Open, combat-related loss, or disruption of the knee extensor mechanism: treatment strategies, classification, and outcomes

Multifocal Disruption of the Extensor Mechanism of the Knee: A Case Report

CASE

A 41-year-old man presented with a transverse patella fracture and proximal patellar tendon avulsion after a fall from standing. Disruption of the extensor mechanism of the knee at multiple points is rare. He was treated operatively for his patella fracture and patellar tendon avulsion but experienced early failure of the patellar tendon fixation requiring reoperation. Both components of injury ultimately healed, and he returned to function.

CONCLUSION

This case describes a rare presentation of an uncommon injury pattern affecting the extensor mechanism. This is the first report to describe multifocal failure of the extensor chain from a low-energy mechanism.

Complete Traumatic Trifocal Failure of the Extensor Mechanism of the Knee: A Case Report and Review of the Literature

The unique case of a rare 3-level extensor mechanism failure in a 28-year-old male, involving a tibial tubercle avulsion fracture, a patellar tendon avulsion off the tibial tubercle fragment, and a severely comminuted patella fracture, and the surgical technique required to repair such an injury is presented. Focus is spent on the unique repair of a tendon injury when both proximal and distal bony attachments are damaged. Trifocal knee extensor mechanism is a rare clinical entity with minimal literature available—to date, this injury has only been reported in a retrospective review of combat-related injuries in military personnel. It is important to maintain an understanding of knee extensor mechanism anatomy and perform thorough investigation of high-energy knee injuries to ensure adequate treatment of all injuries. The outcome presented in this case shows that positive results after complex extensor mechanism injuries may be achieved, but limited data exists to elucidate optimum treatment. It is essential for surgeons to have firm grasp of techniques used to treat each segment of the extensor mechanism so that they may be combined when a patient presents with complex, multifocal injury.

Medial Gastrocnemius Flap for Reconstruction of the Extensor Mechanism of the Knee Following High-Energy Trauma. A minimum 5 year follow-up

INTRODUCTION

The purpose of this study was to assess the medium-term results of reconstruction of the extensor mechanism using the medial gastrocnemius while also providing soft tissue coverage.

MATERIALS AND METHODS

This retrospective review consisted of a consecutive series of four patients (age 28-40 years) with complex high energy traumatic injuries to lower extremity including both soft tissue loss and disruption of the knee extensor mechanism. The medial gastrocnemius rotational flap was used to reconstruct the patellar tendon and restore soft tissue coverage simultaneously. Range of motion and extensor lag; functional recovery was judged by return to work and sports activity. Validated measures included the Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, and the modified Cincinnati Score.

RESULTS

At the final follow up was 61.5 (57-66) months after reconstruction, the mean SF 12 physical component score ranged from 21.7 to 56.8 with a median of 55.3; the mental component from 42.8 to 60.7 with a median of 58.6. The KSS knee score ranged from 50 to 78 with a median of 68; the function score from 65 to 90 with a median of 85. The Oxford knee score ranged from 22 to 45 with a median of 33.5. The KOOS ranged from 28 to 82.7 with a median of 73.7 and the modified Cincinnati score from 38 to 82 with a median of 76.5. Knee range of motion ranged from 0 to 120°. Of the four patients three returned to working fulltime in their profession and returned to sports, including mountain biking and fitness training.

CONCLUSIONS

For severe traumatic knee injuries with the combination of soft tissue defects and disruption of the extensor mechanism, the medial gastrocnemius flap provides an excellent reconstructive option to address both problems simultaneously. The results of this small case series support the use of this limb salvage technique.