Biomedical subjects

Timo Järvelä

Publications and source records attributed to Timo Järvelä.

9 recordsLinked to original sources

PubMed2007

Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective, randomize clinical study.

Anatomical observation and biomechanical studies have shown that the anterior cruciate ligament (ACL) mainly consists of two distinct bundles, the anteromedial (AM) bundle and posterolateral (PL) bundle. Conventional single-bundle ACL reconstruction techniques have focused on the restoration of the AM bundle while giving limited attention to the PL bundle. The purpose of this prospective, randomized clinical study is to compare the outcomes of ACL reconstruction when using either double-bundle or single-bundle technique and bioabsorbable interference screw fixation, and similar rehabilitation with both techniques. Sixty-five patients were randomized into either double-bundle (n = 35) or single-bundle (n = 30) ACL reconstruction with hamstring tendons and bioabsorbable screw (Hexalon, Inion Company, Tampere, Finland) fixation in both groups. The evaluation methods were clinical examination, KT-1000 arthrometer measurements, radiographic evaluation, as well as International Knee Documentation Committee and Lysholm knee scores. There were no differences between the study groups preoperatively. For an average of 14 months of follow-up (range 12-20 months), 30 patients of the double-bundle group and 29 patients of the single-bundle group were available (91%). At the follow-up, the rotational stability, as evaluated by pivot shift test, was significantly better in the double-bundle group than in the single-bundle group. However, in anterior stability of the knee, there was no significant difference between the groups. None of the patients in the double-bundle group had graft failure, while four patients in the single-bundle group had. In addition, knee scores were equal at the follow-up, and all the results were significantly better at the follow-up than preoperatively, in both groups.

Absorbable Implants↗

PubMed2006

Antioxidant enzymes in oligodendroglial brain tumors: association with proliferation, apoptotic activity and survival.

Purpose of the study was to investigate the relationship between antioxidant enzyme expression and clinicopathological features in oligodendroglial tumors. The expression of antioxidant enzymes and related proteins (AOEs), manganese superoxide dismutase (MnSOD), thioredoxin (Trx), thioredoxin reductase (TrxR) and gammaglutamylcysteine synthetase catalytic and regulatory subunits (GLCL-C and GLCL-R), was studied in 85 oligodendroglial tumors. The material included 71 primary (43 grade II and 28 grade III) and 14 recurrent (6 grade II and 8 grade III) tumors. Fifty-seven cases were pure oligodendrogliomas and 28 were mixed oligoastrocytomas. Immunoreactivity for MnSOD was found in 89%, Trx in 29%, TrxR in 76%, GLCL-C in 70% and GLCL-R in 68% of cases. Increased Trx expression was associated with higher tumor grade, cell proliferation and apoptosis (P=0.006, P=0.001 and P=0.003, Mann-Whitney test). Pure oligodendrogliomas showed more intense staining than oligoastrocytomas, especially for MnSOD (P=0.002, Mann-Whitney test). In the total series Trx was associated with poor prognosis in univariate survival analysis (P=0.0343, log-rank test) and furthermore in Cox multivariate analysis (P=0.009) along with age (P=0.002). The results suggest that the expression of Trx has a correlation to patient outcome and that there may be some association between AOEs, like MnSOD and Trx, and clinicopathological features of oligodendrogliomas.

Antioxidants↗

PubMed2006

Amplification of the epidermal growth factor receptor in astrocytic tumours by chromogenic in situ hybridization: association with clinicopathological features and patient survival.

Chromogenic in situ hybridization (CISH) was used to detect amplification of the epidermal growth factor receptor (EGFR) gene in tissue microarrays of tumours derived from 287 patients with grade II-IV diffuse astrocytomas. Amplification was found in 32% of the tumours with a highly significant association with histological grade (4% in grade II, 21% in grade III and 39% in grade IV; P < 0.001). Amplification of the EGFR gene was more common in primary than in secondary glioblastomas (41%vs. 16%, P = 0.033). Overexpression of EGFR mRNA and protein (wild-type and vIII variant) was found to correlate with EGFR gene amplification (P = 0.028, P = 0.035 and P = 0.014 respectively), but wild-type EGFR protein was also frequently overexpressed in tumours without EGFR gene amplification. Patients with older age (P < 0.001) and tumours with lack of p53 overexpression (P = 0.03) and higher apoptosis rate (P < 0.001) had significantly more EGFR gene amplifications than their counterparts. No such correlation with apoptosis was found in glioblastomas. The survival of patients with EGFR gene-amplified grade III tumours was significantly shorter than in those with grade III non-amplified tumours (P = 0.03). No such difference was noted in glioblastomas (grade IV tumours). Our data verify the central role of EGFR in the pathobiology of astrocytic tumours, and highlight the advantages of CISH as a simple and practical assay to screen for EGFR gene amplification in astrocytic tumours.

Adolescent↗

PubMed2005

Reconstruction of ruptured patellar tendon after total knee arthroplasty: a case report and a description of an alternative fixation method.

Patellar tendon rupture after total knee arthroplasty is a rare, but often catastrophic complication. Many different reconstruction techniques of patellar tendon rupture have been described with variable and often discouraging results. A case report with patellar tendon rupture after a total knee arthroplasty is presented. Also, an alternative surgical technique of reconstruction of the patellar tendon using a semitendinosus-gracilis (STG) graft with an interference screw and a staple fixation enabling an immediate mobilization is described.

Aged↗

PubMed2005

[Painful knee].

Explore the source record for details and available documents.

Acute Disease↗

PubMed2004

Interference screw fixation of soft tissue grafts in anterior cruciate ligament reconstruction: part 1: effect of tunnel compaction by serial dilators versus extraction drilling on the initial fixation strength.

BACKGROUND: Compaction of the bone-tunnel walls by serial dilation is believed to enhance the interference screw fixation strength of the soft tissue grafts in anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Serial dilation enhances the fixation strength of soft tissue grafts in ACL reconstruction over extraction drilling. STUDY DESIGN: Randomized experimental study. METHODS: Initial fixation strength of the doubled anterior tibialis tendon grafts (fixed with a bioabsorbable interference screw) was assessed in 21 pairs of human cadaver tibiae with either serially dilated or extraction-drilled bone tunnels. The specimens were subjected to a cyclic-loading test, and those surviving were then tested using the single-cycle load-to-failure test. RESULTS: During the cyclic-loading test, there were 3 fixation failures in the serially dilated and 6 failures in the extraction-drilled specimens but no significant stiffness or displacement differences between the groups. In the subsequent load-to-failure test, the average yield loads were 473 +/- 110 N and 480 +/- 115 N for the 2 groups respectively (P =.97) and no difference with regard to stiffness or mode of failure. CONCLUSIONS: Serial dilation does not increase the strength of interference fixation of soft tissue grafts in ACL reconstruction over extraction drilling. CLINICAL RELEVANCE: The results of this experiment do not support the use of serial dilators in ACL reconstruction.

Adolescent↗

PubMed2004

Interference screw fixation of soft tissue grafts in anterior cruciate ligament reconstruction: part 2: effect of preconditioning on graft tension during and after screw insertion.

BACKGROUND: Preconditioning of tendon grafts is believed to eliminate natural viscoelasticity of the tendons and prevent knee laxity after anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Preconditioned ACL grafts maintain their initially set tension. STUDY DESIGN: Randomized experimental study. METHODS: Forty-two human anterior tibialis (AT) tendon grafts were subjected to either no preconditioning (group 1), cyclic preconditioning (group 2), or isometric preconditioning (group 3). The residual graft tension was then recorded immediately after the application of an initial graft tension of 80 N and fixation into tibia with an interference screw, as well as 10 minutes later. In another experiment, the residual graft tension was recorded 1, 10, and 60 minutes after 10 AT and quadrupled hamstring tendon (HT) grafts alone (no fixation) had been subjected to isometric preconditioning (80 N). RESULTS: Immediately after screw insertion, the residual (AT) graft tensions were 79 +/- 19 N, 100 +/- 17 N, and 102 +/- 15 N in groups 1 through 3, respectively. Ten minutes later, the corresponding values were 49 +/- 16 N, 60 +/- 11 N, and 64 +/- 12 N. For the AT and HT grafts alone, the residual graft tensions were 67 +/- 2 N and 67 +/- 2 N, 45 +/- 2 N and 46 +/- 4 N, and 29 +/- 3 N and 34 +/- 5 N at 1, 10, and 60 minutes, respectively. CONCLUSIONS: A steady decrease (-60% within 60 minutes after initial tensioning) occurs in the initially set tension of the soft tissue ACL grafts. CLINICAL RELEVANCE: Clinically applicable preconditioning protocols cannot eliminate the intrinsic viscoelasticity from ACL soft tissue grafts, and thus, the reasonableness of preconditioning per se is questioned in ACL reconstruction.

Adolescent↗

PubMedDate not supplied

Ultrasonographic and power Doppler evaluation of the patellar tendon ten years after harvesting its central third for reconstruction of the anterior cruciate ligament: comparison of patients without or with anterior knee pain.

BACKGROUND: The long-term morphologic changes in the patellar tendon after harvesting its central third for the reconstruction of the anterior cruciate ligament have not been reported. HYPOTHESIS: Sonographic morphologic changes in the harvested patellar tendon are common 10 years after the harvesting procedure. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-one patients who had undergone an anterior cruciate ligament reconstruction using central-third bone-patellar tendon-bone autograft with a closure of the patellar tendon defect were included in this study. An ultrasonographic and Power Doppler examination was performed at a mean follow-up of 10 years. RESULTS: Ultrasonography of the harvested patellar tendon showed intratendinous calcification in 9 patients, hypoechoic lesion in 20 patients, hyperechoic lesion in 1 patient, and peritendinous changes in 1 patient. Only 3 (9.7%) of the 31 patients had no changes in the harvested patellar tendon. No abnormality was visible in the contralateral (normal) patellar tendons of the 31 patients. The harvested patellar tendon was significantly thicker than the contralateral patellar tendon (P < 0.05). CONCLUSIONS: Sonographic morphologic changes of the patellar tendon were common 10 years after the harvesting procedure, although no evidence of inflammatory process, as could be seen in Power Doppler flow, was found inside of any patellar tendon.

Adolescent↗

PubMedDate not supplied

Anterior knee pain after intramedullary nailing of a tibial shaft fracture: an ultrasound study of the patellar tendons of 36 patients.

OBJECTIVES: Chronic anterior knee pain is a common complication following intramedullary nailing of a tibial shaft fracture. The etiology of pain is often not known. This study sonographically examined the patellar tendons of patients with a nailed tibial shaft fracture. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Fifty consecutive patients with a nailed tibial shaft fracture were initially included in the study. Thirty-six of them could be measured at an average of 2.5 +/- 0.5 years after nail insertion (1.0 +/- 0.3 years after nail extraction). INTERVENTION: Reamed intramedullary nailing with 2 interlocking bolts at both ends of the nail (Grosse-Kempf-nail, Howmedica). MAIN OUTCOME MEASUREMENTS: The ultrasound investigation of the patellar tendons of the 36 patients. RESULTS: Twelve (33%) patients were painless and 24 (67%) patients had anterior knee pain at follow-up. With the reference to the mean difference in the thickness of the distal part of the patellar tendon in the operated limb versus nonoperated limb, the result was 1.4 +/- 1.1 mm in the chronic pain group and 2.6 +/- 2.5 mm in the painless group (P = 0.135, [95% confidence interval for the group difference = -0.4-2.8]). The corresponding values for the proximal part of the patellar tendon was 1.4 +/- 1.3 mm in the chronic pain group and 2.3 +/- 2.3 mm in the painless group (P = 0.251, [95% confidence interval for the group difference = -0.7-2.4]). There were no statistically significantly differences between study groups in the blood circulation of the patellar tendon or at the entry point, calcification of the patellar tendon, granulation tissue at the entry point, or occurrence of low echo areas in the patellar tendon. CONCLUSION: After intramedullary nailing of a tibial shaft fracture, patients with or without anterior knee pain show similar changes in the ultrasound investigation of their patellar tendons. Based on those findings, it does not appear to make any difference as to the approach used (paratendinous or transtendinous) for intramedullary nailing of the tibia.

Adult↗