N. Chelnokov

Ural Scientific Research Institute of Traumatology and Orthopaedics

7, Bankovsky str. Ekaterinburg 620014 Russia

Date: Sat, 11 Sep 2004 13:42:22 +0200

From: Josep M. Muñoz Vives

Andrew H. Schmidt, M.D. wrote:

In this case, the fixation might have failed because of inadequate purchase of the side plate to the shaft. I say this because the initial lateral xray shows that the plate seems to be fairly anterior to the mid-axis of the femoral shaft. Once the plate pulled off of the shaft, it continued to pull out of the distal segment. With the short unicortical screws used for shaft fixation, it is imperative that the plate be applied precisely at the midline (widest diameter) of the femur. If it is applied even slightly anterior or posterior to the midline, the screws just don t engage the cortex.

I was taught not to put the plate in the middle of the shaft in a true lateral view of the femur, but rather slight anterior and internally rotated so the end part will adapt to the trapezoid shape of condyles, but still the screws will be in the maximum diameter of the shaft. On the post-op X-ray you can see a true lateral view of the femur (the posterior part of the condyles are aligned);but not of the plate (you can see them coming under). I can assure you that the plate was completely centered on the shaft.

You can t tell by feel, since the screws lock firmly into the plate. 

But you can tell by the drilling.

The only guidance that imaging provides is to visualize the plate centered exactly on the bone on a good lateral projection, which is difficult to obtain intra-operatively.

On intraoperative fluoroscopy with external rotation of the thigh we confirmed that the plate was completely centered in that case.

A second pearl is to place at least one or 2 lag screws between the condyles for intrafragmentary fixation before applying the LISS. Although screws were used across the coronal plane (Hoffa) fracture, I do not see any lag screws from lateral to medial.

I fully agree with you, we should have used lag screws between the two condyles.

Dr. Josep M. Muñoz Vives
Orthopedic Dept.
Hospital Universitari Dr. Josep Trueta.
Girona
Catalunya, Spain

Date: Sat, 11 Sep 2004 08:03:16 -0400

From: Kevin Pugh

Andy's point is valid. You must place the screws at the widest diameter to avoid the screw that is cortical only.

That being said, it can be oriented at any point on the "tube". The way I check it is to get a true "head on" view of the plate with the c-arm. If it is in the middle of the femur, you have accomplished your goal, and the screws will be safe.

In this case, the condyles require independent fixation. You have to make a joint before you can put it on the shaft.

kp

Kevin J. Pugh, MD

Chief, Division of Trauma

Department of Orthopaedics

The Ohio State University

Columbus, OH 43210

From: mike schnider

Date: Saturday, September 11, 2004, 6:55:38 PM

To my mind- remove all hardware, try to reposit the articular surface with 2-3 canulated screws, and after - fixation by ex-fix ( Fixano or AO)

M.Schnider

Haifa

Date: Sat, 11 Sep 2004 16:06:44 -0400

From: Peter Trafton

Difficult case!

Lateral x-ray does not adequately show proximal shaft & plate alignment with it. Do you think the plate was too anterior? This is an acknowledged mode of failure, as tangential unicortical screws may have minimal purchase, in spite of drill-tip passing through hard bone, and of course good torque as screw is tightened (into plate). If not easy to confirm intra-operatively, a short proximal incision can help to ensure correct alignment of plate with shaft.

Condyles have separated. Would separate (peripheral ? 3.5mm, lag screws, medial to lateral or lateral to medial outside LISS footprint) lag screws have been helpful? Intercondylar fracture needs open reduction and good interfragmentary compression.

LISS is a bit proximal, and screws are not parallel with joint line. Is there excessive valgus on appropriate AP views? You might want to check the mechanical axis using electrocautery cord stretched across knee, from center of femoral head to middle of talus.

I think revision is appropriate, if patient is in satisfactory condition. I bet proper length unicortical screws would do well in the shaft, if the plate is applied closely to its midline. Revision should address the other issues as well.

Good luck.

PG Trafton

Date: Sat, 11 Sep 2004 16:21:05 -0500

From: Obremskey, William T

I agree w/ Andy Schmidt. The plate should be more distal and more mid-line w/ shaft. Most likely very few screws were in shaft or only through anterior cortex. I would remove all, lag condyles and place LISS or LCP and assure it is central on shaft. A small proximal incision allows digital palpation to assure if needed. This is helpful in "large" patients.

Bill Obremskey

From: Josep M. Muñoz Vives

Date: Tue, 8 Mar 2005 16:39:11 +0100

This is the salvage of the failed LISS that I sent to the list on Sept.

Sorry for the delay in posting what we did.

We checked the stability of the intercondylar fracture and it was ok.

But to reassure ourselves we added an intercondylar compression screw, posterior to the LISS.

Then, we performed an standard approach to the thigh and removed all screws in the proximal part of the fracture except two. As seen on the x-ray all screws in the proximal part had been pulled out, but the holes were centered in the middle of the shaft.

Using the two screws left, we repositioned the plate in the same two holes and then drilled bicortical locking screws (green ones) ordered specially for the occasion (they dont come in the same box than the LISS).

We checked the alignment, that was considered good.

These are the post-op x-rays

Unfortunately I wont be able to follow up the patient, because he went back to Holland. May be he well come and visit me next year if he comes back on vacation, then I'll tell you what finally happens.

Dr. Josep M. Muñoz Vives
Orthopedic Dept.
Hospital Universitari Dr. Josep Trueta.
Girona
Catalunya, Spain

Date: Wed, 9 Mar 2005 02:00:15 +0500

From: Alexander Chelnokov

Dear Josep,

JMMV> These are the post-op x-rays

Excellent job. But difficult.

In case of such fracture gap probability of nonunion is >0, so dynamization could be useful trick. I wonder whether closed nailing would have been easier to accomplish. It could provide more controllable fixation with less soft tissue stripping. In our settings antegrade nailing works pretty fine in such fractures and it looks like motivation to migrate to LISS is not enough... Any suggestions?

Alexander N. Chelnokov

Ural Scientific Research Institute of Traumatology and Orthopaedics

7, Bankovsky str. Ekaterinburg 620014 Russia

From: Josep M. Muñoz Vives

Date: Wed, 9 Mar 2005 09:20:46 +0100

I wonder whether closed nailing would have been easier to accomplish.

Maybe it could have been easier. But looking at the initial x-ray, I think that only 2 screws in the coronal plane wouldn't have been enough to hold the epiphyseal and metaphyseal conminution.

It could provide more controllable fixation with less soft tissue stripping.

Although in this case we had to elevate the lateral vastus to revise it, LISS is inserted with minimal soft tissue stripping,

In our settings antegrade nailing works pretty fine in such fractures and it looks like motivation to migrate to LISS is not enough... Any suggestions?

We use LISS in selected cases of AO-OTA 33-C2 and 33-C3

when we think that 2 screws won't have enough grip, or only 1 screw will hold, because the more superior one lies in middle of comminution.

Dr. Josep M. Muñoz Vives
Orthopedic Dept.
Hospital Universitari Dr. Josep Trueta.
Girona
Catalunya, Spain