Tips & Techniques

Isolated Avulsion Fracture of the Fibular Head: A New Fixation Technique Using a Suture Anchor

Hyung Keun Oh, MD; Jung Hoon Kim, MD; Chang Soo Lee, MD; Prabhat Kumar Singh, MS; Kook Hyun Wang, MD; Kyung Wook Nha, MD

  • Orthopedics
  • February 2011 - Volume 34 · Issue 2: 100-104
  • DOI: 10.3928/01477447-20101221-19
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A new fixation technique for acute fibular head avulsion fractures using a suture anchor provides a rigid, anatomic fixation, allowing early mobilization, and influencing the long-term outcome of these injuries.
Cover illustration © Brian Evans
Cover illustration © Brian Evans

Isolated fibular head avulsion fractures are rare. They may occur with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) tears, or injuries to the stabilizing structures of the posterolateral corner of the knee.1-3 These injuries are treated surgically, especially when associated with other ligamentous injuries. This article describes a new, secure fixation treatment technique using a bioabsorbable screw-type suture anchor.

Materials and Methods

Seven consecutive patients underwent open reduction and internal fixation (ORIF) for isolated avulsion fractures of the fibular head using bioabsorbable screw-type suture anchors between January 2004 and March 2008. Mean patient age was 41 years (range, 23-53 years). There were 5 men and 2 women. The mechanisms of injury were a collision with players in baseball, a fall from a 2-m height, and 5 traffic accidents (Table). Preoperative radiological examination included anteroposterior (AP) and lateral radiographs of the knee. Computed tomography (CT) scans or magnetic resonance images (MRIs) were taken for all patients (Figure 1). The mean interval between the time of injury and surgery was 2.6 days (range, 1-5 days).

Table: Patient Data at Last Follow-up

Figure 1A: An avulsion fracture Figure 1B: An avulsion fracture
Figure 1: Preoperative plain AP radiograph of the left knee showing an avulsion fracture of the fibular head (arrow) with widening of the lateral compartment (A). Preoperative T1-weighted coronal section of MRI showing avulsed fibular head (arrow) with attachment of biceps femoris tendon (B).

The clinical symptoms and physical findings of all patients were evaluated preoperatively and 2 years postoperatively. In addition to cruciate ligament tests, a specific posterolateral corner evaluation was performed. The dial test (at 30° and 90° knee flexion) and the varus stress test (at 0° and 30° knee flexion) were performed, respectively, in prone and supine positions, under spinal or general anesthesia. The surgical indication was acute isolated avulsion fracture of the fibular head, performed after positivity of the dial test, varus stress test, and MRI examination. However, the exclusion criteria of the study were: chronic nonunion of avulsed fibular fragment, associated posterolateral ligament injury that both clinically and radiologically required surgical reconstruction, and comminution of avulsed fibular fragment where suture tunnels could not be created. For combined ligament injuries, patients underwent single-bundle ACL reconstruction using hamstring tendon allograft with fixation of the avulsion fracture in the same procedure.

At final follow-up, all patients were evaluated for knee range of motion, a knee instability test including: Lachman and varus tests, KT-2000 arthrometer (MEDmetric), Lysholm knee scores, and International Knee Documentation Committee (IKDC) scores.

Surgical Technique

All operations were performed using spinal anesthesia or continuous epidural anesthesia combined with spinal anesthesia. Patients were placed in the supine position on the operating table, and the lower limb tourniquet was inflated.

Following the single-bundle ACL reconstruction, a lateral curvilinear incision was made with the incision passing midway between Gerdy’s tubercle and the fibular head on the lateral surface of the knee (Figure 2). The iliotibial band and the biceps femoris tendon were exposed (Figure 3A).

Figure 2: A lateral curvilinear incision
Figure 2: A lateral curvilinear incision made passing midway between Gerdy’s tubercle and the fibular head on the lateral surface of the knee.

The peroneal nerve was identified posterior to the biceps tendon. The iliotibial band was incised in line with its fibers beginning at the point where it crosses the lateral femoral epicondyle and proceeding distally. This exposed the insertion point of both the fibular collateral ligament as well as the popliteus tendon on the lateral femoral condyle (Figure 3B). The peroneal nerve was explored and freed as it passed beneath the fascia in the anterolateral compartment of the lower leg. The avulsed fragment had retracted proximally by approximately 2 cm. Inspection of the other posterolateral corner structures revealed they were intact. Blunt dissection was carried out around the biceps tendon to mobilize it and aid in reduction of the fragment. A bioabsorbable screw-type suture anchor with 2 suture ties (Spiralok, Emhart Technologies, Madison Heights, Michigan and Orthocord, DePuy Orthopedics Inc, Warsaw, Indiana) was then fastened to the cancellous part of the main fibular head at the avulsed site. Four suture tunnels were drilled in the avulsed fragment with the help of a 1.5-mm K-wire. The anchor ties were passed through the suture tunnels (Figure 4). The fragment was then held reduced and the sutures were tied to each other over the avulsed fragment.

Figure 3A: Schematic showing the exposed iliotibial band Figure 3B: Schematic showing the exposed iliotibial band
Figure 3: Schematic showing the exposed iliotibial band and the biceps femoris (A). Abbreviations: BT, biceps tendon; IT, iliotibial band. After the iliotibial band was incised in line with its fibers, the insertion point of the lateral collateral ligament as well as the popliteus tendon were exposed (B). The avulsed fibular head (red arrow) was seen. Abbreviations: IT band, iliotibial band; LCL, lateral collateral ligament.

Figure 4: Schematic diagram
Figure 4: Schematic diagram showing the bioabsorbable suture anchor (C) seated at the fracture site and with the suture ties (D) passing through tunnels made in the avulsed fragment (B), which is attached to the biceps femoris tendon and fibular collateral ligament (A).

The fixation was secure and augmented with the surrounding soft tissues around the biceps femoris tendon. Postoperative radiographs showed satisfactory reduction of the avulsed fracture fragment (Figure 5). Patients were placed in an above-knee back splint for 2 weeks postoperatively with gentle knee ROM exercises. Patients achieved 90° knee flexion by 4 weeks postoperatively. No resisted flexion was allowed during this time. At the end of 8 weeks postoperatively, each patient had full ROM and began mobilizing using walkers.

Figure 5A: Good reduction of the avulsed fragment Figure 5B: Good reduction of the avulsed fragment
Figure 5: At 2 years postoperatively, plain AP radiograph (A) and CT (B) of the left knee showing good reduction of the avulsed fragment (arrow).

Results

All 7 patients returned for clinical and radiographic follow-ups at a minimum of 2 years. No intraoperative or postoperative complications such as fixation failure or infection were found. At 2 years postoperatively, none of the patients reported pain or instability. Bone union was observed in all patients. The mean time to achieve bone union was 20.5 weeks (range, 17-28 weeks). All patients regained full ROM without flexion contracture. The overall IKDC grade at 2 years postoperatively was normal in 4 knees and near normal in 3 knees. Lysholm knee score showed a mean value of 91.6 points (range, 87-95 points) and IKDC score showed 89.6 points (range, 85–93 points). In the 6 patients who underwent ACL reconstruction, Lachman and pivot shift tests were less than grade II, and KT-2000 arthrometer testing showed no anterior instability exceeding 3 mm compared to normal contralateral knees. Of 7 patients, 5 showed grade I and 2 showed grade II on varus stress tests (Table).

Discussion

Avulsion fractures of the fibular head usually occur following sports injuries or traffic accidents from excessive varus stress about the knee. Associated injuries to the posterolateral structures, the cruciate ligaments, and the peroneal nerve are common.1-4 The biceps femoris tendon and fibular collateral ligament insert into the upper lateral part of the fibular head as a conjoined tendon. These structures provide stability to the lateral aspect of the knee joint, which is vital for optimal knee function.5

It is difficult to distinguish an avulsion fracture of the fibular head from that of the arcuate sign of posterolateral corner injury on conventional radiographs alone, although the arcuate sign tends to have a more characteristic appearance as an elliptic fragment with its axis oriented horizontally on AP views. Avulsion fracture of the biceps femoris tendon appears as an irregular bone fragment rising from the fibular head.6 The integrity of the posterolateral corner in each patient was confirmed during intraoperative inspection.

Fibular head avulsion fractures should be treated early before capsular scarring and soft tissue stretching occur. Rigid fixation and early mobilization is necessary for favorable surgical outcome. However, this is frequently not possible, especially when the avulsed fragment is small. Reports of these fractures in the literature describe them being treated by internal fixation with a screw and suturing through osseous tunnels.7 Repair with a screw is ideal in patients with avulsions. However, comminution can occur during this fixation when the avulsed fragment is small.

Suture anchors have been used in orthopedic surgery to provide strong fixation of capsules, ligaments, and tendons.8-10 It is currently the standard method of arthroscopic shoulder stabilization. It has also been used for tibial spine avulsion fracture fixation11 and ankle ligament reconstruction.12 Suture anchors have been shown to be superior to transglenoid sutures in arthroscopic shoulder surgeries with regard to treatment outcomes and biomechanical superiority.10,13

In each patient, a suture anchor was fastened to the fibula at the fracture site. The suture ties were passed through the suture tunnels in the avulsed fragment, securing it firmly to its native site. The repair was augmented by the surrounding soft tissues around the biceps tendon. The operative technique presented here has several advantages: (1) the suture fixation technique requires no further surgery for implant removal, and (2) suture fixation is superior to screw fixation for treating avulsion fracture of the fibular head because screw fixation may potentially break the fibular fragment. By this method, we were able to achieve a fixation that was rigid enough to allow knee mobilization within a few days following repair. Additionally, suture anchors can be used with cement, even in osteoporotic bone.

To our knowledge, this is the first report of a suture anchor being used for fixation of an isolated avulsion fracture of the fibular head. However, our study had some limitations, including a short follow-up. Moreover, the sample size was small, and no prospective data exist regarding this type of treatment in the literature. However, the study has some strengths. A single surgeon (K.W.N.) used a standardized surgical technique in a consecutive series of patients with isolated avulsion fractures of the fibular head with the same fixation method.

Conclusion

We recommend the usage of this fixation device in acute avulsion fractures of the fibular head, even if associated with posterolateral corner or cruciate ligament injuries, to provide a rigid, anatomic fixation and allow early mobilization, directly influencing the long-term outcome of these injuries.

References

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  2. Juhng SK, Lee JK, Choi SS, Yoon KH, Roh BS, Won JJ. MR evaluation of the “arcuate” sign of posterolateral knee instability. AJR Am J Roentgenol. 2002; 178(3):583-588.
  3. Lee J, Papakonstantinou O, Brookenthal KR, Trudell D, Resnick DL. Arcuate sign of posterolateral knee injuries: anatomic, radiographic, and MR imaging data related to patterns of injury [published online ahead of print October 1, 2003]. Skeletal Radiol. 2003; 32(11):619-627.
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  7. Baker CL Jr, Norwood LA, Hughston JC. Acute posterolateral rotatory instability of the knee. J Bone Joint Surg Am. 1983; 65(5):614-618.
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  9. Kandziora F, Jager A, Bischof F, Herresthal J, Starker M, Mittlmeier T. Arthroscopic labrum refixation for post-traumatic anterior shoulder instability: suture anchor versus transglenoid fixation technique. Arthroscopy. 2000;16(4):359-366.
  10. van Oostveen DP, Schild FJ, van Haeff MJ, Saris DB. Suture anchors are superior to transglenoid sutures in arthroscopic shoulder stabilization. Arthroscopy. 2006; 22(12):1290-1297.
  11. In Y, Kim JM, Woo YK, Choi NY, Moon CW, Kim MW. Arthroscopic fixation of anterior cruciate ligament tibial avulsion fractures using bioabsorbable suture anchors [published online ahead of print December 22, 2007]. Knee Surg Sports Traumatol Arthrosc. 2008; 16(3):286-289.
  12. Messer TM, Cummins CA, Ahn J, Kelikian AS. Outcome of the modified Broström procedure for chronic lateral ankle instability using suture anchors. Foot Ankle Int. 2000; 21(12):996-1003.
  13. Barber FA, Herbert MA, Richards DP. Sutures and suture anchors: update 2003. Arthroscopy. 2003; 19(9):985-990.

Authors

Drs Oh, Kim, Lee, Wang, and Nha and Mr Singh are from the Department of Orthopedic Surgery, Inje University, Ilsan Paik Hospital, Goyangsi, Korea.

Drs Oh, Kim, Lee, Wang, and Nha and Mr Singh have no relevant financial relationships to disclose.

Correspondence should be addressed to: Kyung Wook Nha, MD, 2240 Daehwa dong, Ilsanseogu, Goyangsi, Gyeonggido, South Korea, 411-706 (kwnhamj@hotmail.com).

doi: 10.3928/01477447-20101221-19

doi: 10.3928/01477447-20101221-19

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