Osteotomy Gap Research Articles

Sites of autogenous bone harvesting during orthognathic surgery

Bone grafting in orthognathic surgery is used for a variety of reasons, including promoting healing, buttressing large osteotomy gaps, and prevention of skeletal relapse post-operatively. With the ever-changing landscape of available grafting materials, it is possible to overlook a rich supply of autogenous bone which is readily available during orthognathic surgery. This purpose of this paper is to outline a comprehensive list of intra-oral autogenous bone harvest sites, all of which are readily available and accessible during routine orthognathic surgery. The aim of these techniques is to aid the surgeon in maximizing stability of the surgical construct while minimizing cost and morbidity.

Bridging the Gap. Is Augmentation Necessary During Opening-Wedge High Tibial Osteotomy?: Commentary on an article by Seong Chan Kim, MD, et al.: "Comparative Analysis of Serial Union Patterns After Opening-Wedge High Tibial Osteotomy with and without Bone-Void Fillers".

Commentary High tibial osteotomy of the knee is used to treat varus malalignment associated with unicompartmental osteoarthritis as well as instability and also can be combined with medial compartment cartilage-repair procedures. Various techniques exist; the lateral closing-wedge osteotomy is considered the traditional approach but is technically demanding and has been associated with major complications1. To minimize this complication profile and to improve on the technical challenges, the opening-wedge high tibial osteotomy was developed. However, that procedure presents different challenges specifically related to bone union of the opening wedge and stabilization of the gap during healing. In a study by Martin et al.1, 323 consecutive opening-wedge high tibial osteotomies were evaluated to provide a comprehensive description of adverse event rates, categorized by severity, and their effect on patient-reported outcomes. Overall, the authors noted that the rate of severe adverse events was 7%, with the most common being nonunion (3.2%). Furthermore, the most common event requiring nonoperative treatment was delayed union (12%). With this issue of nonunion and delayed union in mind, Kim et al. sought to determine if bone-void fillers were necessary to achieve bone union of the opening gap following opening-wedge high tibial osteotomy. The authors retrospectively evaluated 97 patients who had undergone primary opening-wedge high tibial osteotomy with an opening gap between 8 and 15 mm. The cases were divided into 3 groups, with either hydroxyapatite chip bone graft, allogeneic chip bone graft, or no bone graft being utilized at the gap site. Based on the radiographic evaluations performed, it was noted that the group that had received no bone graft had slow bone union progression up to 6 weeks but demonstrated more prominent progression of gap filling compared with the other groups at 6 months postoperatively. At the 1-year postoperative time point, a similar degree of union was observed among all groups. Furthermore, the bone union pattern did not correlate with the degree of correction after the 3-month postoperative time point in all groups. The findings of this study call into question the need for a bone-void filler when performing an opening-wedge high tibial osteotomy. As the authors note, their findings confirm the results of a systematic review by Slevin et al.2 that evaluated the outcomes and complications after opening-wedge high tibial osteotomy. In that review of 22 articles reporting the results of 1,421 opening-wedge high tibial osteotomies, the use of synthetic bone substitutes could not be recommended as there were no definitive advantages with any bone-void filler in terms of union rates and loss of correction. While synthetic bone substitutes may not improve union rates after opening-wedge high tibial osteotomy, autograft bone-filled osteotomies might be considered a superior alternative. Lash and colleagues3, in a systematic review, noted the lowest rates of delayed union/nonunion following opening-wedge osteotomies around the knee filled with autograft bone. However, 2 more recent studies have questioned the superiority of autograft augmentation during opening-wedge high tibial osteotomy4,5. In a systematic review and meta-analysis evaluating whether bone-grafting is necessary for opening-wedge high tibial osteotomy, Ren et al.4 reported that the overall estimate demonstrated no significant difference in the loss of correction or complications between the groups treated with either autograft, allograft, or no fill. Interestingly, the no-fill group had statistically better Knee Society scores. Those findings were confirmed in the study by Fucentese et al.5, who evaluated 15 patients undergoing opening-wedge high tibial osteotomy with iliac crest autograft augmentation and 25 patients undergoing opening-wedge high tibial osteotomy without bone-void filler. While the iliac crest augmentation significantly increased healing of the osteotomy gap, no functional advantage was found in comparison with the group without a bone-void filler at 3 or 12 months postoperatively. Based on their findings, the authors could not recommend the routine use of iliac crest autograft during opening-wedge high tibial osteotomy. The findings of the study by Kim et al. support and confirm the current literature that bone union-related issues and clinical outcomes after opening-wedge high tibial osteotomy may not be impacted by the material utilized to fill the wedge. Instead, the problems involving delayed union and nonunion are more likely to be related to a combination of multiple factors, including wedge size, plate type, fracture of the lateral hinge, smoking, body mass index, and the postoperative weight-bearing protocol1. Future research will need to control for these multiple factors and their complex interplay in order to identify the underlying issues of concern.

Accuracy of Virtual Surgical Planning with Mandible-first Surgery and Factors that may Affect It

Planning bimaxillary orthognathic surgery has become much easier and the workflow more streamlined with the advent of virtual surgical planning (VSP). Among its advantages, VSP allows for easy transition between performing maxillary or mandibular surgery first, as it eliminates the cumbersome process of reverse model surgery. In this experience of performing mandible surgery first, it was observed that the osteotomy gaps at the piriform and zygoma appeared to be different than what was predicted on the VSP. The present study was initiated to compare the planned movements to the actual achieved surgical position of the maxilla after correction of dentoskeletal deformity. The goal of the study was to evaluate the accuracy of a maxillary surgery-first sequence and a mandibular surgery-first sequence. Additionally, the researchers sought to determine if any surgical interventions could mitigate the under-advancement noted in observations.The authors implemented a retrospective audit of 61 patients who underwent bimaxillary orthognathic surgery from January 2017 to September 2020. Exclusion criteria included previous cleft lip/palate surgery, previous orthognathic surgery, lack of a post-surgical CBCT, non-sagittal split osteotomies of the mandible, or if there was greater than 3mm vertical deviation in planned and achieved surgical position of the central incisor based on intraoperative incisor show. Patients were divided into 2 groups based on the surgical sequencing used; 28 patients had maxillary surgery performed first and 33 underwent mandibular-first surgery. Pre-surgical and post-surgical CBCT scans were analyzed by 3D Systems engineers, with overlays made using the predicted osteotomies and the postoperative CBCT scans. A pre-determined set of skeletal landmarks were measured on the virtual surgical plan and the actual postoperative images, and the difference between the planned and actual position was calculated for each reference point for each patient. The absolute value of each difference was then calculated, and a series of 2 sample T-tests was performed to compare the average absolute difference between planned and actual position between groups.The absolute values of the linear (mm) and angular (°) measurement differences between planned and postoperative results demonstrate statistically significant differences in accuracy between the 2 groups, with greater deviation in the mandible-first group. The maxillary central incisors were under advanced in the anterior-posterior (AP) direction in both groups. Additionally, a significant difference in reference points ISU1 (AP) and A Point (AP) was noted between the groups, indicating that greater inaccuracy lies within the mandibular-first group. However, the majority of data points show deviation from the surgical plan less than or equal to 2mm and 4 degrees, meeting previously described success criteria.1,2To further evaluate the larger maxillary under advancement in the mandible-first surgery cohort, the researchers sub-divided the mandible-first surgery group to evaluate factors that may explain the difference, 1 factor being the type of fixation used for sagittal split segments, rigid or non-rigid. When comparing the average linear measurements, the non-rigid fixation group showed less accuracy when compared to the rigid fixation group, and this was statistically significant (P-value: .007).In conclusion, the findings of the present study demonstrate that virtual surgical planning can be less accurate in predicting the maxillary incisor position when mandibular surgery is performed first, but this inaccuracy is within the acceptable range and can be mitigated by more rigid fixation of the mandible.

Complications of open wedge high tibial osteotomy. Analysis of the causes of complications and ways to eliminate them

Objective – to study the complications of open wedge high tibial osteotomy (OWHTO) in patients who underwent this surgery in the V.A. Nasonova Research Institute of Rheumatology.Materials and methods. The study included 43 patients (46 knee joints) with primary and secondary OA of the knee of I–III stages, who underwent OWHTO in the period from 2005 to 2019. The operation was performed according to the standard technique using short spacer plates (Puddu I (5 times) and II generation (24 times), Osteomed (17 times)) and bone grafting. The identified OWHTO specific complications were divided into those related to the osteotomy, fixation, and bone grafting. To assess the result, we studied the change in pain according to the Visual Analog Scale (VAS), as well as the functional and objective state of the knee according to the Knee Society Score (KSS) before surgery, after 3 months and 1 year after surgery.Results. In 15 (32.7%) cases have been diagnosed 26 complications. Of these, 21 (81.0%) were associated with fixation, 2 (7.7%) with the osteotomy 2 (7.7%) with bone grafting of the osteotomy gap, and 1 (3.6%) a local complication. Patients without complications had a statistically significantly better decrease in pain intensity according to VAS (p=0.0005), and an improvement in the total score of KSS (p=0.0023) one year after surgery. Outcomes were also better in patients without complications: 96.7% excellent and good results versus 60.0% in patients with complications one year after OWHTO. In total, we had 43.5% excellent, 41.3% good and 15.2% satisfactory results one year after surgery.Conclusions. OWHTO is a highly effective method of surgical treatment of the osteoarthritis of the knee, which allows to obtain an excellent and good treatment result in 84.8% of cases one year after surgery. Performing OWHTO with fixing the height of the osteotomy gap using short spacer plates and bone grafting in 32.7% of cases is associated with the development of complications. To improve the results of OWHTO, it is necessary to improve the surgical technique and fixator.

Supplemental medial small fragment fixation adds stability to distal femur fixation: A biomechanical study

Introduction: Bridge plating of distal femur fractures with lateral locking plates is susceptible to varus collapse, fixation failure, and nonunion. While medial and lateral dual plating has been described in clinical series, the biomechanical effects of dual plating of distal femur fractures have yet to be clearly defined. The purpose of this study was to compare dual plating to lateral locked bridge plating alone in a cadaveric distal femur gap osteotomy model.Materials and Methods: Gap osteotomies were created in eight matched pairs of cadaveric female distal femurs (average age: 64 yrs (standard deviation ± 4.4 yrs); age range: 57–68 yrs;) to simulate comminuted extraarticular distal femur fractures (AO/OTA 33A). Eight femurs underwent fixation with lateral locked plates alone and were matched with eight femurs treated with dual plating: lateral locked plates with supplemental medial small fragment non-locking fixation. Mechanical testing was performed on an ElectroPuls E10000 materials testing system using a 10 kN/100 Nm biaxial load cell. Specimens were subject to 25,000 cycles of cyclic loading from 100-1000 N at 2 Hz.Results: Two (2/8) specimens in the lateral only group failed catastrophically prior to completion of testing. All dual plated specimens survived the testing regimen. Dual plated specimens demonstrated significantly less coronal plane displacement (median 0.2 degrees, interquartile range [IQR], 0.0–0.5 degrees) compared to 2.0 degrees (IQR 1.9-3.3, p = 0.02) in the lateral plate only group. Dual plated specimens demonstrated greater bending stiffness compared to the lateral plated group (median 29.0 kN/degree, IQR 1.5–68.2 kN/degree vs median 0.50 kN/degree, IQR 0.23–2.28 kN/degree, p = 0.03).Conclusion: Contemporary fixation methods with a distal femur fractures are susceptible to mechanical failure and nonunion with lateral plates alone. Dual plate fixation in a cadaveric model of distal femur fractures underwent significantly less displacement under simulated weight bearing conditions and demonstrated greater stiffness than lateral plating alone. Given the significant clinical failure rates of lateral bridge plating in distal femur fractures, supplemental fixation should be considered, and dual plating of distal femurs augments mechanical stability in a clinically relevant magnitude.

Preliminary Clinical and Radiographic Evaluation of a Novel Resorbable Implant of Polylactic Acid (PLA) for Tibial Tuberosity Advancement (TTA) by Modified Maquet Technique (MMT).

Simple SummaryThe metallic implants carry many problems as infections, bone resorption, pain at the site, etc. Removing these metallic implants is an expensive procedure, and it entails risks. Due to the costs, the most common in veterinary medicine is to remove metallic implants only when a problem occurs. The rupture of the cranial cruciate ligament (RCrCL) is the most common orthopedic pathology in dogs and the most frequent cause of arthrosis, pain, and limp on the knee joint. Those are the reasons that encouraged us to develop a new type of biodegradable implant comprised of polylactic acid (PLA). This is a non-toxic material that can be eliminated by natural metabolic pathways and use the PLA implant in tibial tuberosity advancement (TTA), which is a technique for the resolution of RCrCL in dogs. In our study, PLA implants for TTA provide good functional results, presenting an acceptable number of complications. The implants show a faster ossification than metallic implants, which was not affected by age or by body weight. The PLA implants have a clinical recovery time similar to metallic implants.Our objectives were to determine whether PLA implants can be used in TTA with successful results; secondly, to observe whether they provide a faster bone healing; finally, to determine whether weight or age influences bone healing scores. PLA cages were created with a 3D printer. TTA by MMT with PLA implants was performed in 24 patients. Follow-ups were carried out pre-surgical, at 1, 2, and 5 months and consisted of a radiographic study and a lameness assessment. A comparison was performed in terms of weight and age. Patients data, time between follow-up examinations, healing score, and lameness score were compared between patients using commercial software for statistically significant differences p < 0.05. Eighteen dogs finished the study. The ossification degrees presented statistically significant differences between each other. PLA implants maintained the advancement in 100% of cases. Comparing weight and age did not present any statistically significant differences between groups. Lameness presented statistically significant differences between follow-up examinations. Complications were observed in 20.8%. PLA implants for TTA provide good functional results, presenting an acceptable rate of complications. They provide a faster bone healing of the osteotomy gap, which was not affected by age or body weight, and have a clinical recovery time similar to metallic implants.

Treatment of cranial cruciate ligament injuries in dogs using a combination of tibial tuberosity advancement procedure and autologous mesenchymal stem cells/multipotent mesenchymal stromal cells - A pilot study.

In the present pilot study, we evaluated different supplemental therapies using autologous multipotent mesenchymal stromal cells (MMSCs) for the treatment of cranial cruciate ligament defects in dogs. We used tibial tuberosity advancement (TTA) and augmented it by supportive therapy with MMSCs in three patient groups. In the first patient group, the dogs were injected with MMSCs directly into the treated stifle one month after surgery. In the second group, MMSCs were delivered in a silk fibroin scaffold which was placed in the osteotomy gap during surgery. In the third group, MMSCs were first mixed with bone tissue and blood from the patient and delivered into the osteotomy gap during surgery. In the control group, patients underwent the TTA procedure but did not receive MMSC treatment. In the group of patients who received cells in the silk fibroin scaffold during surgery, the osteotomy gap did not heal, presumably due to the low absorption of silk fibroin. Patients who received MMSCs mixed with bone tissue and blood during surgery into the osteotomy gap recovered clinically faster and had better healing of the osteotomy gap than dogs from the other two treated groups and from the control group, as assessed by clinical examination and quantification of radiographs. In conclusion, dogs that received stem cells directly into the osteotomy gap (Group 3) recovered faster compared to dogs from Groups 1 (MMSCs injected into the joint one month after surgery), 2 (cells implanted into the osteotomy gap in a silk fibroin scaffold), and the control group that did not receive additional MMSCs treatment.

The application of an allogeneic bone screw for osteosynthesis in hand and foot surgery: a case series

IntroductionThe allogeneic bone screw transplant is a new osteosynthesis device making the use of foreign fixation material obsolete for various kinds of indications. Moreover, it is integrated into the recipient bone by natural bone remodeling without harming the surrounding tissue. The aim of this study was to determine the efficacy and safety of the transplant for osteotomy and arthrodesis in hand and foot surgery and to evaluate the clinical importance of the device.Materials and methodsA single-surgeon case series of 32 patients who had undergone hand or foot surgery with the application of an allogeneic bone screw with an average follow-up time of 1 year is reported. Clinical data were reviewed to evaluate the pain levels and satisfaction of the patients and the frequency and type of complications occurring during the healing process. Routine radiography and computed tomography were reviewed to determine the fusion rate, the ingrowth behavior of the transplant and the possible occurrence of transplant failure.ResultsHigh patient satisfaction was paired with low postoperative pain levels and a low complication rate. 97% of the patients were free of pain at the timepoint of the second follow-up examination, the mean time of recovery of full mobility was 50.1 ± 26.1 days after surgery. Wound healing disturbance occurred only in two cases. Bony consolidation of the osteotomy or arthrodesis gap as well as osseointegration of the transplant was seen in all cases. No transplant failure or transplant loosening occurred.ConclusionsThe application of the allogeneic bone screw resulted in a 100% fusion rate while the patient burden was low. The transplant is safe and suited for various kinds of osteosynthesis in hand and foot surgery.

Differences in impact on adjacent compartments in medial unicompartmental knee arthroplasty versus high tibial osteotomy with identical valgus alignment

BackgroundIt is unclear why medial unicompartmental knee arthroplasty (UKA) with postoperative valgus alignment causes adjacent compartment osteoarthritis more often than high tibial osteotomy (HTO) for moderate medial osteoarthritis of the knee with varus deformity. This study used a computer simulation to evaluate differences in knee conditions between UKA and HTO with identical valgus alignment. MethodsDynamic musculoskeletal computer analyses of gait were performed. The hip–knee–ankle angle in fixed-bearing UKA was changed from neutral to 7° valgus by changing the tibial insert thickness. The hip–knee–ankle angle in open-wedge HTO was also changed from neutral to 7° valgus by opening the osteotomy gap. ResultsThe lateral tibiofemoral contact forces in HTO were larger than those in UKA until moderate valgus alignments. However, the impact of valgus alignment on increasing lateral forces was more pronounced in UKA, which ultimately demonstrated a larger lateral force than HTO. Valgus alignment in UKA caused progressive ligamentous tightness, including that of the anterior cruciate ligament, resulting in compression of the lateral tibiofemoral compartment. Simultaneously, patellofemoral shear forces were slightly increased and excessive external femoral rotation against the tibia occurred due to the flat medial tibial insert surface and decreased lateral compartment congruency. By contrast, only lateral femoral slide against the tibia occurred in excessively valgus-aligned HTO. ConclusionsIn contrast to extra-articular correction in HTO, which results from opening the osteotomy gap, intra-articular valgus correction in UKA with thicker tibial inserts caused progressive ligamentous tightness and kinematic abnormalities, resulting in early osteoarthritis progression into adjacent compartments.

The degree of correction in open-wedge high tibial osteotomy compromises bone healing: A consecutive review of 101 cases

BackgroundThe bone healing in open-wedge high tibial osteotomy (OWHTO) proceeds gradually by a filling of the osteotomy gap. This can comprise several risk factors. MethodsA retrospective study analysed the clinical and radiological course of 101 consecutive OWHTOs in 96 patients. The following risk factors were considered: age, body mass index, tobacco consumption, amount of tobacco consumption, severity of comorbidities, infection of the surgical area, occurrence of a lateral hinge fracture and the degree of correction. The bone healing was evaluated by using the modified Radiographic Union Score for Tibial fractures (RUST). ResultsA disturbance in bone healing was observed in 16 of the 101 osteotomies. Binary logistic regression analysis showed a correlation between the angle of the opening wedge and the development of a disturbance in bone healing (P = 0.002). The odds ratio indicated an increase in the risk of a disturbance in bone healing of 56% with each additional degree of correction. For the risk factor ‘age’ a statistical trend was recognizable (P = 0.077) with the risk of a disturbance in bone healing in higher age. ConclusionLateral hinge fractures seem not to have a detrimental effect on the filling of the osteotomy gap. An increase in the opening wedge bears the risk of a disturbance in bone healing.

Bone healing on serial plain radiographs occurs slowly but adequately after medial opening wedge high tibial osteotomy without bone graft.

The purpose of this study was to prospectively investigate osteotomy gap filling rates on serial plain radiographs, and to evaluate whether alignment correction is maintained after medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate without bone graft. Between March 2014 and June 2017, MOWHTO was performed without bone graft regardless of gap size. Radiographs were taken preoperatively, postoperatively, at 1, 3, 6, 12, 18, and 24months after surgery. Radiographic examinations included a weight bearing long-standing anteroposterior (AP) view of the whole lower extremity, as well as, the AP, lateral, and both oblique views of the knee. Bone healing was measured on the medial oblique view of the knee. The postoperative alignment correction and its maintenance were assessed using the three radiologic parameters of the weight-bearing line (WBL) ratio, the hip-knee-ankle angle (HKAA), and the medial proximal tibial angle (MPTA) on the weight-bearing long-standing AP view of the lower extremity. Fifty-two consecutive patients underwent MOWHTO, but three patients failed to follow-up for more than 24months. A total of 49 patients were assessed in this study. The median opening gap height was 10.0mm (IQR, 8.0-12.0; range, 7-20). On immediate post-operative radiographs, the mean gap filling was 31.4 ± 3.6%. After 1, 3, 6, 12, 18, and 24months, the mean gap filling rates increased to 38.7 ± 4.4%, 51.4 ± 6.6%, 66.5 ± 5.1%, 84.8 ± 7.0%, 92.4 ± 5.6%, and 97.8 ± 2.3%, respectively. Statistical differences were observed between all the follow-up evaluations (P < 0.001). Statistical differences in the WBL ratio, HKAA, and MPTA were observed between preoperatively and 1month after surgery (P < 0.001). The mean PTSA increased significantly from preoperatively to postoperatively (P < 0.001). However, no statistical differences were found between the post-operative follow-up radiographs performed for these four values. MOWHTO using a locking plate without bone graft achieved at least 90% bone healing and had no loss in correction at 2 years postoperatively. III.

Tibial Slope Can Be Maintained During Medial Opening-Wedge Proximal Tibial Osteotomy With Sagittally Oriented Hinge, Posterior Plate Position, and Knee Hyperextension: A Cadaveric Study

The purpose of this study is (1) to determine if, when optimizing modern techniques, medial opening-wedge osteotomies can effectively maintain tibial slope and (2) to determine how different magnitude coronal plane corrections affect tibial slope. Proximal tibial osteotomies (PTOs) were performed on 10 fresh-frozen cadaveric knees leaving a consistent lateral hinge, using either a 5-mm or a 10-mm trapezoidal wedged osteotomy plate. Techniques including posterior plate placement; a trapezoidal, sloped plate; and knee hyperextension were used during plate fixation to help close the anterior osteotomy gap. Medial coronal proximal tibia angle and posterior tibial slope were measured preosteotomy, after a 5-mm implant, and after a 10-mm implant using true anteroposterior and lateral fluoroscopic images. Three independent observers performed all radiographic measurements, and intraclass correlation coefficients were calculated. The 5-mm and 10-mm osteotomy plates increased the coronal medial proximal tibia angle by a mean of 3.4° (range, 3.0°-3.7°) and 7.3° (range, 6.7°-7.7°), respectively. The 5-mm and 10-mm trapezoidal wedged osteotomy plates decreased the posterior tibial slope by a mean of 0.9° (range, 0.5°-1.2°) and 0.3° (range, 0°-0.6°), respectively. Intraobserver reliability was found to be high for both the coronal medial proximal tibia angle (intraclass correlation coefficient [ICC]= 0.897 [0.821-0.946]) and the tibial slope measurements (ICC= 0.761 [0.672-0.826]). When optimizing the medial opening-wedge proximal tibial osteotomy, including utilization of a sagittally oriented hinge, placement of a trapezoidal plate posteriorly, and fixation with knee hyperextension, posterior tibial slope can be maintained regardless of the degree of coronal correction. Tibial slope has a significant effect on cruciate ligament stress and a better understanding of coronal plane correction, and its effect on tibial slope is critical when performing proximal tibia osteotomies.

Tips and tricks to achieve osteotomy healing and prevent refracture after ulnar shortening osteotomy

BackgroundParallel osteotomy is essential for favorable osteotomy reduction and healing and technically challenging during diaphyseal ulnar shortening osteotomy (USO). This study aimed to evaluate the advantages of guided osteotomy for parallel osteotomy and reduction osteotomies, healing over freehand osteotomy. It also aimed to identify surgical factors affecting healing after diaphyseal USO.MethodsBetween June 2005 and March 2016, 136 wrists that had undergone diaphyseal USO for ulnar impaction syndrome (UIS) were evaluated. The wrists were divided into two groups according to the osteotomy technique (group 1: freehand osteotomy, 74 wrists; group 2: guided osteotomy, 62 wrists). The osteotomy reduction gap and time to osteotomy healing (union and consolidation) were compared between the groups. A multiple regression test was performed to identify the surgical factors affecting healing. The cut-off length of the reduction gap to achieve osteotomy union on time and the cut-off period to decide the failure of complete consolidation were statistically calculated.ResultsThe baseline characteristics did not differ between the two groups. The osteotomy reduction gap and time to osteotomy union, and complete consolidation were shorter in group 2 than in group 1 (p = 0.002, < 0.001, 0.002). The osteotomy reduction gap was a critical surgical factor affecting both time to osteotomy union and complete consolidation (p < 0.001, < 0.001). The use of a dynamic compression plate affected only the time to complete consolidation (p < 0.001). The cut-off length of the osteotomy reduction gap to achieve osteotomy union on time was 0.85 mm. The cut-off period to decide the failure of complete consolidation was 23.5 months after osteotomy.ConclusionsThe minimal osteotomy reduction gap was the most important for timely osteotomy healing in the healthy ulna, and guided osteotomy was beneficial for reducing the osteotomy reduction gap.

Analysis for different functional results of TMJ ankylosis management by comparing ramus-condyle unit reconstruction using vertical ramus osteotomy and interpositional gap arthroplasty

The objective of the present study was to analyze the functional results of temporomandibular joint (TMJ) range; that is, trismus index, lateral excursion, protrusion, retrusion, occlusion, masticatory efficiency), reestablishment of the anatomic relationship of the TMJ, aesthetics to improve quality of life, and complications in terms of ramus shortening on the affected side, deviation, facial asymmetry, neurologic deficits, and reankylosis. Sixteen patients with unilateral bony ankylosis were included and randomly divided into 2 groups with 8 patients in each group. Group I was treated with interpositional gap arthroplasty followed by reconstruction of the ramus-condyle unit using vertical ramus osteotomy. Group II was treated with interpositional gap arthroplasty. In both groups, a pedicled flap made up of fascia, temporalis muscle, and pericranium was used as an interpositional material. The functional range of the mandible was analyzed pre- and postoperatively. Group I improved significantly more than group II in terms of TMJ range; that is, trismus index, lateral excursion, protrusion, retrusion, reestablishment of the normal anatomic relationship of the TMJ, aesthetics, and masticatory efficiency. The reestablishment of anatomic relationship showed better result in mastication significantly. No reankylosis was reported in any of the groups. The functional results and aesthetics with TMJ reconstruction are significantly better.

Undercorrection: the undesired effect of compression on the osteotomy gap of the medial opening wedge high tibial osteotomy and its clinical significance.

Undercorrection is a common problem in opening wedge high tibial osteotomy (OWHTO). We investigated the compression effect of cortex screw on the osteotomy gap and its clinical significance. A standard OWHTO using the TomoFix plate was conducted on 20 bone models in two groups to get a 10-mm medial osteotomy gap. A cortex screw was used temporarily in a neutral (at the center) and an eccentric position (near the inclined plane) of the dynamic hole in group 1 and group 2, respectively. The mean of undercorrection observed in the two groups was compared using an independent t test. Also, the effect of compression on the gap between the plate and medial tibial cortex, and the osteotomy gap was evaluated using a Sine rule. Besides, the mean undercorrection observed was assessed for clinical significance based on the effect on the weight-bearing axis (WBA) using a Cosine Rule. The mean undercorrection was 1.3 ± 0.6mm and 2.6 ± 0.6mm in group 1 and group 2, respectively. A significantly greater undercorrection was observed in group 2 (p < 0.001). The correction loss in group 2 has resulted from combinations of the sliding effect of the dynamic hole and oblique compression effect over the gap between the plate and medial tibial cortex whereas in group 1 it has only resulted from the oblique compression effect. The observed undercorrection in group 2 has resulted in clinically significant WBA shift (10%) over the width of the tibial plateau. In OWHTO, compression is important for the stability and healing of osteotomy, but it can also cause loss of correction. In patients requiring large correction, the surgeon should control the amount of compression required and consider making extra osteotomy gap to avoid undercorrection. Furthermore, the placement of cortex screws in neutral is essential to lower the risk of undercorrection.

Biomechanical evaluation of a modified proximal humeral locking plate application for distal extra-articular diaphyseal humeral fractures.

The extra-articular distal humerus locking plate (EADHP) is widely used for distal extra-articular diaphyseal humeral fracture fixation. However, it occasionally causes skin prominence and discomfort. The upside-down use of a proximal humerus internal locking system (PHILOS) plate is suggested as an alternative option, but it lacks biomechanical evidence. The purpose of this study was to compare the biomechanical performance between two different fixation methods: themodified use of the PHILOS plate on the anterior cortex versus conventional use of an EADHP on the posterior cortex. Twelve pairs of fresh-frozen cadaveric humeri were used and 7 mm gap osteotomy was performed at 50 mm proximal to the lateral epicondyle to simulate an AO/OTA 12-C1.3 fracture type. Single load to failure was measured after five stiffness tests of the plate-bone constructs in anterior/posterior bending, internal/external torsion, and axial compression. There were no significant differences in metrics between the two groups, except for the load to failure in posterior bending, which was significantly higher for PHILOS (1589.3 ± 234.5) compared to EADHP (1430.1 ± 188.6), p < .023. In conclusion, the modified use of the PHILOS plate showed comparable biomechanical performance compared to the conventional EADHP. The new fixation method offers potential clinical advantages, considering the patient's position and surgical approach at the time of surgery as well as postoperative soft tissue irritation. Therefore, this could be an option for distal humeral extra-articular diaphyseal fracture fixation when the use of EADHP is not suitable or preferred.

Variable fixation promotes callus formation: an experimental study on transverse tibial osteotomies stabilized with locking plates

BackgroundA new locking screw technology, named variable fixation, has been developed aiming at promoting bone callus formation providing initial rigid fixation followed by progressive fracture gap dynamisation. In this study, we compared bone callus formation in osteotomies stabilized with standard locking fixation against that of osteotomies stabilized with variable fixation in an established tibia ovine model.MethodsA 3 mm tibial transverse osteotomy gap was stabilized in three groups of six female sheep each with a locking plate and either 1) standard fixation in both segments (group LS) or 2) variable fixation in the proximal and standard fixation in the distal bone segment (group VFLS3) or 3) variable fixation in both segments (group VFLS6). The implantation site and fracture healing were compared between groups by means of radiologic, micro tomographic, biomechanical, and histological investigations.ResultsCompared to LS callus, VFLS3 callus was 40% larger and about 3% denser, while VFLS6 callus was 93% larger and its density about 7.2% lower. VFLS3 showed 65% and VFLS6 163% larger amount of callus at the cis-cortex. There wasn’t a significant difference in the amount of callus at the cis and trans-cortex in groups featuring variable fixation only. Investigated biomechanical variables were not significantly different among groups and histology showed comparable good healing in all groups. Tissues adjacent to the implants did not show any alteration of the normal structure in all groups.ConclusionsVariable fixation promoted the formation of a larger amount of bone callus, equally distributed at the cis and trans cortices. The histological and biomechanical properties of the variable fixation callus were equivalent to those of the standard fixation callus. The magnitude of variable fixation had a biological effect on the formation of bone callus. At the implantation site, the usage of variable fixation did not raise additional concerns with respect to standard fixation. The formation of a larger amount of mature callus suggests that fractures treated with variable fixation might have a higher probability to bridge the fracture gap. The conditions where its usage can be most beneficial for patients needs to be clinically defined.

Risk factors for neurological complications in severe and rigid spinal deformity correction of 177 cases

BackgroundDifficult procedures of severe rigid spinal deformity increase the risk of intraoperative neurological injury. Here, we aimed to investigate the preoperative and intraoperative risk factors for postoperative neurological complications when treating severe rigid spinal deformity.MethodsOne hundred seventy-seven consecutive patients who underwent severe rigid spinal deformity correction were assigned into 2 groups: the neurological complication (NC, 22 cases) group or non-NC group (155 cases). The baseline demographics, preoperative spinal cord functional classification, radiographic parameters (curve type, curve magnitude, and coronal/sagittal/total deformity angular ratio [C/S/T-DAR]), and surgical variables (correction rate, osteotomy type, location, shortening distance of the osteotomy gap, and anterior column support) were analyzed to determine the risk factors for postoperative neurological complications.ResultsFifty-eight patients (32.8%) had intraoperative evoked potentials (EP) events. Twenty-two cases (12.4%) developed postoperative neurological complications. Age and etiology were closely related to postoperative neurological complications. The spinal cord functional classification analysis showed a lower proportion of type A, and a higher proportion of type C in the NC group. The NC group had a larger preoperative scoliosis angle, kyphosis angle, S-DAR, T-DAR, and kyphosis correction rate than the non-NC group. The results showed that the NC group tended to undergo high-grade osteotomy. No significant differences were observed in shortening distance or anterior column support of the osteotomy area between the two groups.ConclusionsPostoperative neurological complications were closely related to preoperative age, etiology, severity of deformity, angulation rate, spinal cord function classification, intraoperative osteotomy site, osteotomy type, and kyphosis correction rate. Identification of these risk factors and relative development of surgical techniques will help to minimize neural injuries and manage postoperative neurological complications.

Biomechanical evaluation of the docking nail concept in periprosthetic fracture fixation around a stemmed total knee arthroplasty

Intramedullary femoral nails provide an ideal mechanical axis for periprosthetic fracture fixation. Slotted nails allow a connection to a total knee arthroplasty (TKA) stem. This study aims to compare implant and construct stiffness, interfragmentary movement and cycles to failure between an antegrade slotted femoral nail construct docked to a TKA stem and a distal femoral locking plate in a human periprosthetic femoral fracture model.In eight pairs of fresh-frozen human femora with stalked TKA, a 10 mm transverse osteotomy gap was set simulating a Rorabeck type II, Su type I fracture. The femora were pairwise instrumented with either an antegrade slotted nail coupled to the prosthesis stem, or a locking plate. Cyclic testing with a progressively increasing physiologic loading profile was performed at 2 Hz until catastrophic construct failure. Relative movement at the osteotomy site was monitored by means of optical motion tracking. In addition, four-point bending implant stiffness, torsional implant stiffness and frictional fit of the stem-nail connection were investigated via separate non-destructive tests.Intramedullary nails exhibited significantly higher four-point bending and significantly lower torsional implant stiffness than plates, P < 0.01. Increasing difference between nail and stem diameters decreased frictional fit at the stem-nail junction. Nail constructs provided significantly higher initial axial bending stiffness and cycles to failure (200 ± 83 N/mm; 16'871 ± 5'227) compared to plate constructs (93 ± 35 N/mm; 7'562 ± 1'064), P = 0.01. Relative axial translation at osteotomy level after 2'500 cycles was significantly smaller for nail fixation (0.14 ± 0.11 mm) compared with plate fixation (0.99 ± 0.20 mm), P < 0.01.From a biomechanical perspective, the docking nail concept offers higher initial and secondary stability under dynamic axial loading versus plating in TKA periprosthetic fracture fixation.

Treatment of aseptic nonunion after medial opening-wedge high tibial osteotomy.

Nonunion after medial opening-wedge high tibial osteotomy (OWHTO) is a rare but serious complication with very limited data regarding its treatment. The aim of this study was to analyze the healing rate after operative treatment of nonunion after OWHTO. We performed a single-center, retrospective study that included 14 patients with nonunion after OWHTO between 2010 and 2018. The treatment for all patients consisted of local debridement and cancellous bone grafting at the osteotomy gap. Revision osteosynthesis due to a loss of correction/loosening of the locking screws or plates was performed in 5 patients. In 7 patients, lateral hinge fractures were treated with additional lateral plating. Union was confirmed using the modified "Radiographic Union Score for Tibial fractures". Outcome measure was the Lysholm Knee Score at final follow-up. The mean age of the patients included in our study was 48.4 ± 6.7years. Three patients were female (21.4%). The mean follow-up period was 20.8 ± 12.8months. Union was achieved in 12/14 patients (85.7%) after a mean of 6months (range, 3-13). The mean Lysholm Knee Score at the final follow-up was 83.2 ± 11.6. Two patients did not reach definitive union during the follow-up. In one patient, an infection of the nonunion following bone grafting was successfully treated with a two-stage procedure. Two patients needed additional cancellous bone grafting 6 and 8months after the first revision surgery. All patients showed pain-free full weight bearing after union was achieved. Nonunions after OWHTO can generally be treated successfully with cancellous bone grafting. For patients who have loss of correction, loosening of the osteosynthetic material or fracture of the lateral hinge, an additional revision or additive osteosynthesis may be required. Grade III.