Predictors and Reduction Techniques for Irreducible Reverse Intertrochanteric Fractures

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Predictors and Reduction Techniques for Irreducible Reverse Intertrochanteric Fractures

Reverse intertrochanteric fractures, classified as AO Foundation/Orthopaedic Trauma Association (AO/OTA) 31-A3, are complex fractures with a major fracture line running from distolateral to proximomedial. These fractures are inherently unstable due to their unique anatomic and mechanical characteristics, making them challenging to manage. While most trochanteric fractures are initially treated with closed reduction and internal fixation, a significant proportion of reverse intertrochanteric fractures are irreducible and require open reduction. This article provides a comprehensive overview of the predictors, displacement patterns, and reduction techniques for irreducible reverse intertrochanteric fractures based on a retrospective study of 113 cases.

Background and Significance

Trochanteric fractures are increasingly common in the aging population and are typically managed surgically. Closed reduction and internal fixation are the standard approaches, but some fractures, particularly reverse intertrochanteric fractures, are difficult to reduce through closed manipulation. These irreducible fractures often necessitate open reduction to achieve satisfactory alignment and stability. Despite the clinical importance of these fractures, there is limited research on the predictors of irreducibility and the specific reduction techniques required for different displacement patterns. This study aims to fill this gap by analyzing the radiographic features, displacement patterns, and reduction strategies for irreducible reverse intertrochanteric fractures.

Methods

The study retrospectively reviewed 1174 cases of trochanteric fractures treated between January 2006 and October 2018, of which 113 were reverse intertrochanteric fractures. Irreducible fractures were defined based on intra-operative fluoroscopy imaging after closed manipulation. The reduction quality was evaluated using criteria proposed by Baumgaertner and Solberg, which assess neck-shaft alignment and displacement on anteroposterior (AP) and lateral views. A “good” reduction met all alignment and displacement criteria, while “acceptable” and “poor” reductions did not.

Patient demographics, clinical characteristics, and radiological parameters were recorded, including age, gender, body mass index (BMI), AO/OTA classification, fracture line type, lesser trochanter status, lateral femoral wall status, and femoral shaft displacement relative to the head-neck fragment. For irreducible fractures, the displacement patterns after closed manipulation, reduction techniques, and final reduction quality were documented.

Results

Incidence and Demographics

Of the 113 reverse intertrochanteric fractures, 76 (67%) were irreducible. The average age of patients with irreducible fractures was 68.1 years, with 34 males and 42 females. The majority of irreducible fractures were classified as AO/OTA 31-A3.3 (60 cases), followed by 31-A3.1 (8 cases) and 31-A3.2 (8 cases). Low-energy mechanisms (e.g., falls from standing height) accounted for 54 cases, while high-energy mechanisms (e.g., car accidents or falls from a height) accounted for 22 cases.

Displacement Patterns

Six distinct patterns of displacement were identified in irreducible reverse intertrochanteric fractures:

  1. Medial Displacement and Posterior Sagging of the Femoral Shaft Relative to the Head-Neck Fragment: This was the most common pattern, observed in 30 patients. The femoral shaft was medially displaced on the AP view and sagged posteriorly on the lateral view. A bone hook was used to pull the femoral shaft laterally, and a mallet was used to elevate the shaft.

  2. Posterior Sagging of the Femoral Shaft Relative to the Head-Neck Fragment: Observed in 11 patients, this pattern showed posterior sagging on the lateral view despite good alignment on the AP view. A Schanz screw was used as a joystick to reduce the fracture, followed by fixation with a locking compression plate.

  3. Malalignment of the Lateral Femoral Wall: This pattern, seen in 11 patients, involved a displaced lateral femoral wall despite good contact of the medial and anterior cortices. K-wires were used to reduce and provisionally fix the lateral wall, followed by intra-medullary fixation.

  4. Separation of the Lateral Femoral Wall on the Sagittal Plane: Observed in 9 patients, this pattern involved a coronal fracture line of the lateral femoral wall. A clamp and cannulated screws were used to reduce and fix the fragments, followed by a locking compression plate.

  5. Lateral Displacement and Posterior Sagging of the Femoral Shaft Relative to the Head-Neck Fragment: This pattern, seen in 9 patients, involved lateral displacement on the AP view and posterior sagging on the lateral view. A periosteum elevator and mallet were used to reduce the fracture.

  6. Medially Displaced Femoral Shaft Relative to the Head-Neck Fragment: Observed in 6 patients, this pattern involved medial displacement on the AP view with good alignment on the lateral view. A bone hook was used to pull the femoral shaft laterally.

Reduction Techniques

Various reduction techniques were employed based on the displacement pattern:

  • Bone Hook: Used to pull the femoral shaft laterally in patterns involving medial displacement.
  • Mallet: Used to elevate the femoral shaft in patterns involving posterior sagging.
  • Schanz Screw: Used as a joystick to reduce posterior sagging in cases where precise control was needed.
  • Clamp and Cannulated Screws: Used to reduce and fix separated lateral femoral wall fragments.
  • Periosteum Elevator: Used to push the head-neck fragment posteriorly in cases of lateral displacement.

Reduction Quality and Follow-Up

After applying the reduction techniques, 53 cases (70%) achieved good reduction quality, 15 cases (20%) had acceptable reduction quality, and 8 cases (11%) had poor reduction quality. Implant failure occurred in 10 patients (13%), with higher rates observed in cases with poor reduction quality.

Predictors of Irreducibility

Multivariate logistic regression analysis identified three predictors of irreducibility:

  1. Medially Displaced Femoral Shaft Relative to the Head-Neck Fragment on the AP View (Odds Ratio [OR], 8.00; 95% Confidence Interval [CI], 3.04–21.04; P < 0.001): This displacement pattern was strongly associated with irreducibility, likely due to the function of the adductor muscles.

  2. Displaced Lesser Trochanter (OR, 3.61; 95% CI, 1.35–9.61; P = 0.010): A displaced lesser trochanter indicates loss of control over the femoral shaft by the iliopsoas and gluteus minimus, leading to posterior sagging.

  3. Displaced Lateral Femoral Wall (OR, 2.92; 95% CI, 1.02–8.34; P = 0.046): A comminuted lateral femoral wall complicates reduction and increases the risk of irreducibility.

Discussion

Reverse intertrochanteric fractures pose unique challenges due to their instability and complex displacement patterns. This study highlights that a significant proportion of these fractures are irreducible, necessitating open reduction and specialized techniques. The identification of specific displacement patterns and corresponding reduction strategies provides valuable guidance for surgeons.

The most common displacement pattern, medial displacement and posterior sagging of the femoral shaft, underscores the importance of addressing both coronal and sagittal plane deformities. Techniques such as using a bone hook and mallet are effective in achieving reduction in these cases. Similarly, the use of a Schanz screw as a joystick offers precise control in reducing posterior sagging, particularly when traditional methods are insufficient.

The predictors of irreducibility identified in this study—medial displacement of the femoral shaft, displaced lesser trochanter, and displaced lateral femoral wall—are critical for preoperative planning. Recognizing these factors allows surgeons to anticipate the need for open reduction and prepare accordingly, potentially reducing operative time and improving outcomes.

Despite the advancements in reduction techniques, a subset of fractures (11%) remained poorly reduced, highlighting the complexity of these injuries. These cases often involved re-displacement after fixation, emphasizing the need for meticulous reduction and stable fixation.

Conclusion

This study demonstrates that a high proportion of reverse intertrochanteric fractures are irreducible and require specialized reduction techniques. Six distinct displacement patterns were identified, each necessitating specific reduction strategies. Predictors of irreducibility include medial displacement of the femoral shaft, displaced lesser trochanter, and displaced lateral femoral wall. These findings underscore the importance of preoperative recognition and tailored management to achieve optimal outcomes in these challenging fractures.

doi.org/10.1097/CM9.0000000000000493

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