Screw penetration of the iliopsoas muscle causing late-onset pain after total hip arthroplasty: A case report

BACKGROUND Postoperative pain following total hip arthroplasty(THA)may occur in a few patients but may pose a significant challenge to surgeons if the etiology is not identified.Herein,we report the case of a patient who developed late-onset pain following THA due to screw penetration of the iliopsoas tendon.CASE SUMMARY We report the case of a 77-year-old man who developed inguinal pain 7 years after THA.While the symptoms resembled that of iliopsoas impingement by the acetabular cup,the pain resolved only when the supplementary acetabular screw protruding through the ilium was decompressed.Decompression was performed using the pararectus approach.The patient was able to ambulate pain-free immediately after surgery.CONCLUSION A protruded screw through the ilium may penetrate the iliopsoas muscle,causing pain following THA.Pain may resolve with the decompression of the protruded screw.

Femoral Condyles Tangential Views： An Effective Method to Detect the Screw Penetration of Femoral Condyles After Retrograde Nailing

Background： Postoperative knee soft tissue irritation is a common complication after retrograde nail fixation of femoral fractures. Distal locking screw prominence is one of the causes for soft tissue irritation. This study aimed to determine whether the use of the femoral condyles tangential views improve the diagnostic accuracy compared with anteroposterior （A-P） view in detecting distal locking screw penetrations during retrograde femoral nailing. Methods： The angle between the sagittal plane and lateral aspect of the condyle and the angle between the sagittal plane and medial aspect of condyle were measured on computed tomography （CT） images. After the angles were measured and recorded, cadaveric femurs were used in a simulated surgical procedure. The retrograde femoral nail was inserted into the femur and placed distal locking screws, which were let1 2, 4, and 6 mm proud of the medial and lateral condyles for each femur. A-P view, lateral condyle tangential view and medial condyle tangential view were obtained. All fluoroscopic images were recorded and sent to three observers blinded to the experimental procedure to determine whether screws penetrated the condyle cortex or not. Results： According to the results of CT scan, the lateral condyle view was 20.88 ＋ 0.98± and the medial condyle view was 40.46 ± 3.14°. In the A-P view, we detected 0% at 2 mm penetration, 16.7% （lateral condyle screw） and 25.0% （medial condyle screw） at 4 mm, and 41.7% （lateral condyle screw） and 58.3% （medial condyle screw） at 6 mm. In the lateral tangential view, we detected 91.7% at 2 mm penetration of the lateral condyle and 100% at 4 mm and 6 ram. In the medial tangential view, we detected 66.7% at 2 mm penetration of the medial condyle and 100% at 4 mm and 6 ram. The femoral condyle tangential views provided significant improvement in detecting screw penetrations at all lengths （2, 4, and 6 mm） compared with the A-P view （P 〈 0.05）. Conclusions： The femoral condyles tangential views increased the accuracy of detecting screw penetrations on the medial and lateral condyles. Routine clinical use of the femoral condyles tangential views has the potential to increase accuracy in detecting distal locking screw penetration during retrograde femoral nailing.