Björn Gunnar Ochs

Changes in the treatment of acetabular fractures over 15 years: Analysis of 1266 cases treated by the German Pelvic Multicentre Study Group (DAO/DGU)

Epidemiological, clinical and radiological data of 1266 patients with a unilateral acetabular fracture of up to 29 hospitals was reviewed. Three time periods, 1991-1993 (Registry I; n=359), 1998-2000 (Registry II; n=503), and 2005-2006 (Registry III; n=404) were compared with regard to injury pattern and severity, fracture type, and chosen nonoperative vs. operative treatment to elucidate changes over time in the treatment of acetabular fractures. In the operatively treated group, time to operation, surgical approach, fracture fixation implants and fracture reduction quality were examined. 641 (50.6%) patients with isolated acetabular fractures, 410 (32.4%) multiple injured and 215 (17.0%) polytrauma patients with 642 (50.7%) simple and 624 (49.3%) associated acetabular fractures were evaluated. In the time period from 1991 to 2006, the rate of operative treatments increased nationwide to 77% (rho<0.001). The distribution of fracture types involving the anterior and posterior wall changed with age (rho<0.001). Across all registries, 583 (68.0%) operations were performed within 7 days, 212 (24.7%) operations between 7 and 14 days and 54 (6.3%) operations were performed later than 14 days after injury. An anatomical reduction (0-1mm displacement) was achieved in 551 (64%) acetabular fractures. The obtained reduction quality did not correlate with time to operation, was lower in associated than in simple fracture types, and also lower in patients with isolated acetabular fractures than in polytrauma patients. Most importantly, the fracture reduction quality did not improve over time despite a higher frequency of surgical interventions. The Kocher-Langenbeck approach was preferred in the nineties in nearly three quarters of all operative procedures. Currently, the Kocher-Langenbeck and the ilioinguinal approaches are used equally often. The fracture fixation did not change over time and is achieved in 51% with plates in combination with single screws. This multisurgeon series illustrates a nationwide performance in acetabular fracture management. Despite changes in the chosen approaches and an increased surgical frequency, the operative treatment of acetabular fractures of the last 15 years did not lead to an increased reduction quality. Therefore, the rarity and complexity of acetabular fractures demands further specific teaching by experienced acetabular surgeons, scientific research and clinical outcome evaluation.

Remodeling of Articular Cartilage and Subchondral Bone After Bone Grafting and Matrix-Associated Autologous Chondrocyte Implantation for Osteochondritis Dissecans of the Knee

Background: Osteochondritis dissecans (OCD) of the knee is a challenging problem. Previously, the authors implemented a novel 1-step surgical procedure for OCD treatment consisting of matrix-associated autologous chondrocyte implantation (ACI) and simultaneous bone reconstruction including the subchondral lamina. Purpose: This study presents the 2-to 5-year results after this technique, assessing correlations of clinical function and cartilage and bone remodeling processes. Study Design: Case series; Level of evidence, 4. Methods: Twenty-six patients with symptomatic condylar knee OCD (International Cartilage Repair Society OCD III/IV) were treated with matrix-associated ACI and monocortical cancellous cylinders for defect filling and subchondral bone plate reconstruction using cortical graft layers as novel subchondral lamina. Evaluations were performed with clinical rating scales and 1.5-T magnetic resonance imaging using the magnetic resonance observation of cartilage repair tissue (MOCART) score and a newly implemented subchondral lamina remodeling grade. Results: The defect size was 5.3 ± 2.3 cm2. The defect depth was 8.7 ± 2.4 mm. After a follow-up of 39.8 ± 12.0 months, all scores improved significantly. Nineteen patients (73%) reached good/excellent results in the Lysholm-Gillquist score (preoperatively: 53.2 ± 18.0 points; latest follow-up: 88.5 ± 9.5 points) and the Cincinnati knee rating score (preoperatively: 51.7 ± 13.0 points; latest follow-up: 84.6 ± 11.7 points) and significant improvements in the subjective International Knee Documentation Committee (IKDC) score by 27.9% (preoperatively: 50.5% ± 16.1%; latest follow-up: 78.4% ± 13.4%). The MOCART score reached 62.4 ± 18.9 points. The clinical improvement and tissue remodeling occurred simultaneously and timed; thus, the cartilage defect filling and the lamina remodeling grades correlated significantly with each other, the follow-up time, and almost all clinical scores. Conclusion: The simultaneous reconstruction of deep osteochondral defects of the knee OCD with monocortical cancellous cylinders and matrix-associated ACI is a biological, 1-step alternative to osteochondral cylinder transfer or conventional ACI that leads to good clinical and magnetic resonance imaging results after an intermediate follow-up period. The present study demonstrated simultaneous remodeling processes of articular cartilage repair tissue and subchondral lamina; this synchronization is not yet understood and deserves further investigation.

Computer-assisted periacetabular screw placement: Comparison of different fluoroscopy-based navigation procedures with conventional technique

The current gold standard for operatively treated acetabular fractures is open reduction and internal fixation. Fractures with minimal displacement may be stabilised by minimally invasive methods such as percutaneous periacetabular screws. However, their placement is a demanding procedure due to the complex pelvic anatomy. The aim of this study was to evaluate the accuracy of periacetabular screw placement assessing pre-defined placement corridors and comparing different fluoroscopy-based navigation procedures and the conventional technique. For each screw an individual periacetabular placement corridor was preoperatively planned using the planning software iPlan CMF(©) 3.0 (BrainLAB). 210 screws (retrograde anterior column screws, retrograde posterior column screws, supraacetabular ilium screws) were placed in an artificial Synbone pelvis model (30 hemipelves) and in human cadaver specimen (30 hemipelves). 2D- and 3D-fluoroscopy-based navigation procedures were compared to the conventional technique. Insertion time and radiation exposure to specimen were also recorded. The achieved screw position was postoperatively assessed by an Iso-C(3D) scan. Perforations of bony cortices or articular surfaces were analysed and the screw deviation severity (difference of the operatively achieved screw position and the preoperatively planned screw position in reference to the pre-defined corridors) was determined using image fusion. Using 3D-fluoroscopy-based navigation, the screw perforation rate (7%) was significantly lower compared to 2D-fluoroscopy-based navigation (20%). For all screws, the deviation severity was significantly lower using a 3D- compared to a 2D-fluoroscopy-based navigation and the conventional technique. Analysing the posterior column screws, the screw deviation severity was significantly lower using 3D- compared to 2D-fluoroscopy-based navigation. However, for the anterior column screw, the screw deviation severity was similar regardless of the imaging method. Despite the advantages of the 3D-fluoroscopy-based navigation, this method led to significantly longer total procedure and fluoroscopic times, and the applied radiation dose was significantly higher. Percutaneous periacetabular screw placement is demanding. Especially for posterior column screws, due to a lower perforation rate and a higher accuracy in periacetabular screw placement, 3D-fluoroscopy-based navigation procedure appears to be the method of choice for image guidance in acetabular surgery.

Acetabular bone reconstruction in revision arthroplasty: A COMPARISON OF FREEZE-DRIED, IRRADIATED AND CHEMICALLY-TREATED ALLOGRAFT VITALISED WITH AUTOLOGOUS MARROW VERSUS FROZEN NON-IRRADIATED ALLOGRAFT

Deficiencies of acetabular bone stock at revision hip replacement were reconstructed with two different types of allograft using impaction bone grafting and a Burch-Schneider reinforcement ring. We compared a standard frozen non-irradiated bone bank allograft (group A) with a freeze-dried irradiated bone allograft, vitalised with autologous marrow (group B). We studied 78 patients (79 hips), of whom 87% (69 hips) had type III acetabular defects according to the American Academy of Orthopaedic Surgeons classification at a mean of 31.4 months (14 to 51) after surgery. At the latest follow-up, the mean Harris hip score was 69.9 points (13.5 to 97.1) in group A and 71.0 points (11.5 to 96.5) in group B. Each hip showed evidence of trabeculation and incorporation of the allograft with no acetabular loosening. These results suggest that the use of an acetabular reinforcement ring and a living composite of sterile allograft and autologous marrow appears to be a method of reconstructing acetabular deficiencies which gives comparable results to current forms of treatment.

Proximal humeral fractures in children and adolescents.

Background: The purpose of the study was to investigate possible reasons for the failure of closed reduction of proximal humerus fractures in children and adolescents. We assessed the rate of soft tissue entrapment, and we also investigated the long-term clinical and radiological results after an age- and deformity-focused treatment regimen according to national guidelines. Methods: Forty-three patients were included in the study. Ten (mean age, 12.4 years; range, 6-16 years) of the patients were treated conservatively. The remaining 33 patients (mean age, 14 years; range, 6-18 years) were treated surgically (n = 2 Neer grade 2, n = 16 Neer grade 3, and n = 15 Neer grade 4) with either closed (n = 16) or open reduction with internal fixation. In 17 fractures, closed anatomical reduction of the fracture under general anesthesia was not possible. Subsequent open reduction and Kirschner wire or screw fixation (n = 12) or plate fixation (n = 5) was necessary. In 9 of these 17 fractures (5 fractures were totally displaced fractures), closed reduction was impossible because of the entrapment of periost (n = 2) or the biceps tendon with parts of the periost (n = 7). At follow-up, the clinical assessment included a structured interview, a detailed physical examination, and the assessment of overall shoulder function with the Constant score. Results: Operative and postoperative complications did not occur. All surgically treated fractures anatomically reduced and healed without loss of reduction. At a mean follow-up of 39 months (range, 12-118 months), all patients who were evaluated had excellent results according to the Constant score and had a normal range of motion and excellent strength of the shoulder joint. Conclusions: A failed closed reduction should be interpreted as a possible soft tissue entrapment most likely because of the long biceps tendon. Those cases should be addressed with open reduction and removal of the entrapped structures. If anatomical reduction is achieved and maintained until fracture healing, excellent functional and radiological results can be expected from an age- and deformity-focused treatment regimen for children and adolescents with proximal humeral fractures. Level of Evidence: Level 4 (Therapeutic study).

BMP9 a possible alternative drug for the recently withdrawn BMP7? New perspectives for (re-)implementation by personalized medicine.

Promotion of rhBMP2 and rhBMP7 for the routine use to support fracture healing has been hampered by high costs, safety concerns and reasonable failure rates, imposing restrictions in its clinical use. Since there is little debate regarding its treatment potential, there is rising need for a better understanding of the mode of action of these BMPs to overcome its drawbacks and promote more efficacious treatment strategies for bone regeneration. Recently, BMP9, owing to its improved osteogenic potential, is gaining attention as a promising therapeutic alternative. Our study aimed at identifying specific gene expression patterns which may predict and explain individual responses to rhBMP7 and rhBMP9 treatments. Therefore, we investigated the effect of rhBMP7 and rhBMP9 on primary human osteoblasts from 110 donors and corresponding THP-1-derived osteoclasts. This was further compared with each other and our reported data on rhBMP2 response. Based on the individual donor response, we found three donor groups profiting from rhBMP treatment either directly via stimulation of osteoblast function or viability and/or indirectly via inhibition of osteoclasts. The response on rhBMP7 treatment correlated with expression levels of the genes BAMBI, SOST, Noggin, Smad4 and RANKL, while the response of rhBMP9 correlated to the expression levels of Alk6, Endoglin, Smurf1, Smurf2, SOST and RANKL in these donors. Noteworthy, rhBMP9 treatment showed significantly increased osteogenic activity (AP activity and Smad nuclear translocation) when compared to the two clinically used rhBMPs. Based on patient’s respective expression profiles, clinical application of rhBMP9 either solely or in combination with rhBMP2 and/or rhBMP7 can become a promising new approach to fit the patient’s needs to promote fracture healing.

Refrakturen nach Entfernung von Osteosynthesematerialien

ZusammenfassungRefrakturen an den Extremitätenknochen nach Materialentfernung sind eine seltene, aber ernst zu nehmende Komplikation, die in den meisten Fällen einen weiteren Eingriff notwendig machen. In einer retrospektiven Analyse der eigenen Fälle sowie unter Berücksichtigung der vorhandenen Literatur zeigt sich, dass durch eine vollständige präoperative Diagnostik, durch Einhalten eines ausreichenden Intervalls von initialer Osteosynthese bis zur Materialentfernung, durch zurückhaltende Belastung des vorgeschädigten Knochens direkt nach der Materialentfernung und unter Berücksichtigung der Art der Frakturheilung die Komplikationsrate vermindert werden kann. Jedoch ist eine vollständige Vermeidung kaum möglich, da oft der ausdrückliche Wunsch des Patienten zur Materialentfernung vorhanden ist und biomechanisch eine Minderbelastbarkeit durch die residuellen Schraubenlöcher und die Demineralisationszonen im Bereich der ehemaligen Frakturzonen zumindest für einige Wochen postoperativ besteht. Entsprechend sollte in einigen Fällen die Empfehlung zum Verbleib des Osteosynthesematerials ausgesprochen werden.AbstractRefractures of long bones after implant removal are a rare but serious complication, which in most cases make a reoperation necessary. We analysed our own cases and reviewed the scarce literature on this subject. As a result we found that it is possible to reduce this complication by performing thorough preoperative preparation, observing an adequate interim time between initial osteosynthesis and hardware removal, cautiously exposing the weakened bone to force for a certain time period after implant removal and taking the character of the fracture healing into consideration. It is not possible to entirely eradicate this complication because a lot of patients demand the implant removal even though it is known that demineralisation and residual screw holes both induce a reduction of energy-absorbing capacity and therefore predispose the patient to refracture. In some cases the surgeon should recommend that the implants remain in situ.Refractures of long bones after implant removal are a rare but serious complication, which in most cases make a reoperation necessary. We analysed our own cases and reviewed the scarce literature on this subject. As a result we found that it is possible to reduce this complication by performing thorough preoperative preparation, observing an adequate interim time between initial osteosynthesis and hardware removal, cautiously exposing the weakened bone to force for a certain time period after implant removal and taking the character of the fracture healing into consideration. It is not possible to entirely eradicate this complication because a lot of patients demand the implant removal even though it is known that demineralisation and residual screw holes both induce a reduction of energy-absorbing capacity and therefore predispose the patient to refracture. In some cases the surgeon should recommend that the implants remain in situ.

Long-Term Results Using the Straight Tapered Femoral Cementless Hip Stem in Total Hip Arthroplasty: A Minimum of Twenty-Year Follow-Up

We report the first long-term results of a prospective cohort study after total hip arthroplasty using the cementless Bicontact hip stem. Between 1987 and 1990, 250 total hip arthroplasties in 236 patients were performed using the cementless Bicontact hip stem. The average follow-up was 22.8 years (20.4-24.8) and average age at index surgery was 58.1 years. Eighty-one patients died and 9 were lost to follow-up. We noted 11 stem revisions revealing an overall Kaplan Meier survival rate of 95.0% (CI 95%: 91.1-97.2%). The average Harris Hip Score revealed 81 points (range 24-93). The Bicontact hip stem demonstrated high survival rates despite high ages and osteopenic changes, which are equivalent to other long-term reports of cementless stem fixation.

Vergleich der Bildqualität zweier unterschiedlicher mobiler 3-dimensionaler Röntgen-C-Bögen mit einem konventionellen CT bei der Darstellung relevanter Strukturen am knöchernen Becken

AIM This study evaluated the image quality of two different cone beam CT scanners used in the operation theatre in pelvic trauma surgery in relation to their radiation dosage. Furthermore, the assumption that a higher dosage would result in better image quality was analysed by using the different acquisition scanner modes. MATERIAL AND METHODS We scanned the acetabulum (n=4) and iliosacral joints (n=4) of two human cadavers with a conventional CT and with two mobile cone beam CT scanners (Siemens Arcadis Orbic 3D and Ziehm Vision Vario 3D). With the two cone beam CT scanners (3D-BV), we used 6 different acquisition modes with different radiation dosages. The axial views of all scans were exported and blinded. Subsequently, the images were evaluated by 7 medical doctors with regard to identifiability of cortical structures (acetabular joint, fovea capitis femoris, cortical bone of the femur head, iliosacral joint, and sacral foramina), and the quality of the cancellous structure of the femur head. The evaluation was performed on axial views by using a defined five-point score. The interrater quality was statistically analysed according to Cohen with the kappa coefficient. In addition, the Wilcoxon test was used to identify significances between the 21 paired results of the evaluators. For determination of the signal-to-noise ratio, a Catphan 600 reference block with two different test elements (Teflon, PMP) was used. RESULTS Overall, the image quality of the conventional CT scans received the best score. Comparing the two 3D cone beams, the image quality of the Siemens Arcadis Orbic 3D in high-dosage mode received the best score (median: 2.40), the Ziehm Vision Vario 3D in low-dose mode without large patient key received the lowest score (median: 3.16). The differences in the 21 paired results of the two different acquisition modes were significant in 17 cases (p < 0.05) but the size of difference when comparing the different acquisition modes was almost always small. The interobserver agreement in one acquisition mode was low (kappa 0.008-0.134). The overall evaluation results of the same acquisition mode diverged by up to 2 score points. We noted a higher signal-to-noise ratio in the high dosage mode than in the low dosage mode. DISCUSSION When using intraoperative 3D imaging with the cone beam CT technique for pelvic injury, image acquisition in low-dose mode is adequate in terms of signal-to-noise ratio and image quality. The image quality does not correlate linearly with a higher radiation dosage. Therefore, the pelvic trauma surgeon using this technique is encouraged to gather his own experience with low dose modes thereby reducing patient radiation exposure.

Hardware removal after spinal instrumentation

Because of the increasing number of patients with surgically treated injuries of the spine we more often have to answer the question of indication for hardware removal. In the cervical spine and after anterior instrumentations of the thoracic and lumbar spine hardware removal is only indicated as part of the management of postoperative complications. After dorsal instrumentation for fractures of the thoracic and lumbar spine, implant-associated discomfort is possible. In addition, in non-fusion procedures there is the risk of implant failure. In these cases the hardware should be removed. If the consolidation of the fracture is in doubt, a preoperative CT scan is useful.