Effects of plate contouring quality on the biomechanical performance of high tibial osteotomy fixation: A parametric finite element study

Locking plates have threaded holes, in which threaded-head screws are affixed. Hence, they do not need to be in intimate contact with underlying bone to provide fixation. There are, however, reports that a large distance between the plate and the bone might cause clinical complications such as delayed union or nonunion, screw pull out, and screw and plate breakage. Considering the diversity in the capabilities and costs of different plate customization techniques, the purpose of this study was to investigate the effect of the plate contouring quality on the biomechanical performance of high tibial osteotomy (HTO) fixation. A finite element model of proximal tibia was developed in Abaqus, using the QCT data of a cadaver. The model was then subjected to open-wedge HTO (correction angle 12°) with TomoFix plate fixation. The sagittal curvature of the plate was changed parametrically to provide certain levels of geometrical fit, and the biomechanical performance parameters of fixation were assessed. Results indicated 5%, 9% and 38% increase in the stiffness of the construct, and the von Mises stress in the plate and locking screw just above the osteotomy site, respectively, when the level of fit of plate changed from 0% (initial non-contoured initial shape) to 100% (fully adapted shape). The same change decreased the pressure at the lateral hinge of the osteotomy by 61%, and the mean of the tensile stress on the screw shaft by 12%. It was concluded that the level of fit has conflicting effects on the biomechanical parameters of the HTO fixation system, that is, the structural stiffness, the pressure at the lateral hinge, the stresses in the plate and screws, and the pull out resistance of the screws. In particular, for HTO patients with high quality bone, the optimal level of fit should provide a tradeoff between these parameters.

Growth Factors and Dental Implantology

Normal healing procedure of bone involves various sequential events to develop bone and bridge the bone -to- bone gap. When this healing occurs with a metal (titanium) fixture on one side, it is called as osseointegration. After extensive studies on this topic, it is found that this procedure occurs in presence of various biologic constituents that are spontaneously released at the site. Thus, to accelerate normal healing after implant placement and make results more predictable, it has been proposed to use these autologous factors in the osteotomy site. Since it is the beginning of a new revolution in dental implantology, right now it is essential to analyze all possible combinations of host conditions, bone quality and quantity and bio factors being used. This can definitely be a boon for the patients with compromised systemic or local conditions.

Does Transection of the Superficial MCL During HTO Result in Progressive Valgus Instability?

Background: During high tibial osteotomy (HTO), the superficial medial collateral ligament (sMCL) is cut or released at any degree to expose the osteotomy site and achieve the targeted alignment correction according to the surgeon’s preference. However, it is still unclear whether transection of sMCL increases valgus laxity. Purpose: We aimed to assess the outcomes and safety of sMCL transection, especially focusing on iatrogenic valgus instability. Study Design: Case series; Level of evidence, 4. Methods: Seventy-two patients (89 knees) who underwent medial open wedge HTO (MOWHTO) with transection of the sMCL between October 2013 and September 2018 were retrospectively investigated. Clinical evaluations, including the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Tegner and Lysholm scores, were performed preoperatively and at 2 years postoperatively. The radiographic parameters hip-knee-ankle (HKA) angle, joint line convergence angle on standing radiographs (standing JLCA), and weightbearing line (WBL) ratio were assessed preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. To evaluate valgus laxity, we assessed the valgus JLCA and medial joint opening (MJO) at the aforementioned time points using valgus stress radiographs. Results: All clinical results at the 2-year follow-up were significantly improved compared with those obtained at the preoperative assessment ( P < .001). The postoperative HKA angle significantly differed from the preoperative one, and no significant valgus progression was observed during follow-up (preoperative, 8.5°± 2.7°; 3 months, –3.5°± 2.0°; 6 months, –3.2°± 2.3°; 1 year, –3.1°± 2.3°; 2 years, –2.9°± 2.5°; P < .001) The mean WBL ratio was 62.5% ± 9.0% at 2 years postoperatively. The postoperative valgus JLCA at all follow-up points did not significantly change compared with the preoperative valgus JLCA (preoperative, –0.1°± 2.1°; 3 months, –0.2°± 2.4°; 6 months, –0.1°± 2.5°; 1 year, 0.1°± 2.5°; 2 years, 0.2°± 2.2°) The postoperative MJO at all follow-up points did not significantly change compared with the preoperative MJO (preoperative, 7.1 ± 1.7 mm; 3 months, 7.0 ± 1.7 mm; 6 months, 6.9 ± 1.9 mm; 1 year, 6.7 ± 1.8 mm; 2 years, 6.8 ± 1.8 mm). Conclusion: Transection of the sMCL during MOWHTO does not increase valgus laxity and could yield desirable clinical and radiographic results.

Frontal knee alignment influences the vertical orientation of the femoral neck in standing position

Aims The aim of this study was to determine the association between knee alignment and the vertical orientation of the femoral neck in relation to the floor. This could be clinically important because changes of femoral neck orientation might alter chondral joint contact zones and joint reaction forces, potentially inducing problems like pain in pre-existing chondral degeneration. Further, the femoral neck orientation influences the ischiofemoral space and a small ischiofemoral distance can lead to impingement. We hypothesized that a valgus knee alignment is associated with a more vertical orientation of the femoral neck in standing position, compared to a varus knee. We further hypothesized that realignment surgery around the knee alters the vertical orientation of the femoral neck. Methods Long-leg standing radiographs of patients undergoing realignment surgery around the knee were used. The hip-knee-ankle angle (HKA) and the vertical orientation of the femoral neck in relation to the floor were measured, prior to surgery and after osteotomy-site-union. Linear regression was performed to determine the influence of knee alignment on the vertical orientation of the femoral neck. Results The cohort included 147 patients who underwent knee realignment-surgery. The mean age was 51.5 years (SD 11). Overall, 106 patients underwent a valgisation-osteotomy, while 41 underwent varisation osteotomy. There was a significant association between the orientation of the knee and the coronal neck-orientation. In the varus group, the median orientation of the femoral neck was 46.5° (interquartile range (IQR) 49.7° to 50.0°), while in the valgus group, the orientation was 52.0° (IQR 46.5° to 56.7°; p < 0.001). Linear regression analysis revealed that HKA demonstrated a direct influence on the coronal neck-orientation ( β = 0.5 (95% confidence interval (CI) 0.2 to 0.7); p = 0.002). Linear regression also showed that realignment surgery was associated with a significant influence on the change in the coronal femoral neck orientation ( β = 5.6 (95% CI 1.5 to 9.8); p = 0.008). Conclusion Varus or valgus knee alignment is associated with either a more horizontal or a more vertical femoral neck orientation in standing position, respectively. Subsequently, osteotomies around the knee alter the vertical orientation of the femoral neck. These aspects are of importance when planning osteotomies around the knee in order to appreciate the effects on the adjacent hip joint. The concept may be of even more relevance in dysplastic hips. Cite this article: Bone Jt Open 2021;2(12):1057–1061.

Stability of Dental Implants and Thickness of Cortical Bone: Clinical Research and Future Perspectives. A Systematic Review

Dental surgery implantation has become increasingly important among procedures that aim to rehabilitate edentulous patients to restore esthetics and the mastication ability. The optimal stability of dental implants is correlated primarily to the quality and quantity of bone. This systematic literature review describes clinical research focusing on the correlation between cortical bone thickness and primary/secondary stability of dental fixtures. To predict successful outcome of prosthetic treatment, quantification of bone density at the osteotomy site is, in general, taken into account, with little attention being paid to assessment of the thickness of cortical bone. Nevertheless, local variations in bone structure (including cortical thickness) could explain differences in clinical practice with regard to implantation success, marginal bone resorption or anchorage loss. Current knowledge is preliminarily detailed, while tentatively identifying which inconclusive or unexplored aspects merit further investigation.

Calcaneal lengthening using ipsilateral fibula autograft in the treatment of symptomatic pes valgus in adolescents

Background Evans calcaneal lengthening osteotomy is used to treat symptomatic flexible flatfoot when conservative treatment fails. Grafts such as autologous iliac bone grafts, allografts, and xenografts are implanted at the osteotomy site to lengthen the lateral column of the hindfoot. This study aimed to present the outcomes of an autologous mid-fibula bone graft used for calcaneal lengthening in symptomatic pes valgus in adolescents. Methods We retrospectively examined 23 ft of 13 adolescents who underwent surgery between July 2014 and January 2018. The radiological and clinical outcomes (American Orthopaedic Foot and Ankle Society ankle-hindfoot scale scores) were assessed during a mean follow-up of 49.7 (range, 30.9–73.4) months. The mean distance of the lengthening site was measured to evaluate graft sinking or collapse. The Goldberg scoring system was used to determine the degree of union at the donor and recipient sites. Results The calcaneal pitch and the anteroposterior and lateral talo-first metatarsal (Meary) angles showed significant correction, from 14.4 to 19.6 (p < 0.001), and from 14.5 to 4.6 (p < 0.001) and 13.5 to 8.5 (p < 0.001), respectively. The mean distance of the lengthening site showed no significant change (p = 0.203), suggesting no graft sinking or postoperative collapse. The lateral distal tibial angle showed no significant difference (p = 0.398), suggesting no postoperative ankle valgus changes. Healing of the recipient and donor sites occurred in 23 and 21 ft, respectively. The American Orthopaedic Foot and Ankle Society ankle-hindfoot scores improved significantly, from 68.0 to 98.5 (p < 0.001). Conclusions Evans calcaneal lengthening using an ipsilateral mid-fibula bone autograft resulted in significant improvement in clinical and radiological outcomes without ankle valgus deformity. Hence, it could be a treatment option for lateral column calcaneal lengthening in adolescents.

Influence of the Use of a Collagen Membrane Placed on the Bone Window after Sinus Floor Augmentation—An Experimental Study in Rabbits

Background: We studied the influence on healing of a resorbable membrane covering the osteotomy site after maxillary sinus grafting, evaluated in different regions of the augmented area. Methods: Maxillary sinus augmentation was performed in 24 New Zealand rabbits. Osteotomy, 4 × 6 mm, were performed bilaterally. A collagenated cortico-cancellous porcine bone was used to fill the elevated region. A collagen membrane was randomly placed over the osteotomy site on one side (MG), and the other side was left uncovered (NMG). The animals were euthanized after 2, 4, and 8 weeks; and histomorphometric analysis was performed in eight different regions. Results: New bone percentages were similar in both groups. There were no statistically significant differences. In MG, the overall percentages were 15.6 ± 7.3%, 22.9 ± 6.1%, and 24.9 ± 12.0% after 2, 4, and 8 weeks, respectively. In NMG, the percentages were 11.2 ± 4.5%, 24.1 ± 5.7%, and 24.5 ± 15.7%, respectively. The proportions of new bone in the various regions after 8 weeks were 31 ± 8.9% and 29.9 ± 9.1% in the bone walls region, 25 ± 10.1% and 32.8 ± 9.1% in the submucosa region, 22.6 ± 21.6% and 10.9 ± 11.5 in the middle region, 17.3 ± 14% and 13.4 ± 9.8% in the close-to-window region, and 21.8 ± 11.6%, 19.1 ± 6.4% in the osteotomy region—for MG and NMG, respectively. Conclusions: In both groups the greatest amounts of bone formation occurred near to the pre-existing bone walls, followed by the sub-mucosa region. The smallest amounts were found in the close-to-window region, followed by the central region. The placement of a collagen membrane to cover the osteotomy site did not influence the amount of new bone formation after sinus grafting.

Clavicular osteotomy to assess subclavian vein injury during internal fixation of midshaft clavicle fractures

Midshaft clavicle fractures are commonly fixed with locking plates. The subclavian vein risks injury during this procedure and the consequences can be fatal. The purpose of this present study is to describe a clavicular osteotomy technique in order to equip orthopaedic surgeons with a means of rapidly accessing a subclavian vein injury. The osteotomy should only be performed following an urgent intraoperative vascular surgery assessment. There must be shared consensus from both orthopaedic and vascular surgery that direct repair of the subclavian vein is necessary, and further exposure is required. The results of the technique performed on thirteen embalmed cadaveric specimens are also included. The osteotomy was able to expose 3.16 cm (SD = 0.60) of the subclavian vein and both the fracture and osteotomy site of all clavicles (100%) were able to be reduced and fixed using a single pre-contoured fifteen-hole lateral plate intended for use on the contralateral shoulder. This surgical technique study confirms that in the rare circumstance that the osteotomy is utilized, adequate exposure of the subclavian vein is achieved.

A Comparative Analysis of the Piezoelectric Ultrasonic Appliance and Trephine Bur for Apical Location: An In Vitro Study

To compare and contrast the accuracy of piezoelectric ultrasonic insert (PUI) and trephine bur (TB) osteotomy site preparation techniques for apical location. (1) Material and methods: A total of 138 osteotomy site preparations were randomly distributed into one of two study groups. Group A: TB technique (n = 69) and B: PUI technique (n = 69). A preoperative cone-beam computed tomography scan and an intraoral scan were performed and uploaded to implant-planning software to plan the virtual osteotomy site preparations for apical location. Subsequently, the osteotomy site preparations were performed in the experimental models with both osteotomy site preparation techniques and a postoperative CBCT scan was performed and uploaded into the implant-planning software and matched with the virtually planned osteotomy site preparations to measure the deviation angle and horizontal deviation as captured at the coronal entry point and apical end-point between osteotomy site preparations using Student’s t-test statistical analysis. (2) Results: The paired t-test found statistically significant differences at the coronal entry-point deviations (p = 0.0104) and apical end-point deviations (p = 0.0104) between the TB and PUI study groups; however, no statistically significant differences were found in the angular deviations (p = 0.309) between the trephine bur and piezoelectric ultrasonic insert study groups. (3) Conclusions: The results showed that the TB is more accurate than the PUI for apical location.

In vivo Histological Examination of the Graft Site 3 Years after Open-wedge High Tibial Osteotomy with Nanohydroxyapatite Augmentation

Introduction:The open-wedge high tibial osteotomy (OWHTO) is a common technique for the treatment of medial compartmental osteoarthritis of the knee. There are many options to fill the osteotomy site gap. The autologous graft donor site morbidity can be avoided using heterologous bone grafts which represent a valid alternative. Case Presentation:This case report is about a 52-year-old male with knee osteoarthritis and varus deformity. Due to stiffness, swelling, and painful limitation during daily life activities, the patient underwent OWHTO. The osteotomy gap was filled with an equine cancellous bone wedge and nanohydroxyapatite (NHA) bone paste augmentation. After 3 years, the OWTHO was converted to total knee arthroplasty and a bone biopsy of the previous graft site was performed. The histological examination presented non-viable bone areas surrounded by viable bone without inflammatory cells, suggesting the presence of residual non-viable bone from the bone substitute graft. Conclusion:The in vivo histology of the graft site after 3 years has shown that heterologous bone is a safe and valid choice as a scaffold for bone regeneration. Augmentation with NHA bone paste achieved good osteoinduction without an inflammatory reaction and good integration of the bone substitute insert. Keywords: High tibial osteotomy, histology, heterograft.