Paul Alfred Grützner

The accuracy of free-hand cup positioning - a CT based measurement of cup placement in 105 total hip arthroplasties

We studied 105 patients who received a total hip arthroplasty between June 1985 and August 2001 using freehand positioning of the acetabular cup. Using pelvic CT scan and the hip-plan module of SurgiGATE-System (Medivision, Oberdorf, Switzerland), we measured the angles of inclination and anteversion of the cup. Mean inclination angle was 45.8°±10.1° (range: 23.0–71.5°) and mean anteversion angle was 27.3°±15.0° (range: −23.5° to 59.0°). We compared the results to the “safe” position as defined by Lewinnek et al. and found that only 27/105 cups were implanted within the limits of the safe position. We conclude that a safe position as defined by Lewinnek et al. [13] was only achieved in a minority of the cups that were implanted freehand.RésuméNous avons étudié 105 malades qui ont eu une Arthroplastie Totale de la Hanche entre juin 1985 et août 2001 avec positionnement manuel de la cupule acétabulaire. Utilisant une tomodensitométrie pelvienne et le module de hanche de SurgiGATE© - System (Medivision, Oberdorf, Suisse) nous avons mesuré les angles d’inclination et d’antéversion de la cupule. L’angle moyen d’inclination était 45.8°±10.1° (gamme: 23.0° à 71.5°) et l’angle moyen d’antéversion était 27.3°±15.0° (gamme: -23.5° à 59.0°). Nous avons comparé les résultats à l’orientation de sécurité définie par Lewinnek et al. et nous avons trouvé que seulement 27/105 cupules ont été implantées dans les limites de l’orientation correctes. Nous concluons qu’une orientation de sécurité, comme défini par Lewinnek et al. [13] n’a été obtenue que dans une minorité des cupules implantées manuellement.

Intraoperative Three-dimensional Imaging in the Treatment of Acute Unstable Syndesmotic Injuries

BACKGROUND Acute unstable syndesmotic ankle injuries are treated primarily by reduction and stabilization with a syndesmotic screw. Examination with fluoroscopy or standard radiographs may not provide reliable information about the quality of the reduction. There is evidence that intraoperative three-dimensional imaging can demonstrate a large proportion of malreductions. The aim of this study was to determine whether intraoperative three-dimensional imaging improves the detection of inadequate positioning of the distal aspect of the fibula in the tibiofibular incisura after syndesmotic screw insertion compared with the findings on standard intraoperative fluoroscopy. METHODS Of 2286 ankle fractures treated operatively from August 2001 to February 2011, 251 consecutive cases (11%) were identified in a retrospective chart review. All had an unstable syndesmosis and underwent syndesmosis stabilization on the basis of an intraoperative hook test. After fluoroscopy, an intraoperative three-dimensional scan was performed. The result of this scan was documented by the surgeon and analyzed retrospectively with regard to the incidence and nature of the need for intraoperative revisions. RESULTS The intraoperative three-dimensional scan altered the surgical outcome in eighty-two ankles (32.7%). In most ankles (seventy-seven; 30.7%), the reduction was improved, with the most common improvement being the alignment of the fibula in the tibiofibular incisura in sixty-four patients (25.5%) followed by correction of the fracture reduction in thirteen patients (5.2%). The other five alterations involved implant corrections. The most common malpositions requiring correction after insertion of a positioning screw, with or without additional fixation, were anterior displacement and internal rotation of the distal aspect of the fibula. CONCLUSIONS Following open reduction and internal fixation of an ankle fracture, the correct position of the syndesmosis cannot be evaluated reliably with use of conventional radiographs or intraoperative fluoroscopy. In view of the high proportion of positive findings in this study, we believe that any treatment of a syndesmotic injury should include intraoperative three-dimensional imaging or at least a postoperative computed tomography scan.

Cigarette smoking influences the clinical and occupational outcome of patients with tibial shaft fractures.

Tibial shaft fracture is one of the most common types of bone fracture in young patients. In this prospective clinical cohort study, we investigated the effects of cigarette smoking on the clinical, functional, psychosocial and occupational outcomes after isolated lower-leg fracture. We examined 85 patients, including 61 men and 24 women, with a collective mean age of 46 years (range: 18-84 years). Thirty-nine patients had never smoked (G1) and 45 patients were current or previous smokers (G2). The G2 group displayed a significantly increased risk for delayed union or nonunion (G1=3 patients, G2=18 patients; P=0.0007) and increased time required for fracture healing (mean times: G1=11.9 weeks, G2=17.4 weeks; p=0.003) and a markedly increased time out of work (mean times: G1=16.1 weeks, G2=21.5 weeks; p=0.1177 (not significant)). The 18 negatively affected patients in G2 displayed a significant increase in the time required for fracture healing and time out of work (26 weeks (p=0.02) and 31 weeks (p=0.03), respectively). G2 group members had a 3- to 18-fold higher risk of impaired bone healing. The mean Short Form 36 (SF-36) was similar in both groups. The physical-function scores were G1=49.6 and G2=48.6; the mental scores were G1=52.7 and G2=52.8. These findings indicate that smoking significantly increases the risk of impaired fracture healing, which has clinical and occupational consequences for the affected patients. Based on our data, we developed a score to estimate the individual risk of impaired fracture healing. These types of patients must be informed and closely monitored to determine the need for timely re-intervention with additional therapy, such as BMP s or ultrasound.

Opening-Wedge High Tibial Osteotomy with a Locked Low-Profile Plate

BACKGROUND High tibial osteotomy has been recognized as a beneficial treatment for osteoarthritis of the medial compartment of the knee. The purpose of this prospective study was to assess the short-term results of opening-wedge high tibial osteotomies with locked plate fixation. METHODS From September 2002 to November 2005, fifty-one consecutive medial opening-wedge high tibial osteotomies were performed. The mean age of the patients at the time of the index operation was forty-nine years. The preoperative and postoperative factors analyzed included the grade of arthritis of the tibiofemoral compartment (the Ahlbäck radiographic grade), the anatomic tibiofemoral angle, patellar height, the Hospital for Special Surgery rating system score, and the Lysholm and Gillquist knee score. RESULTS Postoperatively, one superficial wound infection occurred. Fifty of the fifty-one osteotomies healed after an average period of 12.9 weeks (range, eight to sixteen weeks) without bone grafts. A nonunion developed in a sixty-two-year-old patient who was a cigarette smoker. The average postoperative tibiofemoral angle was 9 degrees of valgus. Forty-nine patients were followed for a mean of fifty-two months. The average score on the Hospital for Special Surgery rating system was 86 points at the time of the most recent follow-up. The rating was excellent in twenty-eight patients (57%), good in twelve (24%), fair in four (8%), and poor in five (10%). The average score on the Lysholm and Gillquist knee-scoring scale was 83 points. According to these scores, the outcome was excellent in nine patients (18%), good in thirty-one (63%), fair in three (6%), and poor in six (12%). Four knees failed after an average of thirty-six months. CONCLUSIONS Our results suggest that an opening-wedge high tibial osteotomy with locked plate fixation allows a correct valgus angle to be achieved with good short-term results.

Computer-assistierte perkutane Verschraubung des hinteren Beckenrings Erste Erfahrungen mit einem Bildwandler basierten optoelektronischen Navigationssystem

ZusammenfassungBei Verletzungen des Beckenrings mit kombinierter vorderer und hinterer Instabilität, Typ C nach der AO Klassifikation, ist sowohl die Stabilisierung des vorderen als auch des hinteren Beckenrings indiziert. Bei alleiniger Beteiligung der Bandverbindungen stellt die transileosacrale Schraubenosteosynthese eine biomechanisch günstige, gering invasive Methode dar. Die Probleme dieser Methode liegen in der korrekten Schraubenplatzierung. Die Schraubenposition muss intraoperativ in 3 Ebenen kontrolliert werden (Inletview, Outletview und lateral). Daher ist die konventionelle Technik in der Regel mit einer hohen intraoperativen Strahlenexposition verbunden.In der vorliegenden Arbeit wird die Technik der exakten transileosacralen Schraubenplatzierung mit einem passiven optoelektronischen Navigationssystem, basiert auf Bildverstärkerdaten, gezeigt. In das System ist ein präkalibrierter navigierter Bildverstärker implementiert. Nach dem Anbringen der Referenzbasis am Patienten werden BV-Bilder in inlet-, outlet- und lateraler Projektion aufgenommen und in den Navigationsrechner geladen. Diese werden unter Verwendung eines speziellen mathematischen Algorithmus entzerrt. Anschließend kann die Schraubenplatzierung mit kalibrierten Instrumenten erfolgen. Die Instrumente werden in den BV-Bildern in bis zu 4 Ebenen gleichzeitig visualisiert, was der Situation des Einsatzes von 4 Bildverstärkern im konstanten Modus entsprechen würde. Somit ist keine weitere BV-Zeit ist erforderlich. Nach erfolgten Repositionsmanövern können bei entsprechender Veränderung der Anatomie intraoperativ neue Bilder zur Navigation aufgenommen werden.Aufgrund der unmittelbaren intraoperativen Verfügbarkeit und dem jederzeit möglichen Positionsupdate wenden wir die bildwandlergestützte Navigation bei frischen Verletzungen an. Zwischen Oktober 1999 und Dezember 2000 wurde bei 7 Patienten mit traumatischer Instabilität eine computerassistierte, perkutane, transileosacrale Verschraubung des hinteren Beckenrings durchgeführt. In allen Fällen erfolgte die Verschraubung des IS-Gelenkes mit 2 kanülierten AO 7,3 mm Titanschrauben. Postoperativ wurde die die Implantatlage im CT kontrolliert. Die Position wurde mit den intraoperativ erstellten Protokollen verglichen. Bei keinem Patienten trat eine Infektion auf. Postoperativ wurden keine neurologischen Ausfälle festgestellt. In der postoperativ durchgeführten Computertomographie ließ sich keine Fehlplatzierung intraspinal oder intraforaminal nachweisen. In 2 Fällen trat eine tangentiale Penetration des Schraubengewindes an der ventralen Sakrumbegrenzung auf.Die hier vorgestellten ersten Erfahrungen zeigen Vorteile bei der klinischen Anwendung eines bildwandlergestützten optoelektronischen Freihandnavigationssystems zur Platzierung iliosakraler Schrauben.AbstractInjuries of the posterior pelvic with combined anterior and posterior instability require the stabilisation of both the anterior and posterior pelvic ring. If the injury only involves the ligamental connections, then a transileosacral osteosynthesis with screws is the minimal invasive and biomechanically suitable method of choice.The difficulty with this approach is the correct placement of the screws. Their position must be monitored intraoperatively in 3 planes (inlet, outlet and lateral viewing). This denotes that conventional methods involve high radiation dosages for the patient and the surgical staff.Having the system readily available and being able to perform updates during the operation, fluoroscopically supported navigation for the treatment of fresh injuries becomes possible.Between October 1999 and December 2000 7 patients with traumatic instability of the posterior pelvic ring were treated by computer assisted percutaneous transileosacral screw osteosynthesis. In each case the osteosynthesis of the ileosacral joint was performed with two cannulated AO 7,3 mm titanium screws. After the operation the screw position was controlled by CT scanning and compared to the data acquired intraoperatively. No patients had infection, and there were no postoperative neurological defects. The postoperative CT scans showed no intraspinal or intraforaminal malplacement of the screws. In two cases a slight tangential screwthread penetration through the ventral sacrum was found.Our first experiences with this novel technology are encouraging and clearly demonstrate the advantages of fluoroscopic supported passive navigation systems for the optimal placement of ileosacral screws.

Cigarette smoking decreases TGF-β1 serum concentrations after long bone fracture

TGF-b1 serum concentrations are considered to be one of the most promising markers of fracture healing. Previously, we demonstrated significant differences in the post-traumatic time courses of patients with timely and delayed fracture healing. The aim of this study was to evaluate possible differences in the serum concentrations of TGF-b1 in cigarette-smoking vs. non-smoking patients with timely and delayed fracture healing in order to understand pathophysiological pathways through which smoking impairs fracture healing.Serum samples were collected from 248 patients undergoing surgical treatment for long bone fractures within 1 year of surgery. Samples from 14 patients with atrophic-type delayed fracture healing were compared with 14 matched patients with normal bone healing. Each group included seven smokers and seven non-smokers. Post-operative serum concentrations were analysed at 1, 2, 4, 8, and 12 weeks as well as 1 year after surgery. The patients were monitored both clinically and radiologically for the entire duration of the study.All patients increased TGF-b1 serum concentrations after surgery. In patients with normal fracture healing, significantly higher TGF-b1 levels were observed in non-smokers (70 ng/ml) than in smokers(50 ng/ml) at the 4th week after surgery (p = 0.007). Also at the 4th week, in patients with delayed healing, significantly lower TGF-b1 levels were observed in smokers than in non-smokers (38 ng/ml vs.47 ng/ml, p = 0.021). However, no significant differences between non-smokers with delayed healing and smokers with normal healing (p = 0.151) were observed at the 4th week after surgery. TGF-b1 serum concentrations reached a plateau in all groups from the 6th to the 12th week after surgery, with a slight decrease observed in the final measurement taken 1 year after surgery.This study demonstrates that, after fracture, TGF-b1 serum concentrations are reduced by smoking,and this reduction is statistically significant during the 4th week after surgery. Our findings may help reveal the mechanism by which smoking impairs fracture healing. Furthermore, these results may help to establish a serological marker that predicts impaired fracture healing soon after the injury. Surgeons will not only be able to monitor the bone healing, but they will also be able to monitor the success of additional treatments such as ultrasound and bone morphologic proteins (BMPs).

TRACP 5b and CTX as osteological markers of delayed fracture healing

Radiological studies are the standard method to monitor fracture healing but they do not allow a timely assessment of bone healing. Biochemical markers react rapidly to changes in bone metabolism during fracture healing and could be an additional tool to monitor this process. The goal of this study was to observe changes in serum biomarkers and evaluate the possible differences in the serum levels of tartrate-resistant acid phosphatase 5b (TRACP 5b), total N-terminal propeptide of type I collagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal cross-linking telopeptide of type I collagen (CTX) in patients with normal and delayed fracture healing. Several serum samples were collected for one year after the surgical treatment of long bone fractures in 248 patients. From this large pool, 15 patients with atrophic nonunion were matched to 15 patients with normal bone healing. Post-operative changes in osteological markers were monitored during the 1st, 2nd, 4th, 8th, 12th and 52nd weeks. The patients were followed both clinically and radiologically for the entire one-year duration of the study. In the first week, the absolute values of CTX decreased significantly (p=0.0164) in cases of delayed fracture healing. The relative values of TRACP 5b were significantly decreased at weeks 4 (p=0.0066) and 8 (p=0.0043). BAP and PINP levels decreased in the first week followed by an increase, but there were no significant differences in the absolute or relative values during the healing process in both patient groups. For the first time, we have demonstrated changes in serum concentrations of TRACP 5b, PINP, BAP, and CTX during normal and delayed fracture healing. Characteristic changes in systemic TRACP 5b and CTX levels could reflect the initial process of successful fracture healing and may be used in clinical practice to monitor the healing process. Furthermore, it could be very important for determining the beneficial effects of additional treatments such as ultrasound or BMPs in clinical trials.

Automatic X-ray landmark detection and shape segmentation via data-driven joint estimation of image displacements

In this paper, we propose a new method for fully-automatic landmark detection and shape segmentation in X-ray images. To detect landmarks, we estimate the displacements from some randomly sampled image patches to the (unknown) landmark positions, and then we integrate these predictions via a voting scheme. Our key contribution is a new algorithm for estimating these displacements. Different from other methods where each image patch independently predicts its displacement, we jointly estimate the displacements from all patches together in a data driven way, by considering not only the training data but also geometric constraints on the test image. The displacements estimation is formulated as a convex optimization problem that can be solved efficiently. Finally, we use the sparse shape composition model as the a priori information to regularize the landmark positions and thus generate the segmented shape contour. We validate our method on X-ray image datasets of three different anatomical structures: complete femur, proximal femur and pelvis. Experiments show that our method is accurate and robust in landmark detection, and, combined with the shape model, gives a better or comparable performance in shape segmentation compared to state-of-the art methods. Finally, a preliminary study using CT data shows the extensibility of our method to 3D data.

Computer-assisted LISS plate osteosynthesis of proximal tibia fractures: Feasibility study and first clinical results

Fluoroscopy is the most common tool for the intraoperative control of long-bone fracture reduction. Limitations of this technology include high radiation exposure for the patient and the surgical team, limited visual field, distorted images, and cumbersome verification of image updating. Fluoroscopy-based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. Existing fluoroscopy-based navigation systems are still limited as far as the virtual representation of true surgical reality is concerned. This article, for the first time, presents a reality-enhanced virtual fluoroscopy with radiation-free updates of in situ surgical fluoroscopic images to control metaphyseal fracture reduction. A virtual fluoroscopy is created using the projection properties of the fluoroscope; it allows the display of detailed three-dimensional (3D) geometric models of surgical tools and implants superimposed on the X-ray images. Starting from multiple registered fluoroscopy images, a virtual 3D cylinder model for each principal bone fragment is constructed. This spatial cylinder model not only supplies a 3D image of the fracture, but also allows effective fragment projection recovery from the fluoroscopic images and enables radiation-free updates of in situ surgical fluoroscopic images by non-linear interpolation and warping algorithms. Initial clinical experience was gained during four tibia fracture fixations that were treated by LISS (Less Invasive Stabilization System) osteosynthesis. In the cases operated on, after primary image acquisition, the image intensifier was replaced by the virtual reality system. In all cases, the procedure including fracture reduction and LISS osteosynthesis was performed entirely in virtual reality. A significant disadvantage was the unfamiliar operation of this prototype software and the need for an additional operator for the navigation system.

Operative treatment of distal femoral fractures above total knee arthroplasty with the indirect reduction technique: a long-term follow-up study.

The complication rate of conventional plate osteosynthesis (CPO) of periprosthetic femoral fractures above total knee arthroplasties (TKA) is high. Indirect reduction techniques were introduced to reduce surgical dissection at the fracture site. Twenty-one patients (4 men and 17 women) with femoral fractures above well-fixed total knee arthroplasties were consecutively treated with the indirect reduction technique. AO/ASIF (Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of the Problems of Internal Fixation) Type 33A fractures were included. The mean age was 78 years (range, 67-94 years). Four fractures were stabilised with bone grafts, three in combination with bone cement. Nineteen of the patients were seen at a 1-year follow-up, 15 were seen after a long-term follow-up of 9 years (range, 7-12 years). There was only one implant failure in a comminuted fracture with severe osteoporosis, no infection, and no non-union. At the 1-year follow-up malalignment of 5 degrees varus occurred in one patient. The mean range of motion of the eighteen patients was 98 degrees (range, 65-110 degrees). The mean knee society score was 74 (range, 62-84), the mean function score was 52 (range, 39-72). At the long-term follow-up, the mean range of motion of the patients was 101 degrees (range, 65-115 degrees). The mean knee society score was 77 (range, 65-88), the mean function score was 55 (range, 40-75). Our results suggest the 95 degrees condylar blade plate in the indirect reduction technique is still a good implant with good long-term results. It works best in proximal fractures when there is minimal comminution of the distal fragment in the hands of an experienced trauma surgeon. Knee function and range of motion increased less over time.