Articulating spacers compared to fixed spacers for the treatment of infected knee arthroplasty: A follow-up of 37 cases.

BACKGROUND: The standard treatment of a periprosthetic infection after TKA involves a two-stage reimplantation with the intermittent implantation of spacers. Different designs of spacers have been described; currently articulating spacers and fixed spacers are used. The aim of the present study is to compare the advantages/disadvantages of the different spacers. PATIENTS AND METHODS: In this retrospective study we analyzed 37 cases after revision surgery of infected TKA. All patients that received spacers as part of the two-stage reimplantation were included. Exclusion criteria were massive bone loss prior to revision, because the implantation of a mobile spacer would not have been possible. RESULTS: The average ROM was 98.0 (± 14.9) degrees in the articulating spacer group (group 1) and 79.3 (± 22.5) in the group that received the fixed spacers (group 2) before revision surgery started. At a late follow up the average ROM for group 1 was 102.0 (± 8.4) and 79.0 (± 26) for group 2. CONCLUSION: The use of articulating spacers in the two-stage revision for infected total knee arthroplasty is a safe alternative to fixed spacers, that equally preserves ligament balancing and has equal infection eradication rates. A long term improvement of the range of motion following reimplantation of the new joint was, however, not observed.

Expression of vascular endothelial growth factor on chondrocytes increases with osteoarthritis - an animal experimental investigation.

OBJECTIVE: To evaluate the expression of VEGF by chondrocytes of hyaline cartilage during the course of osteoarthritis (OA). METHODS: In 12 white New Zealand rabbits the anterior cruciate ligament (ACL) was resected to create an anterior instability of the knee. In 12 control rabbits only a sham operation without resection of the ACL was done. Four animals of each group were killed at 3, 6, and 12 weeks. The load bearing area was evaluated histologically according to Mankin and by immunostaining for VEGF. RESULTS: In the experimental group, histological grades of OA showed a positive linear correlation with the time after surgery. Immunostaining showed an increased expression of VEGF in the control group after 3 weeks, which dropped to normal after 6 weeks. There was no difference in the progression of OA between control and experimental groups after 3 weeks, but a significant difference was seen after 6 (p=0,01) and 12 (p=0,05) weeks. A significant positive correlation between VEGF expression and the histological grade of OA was found (r = 0.767; p<0.01). CONCLUSIONS: An increase of VEGF expressing chondrocytes occurs during time course of OA.

[Comparison of medium-term clinical and radiological outcome between cemented and cementless medial unicompartmental knee arthroplasty]. / Mittelfristiger, klinischer und radiologischer Vergleich von zementierten und zementfreien, medialen, unikompartimentellen Knieendoprothesen.

AIM: Cementation of tibial implants in total knee arthroplasty is the gold standard considering the high loosening rates of cementless implants. In contrast, only sparse data exist regarding unicondylar arthroplasty due to its lesser use. In this study, we compare cemented with cementless unicondylar knee arthroplasty and aim to define both clinical and radiological differences in treatment outcome. MATERIALS AND METHODS: In a retrospective study, 106 patients who had undergone a medial unicondylar replacement were examined after a mean postoperative period of 8 years. Of these, 42 patients (median age 81 +/- 7 years) had received a cemented and 64 (median age 73 +/- 7 years) a cementless knee arthroplasty by the same surgeon while 7 patients were deceased or could not be reached. Well-established clinical (VAS, HSS, KSS, UCLA, WOMAC) and quality of life (SF-36) scores were used to evaluate treatment outcome. X-rays were performed to evaluate periprosthetic loosening zones, according to Ewald's criteria. RESULTS: The cementless patient group presented significantly better clinical scores (HSS, KSS, UCLA, WOMAC), except in the visual analogue scale (VAS) for pain assessment. The quality of life was significantly better in the cementless group except in the subgroups for physical function, vitality and social role, in that it resembles the normal population. Moreover, radiographic analysis using antero-posterior X-rays revealed significantly more and larger periprosthetic loosening areas in tibial zone 2 in the cementless group. CONCLUSION: The inferior clinical results characterising the cemented group could be attributed to the higher mean age. Regarding the radiological loosening zones, we did not detect any differences in the techniques of fixation, although physical activity and accordingly mechanical stresses were higher in the cementless group.

Gait patterns after intraarticular treatment of patients with osteoarthritis of the knee--hyaluronan versus triamcinolone: a prospective, randomized, doubleblind, monocentric study.

OBJECTIVE: Evaluation of gait performance and muscle activity patterns as well as clinical efficacy and safety after single intraarticular injection with hyaluronan compared with triamcinolone in patients with knee osteoarthritis. MATERIALS AND METHODS: This trial evaluated the influence of a single injection of hyaluronan or triamcinolone on gait pattern and muscle activity. For clinical evaluation a visual analogue scale for pain, Lequesne index, and Knee Society Score were used. Quality of life was assessed with the SF-36. RESULTS: The complete analysis was performed in 50 of 60 patients. 26 patients were treated with triamcinolone and 24 with hyaluronan. Hyaluronan treatment led to significant improvement of range of motion at hip and knee. Significant improvement could be either demonstrated for the pain scale, Lequesne and Knee Society score in both groups. Quality of life showed greater improvement in the triamcinolone group. CONCLUSION: Single application of high-viscosity hyaluronan shows superior range of motion and pain reduction as well as improvement in clinical results. Even if there was a lack of significant differences compared to triamcinolone, this therapy classified as safe and effective in the short follow up.

Proposal for a histopathological consensus classification of the periprosthetic interface membrane.

AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

Expression of the matrix receptor CD44v5 on chondrocytes changes with osteoarthritis: an experimental investigation in the rabbit.

OBJECTIVE: To evaluate the expression of CD44v5 on chondrocytes of hyaline cartilage during the course of osteoarthritis (OA). METHODS: In 12 white New Zealand rabbits the anterior cruciate ligament (ACL) was resected to create an anterior instability of the knee. In 12 control rabbits only a sham operation without resection of the ACL was done. Four animals of each group were killed at 3, 6, and 12 weeks. The loadbearing area was evaluated histologically according to Mankin and by immunostaining for CD44v5. RESULTS: In the trial group, histological grades of OA showed a positive linear correlation with the time after surgery. Immunostaining showed an increased expression of CD44v5 in the control group after 3 and 6 weeks, which dropped to normal after 12 weeks. There was no difference between control and trial groups after 3 and 6 weeks, but a difference was seen after 12 weeks. A significant positive correlation between CD44v5 expression and the histological grade of OA was found (r = 0.314). CONCLUSIONS: An in vivo increase of expression of the hyaluronan receptor CD44v5 occurs during the course of OA. Further studies are needed to evaluate whether this pattern applies to man and whether new treatment approaches might evolve from this knowledge.

[Proposal for the classification of the periprosthetic membrane from loosened hip and knee endoprostheses]. / Vorschlag für eine Konsensus-Klassifikation der periprothetischen Membran gelockerter Hüft- und Knieendoprothesen.

After 10 years, loosening of total joint endoprostheses occurs in about 3 to 10 percent of all patients, requiring elaborate revision surgery. A periprosthetic membrane is routinely found between bone and loosened prosthesis. Further histomorphological examination allows determination of the etiology of the loosening process. Aim of this study is the introduction of clearly defined histopathological criteria for a standardized evaluation of the periprosthetic membrane. Based on histomorphological criteria and polarized light microscopy, four types of the periprosthetic membrane were defined: periprosthetic membrane of wear particle type (type I), periprosthetic membrane of infectious type (type II), periprosthetic membrane of combined type (type III), periprosthetic membrane of indifferent type (type IV). Periprosthetic membranes of 268 patients were analyzed according to the defined criteria. The correlation between histopathological and microbiological diagnosis was high (89%, p<0,001), the inter-observer reproducibility was sufficient (95%). This classification system enables a standardized diagnostic procedure and therefore is a basis for further studies concerning the etiology of and pathogenesis of prosthesis loosening.

Differential induction and regulation of matrix metalloproteinases in osteoarthritic tissue and fluid synovial fibroblasts.

OBJECTIVES: To investigate the secretion profiles of matrix metalloproteinases (MMP) and their inhibitors (TIMP) in synovial fluid-derived fibroblasts and to compare them with those of tissue-derived fibroblasts. METHODS: Fibroblast cultures established from synovial tissues (TSC) and fluids (FSC) of the same OA patients were stimulated with tumor necrosis factor(TNF)-alpha, interleukin(IL)-1alpha, IL-1beta, IL-6 and a combination of TNFalpha and IL-1beta. Cocultures of fibroblasts and cartilage were stimulated either with the cytokine combination or with osteoarthritic synovial fluid. Secretion of MMP-1, MMP-3, MMP-8, MMP-13, TIMP-1, and TIMP-2 was measured by enzyme-linked immunosorbent assay. Gelatin zymography and immunoblotting were performed to demonstrate enzyme activity. RESULTS: TNFalpha, IL-1alpha, and IL-1beta led to marked increases in MMP-1 and MMP-3 release (up to 4.2-fold and 547-fold, respectively) by synovial fibroblasts, whereas secretion of MMP-13 was induced by concomitant administration of TNFalpha and IL-1beta. Expression of intracellular MMP-8 was stimulated by cytokines, but adhesion of synovial fibroblasts to cartilage was required for the release. Throughout the study, significantly higher levels of secreted MMPs were observed in stimulated FSC compared to TSC cultures. Furthermore, increases in MMP secretion were not accompanied by increases in secreted TIMP-1 and TIMP-2, resulting in marked imbalances between enzyme and inhibitor levels. CONCLUSIONS: The results provide strong evidence for a significant impact of synovial-derived MMPs on cartilage destruction in OA. In this context, fibroblasts present in the synovial fluid appeared to play an outstanding role.

Quality of life 20 years after arthrodesis of the ankle. A study of adjacent joints.

biotalar fusion is considered to be the standard treatment for end-stage post-traumatic arthritis of the ankle. We report a retrospective, objective long-term study of the quality of life of 17 patients with 18 arthrodeses of the ankle, over a period of more than 20 years. We looked particularly for correlation between clinical and radiological signs of osteoarthritis in adjoining joints. At serial physical examinations, clinical grades were awarded according to the Olerud Molander Ankle (OMA) score. Any degree of degenerative change in the adjoining joints was recorded on standing radiographs. Patients filled out a SF-36 Health Survey form. Subjectively, 50% of patients were not handicapped in the performance of daily activities and 44% were in the same job as at the time of injury. At follow-up the mean OMA score was 59.4 points, the visual analogue scale was 1.99 and the radiological score was 2.7. The SF-36 for physical function, emotional disturbance and bodily pain revealed significant deficits. There was a significant correlation between the OMA and the radiological score (p = 0.05), and between the clinical and the SF-36 score (p = 0.01), but no significant correlation between the radiological score and the SF-36 score. Arthrodesis of the ankle leads to deficits in the functional outcome, to limitations in the activities of daily living and to radiological changes in the adjoining joints. The clinical outcome score correlates closely with the SF-36 score.

[Correlation of electromyography and clinical results after bicondylar knee joint prosthesis implantation]. / Korrelation von elektromyographischen und klinischen Ergebnissen nach bikondylären Kniegelenksprothesen.

AIM OF THE STUDY: To investigate clinical findings in patients receiving bicondylar sledge prostheses, and their correlation with electromyographic measurements in comparison with healthy volunteers. MATERIAL AND METHODS: An average of 31.9 months after implantation of a bicondylar sledge prosthesis, 15 patients were clinically examined and compared with 11 control subjects. Electromyographic measurements of the rectus femoris, vastus medialis and lateralis, semitendinosus, biceps femoris, tibialis anterior, and gastrocnemius muscles were obtained. RESULTS: All clinical scores were significantly poorer in the patient group. The activity of the vastus lateralis was significantly reduced. The activity in the lower leg of the operated side was significantly higher than in the control group. Significant differences were found in the tibialis anterior and gastrocnemius muscles between controls and patients. Analysis of the correlation between the clinical scores and the electromyographic measurements showed no significance. CONCLUSION: The clinical results correlated only slightly with the electromyographic activity of the muscles investigated. The commonly presumed quadriceps insufficiency was not confirmed.