We conducted a prospective randomized study to compare the radiographic and clinical results of dynamic external fixation with those of static external fixation for the treatment of seventy unstable distal radial fractures. Mobilization of the wrist was begun in the dynamic fixator group on the day after surgery. The external fixation frames were kept in place for a mean of six weeks. The patients were assessed clinically and radiographically at the time of removal of the fixator and at three, six, and twelve months.

Dynamic fixation resulted in a significantly better restoration of radial length at all follow-up visits in comparison with static fixation. There were no significant differences in radial tilt or radial inclination between the two groups. Wrist flexion, radial deviation, and pronation-supination were regained significantly faster in the dynamic fixator group. Wrist extension was significantly better in the dynamic fixator group in comparison with the static fixator group at all follow-up times. Self-evaluation with use of the Disabilities of the Arm, Shoulder and Hand score and a visual analog pain score demonstrated no significant differences between the two groups at the time of the latest follow-up. Superficial pin-track infections were significantly more common in the dynamic external fixator group than in the static fixator group.

Continuous dynamic traction with a dynamic external fixator compares favorably with the use of static external fixators for the treatment of unstable fractures of the distal part of the radius.

Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

A variety of surgical techniques have been introduced for the treatment of femoroacetabular impingement, but clinical outcome studies of less-invasive treatment with a minimum duration of follow-up of two years are limited. The purpose of this study was to evaluate the early clinical and radiographic outcomes of combined hip arthroscopy and limited open osteochondroplasty of the femoral head-neck junction for the treatment of cam femoroacetabular impingement.

We performed a retrospective review of our first thirty-five patients (thirty-five hips) in whom cam femoroacetabular impingement had been treated with combined hip arthroscopy and limited open osteochondroplasty. Thirty-five patients (twenty-eight men and seven women) with an average age of thirty-four years and a minimum duration of follow-up of two years were analyzed. The modified Harris hip score was utilized to assess hip function. The Tönnis osteoarthritis grade and the alpha angle were determined to assess osteoarthritis progression and deformity correction, respectively.

The average modified Harris hip score improved from 63.8 points preoperatively to 87.4 points at the time of the last follow-up. Twenty-nine (83%) of the thirty-five patients had at least a 10-point improvement in the Harris hip score, and 71% had a score of >80 points. The average alpha angle was reduced from 58.6° preoperatively to 37.1° at the time of follow-up when measured on cross-table lateral radiographs, from 63.9° to 37.8° when measured on frog-leg lateral radiographs, and from 63.1° to 44.8° when measured on anteroposterior radiographs. Two patients had osteoarthritis progression from Tönnis grade 0 to grade 1. Minor complications included one superficial wound infection, one deep vein thrombosis, and four cases of asymptomatic Brooker grade-I heterotopic ossification. There were no femoral neck fractures or cases of femoral head osteonecrosis, and no hip was converted to an arthroplasty.

Early results indicate that combined hip arthroscopy and limited open osteochondroplasty of the femoral head-neck junction is a safe and effective treatment for femoroacetabular impingement. In our small series, most patients had symptomatic relief, improved hip function, and enhanced activity after two years of follow-up.

Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

The Bernese (Ganz) periacetabular osteotomy is an effective surgical procedure to reorient the acetabulum, allowing restoration of anatomic femoral head coverage and medial translation of the hip in adults with hip dysplasia. However, it is a challenging surgical procedure, and we know of no study that has specifically analyzed the complications and associated factors seen with this procedure in adolescent patients.

A retrospective clinical and radiographic review of a consecutive series of adolescent patients who underwent a Bernese periacetabular osteotomy for hip dysplasia was conducted.

Eighty-three osteotomies were performed in seventy-six patients with an average age (and standard deviation) of 15.6 ± 2.4 years. Significant improvement from the preoperative to the two-year follow-up evaluation was seen radiographically with regard to the lateral center-edge angle (–0.14° to 35.5°), the ventral center-edge angle (–5.13° to 31.3°), and the femoral head extrusion index (38.4% to 7.7%) (p < 0.0001 for all). There were three major complications, including excessive arterial bleeding requiring embolization in a patient with a prior acetabuloplasty, osteonecrosis of the acetabular fragment in a patient with severe dysplasia and subluxation of the hip, and osteonecrosis of the femoral head following combined periacetabular and femoral osteotomies in a patient with Charcot-Marie-Tooth disease. Eighteen hips (22%) had minor complications, including nonunion of the superior pubic ramus osteotomy (five hips), a superficial stitch abscess (four), and transient lateral femoral cutaneous nerve palsy (four). Nine hips (11%) underwent removal of symptomatic screws, and two required a second operation to reposition the acetabular fragment. An underlying diagnosis other than developmental dysplasia increased the prevalence of minor complications (p = 0.0017), while a major complication was more likely with longer surgery time, greater blood loss, and proximal femoral osteotomy.

The Bernese periacetabular osteotomy is a joint-preserving procedure that very effectively corrects acetabular dysplasia in adolescent patients, providing improved radiographic results and a low rate of complications. Although the rate of minor complications is increased when there is an underlying diagnosis other than developmental dysplasia, no other predictors were identified. However, a major complication is more likely with a longer duration of surgery and with a concomitant femoral varus osteotomy.

Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

We previously reported the five-to-six-year results of the use of third-generation alumina-on-alumina bearings in a consecutive series of 100 primary cementless total hip arthroplasties. This report presents the longer-term outcomes of these same bearings, at a minimum of ten years postoperatively. Eighty-six of eighty-eight hips available for the study retained the original bearings at the time of the latest follow-up. Thirteen hips were associated with noise, and six hips demonstrated fretting of the femoral neck on radiographs. Two hips required a change of the bearings because of a ceramic head fracture. The ten-year survival rate of the alumina-on-alumina total hip prostheses, with revision of any implant for any reason as the end point, was 99.0%. On the basis of those results, we concluded that the rate of survival of primary cementless total hip prostheses with third-generation alumina-on-alumina bearings is excellent at ten years. However, the risk of ceramic fracture, noise, and impingement between the metal neck and the ceramic liner should be a concern to surgeons, and patients should be informed of these risks before surgery.

Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Improved metal-on-metal articulations were reintroduced in total hip replacement to avoid the osteolysis sometimes seen with conventional ultra-high molecular weight polyethylene bearings. Osteolysis and local lymphocytic infiltration have been reported at revision of some metal-on-metal devices. We report similar and additional results in a study of second-generation metal-on-metal hip implants retrieved post mortem.

Components and surrounding tissues were collected post mortem from seven patients with nine total hip replacements (Zweymüller SL stem with an Alloclassic cup) with Metasul metal-on-metal articulations. All available patient information was recorded. Radiographs of the hips were evaluated for osteolysis. Sections of joint capsule as well as of the femoral implant with surrounding bone were reviewed, and energy-dispersive x-ray analysis was used to evaluate the composition of wear products. The amount of wear was measured for each component (nine femoral heads and eight cup inserts), when possible, by a coordinate measurement machine with use of the dimensional method.

The patients died between three and ten years after arthroplasty, and six of the seven were asymptomatic at the time of death. One patient, with the highest rate of total wear (i.e., wear of femoral head and acetabular cup; 7.6 µm/yr), had increasing hip pain for one year, and histological analysis confirmed the radiographic findings of osteolysis. For two other patients, histological analysis confirmed the radiographic findings of asymptomatic osteolysis. For three patients, histological analysis revealed osteolysis that had escaped conventional radiographic analysis. Joint capsule tissue showed evidence of metallosis in all hips and local lymphocytic infiltration in eight hips. Energy-dispersive x-ray analysis revealed elements attributable to CoCrMo alloy in all hips and traces of corrosion products in three hips.

The postmortem findings of osteolysis and/or lymphocytic infiltration associated with eight clinically well-functioning, low wear devices (a total wear rate of <4 µm/yr) suggest there may be frequent, unappreciated femoral bone loss and local immunological response in patients with second-generation metal-on-metal hip implants. Compared with previous postmortem studies, our findings showed the extent of osteolysis was similar to that with metal-on-polyethylene articulations.

Statistical independence means that one observation is not affected by another; however, the principle of statistical independence is violated if left and right-side measures within a subject are considered to be independent, because they are usually correlated and can affect each other. The purpose of the present study was to analyze the violation of statistical independence in recent orthopaedic research papers and to demonstrate the effect of statistical analysis that considered the data dependency within a subject.

First, all original articles that had been published in The Journal of Bone and Joint Surgery (American Volume) over a two-year period were evaluated. The analysis was designed to identify articles that included bilateral cases and possible violations of statistical independence. Second, a demonstrative logistic regression without consideration of statistical independence was performed and was compared with a statistical analysis that considered data dependency within a subject. Radiographs of 1200 hips in 600 patients were used to examine the differences in terms of odds ratios (with 95% confidence intervals) of the risk factors for hip osteoarthritis.

Four hundred and eighty-six original articles were reviewed, and 151 articles (including forty-one articles involving the hip, thirty-four involving the knee, twenty-one involving the foot or ankle, nineteen involving the shoulder, ten involving the hand or wrist, nine involving the elbow, and seventeen involving other structures) were considered to include bilateral cases. Of the 486 articles that were reviewed, 120 articles (25%) (including thirty-six articles involving the hip, twenty-six involving the knee, fifteen involving the foot or ankle, fourteen involving the shoulder, seven involving the elbow, six involving the hand or wrist, and sixteen involving other structures) were found to have possibly violated statistical independence. Demonstrative statistical analysis showed that logistic regression was not robust to the violation of statistical independence. The 95% confidence intervals of the odds ratios for the risk factors showed narrower ranges (1.13 to 2.68 times) when data dependency within a subject was not considered.

Researchers need to consider statistical independence when performing statistical analysis, particularly in studies involving bilateral cases. If data dependency within a subject is not considered, studies involving bilateral cases can bias results, depending on the context of those studies.

The localization in tumor tissue of various markers by immunohistochemistry can help to establish a diagnosis or predict prognosis. Nitric oxide is associated with tumors and has been studied indirectly by nitrotyrosine analysis and with use of the enzymes nitric oxide synthase (NOS)1, NOS2, and NOS3. Nitric oxide reacts with superoxide anions to yield peroxynitrite, which has toxic effects on genes. Peroxynitrite adds a nitro group to the benzene ring of tyrosine to form nitrotyrosine. The accumulation of nitrotyrosine, a stable product in cells, indicates the formation of peroxynitrite. Nitric oxide stimulates the production of cyclooxygenase-2 (COX-2), which has been associated with angiogenesis in tumors. Neovascularization influences tumor prognosis, as demonstrated by microvessel studies with use of CD34, an immunohistochemical endothelial cell marker. This study examines the expression of these markers in chondrosarcomas and their relation to histological grade and prognosis.

Tissue microarrays composed of formalin-fixed tissue samples from 101 patients with chondrosarcoma were immunohistochemically stained to localize NOS1, NOS2, NOS3, COX-2, nitrotyrosine, and CD34. Five samples of normal cartilage were used as controls. Patient demographics, selected surgical variables, and tumor grade were tabulated, and the associations were analyzed. Analyses of local and overall survival rates were performed with use of the Kaplan-Meier method, and multivariable analyses were performed.

There was a significant association of nitrotyrosine, COX-2, and CD34 with histological grades (p = 0.022, p = 0.014, and p = 0.028, respectively), but not with overall prognosis (p = 0.064, p = 0.143, and p = 0.581, respectively). The presence of NOS2 was associated with a lower rate of local disease-free survival (p = 0.038), and positive expressions of NOS1 and NOS2 were associated with decreased overall survival rates (p = 0.007 and p < 0.001, respectively). On multivariable analysis, NOS2 expression demonstrated an independent prognostic impact on local disease-free survival; NOS1 and NOS2 expression was a dependent variable, and their isolated or combined expression was related to lower overall survival rates (p = 0.046 and p = 0.004) (hazard ratio, 3.17 [95% confidence interval, 1.0 to 9.8] and 5.58 [95% confidence interval, 1.7 to 18.0], respectively).

Immunohistochemical markers may have an independent value in predicting the prognosis for patients with chondrosarcoma.

Aortic balloon occlusion has been introduced into sacral tumor surgery to reduce extensive hemorrhage. The purposes of this retrospective study were to determine the efficacy of aortic balloon occlusion in decreasing intraoperative and postoperative blood losses and to analyze the complications of this technique.

The cases of 215 patients in whom a sacral tumor had been treated surgically between 1997 and 2009 were studied retrospectively. Ninety-five patients who had had sacral tumor resection without aortic balloon occlusion were compared with 120 patients in whom aortic balloon occlusion had been carried out during the tumor resection. The demographic data, possible factors influencing hemorrhage, and total blood loss volume (including intraoperative and postoperative volumes) were determined with a review of the medical records and compared between the two groups.

There were no significant differences between the two groups in terms of the demographic data, grade of malignancy, tumor blood supply, location of the tumor, percentage of patients who had a recurrent tumor or preoperative radiation, surgical approach, or type of resection. The patients with aortic balloon occlusion had a larger mean tumor volume, more frequently had a sacral reconstruction, and had a longer mean operative time; however, their mean total (2963 mL) and intraoperative (2236 mL) blood loss volumes were lower than those of the patients without occlusion (4337 and 3935 mL, respectively) (p < 0.001). Complications related to aortic balloon occlusion included femoral artery embolism in three patients and hematoma formation at the puncture site in five.

Aortic balloon occlusion decreases the total and intraoperative blood loss volumes in patients treated with sacral tumor surgery who require extensive dissection. There is a low rate of balloon-related complications.

Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Arthrodesis of the first metatarsophalangeal joint is indicated for severe osteoarthritis or as a revision of failed treatment for hallux valgus. The literature suggests that an optimum fused dorsiflexion angle is between 20° and 25° from the axis of the first metatarsal. The purpose of this study was to investigate the relationship between dorsiflexion angle and plantar pressure in the postoperative gait. We assumed that there is a fused dorsiflexion angle at which pressures are minimized under the hallux and the first metatarsal head.

Six cadaver foot specimens underwent incremental changes in simulated fused metatarsophalangeal joint dorsiflexion angle followed by dynamic gait simulation. A robotic gait simulator performed at 50% of body weight and one-fifteenth of physiologic velocity. In vitro tibial kinematics and tendon forces were based on normative in vivo gait and electromyographic data and were manually tuned to match the in vitro ground reaction force and tendon force behavior. Regression lines were calculated for peak pressure and pressure-time integral under the hallux and the metatarsal head by dorsiflexion angle.

Peak pressure and pressure-time integral under the hallux were negatively correlated with dorsiflexion angle (p < 0.004), while peak pressure and pressure-time integral under the metatarsal head were positively correlated with dorsiflexion angle (p < 0.004). The intersection of the regression lines that represented the angle at which peak pressure and pressure-time integral were minimized was 24.7° for peak pressure and 21.3° for pressure-time integral.

Our findings support the hypothesis that an angle-pressure relationship exists following arthrodesis of the first metatarsophalangeal joint and that it is inversely related for the hallux and the metatarsal head. Our results encompass the suggested range of 20° to 25°.

This investigation provides a basis for assessing clinical decisions surrounding operative technique and hardware utilization that may improve gait, quality of life, and functional performance in patients undergoing operative treatment of osteoarthritis of the first metatarsophalangeal joint.

Retrieval studies have demonstrated polyethylene wear and deformation of the anterior aspect of the tibial post of posterior-stabilized total knee replacements. We are not aware of any study that has analyzed the effects of the design of the femoral notch and the anterior aspect of the tibial post of posterior-stabilized total knee replacements on contact area, stress, and location. The purpose of the present study was to determine the levels of contact stress generated in three posterior-stabilized total knee replacement designs when the femoral intercondylar notch impinges on the anterior aspect of the tibial post.

The contact area, mean and peak contact stresses, and contact location at the anterior aspect of the tibial post were determined when a posterior force of 100 N was applied to a NexGen LPS Flex, Genesis II, and Scorpio NRG total knee replacement. Measurements were performed at –15°, –10°, –5°, 0°, and 5° of flexion of the femoral component both in neutral and with 5° of rotation of the tibial component. Each measurement was sequentially performed five times, and the data were compared within and between the designs with use of analysis of variance and a post-hoc Scheffé F test.

The NexGen LPS Flex exhibited two contact areas on the medial and lateral corners of the anterior aspect of the post, whereas both the Genesis II and Scorpio NRG exhibited a single horizontal band. The NexGen LPS Flex showed the largest total contact area of the three designs at –15°, –10°, and 5° of flexion. The NexGen LPS showed the lowest mean contact stress at –15° and 5° but showed the highest peak contact stress at –5° and 0°. The Scorpio NRG showed the highest mean contact stress under all conditions and showed the highest peak contact stress at –15°, –10°, and 5°. With 5° of rotation of the tibial component, peak contact stress increased, relative to neutral, 1.2 to twofold (depending on the flexion angle) in the Genesis II design.

The mean and peak contact stresses were variable for all three designs and the test conditions, approaching and in some cases exceeding the compressive yield stress for polyethylene. The geometry of the metal femoral notch and polyethylene tibial post in the axial and sagittal planes significantly affected contact area, mean and peak stresses, and contact location at the anterior aspect of the tibial post.

This study helps the surgeon to be more aware that high contact stresses under some conditions could lead to deformation and damage of the anterior aspect of the post in these three common designs of cruciate-sparing total knee replacements.