Skeletal Radiol DOI 10.1007/s00256-014-1835-4
CASE REPORT
Subchondral insufficiency fracture of the femoral head after internal fixation for femoral neck fracture: histopathological investigation Kazuhiko Sonoda & Takuaki Yamamoto & Goro Motomura & Hidehiko Kido & Yukihide Iwamoto
Received: 23 November 2013 / Revised: 16 January 2014 / Accepted: 21 January 2014 # ISS 2014
Abstract Late segmental collapse after internal fixation for femoral neck fracture is the phenomenon observed in posttraumatic osteonecrosis of the femoral head (ON), which has generally been reported to occur over a year or more after internal fixation. Subchondral insufficiency fracture of the femoral head (SIF) has also been recognized to cause femoral head collapse, however, only two cases of SIF after internal fixation for femoral neck fracture have been reported. We report a case with femoral head collapse observed 5 months after internal fixation for femoral neck fracture, which was histopathologically diagnosed as SIF. Clinically, differentiating SIF from ON is important because some cases of SIF have been reported to heal without surgical treatments. The timing of femoral head collapse after femoral neck fracture may be different between SIF and post-traumatic ON.
which is quite different from what occurs in osteonecrosis of the femoral head (ON) [2]. In ON, zone formation, comprising necrotic, reparative, and normal zone, is a characteristic appearance [3]. However, due to the similar radiographic findings with ON, several cases of SIF previously had been considered as ON [1, 2, 4]. Post-traumatic ON is well recognized as one of the major complications after femoral neck fracture [5–7]. In general, a “late segmental collapse” occurs over a year or more after treatment [8, 9]. Here we report a case that was histopathologically diagnosed as SIF in a patient who developed collapse of the femoral head 5 months after internal fixation for femoral neck fracture. It is important to recognize the occurrence of SIF after femoral neck fracture, since some cases of SIF have been reported to heal without surgical treatments [10–12].
Keywords Subchondral insufficiency fracture . Osteonecrosis of the femoral head . Femoral neck fracture
Case report
Introduction Subchondral insufficiency fracture of the femoral head (SIF) can cause femoral head collapse especially in osteoporotic elderly women [1]. One characteristic histopathological feature in SIF has been reported to be fracture callus formation with associated granulation tissue along the fracture line, K. Sonoda : T. Yamamoto (*) : G. Motomura : Y. Iwamoto Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City 812-8582, Japan e-mail: [email protected] H. Kido Department of Orthopaedic Surgery, Yamaguchi Red Cross Hospital, 53-1 Yahatababa, Yamaguchi City 753-8519, Japan
A 70-year-old female (height: 161 cm, weight: 56.0 kg, body mass index: 21.6) fractured her right femoral neck (Garden I) [13] when she fell down (Fig. 1a, b). She underwent internal fixation with two hook pins (Fig. 1c, d). The day after the operation, she started a rehabilitation program that allowed full weight bearing. Her right hip pain gradually decreased. One month after the operation, she was able to walk without a cane. Four months after the operation, her activity level recovered and she was able to complete activities of daily living without difficulty. The radiographs demonstrated a sclerotic change around the femoral neck without any evidence of femoral head collapse (Fig. 1e, f). Four and a half months after the operation, however, she experienced right hip pain suddenly after standing up from a chair. The radiographs taken 5 months after the operation demonstrated a collapse in the anterior portion of the right femoral head with associated joint space narrowing (Fig. 1g, h). Because of a severe dysfunction
Skeletal Radiol
Fig. 1 A 70-year-old female with right hip pain following a fall. a, b Anteroposterior (a) and lateral (b) radiographs of the right hip at the initial examination show femoral neck fracture (arrows). The fracture is valgus impacted type (Garden I). c, d Anteroposterior (c) and frog leg lateral (d) radiographs at the time of surgery. In situ fixation was performed using two hook pins, since this type of fracture is considered to be stable with lowest risk of developing osteonecrosis. e, f Follow-up anteroposterior (e) and frog leg lateral
(f) radiographs 4 months after internal fixation. At this time, there was no pain in the right hip. Sclerosis (arrows) around a fracture line is seen without any abnormality in the subchondral area. g, h Follow-up anteroposterior (g) and frog leg lateral (h) radiographs 5 months after internal fixation (there was right hip pain). Femoral head collapse is observed in the anterior portion (arrows) and joint space narrowing is also seen at the superior portion of the femoral head (arrowheads)
of the right hip joint, she underwent total hip arthroplasty. Post-traumatic ON was considered; however, the timing of femoral head collapse was relatively early. In order to confirm the diagnosis, histological examination was performed. Sagittal-cut section of the removed femoral head showed a whitish gray zone in the bone marrow space beneath the subchondral plate (Fig. 2a). The articular cartilage was detached from the anterior portion of the femoral head. Microscopically, a subchondral fracture line was observed (Fig. 2b). Fracture callus formation with associated granulation tissue were seen along the fracture line (Fig. 2c). Although small segments of the necrotic bone trabeculae were scattered along the fracture line, there was no evidence of antecedent bone infarction. Based on these histopathological findings, she was diagnosed as SIF.
Discussion Post-traumatic ON is well recognized as a major complication after femoral neck fracture [5–7], and previous reports showed the rate of development to be 20–30 % [14, 15]. Therefore, cases undergoing femoral head collapse after femoral neck fracture are likely to be diagnosed as post-traumatic ON. However, a recent paper reported the occurrence of SIF after femoral neck fracture based on magnetic resonance imaging (MRI) [16]. The current report, for the first time, presents histopathologic evidence of SIF after femoral neck fracture. In recent years, SIF has been recognized as an important differential diagnosis in cases showing femoral head collapse, especially in elderly women [1, 2, 4]. Several studies demonstrated that the shape of the low intensity band on T1-
Fig. 2 Histopathologic findings of the removed femoral head. a Sagittal section of the removed femoral head shows a subchondral fracture, and an irregular whitish gray zone is seen beneath the subchondral plate (arrowheads). b Full cut section of the removed femoral head. A subchondral fracture is seen in the anterior
portion (arrowheads). c This picture is obtained from the area pointed out as “c” in Fig. 2a and b. Fracture callus formation (arrows) with associated granulation tissue (arrowheads) are seen in the bone marrow space around the fracture line (hematoxylin and eosin× 40)
Skeletal Radiol
weighted MRI images is useful in differentiating SIF from ON [2, 11]. However, in patients undergoing internal fixation for femoral neck fracture, it is often difficult to obtain precise MRI images due to the implants. Based on MRI, Ikemura et al. reported two cases of SIF after removal of the implants in relatively younger age (26 and 43-year-old female) [16]. Radiographically, one case showed spherical femoral head with patchy areas of osteosclerosis, while another case showed no abnormality. On the other hand, the current case (70-year-old female) showed progressed femoral head collapse with associated joint space narrowing at a half month after the onset. Bone fragility due to the elderly age might have affected such a rapid progression of collapse [17]. Clinically, femoral head collapse caused by post-traumatic ON usually occurs over a year or more after internal fixation [8, 9]. On the other hand, in our case, femoral head collapse in conjunction with joint space narrowing was observed 5 months after the operation, which seems to be early compared with the typical onset of late segmental collapse in posttraumatic ON. We speculate that the timing of collapse after femoral neck fracture may be different between SIF and posttraumatic ON. SIF should be considered as one of the differential diagnoses for post-traumatic ON after internal fixation for femoral neck fracture. Acknowledgement This work was supported in part by a Grant-in-Aid for Scientific Research (No.24592266) from the Japan Society for the Promotion of Science and a Research Grant for Intractable Diseases from the Ministry of Health and Welfare of Japan. Conflict of interest The authors declare that they have no conflicts of interest.
References 1. Yamamoto T, Iwamoto Y, Schneider R, Bullough PG. Histopathological prevalence of subchondral insufficiency fracture of the femoral head. Ann Rheum Dis. 2008;67:150–3.
2. Yamamoto T, Schneider R, Bullough PG. Insufficiency subchondral fracture of the femoral head. Am J Surg Pathol. 2000;24:464–8. 3. Yamamoto T, DiCarlo EF, Bullough PG. The prevalence and clinicopathological appearance of extension of osteonecrosis in the femoral head. J Bone Joint Surg Br. 1999;81:328–32. 4. Ikemura S, Yamamoto T, Motomura G, Nakashima Y, Mawatari T, Iwamoto Y. MRI evaluation of collapsed femoral head in patients 60 years old or older: differentiation of subchondral insufficiency fracture from osteonecrosis of the femoral head. Am J Roentgenol. 2010;195:W63–8. 5. Nikolopoulos KE, Papadakis SA, Kateros KT, et al. Long-term outcome of patients with avascular necrosis, after internal fixation of femoral neck fractures. Injury. 2003;34:525–8. 6. Asnis SE, Wanek-Sgaglione L. Intracapsular fractures of the femoral neck. Results of cannulated screw fixation. J Bone Joint Surg Am. 1994;76:1793–803. 7. Rodriguez-Merchan EC. In situ fixation of nondisplaced intracapsular fractures of the proximal femur. Clin Orthop Relat Res. 2002;399:42–51. 8. Catto M. A histological study of avascular necrosis of the femoral head after transcervical fracture. J Bone Joint Surg Br. 1965;47: 749–76. 9. Catto M. The histological appearance of late segmental collapse of the femoral head after transcervical fracture. J Bone Joint Surg Br. 1965;47:777–91. 10. Bangil M, Soubrier M, Dubost JJ, et al. Subchondral insufficiency fracture of the femoral head. Rev Rhum Engl Ed. 1996;63:859–61. 11. Yamamoto T, Bullough PG. Subchondral insufficiency fracture of the femoral head: a differential diagnosis in acute onset of coxarthrosis in the elderly. Arthritis Rheum. 1999;42:2719–23. 12. Rafil M, Mitnick H, Klug J, Firooznia H. Insufficiency fracture of the femoral head: MRI imaging in three patients. Am J Roentgenol. 1997;168:159–63. 13. Garden RS. Low-angle fixation in fractures of the femoral head. J Bone Joint Surg Br. 1961;43:647–63. 14. Lu-Yao GL, Keller RB, Littenberg B, Wennberg JE. Outcomes after displaced fractures of the femoral neck. A meta-analysis of one hundred and six published reports. J Bone Joint Surg Am. 1994;76: 15–25. 15. Bachiller FG, Caballer AP, Portal LF. Avascular necrosis of the femoral head after femoral neck fracture. Clin Orthop Relat Res. 2002;399:87–109. 16. Ikemura S, Hara T, Nakamura T, Tsuchiya K. Subchondral insufficiency fracture of the femoral head: a report of two cases with a history of internal fixation of a femoral neck fracture. Skeletal Radiol. 2013;42:849–51. 17. Yamamoto T, Bullough PG. The role of subchondral insufficiency fracture in rapid destruction of the hip joint: a preliminary report. Arthritis Rheum. 2000;43:2423–7.
CASE REPORT
Subchondral insufficiency fracture of the femoral head after internal fixation for femoral neck fracture: histopathological investigation Kazuhiko Sonoda & Takuaki Yamamoto & Goro Motomura & Hidehiko Kido & Yukihide Iwamoto
Received: 23 November 2013 / Revised: 16 January 2014 / Accepted: 21 January 2014 # ISS 2014
Abstract Late segmental collapse after internal fixation for femoral neck fracture is the phenomenon observed in posttraumatic osteonecrosis of the femoral head (ON), which has generally been reported to occur over a year or more after internal fixation. Subchondral insufficiency fracture of the femoral head (SIF) has also been recognized to cause femoral head collapse, however, only two cases of SIF after internal fixation for femoral neck fracture have been reported. We report a case with femoral head collapse observed 5 months after internal fixation for femoral neck fracture, which was histopathologically diagnosed as SIF. Clinically, differentiating SIF from ON is important because some cases of SIF have been reported to heal without surgical treatments. The timing of femoral head collapse after femoral neck fracture may be different between SIF and post-traumatic ON.
which is quite different from what occurs in osteonecrosis of the femoral head (ON) [2]. In ON, zone formation, comprising necrotic, reparative, and normal zone, is a characteristic appearance [3]. However, due to the similar radiographic findings with ON, several cases of SIF previously had been considered as ON [1, 2, 4]. Post-traumatic ON is well recognized as one of the major complications after femoral neck fracture [5–7]. In general, a “late segmental collapse” occurs over a year or more after treatment [8, 9]. Here we report a case that was histopathologically diagnosed as SIF in a patient who developed collapse of the femoral head 5 months after internal fixation for femoral neck fracture. It is important to recognize the occurrence of SIF after femoral neck fracture, since some cases of SIF have been reported to heal without surgical treatments [10–12].
Keywords Subchondral insufficiency fracture . Osteonecrosis of the femoral head . Femoral neck fracture
Case report
Introduction Subchondral insufficiency fracture of the femoral head (SIF) can cause femoral head collapse especially in osteoporotic elderly women [1]. One characteristic histopathological feature in SIF has been reported to be fracture callus formation with associated granulation tissue along the fracture line, K. Sonoda : T. Yamamoto (*) : G. Motomura : Y. Iwamoto Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City 812-8582, Japan e-mail: [email protected] H. Kido Department of Orthopaedic Surgery, Yamaguchi Red Cross Hospital, 53-1 Yahatababa, Yamaguchi City 753-8519, Japan
A 70-year-old female (height: 161 cm, weight: 56.0 kg, body mass index: 21.6) fractured her right femoral neck (Garden I) [13] when she fell down (Fig. 1a, b). She underwent internal fixation with two hook pins (Fig. 1c, d). The day after the operation, she started a rehabilitation program that allowed full weight bearing. Her right hip pain gradually decreased. One month after the operation, she was able to walk without a cane. Four months after the operation, her activity level recovered and she was able to complete activities of daily living without difficulty. The radiographs demonstrated a sclerotic change around the femoral neck without any evidence of femoral head collapse (Fig. 1e, f). Four and a half months after the operation, however, she experienced right hip pain suddenly after standing up from a chair. The radiographs taken 5 months after the operation demonstrated a collapse in the anterior portion of the right femoral head with associated joint space narrowing (Fig. 1g, h). Because of a severe dysfunction
Skeletal Radiol
Fig. 1 A 70-year-old female with right hip pain following a fall. a, b Anteroposterior (a) and lateral (b) radiographs of the right hip at the initial examination show femoral neck fracture (arrows). The fracture is valgus impacted type (Garden I). c, d Anteroposterior (c) and frog leg lateral (d) radiographs at the time of surgery. In situ fixation was performed using two hook pins, since this type of fracture is considered to be stable with lowest risk of developing osteonecrosis. e, f Follow-up anteroposterior (e) and frog leg lateral
(f) radiographs 4 months after internal fixation. At this time, there was no pain in the right hip. Sclerosis (arrows) around a fracture line is seen without any abnormality in the subchondral area. g, h Follow-up anteroposterior (g) and frog leg lateral (h) radiographs 5 months after internal fixation (there was right hip pain). Femoral head collapse is observed in the anterior portion (arrows) and joint space narrowing is also seen at the superior portion of the femoral head (arrowheads)
of the right hip joint, she underwent total hip arthroplasty. Post-traumatic ON was considered; however, the timing of femoral head collapse was relatively early. In order to confirm the diagnosis, histological examination was performed. Sagittal-cut section of the removed femoral head showed a whitish gray zone in the bone marrow space beneath the subchondral plate (Fig. 2a). The articular cartilage was detached from the anterior portion of the femoral head. Microscopically, a subchondral fracture line was observed (Fig. 2b). Fracture callus formation with associated granulation tissue were seen along the fracture line (Fig. 2c). Although small segments of the necrotic bone trabeculae were scattered along the fracture line, there was no evidence of antecedent bone infarction. Based on these histopathological findings, she was diagnosed as SIF.
Discussion Post-traumatic ON is well recognized as a major complication after femoral neck fracture [5–7], and previous reports showed the rate of development to be 20–30 % [14, 15]. Therefore, cases undergoing femoral head collapse after femoral neck fracture are likely to be diagnosed as post-traumatic ON. However, a recent paper reported the occurrence of SIF after femoral neck fracture based on magnetic resonance imaging (MRI) [16]. The current report, for the first time, presents histopathologic evidence of SIF after femoral neck fracture. In recent years, SIF has been recognized as an important differential diagnosis in cases showing femoral head collapse, especially in elderly women [1, 2, 4]. Several studies demonstrated that the shape of the low intensity band on T1-
Fig. 2 Histopathologic findings of the removed femoral head. a Sagittal section of the removed femoral head shows a subchondral fracture, and an irregular whitish gray zone is seen beneath the subchondral plate (arrowheads). b Full cut section of the removed femoral head. A subchondral fracture is seen in the anterior
portion (arrowheads). c This picture is obtained from the area pointed out as “c” in Fig. 2a and b. Fracture callus formation (arrows) with associated granulation tissue (arrowheads) are seen in the bone marrow space around the fracture line (hematoxylin and eosin× 40)
Skeletal Radiol
weighted MRI images is useful in differentiating SIF from ON [2, 11]. However, in patients undergoing internal fixation for femoral neck fracture, it is often difficult to obtain precise MRI images due to the implants. Based on MRI, Ikemura et al. reported two cases of SIF after removal of the implants in relatively younger age (26 and 43-year-old female) [16]. Radiographically, one case showed spherical femoral head with patchy areas of osteosclerosis, while another case showed no abnormality. On the other hand, the current case (70-year-old female) showed progressed femoral head collapse with associated joint space narrowing at a half month after the onset. Bone fragility due to the elderly age might have affected such a rapid progression of collapse [17]. Clinically, femoral head collapse caused by post-traumatic ON usually occurs over a year or more after internal fixation [8, 9]. On the other hand, in our case, femoral head collapse in conjunction with joint space narrowing was observed 5 months after the operation, which seems to be early compared with the typical onset of late segmental collapse in posttraumatic ON. We speculate that the timing of collapse after femoral neck fracture may be different between SIF and posttraumatic ON. SIF should be considered as one of the differential diagnoses for post-traumatic ON after internal fixation for femoral neck fracture. Acknowledgement This work was supported in part by a Grant-in-Aid for Scientific Research (No.24592266) from the Japan Society for the Promotion of Science and a Research Grant for Intractable Diseases from the Ministry of Health and Welfare of Japan. Conflict of interest The authors declare that they have no conflicts of interest.
References 1. Yamamoto T, Iwamoto Y, Schneider R, Bullough PG. Histopathological prevalence of subchondral insufficiency fracture of the femoral head. Ann Rheum Dis. 2008;67:150–3.
2. Yamamoto T, Schneider R, Bullough PG. Insufficiency subchondral fracture of the femoral head. Am J Surg Pathol. 2000;24:464–8. 3. Yamamoto T, DiCarlo EF, Bullough PG. The prevalence and clinicopathological appearance of extension of osteonecrosis in the femoral head. J Bone Joint Surg Br. 1999;81:328–32. 4. Ikemura S, Yamamoto T, Motomura G, Nakashima Y, Mawatari T, Iwamoto Y. MRI evaluation of collapsed femoral head in patients 60 years old or older: differentiation of subchondral insufficiency fracture from osteonecrosis of the femoral head. Am J Roentgenol. 2010;195:W63–8. 5. Nikolopoulos KE, Papadakis SA, Kateros KT, et al. Long-term outcome of patients with avascular necrosis, after internal fixation of femoral neck fractures. Injury. 2003;34:525–8. 6. Asnis SE, Wanek-Sgaglione L. Intracapsular fractures of the femoral neck. Results of cannulated screw fixation. J Bone Joint Surg Am. 1994;76:1793–803. 7. Rodriguez-Merchan EC. In situ fixation of nondisplaced intracapsular fractures of the proximal femur. Clin Orthop Relat Res. 2002;399:42–51. 8. Catto M. A histological study of avascular necrosis of the femoral head after transcervical fracture. J Bone Joint Surg Br. 1965;47: 749–76. 9. Catto M. The histological appearance of late segmental collapse of the femoral head after transcervical fracture. J Bone Joint Surg Br. 1965;47:777–91. 10. Bangil M, Soubrier M, Dubost JJ, et al. Subchondral insufficiency fracture of the femoral head. Rev Rhum Engl Ed. 1996;63:859–61. 11. Yamamoto T, Bullough PG. Subchondral insufficiency fracture of the femoral head: a differential diagnosis in acute onset of coxarthrosis in the elderly. Arthritis Rheum. 1999;42:2719–23. 12. Rafil M, Mitnick H, Klug J, Firooznia H. Insufficiency fracture of the femoral head: MRI imaging in three patients. Am J Roentgenol. 1997;168:159–63. 13. Garden RS. Low-angle fixation in fractures of the femoral head. J Bone Joint Surg Br. 1961;43:647–63. 14. Lu-Yao GL, Keller RB, Littenberg B, Wennberg JE. Outcomes after displaced fractures of the femoral neck. A meta-analysis of one hundred and six published reports. J Bone Joint Surg Am. 1994;76: 15–25. 15. Bachiller FG, Caballer AP, Portal LF. Avascular necrosis of the femoral head after femoral neck fracture. Clin Orthop Relat Res. 2002;399:87–109. 16. Ikemura S, Hara T, Nakamura T, Tsuchiya K. Subchondral insufficiency fracture of the femoral head: a report of two cases with a history of internal fixation of a femoral neck fracture. Skeletal Radiol. 2013;42:849–51. 17. Yamamoto T, Bullough PG. The role of subchondral insufficiency fracture in rapid destruction of the hip joint: a preliminary report. Arthritis Rheum. 2000;43:2423–7.
