Adverse reaction to metal debris after small-head diameter metal-on-metal total hip arthroplasty: an increasing concern.

INTRODUCTION:: Failures due to adverse reaction to metal debris (ARMD) have become an area of common focus among surgeons performing hip replacements. Several authors have reported data on the prevalence of these masses, in both symptomatic and asymptomatic patients after either large-diameter head metal-on-metal (MoM) total hip arthroplasty (THA) or hip resurfacing arthroplasty, with a large variability of rate. To our knowledge, few data are reported on the association of this lesion with the use of small-head diameter MoM. METHODS:: 15 hips that were revised for ARMD in small-head MoM THA were included in this study. We focused our attention on the difficulties of diagnosis and treatment and also on the histologic aspects of the harvested pathologic tissue. RESULTS:: The histological examination of our cases showed a presence of lymphocytic infiltrate suggesting a delayed hypersensitivity reaction to the metal of type IV (ALVAL), but different from each other in term of the prevalence of the cellular component. Osteolysis and severe soft tissue damage were also observed. Revision resulted in remission of the lesion and successful implant. CONCLUSIONS:: Our observation suggests that the evidence of ARMD should be considered even in case of small-head MoM arthroplasty and therefore these patients should be followed scrupulously with 2nd level diagnostic tools such as magnetic resonance imaging with metal artifact reduction sequence (MARS-MRI) and metal ion levels at least once. Further investigations are necessary to establish the real prevalence of this phenomenon in the whole population of small-head MoM THAs.

Outcome of distal tibia physeal fractures: a review of cases as related to risk factors.

INTRODUCTION: The physeal fractures represent the 20-30% of all fractures of the child. The distal tibial physis is the third most frequently injured. The most important complication is the premature physeal closure (PPC). Aim of this study is to evaluate risk factors that can influence the outcome like fracture pattern, fracture displacement, mechanism of injury and treatment method. MATERIAL AND METHODS: The records of 46 patients treated for distal tibia physeal fractures between 2003 and 2013 were reviewed. Initial injury radiographs were categorized according to Salter-Harris and Dias-Tachdjian classifications and the initial and post-treatment fracture displacementwas measured. Any complex fractures had preoperative CT for additional assessment. Three different types of treatment were compared: closed reduction and casting versus closed reduction and percutaneous pinning versus ORIF. RESULTS: Therewas significantly less residual displacement in patients who had ORIF versus those who had closed reduction and percutaneous Kirschner wires or plaster only. In fractures with an intact fibula, we found significantly less initial and residual displacement. The Dias-Tachdjian classification is significantly correlated with the displacement. Patients studied with CT show a less degree of post reduction displacement. At the final follow-up we found only one PPC as complication. CONCLUSION: The physeal fractures are very common in children and the main goal is to avoid any complications. It is clear that the development of complications after distal tibial fractures is due to multiple contributing factors like skeletal maturity, severity of injury, fracture type, degree of comminution and displacement aswell as adequacy of reduction. A premature physeal closure is the most common complication. The fibula fracture can play an important role in initial displacement. The presence of an intact fibula and a good anatomical reduction have a significant positive influence on fracture outcome.