Management of Recurrent Dislocation of Patella by Reconstruction of Medial Patellofemoral Ligament – A Noval Approach

JITESH JAINSAURABH AGARWAL

MANAGEMENT OF RECURRENT DISLOCATION OF PATELLA BY RECONSTRUCTIONING MEDIAL PATELLOFEMORAL LIGAMENT – A NOVAL APPROACH.

PATTERNS OF DISLOCATION

Recurrent dislocation –• repeated, occasional dislocation (commonest form).• The dislocations may occur at intervals of weeks or months.

Recurrent subluxation. •This implies a less drastic event than a dislocation but the distinction between the two is often unclear.• Patients with lax joints.

Habitual dislocation.• patella which dislocates every time the knee flexes.• in these cases it cannot be held in the reduced position throughout the full range of flexion.

IntroductionInstability of the patella is a common problem. The medial patellofemoral ligament (MPFL) has been demonstrated to be the major soft tissue stabilizer to prevent abnormal lateral displacement of the patella.

Desio SM et al Soft Tissue Restraints to Lateral Patellar Translation in the HumanKnee, Am J Sports Med

Anatomy

It extends between the superomedial pole of

the patella to the anterior aspect of the medial

epicondyle

The vertical distance from the superior pole of

the patella to the top of the medial

patellofemoral ligament averages about 6.1

mm.

The distal border of the VMO muscle attaches

along the majority of the proximal medial

edge of the MPFL

Steensen RN et al, Am J Sports Med. 2004;32:1509-1513.

Anatomy-Design fault?The patellofemoral joint is intrinsically unstable joint? Tibial tubercle lies lateral to the long axis of the femur and the quadriceps muscle, and the patella is therefore subject to a laterally directed force.

This apparent ‘design fault’ is

minimised by the resistance of the

lateral lip of trochlea to lateral movement of the patella during

flexion.

Biomechanics

Biomechanically, the medial patello-femoral

ligament is considered the primary passive restraint

to patellar lateral displacement, with a mean tensile

strength of 208 N

Amis AA et al, Knee. 2003;10:215-220.

Biomechanics From 0° to 30° of flexion- the median ridge of the patella lies lateral to the centre of the trochlea. 30° and 60° of flexion-it moves medially to become centred in the trochlear groove.As flexion proceeds the patella is more deeply engaged in the trochlea and is held firmly by soft-tissue tension. Beyond 90°-It tilts so that its medial facet articulates with the medial femoral condyle.

Biomechanics

Lateral patellar displacement tests in vitro showed

that the patella subluxed most easily at 20 degrees

knee flexion.

The contribution of the MPFL to resisting patellar

lateral subluxation was greatest in the extended knee

Amis AA et al, Knee. 2003,Anatomy and biomechanics of the medial patello-femoral ligament.

Factors Leading To Patellar Instability

Poor engagement abnormally high patella, patellar dysplasia or a poorly developed trochlea.

Failure to stay in the trochlea•Defective lateral trochlear margin •unusually shallow trochlear groove.•Greater laterally directed force -excessive valgus.• excessively tight lateral structures -fibrosis of the vastus lateralis or•deficient medial structures -injury to the medial retinaculum,• stretching of medial structures after repeated dislocations, •severe wasting of the vastus medialis.

Management-Options are more than 100 lateral release, medial imbrication, medial patellofemoral ligament repair, and a number of distal realignment

procedures.

Management Recently, medial patellofemoral ligament

reconstruction has gained popularity as a treatment modality for recurrent patellar instability.

Why MPFL?

Deie M et al noted that after Reconstruction of the medial patellofemoral ligament no recurrence of patellar instability was found with normalization of the congruence angle, tilt angle, and lateral shift ratio in all of their patients.Deie M, et al. J Bone Joint Surg Br2003.

Why MPFL?Drez D et alNoted in their series of 15 patients a 93% good to excellent results of medial patello-femoral ligament reconstruction in the treatment of patellar dislocation.

Autogenous hamstring or fascia lata for reconstruction Mean follow-up was 31.5 months, Drez D et al, Arthroscopy. 2001.

Why MPFL? Ellera Gomes JL et al showed in their series of 16 knees with Medial patello-femoral ligament reconstruction with semitendinosus autograft for chronic patellar instability 94% of patient outcomes were rated good or excellent according to the Crosby-Insall criteria.88% of the patients were satisfied with their surgery 15 knees showed a negative apprehension test at follow-up.

Arthroscopy. 2004

Why MPFL MPFL is injured in most cases with acute patellar dsilocation and MPFL insufficiency is present in all cases with recurrent patellar dislocation.

…Now, the role of the MPFL has been almost established in the Management of Dislocations of patella.

Material and methods 14 Patients with patellar instability were enrolled in this study from 2008-2012

5 habitual dislocation 9 Recurrent dislocation

Medial patellofemoral ligament pathology was confirmed by both clinical and radiological examination. Apprension test was positive in 12 patientsAverage Q angle..

The MPFL is attenuated without a discrete tear noted with a laterally dislocated patella

There is complete avulsion of the MPFL at the femoral attachment and a tear at the patellar attachment

Material and methods

Technique• Arthroscopic reconstruction of the medial

patellofemoral ligament was done using hamstring graft looped around the patella and anchored to the medial epicondyle of femur with either bone staples or Interference Screws.

• Postoperatively above knee brace support was given for 3 weeks with intermittent physiotherapy and gradual mobilization.

Material and methods

Non-anatomic reconstruction of the MPFL can lead to non-physiologic patello-femoral loads and kinematics.So the goal of surgical intervention must be an anatomic reconstruction.

Amis AA et al Anatomy and Biomechanics of the Medial Patellofemoral Ligament, Knee 2003.

Technique – Graft Harvesting

Technique – Graft Preparation

Technique – Patellar Preperation

Graft Loop Through Patella

Graft was passed through a Soft Tissue Tunnel between Medial Retinaculum and Joint Capsule

Graft Fixed to the Medial Epicondyle of Femur

Results

13 out of 14 patients returned to their daily work and sport activities within 6 weeks to 3 months.

1 patient had stiffness around knee post surgery with ROM 10-1000. 100 flexion deformity was gradually corrected with supervised physiotherapy over next 3 months.

Results

Complications: Anterior knee pain-3 Patients. Numbness -5 patients experience mild

numbness on the shin, close to the surgical scar.

No case of graft rupture and infection was noted

Case-1

Case -1; 2 Years Post-Up

Case – II , Pre-op

Case – II, Post-op

Case III, 35 years Male6 Years Follow-Up

3 Years Follow-Up

Case-IV

Conclusion The principal advantage of this procedure is

the ability to definitively reconstruct the medial patellofemoral ligament on the femur.

Allowing reasonable MPFL isometry throughout the arc of knee motion.

A minimal invasive surgery. With this procedure early rehabilitation can

be started and is a good technique for sport persons with MPFL injuries.

THANK-YOU