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(Radiology. 1999;211:237-240.)
© RSNA, 1999

Musculoskeletal Imaging

Incomplete Intertrochanteric Fractures: Imaging Features and Clinical Management1

Elizabeth Schultz, MD, Theodore T. Miller, MD, Scott D. Boruchov, MD, Eric B. Schmell, MD and Baruch Toledano, MD

1 From the Department of Radiology (E.S., T.T.M., S.D.B., E.B.S.) and Division of Orthopedic Surgery (B.T.), North Shore University Hospital, 300 Community Dr, Manhasset, NY 11030, and North Shore Radiology, Great Neck, NY (T.T.M.). From the 1997 RSNA scientific assembly. Received May 14, 1998; revision requested July 6; revision received August 17; accepted October 17. Address reprint requests to E.S.


   Abstract
TOP
 Abstract
Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
PURPOSE: To present the imaging findings and treatment options for incomplete intertrochanteric fractures.

MATERIALS AND METHODS: Among 31 patients with the magnetic resonance (MR) imaging diagnosis of incomplete intertrochanteric fracture, 30 also underwent radiography. MR and radiographic findings were compared. Note was made of fracture length and extent as depicted on the coronal and axial MR images, treatment (surgical vs conservative), and follow-up.

RESULTS: Correlation between radiographic and MR findings was poor. Incomplete intertrochanteric fracture was the prospective radiographic diagnosis in only one case. Fracture in 18 patients was treated surgically and in 13 was managed conservatively. In both groups, the average age of the patients and length of the fractures and the percentage of separate fractures involving the greater trochanter and crossing the midline of the femur in the axial plane were the same. Fractures crossed the midline in the coronal plane in 50% of the surgical group but in only 23% of the nonsurgical group. Average time from injury to ambulation was 2 days less in the surgical group, but no difference in functional status was found subjectively between the two groups at clinical follow-up.

CONCLUSION: Incomplete intertrochanteric fractures are a previously unrecognized subset of intertrochanteric fractures that are diagnosed unequivocally only with MR imaging.

Index terms: Femur, fractures, 443.411 • Femur, MR, 443.121411, 443.121415 • Hip, fractures, 443.411 • Hip, MR, 443.121411, 443.121415


   Introduction
TOP
 Abstract
 Introduction
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
Radiographically occult fractures, particularly those involving the hip and pelvis, are readily demonstrated with magnetic resonance (MR) imaging (1–3). In the MR imaging evaluation of clinically suspected hip fractures, we have observed patients with a fracture of the intertrochanteric region of the hip that does not meet the criteria for conventional intertrochanteric fractures; the fracture emanates from the greater trochanter and extends into the intertrochanteric region but does not disrupt the medial cortex. We refer to this injury as an "incomplete intertrochanteric fracture." Radiographically, this fracture is either occult or misinterpreted as a fracture of only the greater trochanter.

Tronzo (4) included this injury in his classification of intertrochanteric fractures in 1974, but other classification systems for intertrochanteric fractures do not include the incomplete type (5–8). Widespread use of MR imaging to evaluate hip fractures has demonstrated different types of radiographically occult fractures and anecdotal reports of incomplete intertrochanteric fractures (3,9). The purpose of this study was to describe incomplete intertrochanteric fractures as a distinct entity and discuss management.


   MATERIALS AND METHODS
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 References
 
Patients
Between July 1, 1992, and January 31, 1998, 312 patients with clinically suspected hip fracture were seen in our emergency department, and each underwent MR examination of the hip. In 29 of these patients, the MR imaging diagnosis was incomplete intertrochanteric fracture. Two additional patients who were not in the emergency room population, one with metastatic prostate cancer who was suspected of having a pathologic hip fracture and one with hip pain thought to be due to avascular necrosis of the femoral head, also underwent MR imaging and were found to have incomplete intertrochanteric fractures. These 31 patients (22 women and nine men; age range, 65–96 years; mean age, 82 years) compose our study population.

MR Imaging Studies
The MR imaging examinations of the 29 patients seen in the emergency room were obtained within an average of 1.7 days (range, 4 hours to 8 days) after presentation. All MR imaging examinations were performed on 1.5-T units (Signa; GE Medical Systems, Milwaukee, Wis), with a body coil in 29 cases and a phased array pelvic coil in two. All 31 patients underwent imaging in the coronal or oblique coronal plane with a conventional spin-echo T1-weighted sequence (repetition time msec/echo time msec = 400–700/10–18, 24–38-cm field of view, 3–6-mm section thickness with no intersection gap, a 256 x 192–256 matrix, and one to four signals acquired) and a frequency selective fat-suppressed fast spin-echo T2-weighted sequence (3,000–5,000/48–108, 20–38-cm field of view, 3–7-mm section thickness with 0–1-mm intersection gap, 256 x 192–256 matrix, two to four signals acquired, and echo train length of eight to 16). Twenty-three patients also underwent conventional spin-echo T1-weighted imaging in the axial plane (400–700/10–17, 20–40-cm field of view, 4–6-mm section thickness with 0–1-mm intersection gap, 256 x 160–192 matrix, and one and one-half to four signals acquired), and 28 patients underwent imaging in the axial plane with a frequency-selective fat-suppressed fast spin-echo T2-weighted sequence (4,000–5,000/45–102, 20–32-cm field of view, 4–6-mm section thickness with a 0–1-mm intersection gap, 256 x 192–256 matrix, two to three signals acquired, and echo train length of eight to 16). In three cases, axial imaging was not performed because the patients could not tolerate further imaging after the coronal acquisition.

Evaluation of Images
In consensus, two musculoskeletal radiologists (E.S., T.T.M.) retrospectively reviewed the coronal and, when available, axial T1-weighted images to determine the extent of fracture. The T1-weighted images were reviewed because of the better signal-to-noise ratio and anatomic resolution they provided compared with those for the T2-weighted images. In cases in which no axial T1-weighted images were available, the T2-weighted axial images were used. The coronal T2-weighted images were reviewed to determine the presence of a bone marrow edema pattern adjacent to the fracture.

The two radiologists evaluated fracture length and medial and anterior extent. The fracture appeared as a linear or serpiginous area of low signal intensity on images obtained with all pulse sequences. Fracture length was determined by drawing a line from the proximal aspect of the fracture to its distal end. A "best fit" straight line measurement was made if the fracture line itself was curved. When an avulsion fracture of the greater trochanter was present, the measurement was begun at the base of the greater trochanter. Medial and anterior extents were assessed in the coronal and axial planes, respectively, by determining if the fracture crossed the midline of the femoral shaft (Fig 1).



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  		Figure 1. Normal hip. On coronal (left) and axial (right) T1-weighted images (500/15), the line bisects the femoral shaft. The rulers indicate centimeters.

 
The two radiologists retrospectively reviewed the original radiographs and interpretations for the hips of the 29 patients obtained at the time of presentation to the emergency room; they correlated these findings with those on the MR images. The radiographs and interpretations for the patient believed to have a pathologic fracture were also reviewed. No radiographs were available for the patient who was suspected of having avascular necrosis of the femoral head.


   RESULTS
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 References
 
Among the 29 emergency room patients, radiographs for 16 were prospectively interpreted as depicting no fracture (Fig 2); for 10, fracture confined to the greater trochanter; one, conventional intertrochanteric fracture; one, possible subtrochanteric fracture; and one, incomplete intertrochanteric fracture. Radiographs for the patient with metastatic prostate cancer were prospectively interpreted as normal. None of the radiographic interpretations were altered after retrospective analysis of the radiographs with the knowledge that an incomplete intertrochanteric fracture was documented at MR imaging.



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  		Figure 2a. Incomplete intertrochanteric fracture in an 83-year-old woman. (a) Anteroposterior radiograph of the right hip shows no fracture. (b) Coronal T1-weighted MR image (500/11) shows a serpiginous intertrochanteric fracture (arrows) that reaches the midline. (c) Coronal fat-suppressed fast spin-echo T2-weighted MR image (4,000/90; echo train length, 16) at a slightly different level shows ill-defined high-signal-intensity marrow edema (arrows). The patient was treated conservatively. The time from injury to ambulation is not known, but she was in good condition at 31/2-year follow-up.

 


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  		Figure 2b. Incomplete intertrochanteric fracture in an 83-year-old woman. (a) Anteroposterior radiograph of the right hip shows no fracture. (b) Coronal T1-weighted MR image (500/11) shows a serpiginous intertrochanteric fracture (arrows) that reaches the midline. (c) Coronal fat-suppressed fast spin-echo T2-weighted MR image (4,000/90; echo train length, 16) at a slightly different level shows ill-defined high-signal-intensity marrow edema (arrows). The patient was treated conservatively. The time from injury to ambulation is not known, but she was in good condition at 31/2-year follow-up.

 


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  		Figure 2c. Incomplete intertrochanteric fracture in an 83-year-old woman. (a) Anteroposterior radiograph of the right hip shows no fracture. (b) Coronal T1-weighted MR image (500/11) shows a serpiginous intertrochanteric fracture (arrows) that reaches the midline. (c) Coronal fat-suppressed fast spin-echo T2-weighted MR image (4,000/90; echo train length, 16) at a slightly different level shows ill-defined high-signal-intensity marrow edema (arrows). The patient was treated conservatively. The time from injury to ambulation is not known, but she was in good condition at 31/2-year follow-up.

 
Characteristics of the fractures are presented in Table 1. As measured in the coronal plane, the length of the fractures varied from 2.5 to 9.5 cm. In the coronal plane, 19 of 31 fractures (61%) did not reach the midline of the femoral shaft (Fig 3) and 12 (39%) either reached or crossed the midline to the medial side of the proximal femoral shaft. On all 28 available axial images, the fracture crossed the midline to extend into the anterior half of the femoral shaft without breaching the anterior cortex. A separate fracture of the greater trochanter was seen in 19 of the 31 cases (61%); 12 of these fractures were comminuted. On all 31 T2-weighted images, a bone marrow edema pattern, consisting of ill-defined increased signal intensity in the region of the fracture, confirmed the acute nature of these fractures (Fig 2).


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  		TABLE 1. Intertrochanteric Fracture Characteristics
 


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  		Figure 3a. Incomplete intertrochanteric fracture in an 87-year-old woman. (a) Coronal T1-weighted MR image (500/11) shows an intertrochanteric fracture (arrows) that does not cross the midline. (b) Axial T1-weighted MR image (550/16) shows the fracture (arrows) crossing the midline. The patient was treated conservatively. The time from injury to ambulation was 6 days, and she was doing well at 2-month follow-up.

 


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  		Figure 3b. Incomplete intertrochanteric fracture in an 87-year-old woman. (a) Coronal T1-weighted MR image (500/11) shows an intertrochanteric fracture (arrows) that does not cross the midline. (b) Axial T1-weighted MR image (550/16) shows the fracture (arrows) crossing the midline. The patient was treated conservatively. The time from injury to ambulation was 6 days, and she was doing well at 2-month follow-up.

 
Fracture in 18 patients (58%) was treated surgically with a sliding compression screw and in 13 (42%) was treated conservatively. Patients in each group were similar with respect to age, fracture length, associated separate fracture of the greater trochanter, and extent of the fracture to or beyond the midline of the femoral shaft in the axial plane (Table 1). The only difference between the two groups was the midline extent of the fracture in the coronal plane. Fifteen orthopedic surgeons were involved in the care or treatment of the 31 patients.

The average time from injury to surgery was 2.5 days (range, 1–6 days) and was dependent on the presence of coexistent medical conditions, such as cardiac or pulmonary disease, that needed to be treated in order to obtain medical clearance for surgery. The length of time from injury to ambulation was available for 23 patients (Table 2). Follow-up was available for 12 patients (range, 2 months to 31/2 years); the condition of patients in both groups was subjectively rated as good by their clinicians.


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  		TABLE 2. Patient Data
 

   DISCUSSION
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
References
 
Various classification systems for hip fractures are based on anatomic location, fracture plane, degree of displacement, and angulation (4–8). The purpose of these classification systems is to guide treatment and facilitate comparison of treatment results (10).

The Evans classification system (5), devised in 1949, divides intertrochanteric fractures into two main types based on stability. The Jensen classification system (7), which modified the Evans system, describes a type 1 fracture as a nondisplaced two-part fracture; type 2, displaced two-part fracture; type 3, three-part fracture with displacement of the greater trochanter; type 4, three-part fracture with displacement of the calcar and lesser trochanter; and type 5, displaced four-part fracture. The Boyd and Griffin classification system (6), based on displacement and comminution of the involved fragments, was later modified by Tronzo (4) to incorporate the type of reduction needed. As cited by Boeck (8), Ender based his system on the mechanism of fracture. Only the Tronzo system described incomplete intertrochanteric fractures.

The possibility of incomplete fracture is known, such as a Garden stage 1 fracture of the subcapital portion of the femoral neck (11). In a Garden stage 1 fracture, the lateral cortex is disrupted while the medial side remains intact, which is similar to what we describe as an incomplete intertrochanteric fracture. In our series, none of the incomplete fractures emanated from the medial femoral cortex. This suggests that a complete intertrochanteric fracture begins superolaterally and propagates anteriorly and inferomedially.

The fracture we describe occurs in the same population as do conventional hip fractures, that is, the elderly population with a female preponderance. In our patient population, the mean age was 82 years and the majority were women; therefore, it is reasonable to assume that osteoporosis with subsequent insufficiency is a predisposing factor, as with conventional hip fractures. All but two of our patients had a history of trauma and were enrolled after presentation in the emergency room.

The diagnosis of incomplete intertrochanteric fracture is established definitively only with MR imaging. In our series, the radiographic diagnosis was suspected prospectively in only one case. The entire fracture was radiographically occult in half of our cases, whereas it was thought to be confined to the greater trochanter in almost a third.

Unlike Garden stage 1 fractures, for which the standard of care is surgical pinning, no criteria have been established to guide treatment of incomplete intertrochanteric fractures. Although the length of fracture, the presence of a separate fracture of the greater trochanter, and the extent of the fracture in the axial plane were similar between our surgical and nonsurgical patients, there was a difference in treatment for those with fractures that crossed the midline in the coronal plane. Fifty percent of the surgical patients had fractures that crossed the midline in the coronal plane, whereas only 23% of the nonsurgical patients had such fractures. In his decision to perform surgery, one of the authors (B.T.) uses features of an incomplete intertrochanteric fracture such as extension across the midline in the coronal plane or a course of fracture in a true intertrochanteric plane. Surgery for an incomplete intertrochanteric fracture is prophylactic because of the risk of progression to a complete fracture that results from the high biomechanical stresses along the medial portion of the femur. Fifteen orthopedic surgeons were involved in the care of our 31 patients, and there was no uniform treatment protocol. The decision to perform surgery was also affected by the presence of other medical conditions.

If one nonsurgical patient with an injury-to-ambulation time of 25 days is excluded from analysis, then the time in both groups was 7 days. However, if patients in the surgical group had undergone surgery the day they presented to the emergency room, the time difference between the two groups would have been approximately 2 days. This potential time difference has implications for length of hospitalization. In the nonsurgical group, the longer time from injury to MR imaging might have been due to the patients being sicker or to their having a lower clinical suspicion for hip fracture. These two factors might have delayed evaluation with MR imaging, and the former might have favored conservative treatment and resulted in a longer time to ambulation. No difference was found in the functional status between the two groups at follow-up, as subjectively assessed by their clinicians.

One weakness of this study is the inability to determine the frequency of incomplete intertrochanteric fractures. Patients with incomplete intertrochanteric fracture but normal radiographs and low clinical suspicion would not have undergone MR imaging. Pain in patients with radiographic evidence of only a greater trochanteric fracture would have been attributed to that fracture, and they would not have undergone MR imaging. In addition, we may have missed some cases in our review of reports of hip fractures if the diagnosis was not specifically worded as "incomplete intertrochanteric fracture." Other weaknesses are that our series of 31 cases is too small to allow establishment of definitive criteria for the management of incomplete intertrochanteric fractures and that the follow-up involved only 12 patients. The remainder of the patients were lost to orthopedic follow-up because they failed to return to their orthopedic surgeon, moved away, were admitted to nursing homes owing to concomitant medical conditions, or died of causes unrelated to their fracture.

In conclusion, incomplete intertrochanteric fractures are a distinct subtype of intertrochanteric fractures that can be diagnosed with certainty only with MR imaging. Precise delineation is essential to ensure proper treatment. Incomplete intertrochanteric fractures that do not cross the midline may be treated conservatively, whereas those that cross the midline tend to be treated surgically. Complete intertrochanteric fractures require surgical treatment with a compression screw. We propose that incomplete intertrochanteric fractures be incorporated into the classification systems for hip fractures.


   Acknowledgments
 
The authors thank Lorraine White and Lauri Schoenfeld for their help in preparing the manuscript for this article.


   Footnotes
 
Author contributions: Guarantors of integrity of entire study, E.S., T.T.M.; study concepts and design, E.S., T.T.M.; definition of intellectual content, E.S., T.T.M.; literature research, E.S.; data acquisition, S.D.B., E.B.S., E.S.; data analysis, E.S.; manuscript preparation, E.S., T.T.M., B.T.; manuscript editing and review, E.S., T.T.M.


   References
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 

  1. Yao L, Lee JK. Occult intraosseous fracture: detection with MR imaging. Radiology 1988; 167:749-751.[Abstract/Free Full Text]
  2. Deutsch AL, Mink JH, Wasman AD. Occult fractures of the proximal femur: MR imaging. Radiology 1989; 170:113-116.[Abstract/Free Full Text]
  3. Rizzo PF, Gould ES, Lyden JP, Asnis SE. Diagnosis of occult fractures about the hip. J Bone Joint Surg [Am] 1993; 75:395-401.[Abstract/Free Full Text]
  4. Tronzo RG. Symposium on fractures of the hip. I. Special considerations in management. Orthop Clin North Am 1974; 5:571-583.
  5. Evans EM. The treatment of trochanteric fractures of the femur. J Bone Joint Surg [Br] 1949; 31:191-203.
  6. Boyd HB, Griffin LL. Classification and treatment of trochanteric fractures. Arch Surg 1949; 58:853-866.[Abstract/Free Full Text]
  7. Jensen JS. Classification of trochanteric fractures. Acta Orthop Scand 1980; 51:803-810.[Medline]
  8. Boeck HD. Classification of hip fractures. Acta Orthop Belg 1994; 60:106-109.
  9. Rogers LF. The hip and femoral shaft. In: Rogers LF, eds. Radiology of skeletal trauma. 2nd ed. New York, NY: Livingstone, 1992; 1141.
  10. Steinberg GG, Desal SS, Kronwitz NA, Sullivan TJ. The intertrochanteric hip fractures: a retrospective analysis. Orthopedics 1988; 11:265-273.[Medline]
  11. Garden RS. Low-angle fixation in fractures of the femoral neck. J Bone Joint Surg [Br] 1961; 43:647-663.



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