Download Tailored tibial tubercle transfer for patellofemoral malalignment

Knee Surg Sports Traumatol Arthrosc
DOI 10.1007/s00167-008-0502-5
LETTER TO THE EDITOR
Tailored tibial tubercle transfer for patellofemoral malalignment:
analysis of clinical outcomes
Reply to the comments by S. Koëter and A. Wymenga
Tamir Pritsch Æ Amir Haim Æ Ron Arbel Æ
Nimrod Snir Æ Nadav Shasha Æ Shmuel Dekel
Received: 23 January 2008 / Accepted: 25 January 2008
Ó Springer-Verlag 2008
Dear Editor:
We are very grateful to Dr. Koëter and Dr. Wymenga [2]
for their important remarks on our article [3].
No doubt that malalignment of the patello femoral joint
is a complex problem. It can arise from various reasons.
The end result however is patellar instability, which should
be treated. Patients should be selected very carefully for
any kind of operation of the patello femoral joint. Based on
many years of experience, we have learned that some times
small operations, like lateral release, are insufficient and do
not produce satisfactory results. In fact, in recent years, we
have performed many cases of lateral release with the
patient connected to quadriceps muscle stimulator. This is
done to observe the patellar tilt and the lateral subluxation
of the patella after release has been performed, and consequently determine the need for tibial tuberosity transfer.
Regarding the questions of Dr. Koëter and Dr.
Wymenga:
1.
2.
Patients in our study were operated at a mean of
6 years following the beginning of complains. During
those 6 years, they were conservatively treated with
various treatments including physiotherapy and braces.
None of the patients were instantly treated surgically,
soon after the first dislocation of the patella.
In addition to known clinical findings suggestive of
patellar instability such as apprehension test, and
patellar tilt test, another test was constantly used in
every patient. We did not describe the test in the paper
T. Pritsch (&) A. Haim R. Arbel N. Snir N. Shasha S. Dekel
Department of Orthopedic Surgery B’,
Tel Aviv Sourasky Medical Center,
6 Weitzman St, Tel Aviv 64239, Israel
e-mail: [email protected]
3.
as I found it tricky to do and evaluate. We call this test
‘‘The active instability of the patella’’. This test is
performed exactly as the CT described by Dr. Dejour
[1] in which the knee is held in 15° of flexion and the
patient is asked to extend the knee while the foot is
held in 15° of external rotation. Careful inspection and
palpation of the patella can reveal in many cases lateral
subluxation while the quadriceps is contracted. Sometimes this lateral motion is severe and sometime is
minute. It was detected in the majority of the patients.
CT scan in full extension and in flexion, exactly as
described by Dr. Dejour [1], was performed in all
patients—one cut through the middle of the patella
with and without muscle contracture. In these exposures few parameters were measured:
1.
2.
The Laurin angle in somewhat different from what
was described by Dr. Dejour [1], the line was
drawn under the femoral condyles and the other
line parallel to lateral facet of the patella.
The Marchant angle.
Surgery was indicated only when a combination of
positive clinical findings, and pathological Merchant and
Tilt angles was found.
Unfortunately we have not done all the CT measurements described by Dr. Dejour [1]. We agree that these
measurements can add to the diagnosis of patellar instability as well as to the repositioning of the tibial tuberosity.
Our decision as to how much to medialize the tibial
tuberosity during surgery was based on muscle contracture
and visualization of the patellar trucking during surgery.
We feel that this part is much more important than the CT
scan itself.
The operation was always done in four stages while the
knee is held in 15° of flexion.
123
Knee Surg Sports Traumatol Arthrosc
1.
2.
3.
4.
Before the patient was scrubbed, the quadriceps was
contracted via electric stimulation, or alternatively the
patient was requested to contract the muscle itself
when selective epidural anesthesia was used. The
amount of lateral subluxation of the patella was
evaluated, clinically.
These tests were repeated after lateral release was
performed in order to determine whether mediallization of the tibial tuberosity should be performed.
After the tibial tuberosity was placed and fitted
temporarily with one distal screw, the tracking was
evaluated till no subluxation of the patella was noticed.
At the end of the operation, after the tibial tuberosity
had been fixed to its position, the tourniquet was
released and the test repeated for the last time. The
wound was closed and operation complete only after
confirming satisfactory patellar tracking.
In very few cases we had to revise the position of the tibial
tuberosity before closure and medialize it more.
In none of our cases had we overcorrected the position
of the tibial tuberosity, and medial instability did not occur
even after moving the tibial tuberosity as far as 2.5 cm.
123
Conversely, very few patients reported a feeling of lateral
subluxation of the patella during the early postoperative
period. The intraoperative tests, simulating patellar tracking, clearly demonstrated that distalization of the tibial
tuberosity, when patella alta was present, significantly
contributed to the stability of the patella.
We hope that we have addressed all the questions of Dr.
Koëter and Dr. Wymenga and we thank them for letting us
express our views once more.
References
1. Dejour H, Walch G, Nove-Josserand L, Guir C (1994). Factors of
patellar instability: an radiographic study. Knee Surg Sports
Traumatol Arthrosc 2:19–26
2. Koëter S, Diks MJ, Anderson PG, Wymenga AB (2007) A
modified tibial tubercle osteotomy for patellar maltracking: results
at two years. J Bone Joint Surg Br 89(2):180–185
3. Pritsch T, Haim A, Arbel R, Snir N, Shasha N, Dekel S (2007)
Tailored tibial tubercle transfer for patellofemoral malalignment:
analysis of clinical outcomes. Knee Surg Sports Traumatol
Arthrosc 15:994–1002