Patellar Dislocation and Subluxation

Medial Patellofemoral Ligamant Reconstruction
   
Yokohama Orthopaedic Clinic New Knee Surgery Communication
Patellar dislocation or subluxation of the patella is a disorder that most commonly in adolescents, especially in young athletes and dancers. Nonoperative treatment often results in recurrent dislocations and diminished knee function. However, surgical treatments have associated morbidity and are not guaranteed to relieve symptoms. Many surgical techniques, both proximal and distal realighment, have been used with varying success and postoperative morbidity.

Numerous etiologic predisposing factors for recurrent dislocation or subluxation of the@patella have been mentioned in the literature, and over 130 different operative methods have been described with the goal of correcting and/or eliminating patellofemoral instability and pain. Operation methods can be classified as proximal realignment, distal realignment, proximal and distal realignment, lateral retinacular release and medial retinacular plication.The purpose of these realignment procedures has been focused especially on the correction of the dynamic elements that intend to straighten the direction of the pull of the extensor mechanism and reduce the force tending to laterally displace the patella from the troclea.

Although most authors indicated that the results are usually satisfactory and recurrence is uncommon, various problems have been indicated. These include recurrence of dislocation, remaining patellofemoral instability without redislocation, patellofemoral osteoarthritis, loss of flexion, and medial subluxation. Fithian stated that surgical treatment has not been uniformly successful. Aichroth described that no single procedure would be appropriate dfor all types of recurrent patellar dislocation and consequently, combinations of different methods are frequently necessary. And all the combinations of the various operations are chosen, unavoidably, in severe cases or failed operative treatments. Hughston noted in 1984 that we come to three-quarters of a century from the time of Roux (1888) and Krogius (1904) and yet their concepts and techniques are still with us today.

Over the past decade, attention has begun to be directed to the medial patellofemoral ligament (MPFL) as a restraint of lateral patellar translation. In 1957, Kaplan first referred to the transverse retinacular ligament that afterwards became known as the MPFL. Although there were few reports before 1990, many clinical and basic reports indicating the importance of the MPFL in patellar subluxation and dislocation have been published in the past decade. Several researchers have reported that the MPFL has 50-60% of the total medial restraining force and the MPFL is the primary restraint among the medial patellar stabilizers. We reported that the MPFL is injured in most cases with acute patellar dsilocation and MPFL insufficiency is present in all cases with recurrent patellar dislocation. Now, the importance of the MPFL has been almost established.

In 1992, we first presented a preliminary report on MPFL reconstruction using the artificial ligament for recurrent patellar dislocation in Japan. This report was one of the earliest MPFL reconstruction reports in the world. We have gradually made several improvements in the reconstruction method, and we showed in the Knee Journal (Knee 2000) that the results with a mid-term follow-up after reconstruction was good. In the paper of Arthroscopy Journal (Arthroscopy 2003), we presented a detailed surgical procedure of MPFL reconstruction for recurrent patellar dislocation and theanatomical, biomechanical and clinical rationale. Beasley (2004) indicated a promising anatomic MPFL reconstruction instead of the vast number of the traditional non-anatomic extensor mechanism reconstruction. Finally in 2006 we developed a new hybrid MPFL reconstruction using the autogenous tendon and this technique was published in Arthroscopy jounrnal (Arthroscopy 2006). This technique is applicable to most cases of recurrent patellar dislocation. Postoperative management is followings: On 1st day postsurgery, the patient can walk with cruches. Continuous passive nmotion is started within 0-80 degrees of knee flexion. the knee flexion angle is increased by 10 degrees every one day. On the 7th day postsurgery, full weight bearing is aloowed. The patient may discharge after 8th operative day. Jogging and mild sports activities are permitted at 8 weeks and full sports activities at 12 weeks.

The key attributes of MPFL reconstruction are: 1) Reconstruction of a ligament which is anatomically present,
@@@2) Surgical technique which can be performed consistently in spite of the different degrees of patellar instability,
@ @ 3)
Surgical technique that minimizes damage to the extensor mechanism. 

To date, we have performed more than 400 MPFL reconstructions.
From the results, we stress that MPFL reconstruction is better than all former operations.
In 2008, we have developed a new MPFL reconstruction technique. This is the most reliable and safest technique. It s very difficult to treat haitual patellar dislocation. There have been no reliable reconstruction technique for habitual patellar dislocation cases. However, we recently have developed new reconstruction technique for habitual patellar dislocation. The success rate is very high. We are going to present these results in the near future in the world congress.



Profile Eiki Nomura, MD
@CEO of Eishinkai Medical Corporation
@Head of Yokohama Orthopaedics Cinic
@2-5-8,Okano, Nishi-ku, Yokohama, Japan
E-mail If you have any question,
@please do not hesitate to conatct us
@@@adress: kneetopks@yahoo.co.jp