Neglected Patellar Tendon Rupture treated with Semitendinosus Tendon graft: A novel technique with good result

A patellar tendon rupture must be ruled out in every patient with a knee injury. Overlooked ruptures are difficult to manage because of ligament retraction and surrounding tissue scarring. The case report by Petar Vukman et al published in ‘Cureus journal’ demonstrates that in a neglected injury, one-stage reconstruction with a single semitendinosus tendon autograft can result in a favourable outcome.

The CASE

A 23-year-old patient presented to the outpatient clinic and complained of pain in the injured leg, inability to "lock" the knee in extension, and frequent falls, especially while walking down the stairs and downhill. Seven months before the visit, he suffered a gunshot wound (GSW) to his right knee in a mass shooting.

GSW irrigation and debridement in addition to external fixation, which bypassed the knee was performed in a nearby hospital. After the postoperative radiograph was taken, external fixation was removed, the GSW was sutured, and he was discharged from the hospital.

A thorough physical exam revealed no joint effusion, a horizontal scar in the projection of the patellar tendon, a palpable gap in the tendon's midline approximately 10 mm proximal to the tibial tubercle, and proximal translation of the patella. The patient was able to actively elevate the extended leg, but with a 15° extension lag of the knee. Other clinical findings regarding ligament stability and meniscal pathology were within normal limits, with no signs of neurovascular injury or acute inflammation. The radiological examination revealed a bony fragment in a projection of the patellar tendon and patella alta, with the Insall- Salvati ratio and the Caton-Deschamps index calculated at 1.35 and 1.50, respectively. The MRI exam revealed mid- to distal intrasubstance destruction of the patellar tendon tissue

Surgical technique

A longitudinal incision was made over the earlier scar with the distal extension, exposing the tendon. Excessive scar tissue was marked and debrided along with the bone fragment. The semitendinosus tendon was identified and stripped with an open striper, leaving distal insertion intact. The muscle was removed, and the free end was whipstitched with FiberLoop. The native patellar tendon was debrided of scar tissue and stitched in the Krakow technique with no. 2 FiberWire. The patellar tendon insertion site was identified, debrided, and curetted, and the healthy bone cradle was exposed.

With the fluoroscopic control, one guide pin was placed in the projection of the tibial tubercle and the other through the midline of the patella. After the correct position was determined, tunnels were over-drilled with a 6mm reamer. The graft was pulled from medial to lateral through the tunnel, then parallel to the patellar tendon to the patellar tunnel, and then back on the medial side, parallel to the tendon to its insertion.

After reducing the patella to its height, defined with the intersection of its lower pole with the intercondylar notch roof, the graft was sutured to its insertion and surrounding soft tissue with a non-absorbable suture.

No. 2 FiberWire was used to reinsert it into the bone cradle, which was then secured together through the tunnel. The McLaughlin augmentation with 2mm FiberTape was put in through the patellar tunnel while the knee was bent at 70°. It was then secured on the side of the tibial tubercle with a PushLock anchor. Reconstruction of the surrounding soft tissue was performed using absorbable sutures. The wound was irrigated and sutured in a standard manner; the knee was placed in a tutor cast in full extension.

At the one-year follow-up, the patient walked without pain, had a full range of motion, and had enough muscle strength in the upper leg. The MRI showed the injured leg had almost the same Insall-Salvati ratio and Caton- Deschamps index as the uninjured leg.

Further reading:

Neglected Patellar Tendon Rupture Treated With a Single Semitendinosus Tendon in One-Stage Reconstruction Surgery: A Case Report of an Unusual Injury Mechanism Petar Vukman et al Cureus 17(3): e80699. DOI 10.7759/cureus.80699