An 8-year-old boy was admitted in the burn unit of our hospital with the history of electrical burn injury to both of his knees when his lower limbs were entangled in a live electric wire. On examination, there was third-degree burn on both knees anteriorly with near full-thickness destruction of patellar ligament on both sides. The patient was initially managed conservatively. After multiple debridements over next 4 weeks, resultant defects on left side consisted of complete loss of patellar ligament, loss of some part of the upper end of tibia due to osteomyelitis and exposure of the joint space. On the right side also, patellar ligament was destroyed, tubercle of tibia and lower pole of patella were exposed, but the joint cavity seemed to be intact [Figure 1].
At this point of time, as both patellar ligaments were destroyed, the young boy was unable to extend his knees actively, thus he became wheelchair bound for locomotion. Hence, to give the boy an opportunity to walk, reconstruction of patellar ligament, at least on one side, became essential. For the right knee, reconstruction of patellar tendon was done with an ipsilateral and looped semitendinosus tendon graft, and for the grossly destroyed left knee joint, arthrodesis was done.
Both the joints were operated in the same sitting by two teams simultaneously. The patient was operated in supine position under general anaesthesia. On the left-sided knee joint, infected and necrotic cartilages and bone of the articular surfaces of tibia and femur were removed; the bone ends were made raw and the exposed bones were covered with ipsilateral pedicled medial gastrocnemius muscle flap with skin graft over it.
On the right side, patellar tendon was reconstructed. Incision was made at pes anserinus. Semitendinosus tendon was identified and divided at musculotendinous junction. Proximal end of the divided distal part was delivered distally at incision site keeping the insertion intact. Mid pole of the patella and the tibial tuberosity were drilled separately to make a tunnel with a cannulated burr over a K-wire. Great care was taken so as not to damage the articular surface of the patella. Thereafter, the semitendinosus tendon was passed through patella from medial to lateral side and then passed in reverse direction through the tibial tunnel and fixed to distal intact insertion of semitendinosus, thus forming a loop; the tension of the reconstructed tendon was adjusted by sutured in 30  of flexion of knee joint [Figure 2a and b]. The whole reconstruction was covered with medial gastrocnemius musculocutaneous flap.
On the left side, physiotherapy for hip and ankle joint was started on the 4th post-operative day. On the right side, knee joint was subjected to physiotherapy from 2nd week onwards; he was given passive motion training, gradually increasing the range of motion and later active movements from second post-operative week to subsequent 12 weeks. For both sides, gradual weightbearing such as standing with help was started after 6 weeks postoperatively and walking with assistance started on 8th post-operative week.
On follow-up after 10 months, the functional outcome was evaluated using Insall modification of Knee scoring (1993) system on the right side where the patellar tendon reconstruction was done. We found no flexion contracture, no pain, no extension lag, normal alignment (no varus or valgus deformity) of knee and total range of motion was 120 ; with no anteroposterior or mediolateral instability. Thus, total Knee Society score was 72 out of 100. The patient thus achieved a good range of motion of the right knee joint [Figure 3a and b] and walking without any assistance [Video 1].