Tore Dalén

Hydroxyapatite coating versus cemented fixation of the tibial component in total knee arthroplasty

Fifty-three consecutive patients (57 knees; mean age, 69 years) entered a prospective randomized study to compare the fixation of hydroxyapatite (HA)-coated (29 knees) with cemented (28 knees) tibial components in the Tricon II total knee arthroplasty. The quality of the fixation during 5 years postoperatively was evaluated with radiostereometric analysis (RSA). Three HA-coated implants were revised: 2 owing to infection, and 1 owing to early delamination of the coating and clinical loosening. Eight patients (9 knees) died, 1 patient sustained a stroke, and 1 patient refused investigations after 1 year. In the 40 patients (19 HA-coated, 21 cemented) remaining at 5 years, the magnitude of the micromotion between the HA-coated and cemented groups did not differ. The HA-coated implants displayed most of the migration within the initial 3 months then stabilized, whereas the cemented implants showed an initially lower, but over time continuously increasing migration. Between 1 and 2 years, 4 of 24 HA-coated and 10 of 23 cemented implants migrated >0.2 mm and were categorized unstable, which has been shown to have a prognostic value as regards future aseptic loosening. Progressive radiolucent lines developed in 2 cemented knees, which both were categorized unstable. If HA-coated implants can sustain the forces that threaten the fixation in the early period after implantation, a strong and enduring fixation may be obtained.

Effects of epoetin alfa on blood transfusions and postoperative recovery in orthopaedic surgery: the European Epoetin Alfa Surgery Trial (EEST).

Background and objective: Preoperative epoetin alfa administration decreases transfusion requirements and may reduce transfusion complications, such as postoperative infection due to immune suppression and thus hospitalization time. This study examined the impact of preoperative epoetin alfa administration on postoperative recovery and infection rate. Methods: In an open randomized controlled multicentre trial in patients undergoing orthopaedic surgery, the effects of preoperative administration of epoetin alfa vs. routine care were compared in six countries. Haemoglobin (Hb) values, transfusions, time to ambulation, time to discharge, infections and safety were evaluated in patients with preoperative Hb concentrations 10‐13g dL−1 (on‐treatment population: epoetin n = 460; control n = 235), from study entry until 4‐6 weeks after surgery. Outcome was also compared in patients with and without transfusion. Results: Epoetin‐treated patients had higher Hb values from the day of surgery until discharge (P < 0.001) and lower transfusion rates (12% vs. 46%; P < 0.001). Epoetin treatment delivered no significant effect on postoperative recovery (time to ambulation, time to discharge and infection rate). However, the time to ambulation (3.8 ± 4.0 vs. 3.1 ± 2.2 days; P < 0.001) and the time to discharge (12.9 ± 6.4 vs. 10.2 ± 5.0 days; P < 0.001) was longer in the transfused than in the non‐transfused patients. Side‐effects in both groups were comparable. Conclusions: Epoetin alfa increases perioperative Hb concentration in mild‐to‐moderately anaemic patients and thus reduces transfusion requirements. Patients receiving blood transfusions require a longer hospitalization than non‐transfused patients.

Uncemented HA-coated implant is the optimum fixation for TKA in the young patient.

Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial. We evaluate the results of three different types of fixation of the Profix total knee arthroplasty in a randomized controlled trial of 97 consecutive knees (85 patients) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients. We randomized patients to three different types of fixation of the tibial component: cemented, uncemented (HA coated) with screws, or uncemented (HA coated) without screws. We performed clinical evaluations and radiostereometric analysis at 6 weeks, and 3, 6, 12 and 24 months postoperatively. The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months, but at 2 years we observed no differences. The uncemented implants displayed all migration within the first 3 months. The cemented implants did not stabilize but had continuously increasing migration during the followup. Cementless implants without screws did not migrate more than implants with screws and displayed similar pattern of migration, indicating screws do not improve fixation. Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient. Level of Evidence: Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence.

The Effect of Nonsteroidal Anti-Inflammatory Drug Administration on Acute Phase Fracture-Healing: A Review

BACKGROUND The analgesic efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) is well established, and these agents often form an integral part of posttraumatic pain management. However, potentially deleterious effects of resulting prostaglandin suppression on fracture-healing have been suggested. METHODS A systematic literature review involving searches of electronic databases and online sources was performed to identify articles exploring the influence of NSAIDs on fracture-healing. RESULTS A structured search approach identified 316 papers as potentially relevant to the topic, and these were manually reviewed. The majority described small-scale studies that were retrospective or observational in nature, with limited control of potentially confounding variables, or presented little key information that was not also present in other studies. CONCLUSIONS Although increasing evidence from animal studies suggests that cyclooxygenase-2 (COX-2) inhibition suppresses early fracture-healing, in vivo studies involving human subjects have not provided convincing evidence to substantiate this concern. We found no robust evidence to attest to a significant and appreciable patient detriment resulting from the short-term use of NSAIDs following a fracture. The balance of evidence in the available literature appears to suggest that a short-duration NSAID regimen is a safe and effective supplement to other modes of post-fracture pain control, without a significantly increased risk of sequelae related to disrupted healing.

Mobile bearings do not improve fixation in cemented total knee arthroplasty.

Mobile bearings were introduced to improve wear and knee kinematics. By uncoupling the forces generated at the articulation from the implant-bone interface this would, theoretically, also improve the fixation of the implant to bone. We did this study to evaluate whether mobile bearings improve the fixation of the tibial component to bone. Fifty-two consecutive knees in 47 patients (average age, 72 years; range, 62-84 years) with primary osteoarthrosis were randomized into two groups to receive a cemented total knee arthroplasty with either a fixed-bearing or mobile-bearing tibial component. The quality of fixation was analyzed with radiostereometric analysis for up to 2 years. Mobile bearings did not improve fixation. Both magnitudes and directions of component rotations were similar, and the number of implants with continuous migration was almost identical. Both implant types had a combination of subsidence and lift-off, but where the mobile bearing implants displayed more of subsidence, the fixed bearing knees showed more lift-off. It might be that the somewhat stiffer cobalt-chromium baseplate or the different joint conformity used in the mobile-bearing knees counteracts any potential effects of the mobile bearing. Level of Evidence: Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence.

Autotransfusion after total knee arthroplasty. Effects on blood cells, plasma chemistry, and whole blood rheology.

Postoperative drain blood was collected and reinfused using the ConstaVac system (Stryker, Kalamazoo, MI) in 30 patients after total knee arthroplasty. Of the total 1.1-L volume of postoperative bleeding, 60% was reinfused. No clinical complications were observed. Differences between venous blood and drain blood and between venous blood and drain blood after separate incubation were studied with respect to acidic and inflammatory effects on blood cells, plasma chemistry, and whole blood rheology. In drain blood, leukocyte and platelet counts were reduced (P < .001), probably as a result of consumption in the wound. Acidic incubation occurs in the drain container because of production of lactate from glucose, with a minimum pH at 5 hours of 7.2. The low pH caused slight but significant erythrocyte swelling (P < .01). The complement C3d indicated leukocyte activation, although of modest magnitude. Despite incubation and complement activation, maximum erythrocyte hemolysis after 24 hours of incubation was less than 1%. Drain blood showed a lower resistance against micropore filtration than venous blood (P < .001), mainly because of the reduced number of leukocytes, and remained unchanged with incubation. Although the autotransfusion system can be improved with respect to blood quality, filtered drain blood should be considered acceptable for reinfusion.

Inferior performance of Boneloc® bone cement in total knee arthroplasty: A prospective randomized study comparing Boneloc® with Palacos® using radiostereometry (RSA) in 19 patients

We compared Boneloc bone cement with conventional cement (Palacos) in fixating the tibial component during 2-5 years in 19 patients with gonarthrosis undergoing total knee arthroplasty in a prospective randomized study. Boneloc displayed significantly larger migration, subsidence and lift-off than Palacos. The difference was identifiable already within 3 months postoperatively, but became significant at 12 months. In the Boneloc group, all components showed subsidence of the posterior part and lift-off of the anterior part of the tibial component, whereas in the Palacos group, the locations of subsidence and lift-off were evenly distributed about the edge of the implant. At 5 years, both Boneloc knees so far investigated were clinical failures with high migration rates. We conclude that, even in total knee arthroplasty, there is a substantial risk that Boneloc leads to inferior clinical results, but later than in hip replacements.

All-poly tibial component better than metal-backed: a randomized RSA study

The quality of the fixation of the tibial component in 21 patients (23 knees) undergoing a cemented total-knee arthroplasty of the Profix design was investigated using radiostereometric analysis during 24 months. The patients were randomized to either an all-polyethylene (AP) or a metal-backed (MB) tibial component. The articulating geometry and the stem design of the implants were identical, as were the operative technique and the postoperative regimen. The results showed no negative consequences as regards fixation using AP tibial components. In all aspects, the AP components displayed magnitudes of migration on par with, or sometimes even lower than their MB counterparts. Five of 11 MB components displayed continuous migration between 1 and 2 years, compared to none of the AP implants, a finding known to be of positive prognostic significance when predicting future aseptic loosening.

Unexpected finding of a marked non-neuronal cholinergic system in human knee joint synovial tissue

The cholinergic anti-inflammatory pathway is a newly discovered pathway. Another recent concept is the existence of a non-neuronal cholinergic system that has, so far, been defined for human tendons, intestine, airways and urinary bladder. The existence of such a system in joint synovial tissue is yet to be described. We therefore aimed to investigate the expression of choline acetyltransferase (ChAT) at both the protein and mRNA level using immunohistochemistry and in situ hybridisation, in human knee synovial tissue from rheumatoid arthritis (RA) and osteoarthritis (OA) patients. The biopsy samples were collected from patients undergoing knee prosthetic surgery. Our results show that both ChAT protein and mRNA is expressed in fibroblast-like and mononuclear-like cells, and to some extent in blood vessel walls in the synovial tissue. The mononuclear-like cells showing ChAT expression were scattered throughout the synovial tissue or located in association with lymphoid aggregates. Thus, we present the first evidence of the existence of a marked non-neuronal cholinergic system in human synovial tissue. The existence of this system could lead to the development of alternative medications to those currently in use. The system might function as a cholinergic anti-inflammatory pathway in synovial tissue. Our observations show that synovial tissue of patients with marked RA or OA, a tissue in which cholinergic innervation is not proven to exist, is supplied with acetylcholine via production in non-neuronal cells within the tissue.

Patients with and without rheumatoid arthritis benefit equally from preoperative epoetin-alpha treatment.

Background Preoperative epoetin-α administration is said to have a limited effect in patients with chronic inflammatory diseases such as rheumatoid arthritis (RA), due to lower iron availability. We studied the effects of preoperative epoetin-α treatment in orthopedic surgery patients in a daily life setting in which iron supplementation was assured, and compared the effects in RA and non-RA patients. Methods In an open, naturalistic, randomized controlled trial, 695 orthopedic surgery patients with preoperative hemoglobin (Hb) values of 10–13 g/dL, either with RA (113) or without RA (582), received either preoperative epoetin-α treatment added to standard care, or standard care alone. Hb values and transfusions were evaluated from entry into the study until 4–6 weeks after surgery. Results Both in RA and non-RA patients, perioperative Hb values were significantly higher and transfusion requirements were significantly lower in epoetin-α treated patients than in control patients (p < 0.001). In RA patients, the outcomes regarding Hb values were not significantly or relevantly different from non-RA patients. Interpretation Just as with orthopedic patients in general, RA patients benefit from preoperative epoetin-α treatment in combination with iron supplementation. We postulate that iron supplementation during epoetin-α therapy in RA patients is important for optimal efficacy.