Popliteal pterygium syndrome (PPS) is a congenital malformation combining craniofacial, musculoskeletal and genitourinary abnormalities [1] [2]. This rare anomaly was first described by Trélat in 1869, but the current designation was made by Grolin et al. in 1969 [2] [3] [4]. Only around 100 cases have been reported in the literature [4]. Its incidence is approximately 1 in 300,000 live births [1] [3] [5]. It is an autosomal dominant genetic disease with variable clinical expression [3] [5] [6] [7].

The main clinical manifestations of PPS are cleft lip and/or palate, fossa or sinuses of the lower lip, popliteal girdle, syndactyly, genital and toenail abnormalities [1] [5] [8]. The main most striking feature of this syndrome is the presence of a band of connective tissues extending from the ischial tuberosity to the calcaneus, forming a true web, limiting the joint mobility of the knee [7] [9]. The association of joint stiffness and retraction of posterior soft parts with cutaneous and muscular tightening poses specific therapeutic difficulties [4]. One of the most recommended procedures is the lengthening of the skin and soft tissue by excision of fibrous bands and Z-plasty at an early stage. However, full lengthening is often not achievable because the nerves and vessels at the affected site are short and displaced in the web and attached to adjacent tissues [10]. We report here the description of the first case in Guinea in a newborn corrected by the surgical method as well as a review of the literature for a diagnostic and therapeutic approach.

A 7-day-old newborn was referred to our pediatric surgery department for congenital malformation of the face and lower limbs. He is the 9^th child of a consanguineous couple aged 36 for the mother and 56 for the father. The other siblings showed no signs of deformities. The mother had performed 2CPN (prenatal consultation), no obstetric ultrasound, and had not supplemented with folic acid iron during gestation.

The baby was born at term from a eutocic vaginal delivery. His Apgar score was good. At birth he weighed 2700 g, his height was 51 cm and his head circumference was 33 cm.

On physical examination, the newborn was in good general condition, he was awake and toned. Archaic reflexes were normal. He had a temperature of 37.5˚C, a SaO₂ at 99%, a respiratory rate of 36 cycles/min and pulse of 150 beats/min. he presented a bilateral cleft lip and palate with two fossae or sinuses on the lower lip (Figure 1), bilateral popliteal pterygia assessed at 110˚ on the right side and 45˚ on the left side. He also had a triangular-shaped fold of skin extending from the base to the top of the nail in the left hallux (Figure 2), the genitourinary organs were normal in appearance. Abdominal and cardiac ultrasounds performed as part of the malformation assessment were normal. The standard radiograph of the lower limbs shows the reliefs of the fibrous band without any bone abnormalities. Doppler ultrasound of the lower limbs showed no vessels in the

fibrous band. The results of the laboratory tests were within normal limits. The surgical procedures were performed as follows. At the age of 1 month, correction of bilateral popliteal pterygia. In the lower right limb, we proceed with the excision of the fibrous band, the dissection of the sciatic nerve, the z-lengthening of the calcaneal tendon (Figure 3) and the z-skin plasty in series (Figure 4).

In the lower left limb, dissection and excision of the fibrous band followed by Z serial plasty of skin. At the end of the surgery, the lower right limb had a residual flessum limited to 20˚, that of the left had a complete extension; they were immobilized with plaster splints. Bilateral cheiloplasty was performed at the age of 3 months (Figure 5) and total palatoplasty according to Lamgenbeck at the age of 15 months by the plastic surgeon.

Lower lip sinus excision is scheduled for the next admission. The patient walked

at 16 months, the feet are plantigrade (Figure 6), he began physiotherapy with the aim of correcting the residual 20˚ flessum in the right knee.

The particularity of our case lies in the fact that the correction of the pterygia was carried out in the same operating time for both limbs. In addition we did not note a genito-urinary anomaly. With absence of syndactyly, the patient has benefited from regular follow-up, once a week for eight weeks, once a month for six months. Currently, he is reviewed every three months. At the last control, the patient walks in a plantigrade position (Figure 7).

Popliteal pterygium syndrome (PPS) is a rare congenital anomaly with autosomal dominant inheritance [3] [5] [7]. This syndrome has some features in common with Van der Woude syndrome (VWS) also inherited as an autosomal dominant condition [1] [8]. The diagnosis of PPS is clinical based on phenotypic characteristics. The main diagnostic criteria are the popliteal strap (58%), cleft lip and/or palate (93%), pits or sinuses of the lower lip (46%), syndactyly (50%), genital anomalies (37%) and nail abnormalities (33%) [8]. The patient described in our observation has the minimum criteria for the diagnosis of this syndrome.

Heterogeneous mutations in IRF6, which encodes interferon regulatory factor 6, cause the autosomal form of SPP, although there is evidence for genetic heterogeneity. An autosomal form of lethal type PPS known as Bartsocas-Papas syndrome is characterized by a more severe phenotype than that associated with the autosomal dominant form [11] [12].

The patient described in our observation should be diagnosed with PPS rather than Bartsocas-Papas syndrome.

Various hypotheses have been put forward in an attempt to explain the pathogenesis of PPS. These included a primary microvascular abnormality associated with edema leading to epithelial tissue disruption and adhesion formation, excessive epithelial growth leading to secondary mesenchymal fusion and involvement, primary collagen defect, or loss of tissue. apoptic mechanism [8] [2].

There are different methods of treating PPS. Surgical treatment is preferred because the results of conservative treatment, including casts or serial traction, have not been satisfactory [10]. Most authors agree that early correction is preferable to late correction [4] [13]. Early surgery for the popliteal webs appears to be important for long-term results.

Among the surgical treatments, the elongation of tissues such as skin, muscles and ligaments by resection of the fibrous band and Z-plasty was the most preferred technique. However, this technique is not applicable in many cases where the sciatic nerve is moved through the webbing and attached to fibrous tissue. In this case a nerve transplant is also used after stretching in the soft tissues [10]. Leonardo et al. reported a case of bilateral popliteal pterygium corrected by fibrous band excision and a stepwise Z-shaped skin plasty at 12 and 15 months of age [2]. Oppenheim et al. reported that band excision and Z-plasty was only possible in 2 of 7 patients in their series and that the rest of the cases required secondary operations such as femoral extension osteotomy, femoral shortening or amputation due to severe adhesion to the nerve [13]. The patient in our observation had bilateral popliteal pterygium, more severe on the right. It was corrected simultaneously by excision of the fibrous bands, by Z lengthening of the right calcaneal tendon and by serial Z skin plasties.

Occasionally, femoral extension osteotomy, femoral shortening or knee arthrodesis are performed concomitantly [10].

Gradual soft tissue lengthening with an Ilizarov-type external fixator may be one of the optimal procedures when fibrous band excision and z-plasty is not possible due to adhesion to the nerves or vessels of the popliteal pterygium [10]. Although correction is often easier in younger children, the ideal correction age remains difficult to define, balancing the fragility of the bone and the corrective power of the external fixator. This type of treatment is delicate and should be avoided in very young children, before the age of 3 years [4].

The correction of cleft lip and palate is done step by step from the age of 3 months when the child is in good nutritional status.

Popliteal pterygium syndrome is a rare disease, associating a spectrum of birth defects without well-defined genetic transmission. Its diagnosis is essentially clinical based on phenotypic characteristics. An early surgical treatment of the pterygium by excision of the fibrous web and a Z skin plasty in series allows a better correction of the knee flexion and ensures a better result. Correct correction of facial abnormalities makes the child look better

The management of this syndrome must be ensured by a multidisciplinary team.

The authors declare no conflicts of interest regarding the publication of this paper.

Keita, B., Toure, M.A., Sacko, M.L., Barry, M.M., Kaba, M.K. and Agbo-Panzo, D. (2022) Pterygium Popliteal Syndrome Concerning a Case in the Pediatric Surgery Department of the Donka National Hospital (Conakry CHU). Open Journal of Pediatrics, 12, 162-169. https://doi.org/10.4236/ojped.2022.121017