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Case report

Simultaneous MPFL and LPFL reconstruction for recurrent lateral patellardislocation with medial patellofemoral instability

Masashi Kusano a, Shuji Horibe b,*, Yoshinari Tanaka c, Yasukazu Yonetani d, Takashi Kanamoto c,Yoshiki Shiozaki a, Yuzo Yamada e

aDepartment of Orthopaedic Surgery, Seifu Hospital, Sakai, JapanbOsaka Prefecture University, Graduate School of Comprehensive Rehabilitation, Habikino, Japan

cDepartment of Sports Orthopaedics, Osaka Rosai Hospital, Sakai, JapandDepartment of Orthopaedics, Osaka University Graduate School of Medicine, Suita, JapaneDepartment of Orthopaedic Sports Medicine, Osaka Kousei-Nenkin Hospital, Osaka, Japan

Received 8 November 2013; accepted 22 November 2013

Available online 31 January 2014

Abstract

We report an extremely rare case of both recurrent lateral patella dislocation and medial patellofemoral instability, following prior operationsto correct patella maltracking. Manual translation of the patella revealed medial and lateral instability with a positive apprehension sign. 3-Dcomputer modelling of kinematics based on MRI data demonstrated that the patella deviated laterally at full extension and translated medi-ally with knee flexion. The medial and lateral patellofemoral ligaments were reconstructed simultaneously with hamstring tendons, alleviatingperipatellar pain and patellar instability in both directions.Copyright� 2014, Asia Pacific Knee, Arthroscopy and Sports Medicine Society. Published by Elsevier (Singapore) Pte Ltd. This is an open accessarticle under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Keywords: Instablity; Lateral patellofemoral ligament; Medial patellofemoral ligament; Patella; Reconstruction

Introduction

Patella dislocation is a common clinical condition wherestatic and dynamic forces laterally displace the patella in mostcases. Reconstruction of the medial patellofemoral ligament(MPFL) has become the current, popular treatment for recur-rent lateral dislocation.1e3 Subluxation or dislocation of thepatella in a medial direction, on the other hand, is a rarecondition often seen as a late complication of lateral retinac-ular release procedures with or without tibial tubercle transferfor patellofemoral joint disorders.4e9 Medial retinacularrelease, lateral retinaculum repair, and reconstruction of thelateral patellofemoral ligament (LPFL) are surgical pro-cedures reported to have satisfactory outcomes for medial

ka Prefecture University, Graduate School of

3-7-30 Habikino, Habikino, Osaka 583-8555,

fax: þ81 72 255 0051.

ehab.osakafu-u.ac.jp (S. Horibe).

Asia Pacific Knee, Arthroscopy and Sports Medicin

D license (http://creativecommons.org/licenses/by-n

rt.2013.12.005

dislocation.5e7 However, there have been no specific reportson patients with both recurrent lateral patellar dislocation andmedial patellar instability. The following case study examinesan affected patient who was successfully treated with simul-taneous reconstruction of the MPFL and LPFL.

Case report

A 40-year-old woman presented with peripatellar pain in theleft knee and a sense of patellar instability in both lateral andmedial directions. The pain and lateral instability began afterher first lateral dislocation at age 15, and the Roux-Goldthwaitprocedure was performed with loose body removal 9 monthslater for distal realignment of the extensor mechanism. Thepatient continued to experience patellar instability and the kneegiving way postoperatively. Thirteen years after the procedure,lateral release for unstable patella was also performed. Despitethe two operations, patellar instability and peripatellar pain

e Society. Published by Elsevier (Singapore) Pte Ltd. This is an open access

c-nd/4.0/).

43M. Kusano et al. / Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology 1 (2014) 42e46

persisted. When the patient visited our hospital, she could notwalk without crutches due to the severe instability. Manualtranslation of the patella revealed medial as well as lateralinstability, with a positive apprehension sign. The Q angle of theleft knee was 25�, and plain radiographs revealed a sulcus angleof 138�, a congruence angle of�25�, and an Insall-Salvati ratioof 1.25 (Fig. 1). Three-dimensional computer modelling of ki-nematics compiled from MRI data, a technique reported byYamada et al.,10 demonstrated that the patella deviated laterallyat full extension and shifted medially with flexion (Figs. 2, 3).Non-operative treatment, including stretching the retinaculumand strengthening quadriceps, had no effect. We diagnosedrecurrent lateral patellar dislocation combined with medialpatellofemoral instability in the patient and planned MPFL andLPFL reconstruction using medial hamstring tendons as atherapeutic solution.

Under anaesthesia, the patella dislocated laterally andmoved medially to a great extent with ease. The harvestedautogenous semitendinous and gracilis tendons were folded toform double-looped grafts for the MPFL and LPFL, respec-tively. On the femoral side of the grafts, EndoButton CL(Smith & Nephew Endoscopy, Andover, MA, USA) wasplaced on each loop end after measuring the length of thefemoral tunnel. On the patellar side, two no. 2 braided poly-ester sutures were added to the free end of each graft using theKrackow technique. Both medial and lateral retinaculum wereexposed and incised transversely to expose insertion sites forthe MPFL and LPFL. A guide wire was inserted from theinsertion point for the MPFL located superoposterior to themedial epicondyle and just distal to the adductor magnus.11

Another guide wire was inserted through the iliotibial bandfrom the femoral insertion point for the LPFL located super-oposterior to the lateral epicondyle.7,12 Each femoral tunnelwas created by over-drilling along the guide wire with a 6-mmcannulated drill bit matched with the graft diameter to 20 mmin depth after over-drilling with a 4.5-mm drill bit to the far

Fig. 1. Preoperative plain radiographs. (A) Anterior-posterior (standing). (B

femoral cortex. Next, two parallel guide pins were thentransversely inserted into the patella, and over-drilled with a4.5-mm cannulated drill bit on both sides up to a depth of1.5 cm. Each graft was introduced through their respectivefemoral tunnel and fixed on the lateral femoral cortex byflipping the EndoButton. The free ends of each graft wereintroduced in the shared patella tunnels and simultaneouslyfixed on the contralateral side by tying the suture over theEndoButton at 45� of knee flexion without causing patellarsubluxation (Fig. 4). The knee was immobilized for 2 weekspostoperatively, and partial weight bearing was allowed at 3weeks and full weight bearing was started at 5 weeks.

At a 2-year follow-up, the absence of dislocation led to thedisappearance of peripatellar pain and a negative sign ofapprehension in medial and lateral directions. Postoperativeplain radiographs revealed improvement in a congruence angle(Fig. 5). As a result, it changed from �25� to �11�. Post-operative kinematic three-dimensional computer modellingshowed improvement in patellar maltracking, which includeda reduction of lateral deviation in terminal extension andimprovement of medial shift in knee flexion (Figs. 6, 7).

Discussion

Recent anatomical and biomechanical studies have revealedthat the MPFL is a major stabilizer in lateral patellar trans-lation.13e15 Reconstruction of this ligament is thus consideredto be an appropriate treatment for lateral patellar disloca-tion.1,3 Distal extensor mechanism realignment and lateralretinacular release procedures for this dislocation, however,could cause medial subluxation of the patella as a post-operative complication.9,16,17 In this case study, prior Roux-Goldthwait and lateral release procedures without recon-struction of medial restraints such as the MPFL were consid-ered to be the cause of not only persistent lateral instability butalso iatrogenic medial instability. Cases of patellar instability

) Lateral (gravity sag view). (C) Axial. A congruence angle is �25�.

Fig. 2. Three-dimensional computer modelling of patellar kinematics compiled from preoperative MRI data. Knee flexion was simulated at (A) 0�, (B) 20�, (C)30�, and (D) 50�. The patella deviated significantly laterally at full extension and shifted medially in a flexed position.

44 M. Kusano et al. / Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology 1 (2014) 42e46

in both directions have not been reported in detail, particularlywith respect to surgical treatment. Shellock et al. found“lateral-to-medial subluxation” in 9% of knees with persistentsymptoms after lateral release through examination of two-dimensional kinematic MRIs, where the patella shifted from

Fig. 3. A series of the preoperative movement of the patella.

slight lateral subluxation in extension to medial subluxation in30�of knee flexion, although no further information aboutpathology or treatment was reported.8

Kinematic three-dimensional computer modelling canclearly visualize patterns of patellar maltracking, a conditionof significant lateral deviation in extension and medial shift inknee flexion. For maltracking treatment, reconstruction of the

Fig. 4. A schematic of lateral and medial patellofemoral ligament

reconstruction.

Fig. 5. Plain radiographs at final follow up: (A) anterior-posterior; (B) lateral; (C) axial. A congruence angle is �11�. EndoButtons on the patella were removed.

45M. Kusano et al. / Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology 1 (2014) 42e46

MPFL is undoubtedly necessary to prevent further lateraldislocation. The lateral retinaculum, which acts as a restrainton the patella to avoid medial deviation, had to be repaired inthis patient due to complaints of medial patellar instability aswell as lateral instability. However, Abhaykumar et al. re-ported an almost complete absence of tissue lateral to thepatella in four cases of medial patellar dislocation followingtibial tubercle transfer surgery and lateral release.18

Fig. 6. Three-dimensional computer modelling of patellar kinematics compiled fro

30�, and (D) 50�. The patella settled in the trochlear groove at full extension, and

Reconstruction of the tissue is thus a reasonable option tolimit medial shift; Teitge et al. reported excellent results withreconstruction of the LPFL to treat patellar instability afterfailed lateral release.7 Even though Teitge et al. used aquadriceps tendon for their LPFL graft, we chose the gracilistendon because we had previously used the semitendinoustendon for the MPFL and the use of the gracilis which couldbe harvested from the same site was reasonable.1

m postoperative MRI data. Knee flexion was simulated at (A) 0�, (B) 20�, (C)medial shift at the flexed position improved.

Fig. 7. A series of the postoperative movement of the patella.

46 M. Kusano et al. / Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology 1 (2014) 42e46

Both grafts were fixed at 45�of knee flexion on the basis ofreport on MPFL reconstruction by Toritsuka et al.1 A suitablefixation angle of the LPFL graft is unknown due to few re-ports on LPFL reconstruction. However, the MPFL and thelateral capsular structures including the LPFL have a similarcharacteristic in that their contribution to the patella stabili-zation is greatest in the extended knee.12,13 Therefore weconsider that fixation of both grafts at the same angle isacceptable.

The efficacy of reconstruction for our patient was evalu-ated postoperatively with kinematic three-dimensional com-puter modelling from MRI data. The lateral deviation of thepatella improved and was found in the trochlear grooveduring terminal extension, but medial shift of the patellapersisted during knee flexion, although its degree decreased.One reason for this partial success is the prior Roux-Goldthwait procedure the patient underwent, in which thelateral half of a split patellar tendon was detached from thetibial tubercule, transferred beneath the intact medial half,and sutured to the soft tissue; these measures made it difficultto later restore the tendon to its original position. Despite thiscomplication, clinical symptoms, including peripatellar painand a sense of instability in both directions, disappeared after2 years with a negative apprehension sign. Reconstruction ofboth the MPFL and LPFL is thus a valuable procedure forrecurrent lateral patellar dislocation concurrent with medialpatellofemoral instability.

Consent

Written informed consent was obtained from the patient forpublication of this case report and any accompanying images.A copy of the written consent is available for review from theEditor-in-Chief of this journal.

Conflicts of interest

The authors declare that they have no financial or non-financial conflicts of interest related to the subject matter ormaterials discussed in the manuscript.

Authors’ contributions

All authors co-wrote the paper and discussed the results andcommented on the manuscript. All authors read and approvedthe final manuscript.

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