M. Ehlinger

Interprosthetic femoral fractures: analysis of 14 cases. Proposal for an additional grade in the Vancouver and SoFCOT classifications.

INTRODUCTION Interprosthetic fracture is a rare but serious entity, impairing consolidation and stability due to adverse mechanical conditions related to bone fragility and implant volume. OBJECTIVE The present study highlights the difficulties involved in managing such fractures, details treatment options and reports findings leading to a proposed additional grade in the comparable Vancouver (hip) and French Orthopedic and Traumatologic Surgery Society (Société française de chirurgie orthopédique et traumatologique: SoFCOT) (knee) classification systems. PATIENTS AND METHODS A multicenter retrospective series included 14 interprosthetic femoral fractures: eight type double C (typeC for both hip and knee), five type C for hip and B for knee, and one type double B (type B for both hip and knee) on the Vancouver and SoFCOT classifications. Fracture occurred on standard (n=15) or revision (n =13) implants. Six cases involved a femoral shaft encumbered by a total knee replacement (TKR) femoral extension stem and eight cases TKR without femoral long stem, assimilable to type C fracture. RESULTS None of the six fractures proximal to a constrained TKR with stem-achieved union by primary intention, whereas seven of the eight type-C fractures did so. Finally, 12 cases showed favorable evolution, with three secondary total femur replacements (TFR) and one death at 6 months without bony union or revision and one patient waiting for TFR. DISCUSSION To describe the status of the intermediate femur and its medullary canal encumbrance, we propose adding a category D to the SoFCOT and Vancouver classifications, corresponding to interprosthetic fracture on TKR with diaphyseal extension stem. Interprosthetic fracture internal fixation should begin with long devices bridging the two prostheses. When the implant is loose, it may be replaced; in case of diaphyseal extension, however, the residual femur between the two extensions should be protected against peak stress by a plate extending upward and downward. In case of limited bone stock, due to osteolysis or initial femoral medullary canal compromise, especially if one or both implants are loose, TFR may be indicated as consolidation, is jeopardized by the uncertain mechanical situation.

Technical difficulties in hardware removal in titanium compression plates with locking screws.

UNLABELLED With the advent of locking screws fixation devices, came new problems when removing internal fixation hardware. The objective of this study was to evaluate these problems and their possible solutions. The first problem was screws jamming on the plate, secondary to either initial poor screwing technique (with inadequate placement of the targeting device) or use of excessive force (when screwing in the screws without using the torque-controlling screwdriver). Treatment consists of destroying the screw heads using tungsten drills. The screw bodies can then be extracted using a trephine drill. The second problem involves destruction of the recess of the screw head. It can be secondary to overly forceful screw insertion or risky screw extraction. This can be treated using a specific conical left-turn screwdriver, assuming that the screw/plate thread is still intact. Finally, the screw recess can be filled. The plate itself may be a source of problems when being extracted because the screw holes left free also have been filled. Lever arm maneuvers to raise the fibrous bridges and substantial traction along the axis can be useful. These problems are more frequent with minimally invasive surgery. The consequences of this fixation types hardware removal surgery are multiple: lengthened operative time, risk of secondary maximally invasive surgery, presence of metallic shavings residues in cases of screw head destruction, and the risk of iterative fracture secondary to trephine drill use. Prevention is thus essential. It is based on rigorous technique in placing the targeting device, drilling, and inserting screws, the systematic use of the torque-controlling screwdriver, and the verification of proper screw position. The locking compression plate (LCP) material is highly effective but its removal should not become challenging. LEVEL OF EVIDENCE Level V.

Early prediction of femoral head avascular necrosis following neck fracture.

Femoral neck fracture puts at risk functional prognosis in young patients and can be life-threatening in the elderly. The present study reviews methods of femoral head vascularity assessment following neck fracture, to address the following issues: what is the risk of osteonecrosis? And what, in the light of this risk, is the best-adapted treatment to avoid iterative surgery? Femoral head vascularity depends on retinacular vessels and especially the lateral epiphyseal artery, which contributes from 70 to 80% of the femoral head vascular supply. Fracture causes vascular lesions, which are in turn the prime cause of necrosis. Other factors combine with this: hematoma tamponade effect, reduced joint space and increased pressure due to lower extremity positioning in extension/internal rotation/abduction during surgery. Head deformity is not due to direct cell death but to the repair process originating from the surrounding living bone. In post-traumatic necrosis, proliferation rapidly invades the head, with significant osteogenesis. Pathologic fractures occur at the boundary between the new and dead bone. Many techniques have been reported to help assess residual hemodynamics and risk of necrosis. Some are invasive: superselective angiography, intra-osseous oxygen pressure measurement, or Doppler-laser hemodynamic measurement; others involve imaging: scintigraphy, conventionnal or dynamic MRI. The future seems to lie with dynamic MRI, which allows a new classification of femoral neck fractures, based on a non-invasive assessment of femoral head vascularity.

Minimally-invasive fixation of distal extra-articular femur fractures with locking plates: Limitations and failures

Minimally-invasive fixation using a locking plate and early motion is normal practice. However, technical errors and pitfalls are common. This surgery has a set of rules that encompass both the mechanics of the internal fixation system and the implantation itself. If these rules are not strictly followed, alignment defects and/or early failure of the fixation can occur. We analysed four cases of clinical failure that were encountered after minimally-invasive distal femoral extra-articular fixation with locking plates. The following rules must be followed with this technique: extra-articular fracture, minimally-invasive approach, long plate alternating between locking screw and empty hole (five holes on either side of fracture), bi-cortical screws, placement of locking screws near a complex fracture but away from a simple fracture. Osteoporotic bone, obesity that interferes with the instrumentation, articular fracture, horizontal fracture line and surgeon experience are all limitations of this minimally-invasive technique.

Minimally invasive locking screw plate fixation of non-articular proximal and distal tibia fractures.

Intramedullary nailing of proximal and distal quarter tibia fractures is known to be a challenging procedure due to the metaphyseal enlargement, the reduced contact between implant and cortex and fracture comminution. Therefore, some authors suggest preferring the use of plate internal fixation in the management of these challenging fractures. The purpose of this manuscript is to present and describe our technique of minimally invasive locking plate osteosynthesis in the treatment of extra-articular proximal and distal tibia fractures. Osteosynthesis was performed by means of a locking screw plate system which construct characteristics usually allow immediate weight-bearing and early functional mobilization. This minimally invasive surgical procedure advantageously combines the principles of closed fixation with construct stability.

Minimally-invasive internal fixation of extra-articular distal femur fractures using a locking plate: Tricks of the trade

Fractures of the distal femur are rare and occur in two distinct population categories: young patients after high energy traumas and elderly patients who fall from their full height, and often carry severe co-morbidities making especially difficult to manage theses complex injuries. In elderly patients the potential complications are numerous including infection, non-union and frequent function deterioration. We present a technique of minimally invasive internal fixation of the distal extra-articular femur using a locking plate and present the tricks of the trade to obtain successful reduction and achieve union. The hardware used includes plate fixation with a large fragment locking screw. This minimally invasive surgery combines stability of the internal fixation device with the principles of closed surgery, allowing early mobilization and immediate weight bearing to warrant good functional recovery.

Survivor of a traumatic atlanto-occipital dislocation

Atlanto-occipital dislocation is a devastating ligamentous injury that most often turns fatal. However, because of on-site resuscitation improvements, the emergency teams are increasingly dealing with this condition. We report a rare case of atlanto-occipital dislocation (AOD) in a surviving patient with more than one-year follow-up. The mechanism of injury appears to be an extreme hyperextension applied to the head. This injury occurs more frequently in children since they are anatomically predisposed (flat articulation between the occiput and the atlas, increased ligamentous laxity). The diagnosis should be suggested by severe neurological injury after high trauma but also post-traumatic cardiorespiratory deficit. There have been reports of atlanto-occipital dilocations without neurologic impairment. A radiographic examination must be performed and lateral cervical radiographs should be acquired. However, additional imaging with CT or MRI may be required to aid diagnosis of AOD in cases in which radiographic findings are equivocal. Once the diagnosis of AOD has been confirmed, an anatomical classification should be made according to the magnitude of displacement. Fatal lesions are of neurological and vascular origin and some authors advocate the systematic use of angiography. Consensus regarding the management of AOD in adults has been achieved. Occipito-cervical arthrodesis is the recommended treatment option. We advocate a two-stage surgery: the patient is initially fitted with a halo vest then occipitocervical fusion is performed. Surgical treatment should be combined with cardiorespiratory management. The emergency teams should get familiar with this injury since they will be increasingly confronted to it. Early recognition and standard appropriate management is essential to avoid delayed treatment and complications.

Minimally invasive fixation of type B and C interprosthetic femoral fractures

INTRODUCTION Interprosthetic femoral fractures are rare and raise unresolved treatment issues such as the length of the fixation material that best prevents secondary fractures. Awareness of the advantages of locked-plate fixation via a minimally invasive approach remains limited, despite the potential of this method for improving success rates. HYPOTHESIS Femur-spanning (from the trochanters to the condyles) locked-plate fixation via a minimally invasive approach provides high healing rates with no secondary fractures. MATERIALS AND METHODS From January 2004 to May 2011, all eight patients seen for interprosthetic fractures were treated with minimally invasive locked-plate fixation. Mean time since hip arthroplasty was 47.5 months and mean time since knee arthroplasty was 72.6 months. There were 12 standard primary prostheses and four revision prostheses; 11 prostheses were cemented and a single prosthesis showed femoral loosening. Classification about the hip prostheses was Vancouver B in one patient and Vancouver C in seven patients; about the knee prosthesis, the fracture was SoFCOT B in three patients and SOFCOT C in five patients, and a single fracture was SoFCOT D. Minimally invasive locking-plate fixation was performed in all eight patients, with installation on a traction table in seven patients. RESULTS Healing was obtained in all eight patients, after a mean of 14 weeks (range, 12-16 weeks). One patient had malalignment with more than 5° of varus. There were no general or infectious complications. One patient died, 32 months after surgery. The mean Parker-Palmer mobility score decreased from 6.2 pre-operatively to 2.5 at last follow-up. Early construct failure after 3 weeks in one patient required surgical revision. There was no change in implant fixation at last follow-up. No secondary fractures were recorded. DISCUSSION In patients with type B or C interprosthetic fractures, femur-spanning fixation not only avoids complications related to altered bone stock and presence of prosthetic material, but also decreases the risk of secondary fractures by eliminating stress riser zones. The minimally invasive option enhances healing by preserving the fracture haematoma. Thus, healing was obtained consistently in our patients, with no secondary fractures, although the construct failed in one patient. LEVEL OF EVIDENCE Level IV.

Reliability of locked plating in tibial plateau fractures with a medial component.

BACKGROUND Tibial plateau fractures are notoriously difficult to manage, particularly when there is a medial or posteromedial component. We report a retrospective analysis of our experience with consecutive tibial plateau fractures including a medial component that were managed using a single lateral locking plate. HYPOTHESIS Tibial plateau fractures with a medial component can be effectively managed using a single lateral locking plate. MATERIALS AND METHODS From January 2005 to December 2008, 20 patients (ten women and ten men, mean age 47 years) were managed for tibial plateau fractures having a medial component, including five Schatzker IV, five Schatzker V, and ten Schatzker VI. One patient had an open fracture. A single lateral anatomically contoured locking compression plate (LCP™) was used with or without additional isolated screws. Mobilization was started immediately after the procedure, and non-weight-bearing was maintained for at least 6 weeks. RESULTS All patients were followed until healing. A final evaluation was available for 13 patients after a mean of 39.1 months (12-72); five patients were lost to follow-up and two died. Early revision was needed in one patient for 20° malreduction within the fracture site. We recorded one case each of deep vein thrombosis, superficial infection, knee stiffness, and spontaneously regressive common fibular nerve dysfunction. At final evaluation (n=13), mean range of motion was 0°/2°/130° with a mean Lysholm score of 94.1 (73-100) and a mean HSS score of 93.6 (74-99). All previously employed patients returned to work at the same level after a mean of 4.5 months. Mean healing time (n=20) was 10 weeks (6-12). Initially, articular step-offs greater than 2mm were noted in five patients. At healing, no further displacements or aggravation of articular step-offs were recorded. The reductions remained stable over time. At final evaluation (n=13), mean tibiofemoral mechanical angle was 179.7° (176-184) and no patients had evidence of osteoarthritis. DISCUSSION The radiological and clinical outcomes in our patients were satisfactory. A single lateral locked plate ensured stable reduction of tibial plateau fractures with a medial component. Biomechanical studies of these fractures have provided conflicting data on the stability of reduction using single plate systems. However, previously reported clinical outcomes are similar to those found in our study and support the effectiveness of favouring the use of single locking plate fixation. LEVEL OF EVIDENCE Level IV, noncomparative retrospective study.

Locked plating for internal fixation of the adult distal femur: influence of the type of construct and hardware on the clinical and radiological outcomes.

INTRODUCTION Distal femoral fractures are rare and serious. Along with traditional internal fixation, new, dedicated hardware have appeared (distal nails, locked plating). We report the results of a multicenter prospective study of these fractures treated with locked plating. HYPOTHESIS The short-term results are satisfactory and related to the type of construct and the hardware used, with better results for elastic assemblies and titanium implants. MATERIALS AND METHODS From June 2011 to May 2012, 92 patients, mean age 64 years, were included in 12 centres. The fractures were classified as follows: 44 type A, 7 type B, and 41 type C according to the AO classification. Thirteen fractures were open. The plates were uniaxial. The assemblies were elastic in 52 cases, rigid in 26, and unconventional in 14. RESULTS Seventy-six patients underwent a radiological follow-up at 6 months and 66 patients had a clinical result evaluated at 1 year. The mean range of motion was 100° and the mean IKS score was 122. The bone union rate was 87% within 12 weeks. Seven valgus, two varus, ten flexion deformities, and three recurvatum greater than 5° were observed (19.5%). Revisions involved two cases with loss of fixation, five cases of infection, and one case of arthrofibrosis (requiring arthroscopic arthrolysis). Secondary bone grafting was carried out in seven cases (four successfully). No influence of the type of assembly or the hardware used was demonstrated. DISCUSSION The results remain modest, underscoring the severity of these fractures. Neither the type of construct nor the hardware used influenced the radiological and clinical outcomes. The hypothesis was not confirmed. LEVEL OF EVIDENCE Level IV prospective, non-comparative study.