(ii) The “floating knee” in adults and children

Bilateral floating knee injury in a child with down syndrome: A case report

INTRODUCTION AND IMPORTANCE

Floating knee injury is a rare injury that involves a simultaneous fracture of the femur and tibia. It is more common among young men and is generally caused by high-speed blows. Down syndrome is a chromosomal disorder associated with various musculoskeletal conditions. Children with Down syndrome have generalized ligamentous laxity, joint hypermobility, and hypotonia, leading to musculoskeletal conditions such as atlantoaxial instability, hip instability, and patellar instability.

CASE PRESENTATION

A 10-year-old boy with Down syndrome was admitted to the emergency room due to a car accident. Radiographic examinations revealed a diaphyseal fracture of the right femur and a diaphyseal open fracture of the tibia compatible with floating knee injury Type-D, and a physeal fracture of the distal femur (Salter-Harris type 2) and a metaphyseal fracture of the proximal tibia compatible with floating knee injury Type-C. The patient underwent preoperative investigations, including a neck radiograph, cardiology evaluation, pulmonary assessment, and hematologic check. The patient underwent surgery to fix all fractures.

CLINICAL DISCUSSION

The necessary investigations were carried out to perform anesthesia and measures before, during, and after the operation. Down syndrome may help the patient recover, especially the ROM, due to various musculoskeletal conditions, such as generalized ligamentous laxity, joint hypermobility, and hypotonia.

CONCLUSION

Children with Down syndrome may have various musculoskeletal conditions that can complicate the treatment of other injuries such as floating knee injury. Preoperative investigations should be performed to identify any potential complications.

Variables affecting functional outcome in floating knee injuries

BACKGROUND

The surgical outcome of floating knee injuries is difficult to predict. The high-velocity nature of the injury, complex fracture pattern and associated soft tissue/visceral injuries may have some impact on the functional outcome. The present study evaluates the variables affecting the clinical and radiological outcomes of floating knee injuries.

MATERIALS AND METHODS

The clinical, radiological and functional outcome (Karlstrom and Olegrud criteria) of 89 patients with 90 floating knee injuries were evaluated at the end of one year who were managed in our level 1 trauma center between January 2013 and December 2016. The details of the injury, fracture pattern, management and complications were collected retrospectively from their records.

RESULTS

There were 81 (91.1%) males and 8 (8.9%) females with mean age of 34.34 ± 12.28 years. The mean time for tibia and femur union was 9.52 (±6.6) and 10.5 (±7.37) months. There was significant delay (p < 0.005) in time taken for union in segmental femur fractures (14.3 ± 9.6 months) compared to nonsegmental femur fractures (8.68 ± 5.18 months). Such significant difference in time taken for union was not seen in tibial segmental (10.6 ± 4.62 months) and nonsegmental fractures (9.05 ± 7.27 months). As per the Karlstrom and Olegrud criteria, there were 22 (24.4%) excellent, 26 (28.9%) good, 24 (26.7%) fair and 11 (12.2%) poor outcome. There were 15 patients with malunited tibia, 6 with malunited femur, 10 with limb length discrepancy and 39 with knee stiffness. 28 (33.3%) patients underwent major additional procedures such as bone grafting, re-fixation or bone transport or tendon transfer. It was observed that open tibia fracture, segmental fracture, intra-articular fracture, additional surgical procedures, initial external-fixator (ex-fix) application were significantly associated with development of knee stiffness, limb shortening, malalignment and unsatisfactory (Karlstrom and Olegrud fair to poor) functional outcome.

CONCLUSION

Open tibial fractures, segmental fractures, intraarticular involvement, additional surgical procedures and initial external fixator application are the poor prognostic indicators of floating knee injuries.

Floating knee: a modified Fraser's classification and the results of a series of 28 cases

AIM

This work aims to design a modified Fraser's classification and report the clinical outcomes of a series of 28 floating knees.

METHODS

Between January 2006 and December 2009, 31 consecutive patients with 31 floating knees were treated at the Affiliated Hospital of Nantong University. In total, 28 cases were available for analysis. The floating knees were classified based on a modified Fraser's classification. Twelve cases were temporarily stabilised by an external fixator. Definitive fixation was performed for tibia and femur fractures using either nailing or plating. Functional outcomes were assessed according to the criteria established by Kalstrom and Olerud. The patients were followed up for a mean of 29 months (range, 12-60 months).

RESULTS

The floating knees were classified as three types: type I, extra-articular fracture; type II, articular surface involved; and type III, patella involved. Type II injuries were subdivided into type IIA injury (articular simple) and type IIB injury (articular complex). According to the modified classification, there were 11 cases of type I, 2 cases of type IIA, 8 cases of type IIB and 7 cases of type III injury. Complications were found in seven cases, including three cases of infection, two cases of knee instability and two cases of knee stiffness. The functional outcomes were 7 excellent, 13 good, 5 acceptable and 3 poor. The excellent or good rate was 91% (10/11) in type I, 100% (2/2) in type IIA, 63% (5/8) in type IIB and 43% (3/7) in type III injuries.

CONCLUSION

The modified Fraser's classification provides a more reliable basis for surgeons to monitor results and compare treatment results with other surgeons. According to the modified classification, the results of type IIA injury appeared to be comparable to those of type I injury. Type IIB and type III injuries represent the fracture types with the worst prognosis.

Challenges in the management of floating knee injuries in a resource constrained setting

Floating knee injuries pose major challenges in management. There is little information on the patterns of these injuries and the challenges of managing them in our setting. Patients with floating knee injuries who were seen and treated over a 5-year period at our center were retrospectively reviewed. The patterns of the injuries, associated injuries, methods of management and factors that influenced the outcome were analyzed. Twenty-five patients, consisting of 19 males and 6 females with a mean age of 33.4 ± 16.04 years, satisfied the study criteria. All were caused by road traffic injuries, motor cycle crashes accounting for 19 (76%). Twenty-two (88%) injuries were Blake and McBryde type 1, while 3 (12%) were of type 2A. Thirty-two percent of the patients had surgical fixation of both fractures, while 40% of the patients had both fractures managed non-operatively. Non-operative management strongly correlated with development of malunion. The results of management of floating injuries in our setting are not satisfactory. Orthopedic and trauma care should be made accessible to those requiring it.