Gap balancing versus measured resection technique using a mobile-bearing prosthesis in computer-assisted surgery.

Navigation has been developed to help surgeons install implants more accurately and reproducibly; at the same time, this tool is able to record quantitative information such as joint range of motion, laxity and kinematics intra-operatively. As for standard surgery, two strategies are possible to achieve either femoral component rotation or overall prosthetic alignment: a measured gap resection approach, in which bone landmarks are used to guide resections equal to the distal and posterior thickness of the femoral component, or a gap-balancing technique, in which equal collateral ligament tension in flexion and extension is tried to find before as a guide to final bone cuts. The purpose of this paper is to compare the two different methods in a 67 patients group submitted to the same procedure using mobile-bearing (MB) prosthesis in order to analyse the effect of both techniques on joint line maintenance, axial limb restoration and components position. The gap group (GG) consists of 31 patients in whom the arthroplasty was performed using a navigated gap-balancing technique. The measured group (MG) consists of 36 patients in whom a computer-assisted measured resection technique was used. The results of imaging and the number of outliers were not statistically different (P = 0.56) for the mechanical axis and prosthetic positioning between the two groups. The gap technique showed a statistically significant alteration of the post-operative value when compared with the measured resection technique, (P = 0.036). The mean elevation of the joint line was 4.09 mm for the GG and 3.50 mm in the MG.

Comparison between two computer-assisted total knee arthroplasty: gap-balancing versus measured resection technique.

Two surgical strategies are possible in total knee arthroplasty (TKA): a measured resection technique, in which bone landmarks are used to guide resections equal to the distal and posterior thickness of the femoral component, or a gap-balancing approach, in which equal collateral ligament tension in flexion and extension is sought before and as a guide to final bone cuts. In this study performed with computer assisted system, we compared the 2 different methods in 126 patients followed prospectively in order to analyze the effect of both the techniques on joint-line (JL) maintenance, axial limb restoration and components position. The gap technique showed a statistical increase in the post-operative value when compared with the measured resection technique, (P = 0.008). When comparing the two groups regarding to the pre-operative deformity, we have found a statistical difference (P = 0.001) in case of moderate pre-operative deformity (less than 10 degrees), and the measured resection technique showed a slight superiority in preserving a joint line more faithful to the pre-operative. We found an ideal alignment for the mechanical axis (180 degrees ± 3 degrees) (95% of cases). In six cases (5%), the mean post-operative value exceeded (varus or valgus) the ideal value by more than 3 degrees. In the frontal plane, a good alignment was observed for both femoral and tibial components without a significant difference between the two techniques. In the sagittal plane was found more alignment variability due to the different implants used and their ideal starting slope, from 7 degrees to 3 degrees. Finally, the surgeon can use the approach with which he has more confidence; however, as the measured resection technique causes less reduction in the post-operative joint-line position, in case of shortening of patellar tendon or patella infera, this technique is preferable.

Chronic recurrent multifocal and aspecific osteomyelitis: a case report.

Chronic recurrent multifocal and unspecific osteomyelitis (CRMUO) is a severe form of chronic nonbacterial osteomyelitis. Lesions can be found anywhere in the skeleton, in young patients, such as children or adolescents, chronic nonbacterial osteomyelitis often affects the metaphyses of the long bones. Furthermore, other organs like skin, eyes and gastrointestinal tract can also be affected. Because of symptoms and course of disease vary in significant way, a clinical diagnosis is often difficult. The radiographic appearance suggests subacute or chronic osteomyelitis. CRMUO may mimic acute hematogenous osteomyelitis, but bacterial culture are usually negative and nonspecific histopathological and laboratory findings are present. This kind of osteomyelitis is often diagnosed by exclusion of the two main differential diagnoses-bacterial infections and tumor-by assessing for a characteristic course and the findings by conventional radiography, if necessary supplemented by scintigraphy and magnetic resonance imaging (MRI). The MRI appearance of CRMUO lesions in tubular bones and the spine is often rather characteristic and can support the diagnosis. It is important to diagnose CRMUO to avoid unnecessary diagnostic procedures or therapy, and initiate an appropriate one. We present a case report of a 44-year-old woman diagnosed with CRMUO involving both femurs.

Trabecular metal patella in total knee arthroplasty with patella bone deficiency.

This study evaluates results following patellar resurfacing using trabecular metal (TM) patella in marked deficiency or weakness of patellar bone that precludes patellar resurfacing with a standard cemented patellar button. Ten consecutive patients undergoing primary (3 cases) or revision (7 cases) total knee arthroplasty with patella augmentation were evaluated at a mean follow-up of 45 months (range 18-65). Nine patients had marked patellar bone deficiency and one had had previous patellectomy. No intra-operative complications occurred. There was no displacement of the patellar component and no patellar fractures when at least 50% of bone contact was possible. We observed loosening of the patella augmentation 17 months after the index procedure only in the case of previous patellectomy. When bone was present the fixation appeared excellent by radiographic evaluation already at 3 to 6 months after surgery; afterward bone contact was uniform in the peripheral regions in both lateral and Merchant radiographic views without signs of loosening. Finally, the mean Knee Society scores improved in all patients.

Preliminary experience with electromagnetic navigation system in TKA.

Accuracy of implant positioning and precise reconstruction of leg alignment offers the best way to achieve good long-term results in total knee arthroplasty. Computer instrumentation was developed to improve the final position of the component and restore the mechanical axis. Current navigation systems use either optical or electromagnetic tracking. The advantage of the Electromagnetic (EM) navigation system is that no line-of-sight issues are present. However, special iron-free instruments are required. This report analyzes the postoperative radiological results of 32 knees treated using an EM system. All the measurements were recorded using software able to subtend angles automatically by five physicians, three radiologist and two orthopedic residents not involved with the surgery. Each radiograph was measured three times, in random order, and at delayed intervals. We found an ideal alignment for the mechanical axis (180+/-3 degrees ) in 30 out of 32 cases, whereas all the patients achieved a value of 90 degrees +/-3 degrees for both femoral and tibial frontal component angles. An apparently over-corrected implant position for the sagittal femoral component was reported, with a mean value of 11.2 degrees +/-3.6. The mean position of the tibial component was 90.6 degrees +/-2.8; just four measurements were outside of the +/-3 degrees of the desired value. EM is safe and there were no complications related to this system. An almost perfect correlation was found between the mechanical axis value of the EM navigation system (179.8 degrees +/-1.8) and the median value of the all reviewers (180.3 degrees +/-1.9) with a difference of 0.5 degrees .

Escharotomies, fasciotomies and carpal tunnel release in burn patients--review of the literature and presentation of an algorithm for surgical decision making.

Escharotomies are usually performed in patients with circumferential third degree burns of the extremities or anterior trunk. Fasciotomies are recommended for patients who sustained high voltage (or associated crush) injuries, with entrance or exit wounds in one or more extremities. Carpal tunnel release is practiced routinely in some services for cases of electrical injury. We have reviewed the literature which provides relatively little information as to when should these procedures actually be performed and what would happen if they were not done. We present a series of patients treated at our institution when an algorithm was used for surgical decision making as to when (or not) to operate (perform an escharotomy, a fasciotomy or a carpal tunnel release), based on clinical signs and monitoring alternatives, using the oximeter and the Doppler flowmeter. 13 938 burn patients were treated at our institution during the year of 2005. Of these, 571, with an average of 22.3 % TBSA, were treated as inpatients. Of these, 58 (10.3 %) had circumferential or electrical burns of one or more extremities. Patients were monitored hourly from admission and decision to operate was based on clinical signs and in absent or below 90 % oximetry, regardless of Doppler flow signs. 68 % were males, 6 (11.3 %) patients had immediate escharotomies, while 4 (7.5 %) had immediate fasciotomies. 2 of these patients were operated regardless of positive Doppler sign but no oximetry. All patients recovered oximetry over 90 % immediately after the operations. 3 patients had negative Doppler sign but oximetry > 90 % and were not operated. 3 patients had carpal tunnel releases based on oximetry < 90 % and symptoms of compression of the median nerve. Patients who were not operated fared well with no signs or symptoms of impairment of circulation or nerve damage up to their 3 and 6 months reevaluations.

Learning curve of microvascular venous anastomosis: a never ending struggle?

In this study, a simple protocol based on the rat femoral venous anastomosis was established to provide a quantitative representation of the progress. The learning curve is based on the patency rate in each consecutive group of five anastomoses. Two groups of surgeons were observed. The inexperienced group encountered a tough time in the first 25 anastomoses. However, the progress was fast and is represented by the steep slope of the curve. A plateau was reached whereby the avearge patency rate matches that of the experienced group. As expected, there was no learning curve for the experienced group. Despite every effort to attempt to maintain a perfect 100% patency on this model, the best achievable patency was only 88%. The results and its implication are discussed.

Chemotactic mediator requirements in lung injury following skin burns in rats.

Partial-thickness skin burns have been shown to induce neutrophil-dependent microvascular injury both locally (skin) and systemically (lung). In the present study, interventional measures to block inflammatory chemoattractants were employed to define the pathophysiologic role of these mediators in the development of secondary lung injury following thermal injury of skin. Rats were treated with blocking antibodies to either C5a or to the alpha-chemokines, keratinocyte-derived cytokine (KC), or macrophage inflammatory protein-2 (MIP-2). To study the role of platelet activating factor, a receptor antagonist (PAF-Ra) was utilized. The development of lung vascular injury following thermal injury to skin was significantly attenuated by treatment with anti-C5a (84%), anti-KC (67%), and anti-MIP-2 (77%), but treatment with PAF-Ra had no protective effects. Protective interventions were paralleled by significant reductions in the tissue buildup of myeloperoxidase. When bronchoalveolar lavage fluids from thermally injured rats were evaluated, elevations in TNF;ZA and IL-1 were found and were determined to be C5a-dependent (but unaffected by treatment with PAF-Ra). These studies indicate that lung tissue injury after thermal skin burns is dependent on chemotactic mediators. The data also suggest that lung expression of TNFalpha and IL-1 after thermal injury of skin is C5a-dependent.

Role of chemotactic factors in neutrophil activation after thermal injury in rats.

Acute thermal trauma is well known to produce evidence of a "systemic inflammatory response" in vivo, as manifested by evidence of complement activation, appearance in plasma of a variety of inflammatory factors, and development of multi-organ injury. The current studies were focused on acute thermal injury of rat skin and factors responsible for accompanying activation of blood neutrophils. Acute thermal injury of rat skin resulted in a time-dependent loss of L-selectin and up-regulation of Mac-1 (CD11b/CD18) on blood neutrophils, with no changes in LFA-1 (CD11a/CD18). The loss of L-selectin was prevented by blockade of C5a but not by blockade of the alpha-chemokine, macrophage inflammatory protein-2 (MIP-2). C5a, the alpha chemokines, MIP-2 and keratinocyte-derived cytokine (KC), and platelet activating factor (PAF) contributed to up-regulation of blood neutrophil Mac-1. Blocking interventions against these mediators also blunted the degree of neutropenia developing after thermal trauma. These data suggest that activation of blood neutrophils after thermal trauma is related to the role of several chemotactic mediators. These studies may provide clues regarding factors responsible for development of the "systemic inflammatory response syndrome" after thermal injury in the experimental model employed.

[The incidence of Raynaud's phenomenon in 1920 residents in Milan]. / Incidenza del fenomeno di Raynaud in 1920 residenti in Milano.

We use the term Raynaud Phenomenon (RP) to define episodic digital ischemia with colour changes involving the digits of the hands and feet, induced by cold or emotional stresses. Surprisingly little information is available concerning the incidence of RP in the general population. In Italy, studies of this purpose have never been carried out and the few investigations, we find in literature, are discording, showing an incidence between 0.83% and 27%. The interest in knowing the incidence of RP is, beside the usual reason which get to an epidemiological study, RP indeed may be associated with severe and disabling clinical conditions as connective tissue diseases. The RP may be the initial complaint on an otherwise silent systemic illness and may even influence the course of these clinical conditions, assuming the role of prognostic index. It seemed useful for us to investigate on a model of population resident in our city the incidence of RP and the frequency of the idiopathic and secondaries forms. We have prepared a set of questions which was distributed to some students attending the IV year of the School of Medicine and to specialized doctors. The students randomly interviewed as many people as they could, while the doctors had to fill the questionnaire for companions of patients coming to three different Sanitary Units in Milan. All those subjects that at first instance were diagnosed as RP were sent to our ambulatory where more experienced doctors provided to collect a precise history.(ABSTRACT TRUNCATED AT 250 WORDS)

Sun tanning-related burns--a 3-year experience.

A retrospective study has analyzed 562 sun-related burns out of 19,643 patients treated at our institution from 1 March 1988 to 28 February 1991. These patients were analysed according to sex, age, burn area, mode and length of treatment and outcome. Females, mainly adults, represented 60.8 per cent of all patients presenting burned due to sun bathing. There is a marked seasonal incidence, proportionally constant throughout these 3 years. The main causes of injury were sun only (36.7 per cent), sun plus fig leaf 'tea' tanning lotion (17.7 per cent) and lemon juice (17.7 per cent). Healing to normal skin appearance was achieved in 99.1 per cent, 0.7 per cent healed with scarring and one patient died due to massive sepsis. The effect of sunlight on skin and the process of 'sunburn' when using homemade plant-derived tanning lotions containing substances which can induce a photodermatitis reaction is also discussed.

Two years in burn care, an analysis of 12,423 cases.

This is a retrospective study analysing 12,423 patients treated at our institution from 1 July 1988 to 30 June 1990. Burn incidence and mode of treatment were classified according to age and sex, as well as causative agent, place of the accident, length of treatment and outcome. 96.6 per cent of the patients were surgically treated, about 41 per cent of the patients were under 14 years of age. The most frequent cause of injury was related to meal preparation, with more than two-thirds of the accidents occurring at home. Only large or complicated burns (1094-8.8 per cent) were admitted, with 49 deaths occurring during this period. We conclude that children and younger adults are at greater risk of being burned and preventative measures should be oriented towards the prevention of such accidents.

Estudo comparativo da eficácia de cinco medicamentos tópicos no tratamento de queimaduras / Efficacy of five topical agents in burn treatment: a comparative study

Os autores realizaram um estudo comparativo de cinco preparados para uso tópico no tratamento de queimaduras. Foram tratadas 125 (cento e vinte e cinco) pacientes, divididos aleatoriamente em cinco grupos de 25 (vinte e cinco) pacientes cada. Os medicamentos empregados foram o merbromino a 2(pôr cento), salicilato de sódio, sulfadiazinato de zinco e a combinaçäo de colagenase com clorafenicol. No grupo IV foi feita uma associaçäo do salicilato de sódio e sulfadiazinato de zinco. A análise estatística dos resultados mostrou näo haver diferença significativa entre os diversos grupos, quando se toma em consideraçäo o tempo necessário para a completa epitelizaçäo das lesÆes

Electric burns of the lip.

Young children, usually aged between 1 and 3 years, are frequent victims of electric burns of the lip caused by contact with an electric plug or extension cord. In this article, the authors classify the various types of lesions in 19 cases of electric burns of the lip and discuss surgical treatment approaches.

The treatment of prominent ears: a 25-year survey of the island technique.

The authors report on a 25-year retrospective study of 488 cases of prominent (protruding) ears corrected by the island technique of Pitanguy.