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Arthroscopically Assisted Reduction of a Lateral Femoral Notch in Acute Tear of the Anterior Cruciate Ligament
Case Report
Arthroscopically Assisted Reduction of a Lateral Femoral Notch in Acute Tear of the Anterior Cruciate Ligament Philip A. Sadlo, M.D., and Wolfgang Nebelung, M.D., Ph.D.
Abstract: We report the case of a 20-year-old soccer player who suffered a tear of the anterior cruciate ligament with a depression fracture of the lateral femoral condyle. In addition to repairing the ligament we were able to arthroscopically reduce the depression fracture using a bioabsorbable screw. We tamped the surrounding cancellous bone with dilatators and chisels to create a bearing for an interference screw. This prepared for the placing of the screw and resulted in a sufficient reshaping of the condyle. We then inserted a threaded bioabsorbable interference screw into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity. Postoperative magnetic resonance imaging showed a significant reduction of the fracture. Key Words: Lateral femoral notch—Arthroscopic fracture reduction—Anterior cruciate ligament.
A
n infrequent finding in tears of the anterior cruciate ligament (ACL) is the lateral femoral notch, which describes an impacted osteochondral fracture of the lateral condylopatellar sulcus.1-5 Valgus stress during trauma causes the tearing of the ACL and the impaction of the posterior aspect of the lateral tibial plateau with the middle to anterior portion of the lateral femoral condyle against one another.2 This kind of fracture is visible in plain lateral radiographs of the knee and can be confirmed by magnetic resonance imaging (MRI) to distinguish it from a prominent but normal lateral condylopatellar sulcus.2 Common treatment options include open elevation of the
From the Department of Arthroscopic Surgery, Marienkrankenhaus Orthopedic Hospital, Düsseldorf, Germany. Address correspondence and reprint requests to Wolfgang Nebelung, M.D., Ph.D., Department of Arthroscopic Surgery, Marienkrankenhaus Orthopedic Hospital, An St. Swidbert 17, 40489 Düsseldorf, Germany. E-mail: [email protected] © 2006 by the Arthroscopy Association of North America Cite this article as: Sadlo PA, Nebelung W. Arthroscopically assisted reduction of a lateral femoral notch in acute tear of the anterior cruciate ligament. Arthroscopy 2006;22:574.e1-574.e3 [doi:10.1016/j.arthro.2005.11.006]. 0749-8063/06/2205-4659$32.00/0 doi:10.1016/j.arthro.2005.11.006
fracture with fixation, chondroplasty, or merely ACL reconstruction.3-6 To our knowledge, there are no previous reports of an arthroscopically performed reduction of this type of injury.
CASE REPORT A 20-year-old male college student injured his left knee while playing soccer. The patient reported twisting his knee and being tackled by an opponent while retaining this position. This led to an audible popping sound from the joint followed by swelling and pain; later, subjective instability ensued. Three days later, he underwent arthroscopic surgery at a local hospital where a tear of the ACL with a concomitant impaction fracture of the lateral condyle was diagnosed. Additional MRI confirmed a complete tear of the ACL and a considerable impression of the lateral condyle with no sign of cartilaginous fracture (Fig 1). He was transferred to our hospital where he underwent ACL reconstruction using autologous hamstring tendons 9 days after the initial trauma. During the same procedure, we performed the reduction of the depression fracture. To achieve this, we tamped the surrounding cancellous bone with dila-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 22, No 5 (May), 2006: pp 574.e1-574.e3
574.e1
574.e2
P. SADLO AND W. NEBELUNG
FIGURE 3. Postoperative sagittal MRI showing elevation of the lateral femoral depression fracture by use of a bioabsorbable interference screw.
the procedure, no ligament instability persisted and there was normal range of motion and no pain. FIGURE 1. Preoperative sagittal MRI showing a depression fracture of the lateral femoral condyle.
tators and chisels, thus creating a bearing for an interference screw, facilitating the placing of the screw, and resulting in a sufficient reshaping of the condyle. Then a threaded 7 ⫻ 23 mm bioabsorbable interference screw (Arthrex, Naples, FL) was inserted into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity (Fig 2). The postoperative MRI (Fig 3) showed a significant reduction of the fracture compared with the preoperative MRI. The knee was placed into a long-hinged knee brace with minimized weight-bearing and progressive range of motion exercises for 6 weeks postoperatively. After 6 weeks, the patient had achieved a range of motion similar to the contralateral knee. Six months after
DISCUSSION This case exemplifies the possibility to treat a lateral femoral depression fracture or “lateral notch” associated with an acute ACL tear via a minimal surgical approach with good results. Subchondral edema of the lateral condyle is a frequent finding on MRI after acute ACL injury,4 and sometimes a depression fracture in this area ensues. It has been attributed to chronic instability in the past by some authors.3,7 This might lead to neglecting the necessity to reduce such a fracture, and newer reports even describe the lateral notch to be a rare but significant radiologic sign for acute ACL tear.4-6 We believe that reduction of the lateral notch not only postpones future osteoarthritis but also contributes to graft stability due to decreased valgus stress. Further studies are needed to establish this concept. Using a minimally invasive approach as opposed to open reconstruction decreases the trauma to the joint and gives hope for satisfactory results. It is an easily performed method of treatment for reduction of the lateral notch and should be considered if a large lateral notch is present. REFERENCES
FIGURE 2. (1) Depression fracture of the lateral femoral condyle. (2) The bone above the impaction is treated with chisel and dilatator to elevate the impaction to level. (3) A screw is inserted into the previously created space to stabilize the result.
1. Cobby MJ, Schweitzer ME, Resnick D. The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament. Radiology 1992;184:855-858.
ARTHROSCOPIC REDUCTION OF A LATERAL NOTCH 2. Kaplan PA, Walker CW, Kilcoyne RF, Brown DE, Tusek D, Dussault RG. Occult fracture patterns of the knee associated with anterior cruciate ligament tears: assessment with MR imaging. Radiology 1992;183:835-838. 3. Warren RF, Kaplan N, Bach BR. The lateral notch sign of anterior cruciate ligament insufficiency. Am J Knee Surg 1988; 1:119-124. 4. Duke G. Pao. The Lateral Femoral Notch Sign. Radiology 2001;219:800-801.
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5. Garth WP Jr, Greco J, House MA. The lateral notch sign associated with acute anterior cruciate ligament disruption. Am J Sports Med 2000;28(1):68-73. 6. Garth WP Jr, Wilson T. Open reduction of a lateral femoral notch associated with an acute anterior cruciate ligament tear. Arthroscopy 2001;17(8):874-7. 7. Bach BR. Knee and leg: Soft tissue trauma, In: Orthopaedic knowledge update 5. Kasser JR ed. Rosemont: American Academy of Orthopaedic Surgeons, 1996;463-464.
Arthroscopically Assisted Reduction of a Lateral Femoral Notch in Acute Tear of the Anterior Cruciate Ligament Philip A. Sadlo, M.D., and Wolfgang Nebelung, M.D., Ph.D.
Abstract: We report the case of a 20-year-old soccer player who suffered a tear of the anterior cruciate ligament with a depression fracture of the lateral femoral condyle. In addition to repairing the ligament we were able to arthroscopically reduce the depression fracture using a bioabsorbable screw. We tamped the surrounding cancellous bone with dilatators and chisels to create a bearing for an interference screw. This prepared for the placing of the screw and resulted in a sufficient reshaping of the condyle. We then inserted a threaded bioabsorbable interference screw into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity. Postoperative magnetic resonance imaging showed a significant reduction of the fracture. Key Words: Lateral femoral notch—Arthroscopic fracture reduction—Anterior cruciate ligament.
A
n infrequent finding in tears of the anterior cruciate ligament (ACL) is the lateral femoral notch, which describes an impacted osteochondral fracture of the lateral condylopatellar sulcus.1-5 Valgus stress during trauma causes the tearing of the ACL and the impaction of the posterior aspect of the lateral tibial plateau with the middle to anterior portion of the lateral femoral condyle against one another.2 This kind of fracture is visible in plain lateral radiographs of the knee and can be confirmed by magnetic resonance imaging (MRI) to distinguish it from a prominent but normal lateral condylopatellar sulcus.2 Common treatment options include open elevation of the
From the Department of Arthroscopic Surgery, Marienkrankenhaus Orthopedic Hospital, Düsseldorf, Germany. Address correspondence and reprint requests to Wolfgang Nebelung, M.D., Ph.D., Department of Arthroscopic Surgery, Marienkrankenhaus Orthopedic Hospital, An St. Swidbert 17, 40489 Düsseldorf, Germany. E-mail: [email protected] © 2006 by the Arthroscopy Association of North America Cite this article as: Sadlo PA, Nebelung W. Arthroscopically assisted reduction of a lateral femoral notch in acute tear of the anterior cruciate ligament. Arthroscopy 2006;22:574.e1-574.e3 [doi:10.1016/j.arthro.2005.11.006]. 0749-8063/06/2205-4659$32.00/0 doi:10.1016/j.arthro.2005.11.006
fracture with fixation, chondroplasty, or merely ACL reconstruction.3-6 To our knowledge, there are no previous reports of an arthroscopically performed reduction of this type of injury.
CASE REPORT A 20-year-old male college student injured his left knee while playing soccer. The patient reported twisting his knee and being tackled by an opponent while retaining this position. This led to an audible popping sound from the joint followed by swelling and pain; later, subjective instability ensued. Three days later, he underwent arthroscopic surgery at a local hospital where a tear of the ACL with a concomitant impaction fracture of the lateral condyle was diagnosed. Additional MRI confirmed a complete tear of the ACL and a considerable impression of the lateral condyle with no sign of cartilaginous fracture (Fig 1). He was transferred to our hospital where he underwent ACL reconstruction using autologous hamstring tendons 9 days after the initial trauma. During the same procedure, we performed the reduction of the depression fracture. To achieve this, we tamped the surrounding cancellous bone with dila-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 22, No 5 (May), 2006: pp 574.e1-574.e3
574.e1
574.e2
P. SADLO AND W. NEBELUNG
FIGURE 3. Postoperative sagittal MRI showing elevation of the lateral femoral depression fracture by use of a bioabsorbable interference screw.
the procedure, no ligament instability persisted and there was normal range of motion and no pain. FIGURE 1. Preoperative sagittal MRI showing a depression fracture of the lateral femoral condyle.
tators and chisels, thus creating a bearing for an interference screw, facilitating the placing of the screw, and resulting in a sufficient reshaping of the condyle. Then a threaded 7 ⫻ 23 mm bioabsorbable interference screw (Arthrex, Naples, FL) was inserted into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity (Fig 2). The postoperative MRI (Fig 3) showed a significant reduction of the fracture compared with the preoperative MRI. The knee was placed into a long-hinged knee brace with minimized weight-bearing and progressive range of motion exercises for 6 weeks postoperatively. After 6 weeks, the patient had achieved a range of motion similar to the contralateral knee. Six months after
DISCUSSION This case exemplifies the possibility to treat a lateral femoral depression fracture or “lateral notch” associated with an acute ACL tear via a minimal surgical approach with good results. Subchondral edema of the lateral condyle is a frequent finding on MRI after acute ACL injury,4 and sometimes a depression fracture in this area ensues. It has been attributed to chronic instability in the past by some authors.3,7 This might lead to neglecting the necessity to reduce such a fracture, and newer reports even describe the lateral notch to be a rare but significant radiologic sign for acute ACL tear.4-6 We believe that reduction of the lateral notch not only postpones future osteoarthritis but also contributes to graft stability due to decreased valgus stress. Further studies are needed to establish this concept. Using a minimally invasive approach as opposed to open reconstruction decreases the trauma to the joint and gives hope for satisfactory results. It is an easily performed method of treatment for reduction of the lateral notch and should be considered if a large lateral notch is present. REFERENCES
FIGURE 2. (1) Depression fracture of the lateral femoral condyle. (2) The bone above the impaction is treated with chisel and dilatator to elevate the impaction to level. (3) A screw is inserted into the previously created space to stabilize the result.
1. Cobby MJ, Schweitzer ME, Resnick D. The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament. Radiology 1992;184:855-858.
ARTHROSCOPIC REDUCTION OF A LATERAL NOTCH 2. Kaplan PA, Walker CW, Kilcoyne RF, Brown DE, Tusek D, Dussault RG. Occult fracture patterns of the knee associated with anterior cruciate ligament tears: assessment with MR imaging. Radiology 1992;183:835-838. 3. Warren RF, Kaplan N, Bach BR. The lateral notch sign of anterior cruciate ligament insufficiency. Am J Knee Surg 1988; 1:119-124. 4. Duke G. Pao. The Lateral Femoral Notch Sign. Radiology 2001;219:800-801.
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5. Garth WP Jr, Greco J, House MA. The lateral notch sign associated with acute anterior cruciate ligament disruption. Am J Sports Med 2000;28(1):68-73. 6. Garth WP Jr, Wilson T. Open reduction of a lateral femoral notch associated with an acute anterior cruciate ligament tear. Arthroscopy 2001;17(8):874-7. 7. Bach BR. Knee and leg: Soft tissue trauma, In: Orthopaedic knowledge update 5. Kasser JR ed. Rosemont: American Academy of Orthopaedic Surgeons, 1996;463-464.