Accuracy of a hexapod parallel robot kinematics based external fixator.

BACKGROUND: Different hexapod-based external fixators are increasingly used to treat bone deformities and fractures. Accuracy has not been measured sufficiently for all models. METHODS: An infrared tracking system was applied to measure positioning maneuvers with a motorized Precision Hexapod® fixator, detecting three-dimensional positions of reflective balls mounted in an L-arrangement on the fixator, simulating bone directions. By omitting one dimension of the coordinates, projections were simulated as if measured on standard radiographs. Accuracy was calculated as the absolute difference between targeted and measured positioning values. RESULTS: In 149 positioning maneuvers, the median values for positioning accuracy of translations and rotations (torsions/angulations) were below 0.3 mm and 0.2° with quartiles ranging from -0.5 mm to 0.5 mm and -1.0° to 0.9°, respectively. CONCLUSIONS: The experimental setup was found to be precise and reliable. It can be applied to compare different hexapod-based fixators. Accuracy of the investigated hexapod system was high.

Polyaxial Locked Implants in the Treatment of Type Vancouver B1 Periprosthetic Fractures of the Femur: Retrospective Clinical Examination in 58 Cases with Review of the Literature.

We concluded a retrospective study of the outcomes of a consecutive series of Vancouver B1 and C femoral injuries using two specific locked implants. The study center is a dedicated trauma hospital with a large catchment area. Over a five-year period we treated 58 patients with a periprosthetic fracture of the femur with an angular stable plate, defined as the index procedure. The mean age at the index procedure was 72.4 years; 40 patients were female (69%). In 32 cases (55.2%) we saw a hip endoprosthesis, in 21 cases (36.2%) a knee endoprosthesis, and in five cases both (8.6%). Outcome measures were intra- and postoperative complications, bony union, degree of mobility and social status with comparison to the preoperative status, Barthel index, and timed ''up and go'' test. Union occurred in 56 cases (96.5%) after the index procedure. Three patients were bedridden before the injury; the remainder regained full weight-bearing status. The mean duration until full weight-bearing status in these patients was 8.6 weeks (4-13). Early implant failure with proximal dislocation of the screws occurred in two cases (3.5% revision rate). At follow up, 78% had maintained the same social status as before the injury. Fifty-two patients (89%) had regained their previous level of mobility. The mean Barthel index was 85 points (70-100) out of a possible 100, and improved from a mean of 35 points at the start of rehabilitation. It decreased on average by ten points compared to the preoperative status. The mean ''up and go'' time was measured as 21.4 s. In conclusion, polyaxial plates can achieve excellent surgical results. On the other hand, patients with this type of injury exhibit a clear deterioration in their social status, especially regarding lower limb motor function and self-independence.

Is the Wave Plate Still a Salvage Procedure for Femoral Non-union? Results of 75 Cases Treated with a Locked Wave Plate.

OBJECTIVE: To analyse the results of the treatment of aseptic femoral non-unions using a singular locked implant. DESIGN: Consecutive case series. SETTING: A level-1 trauma center with a high number of specialist referrals. PATIENTS: The study is based on a consecutive series of patients with prospective data evaluation. From 1993 to 2003, 75 patients were treated with a wave plate. All patients had persistent non-union of the femoral shaft without clinical or laboratory signs of infection and previous unsuccessful attempts to treat the non-union. INTERVENTION: The method of treatment was standardized and included a lateral approach, cancellous bone hip grafting, osteosynthesis with a wave-shaped plate (PPF) and polyaxial locking screws as well as the application of a gentamicin-PMMA chain. MAIN OUTCOME MEASUREMENTS: Time to achieve union, rate of implant failure and number of remaining nonunions after treatment. A total of 75 patients had full follow-up and were included in the study. RESULTS: The union of the fracture was found in 64 patients after the initial procedure. In eight cases a second procedure was performed to achieve union in the form of a second bone graft because of a delay in callus formation. The mean time to union was 7.3 months with a range from 3 to 19 months. The implant failed in three cases accounting for 4% of the total. CONCLUSION: The locked wave plate offers a further reliable treatment for complex aseptic femoral non-unions.

Treatment of Distal Lower Leg Fractures: Results with Fixed-Angle Plate Osteosynthesis.

Twenty-five patients with closed distal tibial fractures were treated with a fixed-angle (locked) plate osteosynthesis. The study period was from 1.1.06 to 31.12.07. According to AO classification, there were three A1, eight A2, nine A3, one B2, two C1, and two C3 fractures. All patients had a follow up examination after an average of 16.6 months. Complications included a technical mistake (fixation in slight malangulation), two infections, and one non union that showed consolidation after 15 months. All other patients reached bone consolidation and full weight bearing after an average of 3.5 months. The ankle range of motion for all patients was, on average, flexion/extension 18°/35°, without restrictions on the walking distance. No loss of reduction occurred. Fixed-angle plate osteosynthesis is a good alternative to intramedullary nailing when treating closed distal lower leg fractures. It is a demanding surgical method with good clinical and functional results.

Operative Treatment and Soft Tissue Management of Open Distal Tibial Fractures - Pitfalls and Results.

Open tibial fractures usually result from high-energy trauma. Severe soft-tissue injuries are often combined with open fractures of the distal tibia. A consecutive series of 42 patients with open extraarticular distal tibial fractures (Gustilo I-IIIc) operated on between July 2006 and February 2009 were included in the study reported here. We performed open reduction and internal fixation for the Gustilo I cases. Soft tissue was closed directly after antibiotic beads had been temporarily applied. For the Gustilo II and III cases, our treatment protocol included soft-tissue debridement of all devitalized soft tissue and bone fragments, pulsatile jet irrigation, and external stabilization. Soft tissue was temporarily closed with Epigard_ after the application of antibiotic beads. A second-look operation was scheduled after 3-5 days. Gustilo II patients needed an average of 1.1 (0-3) revisions until wound closure, compared to the average of 2.1 revisions necessary for the Gustilo III patients. It took 5.6 (0-16) days to obtain definitive wound closure in the Gustilo II patients and 9.9 (3-28) days in the Gustilo III patients. Skin grafting was sufficient for definitive softtissue closure in ten cases, local flaps in eight cases, and free musculocutaneous flaps were needed in six cases. Gustilo II patients with primary wound closure remained hospitalized for 11 days, while patients with secondary wound closure stayed in hospital for an average of 20 days. Our early results concerning infection rate, number of reoperations, and time to bony consolidation can be compared with other studies. Functional results will have to be evaluated at clinical follow-up.

Unstable Cervical Spinal Injury in Children - Case Report and Review of the Literature.

Large studies about the management of pediatric patients with unstable flexion-distraction injuries of the midcervical spine are rare. We present the case of a 12-year-old girl who sustained a cervical spinal injury with unilateral facet dislocation and discuss details and problems of diagnostic procedures and treatment in the light of the recent literature. The management and pitfalls of a unilateral facet dislocation in a child are summarized. After initial reposition, a multisegmental instability with neurology developed. Although distraction-flexion cervical spine injuries are common in adults and often occur with concomitant neurological sequelae, they also can occur in the pediatric population. In conclusion, an MRI seems advisable. A treatment of postoperative malalignment with reposition via a halo-fixator cannot be recommended. Repositioning is possible but was lost when the fixator was removed. Comparing the historic and recent literature there is only weak evidence overall, nevertheless a ventral fusion seems to be the treatment option of choice.

Septic arthritis of the knee after anterior cruciate ligament surgery: a stage-adapted treatment regimen.

BACKGROUND: Septic arthritis is a rare complication after anterior cruciate ligament surgery. All case series reported so far have been retrospective, and case numbers of septic arthritis have ranged from 4 to 11. HYPOTHESIS: A stage-adapted treatment regimen for septic arthritis after anterior cruciate ligament surgery can provide reliable results. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From June 1993 to May 2003, 24 patients met the inclusion criteria for this study. The average age at trauma was 32.5 years. Treatment protocol was based on the grade of infection. Options included transarthroscopic treatment for Gaechter grades 1 and 2 infections or medial and lateral arthrotomy for grades 3 and 4 infections. Graft retention was decided based on clinical findings. The setting was a specialized trauma hospital. Follow-up included International Knee Documentation Committee forms, radiographs, and the Tegner and Lysholm scores at a mean of 66 months (range, 11-142) after treatment. RESULTS: In all cases, treatment of infection was successful; overall, a mean of 2.2 operations were required. In 7 cases, it was possible to salvage the graft. The Tegner activity level before the knee injury was 6.1 points. At follow-up, the average score was 3.8 points. The postoperative subjective International Knee Documentation Committee score averaged 64. The mean Lysholm score was 65.6. On clinical examination, a mean extension deficit of 3 degrees and a mean maximum flexion of 120 degrees were found. In the single-legged hop test, a mean capacity of 63% compared with the uninjured side was measured. CONCLUSION: The described treatment regimen gives reliable results for this complication. There were no recurrences of septic arthritis or bone infection. Early infection can be managed arthroscopically with satisfactory results regarding the treatment of infection. In advanced or chronic infection, a more radical approach seems favorable. Results in these cases are overall only fair compared with patients with an uncomplicated anterior cruciate ligament reconstruction.

Cardial gunshot injury: treatment in a trauma hospital without a cardiac unit.

Gunshot injuries to the chest often require urgent admission to the nearest hospital, because of the cardiorespiratory status, transfer to a hospital without a cardiothoracic unit might be unsafe. In this case, a male patient was transferred to the nearest hospital on being shot through the heart. On admission, he was in shock, and immediate surgery was performed. We report our treatment regime for thoracic injuries and the specific management of this patient. We conclude that every hospital with an accident and emergency department has to be prepared for such an injury and that operative management is possible without cardiopulmonary bypass.

Delayed and non-union of the humeral diaphysis--compression plate or internal plate fixator?

In a retrospective study, two groups of patients with delayed or non-union of the humeral diaphysis were compared. In group A, a 4.5-mm low-contact dynamic compression plate (LCDCP) was used for internal fixation and in group B, an internal plate fixator with locked screws was used. In all patients autologous bone grafting was performed. Group A consisted of 14 patients (mean age 38.9 years) and group B consisted of 19 patients (mean age 54.3 years). The mean duration of the delayed or non-union was 9.3 months (range 3-26 months) in group A and 24.8 months (range 3-216 months) in group B. In group A an average of 1.1 (range 0-2) previous operations had been performed, and in group B an average of 1.6 (range 0-4). One primary nerve palsy was diagnosed in group A and six in group B. Although the patients of group B were older, had longer-lasting non-unions, more previous operations and more severe initial injuries, only in group A was there a hardware failure due to osteoporosis which required re-osteosynthesis. All other patients showed bony consolidation without further operations. The LCDCP and the internal plate fixator both showed high consolidation rates, but we feel that the internal plate fixator may be the more reliable implant, especially in patients with poor bone stock.