Computer-assisted and patient-specific 3-D planning and evaluation of a single-cut rotational osteotomy for complex long-bone deformities

Malunion after long bone fracture results in an incorrect position of the distal bone segment. This misalignment may lead to reduced function of the limb, early osteoarthritis and chronic pain. An established treatment option is a corrective osteotomy. For complex malunions, a single-cut rotational osteotomy is sometimes preferred in cases of angular deformity in three dimensions. However, planning and performing this type of osteotomy is relatively complex. This report describes a computer-assisted method for 3-D planning and realizing a single-cut rotational osteotomy with a patient-specific cutting guide for orienting the osteotomy and an angled jig for adjusting the rotation angle. The accuracy and reproducibility of the method is evaluated experimentally using plastic bones. In addition, complex rotational deformities are simulated by a computer to investigate the relation between deformity and correction parameters. The computed relation between deformity and correction parameters enables the surgeon to judge the feasibility of a single-cut rotational osteotomy. This appears possible for deformities combining axial misalignment with sufficient axial rotation. The proposed 3-D method of preoperative planning and transfer with a patient-specific cutting guide and angled jig renders the osteotomy procedure easily applicable, accurate, reproducible, and is a good alternative for complex and expensive navigation systems

A 3D mathematical model for planning ostectomy on long-bone angular deformities

This study describes a 3D mathematical model for planning a corrective ostectomy on long bones with angular deformities based on CT imaging. The use of three-dimensional information allows the model to compute and correct the bone angulation and rotation. The cutting point selection is developed minimizing the bone length reduction inherent in an ostectomy process. An example of its application on a two year old dog is shown at the end of the paper.Veterinari

Single-cut osteotomy for correction of a complex multiplanar deformity of the radius in a Shetland pony foal

Objective To describe the surgical correction of a multiplanar deformity of the radius in a pony using a single-cut osteotomy. Study design Case report. Animals A 9-week-old male Shetland pony foal with a bodyweight of 47 kg. Methods The foal presented with a complex multiplanar deformity of the right radius. A 3-dimensional model of the bone was created based on computed tomography (CT) imaging. To correct the deformity, the cutting plane for a single-cut osteotomy was calculated following the mathematical approach described by Sangeorzan et al. After osteotomy, the bone was realigned and stabilized with two 4.5 locking compression plates (LCPs). Results Recovery from surgery was uneventful, and the foal remained comfortable. A CT exam 15 weeks after surgery revealed that diaphyseal deformities improved substantially in procurvatum (from 8° to 1°), varus (from 27° to 0°), and rotation (30° to 5°). The operated radius was 2.1 cm shorter than the left. Eighteen-month follow up confirmed a functionally and cosmetically acceptable outcome. Conclusion The single-cut osteotomy resulted in the successful correction of a multiplanar equine long-bone deformity with a favorable outcome in a Shetland pony. Clinical significance Single-cut osteotomy is an alternative surgical technique for the correction of complex diaphyseal long-bone equine deformities. Computed tomography data and the possibility of printing 3D models provides a significant advantage for rehearsing the procedure and for evaluating the correction that was achieved

Use of a Customized Device for Correction of Antebrachial Angular Deformity in a Dog

Angular deformity is a common condition in dogs that can cause serious malformations and is a challenge for surgeons to correct. A 15-month- old male Saint Bernard was evaluated due toright foreleg lameness. Orthopedic examination revealed a valgus deformity with external rotation and anteversion of the forelimb. Carpal examination revealedthe decreased range of motion with slight disturbances in carpal flexion. Radiography of both forelimbs showed angular deviation because of possible premature physeal closure of the distal ulnar growth plate.Surgical intervention was selected to correct the angular deformity. A closed-wedge osteotomy was planned using 3D reconstruction, obtained via computed tomography (CT). In order to accomplish this, a custom-made device was developed to aid the surgeon in establishing the position and orientation of the cutting planes during the intervention.Long-term follow-up obtained 3 years after surgery revealed the correct ossification of the osteotomy and complete resolution of lameness. The main advantages of using a customized device obtained from 3D CT include the predictability and accuracy of the method. The device allows for correction of atriple-axis angular long bone deviation, with full opposition between the bone fragments after osteotomy and minor loss of length of the limb.Ciencias Experimentale

Three-dimensional virtual planning of corrective osteotomies of distal radius malunions: a systematic review and meta-analysis

The purpose of this study was to summarize and evaluate results of three-dimensional (3D-) planned corrective osteotomies of malunited distal radius fractures. 3D-planning techniques provide the possibility to address 3D-deformity that conventional planning methods might not address. We systematically searched PubMed, EMBASE and the Cochrane library for studies that performed a 3D-planned corrective osteotomy on patients with a malunited distal radius fracture. Fifteen studies with a total of 68 patients were included in the analysis. In 96% of cases, the preoperatively present palmar tilt, radial inclination and ulnar variance showed statistically significant improvement postoperatively with restoration to within 5° or 2 mm of their normal values. Mean flexion–extension, pro-supination and grip strength showed statistically significant improvement (p < 0.05). Complications were reported in 11 out of 68 patients (16%). With the current advances in 3D printing technology, 3D-planned corrective osteotomies seem a promising technique in the treatment of complex distal radius malunions. Level of evidence IV Systematic review of case series, Level IV

Malunited forearm fractures in children

A malunion occurs when a fracture heals in a non-anatomical position. Fractures in growing children possess a capacity for remodeling and will correct angular deformity in time. Thus, a distal forearm fracture with some degree of displacement or angulation can be safely accepted in the expectance that remodeling will occur. In contrast, for midshaft forearm fractures, growth will not correct angular deformity as it does in distal fractures. Although orthopedic surgeons worldwide encounter pediatric forearm fractures very frequently, the decision as to whether accept, reduce or operate traumatic pediatric forearm fractures is often based on gut feeling and rarely based on objective criteria. This thesis aims to provide a backbone when opting for the best treatment strategy when you find yourself in another classic, ever-returning treatment dilemma regarding a child with a forearm fracture. Furthermore, malunions in older children have less potential for remodeling, which can lead to disappointing clinical outcomes, especially a restriction in forearm rotation. A corrective osteotomy, a surgical intervention to restore normal bone alignment, may be considered for these patients. However, a corrective osteotomy is often a challenging surgical procedure. Three-dimensional (3D) planning of the osteotomy and 3D printing of patient-specific instruments (PSIs) can potentially simplify the operation. To investigate if this innovative technology will improve clinical results, we determined what functional gain and what accuracy of correction can be achieved after a 3D corrective osteotomy.<br/

Registration based assessment of femoral torsion for rotational osteotomies based on the contralateral anatomy

BACKGROUND Computer-assisted techniques for surgical treatment of femoral deformities have become increasingly important. In state-of-the-art 3D deformity assessments, the contralateral side is used as template for correction as it commonly represents normal anatomy. Contributing to this, an iterative closest point (ICP) algorithm is used for registration. However, the anatomical sections of the femur with idiosyncratic features, which allow for a consistent deformity assessment with ICP algorithms being unknown. Furthermore, if there is a side-to-side difference, this is not considered in error quantification. The aim of this study was to analyze the influence and value of the different sections of the femur in 3D assessment of femoral deformities based on the contralateral anatomy. MATERIAL AND METHODS 3D triangular surface models were created from CT of 100 paired femurs (50 cadavers) without pathological anatomy. The femurs were divided into sections of eponymous anatomy of a predefined percentage of the whole femoral length. A surface registration algorithm was applied to superimpose the ipsilateral on the contralateral side. We evaluated 3D femoral contralateral registration (FCR) errors, defined as difference in 3D rotation of the respective femoral section before and after registration to the contralateral side. To compare this method, we quantified the landmark-based femoral torsion (LB FT). This was defined as the intra-individual difference in overall femoral torsion using with a landmark-based method. RESULTS Contralateral rotational deviation ranged from 0° to 9.3° of the assessed femoral sections, depending on the section. Among the sections, the FCR error using the proximal diaphyseal area for registration was larger than any other sectional error. A combination of the lesser trochanter and the proximal diaphyseal area showed the smallest error. The LB FT error was significantly larger than any sectional error (p < 0.001). CONCLUSION We demonstrated that if the contralateral femur is used as reconstruction template, the built-in errors with the registration-based approach are smaller than the intraindividual difference of the femoral torsion between both sides. The errors are depending on the section and their idiosyncratic features used for registration. For rotational osteotomies a combination of the lesser trochanter and the proximal diaphyseal area sections seems to allow for a reconstruction with a minimal error