In vivo test of a radiography-based navigation system for control of derotational osteotomies

Management of rotational malalignment following operative treatment of fractures of the lower extremities. A scoping review

BACKGROUND

Rotational malalignment after operative fracture treatment of the lower extremity may be associated with increased pain and functional impairment. Despite its clinical relevance, there are no uniform management guidelines. The aim of this scoping review is to provide an overview of all available evidence to diagnose and treat rotational deformities of the lower extremity following operative fracture treatment.

METHODS

This scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A literature search was carried out on 22 August 2023 by two independent reviewers in the Pubmed (MEDLINE), Embase, Web of Science, and Cochrane library databases. The search strategy was developed with the assistance of a biomedical information specialist. The main search terms were tibial and femoral malrotations. Disagreements were resolved through discussion with a third reviewer.

RESULTS

After screening and quality assessment of 3929 unique identified records, 50 articles were included for qualitative synthesis. Most studies were retrospective case reports or case series. Thirty studies focused on the femur, 11 on the tibia and nine included both femur and tibia. Most of the included studies presented cases where malrotation was associated with other limb deformities. Only 18 studies focused solely on the treatment of malrotation of the lower extremities after operative fracture treatment. Regarding diagnosis, bilateral CT-scans were used in 34 studies. Regarding treatment, external fixation was used in two studies, internal fixation (either intramedullary nail or plate) in 45 studies, and in three studies the authors used both. Overall, revision surgery resulted in good clinical outcomes with low complication rates.

CONCLUSION

This scoping review reveals that rotational malalignment following operative treatment of lower extremity fractures remains an important complication. Although it occurs frequently and is associated with severe disability for the patient, standardized guidelines regarding the terminology, diagnosis, indications for intervention and treatment are lacking. CT-scan is the most used diagnostic modality in daily clinical practice. Revision surgery, using diverse operative techniques, demonstrated positive results, significantly alleviating patient complaints with few complications. Nevertheless, an international consensus regarding the optimal management pathway is needed, and future prospective clinical studies seem therefore necessary.

Generic Implant Positioning Technology Based on Hole Projections in X-Ray Images

Implant placement plays a key role in trauma and orthopedics. In this paper, a generic technological concept for implant positioning assistance is outlined. The system utilizes conventional radiographic devices for imaging and tracking and embeds into surgical workflows without the need for complex navigation equipment. It is based on feature extraction from cylindrical hole-projections in X-ray images for determining spatial alignment of implant and anatomy. Basic performance of a prototype system was experimentally verified in terms of tracking accuracy and robustness under varying conditions. In a second step, the system was developed into a set of application modules, each serving a pressing clinical need: Plating of the proximal humerus, cephalic nail and dynamic hip-screw placement, general anatomic plating, distal nail interlocking with adjustment of femoral anteversion and corrective osteotomies. Module prototypes were tested according to their degree of maturity from feasibility assessment in wet-labs to clinical handling tests. Orientation tracking of reference objects yielded an accuracy and precision of 0.1±0.71 deg (mean±standard deviation) with a maximum error of 4.68 deg at unfavorable conditions. This base-performance translated, e.g., into a precision of ±1.2 mm (standard deviation) screw-tip to joint distance at proximal humerus plating, or into a precision of lag screw positioning in the femoral head of ±0.6 mm in craniocaudal and ±1.6 mm in anterioposterior direction. The concept revealed strong potential to improve surgical outcomes in a broad range of orthopedic applications due to its generic and simplistic nature. Comprehensive validation activities must follow for clinical introduction.