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Review Article| Volume 33, 101993, October 2022

Baksi procedure for habitual dislocation of patella in children – Revisiting the key surgical steps

Published:August 18, 2022DOI:https://doi.org/10.1016/j.jcot.2022.101993

      Abstract

      The pes anserinus transfer procedure for habitual dislocation of patella described by Baksi is a biomechanically sound technique with predictable long term results. The dynamic pes anserinus sling counteracts the lateral quadriceps contracture and keeps patella relocated till the vastus medialis activity is restored and takes over. The procedure is especially suitable for children with open physeal growth plates. Moreover, the surgery runs a low complication rate. In the present review, we recapitulated the steps of the procedure to illustrate its surgical basics. We also describe our experience and long term follow up results of 4 cases operated with same technique. The indigenous Baksi's procedure remains a viable option for managing habitual patellar dislocations in pediatric age group with immature skeleton.

      Keywords

      1. Introduction

      Habitual dislocation of patella in children has remained a disease with scant experience till date.
      • Gao G.X.
      • Lee E.H.
      • Bose K.
      Surgical management of congenital and habitual dislocation of the patella.
      • Joo S.Y.
      • Park K.B.
      • Kim B.R.
      • Park H.W.
      • Kim H.W.
      The 'four-in-one' procedure for habitual dislocation of the patella in children: early results in patients with severe generalised ligamentous laxity and aplasia of the trochlear groove.
      • Mittal R.
      • Balawat A.S.
      • Manhas V.
      • Roy A.
      • Singh N.K.
      Habitual patellar dislocation in children: results of surgical treatment by modified four in one technique.
      • Mittal R.
      • Sitender
      • Jain S.
      • Shukla A.
      Habitual patellar dislocation - management by two in one procedure, short term results.
      • Musielak B.J.
      • Premakumaran P.
      • Janusz P.
      • Dziurda M.
      • Koch A.
      • Walczak M.
      Good outcomes of modified Grammont and Langenskiöld technique in children with habitual patellar dislocation.
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      Although several treatment options have been described in literature, no consensus still exits.
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      The options in children are further limited by the presence of growing epiphysis restricting tibial bony procedures. In general, it is agreed that a combination of procedures involving proximal and distal reconstructions will be required for patellar dislocations.
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      There are striking differences in the pathophysiology of habitual, recurrent and permanent dislocation of patella in children.
      • Gao G.X.
      • Lee E.H.
      • Bose K.
      Surgical management of congenital and habitual dislocation of the patella.
      • Joo S.Y.
      • Park K.B.
      • Kim B.R.
      • Park H.W.
      • Kim H.W.
      The 'four-in-one' procedure for habitual dislocation of the patella in children: early results in patients with severe generalised ligamentous laxity and aplasia of the trochlear groove.
      • Mittal R.
      • Balawat A.S.
      • Manhas V.
      • Roy A.
      • Singh N.K.
      Habitual patellar dislocation in children: results of surgical treatment by modified four in one technique.
      • Mittal R.
      • Sitender
      • Jain S.
      • Shukla A.
      Habitual patellar dislocation - management by two in one procedure, short term results.
      • Musielak B.J.
      • Premakumaran P.
      • Janusz P.
      • Dziurda M.
      • Koch A.
      • Walczak M.
      Good outcomes of modified Grammont and Langenskiöld technique in children with habitual patellar dislocation.
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      In the habitual type, the patella dislocation is manifested during each flexion movement of the knee. The same spontaneously relocates following knee extension. This variety is associated with contractures of soft tissue superolateral to the patella as well as laxity of medial stabilization. A few patients of habitual dislocation also have associated skeletal abnormalities such as genu valgum, patella or trochlear dysplasia. On the other hand, the episodic recurrent type is generally without lateral contractures. The predominant pathology is believed to be weak medial stabilization arising out of reduced activity of the vastus medialis, generalized joint laxity, or post traumatic medial capsular laxity. In permanent dislocation, the patella remains dislocated in all positions of the knee. This variety is often the combined result of numerous skeletal and soft tissue pathologies.
      Baksi (1981) published a series of patellar dislocations treated surgically using an indigenous procedure based on a sound understanding of local anatomy and muscular physiology.
      • Baksi D.P.
      Restoration of dynamic stability of the patella by pes anserinus transposition. A new approach.
      His study involved 31 patients, of which 24 were under 17 years. There were 17 patients (21 patellae) which had habitual dislocations. The author very clearly distinguished recurrent from habitual and permanent dislocations based on lateral contracture. He recognized the need for a dynamic stabilizer for patellar tracking during different stages of knee flexion. He postulated that the pes anserinus transposition not only served as a physiological sling but also provided a broad based anchorage of patella to proximal tibia. Clinically, there was no recurrence of the dislocation or subluxation of the patella in any of the patients. At a mean follow up of 51 months, results were excellent in 21 patients, good in 13 and fair in two.
      Twelve years later, Baksi (1993) reexamined the results of his pes anserinus procedure in a larger cohort and with longer follow up.
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      Ninety six knees in 78 patients were reviewed at a mean of 9 year 8 months. The medial stability of the patella improved in all the cases. There were only 4 recurrences and that too were due to technical errors resulting from inadequate release of superolateral contracture or incorrect pes anserinus transfer. When these were revised, no further recurrences occurred. The procedure fared well for all three types of dislocation and was particularly useful for children with open physis.
      The current report briefly illustrates the key steps of Baksi's procedure. We also present our first-hand experience in 4 cases operated using the procedure and long term outcome obtained. The aim of the series is to make practicing clinicians aware of this option for managing habitual dislocation of patella in pediatric age group and clinical outcome expected in long term.

      2. Baksi's pes anserinus transposition procedure for dislocation of patella
      • Baksi D.P.
      Restoration of dynamic stability of the patella by pes anserinus transposition. A new approach.
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      • Baksi D.
      • Pal A.
      • Baksi D.
      Electromyographic investigation of unstable patella before and after its realignment operation.

      The procedure is conducted under tourniquet control (Fig. 1). There are two incisions: superolateral, starting approximately 8 cm proximal to patella for lateral contracture release, quadriceps alignment and medial reefing. The other incision is inferomedial extending from mid-patellar level down to the pes anserinus insertion for its transposition.
      Fig. 1
      Fig. 1The surgical steps of Baksi's pes anserinus transfer for habitual dislocation of patella: A. Skin markings for incisions B. Identification of vastus lateralis C. Mobilization of vastus lateralis from proximal patella, rectus femoris and iliotibial tract D. Plane between rectus femoris and vastus intermedius identified E. After lateral capsular and vastus lateralis release, if patella is still unstable in trochlear groove, rectus femoris is resected F. If still unsuccessful, vastus intermedius is sectioned too G. Following this, patella always reduces in the trochlear groove H. Vastus lateralis is sutured to distal cut ends of rectus femoris and vastus intermedius I. Completed quadriceps repair and alignment J. Pes anserinus harvest is planned along with 1 cm distal sleeve of periosteum K. Attachment of pes anserinus to anteromedial aspect of patella and adjoining patellar tendon L. The completed repair.
      Proximal reconstruction: The release of superolateral contracture is almost always required in habitual dislocations. The release is carried out till patella remains seated in the intercondylar groove in a fully-flexed knee. This may require dissection down to the ligamentum patellae starting from illiotibial tract proximally released through the lateral capsule. It is necessary to mobilize vastus lateralis by detaching it proximally from patella, medially from rectus femoris and laterally, iliotibial tract. The undersurface of patella should be inspected for any chondromalacic changes. An à la carte approach is adopted hereafter. If following above division, patella is reduced in knee fully flexed position, then cut proximal end of vastus lateralis is stitched to the side of rectus femoris. When this is not successful, the musculotendinous junction of rectus femoris is incised transversely. Additional release of vastus intermedius tendinous fibres, if the same are also contracted, is carried out at the same level. Following this, patella always reduces in the trochlear groove. The quadriceps mechanism is then reconstructed and aligned by suturing together proximal cut end of vastus lateralis to distal cut ends of rectus femoris and vastus intermedius. The proximal cut ends of rectus femoris and vastus intermedius are anchored to the side of vastus lateralis muscle at a higher level without tension. Further strengthening is provided by reefing together intervening portions of vastus lateralis to vastus medialis.
      Distal reconstruction: The distal 3 quarters of the pes anserinus insertion are approached through a reversed L-shaped incision. The fibrous insertion of pes anserinus along with 1 cm distal sleeve of periosteum is detached subperiosteally and prised upward. The patella is held down and medially in the trochlear groove while the flap is sutured as high as possible on anteromedial surface of patella and adjacent ligamentum patellae with the knee fully extended position. The whole tibial insertion of pes anserinus should not be harvested as it will result in its failure to act as a sling.
      Post closure, the limb is protected in compression bandage and above knee plaster slab for 2–3 weeks. Static quadriceps exercises are started early, generally on 2nd postoperative day. Weight bearing in cast may be permitted, if pain is tolerated. Knee bending and active quadriceps exercises are started following removal of cast. With a supervised exercise protocol, the extensor lag and full knee flexion mostly recovers within a span of 1–3 months.
      Our experience with the technique (Fig. 2, Fig. 3, Fig. 4, Fig. 5): There were 2 females and 2 males. All patients were immature at the time of procedure with age range 8–10 years (mean 9.25 years). One patient had right sided involvement while others had left patellar dislocations. The quadriceps lag disappeared by 5 months post procedure in all patients. The mean follow up was 74.5 months (range 40–138 months). There was no recurrence or patellar instability in any of the cases. The mean Kujala score before surgery was 46.5 which improved to 97 after the procedure (Table 1). There were no complications of patellar fracture or infection, decreased range of motion or growth impairment. The procedure provided permanent patella stability with proper tracking.
      Fig. 2
      Fig. 2Patient 1: A,B. Habitual dislocation of left patella in a 10 year old child C,D. Follow up 60 months. Matching quadriceps strength in left lower limb E,F. Full knee range of motion. No recurrence and patella stable in knee flexed position.
      Fig. 3
      Fig. 3Patient 2: A,B. Eight year child having right sided habitual dislocation of patella C,D. Follow up 138 months. Active straight leg raising and quadriceps strength demonstrated for both limbs E,F. No restriction in knee movements. No patellar instability.
      Fig. 4
      Fig. 4Patient 3: Left sided habitual dislocation in a 10 year girl C,D. Follow up 40 months. This child recovered quadriceps power by 4 months. Figure illustrating no extensor lag at follow up and comparable straight leg raising in both limbs E,F. Patella stable in knee flexed position and full knee range of motion at above follow up.
      Fig. 5
      Fig. 5Patient 4: A,B. Habitual dislocation of left patella in a 9 year old child. The dislocation occurred each time when knee was flexed 30° C,D,E,F. Knee function and strength post Baksi's procedure 60 months. There were no recurrences.
      Table 1Our experience in 4 patients with Baksi's technique.
      S.no.Age (years)SexSideFollow up (months)Kujala score
      Kujala score (Anterior Knee Pain Scale) is a patient reported assessment and incorporates subjective symptoms and functional limitations. It is a questionnaire based on 13 parameters that total up to 100 points. The parameters assessed in relation to knee joint are limp, pain, swelling, flexion deformity, atrophy of thigh, abnormal painful movements of patella, weight bearing, walking distance and experience during stairs activity/squatting/running/jumping/prolonged sitting with knee flexed.10
      (preoperative)
      Kujala score
      Kujala score (Anterior Knee Pain Scale) is a patient reported assessment and incorporates subjective symptoms and functional limitations. It is a questionnaire based on 13 parameters that total up to 100 points. The parameters assessed in relation to knee joint are limp, pain, swelling, flexion deformity, atrophy of thigh, abnormal painful movements of patella, weight bearing, walking distance and experience during stairs activity/squatting/running/jumping/prolonged sitting with knee flexed.10
      (follow up)
      1.10MLeft604696
      2.8FRight1384996
      3.10FLeft404898
      4.9MLeft604398
      a Kujala score (Anterior Knee Pain Scale) is a patient reported assessment and incorporates subjective symptoms and functional limitations. It is a questionnaire based on 13 parameters that total up to 100 points. The parameters assessed in relation to knee joint are limp, pain, swelling, flexion deformity, atrophy of thigh, abnormal painful movements of patella, weight bearing, walking distance and experience during stairs activity/squatting/running/jumping/prolonged sitting with knee flexed.
      • Ittenbach R.F.
      • Huang G.
      • Barber Foss K.D.
      • Hewett T.E.
      • Myer G.D.
      Reliability and validity of the Anterior Knee Pain Scale: applications for use as an epidemiologic screener.

      3. Discussion

      The management of habitual patellar dislocation in pediatric age group is a complex undertaking. In children, this condition requires an early treatment as delay makes the joint prone to pain, cartilage damage, and subsequent osteoarthritis. There are several elements to the pathology underlying this condition: patellar off tracking, lateral contractures/bands, wasting or lax medial tissues, trochlear dysplasia or proximal tibial abnormalities.
      • Kraus T.
      • Lidder S.
      • Švehlík M.
      • et al.
      Patella re-alignment in children with a modified Grammont technique.
      The presence of a physeal plate makes management of this condition further challenging in young children. There is risk of progressive genu recurvatum if the physis is damaged. The much acclaimed medial patellofemoral ligament (MPFL) reconstruction frequently used for recurrent dislocations is considered ineffective for habitual dislocations.
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      A general consensus has gradually evolved that a combination of surgical procedures addressing extensors and distal patellar biomechanics should be used for habitual patellar dislocations in children
      • Batra S.
      • Arora S.
      Habitual dislocation of patella: a review.
      (Table 2).
      Table 2Comparison of surgical steps of some key procedures described for managing habitual dislocation patella in children.
      ProceduresProximal reconstructionDistal reconstructionReported complications
      May be underreported because of limited number of patients and absence of long term follow up in most series.
      Baksi's procedure
      • Baksi D.P.
      Restoration of dynamic stability of the patella by pes anserinus transposition. A new approach.
      ,
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      Lateral release, lengthening of quadriceps mechanism and medial plication of vastus medialisPes anserinus transferQuadriceps lag; terminal limitation of flexion of knee; chondromalacia patellae, retropatellar degeneration; saphenous nerve irritation; stitch infections; wide prominent operation scars
      ‘4’ in one procedure and modifications
      • Joo S.Y.
      • Park K.B.
      • Kim B.R.
      • Park H.W.
      • Kim H.W.
      The 'four-in-one' procedure for habitual dislocation of the patella in children: early results in patients with severe generalised ligamentous laxity and aplasia of the trochlear groove.
      ,
      • Mittal R.
      • Balawat A.S.
      • Manhas V.
      • Roy A.
      • Singh N.K.
      Habitual patellar dislocation in children: results of surgical treatment by modified four in one technique.
      Lateral release, patellar tenodesis, proximal ‘tube’ realignment (sectioned vastus medialis sutured to vastus lateralis forming a ‘tube’)/vastus medialis obliquus reefingRoux Goldthwait patellar tendon transpositionAnterior knee pain; marginal skin necrosis; patellar instability
      ‘2’ in one procedure-
      • Mittal R.
      • Sitender
      • Jain S.
      • Shukla A.
      Habitual patellar dislocation - management by two in one procedure, short term results.
      Extensive but graded lateral releaseRoux Goldthwait patellar tendon transpositionNone reported
      May be underreported because of limited number of patients and absence of long term follow up in most series.
      Modified Grammont and Langenskiöld technique
      • Ittenbach R.F.
      • Huang G.
      • Barber Foss K.D.
      • Hewett T.E.
      • Myer G.D.
      Reliability and validity of the Anterior Knee Pain Scale: applications for use as an epidemiologic screener.
      Langenskiöld procedure (patellar reduction into femoral groove through a new opening inside the synovium)Grammont procedure (medial transfer of patellar ligament without detaching its distal insertion)Positive apprehension test; anterior knee pain
      a May be underreported because of limited number of patients and absence of long term follow up in most series.
      Baksi's pes anserinus transposition procedure for habitual dislocation of patella is based on sound principles and has demonstrated satisfactory results in long term.
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      The unique aspect of this procedure is the understanding that vastus medialis activity is subnormal in patellar dislocations.
      • Baksi D.
      • Pal A.
      • Baksi D.
      Electromyographic investigation of unstable patella before and after its realignment operation.
      Following an extensor realignment procedure, the muscle needs time to recover (described as ‘window period’, usually 3 months-1 year depending upon the rehabilitation protocol). There is a requirement for an active medial stabilizer to keep patella relocated till this muscle activity is restored and takes over. It is during this period, the pes anserinus transposition plays the key role of an active dynamic sling preventing patellar dislocation.
      A closer look at the procedure defines the peculiarities which makes pes anserinus transposition a success.
      • Baksi D.P.
      Restoration of dynamic stability of the patella by pes anserinus transposition. A new approach.
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      • Baksi D.
      • Pal A.
      • Baksi D.
      Electromyographic investigation of unstable patella before and after its realignment operation.
      The new attachment of the pes anserinus sling is made diagonally opposite to superolateral contractures converting it into a powerful antagonist. The tendinous insertion retains its natural elasticity and physiological strength because the neurovascular supply entering proximally is not disturbed. It is therefore far superior to artificial check reins constructed from non-vascularized severed tendons/fascias. The continuity to sartorius, gracilis and semitendinosus muscles ensures its dynamic function. When the knee is extended, the attachment is at an angle to patella, thus minimizing the overall pull. When knee is moved into flexion, the attachment gradually straightens out into direct pull acting on anteromedial aspect of patella. Thus, the sling becomes most active in knee flexed position when patella tends to be unstable. Electromyography studies have confirmed that there is preoperative weakness of vastus medialis in habitual dislocations of patella. Postoperatively, contractions of the transposed pes anserinus muscles reach a peak at 60–120° of knee flexion (the crucial stage of patellar dislocation), thereby countering instability effectively.
      One of the most dreaded issues concerning habitual dislocations is the recurrence risk. It varies in published data but described to be between 0% and 23% depending on the patient's age, procedure used, and follow-up.
      • Mittal R.
      • Balawat A.S.
      • Manhas V.
      • Roy A.
      • Singh N.K.
      Habitual patellar dislocation in children: results of surgical treatment by modified four in one technique.
      ,
      • Mittal R.
      • Sitender
      • Jain S.
      • Shukla A.
      Habitual patellar dislocation - management by two in one procedure, short term results.
      ,
      • Kraus T.
      • Lidder S.
      • Švehlík M.
      • et al.
      Patella re-alignment in children with a modified Grammont technique.
      Following Baksi's procedure, the recurrence rate described is to be as low as 6.25% for habitual dislocation cases.
      • Baksi D.P.
      Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
      These were also rectified when improper transfer of pes anserinus was revised or lateral contracture was completed. Other complications related to procedure were minimal. In our series too, the post operative period was uneventful. No recurrences were noted at mean follow up of 74.5 months. All patients were restored with complete painless range of knee motion and quadriceps strength. The mean follow up Kujala score for our patients was 97 indicating excellent knee function.
      Despite publication of detailed technique in 1981 and subsequent long term follow up in 1993, Baksi's procedure has largely remained unpracticed. Through this review, we have highlighted the biomechanical principles, key surgical steps of the procedure and the outcome expected. We have also shared our experience after Baksi's procedure for habitual dislocation of patella in children. The results were fairly predictable and we could replicate the published clinical outcomes in terms of patellar stability, no recurrences and restoration of painless full knee range of motion in challenging cases of habitual patellar dislocation. The pes anserinus transfer procedure may be revisited and considered as a viable alternative for this complex pathology.

      Funding

      There is no funding source.

      CRediT authorship contribution statement

      Anil Agarwal: study design, manuscript preparation. Ravi Jethwa: data collection, Formal analysis, manuscript preparation. Ankit Jain: Formal analysis, manuscript preparation. Jatin Raj Sareen: Formal analysis, manuscript preparation. Yogesh Patel: Formal analysis, manuscript preparation.

      Declaration of competing interest

      The authors declare that they have no conflict of interest.

      References

        • Gao G.X.
        • Lee E.H.
        • Bose K.
        Surgical management of congenital and habitual dislocation of the patella.
        J Pediatr Orthop. 1990; 10: 255-260
        • Joo S.Y.
        • Park K.B.
        • Kim B.R.
        • Park H.W.
        • Kim H.W.
        The 'four-in-one' procedure for habitual dislocation of the patella in children: early results in patients with severe generalised ligamentous laxity and aplasia of the trochlear groove.
        J Bone Joint Surg Br. 2007; 89: 1645-1649
        • Mittal R.
        • Balawat A.S.
        • Manhas V.
        • Roy A.
        • Singh N.K.
        Habitual patellar dislocation in children: results of surgical treatment by modified four in one technique.
        J Clin Orthop Trauma. 2017; 8: S82-S86
        • Mittal R.
        • Sitender
        • Jain S.
        • Shukla A.
        Habitual patellar dislocation - management by two in one procedure, short term results.
        Indian J Orthop. 2020; 55: 392-396
        • Musielak B.J.
        • Premakumaran P.
        • Janusz P.
        • Dziurda M.
        • Koch A.
        • Walczak M.
        Good outcomes of modified Grammont and Langenskiöld technique in children with habitual patellar dislocation.
        Knee Surg Sports Traumatol Arthrosc. 2021; 29: 1983-1989
        • Batra S.
        • Arora S.
        Habitual dislocation of patella: a review.
        J Clin Orthop Trauma. 2014; 5: 245-251
        • Baksi D.P.
        Restoration of dynamic stability of the patella by pes anserinus transposition. A new approach.
        J Bone Joint Surg Br. 1981; 63: 399-403
        • Baksi D.P.
        Pes anserinus transposition for patellar dislocations. Long-term follow-up results.
        J Bone Joint Surg Br. 1993; 75: 305-310
        • Baksi D.
        • Pal A.
        • Baksi D.
        Electromyographic investigation of unstable patella before and after its realignment operation.
        Indian J Orthop. 2011; 45: 69-73
        • Ittenbach R.F.
        • Huang G.
        • Barber Foss K.D.
        • Hewett T.E.
        • Myer G.D.
        Reliability and validity of the Anterior Knee Pain Scale: applications for use as an epidemiologic screener.
        PLoS One. 2016; 11e0159204
        • Kraus T.
        • Lidder S.
        • Švehlík M.
        • et al.
        Patella re-alignment in children with a modified Grammont technique.
        Acta Orthop. 2012; 83: 504-510