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 left 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 mm. In the medial tangential view, we detected 66.7% at 2 mm penetration of the medial condyle and 100% at 4 mm and 6 mm. 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.

Relationship between developmental canal stenosis and surgical results of anterior decompression and fusion in patients with cervical spondylotic myelopathy.

BACKGROUND: Anterior cervical decompression and fusion (ACDF) has long been the preferred treatment for cervical spondylotic myelopathy (CSM). However, few studies have focused on surgical results of CSM in patients with developmental canal stenosis (DCS). The purpose of this study was to investigate DCS as a comorbidity in patients with CSM and the correlation between surgical results and DCS. METHODS: From January 1995 to December 2005, 122 patients treated with ACDF for CSM were enrolled in this retrospective study. Pavlov's ratio was used to evaluate cervical spinal canal size, with a value of < 0.82 at least one level indicating DCS. Patients were divided into two groups: those with DCS preoperatively (DCS group, n = 50 [41.0 %]) and those without DCS (non-DCS group, n = 72). Clinical data and radiological parameters were compared between groups. RESULTS: There were no significant differences in preoperative and 2-year follow-up Japanese Orthopedic Association scores between groups. Both groups achieved satisfactory fusion rates (DCS, 92.0 %; non-DCS, 93.0 %). Adjacent-segment degeneration (ASD) was detected in 66.0 % of patients in the DCS group and in 43.0 % of patients in the non-DCS group (p = 0.01). However, there was no significant difference in the incidence of ASD requiring surgery between groups (p = 0.20). DISCUSSION: DCS is a common comorbidity in patients with CSM. The findings of this study have added knowledge on the correlation between DCS and ASD after anterior fusion surgery. CONCLUSIONS: DCS did not affect neurologic improvement postoperatively at short-term follow-up. Although DCS increased the incidence of ASD after anterior fusion, it did not predict ASD requiring surgery. Therefore, patients with DCS must receive close follow-up.

Percutaneous Repair Technique for Acute Achilles Tendon Rupture with Assistance of Kirschner Wire.

The aim of this study is to introduce a self-designed, minimally invasive technique for repairing an acute Achilles tendon rupture percutaneously. Comparing with the traditional open repair, the new technique provides obvious advantages of minimized operation-related lesions, fewer wound complications as well as a higher healing rate. However, a percutaneous technique without direct vision may be criticized by its insufficient anastomosis of Achilles tendon and may also lead to the lengthening of the Achilles tendon and a reduction in the strength of the gastrocnemius. To address the potential problems, we have improved our technique using a percutaneous Kirschner wire leverage process before suturing, which can effectively recover the length of the Achilles tendon and ensure the broken ends are in tight contact. With this improvement in technique, we have great confidence that it will become the treatment of choice for acute Achilles tendon ruptures.

Femoral stress and strain changes post-hip, -knee and -ipsilateral hip/knee arthroplasties: a finite element analysis.

OBJECTIVE: To identify the optimal ratio of free femur for minimizing the risks of periprosthetic fracture. METHODS: Three dimensional models of the femur with hip and knee stem elongation were constructed. With the distal femoral condylar surface fixed in a three dimensional model, the femoral head loading was performed according to the methods described by Huiskes and van Rietbergen in the models of hip replacement, knee replacement with or without hip stem or knee stem elongation. The maximum principal stress (MPS) and maximum principal elastic strain (MPES) of the femur were recorded and their relationships to the free femur ratio were analyzed using Pearson's correlation analysis. RESULTS: There were no obvious changes in MPS and MPES with hip stem elongation from 100 to 180 mm. In ipsilateral hip and knee replacement, the MPS and MPES had a tendency to decrease with knee and hip stem elongation. The MPS and MPES were mainly located in the anterior medial side of the middle to distal femur post-hip replacement and distalized with stem elongation. When the knee stem had been elongated more than 120 mm, the stress and strain concentrated strongly in the middle of the femoral shaft. There was a positive correlation between MPS and MPES to the free femur ratio (P < 0.01); however, no optimal ratio of free femur that would minimize the risks of periprosthetic fracture was identified. CONCLUSION: Positive correlations were found between implant free femur and stress and strain changes in total knee arthroplasty, total hip arthroplasty and ipsilateral hip and knee replacement.

Closed patella fracture combined with cruciate ligament injury: a case control study.

BACKGROUND: Patellar fracture and cruciate ligament injury are a common consequence of traumatic knee injury. Patellar fracture combined with cruciate ligament injury is rarely reported, although the mechanisms of two things are similar. This study aimed to evaluate the incidence of closed patella fracture combined with cruciate ligament injury. METHODS: From 2012 March 1 to June 30, magnetic resonance images of 60 patients with unilateral closed patellar fracture were studied in our institution. The mean age of the patients at presentation was 40.2 years (range, 13-64 years) and 48 patients were men. First, patients were divided according to the cause of injury. Twenty-eight patients had high-energy trauma from a falling injury or motor vehicle accident, and 32 patients had low-energy trauma resulting from a tumbling injury. Second, according to the fracture pattern, 31 patients had a transverse fracture and 29 patients had a comminuted fracture. RESULTS: We found seven cases of closed patellar fracture combined with cruciate ligament injury among 60 patients, including two cases of a completely ruptured posterior cruciate ligament, two with a partially torn posterior cruciate ligament, and three with a partially torn anterior cruciate ligament. The percentage of this combined injury was 11.6% (7/60). The incidence of a combined injury of the cruciate ligament with a comminuted fracture (6/29, 20.7%) was significantly higher than that with a transverse fracture (1/31, 3.2%, P < 0.05). The most common mechanism of injury in patellar fracture combined with cruciate ligament injury was high-energy trauma from road traffic accidents (94%), whereas in the patellar fracture alone, it was tumbling (62%). The incidence of combined injury with high-energy trauma (6/28, 21.4%) was significantly higher than that with low-energy trauma (1/32, 3.1%, P < 0.05). CONCLUSIONS: These data suggest that high-energy trauma often results in a comminuted patellar fracture, which is often combined with cruciate ligament injury. Traffic accidents are the main risk factor for this combined injury. Understanding the relationship between patellar fracture and cruciate ligament injury for diagnosis and treatment is important.

Biomechanical comparison of gourd-shaped LCP versus LCP for fixation of comminuted tibial shaft fracture.

The purpose of this study was to compare monotonic biomechanical properties of gourd-shaped LCP fixation with LCP fixation of human tibial shaft in gap fracture mode. Twenty paired fresh cadaveric human tibias were randomly divided into 4 groups (5 pairs each): (1) axial loading single cycle to failure testing, (2) torsion single cycle to failure testing, (3) 4-point bending single cycle to failure testing, and (4) dynamic 4-point bending testing. A 7-hole 4.5 mm gourd-shaped LCP was secured on the anteromedial surface of 1 randomly selected bone from each pair, respectively, using 6 locking screws in the 1st, 2nd, 3rd, 5th, 6th and 7th hole with the middle hole unfilled and just located at the mid-diaphysis of the tibia. A 7-hole 4.5 mm LCP was secured on the other bone with the same method. Standard AO/ASIF techniques were used. After fixation finished, a 10 mm gap in the mid-diaphysis of tibia was created, centrally located at the unfilled hole. The axial, torsional, and bending stiffness and failure strengths were calculated from the collected data in static testings and statistically compared using paired Student's t-test. The 4-point bending fatigue lives of the two constructs were calculated from the dynamic testing data and also statistically compared using paired Student's t-test. Failure modes were recorded and visually analyzed. P<0.05 was considered significant. Results showed that the axial, torsional and bending stiffness of gourd-shaped LCP construct was greater (4%, 19%, 12%, respectively, P<0.05) than that of the LCP construct, and the axial, torsional and bending failure strengths of gourd-shaped LCP construct were stronger (10%, 46%, 29%, respectively, P<0.05) than those of the LCP construct. Both constructs failed as a result of plate plastic torsional deformation. After axial loading and 4-point bending testings, LCP failed in term of an obvious deformation of bent apex just at the unfilled plate hole, while the gourd-shaped LCP failed in term of a deformation of bent arc between the 3rd and 5th holes, which indicated a more consistent stress distribution on gourd-shaped LCP. Fatigue life of gourd-shaped LCP construct was significantly greater than LCP construct (153 836±2 228 vs. 132 471±6 460 cycles, P<0.01). All constructs failed as a result of fracture of the plate through the compression hole of the unfilled combination screw hole. The biomechanical testing showed that gourd-shaped LCP can provide greater stiffness and strength, and longer fatigue life than LCP. The gourd-shaped LCP may be more advantageous mechanically and may reduce the plate breakage rate clinically.

Quantitative score system for the surgical decision on adult femoral neck fractures.

Surgical decision making for femoral neck fractures is currently based on factors such as patient age, fracture type, and medical condition, lacking a quantitative standard. The treatment protocol based on such qualitative assessment has poor operability, greatly affected by the surgeon's subjective factors. As a result, a quantitative score system (QSS) focusing on 5 factors--age, fracture type, bone mineral density, activities of daily living, and medical comorbidities--with a total score of 25 is designed to deal with adult femoral neck fractures. The higher the score, the worse the patient's physiological condition. According to our clinical experience, patients with 1 to 11 points should be treated with internal fixation; patients with 12 to 17 points with total hip arthroplasty (THA), and patients with 18 to 22 points with hemiarthroplasty. Patients with 22 to 25 points should be treated with internal fixation due to the high surgical risk of arthroplasty caused by poor physiological condition. Three hundred seventy-five adult femoral neck fractures were treated on the basis of QSS for this 2-year prospective study. Of these, 242 were treated with low-score internal fixation, 60 with THA, 55 with hemiarthroplasty, and 18 with high-score internal fixation. The revision rates 2 years postoperatively in the low-score internal fixation, THA, and hemiarthroplasty groups were 15.3%, 5.0%, and 5.5%, respectively, which were lower than those from a meta-analysis (internal fixation, 35%; THA, 16%). This QSS helps surgical decision making regarding the treatment choice for adult patients with femoral neck fractures, and good results in preliminary clinical practice have been achieved.