*Corresponding author: Yasir Salam Siddiqui
Mailing address: Department of Orthopaedic Surgery, Faculty of Medicine, J. N. Medical College, A.M.U., Aligarh 202002, India.
Email: yassu98@gmail.com

Received: 11 December 2020 / Accepted: 12 January 2021
DOI: 10.31491/CSRC.2021.03.071

A one-and-a-half-year-old male baby was brought to us by his parents with complaints of restriction of movements of the right elbow with polydactyly, giving an unacceptable cosmetic appearance of the forearm and hand. They further added that the child is also having difficulty in holding the objects. The patient was their third child with two female siblings without any such complaints. There was no history of consanguinity. The baby was full term, delivered through the vaginal route. There was no history suggestive of any maternal infection or any exposure to teratogenic agents throughout the antenatal period. There was no family history of the congenital elbow and hand anomalies in first degree lineages. There was no developmental delay. No history of any other joint involvement or other systemic illness. Clinical examination revealed shortening of the right forearm with fixed flexion deformity of 20 degrees at the elbow, with a further 50 degrees of free flexion possible (range of motion = 20 to 70 degrees). Forearm rotations were grossly restricted. The wrist was deviated radially with the hand having six well-formed fingers in a single plane (Figure 1). Contour and the movements of the right shoulder were comparable to the left shoulder. The child was able to hold the objects in between fingers (crude grasp). However fine grasp requiring opposition function was not conceivable. The left upper extremity was absolutely normal. There were no other skeletal abnormalities. Furthermore, no definite syndromic features were noted. Systemic examination was unremarkable. Ultrasonography of the abdomen and echocardiography were normal. The radiographic anatomical features of our patient as seen in Figure 2 and 3 could be summarized as follows：
(1) A normal humerus with an ossification center in the post-axial part of the distal epiphysis;
(2) Thumb and radius was absent;
(3) Two ulnae facing each other: post-axial ulna had a proper morphology and pre-axial ulna was shorter with less defined proximal anatomical features;
(4) Wrist shows duplication of ossification centers corresponding to lunate;
(5) Normal morphology of metacarpals and phalanges of three post-axial fingers;
(6) Hypoplasia of all pre-axial metacarpals;
(7) Shortening of all phalanges of the pre-axial index finger;
(8) Normal pre-axial middle (M) and ring (R) fingers;
(9) Hypoplasia of pre-axial little (L) finger.
The wrist and hand showed two carpal bones and six metacarpals all lying in the same plane compared to the normal left hand (Figure 2 and 3). The two carpal bones were centered over the medially placed ulna. In the present circumstance, we planned for staged surgeries, with an objective to provide a functional range of motion at the elbow, forearm rotations, and reconstruction of the thumb for oppositional grasp. Meanwhile, the patient was put on stretching exercises of elbow, wrist and fingers, especially to correct the radial deviation of the wrist along with night splinting of the wrist in a neutral position. Parents were communicated about the need for regular follow-up for proper treatment and rehabilitation of the child, least as the child would grow there will be limitations of activities which require coordinated movement of the elbow, forearm, and hand-like writing, buttoning, unbuttoning, tying shoelaces and others. However, the parents never turned up again after their first visit, highlighting the neglect of the deformity.

Our patient had double ulnae in the right forearm with six digits with six corresponding metacarpals in a single plane with two carpal bones supported by a medially placed ulna. Laterally placed hypoplastic ulna was not supporting any of the carpal bones. This might be due to a delay in the development of the ossification centers on the lateral side. Both thumb and radius were absent. Although the laterally placed ulna was hypoplastic in comparison to the medial one, both ulnae were well molded. Our case was classified as type I ulnar dimelia, according to Al‑Qattan et al classification ^[2].
Ulnar dimelia is probably due to the failure of differentiation of a part of the ray rather than its pure duplication ^[18]. During the embryogenesis, a disturbance of differentiation of Zone of Polarizing Activity (ZPA) along the axis of the limb may lead to post-axial duplication and ulnar dimelia ^[3]. Few authors have reported HOX genes mutations or translocation breakpoint at 14q13 as the genetic mechanisms of ulnar-dimelia ^{[19, 20]}.
A classical ulnar dimelia has symmetrical distribution around the midline axis. However, the non-classical one lacks symmetrical distribution in morphogenesis of the forearm bones and the fingers ^[8]. In the nonclassical one, the forearm may contain an ulna and a radius, or even three bones in different combinations ^[9-11]. Even though seven ^{[9, 10]} or eight ^{[2, 10-14]} digits are typical, patients with six ^{[15, 16]} or even five digits ^[17] have been described in the literature. Taking into account the bony morphology of the forearm, Al-Qattan et al published a descriptive classification for the ulnar dimelia ^[2]. The goal of the management of such a condition is to achieve a functional and cosmetically acceptable upper extremity by executing single-stage or more often multiple-stage operations. The literature designates, depending upon the severity of the functional and cosmetic deformity, the management of this condition varies from physiotherapy alone to multiplestage operations ^{[1, 2, 7, 8, 11, 18]}. The best age for the reconstruction of hand is before the second year ^[11]. Surgery is preceded by passive range of motion exercises and choosing the appropriate radial digit for pollicising. Hand deformities can be corrected to give a satisfactory outcome when they are not so severe. Either index or middle finger can be pollicised depending upon the type of ulnar dimelia. When deformity correction is not feasible the goal is to achieve the hold function of the hand. Good functional and cosmetic results have been reported in a few studies ^[3]. The thenar reconstruction by interosseous muscle transfers and further improvements can be achieved by tendon transfer at a later date has also been described in the literature ^[21]. The function of the wrist, forearm, and elbow may improve with arthroplasty of the affected joints ^[22].
In the present case study, we discussed with the parents about the future prospects and limitations of activities due to deformity and planned for staged surgeries with an objective to provide functional and cosmetically acceptable upper extremity. However, the parents never turned up again with the patient for taking treatment, highlighting the neglect of the deformity. The neglect was probably due to the low socioeconomic status and ignorance of parents. We believe that in the patient described above, excision of the proximal end of the laterally placed ulna with soft tissue reconstruction along the medially placed ulna and pollicization would have given a reasonable functional and cosmetic enhancement of the upper extremity.