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Osteochondritis dissecans of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and anterior cruciate ligament
Case Report
Osteochondritis Dissecans of the Medial Femoral Condyle Associated With Congenital Hypoplasia of the Lateral Meniscus and Anterior Cruciate Ligament Tomoki Mitsuoka, M.D., Shuji Horibe, M.D., and Masayuki Hamada, M.D.
Summary: We report a patient with osteochondritis dissecans of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and anterior cruciate ligament. This is the first report of such a case. Key Words: Osteochondritis dissecans—Knee—Lateral meniscus—Anomaly—Hypoplasia.
O
steochondritis dissecans (OCD) of the knee joint usually affects the femoral condyles in younger people. However, OCD is rarely associated with congenital abnormality other than discoid lateral menisci.1,2 We report a patient with OCD of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and the anterior cruciate ligament. CASE REPORT A 13-year-old boy complained of pain and swelling of his left knee for 6 months. He had played junior league baseball without any knee symptoms for 3 years before onset. His knee alignment was valgus (femorotibial angle, 170°) (Fig 1). The knee was swollen and the range of motion was limited from 0 to 105°. There was no ligamentous instability. Anteroposterior radiograph showed OCD of the medial femoral condyle at the classical site3 and a loose body at the suprapatella pouch (Fig 2). Notch width index (NWI) measured by tunnel-view radiograph4 was 0.154 (Fig
From the Department of Orthopaedic Sports Medicine, Osaka Rosai Hospital, Osaka, Japan. Address correspondence and reprint requests to Tomoki Mitsuoka, M.D., 1179-3, Nagasone-Cho, Sakai-Shi, Osaka 591, Japan. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1406-1834$3.00/0
630
FIGURE 1.
Valgus knee alignment (femorotibial angle, 170°).
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 6 (September), 1998: pp 630–633
FIGURE 2. (A) Anteroposterior radiograph showing OCD of the medial femoral condyle. (B) Lateral radiograph showing a free body at the suprapatellar pouch.
FIGURE 3.
Tunnel view showing narrow intercondylar notch.
FIGURE 4. Magnetic resonance image showing absence of the lateral meniscus and OCD of medial femoral condyle.
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T. MITSUOKA ET AL.
FIGURE 5. Arthroscopy of left knee. (A) Absent lateral meniscus and fibrillated lateral tibial plateau. (B) Normal semilunar medial meniscus. (C) Narrow intercondylar notch and anterior cruciate ligament like a string. (D) Large tibial spine.
3). Magnetic resonance imaging revealed that the lateral meniscus was absent (Fig 4). Because of the patient’s persistent long-term symptoms, arthroscopy was performed. Arthroscopically, the medial meniscus was seen to be normal, but the lateral meniscus was hypoplastic; its body was absent and only the meniscal rim could be seen. The anterior cruciate ligament looked like a string. The articular cartilage of the lateral tibial plateau was fibrillated. A narrow intercondylar notch with a large intercondylar eminence was observed (Fig 5). After the loose body at the suprapatellae pouch was removed, the OCD lesion was drilled with K-wire. Arthroscopic examination of the right knee was also performed. Although the medial meniscus was normal, both the lateral meniscus and anterior cruciate liga-
ment were hypoplastic—similar to those in the left knee (Fig 6). Six months postoperatively, the patient was free of symptoms during activities of daily living, and radiographs showed healing of the OCD. However, minimal swelling of his left knee was observed after strenuous sports activity.
DISCUSSION Congenital abnormalities of both menisci and cruciate ligament are extremely rare5,6 and usually combined with another severe abnormality such as thrombocytopenia with absent radius syndrome. According to previous English literature, however, congenital
CONGENITAL HYPOPLASIA OF THE LATERAL MENISCUS
FIGURE 6.
633
Arthroscopy of right knee. (A) Absent lateral meniscus except for anterior rim. (B) Normal semilunar medial meniscus.
hypoplasia of the lateral meniscus and the anterior cruciate ligament is usually not associated with OCD. From the work of Kaplan,7 McDermott,8 Gardner and O’Rahilly,9 and Gray and Gardner,10 it seems that the menisci and anterior cruciate ligament develop from the same knee mesenchymal blastema about 9 weeks after conception. Therefore, it is clear that developmental abnormality until 9 weeks after conception caused hypoplasia of the lateral meniscus and anterior cruciate ligament in our case. Concerning the etiology of OCD of the knee, several possibilities have been proposed. Katz et al.11 described four knees with complete absence of the anterior cruciate ligament, and indicated that the radiographs showed a narrow intercondylar notch. Similar to his cases, the intercondylar notch of this case was considered narrow, because the NWI was 0.154 compared with the normal NWI of 0.231 ⫾ 0.044.12 Smillie13 proposed that the anterior tibial spine impinges on the medial femoral condyle during the last few degrees of knee extension. Therefore, the main cause of OCD in our case was thought to be the anterior tibial spine impinging on the medial femoral condyle because of the narrow intercondylar notch. In our case, OCD was the main cause of symptoms, and knee instability was not detected. Therefore, hypoplasia of lateral meniscus and anterior cruciate ligament was considered a benign and rare condition. Six month postoperatively, the patient became free of
symptoms in daily activity. However, careful follow-up is needed to monitor the possibility of progressive osteoarthritic change. REFERENCES 1. Irani RN, Karasick D, Karasick S. A possible explanation of the pathogenesis of osteochondritis dissecans. J Pediatr Surg 1984;4:358-360. 2. Aichroch PM, Patel DV, Marx CL. Congenital discoid lateral meniscus in children. J Bone Joint Surg Br 1991;73:932-936. 3. Airchroth PM: Osteochondritis dissecans of the knee. A clinical survey. J Bone Joint Surg Br 1971;53:440-447. 4. Souryal TO, Moore HA, Evans JP. Bilaterality in anterior cruciate ligament injuries. Am J Sports Med 1988;16:449-454. 5. Hall JG, Lenin J, Kuhn JP, Ottenheimer EJ, Von Gerkum KAP, McKusuck VA. Thrombocytopenia with absent radius. Medicine 1969;48:411-439. 6. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee. A case report. J Bone Joint Surg Am 1981;63:1022-1024. 7. Kaplan EB. The embryology of the menisci of the knee joint. Bull Hosp Joint Dis 1955;16:111-124. 8. McDermott LJ. Development of the human knee joint. Arch Surg 1943;46:705-719. 9. Gardner E, O’Rahilly R. The early development of the knee joint in staged human embryos. J Anat 1968;102:289-299. 10. Gray DJ, Gardner E. Prenatal development of the human knee and superior tibiofibular joints. Am J Anat 1950;86:235-287. 11. Karz MP, Grogono BJS, Soper KC. The etiology and treatment of congenital dislocation of the knee. J Bone Joint Surg Br 1967;49:112. 12. Souryal TO, Freeman TR. Intercondylar notch size and ACL injuries. Am J Sports Med 1993;21:535-539. 13. Smillie IS: Diseases of the knee joint. Ed 2. Edinburgh: Churchill Livingstone, 1980.
Osteochondritis Dissecans of the Medial Femoral Condyle Associated With Congenital Hypoplasia of the Lateral Meniscus and Anterior Cruciate Ligament Tomoki Mitsuoka, M.D., Shuji Horibe, M.D., and Masayuki Hamada, M.D.
Summary: We report a patient with osteochondritis dissecans of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and anterior cruciate ligament. This is the first report of such a case. Key Words: Osteochondritis dissecans—Knee—Lateral meniscus—Anomaly—Hypoplasia.
O
steochondritis dissecans (OCD) of the knee joint usually affects the femoral condyles in younger people. However, OCD is rarely associated with congenital abnormality other than discoid lateral menisci.1,2 We report a patient with OCD of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and the anterior cruciate ligament. CASE REPORT A 13-year-old boy complained of pain and swelling of his left knee for 6 months. He had played junior league baseball without any knee symptoms for 3 years before onset. His knee alignment was valgus (femorotibial angle, 170°) (Fig 1). The knee was swollen and the range of motion was limited from 0 to 105°. There was no ligamentous instability. Anteroposterior radiograph showed OCD of the medial femoral condyle at the classical site3 and a loose body at the suprapatella pouch (Fig 2). Notch width index (NWI) measured by tunnel-view radiograph4 was 0.154 (Fig
From the Department of Orthopaedic Sports Medicine, Osaka Rosai Hospital, Osaka, Japan. Address correspondence and reprint requests to Tomoki Mitsuoka, M.D., 1179-3, Nagasone-Cho, Sakai-Shi, Osaka 591, Japan. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1406-1834$3.00/0
630
FIGURE 1.
Valgus knee alignment (femorotibial angle, 170°).
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 6 (September), 1998: pp 630–633
FIGURE 2. (A) Anteroposterior radiograph showing OCD of the medial femoral condyle. (B) Lateral radiograph showing a free body at the suprapatellar pouch.
FIGURE 3.
Tunnel view showing narrow intercondylar notch.
FIGURE 4. Magnetic resonance image showing absence of the lateral meniscus and OCD of medial femoral condyle.
632
T. MITSUOKA ET AL.
FIGURE 5. Arthroscopy of left knee. (A) Absent lateral meniscus and fibrillated lateral tibial plateau. (B) Normal semilunar medial meniscus. (C) Narrow intercondylar notch and anterior cruciate ligament like a string. (D) Large tibial spine.
3). Magnetic resonance imaging revealed that the lateral meniscus was absent (Fig 4). Because of the patient’s persistent long-term symptoms, arthroscopy was performed. Arthroscopically, the medial meniscus was seen to be normal, but the lateral meniscus was hypoplastic; its body was absent and only the meniscal rim could be seen. The anterior cruciate ligament looked like a string. The articular cartilage of the lateral tibial plateau was fibrillated. A narrow intercondylar notch with a large intercondylar eminence was observed (Fig 5). After the loose body at the suprapatellae pouch was removed, the OCD lesion was drilled with K-wire. Arthroscopic examination of the right knee was also performed. Although the medial meniscus was normal, both the lateral meniscus and anterior cruciate liga-
ment were hypoplastic—similar to those in the left knee (Fig 6). Six months postoperatively, the patient was free of symptoms during activities of daily living, and radiographs showed healing of the OCD. However, minimal swelling of his left knee was observed after strenuous sports activity.
DISCUSSION Congenital abnormalities of both menisci and cruciate ligament are extremely rare5,6 and usually combined with another severe abnormality such as thrombocytopenia with absent radius syndrome. According to previous English literature, however, congenital
CONGENITAL HYPOPLASIA OF THE LATERAL MENISCUS
FIGURE 6.
633
Arthroscopy of right knee. (A) Absent lateral meniscus except for anterior rim. (B) Normal semilunar medial meniscus.
hypoplasia of the lateral meniscus and the anterior cruciate ligament is usually not associated with OCD. From the work of Kaplan,7 McDermott,8 Gardner and O’Rahilly,9 and Gray and Gardner,10 it seems that the menisci and anterior cruciate ligament develop from the same knee mesenchymal blastema about 9 weeks after conception. Therefore, it is clear that developmental abnormality until 9 weeks after conception caused hypoplasia of the lateral meniscus and anterior cruciate ligament in our case. Concerning the etiology of OCD of the knee, several possibilities have been proposed. Katz et al.11 described four knees with complete absence of the anterior cruciate ligament, and indicated that the radiographs showed a narrow intercondylar notch. Similar to his cases, the intercondylar notch of this case was considered narrow, because the NWI was 0.154 compared with the normal NWI of 0.231 ⫾ 0.044.12 Smillie13 proposed that the anterior tibial spine impinges on the medial femoral condyle during the last few degrees of knee extension. Therefore, the main cause of OCD in our case was thought to be the anterior tibial spine impinging on the medial femoral condyle because of the narrow intercondylar notch. In our case, OCD was the main cause of symptoms, and knee instability was not detected. Therefore, hypoplasia of lateral meniscus and anterior cruciate ligament was considered a benign and rare condition. Six month postoperatively, the patient became free of
symptoms in daily activity. However, careful follow-up is needed to monitor the possibility of progressive osteoarthritic change. REFERENCES 1. Irani RN, Karasick D, Karasick S. A possible explanation of the pathogenesis of osteochondritis dissecans. J Pediatr Surg 1984;4:358-360. 2. Aichroch PM, Patel DV, Marx CL. Congenital discoid lateral meniscus in children. J Bone Joint Surg Br 1991;73:932-936. 3. Airchroth PM: Osteochondritis dissecans of the knee. A clinical survey. J Bone Joint Surg Br 1971;53:440-447. 4. Souryal TO, Moore HA, Evans JP. Bilaterality in anterior cruciate ligament injuries. Am J Sports Med 1988;16:449-454. 5. Hall JG, Lenin J, Kuhn JP, Ottenheimer EJ, Von Gerkum KAP, McKusuck VA. Thrombocytopenia with absent radius. Medicine 1969;48:411-439. 6. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee. A case report. J Bone Joint Surg Am 1981;63:1022-1024. 7. Kaplan EB. The embryology of the menisci of the knee joint. Bull Hosp Joint Dis 1955;16:111-124. 8. McDermott LJ. Development of the human knee joint. Arch Surg 1943;46:705-719. 9. Gardner E, O’Rahilly R. The early development of the knee joint in staged human embryos. J Anat 1968;102:289-299. 10. Gray DJ, Gardner E. Prenatal development of the human knee and superior tibiofibular joints. Am J Anat 1950;86:235-287. 11. Karz MP, Grogono BJS, Soper KC. The etiology and treatment of congenital dislocation of the knee. J Bone Joint Surg Br 1967;49:112. 12. Souryal TO, Freeman TR. Intercondylar notch size and ACL injuries. Am J Sports Med 1993;21:535-539. 13. Smillie IS: Diseases of the knee joint. Ed 2. Edinburgh: Churchill Livingstone, 1980.