Clinical results at 10 years of minimum follow-up with the ABG 2 hip arthroplasty, matched with ceramic-on-ceramic bearings.

INTRODUCTION: The current study aimed as a primary goal is to assess the results of a ceramic-on-ceramic (CoC) bearing hip system matched with ABG (Anatomic Benoist Girard) 2 components in terms of survivorship. Secondary objectives addressed specifically ceramic-related complications as well as specific patterns at the bone-implant interface. MATERIAL AND METHODS: This is a retrospective bicentric continuous series involving 147 patients (95 males vs. 52 females) who underwent ABG 2 arthroplasties with CoC bearings. One hundred and twenty-five hips were closely followed-up at a mean period of 11.3 years. RESULTS AND DISCUSSION: With a mean follow-up of 11.3 years, nine cases (5.7%) underwent revision surgery, four caused by acetabular aseptic loosening, three by deep infections, one ceramic head fracture, and one femoro-acetabular impingement. The global survivorship was 92.2% at 12.7 years. The Harris Hip Score (HHS) mean scores increased post-operatively from 50.1 up to 96.1 points (p < 0.001). All stems featured patterns of radiological osseous integration onto the hydroxyapatite (HA)-coated zones. No radiological wear or osteolysis of ceramic bearings was demonstrated however, five patients reported hip squeaking using this bearing. This study demonstrated excellent results at mid-term follow-up in patients younger than 70 years of age using cementless ABG 2 components coupled with CoC bearings with no increase in complication rate.

Changes in Femoral Version During Implantation of Anatomic Stems: Implications on Stem Design.

BACKGROUND: Component positioning in total hip arthroplasty (THA) is among the primary indicators for longevity and success. Acetabular component positioning has been discussed in literature at length; however, femoral component positioning is also important as it contributes to combined anteversion. METHODS: In this study, we examined the changes in femoral anteversion after the implantation of anatomic stem ABG II. A cadaveric study, a computed tomography-based computer modeling study, and a clinical study using a navigation system were conducted to document these changes. RESULTS: These studies demonstrated that the anatomic stem ABG II increased the postimplantation femoral version by approximately 7°. The postimplantation versions followed a bimodal distribution. The computed tomography and navigation data also highlighted that the patient population may roughly be divided into 2 groups: the first group that needs anteverted stem and the second group that needs little or no anteversion in the stem to recreate the desired version and offset. CONCLUSION: Based upon our data, we propose a new anatomic stem design that is offered in 2 version angles of 0° and 7° to help create the desired version and offset.

The TESS reverse shoulder arthroplasty without a stem in the treatment of cuff-deficient shoulder conditions: clinical and radiographic results.

BACKGROUND: Reverse total shoulder arthroplasty (RSA) is a recent concept that enables good functional outcomes in cases of massive rotator cuff tear and cuff tear arthropathy. Design parameters influence the functional results and complications. The purpose of this study is to present the results of a novel RSA, the Total Evolutive Shoulder System (TESS; Biomet, Warsaw, IN, USA), based on a reverse corolla without a stem. METHODS: We enrolled 101 patients with 105 RSAs in a prospective study, with a minimum follow-up period of 24 months. The analysis concerned 91 RSAs in 87 patients (61 men and 26 women), with a mean age of 73 years, at a mean follow-up of 41 months (range, 24-69 months). RESULTS: Ninety-six percent of patients rated their satisfaction as good or excellent. Mean flexion was 143° (range, 90°-170°), and mean external rotation was 39° (range, 20°-70°). The Constant score improved from 40 points preoperatively to 68 points at last follow-up (P < .001). The mean American Shoulder and Elbow Surgeons score was 24 points. The mean neck-shaft angle was 154° (range, 142°-165°). Inferior scapular notching occurred in 17 cases (19%). The notching rate was higher when the glenometaphyseal angle increased (P < .001), when the inferior tilt decreased (P = .003), and when the neck-shaft angle increased. There was no evidence of component loosening. CONCLUSION: TESS RSA provided encouraging midterm results with favorable outcomes and a low rate of complications. The stemless TESS with a reverse corolla is a reliable, less invasive system.

A Preliminary In Vivo Assessment of Anterior Cruciate Ligament-Deficient Knee Kinematics With the KneeM Device: A New Method to Assess Rotatory Laxity Using Open MRI.

BACKGROUND: Methods of objectively measuring rotational knee laxity are either experimental or difficult to use in daily practice. A new method has been developed to quantitatively assess rotatory laxity using an open MRI system and new tool, the KneeM device. PURPOSE/HYPOTHESIS: To perform a preliminary evaluation of a novel knee rotation measurement device to assess knee kinematics during flexion in an MRI field, in both anterior cruciate ligament (ACL)-deficient and healthy contralateral knees. The hypothesis was that the KneeM device would allow in vivo reproduction and analysis of knee kinematics during flexion in healthy and ACL-deficient knees. STUDY DESIGN: Controlled laboratory study. METHODS: Ten subjects (7 men and 3 women; mean age ± standard deviation, 32.3 ± 9.4 years) with ACL-deficient knees and contralateral uninjured knees participated in the study. An open MRI was performed with the KneeM device at a mean 4.9 months (range, 3.0-7 months) after ACL injury. The device exerted on the knee an anterior drawer force of 100 N, with an internal rotation of 20°, through the range of flexion (0°, 20°, 40°, and 60°). Both ACL-deficient and healthy contralateral knees were analyzed using the Iwaki method. RESULTS: There was no statistical difference of anterior translation in the medial compartment between intact and ACL-deficient knees at all degrees of flexion. However, significant differences in the anterior translation of the lateral compartment were observed between ACL-deficient and intact contralateral knees at 0° and 20° of flexion (P = .005 and P = .002, respectively). Between 20° and 40°, the lateral plateau of ACL-deficient knees translated 7.7 mm posteriorly, whereas the medial compartment remained stable, reflecting a sudden external rotation of the lateral plateau under the femoral condyle. CONCLUSION: This preliminary study suggests that measurement of tibiofemoral movements in both compartments during flexion using the KneeM device was useful for quantifying rotatory laxity in ACL-deficient knees. Moreover, this device seemed to allow a "mechanized pivot shift" and allowed reproduction of the "pivot" phase in the MRI field between 20° and 40° of flexion. CLINICAL RELEVANCE: This device could be used for diagnostic purposes or to investigate the outcomes of ACL reconstructions.

The cementless anatomic Benoist Girard (ABG) II total hip arthroplasty: a minimum 8-year follow-up study.

We have evaluated 90 consecutive primary cementless ABG II total hip replacements. The bearings combined metal-on-polyethylene in 64 hips, and alumina-on-alumina in 26 hips. At the minimum 8-year follow-up, ten patients had died, seven had been lost to follow-up, two had undergone revision of either or both components, and 68 were still alive and had not been revised. With revision for any reason as the endpoint, the cumulative survival rate at 10years was 97.5%±1.7%, and 98.7%±1.3% for the metal-back cup and the femoral component, respectively. No hip showed peri-acetabular osteolysis. The ABG II total hip arthroplasty has demonstrated favourable clinical and radiological outcomes as well as survival in the current series. Further follow-up is needed to confirm these mid-term results.

A remotely controlled model of spinal cord compression injury in mice: toward real-time analysis.

OBJECT: To date, there has been no efficient therapeutic approach to spinal cord injuries (SCIs). This may be attributable, at least in part, to difficulties in forming predictive and accurate experimental animal models. The authors' previous studies have identified 2 relevant conditions of such a model. The first condition is the ability to compare data derived from rat models of SCI by developing mouse models of SCI that permit access to a large range of transgenic models. The second condition is that the exploration of the consequences of each mechanism of spinal trauma requires modeling the different etiologic aspects of the injury. METHODS: To fulfill these 2 conditions a new model of mouse spinal cord compression injury was devised using a thread-driven olive-shaped compressive device. The authors characterized early motor, sensory, and histological outcomes using 3 olive diameters and different compression durations. RESULTS: A gradual and reproducible functional severity that correlated with lesion extension was demonstrated in 76 mice. To further substantiate the characterization of this model, a noncompetitive N-methyl-d-aspartate antagonist was administered in 30 mice, which demonstrated the involvement of excitotoxicity in this model. CONCLUSIONS: The study demonstrated that spinal olive-compression injury in the mouse is a reproducible, well-characterized, and predictable model for analyzing early events after SCI. The nonmagnetic and remotely controlled design of this model will allow completion of the lesion while the animal is in the MR imaging apparatus, thus permitting further real-time MR imaging studies that will provide insights into the characterization of early events in the spatial and temporal evolution of SCI. Moreover, this model lays the foundation for future in vivo studies of functional and histological outcomes following SCI in genetically engineered animals.