6
KNEE The arthroscopic deepening trochleoplasty Lars Blønd Philip B. Scho ¨ttle Received: 11 March 2009 / Accepted: 8 September 2009 / Published online: 14 October 2009 Ó Springer-Verlag 2009 Abstract Since a dysplastic trochlea has been identified as the main pathomorphology in recurrent patellofemoral instability, trochleoplasty became a surgical solution in some of these cases. However, in comparison to other surgical procedures stabilizing the patellofemoral joint, trochleoplasty is a major operation with an arthrotomy, and associated typical risks of open surgery such as arthrofi- brosis. Therefore, we developed a technique to perform an arthroscopic deepening trochleoplasty via suprapatellar portals using shaver burrs. Comparable to the open pro- cedure, a cartilage flake is released and a new bony trochlea is created according to the normal anatomy. Then, the cartilage flake is re-fixated using Vicryl tapes and anchors. This method seems to be an obvious advantage in patellofemoral surgery, since an arthrotomy can be avoi- ded, and postoperative pain as well as soft tissue healing time can be reduced. Keywords Patella Á Instability Á Patella dislocation Á Trochleoplasty Á Medial patellofemoral reconstruction Á Knee Introduction Chronic patellofemoral instability is a disabling condition and the surgical solution for this condition has improved owing to an increased understanding of the anatomy and pathomorphology of the unstable patellofemoral joint. Dejour [6] demonstrated in 1994 that a trochlear dysplasia is present in 90% of the cases with patellofemoral insta- bility. In order to restore anatomical abnormalities and to address the instability causing factors rather than per- forming indirect procedures, deepening trochleoplasty has been found to be a surgical solution to treat recurrent patellofemoral instability in these cases [15, 20, 21]. Although this technique is not yet performed regularly, it is a reasonable procedure to restore normal patellofemoral tracking and stability in flat or even convex trochlea mor- phology, where interventions at the passive stabilizers, i.e. the MPFL reconstruction would only increase the patel- lofemoral pressure. Until today, trochleoplasty is only described as an open procedure [11, 21] and therefore is related to higher risks of pain, scar tissue, arthrofibrosis, and infection in comparison to arthroscopic procedures. We therefore have seen the need for an arthroscopic technique. In the following, the surgical technique as well as the first results will be presented. Patients and methods Indications for trochleoplasty were two or more patellar dislocations with a persistent apprehension sign from 0° to 30° of flexion and trochlear dysplasia grade B or more as defined by Dejour et al. and regraded by Tecklenburg et al. [5, 6, 19]. The exclusion criterion was a cartilage defect in the trochlea ICRS grade 3 or 4 with a diameter of 5 mm or L. Blønd Department of Orthopaedic Surgery, Gildhøj Private Hospital, Copenhagen, Denmark P. B. Scho ¨ttle Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany L. Blønd (&) Falkevej 6, 2670 Greve Strand, Denmark e-mail: [email protected] 123 Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485 DOI 10.1007/s00167-009-0935-5

The arthroscopic deepening trochleoplasty

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Page 1: The arthroscopic deepening trochleoplasty

KNEE

The arthroscopic deepening trochleoplasty

Lars Blønd • Philip B. Schottle

Received: 11 March 2009 / Accepted: 8 September 2009 / Published online: 14 October 2009

� Springer-Verlag 2009

Abstract Since a dysplastic trochlea has been identified

as the main pathomorphology in recurrent patellofemoral

instability, trochleoplasty became a surgical solution in

some of these cases. However, in comparison to other

surgical procedures stabilizing the patellofemoral joint,

trochleoplasty is a major operation with an arthrotomy, and

associated typical risks of open surgery such as arthrofi-

brosis. Therefore, we developed a technique to perform an

arthroscopic deepening trochleoplasty via suprapatellar

portals using shaver burrs. Comparable to the open pro-

cedure, a cartilage flake is released and a new bony

trochlea is created according to the normal anatomy. Then,

the cartilage flake is re-fixated using Vicryl tapes and

anchors. This method seems to be an obvious advantage in

patellofemoral surgery, since an arthrotomy can be avoi-

ded, and postoperative pain as well as soft tissue healing

time can be reduced.

Keywords Patella � Instability � Patella dislocation �Trochleoplasty � Medial patellofemoral reconstruction �Knee

Introduction

Chronic patellofemoral instability is a disabling condition

and the surgical solution for this condition has improved

owing to an increased understanding of the anatomy and

pathomorphology of the unstable patellofemoral joint.

Dejour [6] demonstrated in 1994 that a trochlear dysplasia

is present in 90% of the cases with patellofemoral insta-

bility. In order to restore anatomical abnormalities and to

address the instability causing factors rather than per-

forming indirect procedures, deepening trochleoplasty has

been found to be a surgical solution to treat recurrent

patellofemoral instability in these cases [15, 20, 21].

Although this technique is not yet performed regularly, it is

a reasonable procedure to restore normal patellofemoral

tracking and stability in flat or even convex trochlea mor-

phology, where interventions at the passive stabilizers, i.e.

the MPFL reconstruction would only increase the patel-

lofemoral pressure. Until today, trochleoplasty is only

described as an open procedure [11, 21] and therefore is

related to higher risks of pain, scar tissue, arthrofibrosis,

and infection in comparison to arthroscopic procedures.

We therefore have seen the need for an arthroscopic

technique. In the following, the surgical technique as well

as the first results will be presented.

Patients and methods

Indications for trochleoplasty were two or more patellar

dislocations with a persistent apprehension sign from 0� to

30� of flexion and trochlear dysplasia grade B or more as

defined by Dejour et al. and regraded by Tecklenburg et al.

[5, 6, 19]. The exclusion criterion was a cartilage defect in

the trochlea ICRS grade 3 or 4 with a diameter of 5 mm or

L. Blønd

Department of Orthopaedic Surgery,

Gildhøj Private Hospital, Copenhagen, Denmark

P. B. Schottle

Department of Orthopaedic Sports Medicine, Klinikum rechts

der Isar, Technical University of Munich, Munich, Germany

L. Blønd (&)

Falkevej 6, 2670 Greve Strand, Denmark

e-mail: [email protected]

123

Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485

DOI 10.1007/s00167-009-0935-5

Page 2: The arthroscopic deepening trochleoplasty

more. Three of our patients previously have had an imbri-

cation of the medial soft tissue structures and a lateral

release, and one patient was operated twice with an Elms-

lie–Trillat procedure first, followed by an MPFL recon-

struction due to instability, but still suffering from ongoing

subluxations and pain in early knee flexion. Preoperatively,

all patients have undergone patellar-stabilizing training for

a minimum of 3 months under survey of a physiotherapist.

Since March 2008 the above-described procedure has

been performed in eight knees in seven consecutive

patients.

In one case a tourniquet had to be applied due to reduced

visualization caused by bleeding.

All patients were operated using spinal anesthesia and

20 ml of 0.25% bupivacaine and epinephrine was distrib-

uted in the incisions and intraarticular at two time points

before the incision and after wound closure. Postoperative

full weight bearing was allowed immediately after surgery,

while a knee immobilizer with limited extension of 30� and

free flexion was prescripted for 2 weeks. Postoperatively

all patients had physiotherapist-guided knee stabilizing

training for a period of 12 weeks. Clinically, the 100 mm

VAS pain score, Tegner, Kujala and KOOS scores have

been recorded preoperatively as well as during the post-

operative clinical controls, while the type of trochlear

dysplasia as well as the tibial tuberosity to trochlear groove

distances (TTTG) were evaluated preoperatively in the

MRI scans [14]. The patellar height was evaluated by

X-rays and sagittal MRI, using the Caton–Dechamps index

[2] and by MRI using patellatrochlear index, PTI.

Surgical technique

A tourniquet is mounted to the thigh, in case bleeding

occurs and reduces visualization. Initially, an arthroscopy

is performed via a standard lateral arthroscopic portal to

determine the trochlear shape and to inspect the cartilagi-

nous situation. If the preoperative indication for troch-

leoplasty (see ‘‘Patient’’ section) is verified, the procedure

is continued using further arthroscopic portals.

To have an optimal view to the bony border of the

proximal trochlea, still with the arthroscope in the lateral

portal and with the knee extended, one medial and one lat-

eral superior arthroscopic portal is set in the proximal part of

the suprapatellar bursa close to the quadriceps tendon, using

a needle as a guide. An expanding canula with an 8.25-mm

diameter is introduced in the superolateral portal. This

allows the tensioning of the knee capsule towards proximal,

giving more space and a better overview of the joint from

this proximal portal. The arthroscope is now switched to the

superomedial portal. Then, an additional lateral working

portal is placed at the level just proximal to the lateral border

of the trochlea and a canula with a diameter of 5.75 mm is

introduced (Fig. 1). Through this lateral working portal the

synovial tissue in a 10-mm-wide zone proximal to the

trochlear groove is ablated with a radiofrequency energy

device (RF) until the cortical bone is exposed.

The cartilaginous flake is then released using a 4-mm

round burr (bone cutter) shaver. This may seem to be a very

difficult step, but surprisingly the shaver blade relatively

easily finds the cleavage between bone and cartilage without

harming the cartilage. Working with the shaver blade from

side to side, switching between the two different superolat-

eral portals, slowly releases the cartilage flake until the curve

of the trochlea gets to bend (Fig. 2). In order to avoid bone

loss from the top of the lateral femoral condyle, the cartilage

in this area can be released using an osteotome.

Again using the same 4-mm round burr shaver blade, the

trochlea groove is modeled giving it a deeper and more

lateralized shape via the superolateral portal (Fig. 3). If

present, a supratrochlear bump or spur is removed in the

same way. In order to evaluate the shape and depth of the

newly modeled groove, the cartilage flake is regular pres-

sed down into the new groove, using the numb side of the

bone cutter. If the newly created trochlear groove is not yet

deep enough according to a normal anatomy, more bone is

removed in the above-described way.

The cartilage flake is re-fixated using four 3.5-mm

knotless suture anchors with an eyelet. The eyelet of the

first central anchor is loaded with one 3-mm vicryl tape and

one 1-0 vicryl suture. By working through a standard

medial portal, the hole is predrilled just distal to the hinge

of the cartilage flake, and the preloaded anchor is then

Fig. 1 This illustration demonstrates a right knee with two canulas

and with an arthroscope inserted via a superomedial portal and also

the final deepening trochleoplasty including the refixation with vicryl

tapes are figured

Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485 481

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Page 3: The arthroscopic deepening trochleoplasty

introduced into the hole, so the tape and suture are kept

fixated (Fig. 4).

A new stab incision is needed so the additional anchors

can be placed perpendicular to the bone, in the area

proximal to the cartilage flake. This stab incision is made

just medial to the proximal edge of the patella, and

beforehand correct placement is tested with a needle.

One by one the tapes are retrieved through this stab

incision and the anchors are placed at the proximal border

of the cartilage flake, holding down the flake in a spider

like configuration. A third suture anchor is loaded with the

two sutures together and inserted using the above men-

tioned techniques at the most adequate spot (Fig. 5a, b).

To achieve stability close to extension, each of the

procedures was combined with either reinsertion of the

native ligament using suture anchors at the medial epi-

condyle [3] or reconstruction [16]. The reinsertion was

performed in one case, where the MPFL was freshly rup-

tured at its femoral insertion, using suture anchors at the

anatomical femoral insertion, while the reconstruction was

performed in cases with complete rupture of the MPFL

(patellar and femoral/intramural). The MPFL reconstruc-

tion was performed in a double bundle technique with a

proximal and a distal bundle at the patellar insertion, using

an autologous Gracilis tendon. Since most of the patients

suffer from ongoing dislocation for years before surgery,

the MPFL is almost insufficient in most of the cases and the

quality is native ligament quality which is not sufficient for

reinsertion Therefore, the MPFL reconstruction is the

technique to provide stability close to extension. No

additional intervention such as a lateral release or transfer

of the tibia tuberosity has been performed.

Ethical standards

The local ethic committee of Copenhagen has approved the

study and it has been performed in accordance with the

ethical standards laid down in the 1964 Declaration of

Helsinki. All patients gave their informed consent to par-

ticipate in the study.

Fig. 2 Beginning of release in

cartilaginous trochlea in a left

knee from the lateral side (a)

and finalizing the detachment of

the cartilage flake in a right

knee (b)

Fig. 3 Creating the new bony

trochlea using a burr at the

beginning (a) and after final

remodeling (b)

Fig. 4 This demonstrates how

an anchor, loaded with tapes

and sutures, is placed in the

center of the trochlear groove

482 Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485

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Results

All patients left the hospital the morning after surgery and

besides normal analgesics (i.e., paracetamol), additional

one or two doses of morphine (p.o.) have been requested in

all cases at the day of surgery. Stitches were removed

14 days after surgery without any problem in wound

healing, except for one case that had per oral antibiotic

prescribed from her general practitioner because of a sus-

pected infection from the superolateral portal.

All patients have achieved full weight bearing from the

first postoperative day and reached the preoperative range

of motion when the knee immobilizer has been removed.

Three months postoperatively, the apprehension sign was

negative in all patients. Demographic data, i.e., patients’

age, gender, radiological findings and operation time are

referred in Table 1, while VAS scores are shown in Fig. 6.

Two patients had a re-arthroscopy, one was done as a

second look arthroscopy, simultaneous with an arthro-

scopic trochleoplasty of the other knee, and the second

patient was troubled by painful caching, and the symptoms

disappeared after rest of the ruptured patellotibial ligament

was resected. I both knees macroscopic normal cartilage

was found and only in the area where the first push lock

was placed, small differences could be observed (Fig. 7).

An MRI scan postoperatively has demonstrated a new

trochlea with good congruence of the patella and the

trochlea bump has disappeared (Fig. 8).

Discussion

The most important finding of this study is that the deep-

ening trochleoplasty can be done using an arthroscopic

technique and that the procedure seems to be less painful

compared to the open procedure. Following limitations of

this study have to be taken into account: first, the number

of patients is small, the follow-up time is short and there is

no matched group of patients having an open deepening

trochleoplasty.

Since it is known that patellofemoral instability is the

result of a combination of different pathomorphologies and

Fig. 5 Examples of refixation

of the cartilage flake, after the

flake is pressed down into the

new-formed trochlea by the

tapes and sutures, looking

arthroscopically from proximal

(a). Illustration of the refixation

looking from distal (b)

Table 1 Demographic data, radiological findings and operating time

Pt

no.

Gender Height

(cm)

Weight

(kg)

Age Insall–

Salvati

ratio

Blackburne–

Peel

ratio

Caton–

Dechamps

ratio

PTI patella

trochlea

index

TTTG

(mm)

Dejour

classification

Years

from

dislocation

Number of

dislocations

Operation

time

(min)

1a M 175 72 28 1.26 1.09 1.19 28.9 19 C 21 [50 150

2 F 168 52 21 1.55 0.92 1.29 40.7 28 D 2 [50 105

3 M 184 76 17 0.55 0.39 0.56 95.8 24 C 6 12 150

4 F 168 80 34 1.33 0.64 1.12 65.3 40 D 22 [100 120

1b M 175 72 28 1.32 1.29 1.10 49.3 18 C 13 [50 140

5 F 173 63 17 1.09 1.25 1.07 49.4 17 B 11 8 110

6 F 170 60 13 1.34 1.04 0.84 34.7 23 D 2 3 150

7 F 168 60 16 1.33 1.41 1.35 24.4 13 B 2 13 170

8 F 172 54 17 1.37 1.00 0.89 31.2 10 C 7 6 160

Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485 483

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that a dysplastic trochlea is found in 90% of the patients

with a recurrent instability, trochleoplasty became an

accepted procedure to treat recurrent instability [1, 5–7, 15,

20, 21]. However, this procedure was always combined

with an arthrotomy and a soft tissue defect.

Even though the above-described technique is a tech-

nically demanding procedure, the arthroscopically per-

formed trochleoplasty shows several advantages in

comparison to the open procedure. These advantages seem

to be reduced pain, faster mobilization, less risk for

development of arthrofibrosis and reduced scar formation.

Especially the removal of the trochlear spur seems to be an

easy and helpful procedure. It is referred in the literature

hospital stay is between 3 and 5 days after an open deep-

ening trochleoplasty in order control the pain and have the

patient mobilized [15, 21]. In this series, all patients could

leave the hospital the day after surgery with an adequate

mobilization and mild pain, controlled by regular analge-

sics. Therefore, it seems that the arthroscopic trochleopl-

asty is a procedure which can be performed safely as a 1-

day surgery, not only being economical, but also increasing

patients’ comfort.

The disadvantage of the arthroscopic trochleoplasty is

the difficulty of the technique itself and especially the

estimation of the correct shape of the new trochlea [9].

Regarding the loss of apprehension, it is difficult to

estimate if it is due to the trochleoplasty or the additional

treatment of the MPFL [20]. However, since it has been

proven biomechanically that the patellofemoral stability in

flexion of more than 30� is mainly given by the presence of

a trochlear grove, while the MPFL is the passive structure

that stabilizes the joint in extension [18]. The disappear-

ance of the apprehension in all flexion degrees indicate a

combination therapy. Therefore, the above-described

Fig. 6 Postoperative visual analog scale 100 mm (VAS) pain score

Fig. 7 Arthroscopic view of

two different knees, 6 months

postoperatively, looking from

proximal (a) and from distal (b).

The new-formed trochlea is

visible, the reattached cartilage

is healed and the sutures are

absorbed in both examples

Fig. 8 MRI scan of the same knee, 3 month postoperatively, demonstrating the trochlea bump preoperatively (a) and the new-formed trochlea

demonstrating congruence of the patella (b)

484 Knee Surg Sports Traumatol Arthrosc (2010) 18:480–485

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Page 6: The arthroscopic deepening trochleoplasty

arthroscopic trochleoplasty (stability in early flexion

degrees) is combined with an intervention, addressing the

passive stabilizers, to achieve stability close to extension,

where there is no bony guidance for the patella and passive

stabilizers are the only restraint against patellar lateralisa-

tion. Although the isolated MPFL reconstruction can pro-

vide good results in cases with a low-grade trochlear

dysplasia, the combination of both interventions is

demanding in cases with a higher grade deformity, since

the decrease of the tilt and shift, achieved by the MPFL

reconstruction leads to an increase of the patellofemoral

pressure in a dysplastic trochlea with a flat or even convex

trochlea [10]. If tilt and shift are corrected, but a physio-

logical groove is not created at the same time, the patellar

edge is pressed onto the trochlear cartilage, eventually

leading to early degeneration [8]. As it has been shown that

the cartilage viability is preserved after open deepening

trochleoplasty, no reason has been detected so far that

cartilage degeneration should occur using the arthroscopic

technique [17]. A further advantage of the arthroscopic

treatment is the integrity of the lateral patellofemoral soft

tissue complex, since all recent biomechanical studies have

shown that weakening of the lateral structures leads to

increase of the patellofemoral instability [4, 12, 13].

Especially, since the arthroscopic technique shows prom-

ising results without arthrofibrosis and a fast wound healing

as well as minimal pain, it is encouraging to proceed with

this combination procedure in terms of above explained

indications. Although early time results with a follow-up

after 1 year are promising, the 2-year follow-up, with

objective and subjective clinical and radiological results of

these relatively seldom procedures will be presented in the

future. The clinical relevance of this study is that the

deepening trochleoplasties can now be done arthroscopi-

cally and this is mainly a technical guidance. However, it

has to be noted that this procedure is technically difficult

with potential dangers, with a long learning curve; and

therefore, it can only be recommended for experienced

arthroscopist familiar with patellofemoral joint instabilities

to start doing this procedure.

Conclusion

This method seems to be an obvious advantage in patel-

lofemoral surgery, since an arthrotomy can be avoided, and

postoperative pain as well as soft tissue healing time can be

reduced. With respect to postoperative pain, scar tissue

and fast rehabilitation, the preliminary results seem

encouraging.

Conflict of interest statement We have received no financial

support and there are no conflicts of interest.

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