CT scans better assess lateral wall morphology of "stable appearing" intertrochanteric (IT) femur fractures and predict early failure of sliding hip screw (SHS) fixation

[Research progress on weak state of lateral wall in intertrochanteric fractures]

Objective

To review the research progress of the weak state of the lateral wall in intertrochanteric fracture, in order to provide clinical references.

Methods

The relevant research literature on the lateral wall of intertrochanteric fracture at home and abroad in recent years was summarized and analyzed in terms of morphology, fracture line in coronal plane, and bone density.

Results

Assessment of weak state of the lateral wall is particularly important in the treatment of intertrochanteric fractures. Lateral wall thickness is the main way to assess the weak state of the lateral wall, but there are still problems. Many scholars at home and abroad have studied various aspects such as width, height, and length of the anterior cortex, but there is a lack of a comprehensive assessment method. Coronal fractures affect lateral wall morphology and are difficult to detect on X-ray films, requiring vigilance on the part of the clinician. Further research is needed to clarify the correlation between bone density and the weak state of the lateral wall. The femur lesser trochanter fractures interacts with the latertal wall, and the lesser trochanter fracture exacerbates the weak state. The soft tissue around the lateral wall also affects the weak state, so attention must be paid to protecting the soft tissues during operation.

Conclusion

There are more methods for assessing the weak state of the lateral wall, but none of them has formed a unified standard. Most of the current studies assess the weak state from a single perspective and lack a comprehensive assessment of all aspects affecting the lateral wall. Fewer studies have been conducted to assess the residual lateral wall function after a partial fracture of the lateral wall, and further research is needed.

Accuracy of detecting burst of the lateral wall in intertrochanteric hip fractures with plain radiographs: Is postoperative CT necessary?

Background

Postoperative burst of the lateral femoral wall is thought to be the main predictor of reoperation for intertrochanteric fractures, which is routinely evaluated using plain radiographs. We retrospectively compared computed tomography (CT) scans and radiographs regarding the ability to detect burst of the lateral wall. We also investigated whether intramedullary nails may cause iatrogenic burst of the lateral wall.

Methods

From January 2010 to December 2021, patients aged 65 years and older who undergone intertrochanteric fractures treated with the proximal femoral nail antirotation 2 (PFNA-Ⅱ) were included. The incidence of burst of the lateral wall was evaluated with two different imaging modalities by two observers. Two rounds of evaluation were performed: (1) with plain radiographs alone; and (2) with CT scans combined with radiographs. Interobserver and intraobserver agreement (κ value) for evaluation of the lateral wall burst was assessed.

Results

A total of 1507 patients were included (362 males and 1145 females). Compared with radiographs alone (12.0 %, 181/1507 patients), a higher rate of lateral wall burst was found by CT scans combined with radiographs (72.9 %, 1098/1507 patients) for observer 1 at first reading (P < 0.001). Similar results were seen in other evaluations. Interobserver and intraobserver agreement was substantial for radiographs alone (κ, 0.659-0.727) and almost perfect for CT scans combined with radiographs (κ, 0.847-0.926).

Conclusions

Computed tomography combined with radiographs is superior to radiographs alone for detecting burst of the lateral wall after intertrochanteric fracture fixation. Additionally, PFNA-Ⅱ could cause iatrogenic burst of the lateral wall for intertrochanteric fractures in the elderly.

Relative lateral wall thickness is an improved predictor for postoperative lateral wall fracture after trochanteric femoral fracture osteosynthesis

Lateral wall thickness is a known predictor for postoperative stability of trochanteric femoral fractures and occurrence of secondary lateral wall fractures. Currently, the AO/OTA classification relies on the absolute lateral wall thickness (aLWT) to distinguish between stable A1.3 and unstable A2.1 fractures that does not take interpersonal patient differences into account. Thus, a more individualized and accurate measure would be favorable. Therefore, we proposed and validated a new patient-specific measure-the relative lateral wall thickness (rLWT)-to consider individualized measures and hypothesized its higher sensitivity and specificity compared with aLWT. First, in 146 pelvic radiographs of patients without a trochanteric femoral fracture, the symmetry of both caput-collum-diaphyseal angle (CCD) and total trochanteric thickness (TTT) was assessed to determine whether the contralateral side can be used for rLWT determination. Then, data of 202 patients were re-evaluated to compare rLWT versus previously published aLWT. Bilateral symmetry was found for both CCD and TTT (p ≥ 0.827), implying that bone morphology and geometry of the contralateral intact side could be used to calculate rLWT. Validation revealed increased accuracy of the rLWT compared with the gold standard aLWT, with increased specificity by 3.5% (Number Needed to Treat = 64 patients) and sensitivity by 1% (Number Needed to Treat = 75 patients). The novel rLWT is a more accurate and individualized predictor of secondary lateral wall fractures compared with the standard aLWT. This study established the threshold of 50.5% rLWT as a reference value for predicting fracture stability in trochanteric femoral fractures.