Congenital dislocation of the knee is a condition characterised by hyperextension deformity of knee with varying degrees of pathological anterior displacement of the tibia present at birth.
- First described by Chenssier in 1812.
- Subsequently reported by Chatelaine in 1822 and by Bord in 1834.
- Three theories have been proposed about the causation. (Elmadag 2013)
- Mechanical theory – Due to abnormal intrauterine position
- Primary embryologic theory – Due to embryonic defect
- Mesenchymal theory – Due to quadriceps contracture
- The primary cause can be extrinsic or intrinsic.
- Intrinsic causes are genetic or developmental and extrinsic factors are mechanical factors.
- Extrinsic causes can be oligohydramnios, multiple pregnancy, intrauterine fetal malposition, quadriceps contracture and birth trauma.
- Majority of cases are sporadic.
- Incidence is 1 in 100,000 live births. Seen in 1% of patients with DDH
- Breech presentation – 30%
- CTEV- 47%
- DDH- 50%
- Arthrogryposis multiplex
- Larsen syndrome
- Ehlers Danlos syndrome
- Beals syndrome
Leveuf and Pais Classification
Simple hyperextension – 15-200hyperextension, passive flexion up to 900.
Anterior subluxation – 25-400hyperextension and no flexion.
Anterior dislocation – No contact between distal femoral and proximal tibial articular surfaces.
Finder’s Classification (Finder 1964)
Type I– Physiological hyperextension up to 200is considered normal. Usually disappears by the age of 8 years.
Type 2- Simple hyperextension that persist into adult life.
Type 3- Anterior subluxation with hyperextension up to 900. Flexion only to neutral position.
Type 4- Dislocation of knee with anterior and proximal migration of proximal tibia.
Type 5- Complex variants associated with syndromes and other congenital deformities.
Tarek CDK grading system (Tarek 2011)
G1- Simple recurvatum. Passive flexion >900. Manage by serial casting.
G2- Subluxation. Passive flexion 30-900. Manage by percutaneous quadriceps release
G3- Dislocation. Passive flexion <300. Manage by V-Y Quadricepsplasty.
- Quadriceps fibrosis and contracture.
- Tight anterior capsule.
- Hypoplastic or absent patella.
- Hypoplastic suprapatellar bursa.
- Anterior subluxation or dislocation of knee.
- Transverse anterior skin crease.
- Round condyles.
- Increased tibial plateau.
- Rotatory or valgus deformity of tibia.
- Hamstrings may be displaced anteriorly and become extensors of knee.
- Absent or elongated anterior cruciate ligaments (Katz 1967).
- Lax or displaced cruciate ligaments.
- Child born with varying degrees of hyperextension deformity of the knee.
- Passive flexion of knee limited to varying degrees depending on the severity.
- May be associated with other musculoskeletal anomalies like developmental dysplasia of hip or congenital talipes equinovarus.
- Varying degrees of anterior displacement of the tibia in relation to the femur present.
- Prenatal ultrasound may help in diagnosis.
- X-ray shows deformity with angulation in hyperextension type, anterior translation with variable amount of contact between femur and tibia in subluxation type and total loss of contact between femur and tibia with hyperextension deformity in dislocation type.
- Ultrasound shows obliteration of suprapatellar pouch.
- Arthrogram may be necessary to identify intra-articular pathology.
- Treatment options
- Closed manipulative reduction and serial casting
- Percutaneous quadriceps recession
- V-Y quadricepsplasty
- Treatment should be started as early as possible, preferably within 24 hours.
- Rumiantcev closed reduction method
- Give longitudinal traction to the knee by holding the foot and ankle and by applying counterpressure over the hip for about 20 minutes.
- Flex the hip fully, so that the back of the knee is accessible to the surgeon.
- Place the thumbs of the surgeon on the posterior aspect of femoral condyles
- Place the index fingers on the anterior aspect of tibia.
- Apply pressure to reduce the anterior displacement and flex the knee.
- Immobilize in the position of maximum flexion achieved.
- Repeat the procedure weekly till 900flexion is achieved.
- Ko closed reduction method
- To be used when patient is seen early, preferably within 24 hours of birth.
- Gentle persistent manual traction.
- Apply anteriorly directed force on the distal femur and posteriorly directed force on the proximal tibia
- Flex the knee, reduction is achieved when knee is flexed more than 900.
- Immobilize in >900flexion using a dorsal long leg splint or cast.
- Change the casting every 2 weeks for a 6-8 week period.
- Follow up done every 2 months till walking age, then annually.
- Radiographs taken every 4 months during the first one year, then annually.
- In 19 infants with 25 CDKs treated within 24 hours of birth, Chun-Chien Cheng (2010) was able to achieve successful closed reduction by closed manipulation lasting under 5 minutes if done within 8 hours of birth. More than 20 minutes was needed, when reduction was done 20 hours after birth. There was only one failure to achieve reduction.
- Surgical intervention is indicated if nonoperative treatment is not successful by 3 months.
- Need for surgical intervention ranges from 4% to 58% in the literature.
- Outcomes are most favorable if surgery is done within 2 years of age.
- Treatment guidelines as per Tarek CDK grades.
- Type 1
- Serial casting
- Type 2
- Serial casting with or without skin traction. Once 900flexion is achieved, Pavlik harness. If 900flexion cannot be achieved by 4 weekly casts, do percutaneous quadriceps release.
- Type 3
- Percutaneous or mini-open quadriceps or patellar tendon release
- Open reduction with quadriceps lengthening, release of anterior capsule, release of iliotibial band and hamstrings and the capsulorrhaphy of the posterolateral and posteromedial capsules.
- Femoral shortening
- Type 1
- Treatment of associated deformities
- Percutaneous quadriceps release first is advised if treatment is started after one month.
- Rumiantcev treatment protocol – 4 Stages
- Stage 1
- Closed reduction by manipulation in the above mentioned method. If successful and more than 900flexion is achieved, then immobilize in flexion for 7-10 days in a cylinder cast. If not successful, proceed to stage 2.
- Stage 2
- Immobilize in the achieved degree of flexion by cylinder cast. Repeat the manipulation every 2-4 days till full reduction is achieved by 2-4 weeks. Monitor reduction after each manipulation by clinical examination and ultrasound to detect false correction. If correction is false, proceed to stage 3.
- Stage 3
- Do percutaneous quadriceps tenotomy, followed by serial manipulation and casting. If not successful, proceed to stage 4.
- Stage 4
- V-Y quadricepsplasty with anterior capsular release.
- 81% of patients did not need surgery in their series of 50 CDK in 37 patients.
- Tenotomy was needed in 7 of 37 patients and was successful in 4 of 7 patients.
- V-Y quadricepsplasty needed in the remaining 3 patients.
- Stage 1
- Open reduction associated with quadriceps insufficiency
- Percutaneous quadriceps release (Roy & Crawford technique)
- Assistant holds the knee in maximum possible flexion.
- Make a stab incision one to two patellar lengths superior to the patella
- Release the fascia over the rectus femoris.
- Make medial and lateral stab incisions at the level of superior pole of patella to release the medial and lateral quadriceps and the retinaculum.
- Flex the knee to 900 flexion and immobilise in more than 900 flexion in bilateral long leg cast with spreader bar or a hip spica for 6 weeks.
- Then start physiotherapy. If there is associated developmental dysplasia of hip, then give Pavlik harness for another 6 weeks.
- If 900 flexion cannot be achieved after percutaneous tenotomy then open V-Y quadricepsplasty is indicated.
- V-Y Quadricepsplasty (Curtis & Fischer technique)
- Make a long anterior incision starting superomedially and ending inferolaterally
- Incision extends from the level of lesser trochanter to the tibial tuberosity.
- Identify and dissect the interval between the rectus femoris and the vastus medialis and the vastus lateralis.
- Incise the central quadriceps in such a way that allows V-Y plasty.
- Release the iliotibial band if required.
- Release the anterior capsule of the knee transversely from the medial collateral ligament to the lateral collateral ligament.
- Once the knee can be flexed to 900, repair the quadriceps.
- Quadriceps repaired in 450 flexion of knee.
- Apply Tarek-Shady plaster of Paris cast.
- 2 slabs
- One anterior groin to toe slab
- Other slab around the thigh and leg transversely, holding the knee in 900 flexion.
- POP avoided in the popliteal fossa.
- Prognosis depends on the following factors.
- Associated anomalies indicate worse outcome.
- Associated syndromes indicate worse outcome.
- Delay in treatment worsens the outcome. (Laurence 1967)
Outcome assessed by using Seringe Criteria
- Oetgen (2010) found that 78% of knees were having instability.
- Rumiantcev found that if treatment was started on day 1 after birth, the extensive surgery was needed only in 5% and if started after 2 days, 17% required extensive surgery.
- Elmadağ Mehmet, Ceylan Hasan Huseyin, Erdil Mehmet, Imren Yunus, Bilsel Kerem, Tuncay Ibrahim. Congenital Dislocation of Knee. Eur J Gen Med 2013;10(3):164–166. DOI: https://doi.org/10.29333/ejgm/82252.
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