Intraoperative Monitoring of Epiphyseal Perfusion in Slipped Capital Femoral Epiphysis: Surgical Technique

Intraoperative Epiphyseal Perfusion Monitoring Does Not Reliably Predict Osteonecrosis Following Treatment of Unstable SCFE

BACKGROUND

Avascular necrosis (AVN) remains the most dreaded complication of unstable slipped capital femoral epiphysis (SCFE) treatment. Newer closed reduction techniques (with perfusion monitoring) have emerged as a technically straightforward means to address residual SCFE deformity while still minimizing the risk of osteonecrosis. However, limited data exists regarding the reliability of intraoperative epiphyseal perfusion monitoring to predict the development of AVN. The purpose of this study was to evaluate its reliability.

METHODS

We retrospectively reviewed all patients with unstable SCFE who underwent closed or open reduction with epiphyseal perfusion monitoring using an intracranial pressure (ICP) probe from 2015 to 2023 at a single institution with a minimum 6-month radiographic follow-up. Demographic, clinical, and radiographic data were recorded, including duration of symptoms, type of reduction, capsulotomy performed, presence of a waveform on ICP monitoring after epiphyseal fixation, and development of AVN on follow-up radiographs.

RESULTS

Our cohort included 33 hips (32 patients), of which 60.6% (n=20) were male. The average age was 12.5±1.8 years, with a median follow-up of 15.8 months. Eleven hips were treated with open reduction using the modified Dunn technique (10 hips) or anterior approach (1 hip), and 22 hips were treated with inadvertent (5 hips) or purposeful closed reduction using the Leadbetter technique (17 hips). Overall, 8 of the 33 hips in our series (24.2%) developed AVN, 6 of which (20%) had a pulsatile waveform on intraoperative epiphyseal perfusion monitoring. The overall rate of AVN after closed reductions was 31.8% (7 of 22 hips); the incidence of AVN after closed reduction with a detectable waveform was 30% (6 of 20 hips). There was no significant association between time to surgery ( P =0.416) or type of reduction ( P =0.218) and the incidence of AVN.

CONCLUSIONS

In this series, intraoperative epiphyseal perfusion monitoring did not reliably predict the development of osteonecrosis. To our knowledge, this is the first study to report AVN after demonstrable intraoperative epiphyseal perfusion following closed reduction of unstable slips.

LEVEL OF EVIDENCE

Level IV: case series-therapeutic study.

Methods to predict osteonecrosis of femoral head after femoral neck fracture: a systematic review of the literature

BACKGROUND

Femoral neck fracture (FNF) is a very common traumatic disorder and a major cause of blood supply disruption to the femoral head, which may lead to a severe long-term complication, osteonecrosis of femoral head (ONFH). Early prediction and evaluation of ONFH after FNF could facilitate early treatment and may prevent or reverse the development of ONFH. In this review paper, we will review all the prediction methods reported in the previous literature.

METHODS

Studies on the prediction of ONFH after FNF were included in PubMed and MEDLINE databases with articles published before October 2022. Further screening criteria were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. This study highlights all the advantages and disadvantages of the prediction methods.

RESULTS

There were a total of 36 studies included, involving 11 methods to predict ONFH after FNF. Among radiographic imaging, superselective angiography could directly visualize the blood supply of the femoral head, but it is an invasive examination. As noninvasive detection methods, dynamic enhanced magnetic resonance imaging (MRI) and SPECT/CT are easy to operate, have a high sensitivity, and increase specificity. Though still at the early stage of development in clinical studies, micro-CT is a method of highly accurate quantification that can visualize femoral head intraosseous arteries. The prediction model relates to artificial intelligence and is easy to operate, but there is no consensus on the risk factors of ONFH. For the intraoperative methods, most of them are single studies and lack clinical evidence.

CONCLUSION

After reviewing all the prediction methods, we recommend using dynamic enhanced MRI or single photon emission computed tomography/computed tomography in combination with the intraoperative observation of bleeding from the holes of proximal cannulated screws to predict ONFH after FNF. Moreover, micro-CT is a promising imaging technique in clinical practice.

Presence and magnitude of anterior physeal separation in slipped upper femoral epiphysis helps identifying those at high risk for avascular necrosis

AIMS

We sought to determine if the magnitude of anterior physeal separation (APS) in slipped upper femoral epiphysis was a predictor for the subsequent development of avascular necrosis (AVN). Anterior Physeal Separation (APS) is defined as the distance between the anterior lip of the bony capital epiphysis and the lateral corresponding point of the adjacent bony metaphysis on the Lauenstein radiographic view. It represents hinging of the posterior aspect of the metaphysis with the anterior epiphysis lifting away from its adjacent metaphysis, indicating instability and potential vulnerability of the vessels.

PATIENTS AND METHODS

A retrospective review of all patients treated regionally for slipped upper femoral epiphysis over a 9 year period (2010-2018 inclusive) were identified. Data regarding demographics, radiological parameters and outcomes was recorded. APS was measured on a Launestein radiograph view, with the patient supine, the hip and knee are flexed to 40°, and the hip externally rotated 45°, with film-focus distance of 100 cm. Analysis of the APS was performed to validate a threshold above which AVN occurs.

RESULTS

We identified 147 hips in 142 patients, of which 5 had bilateral slips at the time of presentation. Average anterior physeal separation was 3.8 ± 1.8 mm, with higher grade slips having significantly greater APS values. Increased APS values were seen with Loder "unstable" slips. Seven hips (4.8%) developed AVN, and in these cases the APS was significantly larger than those who did not (8.5 ± 1.4 Vs 3.9 ± 1.7; p < 0.001). Receiver operator curve analysis demonstrated a critical value of 7.5 mm was associated with a 100% sensitivity and 98.6% specificity for AVN. We identified some grade II/moderate slips with high APS values had similar outcomes to grade III/severe slips, and therefore suggest that APS may serve to alert the surgeon on counselling patients on the risk of developing AVN and to consider strategies to minimise the risk of AVN.

CONCLUSIONS

APS is sensitive, specific, accurate and reliable for the association with AVN in SUFE. Its values closely reflect the high AVN rates seen in acute and unstable SUFE. This risk is greatest if the magnitude of APS exceeds the critical value of 7.5 mm.

Intraoperative monitoring of femoral head perfusion in adult femoral neck fractures

Objectives:

To validate a novel intraoperative method of quantifying femoral head perfusion in adult patients with femoral neck fractures and to determine whether the lack of a perfusion waveform correlates with the development of osteonecrosis, nonunion, or reoperation.

Design:

Prospective cohort.

Setting:

Level 1 trauma center.

Patients/Participants:

Nineteen patients with 20 acute femoral neck fractures treated with hip-preserving surgical fixation. All patients underwent intraoperative quantification of femoral head perfusion.

Intervention:

Intraoperative quantification of femoral head perfusion pressure and waveform utilizing an intracranial pressure monitor.

Main outcome measurements:

Radiographic union, avascular necrosis, revision surgery.

Results:

Nineteen patients (8 male, 11 female, average age 56 ± 21 years) with 20 femoral neck fractures were enrolled. Eight fractures were stable (Garden 1-2/OTA B1.1–1.3) and 12 were unstable (Garden 3-4/OTAB2.1–3.3). A waveform was present in 12 of 20 cases. The average pressures were systolic 36.8 mm Hg, diastolic 30.8 mm Hg, pulse pressure 6.0 mm Hg. A perfusion waveform was significantly associated with advanced age (P = 0.02) and accompanied by trend toward stable fracture patterns. There were 4 deaths during the 1-year follow-up period (20%), and there were 5 conversions to total hip arthroplasty (25%). There was no significant association between revision surgery or death with the absence of a waveform.

Conclusions:

Our study demonstrated the feasibility of a relatively low cost, minimally invasive, technique to quantify femoral head perfusion. In our limited sample, the absence of perfusion did not correlate with our main outcomes; however, the trend toward correlation with increased fracture displacement was as expected. A larger cohort of patients will be needed to detect a significant difference between those with and without a perfusion waveform with regards to our primary outcomes. Further study is needed to delineate the role such data may play in medical decision making at the time of index surgery.

Level of Evidence:

Prognostic Level II.