Steffen Schröter

High Complication Rate After Biplanar Open Wedge High Tibial Osteotomy Stabilized With a New Spacer Plate (Position HTO Plate) Without Bone Substitute

PURPOSE We performed a prospective clinical and radiographic evaluation after open wedge high tibial osteotomy (HTO) using the new Position HTO plate (Aesculap, Tuttlingen, Germany) without bone transplantation. METHODS Thirty-five open wedge HTOs with the Position HTO plate were performed without bone wedges. The mean patient age was 44.6 ± 9.2 years at the time of osteotomy, which was planned with mediCAD II software (Hectec, Niederviehbach, Germany). The Hospital for Special Surgery score, Lysholm-Gillquist score, Tegner activity level, and International Knee Documentation Committee subjective score were used for clinical assessment. We evaluated radiographs obtained preoperatively and at 2, 6, and 12 months postoperatively using full-weight-bearing anteroposterior whole-leg views and anteroposterior and lateral views of the knee. For statistical analyses, JMP 8.0.1 (SAS, Cary, NC) was used. RESULTS We observed an overall complication rate of 34% and a plate-related complication rate of 23%. Plate-related complications included loss of correction, fracture of the tibial plateau, screw failure, malunion, and fracture of the lateral cortical bone. A significant difference in the mechanical tibiofemoral angle of -1.3° ± 1.4° (P < .001) was found between the follow-up at 2 and 6 months. The mean Hospital for Special Surgery score was 74.8 ± 11.7 preoperatively, and it increased to 87.8 ± 11.0 (P < .001). The mean score on the Lysholm-Gillquist knee functional scoring scale was 55.5 ± 21.7 preoperatively, and it improved to 73.0 ± 23.9 (P < .001). The Tegner activity level was 2.6 ± 0.9 preoperatively, and it improved significantly at final follow-up to 3.7 ± 1.8 (P < .02). The International Knee Documentation Committee subjective score was 43.0 ± 14.9 preoperatively, and it increased to 66.1 ± 21 (P < .001). CONCLUSIONS We have shown a high plate-related complication rate and a significant loss of correction between 2 and 6 months of follow-up after open wedge HTO using the new Position HTO plate without bone wedges. The preoperatively planned mechanical tibiofemoral angle was not achieved. Despite these complications, the clinical outcome improved significantly. The Position HTO plate cannot be recommended with the presented technique. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Digital planning of high tibial osteotomy. Interrater reliability by using two different software

PurposeThe purpose of the study was to determine the interrater reliability as well as the correlation of mediCAD® and PreOPlan® in deformity analysis and digital planning of osteotomies.MethodsDigital radiographs were obtained from 81 patients planned to undergo an open wedge high tibial osteotomy. The JPEG files of the radiographs were imported to landmark-based software. Deformity analysis and planning of correction were performed by 1 experienced and 2 unexperienced observers. Osteotomy planning was aimed at correction to the predefined mechanical tibiofemoral angle of 3° valgus leg alignment. The interrater reliability of measurements was assessed using intraclass correlation coefficients (ICCs) and the confidence interval.ResultsThe ICC of PreOPlan® was from 0.841 (mechanical lateral distal femur angle) to 0.993 (wedge-angle) and from 0.896 (joint line convergence angle) to 0.995 (mechanical tibiofemoral angle) of mediCAD®. The ICC of height of wedge-base was 0.979 with PreOPlan® and 0.969 with mediCAD®. Comparing PreOPlan® and mediCAD®, the ICC of the height of wedge-base of the observers was 0.966, 0.956 and 0.969, respectively.ConclusionsThe results show a high interrater reliability of digital planning software. Experience of the observer had no influence on results. Furthermore, a high interrater reliability and correlation of digital planning specific parameters was found. Surgeons need to master limb geometry measurements and osteotomy planning on digital radiographs as digital planning reports are used for intercolleagual correspondence, teaching purposes and as medicolegal documents. The digital planning software tested agrees with the actual demands and could be recommended for deformity analysis and planning of osteotomies.Level of evidenceDiagnostic studies, Level I.

[Changes of patella position after closed and open wedge high tibial osteotomy: review of the literature].

AIM High tibial osteotomy (HTO) is an established treatment for varus osteoarthritis of the knee. The correction can be achieved by lateral closed wedge HTO or medial open wedge HTO techniques. Both techniques can change the patella position which influences alignment of the patella. Patella infera may compromise the result of secondary total knee prosthesis. An analysis of the current literature was carried out focusing on changes of patella position after HTO. METHOD A literature search was performed in PubMed which identified 15 relevant publications and the Insall-Salvati-index, the Blackburne-Peel-index and the Caton-Deschamps-index were analyzed. RESULTS Results after closed wedge HTO: the Insall-Salvati-index decreased in 7 papers, increased in 3 papers and was unchanged in 1 paper. The Blackburne-Peel-index increased in 5 papers and decreased in 2. The Caton-Deschamps-index decreased in 4 papers and increased in 2 papers. Results after open wedge HTO: the InsalI-Salvati-index decreased in 5 papers and increased in 2. The Blackburne-Peel-index decreased in all 7 papers and the Caton-Deschamps-index decreased in all 5 papers. The results of these studies vary significantly and there was a tendency to patella infera in both techniques. The Blackburne-Peel-index and the Caton-Deschamps-index may be biased by slope changes but the exact effect is not yet known. The Insall-Salvati-index seems to be independent of slope changes. The effect of different rehabilitation concepts on patella height is not known. CONCLUSION The clinical relevance of the observed changes in patella position must be clarified by prospective studies with strict criteria.

DLS 5.0 - The Biomechanical Effects of Dynamic Locking Screws

Introduction Indirect reduction of dia-/metaphyseal fractures with minimally invasive implant application bridges the fracture zone in order to protect the soft-tissue and blood supply. The goal of this fixation strategy is to allow stable motion at the fracture site to achieve indirect bone healing with callus formation. However, concerns have arisen that the high axial stiffness and eccentric position of locked plating constructs may suppress interfragmentary motion and callus formation, particularly under the plate. The reason for this is an asymmetric fracture movement. The biological need for sufficient callus formation and secondary bone healing is three-dimensional micro movement in the fracture zone. The DLS was designed to allow for increased fracture site motion. The purpose of the current study was to determine the biomechanical effect of the DLS_5.0. Methods Twelve surrogate bone models were used for analyzing the characteristics of the DLS_5.0. The axial stiffness and the interfragmentary motion of locked plating constructs with DLS were compared to conventional constructs with Locking Head Screws (LS_5.0). A quasi-static axial load of 0 to 2.5 kN was applied. Relative motion was measured. Results The dynamic system showed a biphasic axial stiffness distribution and provided a significant reduction of the initial axial stiffness of 74.4%. Additionally, the interfragmentary motion at the near cortex increased significantly from 0.033 mm to 0.210 mm (at 200N). Conclusions The DLS may ultimately be an improvement over the angular stable plate osteosynthesis. The advantages of the angular stability are not only preserved but even supplemented by a dynamic element which leads to homogenous fracture movement and to a potentially uniform callus distribution.

Veränderung der Patellahöhe nach „open“- und „closed wedge high tibial osteotomy“

AIM High tibial osteotomy (HTO) is an established treatment for varus osteoarthritis of the knee. The correction can be achieved by lateral closed wedge HTO or medial open wedge HTO techniques. Both techniques can change the patella position which influences alignment of the patella. Patella infera may compromise the result of secondary total knee prosthesis. An analysis of the current literature was carried out focusing on changes of patella position after HTO. METHOD A literature search was performed in PubMed which identified 15 relevant publications and the Insall-Salvati-index, the Blackburne-Peel-index and the Caton-Deschamps-index were analyzed. RESULTS Results after closed wedge HTO: the Insall-Salvati-index decreased in 7 papers, increased in 3 papers and was unchanged in 1 paper. The Blackburne-Peel-index increased in 5 papers and decreased in 2. The Caton-Deschamps-index decreased in 4 papers and increased in 2 papers. Results after open wedge HTO: the InsalI-Salvati-index decreased in 5 papers and increased in 2. The Blackburne-Peel-index decreased in all 7 papers and the Caton-Deschamps-index decreased in all 5 papers. The results of these studies vary significantly and there was a tendency to patella infera in both techniques. The Blackburne-Peel-index and the Caton-Deschamps-index may be biased by slope changes but the exact effect is not yet known. The Insall-Salvati-index seems to be independent of slope changes. The effect of different rehabilitation concepts on patella height is not known. CONCLUSION The clinical relevance of the observed changes in patella position must be clarified by prospective studies with strict criteria.

Precision in the Planning of Open Wedge HTO

INTRODUCTION The high tibial osteotomy (HTO) is regarded as an established method for varus deformity. To quantify the varus deformity, the anatomic and the mechanical leg axis can be determined. The success of HTO depends on the correct assessment of the preoperative axis deviation and the exact as planned correction. The aim of the retrospective study was to verify the accuracy (± 1.5° of mechanical tibiofemoral angle tolerance compared to the planning) with the preoperative planning compared to the postoperative result after correction using the TomoFix™ plate in open wedge HTO. MATERIALS AND METHOD A retrospective study of patients was carried out after open wedge HTO with the TomoFix™ plate. A full-weight bearing, long-standing anteroposterior radiograph of the whole lower extremity was performed before and after correction. The mechanical angles in the frontal plane were determined and compared with the plan as drawn. RESULTS The preoperative mechanical tibiofemoral angle (mTFA) was -5.33 ± 3.29° (varus) and at follow-up -0.3 ± 3.0° (varus). The mean correction was 4.9 ± 2.9°. The planned mTFA was 2.2 ± 1.6°(valgus). The corrected lower extremity showed a mean difference of -2.5 ± 3.4° in angle correction of the varus deformity as preoperatively assumed to be the optimal correction compared to the planning. The planning goal was not achieved in 73 % of the cases. CONCLUSION The results are comparable to those of other publications. However, taking into account the required accuracy of the drawn plan combined with the surgical precedure, it is not possible to achieve results within the desired tolerance.

Patellaluxation: Diagnostik- und Behandlungsalgorithmus unter Berücksichtigung der Torsion

BACKGROUND Patella dislocation and re-dislocation are common diseases. Although patella dislocation is frequent, it always poses a challenge concerning diagnostics and therapy. Mixed forms of pathological disorder in the patellofemoral joint make the analysis of the malalignment and the choice of the correct treatment more difficult. MATERIAL AND METHODS By reviewing the available literature of the last few years and taking into account considerations concerning the malalignment, an overview of the necessary diagnostics can be given. Radiographs and MRI are essential parts of the diagnostics after a traumatic patella dislocation. After re-dislocation, more extensive diagnostics are required to determine all pathological aspects of the malalignment. In this situation, a CT scan for measuring the torsion of the femur and the tibia as well as the TT-TG distance (tibial tubercle - trochlea groove), and the full weight-bearing long leg standing radiograph are part of the fundamental diagnostics. RESULTS The results that are presented in the literature provide some indications for a successful treatment. In consideration of the thorough analysis of the malalignment, the torsional correction of the femur and/or the tibia gains a new importance in the patellofemoral joint. The presented algorithm for diagnostics and treatment should make the decision for the best treatment easier. CONCLUSION The proposed algorithm for diagnostics and treatment is only partially founded on evidence-based results. Moreover, it takes into consideration reflections concerning the biomechanics of the patellofemoral joint and the realignment of this joint.

Co-Culture with Human Osteoblasts and Exposure to Extremely Low Frequency Pulsed Electromagnetic Fields Improve Osteogenic Differentiation of Human Adipose-Derived Mesenchymal Stem Cells

Human adipose-derived mesenchymal stem cells (Ad-MSCs) have been proposed as suitable option for cell-based therapies to support bone regeneration. In the bone environment, Ad-MSCs will receive stimuli from resident cells that may favor their osteogenic differentiation. There is recent evidence that this process can be further improved by extremely low frequency pulsed electromagnetic fields (ELF-PEMFs). Thus, the project aimed at (i) investigating whether co-culture conditions of human osteoblasts (OBs) and Ad-MSCs have an impact on their proliferation and osteogenic differentiation; (ii) whether this effect can be further improved by repetitive exposure to two specific ELF-PEMFs (16 and 26 Hz); (iii) and the effect of these ELF-PEMFs on human osteoclasts (OCs). Osteogenic differentiation was improved by co-culturing OBs and Ad-MSCs when compared to the individual mono-cultures. An OB to Ad-MSC ratio of 3:1 had best effects on total protein content, alkaline phosphatase (AP) activity, and matrix mineralization. Osteogenic differentiation was further improved by both ELF-PEMFs investigated. Interestingly, only repetitive exposure to 26 Hz ELF-PEMF increased Trap5B activity in OCs. Considering this result, a treatment with gradually increasing frequency might be of interest, as the lower frequency (16 Hz) could enhance bone formation, while the higher frequency (26 Hz) could enhance bone remodeling.

The effect of the arthroscopic augmentation of the subscapularis tendon on shoulder instability and range of motion: A biomechanical study

BACKGROUND Anterior shoulder dislocation is common. The treatment of recurrence with glenoid bone defect is still considered controversial. A new arthroscopic subscapularis augmentation has recently been described that functions to decrease the anterior translation of the humeral head. The purpose of the presented study was to examine the biomechanical effect on glenohumeral joint motion and stability. METHODS Eight fresh frozen cadaver shoulders were studied by use of a force guided industrial robot fitted with a six-component force-moment sensor to which the humerus was attached. The testing protocol includes measurement of glenohumeral translation in the anterior, anterior-inferior and inferior directions at 0°, 30° and 60° of glenohumeral abduction, respectively, with a passive humerus load of 30N in the testing direction. The maximum possible external rotation was measured at each abduction angle applying a moment of 1Nm. Each specimen was measured in a physiologic state, as well as after Bankart lesion with an anterior bone defect of 15-20% of the glenoid, after arthroscopic subscapularis augmentation and after Bankart repair. FINDINGS The arthroscopic subscapularis augmentation decreased the anterior and anterior-inferior translation. The Bankart repair did not restore the mechanical stability compared to the physiologic shoulder group. External rotation was decreased after arthroscopic subscapularis augmentation compared to the physiologic state, however, the limitation of external rotation was decreased at 60° abduction. INTERPRETATION The arthroscopic subscapularis augmentation investigated herein was observed to restore shoulder stability in an experimental model.

Septic arthritis of the knee: Presentation of a novel irrigation-suction system tested in a cadaver study

BackgroundThe established treatment for bacterial arthritis of the knee joint is arthroscopic surgery with irrigation and debridement. The aim of this article is to summarize the relevant data in treating bacterial arthritis of the knee joint, and based on these findings to present a novel irrigation suction system, tested in a cadaver study, as an additional tool in the postoperative treatment phase of arthroscopic surgery for knee joint infections.MethodThe novel automated irrigation-suction system presented here was compared to conventional continuous suction irrigation in a total of six knee joints. All knee joints were filled with 80 ml methylene blue stain and rinsed by two different methods. Fluid specimens were taken after ten and twenty minutes to be compared by photometric extinction measurement at a wave length of 500 nm.ResultsAfter ten minutes, the average extinction was e1C = 0.8 for the continuous suction irrigation and e1N = 0.4 for the novel irrigation-suction system. After twenty minutes, we recorded an average extinction of e2C = 0.3 for continuous suction irrigation and e2N = 0.001 for the novel irrigation-suction system. The students t- test revealed superior results after ten and twenty minutes of washing out the knee joints with a p < 0.001 for the novel irrigation-suction system.ConclusionA novel irrigation-suction system may be an effective tool for postoperative knee joint irrigation in arthroscopic therapy for bacterial arthritis of the knee. Further animal studies are needed to verify the effects in vivo.