Soft-tissue reconstruction of the leg associated with the use of the Hoffmann external fixator

An Interference Inspection Algorithm of Limb and Hexapod Frame in the Treatment of Lower Limb Deformity

The Ortho-SUV frame is an innovative hexapod widely used in orthopedics for managing fractures and deformities. Avoidance of limb-frame interference is essential to verify the implementability of the pre-planned correction trajectory, as well as to maintain the continuity and security of the correction strategy. In this study, a novel interference inspection algorithm is developed to investigate the interaction of the limb and hexapod frame in the treatment of lower limb deformities. The algorithm is built on a minimum distance model of the cone frustum busbar and cylindrical axis using vector analysis. A pre-defined trajectory is generated by Cartesian coordinate path control. Subsequently, an interference case is performed through numerical simulation and motion simulation. The results show that the conclusion of numerical simulation and motion simulation are consistent, which prove the feasibility of the algorithm. The results also show that it is possible to identify the riskiest struts, which are prone to interfere with the limb, and the riskiest positions. The proposed algorithm can support the clinician in selecting the suitable frame configuration to avoid interference. The algorithm solves the problem that the interference can only be judged by clinical observation in the clinic.

Influence of parameter deviation on the closeness of the tibial limb and external fixator based on a novel collision detection algorithm

The Ortho-SUV frame (OSF) is a hexapod external fixator widely applied in orthopedics deformity correction. The possibility of collision between OSF's struts and the soft tissue is an essential but overlooked issue. To avoid the issue, a novel collision detection algorithm is established based on a cone-cylinder model of the tibial limb-strut interaction for detecting the closeness of the tibial limb and external fixator. The algorithm is constructed using the vector analysis based on the model of the minimum distance between the truncated cone generatrix and the cylinder axis. The motion simulation is performed on the overall alignment through the Solidworks-motion module to verify the feasibility of the algorithm. Subsequently, the installation parameter deviations of the bone-fixator system are described to investigate the influence of orientation and position deviation on the closeness of the tibial limb and external fixator through the numerical method. The investigation results show that the orientation deviation γ (around the z-axis), the position deviation τ₁ and τ₂ (along the x and y-axes, respectively) have greater sensitivity to closeness and the influence of multiple deviations on the closeness has the property of superposition. The proposed algorithm can assist clinicians to strictly design and appraise frame configurations prior to their application to avoid the collision between the external fixator and the limbs during the correction. It has great application significance in the development of computer-aided correction software.

Repair of pretibial atonic wound with long cross-leg flap

Soft-tissue defects of the pretibial region constitute a major reconstructive challenge because of the insufficiency of the local tissues. In such cases, a long cross-leg flap may be an alternative option. This study presents a case with an atonic wound in the pretibial region caused by a previous traffic accident, which had received cross-leg flap repair following the excision.

Cross-leg flap: Its role in limb salvage

BACKGROUND

Pedicled cross-extremity flaps for lower limb wound coverage have been replaced by free tissue transfer in the last two decades. However, there are certain difficult situations where the free flap cannot be employed and alternative methods are needed. We describe our experience with cross-leg flap in 18 patients for the reconstruction of difficult leg defects in which no suitable recipient vessels were available for microvascular anastomosis in the vicinity of the defect.

MATERIALS AND METHODS

18 patients (17 men and 1 woman) with mean range 31.5 yrs(range 18-70 yrs) grade III B tibial fractures were included in the study. fasciocuteneous cross leg flap was employed and extremities were immobilized by external Fixator.

RESULTS

Fifteen flaps were completely available with two had marginal necrosis and one supsficial epidermal necrosis. No complications were related to the donor site, flap, or by immobilization are noted. Each patient resumed essentially normal gait and activity without any stiffness of joints related with the flap or external fixator.

CONCLUSION

The addition of external fixator stabilization aids greatly in wound care, as well as for general ease of the patient mobility and positioning. Cross-leg flap offers the possibility of salvaging limbs that are otherwise nonreconstructable.

Aggressive treatment of 119 open fracture wounds

BACKGROUND

The purpose of this study was to determine whether immediate primary closure of open fracture wounds can be performed without increasing the incidence of infections and delayed unions/nonunions. Although the traditional management of these injuries has been open treatment, a trend toward immediate primary closure has evolved on our service.

METHODS

All open fractures presenting to an urban Level I trauma center during a 42-month period were reviewed. Of the 127 patients with open fractures, 90 patients (119 open fractures) were initially treated at the above institution within 24 hours of injury, had fractures proximal to the carpus or tarsals, and were followed-up until fracture union. All patients underwent emergent wound irrigation and debridement. The method of fracture immobilization and timing of wound closure was left to the discretion of the attending orthopedic surgeon. Immediate primary closure was used in 22 of 25 Grade I open fractures (88%), 37 of 43 Grade II fractures (86%), 24 of 32 Grade IIIa fractures (75%), 4 of 12 Grade IIIb fractures (33%), and 0 of 7 Grade IIIc fractures (0%).

RESULTS

Eight fractures (7%) were complicated by a deep wound infection/osteomyelitis, and 19 fractures (16%) developed a delayed union/nonunion. Statistical analysis revealed no significant difference in delayed/nonunion and infection rates between immediate and delayed closures.

CONCLUSION

Immediate primary closure of open fracture wounds after a thorough debridement by an experienced fracture surgeon appears to cause no significant increase in infections or delayed union/nonunions. In addition, early closure may decrease the requirement for subsequent debridements and soft-tissue procedures, thereby minimizing surgical morbidity, shortening hospital stays, and reducing costs. We feel that a randomized, prospective study of this aggressive approach to open fracture care is warranted.

Treatment of compound fractures

Management of compound fractures remains a challenge to the surgeon. Methods to decrease patient morbidity include early fracture stabilization and sequential débridement. External fixation remains the standard; however, early internal fixation in low-grade injuries may be an acceptable option. Early soft tissue coverage is critical. The use of prophylactic parenteral antibiotics has decreased the incidence of acute infection and chronic osteomyelitis. Supplemental use of local antibiotic polymethyl methacrylate (PMMA) beads appears to further diminish the morbidity in high-grade open fractures.