Metal-on-metal surface hip arthroplasties. Is annual monitoring of blood metal levels necessary?

INTRODUCTION

Blood cobalt (Co) and chromium (Cr) ion levels have been used as surveillance tools for adverse reaction to metal debris in metal-on-metal (MoM) hip arthroplasty. The aim of our study was to present serial 7-13 year blood Co and Cr levels in a cohort of MoM total hip arthroplasties in asymptomatic patients.

MATERIAL AND METHODS

A total of 52 MoM surface total hip arthroplasties were included in this study with data collected prospectively. Annual follow-up with blood Co and Cr measurements was performed. Revision surgery was necessary for 16 patients and therefore they dropped out of the study. The metal ion levels were analyzed separately in 31 asymptomatic patients.

RESULTS

High Cr or Co levels were not found continuously in any of the asymptomatic patients. The median Cr in blood was maintained between 1.3 and 5.4μg/L and that of Co between 0.5 and 1.2μg/L. After 7 years, there was no significant change in Co and Cr values.

CONCLUSION

In the medium term and in asymptomatic patients, the metallic blood levels remained unchanged; therefore, it does not seem appropriate to repeat these tests on a permanent basis in annual controls.

Navigated versus conventional total knee arthroplasty: A prospective study at three years follow-up

OBJECTIVE

Computer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA.

MATERIAL AND METHOD

In a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment.

RESULTS

All clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group. The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (P<.01).

CONCLUSIONS

The use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA.

Fever, Malaise, and Dyspnea in a Diabetic Heart Transplant Patient: A Case Report

Patients with solid-organ transplants usually present at the emergency department with nonspecific symptoms. The physician should consider a great variety of syndromes and diseases, given the greater risk that solid-organ transplant patients carry because of immunosuppression and transplant-related conditions. Myocardial infarction caused by cardiac allograft vasculopathy must be always suspected and ruled out, even when initial symptoms do not orientate in that direction. We present a case that conjugates signs that can be present in different pathologies. It shows that fever is not always related to infection or rejection but could also appear in acute cardiac allograft vasculopathy. It emphasizes the need of a multi-disciplinary team led by a heart transplant specialist when dealing with this sort of clinical case.

[Vascular complications after pelvic rami fracture]

The case is presented of a 78 year-old patient who suffered a right ileo- and ischiopubic rami fracture after a casual fall. A few hours later, she presented with sudden abdominal pain and hypotension. Imaging test showed extraperitoneal hemorrhage with active bleeding and hemodynamic compromise. The progressive worsening, with anemia and hemodynamic instability, required her being sent to the reference hospital for selective embolization of the bleeding point. After embolization, the patient́s situation stabilized, and she was then able to sit down one week later. The fracture consolidated 3 months later. Although low-energy pelvic fractures by lateral compression do not usually present with complications, sometimes they require a strict control due to the potential risk of vascular injuries.

[Does the medial-lateral stability of total knee replacements have an effect on short-term clinical outcomes? One-year results of a multicentre study with computer assisted surgery]

OBJECTIVE

To evaluate the influence of the medial-lateral stability of the joint on the short-term clinical outcomes after performing navigation in total knee replacement.

MATERIAL AND METHODS

A multicentre prospective study was conducted on 111 consecutive total knee replacements performed with computer assisted surgery. The study included the evaluation of KSS, WOMAC, and SF-12 preoperatively, and at 3 and 12 months of follow-up, and correlation with stability data obtained during surgery, in extension and at 20° and 90° of flexion.

RESULTS

No differences were found in WOMAC, KSS and SF-12 relative to coronal stability during surgery.

CONCLUSIONS

Variations in coronal stability were shown to have no influence on the short-term clinical results of navigated total knee replacement.

[Minimally invasive surgery versus conventional surgery. A review of the scientific evidence]

The concept that small incisions lead to a better outcome in many procedures has extended into most surgical areas, orthopaedic surgery among them. However, in some cases there is not enough scientific evidence to recommend these procedures. This article attempts to provide an updated review of the works published with sufficient scientific evidence on the advantages of minimally invasive surgery (MIS) compared to conventional access approaches. The published articles, meta-analyses and systematic literature reviews with level I or II evidence are reviewed in topographic order. Wherever possible, the information available on the costs-benefits of this type of surgery is also reviewed.

Navigation in total knee arthroplasty. A multicenter study

We carried out a multicentre study to compare the postoperative femorotibial radiographic axis in two total knee replacement groups; one using manual instrumentation and the other using navigation. In the latter group, three navigation systems were used: Stryker, Orthopilot and Navitrack. The prior circumstances of patients in terms of age, weight, aetiology, epicondylar perimeter, patellar tendon length and knee deformity was similar in both groups. The duration of the operation was longer in the group with navigation (16.7 min). A normal femorotibial axis was more frequently obtained in the group with a navigator compared to the manual group (48.1% and 30%, respectively). A varus axis was most common in the manual group (42.2 and 26.9%, respectively). When we analysed the final postoperative radiographic axis, taking 180 degrees to be a normal result, we noted that cases where manual instrumentation was used deviated by 1.19 degrees more than those carried out with navigation, with this difference being statistically significant (P<0.001). No significant differences were found in the final angle of the extremity with the different navigation systems. The navigation systems used in this study improve the frontal angle of the arthroplasty.

Reverse oblique intertrochanteric femoral fractures treated with the gamma nail

We studied 47 reverse oblique intertrochanteric femoral fractures that were treated with gamma nails between 1992 and 2000. Fracture reduction was satisfactory in 38 patients (81%), the hip screw position was correct in 42 (89%) and there were no peri-operative complications. However, in three patients the nail displaced, resulting in non-union in one and protrusion into the acetabulum in another. A logistical regression analysis of our series showed that an incorrect position of the hip screw in the femoral head was the only predictor for complications. Thus, we consider that the gamma nail is a good option for the treatment of these complex fractures.

Behavior of the femoral stem in the Bihapro hip prosthesis

This study evaluated the hydroxyapatite-coated femoral stem of the Bihapro hip prosthesis (Biomet Ltd, Bridgend, United Kingdom) using radiography, TC-99 scintigraphy, and bone densitometry. Thirty stems with >2 years of follow-up (mean: 31 months) were evaluated. No loosening or changes in the position of the implant were seen, and the mean subsidence was 2.2 mm. Radiography revealed a densification in the metaphyseal zone with reconstruction of the trabecular lines in 21 cases, while in 22 patients, radiolucent lines in the distal area of the femoral component were observed. Scintigraphy showed a diaphyseal normo-captation in 19 cases and a hypercaptation <1.4 with a mean index of 1.1 in 10 patients. Metaphyseal hypercaptation >1.4 was seen in 24 patients. Bone densitometry revealed increased density in the metaphyseal zones in 29 patients with a periprosthetic/normal bone quotient of 1.4.

Loosening of threaded acetabular cups in arthroplasty of the hip. The association with different types of coxarthrosis

Seventy-nine patients underwent hip arthroplasty using a threaded acetabular cup during 1988 and 1989. Out of 71 cups implanted for coxarthrosis, radiographs of 62 have been reviewed at a mean follow up of 69 months. The survival rate at 5.5 years was 77.5%. The mean age at operation was 61 years. Loosening of the cup occurred in 7 cases with pain on walking; 5 had a revision operation. In another 28 patients, radiolucent lines greater than 1 mm were found around the cup and 7 of these were unstable. The previous coxarthrosis was classified as atrophic with 5 loose cups, normotrophic with 2 loose cups and hypertrophic with no loosening. This difference between loosening in the atrophic and hypertrophic types of preexisting coxarthrosis was statistically significant. Radiolucent lines were present in 61% of the atrophic cases, 53.4% of the normotrophic and 25% of the hypertrophic, which was also significant. If the cases of loosening are added to those with radiolucent lines, the types of coxarthrosis show highly significant differences. Threaded cups had a high percentage of failure which was greater in cases with atrophic coxarthrosis.

Patellar complications after total knee arthroplasty

One hundred total knee arthroplasties implanted between 1989 and 1993 in 70 women and 30 men (average age 67.4 years) have been retrospectively reviewed. Six late patellar complications occurred: two fractures, two subluxations, one dislocation and one loosening. Four had a further operation. The patient's age, type of implant, lateral patellar release, thickness of the implant and the final range of movement were studied. Complications have been more common in men (8.7%) than women (5.2%) with a statistically significant difference (p < 0.05). This may be because men make a greater functional demand on their arthroplasties. No other factors were relevant.