Aim

Recent studies have indicated that the presence of P. acnes in the skin of the shoulder and around the acromion is higher than other body regions like the knee or the hip. The aim of this study was to estimate the presence of P. acnes in a real set of primary shoulder arthroplasty, after skin preparation with chlorhexidine and administration of empirical antibiotic therapy.

The purpose of this study was to compare the diagnostic accuracy for the detection of infection between the culture of fluid obtained by sonication (SFC) and the culture of peri-implant tissues (PITC) in patients with early and delayed implant failure, and those with unsuspected and suspected septic failure. It was hypothesised that SFC increases the diagnostic accuracy for infection in delayed, but not early, implant failure, and in unsuspected septic failure. The diagnostic accuracy for infection of all consecutive implants (hardware or prostheses) that were removed for failure was compared between SFC and PITC. This prospective study included 317 patients with a mean age of 62.7 years (9 to 97). The sensitivity for detection of infection using SFC was higher than using PITC in an overall comparison (89.9% versus 67%, respectively; p < 0.001), in unsuspected septic failure (100% versus 48.5%, respectively; p < 0.001), and in delayed implant failure (88% versus 58%, respectively; p < 0.001). PITC sensitivity dropped significantly in unsuspected compared with suspected septic failure (p = 0.007), and in delayed compared with early failure (p = 0.013). There were no differences in specificity.

Sonication is mainly recommended when there is implant failure with no clear signs of infection and in patients with delayed implant failure. In early failure, SFC is not superior to PITC for the diagnosis of infection and, therefore, is not recommended as a routine diagnostic test in these patients.

Cite this article: Bone Joint J 2013;95-B:244–9.

Patients with infected arthroplasties are normally treated with a two-stage exchange procedure using polymethylmethacrylate bone cement spacers impregnated with antibiotics. However, spacers may act as a foreign body to which micro-organisms may adhere and grow. In this study it was hypothesised that subclinical infection may be diagnosed with sonication of the surface biofilm of the spacer. The aims were to assess the presence of subclinical infection through sonication of the spacer at the time of a second-stage procedure, and to determine the relationship between subclinical infection and the clinical outcome. Of 55 patients studied, 11 (20%) were diagnosed with subclinical infection. At a mean follow-up of 12 months (interquartile range 6 to 18), clinical failure was found in 18 (32.7%) patients. Of the patients previously diagnosed with subclinical infection, 63% (7 of 11) had failed compared with 25% (11 of 44) of those without subclinical infection (odds ratio 5.25, 95% confidence interval 1.29 to 21.4, p = 0.021). Sonication of the biofilm of the surface of the spacer is useful in order to exclude subclinical infection and therefore contributes to improving the outcome after two-stage procedures.

Introduction: Life expectancy is increasing, this leads to a major number of hip fracture and its subsequent complications and costs.

Proximal femur fracture is not only a medical problem but also a social handicap.

Our objective is to see, by means of a prospective observational study, how the function varies after hip fracture and which are the most influencing factors in order to get maximum benefits of resources for this patology.

Materials and Methods: 262 patients had been hospitalized suffering hip fracture in our centre between june 2006 and December 2007.107 of them were included in the study, the others were excluded for different reasons: cognitive impairment (based on Folstein test), previous hip fracture or pathologic fractures.

86 female and 21 male. Mean age 74 years (65–93).44 suffering subcapital fracture and 63 pertrochanteric fracture. 76 patients underwent gamma nail or canulated screws and 31 hemi or total hip replacement. Mean surgery delay 3 days (1–14) At the moment of hospital registration we also determined marital status, familiar support, living at home or institution, morbidity pre- fracture (according to Charlson index), level of dependence (Barthel index), mental status (Folstein Mini Mental State Examination)quality of life perceived (short form 36 (SF-36)) and depression symptoms (Geriatric Depression Scale 15 (GDS 15)).

At three months post discharge we determined again all the test mentioned before and also recorded the functional level (Harris test), which haven’t been passed preoperatively because it includes a part of physical evaluation, not possible to do in a fractured leg.

Statistics: Analysis of Variance for repeated measures, Spearman correlation coefficient, level significance 0.05

Results: Most part of patients came from their own houses (87,6%), where only returned 23% of them at hospital discharge. In the control visit al 3 months most of them had returned at home (79%)

There were no significant differences between functional outcome al three months and delay of the surgery (p 0.76) or the type of surgery (artroplasty vs osteosintesis) (p0.308).

There was a negative correlation (rho-spearman −0.656)between depression and functional outcome, the more depressed a patient is the worse functional outcome he has (p 0.002)

There was a positive correlation (rho-spearman 0.605) between function (Harris test) and dependency (Barthel index).Patients less independent pre fracture are the ones with low function at three months. (p 0.000)

Discussion: There are a lot of patients needing nursing or social facilities at hospital discharge with the high costs that this supposes. We have seen that depressed people at hospital income are going functionally worse than non depressed and consequently are more dependent persons. Maybe early diagnosis ant treatment of depression will help to get maximum results of rehabilitation procedure.

Background: The presence of bacteria forming biofilms or prior antimicrobial use has been shown to reduce the sensitivity of the standard technique (PT cultures) in patients with infection of orthopedic implants. Culturing fluid resulting from sonication (FRS) of prosthesis could improve the microbiologic diagnosis.

Objective: To analyze the diagnostic validity of culturing FRS of different orthopedic implants and PT culture

Methods: Between Jan 2007 and Apr 2008, patients undergoing knee or hip prosthesis removal, and those with ostheosyntesis or spinal instrumentation removal, were prospectively included (44 hip prosthesis, 63 knee prosthesis, 91 osteosynthesis and 14 spinal instrumentations). 5 PT specimens were collected for culture. Removed implants were sonicated during 5 min. (40Hz). Both, PT and FRS, were inoculated in aerobic agar (Chocolate Polyvitex), anaerobic agar (Schaedler + 5% blood) and in thioglycolat, for 7 days. Positive culture cut-off was defined as growing of > 5 CFU. Clinical diagnosis of prosthetic-joint infection was made as commonly accepted. Previous antimicrobial therapy was assessed. Diagnostic validity was calculated for both culturing methods. Sensitivity of methods was compared by Chi-square test (SPSS 15.0).

Results: 212 cases were included. Diagnostic of infection was made in 17 hip prosthesis (THA), 20 knee prosthesis (TKA), 24 osteosynthesis (OS) and 6 spinal fusions (SI).

Tissue culture was positive in 9 THA, 11 TKA 18 OS and 4 SI. Sonication culture was positive in 14 THA, 18TKA, 23 Os and 6 SI.

Tissue culture: Sensibility: THA53%, TKA 55%, OS 75% and SI 66%. Specificity: THA 96%, TKA 100%, OS 96%, SI 100%

Sonications: Sensibility: THA 82%, TKA 90%, OS 95% and SI 100%. Specificity: THA 96%, TKA 100%, OS 92%, SI 100%

Statistical differences favoring sonication were found in sensitivity in knee arthroplasty and osteosynthesis implants. 6 patients received antibiotics for > 7 days before implant was removed. Sonication culture was positive in 4 of them whereas only one standard culture yielded positive.

Conclusions: FRS cultures are more sensitive than PT cultures. Sensitivity of the method depends on which device is evaluated. Sonication also improves sensitivity of culture after preoperative antimicrobial therapy.

Background and goal of study: Although a great percentage of the total postoperative bleeding corresponds to a hidden blood loss in the tissues and joint, visible blood from the drainage is considered the gold standard for monitoring blood loss after a knee arthroplasty. Only one study was not able to find a consistent relationship between the total blood loss and postoperative drained blood. The aim of our study was to assess the usefulness of a postoperative drainage as a monitor of bleeding following a knee arthroplasty.

Material and methods: Fifty patients undergoing unilateral arthroplasty from March to November 2004, were prospectively followed until the fourth postoperative day. Drained red blood cells(RBC) loss was assessed by multiplying the drained blood volume by an haematocrit (Hct) of 30% from a pilot study. Total RBC loss and hidden RBC loss from each patient were calculated. Regression analysis was performed to assess the relationship between the total RBC loss and drained RBC loss.

Results and discussions: The average age of the fifty ASA 2 patients was 72 +− 7 years. Nearly all the procedures were performed under intradural anaesthesia. Cemented technique and tourniquet were used in all cases. The mean total RBC loss was 615 +−197ml. The mean drained RBC loss was 206+− 113ml, and mean hidden RBC loss was 414 +−194ml. Thus the hidden loss was 67% of the total blood loss. Regression analysis shown a poor correlation coefficient between the total RBC loss and drained RBC loss (r= 0.31, p< 0.03).

Introduction: Defects in rotational alignment of the femoral component in total knee replacements (TKR) may cause poor alignment of the extensor apparatus. There are numerous references concerning the correct alignment of the femoral component of a prosthesis: transepicondylar axis, anteroposterior axis, and posterior condylar axis.

Materials and methods: Computer-assisted measurement of the relative differences between the transepicondylar axis, anteroposterior axis and posterior condylar axis in 38 TKR patients, excluding those with varus or valgus deformity greater than 15 degrees.

Results: The difference between the anteroposterior axis and the transepicondylar axis was 3.13 degrees of external rotation in the former.

Between the posterior condylar axis and the transepicondylar axis it was 1.18 degrees of internal rotation in the former.

Between the anteroposterior axis and the posterior condylar axis it was 5.51 degrees of external rotation of the former.

Conclusions: Probably the transepicondylar axis is the best landmark to enable reproducing the biomechanics of the knee in a patient bearing a prosthesis, although it is often difficult to reproduce it precisely. Several studies have noted errors among observers that are too great to make us feel certain that we are doing the best thing.

Although it is accepted that the perpendicular to the anteroposterior axis is reliable and corresponds to 4° of external rotation in relation to the posterior condylar axis, we have observed significant differences from one patient to another.

It would seem preferable to use a combination of the different axes, which we can do with a surgical browser.

Introduction: Meniscal extrusion is defined as the situation in which the meniscus is partially or totally luxated from the tibial plateau. The aim of this work is to ascertain the prevalence of meniscal extrusion in non arthritic patients and to define those factors related to it. Special attention was given to the fact of anatomic variations in the menisci attachments.

Methods: The knee MRI of 100 patients that were operated on arthroscopically in our institution was prospectively studied. Seventy-two males and 28 females, average age of 36.6 years (range between 13 and 64), entered in the study. There were 43 right-knees and 57 left-knees. The average weight of the patients was 77 kg (range 44 to 135).

Results: With respect to the medial meniscus 68.9% of the cases showed some degree of extrusion, averaging at 28% of the meniscal size (ranging from 10% to 60%). In the case of the lateral meniscus extrusion averaging 15% (ranging from 10% to 40%) was seen in 18.8% of the cases.

In this series the posterior types of anterior medial meniscus insertion were the most frequently found (69.5%).

Medial meniscal extrusion was significatively correlated to the presence of a chondral lesion (p = 0.008) and to anterior medial meniscus insertion (p = 0.001). No statistical significant relationship to the rest of parameters studied was encountered. None of the parameters studied were related to lateral meniscus extrusion

Discusion: Meniscal extrusion is frequent in our series and, the hypothesis that those patients who have an anterior variant of the anterior horn insertion of the medial meniscus tend to show greater extrusion is confirmed.

Introduction: The correct position of the knee arthroplasty components is associated with a better result of the prosthesis.

In the tibial component, both intramedullar and extramedullar instrumentations have been used for its fiability, but in the femoral component intramedullar guides are more precise than extramedullar ones.

The use of the intramedullar guide for the femoral component is not always possible, because a significant deformity of the femoral shaft or when a intramedullar device has been implanted in the femur.

We have studied the alineation of the components of computer assisted total knee arthroplasties in a group of patients with femoral deformities or implants.

Material and methods: We have used the surgical navigator Stryker-Howmedica for the implantation of a knee arthroplasty in a group of 10 patients in which a endomedullar femoral guide can not be used for femoral shaft severe deformities (6 cases): Paget disease (1 case), previous femoral osteomyelitis (2 cases) or previous femoral fractures (3 cases), or a shaft device was in the femoral shaft (4 cases): long hip femoral stem (3 cases) or a femoral nail (1 case) .

We have studied the alineation of femoral and tibial components with a whole-leg X-ray and Computer Tomography.

Results: All the femoral and tibial components have been implanted in a good position (90 +/– 2 degrees in the A-P plane and a femorotibial axe 180 +/– 3 degrees. The alineation in the sagital and axial planes have been inside the desired values in all cases also.

Discussion: It is generally accepted than intramedullary guides for the femoral component is the gold standard in arthroplasty of the knee.

In the last years, the development of computer assisted systems has allowed to obtain femoral and tibial cuts referred to the mechanical axes of the bone, without using mechanical guides for the alineation.

In some studies these navigation systems are better than mechanical instruments in terms of alineation of the components in cases without great deformities.

In this study, with some cases with severe femoral shaft deformities or with some intramedullary devices that does not allow the use of intramedullary femoral guides, we think that the indication to use a surgical navigator should be nearly absolute.