Comparison of double chevron-cut and biplanar distal femoral osteotomy techniques: A biomechanical study.

OBJECTIVE: This study aimed to compare the stability and mechanical properties of the double chevron-cut (DCC) and biplanar (BP) distal femoral osteotomy (DFO) techniques, along with analyzing their respective contact surface areas. METHODS: Biomechanical testing was performed using sawbone and 3D modeling techniques to assess axial and torsional stability, torsional stiffness, and maximum torque of both osteotomy configurations. Additionally, 3D models of the sawbone femur were created to calculate and compare the contact surface area of the DCC, BP, and conventional single-plane DFO techniques. RESULTS: Axial stiffness and maximum strength did not significantly differ between the two osteotomy techniques. However, in terms of torsional properties, the DCC technique exhibited superior torsional stiffness compared to the BP group (27 ± 7.7 Nm/° vs. 4.5 ± 1.5 Nm/°, p = 0.008). Although the difference in maximum torque did not reach statistical significance (63 ± 10.6 vs. 56 ± 12.1, p = 0.87), it is noteworthy that the DCC group sawbone model exhibited fracture in the shaft region instead of at the osteotomy site. Therefore, the actual maximum torque of the DCC construct may not be accurately reflected by the numerical values obtained in this study. The contact surface area analysis revealed that the BP configuration had the largest contact surface area, 111% larger than that of the single-plane configuration. but 60% of it relied on the less reliable axial cut. Conversely, the DCC osteotomy offered a 31% larger contact surface area than the single-plane configuration, with both surfaces being weight-bearing. CONCLUSION: The DCC osteotomy exhibited superior mechanical stability, showing improved rotational stiffness and maximum torque when compared to the BP osteotomy. Although the BP osteotomy resulted in a larger contact surface area than the DCC osteotomy, both were larger than the conventional single-plane configuration. In clinical practice, both the DCC and BP techniques should be evaluated based on patient-specific characteristics and surgical goals.

The benefits of a percutaneous supplemental screw to reinforce the hinge of a medial open wedge tibial osteotomy.

INTRODUCTION: Our earlier studies reported that an additional lag screw placed from the opposite side increases the stability of the fixation construct in medial open wedge high tibia osteotomy (MOWHTO). The aim of the study was to evaluate the clinical relevance of the use of a supplemental screw with immediate post-operative full weight-bearing and its benefits in terms of functional outcome, radiographic outcome and complications. MATERIALS AND METHODS: A retrospective study was performed comparing the historical cohort (MOWHTO without opposite screw) (group A) with the current cohort (MOWHTO with opposite screw) (group B). The patients underwent clinical and radiological assessments. We evaluated the WOMAC (The Western Ontario and McMaster Universities) score, IKDC (International Knee Documentation Committee) scores, and Lysholm knee score. Patients' return to sports and work were also recorded. RESULTS: We included 123 knees receiving MOWHTO alone (group A) with 114 knees (group B) receiving MOWHTO with an opposite screw. A shorter bone union time (18.3 ± 2.1 weeks v.s. 11.5 ± 2.6 weeks, p < 0.001), earlier return to sports (6.1 months vs. 4.6 months, p < 0.001) and return to works (3.2 months vs. 2.3 months, p < 0.001) and better 6-month functional outcomes were found in group B (p < 0.001). The complications were similar in both groups. One patient experienced irritation at the site of the screw entrance and the screw was removed after union. CONCLUSION: The current study evaluated the clinical efficacy of a supplemental lag screw placed from the opposite side in MOWHTO. Comparing to the plate alone, the additional opposite screw improved the implant and fixation stability under immediate weight-bearing without causing complications. A shorter time for returning to sports and work was noted, and a better functional outcome at 6-month follow-up was registered.

Patient-Specific Instrument Guided Double Chevron-Cut Distal Femur Osteotomy.

The risk of non-union and prolonged periods of protected weight-bearing still remain unsolved issues after distal femur osteotomy (DFO). To improve the stability, we developed the double chevron-cut technique, which is a modified medial closing-wedge DFO guided by a patient-specific instrument. The purpose of this study was to investigate the feasibility and outcome of this operative approach. Twenty-five knees in twenty-three consecutive patients with genu valgum and lateral compartment osteoarthritis that received double chevron-cut DFO were included. The target of correction was 50% on the weight-bearing line (WBL) ratio. Patient-reported outcomes included the Oxford Knee Score (OKS) and the 2011 Knee Society Score (KSS). The mean of the WBL ratio was corrected from 78.7% ± 12.0% to 48.7% ± 2.9% postoperatively. The mean time to full weight bearing was 3.7 ± 1.4 weeks. Union of the osteotomy was achieved at 11.3 ± 2.8 weeks. At a mean follow-up of 17 months, the OKS improved from a mean of 27.6 ± 11.7 to 39.1 ± 7.5 (p = 0.03), and the KSS from a mean of 92.1 ± 13.0 to 143.9 ± 10.2 (p < 0.001). Three patients developed complications, including one case of peri-implant fracture, one of loss of fixation, and one of non-union. The double chevron-cut DFO followed by immediate weight-bearing as tolerated is effective in treating genu valgum deformity and associated lateral compartment osteoarthritis.

Significantly reducing blood loss via a peri-articular injection of tranexamic acid during total knee arthroplasty: a retrospective study.

BACKGROUND: The administration of an intra-articular injection (IAI) of tranexamic acid (TXA) has been demonstrated to be effective in reducing both blood loss and transfusion rate during total knee arthroplasty (TKA); however, few studies have reported the efficiency of a peri-articular injection (PAI) of TXA. We studied the efficiency of a PAI of TXA in reducing blood loss during TKA. METHODS: Fifty patients undergoing primary simultaneous bilateral TKA were enrolled in this retrospective study. The right knee received a PAI of 1 g of TXA (Group I), and the left knee received an IAI of 1 g of TXA (Group II). The clinical outcome measures were a change in blood loss from Hemovac drains and surgical time. RESULTS: The decrease in blood loss from the Hemovac was significantly lower in Group I (460.1 ± 36.79 vs. 576.0 ± 34.01, P < 0.001) than in Group II, and no significant difference in surgical times was observed. The blood transfusion rate in the present study was 16 %. CONCLUSIONS: A PAI of TXA may reduce blood loss more efficiently than an IAI of TXA during TKA without increased complications such as surgical site infection, poor wound healing, skin necrosis, pulmonary embolism, and deep vein thrombosis.

Biomechanical evaluation of high tibial osteotomy plate with internal support block using finite element analysis.

BACKGROUND/OBJECTIVE: High tibial osteotomy (HTO) is a common treatment for medial knee arthrosis. However, a high rate of complications associated with a plate and a significant loss of correction have been reported. Therefore, an internal support block (ISB) is designed to enhance the initial stability of the fixation device that is important for successful bone healing and maintenance of the correction angle of the osteotomy site. The purpose of this study was performed to examine if an internal support block combined with a plate reduces the stress on the plate and screw area. METHODS: Finite element models were reconstructed following three different implant combinations. Two loading conditions were applied to simulate standing and initial sit-to-stand postures. Data analysis was conducted to evaluate the axial displacement of the posteromedial tibial plateau, which represents the loss of the posteromedial tibial plateau in clinical observation. Moreover, the stresses on the bone plate and locking screws were evaluated. RESULTS: Compared to the TomoFix plate, the ISB reduced the axial displacement by 73% and 76% in standing and initial sit-to-stand loading conditions, respectively. The plate with an ISB reduced stress by 90% on the bone plate and by 73% on the locking screw during standing compared to the standalone TomoFix plate. During the initial sit-to-stand loading condition, the ISB reduced the stress by 93% and 77% on the bone plate and the locking screw, respectively. CONCLUSION: The addition of the PEEK block showed a benefit for structural stability in the osteotomy site. However, further clinical trials are necessary to evaluate the clinical benefit of reduced implant stress and the internal support block on the healing of the medial bone tissue.

A supplemental screw enhances the biomechanical stability in medial open-wedge high tibial osteotomy.

BACKGROUND: The supplemental screw technique was introduced for salvage of lateral hinge fracture in medial open-wedge high tibial osteotomy (owHTO). The efficacy of its use in protection of lateral hinge fracture and corresponding biomechanical behaviors remained unclear. The current study was aimed to clarify if a supplemental screw can provide better protection to lateral hinge in biomechanical perspective. MATERIALS: An in vitro biomechanical test was conducted. Tibial sawbones, commercial owHTO plates and a cannulated screw were utilized for preparing the intact, owHTO, and owHTO with cannulated screw insertion specimens. A "staircase" dynamic load protocol was adopted for axial compressive test with increasing load levels to determine structural strength and durability by using a material testing system, while a motion capture system was applied for determining the dynamic changes in varus angle and posterior slope of the tibia plateau with various specimen preparation conditions. RESULTS: Type II lateral hinge fracture were the major failure pattern in all specimens prepared with owHTO. The insertion of a supplemental cannulated screw in medial owHTO specimens reinforced structural stability and durability in dynamic cyclic loading tests: the compressive stiffness increased to 58.9-62.2% of an intact specimen, whereas the owHTO specimens provided only 23.7-29.2% of stiffness of an intact specimen. In view of tibial plateau alignment, the insertion of a supplemental screw improved the structural deficiency caused by owHTO, and reduced the posterior slope increase and excessive varus deformity by 81.8% and 83.2%, respectively. CONCLUSION: The current study revealed that supplemental screw insertion is a simple and effective technique to improve the structural stability and durability in medial owHTO.

Clinical Experience Using a 3D-Printed Patient-Specific Instrument for Medial Opening Wedge High Tibial Osteotomy.

PURPOSE: High tibial osteotomy (HTO) has been adopted as an effective surgery for medial degeneration of the osteoarthritis (OA) knee. However, satisfactory outcomes necessitate the precise creation and distraction of osteotomized wedges and the use of intraoperative X-ray images to continually monitor the wedge-related manipulation. Thus HTO is highly technique-demanding and has a high radiation exposure. We report a patient-specific instrument (PSI) guide for the precise creation and distraction of HTO wedge. METHODS: This study first parameterized five HTO procedures to serve as a design rationale for an innovative PSI guide. Preoperative X-ray and computed tomography- (CT-) scanning images were used to design and fabricate PSI guides for clinical use. The weight-bearing line (WBL) of the ten patients was shifted to the Fujisawa's point and instrumented using the TomoFix system. The radiological results of the PSI-guided HTO surgery were evaluated by the WBL percentage and tibial slope. RESULTS: All patients consistently showed an increased range of motion and a decrease in pain and discomfort at about three-month follow-up. This study demonstrates the satisfactory accuracy of the WBL adjustment and tibial slope maintenance after HTO with PSI guide. For all patients, the average pre- and postoperative WBL are, respectively, 14.2% and 60.2%, while the tibial slopes are 9.9 and 10.1 degrees. The standard deviations are 2.78 and 0.36, respectively, in postoperative WBL and tibial slope. The relative errors of the pre- and postoperative WBL percentage and tibial slope averaged 4.9% and 4.1%, respectively. CONCLUSION: Instead of using navigator systems, this study integrated 2D and 3D preoperative planning to create a PSI guide that could most likely render the outcomes close to the planning. The PSI guide is a precise procedure that is time-saving, radiation-reducing, and relatively easy to use. Precise osteotomy and good short-term results were achieved with the PSI guide.

Importance of a moderate plate-to-bone distance for the functioning of the far cortical locking system.

The far cortical locking (FCL) system, a novel bridge-plating technique, aims to deliver controlled and symmetric interfragmentary motion for a potential uniform callus distribution. However, clinical data for the practical use of this system are limited. The current study investigated the biomechanical effect of a locking plate/far cortical locking construct on a simulated comminuted diaphyseal fracture of the synthetic bones at different distance between the plate and the bone. Biomechanical in vitro experiments were performed using composite sawbones as bone models. A 10-mm osteotomy gap was created and bridged with FCL constructs to determine the construct stiffness, strength, and interfragmentary movement under axial compression, which comprised one of three methods: locking plates applied flush to bone, at 2 mm, or at 4 mm from the bone. The plate applied flush to the bone exhibited higher stiffness than those at 2 mm and 4 mm plate elevation. A homogeneous interfragmentary motion at the near and far cortices was observed for the plate at 2 mm, whereas a relatively large movement was observed at the far cortex for the plate applied at 4 mm. A plate-to-bone distance of 2 mm had the advantages of reducing axial stiffness and providing nearly parallel interfragmentary motion. The plate flush to the bone prohibits the dynamic function of the far cortical locking mechanism, and the 4-mm offset was too unstable for fracture healing.

Morphometric Analysis of the Clavicles in Chinese Population.

The clavicle has a complex geometry that makes plate fixation technically difficult. The current study aims to measure the anatomical parameters of Chinese clavicles as reference for plate design. One hundred clavicles were analyzed. The clavicle bone model was reconstructed by using computed tomography images. The length, diameters, and curvatures of the clavicle were then measured. The female clavicle was shorter, more slender, and less curved in lateral part than the male clavicle. There was a positive relationship between height and clavicle parameters except lateral curve and depth. The measurements of Chinese clavicles were generally smaller than Caucasians. The clavicle curves were correlated with the bone length; thus consideration of the curve variations may be necessary as designing size distribution of clavicle plate.

Measurement of Tip Apex Distance and Migration of Lag Screws and Novel Blade Screw Used for the Fixation of Intertrochanteric Fractures.

Fixation with a dynamic hip screw (DHS) is one of the most common methods for stabilizing intertrochanteric fractures, except for unstable and reverse oblique fracture types. However, failure is often observed in osteoporotic patients whereby the lag screw effectively 'cuts out' through the weak bone. Novel anti-migration blades have been developed to be used in combination with a lag screw ('Blade Screw') to improve the fixation strength in osteoporotic intertrochanteric fractures. An in-vitro biomechanical study and a retrospective clinical study were performed to evaluate lag screw migration when using the novel Blade Screw and a traditional threaded DHS. The biomechanical study showed both the Blade Screw and DHS displayed excessive migration (≥10 mm) before reaching 20,000 loading cycles in mild osteoporotic bone, but overall migration of the Blade Screw was significantly less (p ≤ 0.03). Among the patients implanted with a Blade Screw in the clinical study, there was no significant variation in screw migration at 3-months follow-up (P = 0.12). However, the patient's implanted with a DHS did display significantly greater migration (P<0.001) than those implanted with the Blade Screw. In conclusion, the Blade Screw stabilizes the bone fragments during dynamic loading so as to provide significantly greater resistance to screw migration in patients with mild osteoporosis.