Patterns of stress distribution at the proximal femur after implantation of a modular neck prosthesis. A biomechanical study.

BACKGROUND: Modular total hip arthroplasty incorporating a double taper design is an evolution offering potential advantages compared to single head-neck taper or monolithic designs. Changes in femoral offset, neck length or femoral anteversion are expected to alter the strain distribution. METHODS: We therefore analyzed the strain patterns after usage of all types of necks of a modular neck prosthesis, implanted in composite femurs. FINDINGS: The load distribution presented a repeatable pattern. Anteverted neck combinations resulted in higher stress at the anterior surface, whereas the retroverted ones at the posterior (e.g. at the middle frontal site, stress is 13.63% higher when we shifted from the long neutral neck to the long 15° anteverted neck and at the middle back site 19.73% higher when we shifted from the long neutral to the long 15° retroverted neck). Compressive stress was larger at the calcar region and exacerbated by the use of the varus neck (e.g. at the frontal 1 site stress increased by 44.01% when we used the long 8° varus neck in comparison to the long neutral neck). Anteverted neck combinations resulted in higher strain at the anterior cortex around the tip of the prosthesis. Short necks exhibited lower stress at the femoral shaft and higher at the trans-trochanteric area. INTERPRETATION: Anteverted neck combinations could be more prone to anterior thigh pain. Because of the possible risk of adaptive hypertrophy and early mechanical failure due to increased stress, the surgeon should be cautious when using necks with combined characteristics or short necks.

Bacterial wound contamination during simple and complex spinal procedures. A prospective clinical study.

BACKGROUND CONTEXT: Spinal procedures have a potential of intraoperative contamination. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used to diagnose postoperative infections after spinal surgery. However, it has not been demonstrated if there is an association between surgical site contamination and clinical manifestation of postoperative infection based on inflammatory markers and patients' clinical course. PURPOSE: The purpose of this prospective study was to evaluate the association between surgical site contamination and the development of a postoperative infection in simple and complex surgical procedures. C-reactive protein and ESR levels were observed. The correlation between their values, surgical time, type of surgical procedures, and contaminated surgical sites was investigated. STUDY DESIGN: Prospective clinical study. PATIENT SAMPLE: The study consisted of 40 patients divided into two groups. Group A included 20 patients (mean age, 46.2 years; 12 women and 8 men) who underwent an open discectomy for a lumbar herniated disc. Group B consisted of 20 patients (mean age, 67.9 years; 11 women and 9 men) who underwent a decompression and instrumented fusion for lumbar spinal stenosis. They were followed up for an average of 26.7 months (range, 11-40 months). OUTCOME MEASURES: Samples were obtained for cultures in standard time intervals during surgery. The types of bacteria cultured were evaluated, and CRP and ESR levels were measured. METHODS: Simple lumbar discectomy (Group A, 20 patients) and instrumented lumbar decompression for degenerative lumbar stenosis (Group B, 20 patients) were performed in a prospective consecutive series of patients. All patients were operated by the same surgeon in the same operating room. Surgical site preparation in each patient was done by a standard manner. Samples were obtained for cultures in standard time intervals during surgery. C-reactive protein and ESR levels were measured preoperatively on the 3rd, 7th, and 21st postoperative days, and the clinical course of each patient was recorded. RESULTS: From 40 patients, three patients in Group A and five patients in Group B, a total of eight patients (20%) had positive cultures for bacteria. There was no statistical significance between contamination and duration of surgery in both groups. None of the patients with positive intraoperative cultures developed any clinical signs of superficial or deep postoperative spinal infection, and no additional antibiotic treatment was administered. Three patients with negative cultures developed a postoperative infection. There were no differences in CRP and ESR values between patients with contamination and noncontamination in both groups. C-reactive protein and ESR levels were significantly elevated in complex procedures (Group B) than in simple procedures (Group A). Statistical analysis of CRP and ESR values in both groups and types of bacteria cultured intraoperatively are presented. CONCLUSIONS: The results of this study demonstrate that intraoperative contamination can occur during simple and complex spinal procedures. In the absence of postoperative signs of infection in patients with intraoperative contamination, there is no need of continuing antibiotic treatment. Postoperative kinetics of CRP and ESR showed to be the same in patients with and without intraoperative contamination. Higher levels of inflammatory markers were noted in complex spinal procedures where instrumentation was applied.

Computer-assisted three-dimensional correlation between the femoral neck-shaft angle and the optimal entry point for antegrade nailing.

Optimal entry point for antegrade femoral intramedullary nailing (IMN) remains controversial in the current medical literature. The definition of an ideal entry point for femoral IMN would implicate a tenseless introduction of the implant into the canal with anatomical alignment of the bone fragments. This study was undertaken in order to investigate possible existing relationships between the true 3D geometric parameters of the femur and the location of the optimum entry point. A sample population of 22 cadaveric femurs was used (mean age=51.09+/-14.82 years). Computed-tomography sections every 0.5mm for the entire length of femurs were produced. These sections were subsequently reconstructed to generate solid computer models of the external anatomy and medullary canal of each femur. Solid models of all femurs were subjected to a series of geometrical manipulations and computations using standard computer-aided-design tools. In the sagittal plane, the optimum entry point always lied a few millimeters behind the femoral neck axis (mean=3.5+/-1.5mm). In the coronal plane the optimum entry point lied at a location dependent on the femoral neck-shaft angle. Linear regression on the data showed that the optimal entry point is clearly correlated to the true 3D femoral neck-shaft angle (R(2)=0.7310) and the projected femoral neck-shaft angle (R(2)=0.6289). Anatomical parameters of the proximal femur, such as the varus-valgus angulation, are key factors in the determination of optimal entry point for nailing. The clinical relevance of the results is that in varus hips (neck-shaft angle

Solitary tibial osteolytic lesion.

We report an unusual case of solitary osteolytic tibial metastasis from a primary endometrial cancer in a 62-year-old woman. The primary cancer was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy combined with postoperative external beam radiotherapy, while the tibial metastasis was treated with an above knee amputation. The rarity of the case lies on the fact that metastases distally to the elbow and knee are uncommon and endometrial cancer rarely gives distal bone metastases and particularly solitary to the extremities.

Combined radiotherapy and indomethacin for the prevention of heterotopic ossification after total hip arthroplasty.

BACKGROUND AND PURPOSE: :Heterotopic ossification (HO) is a frequent complication following total hip arthroplasty. The aim of this study was to evaluate the efficacy of combined radiotherapy and indomethacin as compared to indomethacin alone for the prevention of HO after hip arthroplasty. PATIENTS AND METHODS: 96 patients were prospectively enrolled to receive either a single dose of postoperative radiotherapy of 7.0 Gy and indomethacin for the first 15 postoperative days or indomethacin alone for the same period. A historical group of 50 patients that received indomethacin alone served as control. Primary endpoint was the radiographic evidence of HO at 6 months. Secondary endpoints were the evaluation of factors related to HO development, side effects from each treatment, and group differences in the clinical assessment with the Merle d'Aubigné Score. RESULTS: Four patients in the combined-therapy group developed HO compared to 13 patients in the indomethacin group (p < 0.05) and 13 patients in the historical group (p < 0.05). One patient each in the combined group and the historical group developed Brooker III HO (nonsignificant difference). Duration of surgery and congenital hip disease were associated with HO development in the indomethacin groups, while age and congenital hip disease showed such an association in the combined-therapy group. The side effects and mean Merle d'Aubigné Score did not differ significantly between the three groups. CONCLUSION: Combined radiotherapy and indomethacin was more efficacious in preventing HO after total hip arthroplasty compared to indomethacin alone and should be considered for future investigation.

Cortical desmoid and the four clinical scenarios.

We reviewed four patients diagnosed with a cortical desmoid lesion at the distal posterior medial femur. Each case reflects a clinical scenario that can be present. Cortical desmoid is a benign, self-limited entity which occasionally can exhibit aggressive radiologic features. Here, we present the specific imaging features in association with patients history and clinical findings facilitating establishment of correct diagnosis. Exact diagnosis is important in order to avoid unnecessary biopsy and complicated therapeutic strategies.

Brain abscess and generalized seizure caused by halo pin intracranial penetration: case report and review of the literature.

The objective of our study is to report a rare complication of halo pin insertion associated with an epileptic seizure and brain abscess, and to discuss the diagnostic and therapeutic approach to its management. The treatment of unstable cervical spine injuries with a halo vest is an established procedure. Complications of pin penetration such as brain abscess and seizure are rare, and need to be urgently treated. Intracranial abscess and seizure associated with the use of the halo device is an unusual complication, and only a few cases have been reported in the literature. A 21-year-old male had a halo vest placed for the management of an odontoid type II fracture, which he sustained from a motor vehicle accident. Ten weeks after halo ring placement he complained of headaches which relieved by analgesics. After 2 weeks he was admitted at the emergency unit in an unconscious condition after a generalized tonic-clonic seizure. The halo pins were displaced during the seizure and were removed at his admission. No drainage was noted from the pin sites, and a Philadelphia cervical collar was applied. A brain CT and MRI revealed intracranial penetration of both posterior pins and a brain abscess in the right parietal lobe. Computed tomography of the cervical spine revealed stable fusion of the odontoid fracture. Cultures from the pin sites were negative; however, intravenous wide spectrum antibiotic treatment was administered to the patient immediately for 4 weeks followed by oral antibiotics for additional 2 weeks. Anti-epileptic medication was also started at his admission. The patient was discharged from the hospital in 6 weeks without symptoms, continuing anti-epileptic medication. On the follow-up visits he had fully recovered without any neurologic sequelae. In conclusion, complications of halo pin penetration are rare which need immediate intervention. Any neurologic or infectious, local or generalized, symptom need to be investigated urgently with available imaging techniques and treated promptly. Pin over-tightening may cause bone penetration and possible deep cranial infection with serious complications.

Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: a cadaveric study.

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.

Distal femoral shortening in total hip arthroplasty for complex primary hip reconstruction. A new surgical technique.

Successful total hip arthroplasty (THA) in congenital dislocated hips demands anatomical reduction in the normal center of rotation without overstretching the sciatic nerve and without excessive compression or abnormal forces across the joint. Proximal femoral and subtrochanteric shortening osteotomy has been described for THA for the treatment of dislocated hips. However, these osteotomies are demanding, associated with deformation of femoral canal and nonunion, and may increase the femoral stem stress. This study reports excellent results in 24 patients with a new surgical technique that combines THA with a distal femoral shortening in severely deformed hips using customized components.

Custom-design implants for severe distorted proximal anatomy of the femur in young adults followed for 4-8 years.

BACKGROUND: Treatment of hips with abnormal anatomy is challenging, and requires demanding surgical technique. We report the preoperative planning and the functional outcome of 38 patients with severe distorted anatomy who were treated with custom implants. PATIENTS AND METHODS: 38 consecutive patients (48 hips) were selected for customized femoral implants. The diagnosis was arthrosis due to congenital dislocation of the hip (CDH). We used plain radiographs, CT, and CAD-CAM analysis. The mean age was 47 (22-69) years and the mean preoperative D'Aubigne score was 10 (6-12). The mean follow-up time was 6 (4-8) years. RESULTS: All implants had optimal fit and fill. There were 2 revisions due to infection. No patients had thigh pain and no patients had aseptic loosening. There were 5 intraoperative and 6 postoperative complications. The mean postoperative D'Aubigne score was 17 (10-18). INTERPRETATION: Preoperative planning with modern technology and customized implants makes the procedure accurate, easier for the surgeon, and safer for the patient.

Cementless modular centroid reconstruction cup in young adults with congenital dysplasia of the hip.

The anatomic abnormalities associated with the dysplastic acetabulum make total hip arthroplasty a very complex and challenging procedure. Various techniques have been reported for the reconstruction of the dysplastic acetabulum. This prospective study examined the clinical results and technical challenges associated with acetabular reconstruction using a cementless modular centroid reconstruction cup in 62 dysplastic hips. The mean follow-up period was 62 +/- 9.2 months (range, 46-84 months). No patient was lost to follow-up. There were no revisions and no radiographic signs of osteolysis. There was a significant improvement in hip pain (P < .0001), mobility (P < .0001), and walking (P < .0001) according to D'Aubigne score. Midterm results have been favorable and patients have gained high clinical function. Longer-term follow-up is registered concerning wear and loosening.

Intrinsic haemangioma of the median nerve: report of a case and review of the literature.

Intrinsic haemangioma of the median nerve is an extremely rare tumor that represents a challenge to diagnose and treat. Only a few cases have been reported in the literature. We present a 10-year-old girl who was diagnosed having an intrinsic haemangioma of the median nerve and treated with total surgical resection of the tumor, under high magnification, using microneurolysis and without the need to resect and graft the median nerve. Three years later, the patient is free of symptoms and no recurrence of the mass was noticed.

Long-term results of various therapy concepts in severe pilon fractures.

INTRODUCTION: Intra-articular fractures of the tibia plafond are among the most challenging of orthopaedic problems. This is a retrospective case-control study of surgically treated pilon fractures which was undertaken to compare the internal fixation with the two external fixation methods. METHODS: This is a case-control study of 55 patients with 55 pilon fractures. There were 36 type C and 19 type B. Of these fractures, 24 were open and 31 closed. Three surgical protocols were used. In 20 patients, Group A, a half pin external fixator with ankle spanning was performed. The mean age of patients was 42.0 years (22.0-74.0), SD 14.1 and the mean follow-up was 77.7 months (38.0-132.0), SD 25.4. In 22 patients, Group B, a single ankle sparring ring hybrid external fixator under a small arthrotomy was performed. The mean age of patients was 48.4 years (28.0-76.0), SD 12.4 and mean follow-up was 67.9 months (36.0-132.0), SD 27.8. In 13 patients, Group C, a two-staged internal fixation was performed. The mean age was 45.6 years (30.0-66.0), SD 9.7 and the mean follow-up was 78.6 months (55.0-132.0), SD 25.4. We addressed the dissimilarity of the type of fracture in each group performing supplementary stratified analyses within each fracture type group. RESULTS: Group A had union in 6.9 months, group B in 5.6 months and group C in 5.1 months; P = 0.009. Six patients (Group A), two (Group B), and one (Group C) had limitation of ankle motion; P = 0.47. One patient from group C developed infection and the plate was removed. Four patients (Group A), one (Group B), and one (Group C) have developed posttraumatic arthritis (loss of joint space and pain); P = 0.25. Seven patients from Group A have reduced their activities; P = 0.004. In stratified statistical analysis by type of fracture, the associations noted for both fracture groups combined were also noted separately within each fracture group. CONCLUSION: In this long term follow-up study, the two-staged internal fixation and the hybrid fixation with small arthrotomy were equally efficacious in achieving bone union. Patients in external fixation with the ankle spanning had a significantly higher rate of delayed union. Also more patients in this group have reduced their activities.

Prevention of heterotopic ossification in high-risk patients with total hip arthroplasty: the experience of a combined therapeutic protocol.

The combination of radiotherapy and indomethacin for the prevention of heterotopic ossification (HO) in high-risk patients undergoing total hip arthroplasty (THA) has not been reported. The aim of the present study was to present the experience of our department with this combined therapeutic protocol. Fifty-four patients who underwent THA received a single dose of 7 Gy of postoperative radiotherapy and 75 mg of indomethacin for 15 days. Patients were analyzed for clinical and radiographical evidence of HO development at 1 year postoperatively. The overall radiographical incidence of HO was 20.4% (95% CI 10.6-33.5%), while only 1 patient with clinically significant HO was seen. Patients with secondary arthritis due to congenital hip disease had a statistically significantly higher incidence of HO compared with those with osteoarthrosis. The clinical assessment with the Merle d'Aubigné score showed that patients with radiographic documentation of HO had a lower mean score compared with those with no evidence of HO. No treatment-related side effects were seen. Combined radiotherapy and indomethacin was effective in preventing heterotopic ossification after total hip arthroplasty. The evaluation of this efficacy compared with radiotherapy or NSAIDs alone should be the future target of larger randomized designs.