How Do Classic (Static) RSA and Patient Motion Artifacts Affect the Assessment of Migration of a TKA Tibial Component? An In Vitro Study.

BACKGROUND: Classic (static) Roentgen stereophotogrammetric analysis (RSA) is the current gold standard to assess, in vivo, the migration of total joint arthroplasty components. To prevent potential patient motion artifacts during the acquisition of paired radiostereometric images, images must be taken by simultaneously firing both X-ray tubes. However, the influence of nonsynchronized RSA paired images or patient motion artifacts on the precision of RSA and the assessment of implant migration is not well understood. QUESTIONS/PURPOSES: We assessed (1) the effect of possible patient motion on the precision of RSA and (2) apparent differences in implant migration among axes (in-plane and out-of-plane translations and in-plane and out-of-plane rotations) of possible motion artifacts. METHODS: Radiographs of two tibial knee arthroplasty components, each fixed in two bone-implant models as a customized phantom, were taken in a uniplanar measurement setup. We evaluated both model-based (implant models from reversed engineering) and marker-based (additional attached implant markers) RSA approaches. Between the simulated reference and follow-up examinations, we used one of the bone-implant models to simulate patient motion and the other to simulate no patient motion in parallel. Two defined protocols were followed for each of the bone-implant models: no-motion and simulated motion protocols. RSA image pairs were analyzed using a model-based RSA software package (MBRSA 4.1, RSA core ). Precision was calculated through repeat examinations, and migration of the two components was assessed for comparison of the components with each other. Measurements were taken along the medial-lateral and posterior-anterior axes for translations and around the cranial-caudal axis for rotations. The maximum total point motion was measured for comparison between the two components. RESULTS: The effect of simulated patient motion was generally small, except in the cranial-caudal axis, but the induced imprecision associated with motion was larger in model-based RSA than it was in marker-based RSA. The mean ± standard deviation values of precision in model-based RSA were 0.035 ± 0.015 mm, 0.045 ± 0.014 mm, and 0.049 ± 0.036 mm greater than those in marker-based RSA, in accordance with the simulated motion protocol in translations along the medial-lateral axis (0.018 ± 0.004 mm; p = 0.01), along the posterior-anterior axis (0.018 ± 0.007 mm; p = 0.003), and rotations around the cranial-caudal axis (0.017 ± 0.006 mm; p = 0.02). Apparent differences in implant migration were the greatest for the maximum total point motion. The maximum total point motion increased from 0.038 ± 0.007 mm for the no-motion protocol to 1.684 ± 0.038 mm (p < 0.001) for the simulated motion protocol in marker-based RSA, and from 0.101 ± 0.027 mm for the no-motion protocol to 1.973 ± 0.442 mm (p < 0.001) for the simulated motion protocol in model-based RSA, and was the worst-case scenario regarding patient motion artifacts. CONCLUSION: Patient motion exceeding 1 mm or 1° on nonsynchronized RSA images affects measurement errors regarding the detection of migration of a tibial component. In clinical RSA studies, the effect of patient motion on the assessment of implant migration should be of particular concern, even if clinical RSA systems have acceptable precision. Specially trained radiographers are crucial for correctly acquiring radiographs, especially when simultaneous radiography exposures are not electronically automated. In general, RSA requires synchronized image acquisition, and this should be the state-of-the-art. CLINICAL RELEVANCE: In clinical RSA studies, precision assessed by repeat examinations may not be reliable using the current standards that are widely used in radiology departments. When assessing implant migration for reliability, comparison of the maximum total point motion between the tested (simulated motion) implant and baseline (no-motion) implant, as in this study, is advocated because of the accurate detection of patient motion artifacts.

Effects of exercise and cold-water exposure on microvascular muscle perfusion.

PURPOSE: Microvascular blood flow (MBF) and its intramuscular regulation are of importance for physiological responsiveness and adaptation. The quantifiable in-vivo monitoring of MBF after cycling or systemic cold-water exposure may reveal new insights into capillary regulatory mechanisms. This study aimed to assess the role of exercise and cold therapy on MBF by using contrast-enhanced ultrasound (CEUS). METHODS: Twenty healthy athletes were recruited and randomly assigned to an intervention (IG) or a control group (CG). MBF was quantified in superficial (rectus femoris, RF) and deep muscle layers (vastus intermedius, VI). Representative perfusion parameters (peak enhancement (PE) and wash-in area under the curve (WiAUC)) were measured after a standardized measurement protocol for both groups at resting conditions (t0) and after cycling (20 min., 70% Watt max, t1) for both groups, after cold-water immersion exposure for IG (15 min., 12°C) or after precisely 15 minutes of rest for CG (t2) and for both groups after 60 minutes of follow-up (t3). RESULTS: At t1, MBF in VI increased significantly compared to resting conditions in both groups in VI (p= 0.02). After the cold-water exposure (t2), there were no statistically significant changes in perfusion parameters as well as after 60 minutes of follow-up (t3) (p = 0.14). CONCLUSION: Cycling leads to an upregulation of MBF. However, cold exposure does not change the MBF. The implementation of CEUS during different physiological demands may provide deeper insight into intramuscular perfusion regulation and regenerative processes.

Preoperative planning of total knee arthroplasty: reliability of axial alignment using a three-dimensional planning approach.

BACKGROUND: Preoperative templating of total knee arthroplasty (TKA) can nowadays be performed three-dimensionally with software solutions using computed tomography (CT) datasets. Currently there is no consensus concerning the axial orientation of TKA components in three-dimensional (3D) planning. PURPOSE: To assess intra-/inter-observer reliability of detection of different bony landmarks in planning axial component alignment using axial CT images and 3D reconstructions. MATERIAL AND METHODS: Intra- and inter-observer reliability of determination of four predefined axial femoral and tibial axes was calculated using data from CT scans. Axes determination was performed on the axial slices and on the 3D reconstruction using preoperative planning software. In summary, 61 datasets were analyzed by one medical student (intra-observer reliability) and 15 datasets were analyzed by four different observers independently (inter-observer reliability). RESULTS: For the femur, clinical epicondylar axis and posterior condylar axis showed the best reliability with an inter-observer variability of 0.7° and 0.5°, respectively. For the tibia, posterior condylar axis provided best reliability (inter-observer variability: 1.7°). Overall variability was greater for tibial than for femoral axes. Reliability of axis determination was more accurate using axial CT slices rather than 3D reconstructions. CONCLUSION: The femoral clinical epicondylar axis is highly reliable. Landmarks for the tibia are not as easily identifiable as for the femur. The tibial posterior condylar axis presents the axis with highest reliability. Based on these results, clinical epicondylar axis for orientation of the femoral TKA component and posterior condylar axis for the tibial implant, both defined on axial slices can be recommended.

Effect of compression garments on muscle perfusion in delayed-onset muscle soreness: A quantitative analysis using intravoxel incoherent motion MR perfusion imaging.

The aim of this prospective cohort study was to evaluate the effect of compression garments under resting conditions and after the induction of delayed-onset muscle soreness (DOMS) by MR perfusion imaging using intravoxel incoherent motion (IVIM). Magnetic resonance imaging of both lower legs of 16 volunteers was performed before and after standardized eccentric exercises that induced DOMS. A compression garment (21-22 mmHg) was worn during and for 6 h after exercise on one randomly selected leg. IVIM MR imaging, represented as total muscle perfusion D*f, perfusion fraction f and tissue diffusivity D, were compared between baseline and directly, 30 min, 6 h and 48 h after exhausting exercise with and without compression. Creatine kinase levels and T2-weighted images were acquired at baseline and after 48 h. DOMS was induced in the medial head of the gastrocnemius muscle (MGM) in all volunteers. Compression garments did not show any significant effect on IVIM perfusion parameters at any time point in the MGM or the tibialis anterior muscle (p > 0.05). Microvascular perfusion in the MGM increased significantly in both the compressed and noncompressed leg between baseline measurements and those taken directly after and 30 min after the exercise: the relative median f increased by 31.5% and 24.7% in the compressed and noncompressed leg, respectively, directly after the exercise compared with the baseline value. No significant change in tissue perfusion occurred 48 h after the induction of DOMS compared with baseline. It was concluded that compression garments (21-22 mmHg) do not alter microvascular muscle perfusion at rest, nor do they have any significant effect during the regeneration phase of DOMS. In DOMS, only a short-term effect of increased muscle perfusion (30 min after exercise) was observed, with normalization occurring during regeneration after 6-48 h. The normalization of perfusion independently of compression after 6 h may have implications for diagnostic and therapeutic strategies and for the better understanding of pathophysiological pathways in DOMS.

Different Effects of Foam Rolling on Passive Tissue Stiffness in Experienced and Nonexperienced Athletes.

CONTEXT: Foam rolling (FR) has been developed into a popular intervention and has been established in various sports disciplines. However, its effects on target tissue, including changes in stiffness properties, are still poorly understood. OBJECTIVE: To investigate muscle-specific and connective tissue-specific responses after FR in recreational athletes with different FR experience. DESIGN: Case series. SETTING: Laboratory environment. PARTICIPANTS: The study was conducted with 40 participants, consisting of 20 experienced (EA) and 20 nonexperienced athletes (NEA). INTERVENTION: The FR intervention included 5 trials per 45 seconds of FR of the lateral thigh in the sagittal plane with 20 seconds of rest between each trial. MAIN OUTCOME MEASURES: Acoustic radiation force impulse elastosonography values, represented as shear wave velocity, were obtained under resting conditions (t0) and several times after FR exercise (0 min [t1], 30 min [t2], 6 h [t3], and 24 h [t4]). Data were assessed in superficial and deep muscle (vastus lateralis muscle; vastus intermedius muscle) and in connective tissue (iliotibial band). RESULTS: In EA, tissue stiffness of the iliotibial band revealed a significant decrease of 13.2% at t1 (P ≤ .01) and 12.1% at t3 (P = .02). In NEA, a 6.2% increase of stiffness was found at t1, which was not significantly different to baseline (P = .16). For both groups, no significant iliotibial band stiffness changes were found at further time points. Also, regarding muscle stiffness, no significant changes were detected at any time for EA and NEA (P > .05). CONCLUSIONS: This study demonstrates a significant short-term decrease of connective tissue stiffness in EA, which may have an impact on the biomechanical output of the connective tissue. Thus, FR effects on tissue stiffness depend on the athletes' experience in FR, and existing studies have to be interpreted cautiously in the context of the enrolled participants.

Long-term Results of Conservative Therapy of Adolescent Idiopathic Scoliosis Using the Cheneau Brace.

Adolescent idiopathic scoliosis is a disease of the growing skeleton. The goal in therapy is to decelerate or to prevent progression of the spinal curve. As part of a retrospective study the patient group of the scoliosis surgery from 1995-2016 was analysed according to the inclusion criteria of the Scoliosis research Society (SRS). 159 of 643 of the patients fullfilled the specific criteria. The assessment of effectiveness was based on the progression of the angle of curvature. If it was ≤5° it was judged positively. The therapy in accordance to Cheneau is a full-time bracing orthosis. Data from 159 patients - 136 fem. (85.5%), 23 male (14.5%) was analysed. The average age at the beginning of treatment was 13.3±1.7 years. The average duration was 3.47±1.2 years. The average Cobb-angle before treatment was 28.39°±9.44°. At the completion is was 27.7°±12.34°. Stabilisation of scoliosis (≤5°) was achieved for 136 of the patients (85.5%). The final follow-up showed a progression of the Cobb angel>5° in 23 cases, of which 19 had to undergo secondary surgery. The length of therapy had a positive influence (p=0.057) on the result. Brace treatment constitutes an effective method of therapy at curvatures between 20-40°. Short duration of therapy correlates with a expressively increased risk towards progression (p=0.057). The Cheneau brace treatment constitutes an effective treatment at curvature angles between 20-40°. The risk of progression can be reduced by a timely and correct identification.

Model-based roentgen stereophotogrammetric analysis using elementary geometrical shape models: 10 years results of an uncemented acetabular cup component.

BACKGROUND: Non-cemented acetabular cup components demonstrated different clinical performance depending on their surface texture or bearing couple. However, clinical osseointegration needs to be proved for each total joint arthroplasty (TJA) design. Aim of this study was to detect the in vivo migration pattern of a non-cemented cup design, using model-based roentgen stereophotogrammetric analysis with elementary geometrical shape models (EGS-RSA) to calculate early cup migration. METHODS: Interchangeable applicability of the model-based EGS-RSA method next to gold standard marker-based RSA method was assessed by clinical radiographs. Afterwards, in vivo acetabular cup migration for 39 patients in a maximum follow up of 120 months (10 years) was calculated using model-based EGS-RSA. RESULTS: For the axes with the best predictive capability for acetabular cup loosening, mean (±SD) values were calculated for migration and rotation of the cup. The cup migrated 0.16 (±0.22) mm along the cranio-caudal axis after 24 months and 0.36 (±0.72) mm after 120 months, respectively. It rotated - 0.61 (±0.57) deg. about the medio-lateral axis after 24 months and - 0.53 (±0.67) deg. after 120 months, respectively. CONCLUSIONS: Interchangeable applicability of model-based EGS-RSA next to gold standard marker-based RSA method could be shown. Model-based EGS-RSA enables an in vivo migration measurement without the necessity of TJA specific surface models. Migration of the investigated acetabular cup component indicates significant migration values along all the three axes. However, migration values after the second postoperative year were within the thresholds reported in literature, indicating no risk for later aseptic component loosening of this TJA design.

Perioperative complications of scoliosis surgery in patients with Duchenne muscular dystrophy and spinal muscular atrophy, focussing on wound healing disorders.

PURPOSE: Patients with Duchenne muscular dystrophy (DMD) or spinal muscular atrophy (SMA), both neuromuscular diseases, sustain spinal scoliosis in the course of their disease. To reduce the concomitant major morbidity and to improve their quality of life, patients require surgical spine stabilization. This can lead to complications like respiratory, cardiac or neurological complications or wound healing disorders (WHD). To find out the different complexities and risk factors increasing the chance to develop a WHD, the inpatient database was analyzed. METHODS: We performed a retrospective statistical study. Therefore, we analyzed the inpatient database of 180 patients (142 DMD and 38 SMA patients). The focus was on WHD. To figure out the risk factors leading to WHD, we conducted a logistic regression. RESULTS: Cardiac complications occurred most frequently, followed by pulmonary complications and neurological lesions. Fifty-seven out of 180 patients developed a WHD. In 23 cases the WHD was aseptic, in the other 34 cases dermal organisms, Pseudomonas species and intestinal organisms were responsible. By means of the logistic regression, we were able to identify two more risk factors, in addition to diagnosis and gender, for developing a WHD in our patients: the year of surgery and the direction of pelvic tilt. CONCLUSIONS: Most common complications following scoliosis surgery are respiratory and cardiac complications. WHD is a severe complication that implies a prolonged therapy. Some risk factors for developing WHD could be identified in this analysis. Specifically, these were the date of surgery and the direction of pelvic tilt.

Antibacterial Effect of a 4x Cu-TiO2 Coating Simulating Acute Periprosthetic Infection-An Animal Model.

The purpose of our study was to investigate the antibacterial effect of a spacer (Ti6Al4V) coated with 4x Cu-TiO2 in an animal model simulating an acute periprosthetic infection by Staphylococcus aureus. Ti6Al4 bolts contaminated with Staphylococcus aureus were implanted into the femoral condyle of rabbits (n = 36) divided into 3 groups. After one week in group 1 (control) the bolts were removed without any replacement. In group2 Ti6Al4V bolts with a 4x Cu-TiO2 coating and in group 3 beads of a gentamicin-PMMA chain were imbedded into the borehole. Microbiological investigation was performed at the primary surgery, at the revision surgery and after scarification of the rabbits 3 weeks after the first surgery. Blood tests were conducted weekly. The initial overall infection rate was 88.9%. In group 2 and 3 a significant decrease of the infection rate was shown in contrast to the control group. The C-reactive protein (CRP) levels declined one week after the first surgery except in the control group where the CRP level even increased. This is the first in vivo study that demonstrated the antibacterial effects of a fourfold Cu-TiO2 coating. For the future, the coating investigated could be a promising option in the treatment of implant-associated infections.

Negative pressure wound therapy for seroma prevention and surgical incision treatment in spinal fracture care.

To evaluate the clinical use and economic aspects of negative pressure wound therapy (NPWT) after dorsal stabilisation of spinal fractures. This study is a prospective randomised evaluation of NPWT in patients with large surgical wounds after surgical stabilisation of spinal fractures by internal fixation. Patients were randomised to either standard wound dressing treatment (group A) or NPWT (group B). The wound area was examined by ultrasound to measure seroma volumes in both groups on the 5th and 10th day after surgery. Furthermore, data on economic aspects such as nursing time for wound care and material used for wound dressing were evaluated. A total of 20 patients (10 in each group) were enrolled. Throughout the whole study, mean seroma volume was significantly higher in group A than that in group B (day 5: 1·9 ml versus 0 ml; P = 0·0007; day 10: 1·6 ml versus 0·5 ml; P <0·024). Furthermore, patients of group A required more wound care time (group A: 31 ± 10 minutes; group B 13·8 ± 6 minutes; P = 0·0005) and more number of compresses (total number; group A 35 ± 15; group B 11 ± 3; P = 0·0376). NPWT reduced the development of postoperative seroma, reduced nursing time and reduced material required for wound care.

Release of Cu2+ from a copper-filled TiO2 coating in a rabbit model for total knee arthroplasty.

The aim of this study was the investigation of a copper-filled TiO2 coating, that in vitro showed good antibacterial properties combined with good tissue tolerance in an animal model. To better understand the antibacterial mechanism of the bioactive coating the release of copper (Cu) ions over time was monitored to be able to detect possible threats as well as possible fields of application. 30 New Zealand White rabbits were divided into two groups with 15 animals per group. In group 1 (control group) Ti6Al4 V bolts were implanted into the distal femur, in group 2 the Ti6Al4 V bolts were coated with four TiO2-coatings with integrated Cu(2+)-ions (4 × Cu-TiO2). Blood tests were performed weekly until the animals were sacrificed 4 weeks postoperative. The maximum peak of Cu and ceruloplasmin concentration could be seen in both groups one week postoperative, whereas the Cu values in group II were significantly higher. The Cu concentration in both groups approximated the initial basic values 4 weeks postoperative. The 4 × Cu-TiO2 coating tested in our rabbit model for total knee arthroplasty is an active coating that releases potentially antibacterial Cu(2+) for 4 weeks with a peak 1 week postoperative. The bioactive coating could be a promising approach for a use in the field of implant related infection, orthopaedic revision and tumor surgery in the future.

Orthopedic management of patients with Pompe disease: a retrospective case series of 8 patients.

INTRODUCTION: Pompe disease (PD), a lysosomal storage disease as well as a neuromuscular disorder, is a rare disease marked by progressive muscle weakness. Enzyme replacement therapy (ERT) in recent years allowed longer survival but brought new problems to the treatment of PD with increasing affection of the musculoskeletal system, particularly with a significantly higher prevalence of scoliosis. The present paper deals with the orthopedic problems in patients with PD and is the first to describe surgical treatment of scoliosis in PD patients. PATIENTS AND METHODS: The orthopedic problems and treatment of eight patients with PD from orthopedic consultation for neuromuscular disorders are retrospectively presented. We analyzed the problems of scoliosis, hip dysplasia, feet deformities, and contractures and presented the orthopedic treatment options. RESULTS: Six of our eight PD patients had scoliosis and two young patients were treated by operative spine stabilization with benefits for posture and sitting ability. Hip joint surgery, operative contracture release, and feet deformity correction were performed with benefits for independent activity. CONCLUSION: Orthopedic management gains importance due to extended survival and musculoskeletal involvement under ERT. Surgical treatment is indicated in distinct cases. Further investigation is required to evidence the effect of surgical spine stabilization in PD.

Uncemented femoral revision arthroplasty using a modular tapered, fluted titanium stem: 5- to 16-year results of 163 cases.

BACKGROUND AND PURPOSE: Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series. PATIENTS AND METHODS: We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5-16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined. RESULTS: Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p<0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB-III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95-100). INTERPRETATION: This is one of the largest medium- to long-term analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years.

Orthopaedic Disorders in Myotonic Dystrophy Type 1: descriptive clinical study of 21 patients.

BACKGROUND: Myotonic Dystrophy Type 1 (DM1) is the most common form of hereditary myopathy presenting in adults. This autosomal-dominant systemic disorder is caused by a CTG repeat, demonstrating various symptoms. A mild, classic and congenital form can be distinguished. Often the quality of life is reduced by orthopaedic problems, such as muscle weakness, contractures, foot or spinal deformities, which limit patients' mobility.The aim of our study was to gather information about the orthopaedic impairments in patients with DM1 in order to improve the medical care of patients, affected by this rare disease. METHODS: A retrospective clinical study was carried out including 21 patients (11 male and 10 female), all diagnosed with DM1 by genetic testing. All patients were seen during our special consultations for neuromuscular diseases, during which patients were interviewed and examined. We also reviewed surgery reports of our hospitalized patients. RESULTS: We observed several orthopaedic impairments: spinal deformities (scoliosis, hyperkyphosis, rigid spine), contractures (of the upper extremities and the lower extremities), foot deformities (equinus deformity, club foot, pes cavus, pes planovalgus, pes cavovarus, claw toes) and fractures.Five patients were affected by pulmonary diseases (obstructive airway diseases, restrictive lung dysfunctions). Twelve patients were affected by cardiac disorders (congenital heart defects, valvular heart defects, conduction disturbances, pulmonary hypertension, cardiomyopathy).Our patients received conservative therapy (physiotherapy, logopaedic therapy, ergotherapy) and we prescribed orthopaedic technical devices (orthopaedic custom-made shoes, insoles, lower and upper leg orthoses, wheelchair, Rehab Buggy). We performed surgery for spinal and foot deformities: the scoliosis of one patient was stabilized and seven patients underwent surgery for correction of foot deformities. CONCLUSIONS: An orthopaedic involvement in DM1 patients should not be underestimated. The most common orthopaedic impairments are contractures, foot deformities and spinal deformities. Contractures are typically located distally in the lower extremities, but can also occur in the hip or shoulder joints. Foot deformities could be treated with orthopaedic custom-made shoes, orthoses or insoles. Surgery is indicated for severe foot deformities or contractures.

Natural course of scoliosis in proximal spinal muscular atrophy type II and IIIa: descriptive clinical study with retrospective data collection of 126 patients.

BACKGROUND: Progressive scoliosis, pelvic obliquity and increasing reduction of pulmonary function are among the most significant problems for patients with SMA type II and SMA type III once they have lost the ability to walk. The aim of this study was to examine and document the development and natural course of scoliosis in patients with spinal muscular atrophy type II and IIIa. METHODS: For the purposes of a descriptive clinical study, we observed 126 patients, 99 with SMA II and 27 with SMA IIIa and the data of scoliosis, pelvic obliquity and relative age-dependent inspiratory vital capacity were evaluated. RESULTS: Scoliosis and pelvic obliquity were regularly observed already in children under 4 years old in the group with SMA II. The severity and progression of both conditions were much more pronounced in the SMA II group than in the IIIa group. There was already a distinct reduction in relative vital capacity in the group of 4- to 6-year-olds with SMA II. CONCLUSIONS: The differences between the two SMA types II and IIIa described in this study should be taken into consideration when developing new treatments and in management of scoliosis in the childhood years of these patients.

Impaction grafting in the femur in cementless modular revision total hip arthroplasty: a descriptive outcome analysis of 243 cases with the MRP-TITAN revision implant.

BACKGROUND: We present a descriptive and retrospective analysis of revision total hip arthroplasties (THA) using the MRP-TITAN stem (Peter Brehm, Weisendorf, GER) with distal diaphyseal fixation and metaphyseal defect augmentation. Our hypothesis was that the metaphyseal defect augmentation (Impaction Bone Grafting) improves the stem survival. METHODS: We retrospectively analyzed the aggregated and anonymized data of 243 femoral stem revisions. 68 patients with 70 implants (28.8%) received an allograft augmentation for metaphyseal defects; 165 patients with 173 implants (71.2%) did not, and served as controls. The mean follow-up was 4.4 ± 1.8 years (range, 2.1-9.6 years). There were no significant differences (p > 0.05) between the study and control group regarding age, body mass index (BMI), femoral defects (types I-III as described by Paprosky), and preoperative Harris Hip Score (HHS). Postoperative clinical function was evaluated using the HHS. Postoperative radiologic examination evaluated implant stability, axial implant migration, signs of implant loosening, periprosthetic radiolucencies, as well as bone regeneration and resorption. RESULTS: There were comparable rates of intraoperative and postoperative complications in the study and control groups (p > 0.05). Clinical function, expressed as the increase in the postoperative HHS over the preoperative score, showed significantly greater improvement in the group with Impaction Bone Grafting (35.6 ± 14.3 vs. 30.8 ± 15.8; p ≤ 0.05). The study group showed better outcome especially for larger defects (types II C and III as described by Paprosky) and stem diameters ≥ 17 mm. The two groups did not show significant differences in the rate of aseptic loosening (1.4% vs. 2.9%) and the rate of revisions (8.6% vs. 11%). The Kaplan-Meier survival for the MRP-TITAN stem in both groups together was 93.8% after 8.8 years. [Study group 95.7% after 8.54 years ; control group 93.1% after 8.7 years]. Radiologic evaluation showed no significant change in axial implant migration (4.3% vs. 9.3%; p = 0.19) but a significant reduction in proximal stress shielding (5.7% vs. 17.9%; p < 0.05) in the study group. Periprosthetic radiolucencies were detected in 5.7% of the study group and in 9.8% of the control group (p = 0.30). Radiolucencies in the proximal zones 1 and 7 according to Gruen occurred significantly more often in the control group without allograft augmentation (p ≤ 0.05). CONCLUSION: We present the largest analysis of the impaction grafting technique in combination with cementless distal diaphyseal stem fixation published so far. Our data provides initial evidence of improved bone regeneration after graft augmentation of metaphyseal bone defects. The data suggests that proximal metaphyseal graft augmentation is beneficial for large metaphyseal bone defects (Paprosky types IIC and III) and stem diameters of 17 mm and above. Due to the limitations of a retrospective and descriptive study the level of evidence remains low and prospective trials should be conducted.

Long-Term Clinical and Radiologic Outcome Following Surgical Treatment of Lumbar Spondylodiscitis: A Retrospective Bicenter Study.

BACKGROUND AND STUDY AIMS: Spinal instrumentation for spondylodiskitis (SD) remains highly controversial. To date, surgical data are limited to relatively small case series with short-term follow-up data. In this study, we wanted to elucidate the biomechanical, surgical, and neurologic long-term outcomes in these patients. MATERIAL AND METHODS: A retrospective analysis from two German primary care hospitals over a 9-year period (2005-2014) was performed. The inclusion criteria were (1) pyogenic lumbar SD, (2) minimum follow-up of 1 year, and (3) surgical instrumentation. The clinical and radiologic outcome was assessed before surgery, at discharge, and at a minimum of 12 months of follow-up. Follow-up included physical examination, laboratory results, CT and MRI scans, as well as assessment of quality of life (QoL) using short-form health survey (SF-36) inventory, Oswestry Disability Questionnaire, and visual analog scale (VAS) spine score. RESULTS: Complete data were available in 70 patients (49 males and 21 females, with an age range of 67±12.3 years) with a median follow-up of 6.6 ± 4.2 years. Follow-up data were available in 70 patients after 1 year, in 58 patients after 2 years, and in 44 patients after 6 years. Thirty-five patients underwent posterior stabilization and decompression alone and 35 patients were operated on in a two-stage 360-degree interbody fusion with decompression. Pre- and postoperative angles of the affected motion segment were 17.6 ± 10.2 and 16.1 ± 10.7 degrees in patients with posterior instrumentation only and 21.0 ± 10.2 and 18.3 ± 10.5 degrees in patients with combined anterior/posterior fusion. Vertebral body subsidence was seen in 12 and 6 cases following posterior instrumentation and 360-degree instrumentation, respectively. Nonfusion was encountered in 22 and 11 cases following posterior instrumentation and 360-degree instrumentation, respectively. The length of hospital stay was 35.0 ± 24.5 days. Surgery-associated complication rate was 18% (12/70). New neurologic symptoms occurred in 7% (5/70). Revision surgery was performed in 3% (2/70) due to screw misplacement/hardware failure and in 3% (2/70) due to intraspinal hematoma. Although patients reported a highly impaired pain deception and vitality, physical mobility was unaffected and pain disability during daily activities was moderate. CONCLUSION: Surgical treatment of SD with a staged surgical approach (if needed) is safe and provides very good long-term clinical and radiologic outcome.

Surgical treatment of Duchenne muscular dystrophy patients in Germany: the present situation.

In 1988, we familiarised ourselves at Poitiers with the concept of operative treatment of the lower limbs and the spine in Duchenne muscular dystrophy (DMD) patients which Yves Rideau and his collaborators had developed there in the early 1980s. Thereupon, we immediately established the techniques at our home universities, first at the Technische Universität Aachen and, from 1999 on, at the Universitätsklinikum Erlangen, Germany. Since then, we have applied the technique to more than 500 DMD patients in total by performing more than 800 operations on the lower limbs and/or spine. In support of findings reported by Professor Rideau in this issue we observed that, where patients are still ambulatory at the time of operation, the operation delays the point at which patients become wheelchair-bound by about two years. Likewise, patients receiving this treatment were/are also able to perform the Gowers' manoeuvre for around two years longer.

Periacetabular cortical and cancellous bone mineral density loss after press-fit cup fixation: a prospective 7-year follow-up.

The impact of total hip arthroplasty on strain adaptive bone remodeling has been extensively analyzed by dual-energy x-ray absorptiometry. In this study, we present a prospective computed tomography-assisted study of periacetabular cortical and cancellous bone mineral density (in milligrams of calcium hydroxyapatite [CaHA] per milliliter, or mgCaHA/mL) changes 10 days and 1, 3, and 7 years after press-fit cup implantation for 38 hips in vivo. Cancellous bone mineral density decreased by Ø -63% ventral and Ø -85% dorsal to the cup; cortical bone mineral density, by Ø -22% ventral and Ø -18% dorsal to the cup. The presented periacetabular strain adaptive bone mineral density data are the most extensive of the current literature. Even the measured extensive cancellous bone mineral density loss was thus far of no clinical relevance because all cups showed radiographic signs of stable ingrowth.

Operative treatment of scoliosis in proximal spinal muscular atrophy: results of 41 patients.

INTRODUCTION: The early development of progressive scoliosis with pelvic obliquity is the most significant orthopaedic problem for non-ambulatory children with spinal muscular atrophy (SMA). PATIENTS: 24 SMA patients were operated on for scoliosis using the ISOLA(®) system and 17 patients using a telescopic rod. The average age at spinal surgery was 12.3 years (6.5-22.7) in the ISOLA(®) group and 6.7 years (4.8-10.9) in the telescopic rod group. RESULTS: The Cobb angle was corrected on average from pre-operative 83°(54°-120°) to post-operative 39°(5°-70°) in the ISOLA(®) group and, respectively, from 62°(28°-86°) to 18°(0°-34°) in the telescopic rod group. Mean loss of correction at mean follow-up of 6 years (3-10) was 6°(0°-33°) in the ISOLA(®) group and at mean follow-up of 8.6 years (3-12) 13°(0°-49°) in the telescopic rod group excluding the patients with rod failure. The vital capacity is not worsened by these operations in comparison to the natural course. After telescopic rods were implanted, there were some unsatisfactory results due to crankshaft phenomenon and an increase of pelvic obliquity. CONCLUSION: Our recommendation for non-ambulatory SMA patients is to have definitive stabilisation using multisegmental instrumentation, starting from the age of 10 to 12 years.