Congenital dislocation of the knee ranges from hyperextension of the knee to translation of the femur on the tibia. Treatment options include bracing, splinting, manipulation and casting, and surgery.
A 16-year-old girl presented with an inability to walk, stand upright, or bend her knees. She exhibited deformity of both lower extremities. She had deformed knees from birth, and they had been put in a cast for 2 months. No other therapeutic measures were taken. The patient walked on her abnormally hyperextended knees and could hyperextend the knees to 150° recurvatum. She was diagnosed with a grade III congenital dislocation of the knee, and a flexion-shortening osteotomy at the distal femur above the trochlear level was performed on her knees in 2 sessions. Postoperatively, range of motion changed from hyperextention to 80° flexion. A femoral supracondylar osteotomy was also performed 2 years later, and as a result, a 15° flexion and 15° valgus were added to the limb. The patient is now able to stand and walk without a knee brace and has 90° passive and 80° active knee flexion on both sides.
Congenital dislocation of the knee is a rare congenital disorder. The results of treatment are favorable if started before age 3 months, or sometimes before age 2 years, but there is no effective treatment for older, neglected cases; therefore, we believe this case report demonstrates a novel surgical approach.
Congenital knee dislocation was first described in 1882 by Chatelaine.1 It ranges from hyperextension of the knee to translation of the femur on the tibia.2,3 This disorder is apparent at birth and is often described by parents as a knee placed backwards.4 The prevalence is <1 in 1000 live births,5 and it can be diagnosed prenatally by ultrasound.6 It is more common in females of African descent.7
In this malformation, breech presentations are more common.8 The disorder is usually associated with other skeletal anomalies,2,3 especially when it is bilateral and associated with ligamentous laxity syndromes such as Ehlers-Danlos and Larsen syndromes, or syndromes involving multiple joint contractures such as Beals syndrome or arthrogryposis multiplex congenita.4 Ipsilateral hip dislocation and club foot are seen in 70% and 50% of these cases, respectively.3,9 Upper limb abnormalities and facial, urogenital, or gastrointestinal anomalies may also accompany congenital dislocation of the knee.4 Unilateral congenital dislocation of the knee may also occur as an isolated anomaly.4
Several etiologic factors have been proposed: relative quadriceps fibrosis, lack of formation of the suprapatellar pouch, incomplete cavitation of the patellofemoral joint,10 lack or hypoplasia of the cruciate ligaments,2 patellar hypoplasia, iliotibial tract contracture, quadriceps atrophy, fetal malposition, ligament laxity syndromes, arthrogryposis, and spinal dysraphism.
A spectrum of pathological findings exists, but the anterior capsule and the quadriceps muscle are consistently contractured. In more severe cases, intra-articular adhesions and lack of formation of the suprapatellar pouch together with displacement of the collateral ligaments, hamstring tendons, iliotibial tract, and other posterolateral/medial structures can be seen.3,9,10 Treatments include bracing, splinting, manipulation and casting, and surgical options such as quadricepsplasty, intra-articular release, and femoral shortening osteotomy.4
A review of the literature uncovered no reports describing successful treatment of a neglected case of congenital dislocation of the knee at an older age. This article presents a case of a patient with deformity of the lower extremities.
A 16-year-old girl presented with an inability to walk, stand upright, or bend her knees. She exhibited deformity of both lower extremities. Her parents reported that although her developmental milestones appeared normal, she had deformed knees from birth, and they had been put in a cast for 2 months. No other therapeutic measures were taken until age 16 years. The patient was unable to assume the normal plantigrade position in the feet and had been walking on her abnormally hyperextended knees. Her parents and relatives reported no history of skeletal abnormalities in the family.
The patient was of short stature (155 cm) with hyperextended knees and was unable to stand plantigrade. She put weight on her popliteal fossae and could hyperextend the knees to 150° recurvatum (Figure 1). Her pelvic joints appeared normal, but there were cavus, equinus, and forefoot adduction deformities in both her feet. Her face, spine, and upper extremities were normal. Her skin appeared normal, but she showed generalized ligamentous laxity based on Wynne-Davies’ criteria.11
No abnormalities were detected on neurological and urologic examinations. Pelvic radiograph was normal; however, radiographs revealed bilateral femoral condylar and patellar hypoplasia (Figure 2A) in addition to bilateral dislocation and hyperextension of the knees (Figure 2B).
The patient was diagnosed with a grade III congenital knee dislocation.4 A flexion-shortening osteotomy at the distal femur above the trochlear level was performed on her right knee (Figure 3). The distal fragment was moved 90° into flexion in the sagittal plane. After aligning the lower limb in the coronal plane, the fragment was fixed to the shaft of the femur using a 95° condylar blade plate. Following fixation, range of motion (ROM) changed from hyperextention to 80° flexion. Subsequently, an Achilles tendon lengthening was performed to correct the patient's equinus, and the lower limb was placed in a long leg cast.
Within 1 month postoperatively, the patient was able to put weight on the right lower extremity using a walking frame. Four months postoperatively, her left knee was surgically corrected in the same manner as her right knee. One month after the second operation, the patient was able to bear weight fully on the right side and partially (with the aid of a walker) on the left side. She had a course of physiotherapy to improve ROM.
Seven months after the first operation (3 months after the second), flexion in the knees (originally only 0°-5°) reached 30° on the right and 20° on the left side. Only 15° of hyperextension remained in the knees. Range of motion continued to increase with the use of a continuous passive motion machine over the next 2 months to 70° on both sides. Muscle strength in the quadriceps, hamstrings, flexors, extensors, and abductors of the hip was increased so that the patient was able to stand and walk with only a knee immobilizer and minimal limping.
Approximately 2 years after her first operation, the patient was able to stand without a knee brace and had 90° passive and 80° active knee flexion on both sides and only 10° of hyperextension. Physical findings on examination of the knees included a positive Lachman's test, especially on the left side; 15° of varus on the right side and 10° of valgus deformity on the left side; and a positive anterior drawer test on both knees. Interestingly, a firm endpoint was felt on stress test of both knees.
Three years postoperatively, due to varus and recurvatum of the right inferior limb (Figure 4), a femoral supracondylar osteotomy was performed on the patient. As a result, 15° of flexion and 15° of valgus was added to the limb (Figure 5). Figure 6 shows the latest postoperative photograph of the patient in a standing position.
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Figure 4: Postoperative radiograph showing both knees at 2 years. Figure 5: Radiograph showing a femoral supracondylar osteotomy of the right knee and adding 15° of flexion and 15° of valgus 2 years after the last operation. Figure 6: Latest postoperative photograph of the patient in the standing position.
Congenital dislocation of the knee is a rare disorder. It is usually associated with other skeletal disorders and syndromes2,3; therefore, patients need to be thoroughly examined, especially when the dislocation is bilateral. However, it may also be an isolated deformity.4 Congenital dislocation of the knee is classified in 3 grades. In grade I, the knee will flex and reduce with gentle stretching of the quadriceps. In grade II, the knee will not flex beyond natural, but the femoral and tibial epiphyses are in contact and do not subluxate when flexion is attempted. In grade III, knee flexion is not possible and the tibia, which is anteriorly translated in the resting position, displaces laterally on the femur when more vigorous flexion is attempted.4
In our patient, there was no positive family history, and the only outstanding associated problem was generalized ligamentous laxity; no specific syndrome, such as Ehlers-Danlos or arthrogryposis, was diagnosed. Nonsurgical treatment is favored in the early stages of congenital dislocation of the knee. According to Ferris and Aichroth,8 the results of treatment are favorable if started before age 3 months. In cases presenting after age 6 months, surgery is usually considered before age 1 year,9,12 although good results have been achieved even in patients operated on before age 2 years.8
The recommended surgical procedure is a V-Y quadricepsplasty, with medial/lateral arthrotomy to mobilize the anteriorly displaced ligaments. Anterior cruciate ligament (ACL) deficiency and posterior capsule redundancy are considered less important at this stage.4 The same surgical procedures are recommended for older patients.13
Herring4 recommends femoral shortening, ACL reconstruction, and posterior capsulorrhaphy for patients with congenital dislocation of the knee and ligament laxity, citing complications of quadricepsplasty (including weakness of the quadriceps) followed by extension lag and fibrosis resulting in lack of flexion, and also the presence of posterior capsular redundancy and lack of ACL, which may result in recurrent anterior knee dislocation. Along with the osteotomy, it is possible to correct the accompanying developmental dysplasia of the hip. In our patient, we felt there was no need for quadriceps lengthening with the flexion osteotomy; however, extra-articular correction of the distal extension deformity gave some stability to the knee.
Considering that in our patient no intra-articular ligament release was performed, the reason for instability must be sought in geometric differences in the shape of femoral and tibial condyles. According to Ferris and Aichroth,8 anteroposterior instability may be investigated by arthroscopy and evaluation of the cruciate ligaments. Congenital dislocation of the knee is a rare disorder with no effective treatment for neglected cases.
- Shattock SG. Genu recurvatum in a foetus at term. Trans Pathol Soc London. 1891; (42):280-292.
- Katz MP, Grogono BJ, Soper KC. The etiology and treatment of congenital dislocation of the knee. J Bone Joint Surg Br. 1967; 49(1):112-120.
- Johnson E, Audell R, Oppenheim WL. Congenital dislocation of the knee. J Pediatr Orthop. 1987; 7(2): 194-200.
- Herring JA. Disorders of the knee. In: Herring JA, ed. Tachdjian’s Pediatric Orthopaedics. 4th ed. Philadelphia, PA: Saunders/Elsevier; 2008:919-926.
- Charif P, Reichelderfer TE. Genu recurvatum congenitum in the newborn: its incidence, course, treatment, prognosis. Clin Pediatr (Phila). 1965; 4(10):587-594.
- Elchalal U, Ben Itzhak I, Ben-Meir G, Zalel Y. Antenatal diagnosis of congenital dislocation of the knee: a case report. Am J Perinatol. 1993; 10(3):194-196.
- Ahmadi B, Shahriaree H, Silver CM. Severe congenital genu recurvatum. Case report. J Bone Joint Surg Am. 1979; 61(4):622-623.
- Ferris B, Aichroth P. The treatment of congenital knee dislocation. A review of nineteen knees. Clin Orthop Relat Res. 1987; (216):135-140.
- Bensahel H, Dal Monte A, Hjelmstedt A, et al. Congenital dislocation of the knee. J Pediatr Orthop. 1989; 9(2):174-177.
- Curtis BH, Fisher RL. Congenital hyperextension with anterior subluxation of the knee. Surgical treatment and long-term observations. J Bone Joint Surg Am. 1969; 51(2):255-269.
- Wynne-Davies R. Acetabular dysplasia and familial joint laxity: two etiological factors in congenital dislocation of the hip. A review of 589 patients and their families. J Bone Joint Surg Br. 1970; 52(4):704-16.
- Bell MJ, Atkins RM, Sharrard WJ. Irreducible congenital dislocation of the knee. Aetiology and management. J Bone Joint Surg Br. 1987; 69(3):403-406.
- Ooishi T, Sugioka Y, Matsumoto S, Fujii T. Congenital dislocation of the knee. Its pathologic features and treatment. Clin Orthop Relat Res. 1993; (287):187-192.
Drs Kazemi, Seyyed Hosseinzadeh, Eajazi, and Daftari Besheli are from Akhtar Orthopaedic Research Center, Akhtar Orthopaedic Hospital, and Drs Abbasian and Farhang Zanganeh are from Akhtar Orthopaedic Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Drs Kazemi, Abbasian, Seyyed Hosseinzadeh, Farhang Zanganeh, Eajazi, and Daftari Besheli have no relevant financial relationships to disclose.
Correspondence should be addressed to: Mohammad Reza Abbasian, MD, Akhtar Orthopaedic Hospital Research Center, Elahieh, Tehran, Iran (firstname.lastname@example.org).