ISOLATED AVULSION FRACTURE OF THE HEAD OF THE FIBULA IZOLOVAN AVULZIONI PRELOM GLAVE LISNJAČE

Introduction. Rupture of lateral collateral ligament of the knee is most often joined with other ligament ruptures. Isolated rupture of this ligament is rare and there are few papers about treatment options and results. Here we reported a case of isolated lateral collateral ligament rupture and the treatment outcome. Case report. A patient, 22 years old male, injured his left knee while playing American football. While landing on the outstretched left leg, he felt a sudden pain in his knee. The patient could not continue the competition. Initial orthopedic examination revealed lateral opening and further diagnostic procedure (magnetic resonance imaging) revealed isolated grade III rupture of lateral collateral ligament with avulsion fracture of the fibular head, and distension of anterior and posterior cruciate ligaments. Patient was surgically treated with metal sutures passed through conjoined tendon and proximal fibula. Postoperatively patient worn above knee cast for 6 weeks and after that he was included in rehabilitation. Three and six years after this injury, the patient has still been professional football player with no symptoms and no clinical instability of the knee despite radiological and computed tomography verified pseudoarthrosis of the fractured fibular head fragment. Conclusion. Early diagnostic and absence of additional injuries of the knee leads to a faster and full functional recovery of patients with isolated avulsion fracture of the fibular head, while surgical treatment provides knee stability with no residual ligament instability during sports activities.


ABSTRACT
Introduction.Rupture of lateral collateral ligament of the knee is most often joined with other ligament ruptures.But isolated rupture of this ligament is rare and there are few papers about treatment options and results.Here we are presenting acase of isolated lateral collateral ligament rupture and out way or treatment.Case report.Patient 22 years old, injured his left knee while playing American football.While landing on the outstretched left leg he felt a sudden pain in his knee.He could not continue the competition.Initial orthopedic examination reveals lateral opening and further diagnostic (magnetic resonance imaging) revealed isolated grade III rupture of lateral collateral ligament with avulsion fracture of fibular head,and distension of anterior and posterior cruciate ligaments.Patient was treated operatively with metal sutures passed through conjoined tendon and proximal fibula.Postoperatively patient worn above knee cast for 6 weeks and after that he was included in rehabilitation.Three and six years after this injury he is still professional football player with no symptoms and no clinical instability of the knee despite radiological and computerized tomography (CT) verified pseudoarthrosis of fractured fibular head fragment.Conclusion.Early diagnostic and absence of additional injuries of the knee leads to faster and full functional recovery of these patients with no residual ligament instability during sports activities.

Introduction
The fibular collateral ligament (FCL) is the primary varus stabilizer of the knee , and its injuries are frequently associated with anterior cruciate ligament (ACL), posterior cruciate ligament (PCL) and posterolateral corner injuries.Isolated grade III tears of the lateral collateral ligament (LCL) with avulsion fracture of the head of the fibula are rare and these fractures has been called the "arcuate" sign.The "arcuate" sign is used to an avulsed fragment related to the insertion site of the arcuate complex, which consists of the fabello-fibular, popliteo-fibular, and arcuate ligaments.
Although avulsion fracture of the head of the fibula associated with ACL, PCL and posterolateral corner injuries, is well describedand primary repair has been recommended,,,,,,4, limited data exist in the literature on surgery technique and clinical results,,.
The purpose of this paper is to investigate result of surgical treatment of patient with isolated grade III LCL injury with avulsion fracture of the head of the fibula.

Case report
Patient 22 years old, injured his left knee while playing American football.While landing on the outstretched left leg he felt a sudden pain in his knee.He could not continue the competition.In the emergency room, orthopedic surgeon noted the lateral opening of the knee during varus stress test.Lachman test could not be performed due to pain.Neurocirculatory status of leg was normal.Four days later patient didmagnetic resonance imaging (MRI) of his left knee revealing a distension of ACL and PCL (Fig 1  Seven days after the injury patient was admitted to hospital, and after four days more he wasoperated.In the operating room, Lachman test was performed under general anesthesia and has showed firm end point.Anterior and posterior driver's tests were negative, and varus stress test at 0 and 30 degreesof knee flexion were positive.After placinga tourniquet, a slightly curved skin incision was made on the lateral side of the knee from fibular neck to the level of lateral femoral epicondyle, and the fibular nerve was identified.Common attachment of biceps tendon and LCL to the dislocated fibular head fragment was prepared, and metal suture was passed through.One drill hole was placed through proximal fibula, 1 cm distal to the fracture level and the wire was pulled through this hole.After anatomic reposition of the fibular head fragment,the cerclage was tied with the knee in 30 degrees of flexion and neutral rotation.The tourniquet was deflatedand bleeding was controlled.The wound was closed in layers with interrupted sutures.
The above-the-knee plaster cast was applied.Six week later full weightbearing was allowed and physical therapy started.Six months after the injury, the patient was back to preinjury sports activity level.
On the follow-up 3 and 6 years later the patient was still professional American football player.He had full range of motion, no pain and no swelling.Lachman test was with firm end point without differences in relation to the other knee.Anterior and posterior driver's tests were negative, as on the other knee.Varus stress test was without lateral opening despite X-ray and CT examination revealed pseudoarthrosis of head of the fibula (Fig. 2).According to the literature, avulsion of the head of fibula is described as a possible indicator of posterolateral instability of the knee mostly associated with other knee structure injuries.These injuries can occurwhen anteromedial region of tibia sustain direct hit while knee is fully extended.Rarely, grade III of LCL tears can be isolated and these result from forces of lower magnitude3.High intensity force applied to the knee usually affects additional structures in the area.Only Phadnis et al reported isolated avulsion fracture of fibular head which occurred during a primary total knee replacement.
Physical examination right after injury does not have any specific findings.Specific orthopedic examination most often reveals posterolateral instability of grade 2 or more.These specific clinical tests are: varus opening at 20 degrees, posterolateral drawer test, external rotation at 30 degrees and 90 degrees (Dial test), and the reverse pivot shift.Next step should be making anteroposterior (AP) and lateral X ray which could reveal so-called arcuate sign a small fragment of proximal fibula17.As to the results of Huang et all15 this fractures fragment most often is horizontally oriented, no more than 1 cm in length, and displaced medially and superiorly by traction of conjoined lateral collateral ligament and biceps femoris tendon17.This small fragmentusually is overseen and masked by other knee joint bony structures, but CT scan or MRI can easily visualize its size, and adjacent softtissue injuries as we did in this case.
When isolated grade III LCL rupture is present, further treatment could be operative or non-operative.Bushnell et al 3 compared operatively and nonoperatively treated nine football players withgrade III isolated LCL injuries.As to results both groups had good functional outcome, but those players treated nonoperatively returned to play 9 weeks earlier.In theoperated group three out of four patients had avulsion fracture of fibular head, and in non-operative group only one out of five.Phadnis et al 16 reported isolated avulsion fracture of fibular head treated nonoperatively with good results.This fracture occurred during a primary total knee arthroplasty with no late varus instability.
Avulsion fractures of proximal fibula are well described and primary repair has been recommended when occurring with other knee injuries.But very limited data exist in the literature about surgical technique and clinical results of isolated LCL injuries.Our patient was professional football player with clinically significant knee instability on varus stress test and that is why we decided to treat him operatively.We didn't want to take chance of having remaining knee instability in young professional football player.Fixation was achieved with metal sutures and despite pseudoarthrosis of avulsed fragment, there was no clinically instability of knee, and he continued playing football for many years after with no complaint.

Conclusion
Early diagnostic of isolated fibular head fracture enables adequate treatment, and anatomic reduction of avulsed fragment is achieved easily.Absence of additional injuries of the knee leads to faster and full functional recovery of these patients with no residual ligament instability.

LITERATURE
), with no rupture, and avulsion of the head of the fibula (Fig2).

Fig. 3 -
Fig. 3 -Postoperative X ray and CT scan: A-postoperative X ray anteroposterior view; Bpostoperative X ray lateral view; C and D-postoperative CT scans.