PubMed Health⌕ Search

Biomedical subjects

P Paavolainen

Publications and source records attributed to P Paavolainen.

At least 19 recordsLinked to original sources
PubMed2006

Randomized clinical trial of Lichtenstein patch or Prolene Hernia System for inguinal hernia repair.

BACKGROUND: In this randomized prospective study the short- and long-term outcomes of patients undergoing inguinal hernia repair with either Lichtenstein mesh or the Prolene Hernia System (PHS) were evaluated. METHODS: Postoperative pain and time to return to work, driving and sporting hobbies were recorded after 300 inguinal hernia repairs done by one of the two methods. Long-term sequelae and complications were assessed at follow-up visits 1 week, 1 month and 1 year after the operation. RESULTS: The median duration of operation for unilateral primary hernia was 37 min for the Lichtenstein operation and 27 min for the PHS procedure (P < 0.001). Postoperative pain was similar after both operations. Median sick leave was 7 days in both groups. Time to driving a car was 4 versus 3 days, and time to return to sporting hobbies 13 versus 11 days, in the Lichtenstein and PHS groups, respectively. Apart from a residual femoral hernia after Lichtenstein repair, no recurrent inguinal hernias were detected. CONCLUSION: Both Lichtenstein and PHS methods resulted in rapid recovery and low recurrence rates. The PHS operation was significantly quicker.

Adult↗
PubMed2006

Cancer incidence and causes of death among total hip replacement patients: a review based on Nordic cohorts with a special emphasis on metal-on-metal bearings.

All patients with total hip arthroplasty (THA) are exposed to soluble or particulate forms of Co and Cr. Adverse effects of these wear products are not known. Data from Nordic registries is used to estimate adverse effects on a large scale, based mostly on metal-on-polyethylene bearings. Cancer incidence was in line with the general population when the patients were operated on for all indications and significantly decreased when the indication was primary osteoarthritis. Stomach cancer and colorectal cancers were significantly reduced and prostate cancer and skin melanoma significantly increased. There was no significant excess of cancer in target organs, i.e. liver, kidney, or haematopoietic cancers. THA patients had reduced mortality and extended life expectancy compared with standard Nordic populations. All-site cancer incidence of the first-generation metal-on-metal McKee-Farrar patients operated on for primary osteoarthritis was in line with the general population after follow-up for up to 28 years. General mortality of these patients was also reduced and they also had an extended life expectancy. Temporary increases in haematopoietic cancers at different follow-up periods were seen in some cohorts. This malignancy deserves a special record linkage monitoring while large numbers of young patients are provided with the second generation of metal-on-metal prostheses.

Arthroplasty, Replacement, Hip↗
PubMed2001

Surgery vs orthosis vs watchful waiting for hallux valgus: a randomized controlled trial.

CONTEXT: Hallux valgus is a common foot deformation in adults, but evidence for effectiveness of surgical and conservative treatments for this condition is limited. OBJECTIVE: To compare the effectiveness of surgical and orthotic treatment with no treatment in patients with hallux valgus. DESIGN AND SETTING: Randomized controlled trial conducted in 4 general community hospitals in Finland in 1997-1998, with a follow-up period of 12 months. PARTICIPANTS: Two hundred nine consecutive patients (mean age, 48 years; 93% women) with a painful bunion and a hallux valgus angle 35 degrees or less. INTERVENTIONS: Patients were randomly assigned to surgery (distal chevron osteotomy; n = 71), orthosis (n = 69), or a 1-year waiting list (control group, n = 69). MAIN OUTCOME MEASURES: Pain intensity during walking on a visual analog scale (0-100), patient assessment of global improvement, number of painful days, cosmetic disturbance, footwear problems, functional status, and treatment satisfaction, compared among treatment groups. RESULTS: Follow-up rates at 6 and 12 months were 99% and 98%, respectively. At 6 months, pain intensity decreased more in the surgical group than in the control group (adjusted mean differences, -20 [95% confidence interval (CI), -28 to -12]) and more in orthosis than in the control groups (adjusted mean difference, -14 [95% CI, -22 to -6. At 1 year, pain intensity decreased more in the surgical than in the control groups (adjusted mean difference, -19 [95% CI, -28 to -10]) and more than in the surgical and orthosis groups (adjusted mean difference, -14 [95% CI, -22 to -5]). At 1 year, 83%, 46%, and 24% in the surgery, orthosis, and control groups, respectively, thought they had improved compared with baseline (number needed to treat), 1.7 between surgical and control groups). Number of painful days, cosmetic disturbance, and footwear problems were least and functional status and satisfaction with treatment were best in the surgical group. CONCLUSIONS: Surgical osteotomy is an effective treatment for painful hallux valgus. Orthoses provide short-term symptomatic relief.

Female↗
PubMed2001

The Finnish Arthroplasty Register: report of the hip register.

The Finnish Arthroplasty Register was established in 1980. Between 1980 and 1999, 62,841 primary and 12,224 revision total hip arthroplasties (THA) were recorded. The annual number of both primary and revision THA has increased: in 1999, the incidence of primary THAs was 93/100,000. 174 implant designs have been used, but the 6 commonest implants comprised 82% in 1999. Since the late 1980s, more than 40% of the hips were inserted without cement. Over 47% of the cementless primary hip prostheses were used in patients younger than 60 years and over 93% of the cemented primary hips were used in patients 60 years or older. The 10-year survival rate was 72 (95% CI 67-76)% in patients younger than 55 years and 90 (89-91)% in patients older than 70 years. The commonest reasons for revision were aseptic loosening (65%), dislocation (9%) and infection (7%). In revisions, the 5-year survival of the cementless hip prosthesis improved over time: it was 85 (82-87)% in 1985-1989, 89 (88-91)% in 1990-1994 and 92 (88-95)% in 1995-1999. There are striking differences between the Arthroplasty Registers of Scandinavia as regards the end-point definition of survival. The Finnish Arthroplasty Register considers all reasons for revisions as the end-point of survival, but the Swedish register takes into account only aseptic loosening, so direct comparisons between registers are not possible. Recent data from the Finnish Arthroplasty Register indicate that the results of total hip replacements are improving in Finland. With the civic registration number, one can link and match data files. For example, with use of the Finnish Cancer Register, we found no increase in the risk of cancer after a THA.

Arthroplasty, Replacement, Hip↗
PubMed2000

Expression of extracellular matrix genes: transforming growth factor (TGF)-beta1 and ras in tibial fracture healing of lathyritic rats.

Experimental osteolathyrism, induced by dietary aminoacetonitrile (AAN), was used to study the effect of altered extracellular matrix on the expression of connective tissue components in long bone healing. AAN inhibits lysyl oxidase, which is needed for the formation of collagen cross-link precursors, and is also shown to act as a regulator of Ras. Fractured tibias in lathyritic rats develop excessive amounts of mechanically weak callus tissue with irregular cartilage and reduced glycosaminoglycan accumulation. Cartilage-specific proteins (collagen types II, IX, and X and aggrecan) were expressed temporally much wider in lathyritic calluses than in the controls, and active transcription was observed even during the fibrous and ossifying stages. Soft connective tissue was still present in 2- and 3-week-old lathyritic calluses and could explain the elevated type III collagen, biglycan, and decorin mRNA levels. Both transforming growth factor (TGF)-beta1 and c-Ha-ras, which control cell growth and differentiation, were upregulated during the cartilaginous stage. The maximal expression of TGF-beta1 preceded that of ras in osteolathyrism.

Animals↗
PubMed1999

Cancer incidence in Finnish hip replacement patients from 1980 to 1995: a nationwide cohort study involving 31,651 patients.

Nationwide, computer-based reporting of all arthroplasties performed in Finland was started in January 1980. Using data from these records, a cohort of 31,651 polyethylene-on-metal total hip arthroplasty (THA) patients was followed up for cancer, using Finnish Cancer Registry data, from 1980 to 1995. During follow-up, 2,367 cancers were observed. There were statistically significantly fewer cancers among the THA patients (standardized incidence ratio [SIR], 0.90; 95% confidence interval [CI], 0.87-0.93). SIRs for cancers of the lung (0.69) and stomach (0.77) were significantly below unity. There was no significantly increased risk at any site. The SIR for cancer overall in male THA patients was below unity during the first 3 years after THA but returned to unity thereafter. The low SIR among men during the first 3 years was largely because the lung cancer SIR was 0.47 (95% CI, 0.35-0.62). In women, the SIR remained around 0.93 throughout follow-up. The SIR for stomach cancer was below unity only in women (SIR, 0.67; 95% CI, 0.51-0.86). For cancer of the urinary bladder, the SIR during the first 3 years after THA was below unity but later slightly above it (SIR, 1.24 in relation to > or =3 years of follow-up; 95% CI, 0.99-1.52). For myeloma and leukemia, SIRs were greater than unity only for THA patients followed up for 3 to 9 years. The study findings, in contrast to previously reported findings, do not indicate that there is any increased risk of hematopoietic cancers after THA using polyethylene-on-metal prostheses. SIRs relating to soft tissue cancers and bone sarcomas did not differ significantly from unity. No sarcoma was observed at the site of a prosthesis. THA seems to play no major role in cancer causation.

Arthroplasty, Replacement, Hip↗
PubMed1999

Cancer incidence after total knee arthroplasty: a nationwide Finnish cohort from 1980 to 1996 involving 9,444 patients.

A nationwide, computer-based survey of all total joint arthroplasties performed in Finland has been carried out since January 1980. From these records, a cohort of 9,444 patients, with 51,756 person-years, after primary operation with a total polyethylene-on-metal knee arthroplasty (TKA) was followed up for cancer through the Finnish Cancer Register up to December 31, 1996. During the follow-up, 706 cancers were observed. The expected number, based on national rates, was 719; therefore, the standardized incidence ratio (SIR) for all cancers was 0.98. The SIRs for non-Hodgkin's lymphoma (1.40), Hodgkin's disease (1.24) and multiple myeloma (1.54) were increased, but only that of non-Hodgkin's lymphoma was statistically significant 3-10 years after the operation. The numbers of observed cases of prostate cancer exceeded that of expected, with a SIR value of 1.49. A low SIR of lung cancer was observed among men, especially during the first 3 years (0.61), but not in women. The SIR for colon cancer was below unity in women only (SIR 0.70). The SIR for cancer of the urinary organs was close to unity (0.97). SIR relating to soft tissue and bone cancer did not differ significantly from unity, and none of the 6 sarcomas was observed at the site of a prosthesis. The overall cancer risk after TKA done for primary osteoarthrosis seems not to be increased. The increases in lymphoma and prostate cancer risk, however, are observations that could be related to TKA and justify further follow-up of the cohort.

Adult↗
PubMed1998

Major fibrillar collagens and fibronectin in an experimental nonunion: an immunohistochemical study.

We studied in a rat pseudoarthrosis model the time sequence of expression and distribution of fibronectin and collagens I, II, III and V. Collagens and fibronectin were immunolocalized at the light microscopic level. The major difference from the normal healing pattern was the extension of collagen II and cartilage into the interfragmentary area and at the circumference of the periosteal callus, without any bridging chondral or bony elements in the fracture gap. The formation of a fibrous bond, consisting mostly of collagen III and fibronectin, was observed. This speaks in favor of the failure of the multipotentional mesenchymal stem cells to change the fracture-healing process towards fibroblast proliferation and the production of tissue unable to mineralize. The decisive zone for mineralization of the callus appeared to be the area of the hypertrophied chondrocytes near the periosteal ossification front.

Animals↗
PubMed1997

Causes of death after hip arthroplasty in primary arthrosis.

The causes of death in 1,018 patients operated on for primary osteoarthrosis with cemented total hip arthroplasty (THA) were compared with those of age- and sex-matched orthopaedic control patients and those of the general population in Finland. The mean follow-up period was 12 years for the THA patients and 11 years for the control patients. During the first 4 years after surgery, the mortality of the THA patients from circulatory diseases was significantly increased compared with that of the orthopaedic control patients; the number of deaths in patients with THA was 34 compared with 17 for orthopaedic control patients, the relative risk being 2.00 (95% confidence interval, 1.13-3.54). During the 10-year period after the surgery, the relative risk of death of the THA patients compared with the orthopaedic control patients was 1.50 for death from circulatory diseases (95% confidence intervals, 1.11-2.00), 0.42 for accidental death (95% confidence interval, 0.55-1.08), 0.74 for death from cancer, and 0.77 for death from other causes. The observed numbers of deaths from circulatory diseases or by accidents for patients with THA during a postoperative time frame of 5 to 23 years did not differ from the numbers expected for an age- and sex-matched subgroup of the Finnish population. The number of deaths from cancer was less than expected (P = .046).

Accidents↗
PubMed1997

Costs and cost-effectiveness in hip and knee replacements. A prospective study.

The extensive benefits of the total hip (THA) and knee (TKA) replacements are well documented, but surprisingly little is known about their economics. We assessed costs, cost-effectiveness (C/E), and patient-related C/E variances in THA and TKA from data on 276 THA and 176 TKA patients. Patients with primary arthrosis, primary operation, and total joint replacement were recruited from seven hospitals between March 1991 and June 1992. Their use of health and other welfare services together with health-related quality of life (HRQoL) were measured before the surgery and at 6, 12, and 24 months postoperatively. HRQoL was assessed by the 15D, a 15-dimensional HRQoL instrument, and the Nottingham Health Profile. Costs were assessed from questionnaire responses, the Finnish Hospital Discharge Register, and Finnish Arthroplasty Register. Total hospital costs per patient were 45,000 FIM (US $10,500) for THA and 49,600 FIM (US $11,500) for TKA. Prosthesis costs comprised 21% of these costs in THA and 24% in TKA. On average, hip patients gained more in terms of HRQoL, and the operations were more cost-effective. The C/E ratio for younger (< or = 60 years) knee patients did not differ from those in all age groups of hip patients, whereas TKAs in those over 60 years had a worse C/E ratio compared with all other patient subgroups. It was concluded that allocation efficiency can be improved by considering not only the intervention but also patient characteristics such as age. Indeed, the C/E ratio varied more across age groups of knee patients than between average THA and TKA patients.

Adult↗
PubMed1997

Short-term external support promotes healing in semirigidly fixed fractures.

The effect of different postoperative treatments on the healing of rabbit femoral shaft fractures fixed semirigidly by intramedullary nailing was investigated clinically, radiologically, and mechanically. A unilateral transverse midfemoral fracture was performed on all rabbits and was treated with an intramedullary nailing without previous reaming. When the operated limb was immobilized postoperatively by a splint with the knee in extension for 1 week (Group 2), nine of 10 fractures healed. When immobilized in extension for 7 weeks (Group 3), eight of 10 healed. When immobilized in flexion for 7 weeks (Group 4), five of 10 fractures were clinically healed within 7 weeks. When the limb was not immobilized by external support (Group 1), only one of 10 healed. The radiologic healing correlated with the clinical healing in each group. There were no statistically significant differences among the groups in the quantity of callus or in the biomechanical properties of the healed fractures. The results indicate that even a short term additional external support of the limb with the knee in extension was advantageous to the healing of femoral shaft fractures fixed semirigidly by intramedullary nailing.

Animals↗
PubMed1996

Quality of life and functional ability in hip and knee replacements: a prospective study.

The impact of hip (THA) and knee arthroplasty (TKA) on patients' health-related quality of life (HRQOL), physical ability and functioning was assessed in a two year follow-up study of 276 hip and 176 knee patients. The eligibility criteria were a diagnosis of primary arthrosis, a primary operation, and total joint arthroplasty. Patients were interviewed by questionnaire prior to the operation and 6, 12 and 24 months after the surgery. Subjective health outcomes were assessed with the Nottingham Health Profile and the 15D, a fifteen dimensional HRQOL measure. Patients' physical ability was assessed using measures of activities of daily living, and of physical mobility. Patient related outcome variations were analyzed by regression models. Major improvements were observed for pain, sleep and physical mobility. On average, in most of the quality of life dimensions the patients attained a similar quality of life as the comparable general population and only 4.7% of hip and 9.7% of knee patients had a worse HRQOL score at all three post-operative measurements than at baseline. Naturally, those with the poorest HRQOL pre-operatively gained most from the operation. High age did not lessen HRQOL gains from THA, but in TKA the oldest patients gained least in terms of 15D scores. Hip, but not knee patients with a long education tended to have greater improvements in quality of life and functional ability.

Activities of Daily Living↗
PubMed1996

Hospital- and patient-related characteristics determining length of hospital stay for hip and knee replacements.

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are among the most prestigious health care technologies. Their popularity has grown rapidly, and an increasing proportion of health care resources is allocated to them. We studied patient- and hospital-related factors that cause variation in a major determinant of hospital costs, the length of hospital stay (LOS) for THA and TKA. We gathered data on 10,288 hip and 5,173 knee patients with primary or secondary arthrosis from the Finnish Arthroplasty Register, which we linked with the Finnish Hospital Discharge Register. Patient- and hospital-related variations in LOS were explained using regression models. Of the patient-related factors, complications caused the greatest prolongation of hospital stay, but patient's age, gender, and charge category also influenced LOS. Hospital-related factors were major causes of LOS variation. In the hospitals the average case-mix-adjusted LOS ranged from less than a week to 3 weeks. The number of arthroplasties performed in hospital was inversely related to LOS. The within-hospital LOS figures for THA and TKA were strikingly similar and persistent.

Adult↗
PubMed1996

Cancer risk after metal on metal and polyethylene on metal total hip arthroplasty.

The incidence of cancer after metal on metal total hip arthroplasty (McKee-Farrar) and polyethylene on metal total hip arthroplasty (Brunswik, Lubinus) was compared with that of the general population in Finland. The mean followup time for the patients who had metal on metal total hip arthroplasty was 15.7 (9092 person years) and for the patients who had polyethylene on metal total hip arthroplasty it was 12.5 years (19,846 person years). One hundred thirteen malignant cancers were observed in patients who had metal on metal total hip arthroplasty and 212 were observed in patients who had polyethylene on metal total hip arthroplasty. The standardized incidence ratio for all cancers of the metal on metal arthroplasty group was 0.95 (95% confidence limits 0.79-1.13) and that of the polyethylene on metal arthroplasty group was 0.76 (95% confidence limits 0.68-0.86). The risk of total cancer in the patients who had metal on metal total hip arthroplasty was 1.23-fold compared with that of the patients who had polyethylene on metal total hip arthroplasty. Both groups had significantly less lung cancer than the general population: the leukemia incidence in the patients who had metal on metal total hip arthroplasty was slightly increased (observed to experienced 7/3.03, standardized incidence ratio 0.61; 95% confidence limits 0.17-1.56). The leukemia rate of the patients who had metal on metal total hip arthroplasty was 3.77-fold compared with that of the patients who had polyethylene on metal total hip arthroplasty, but this difference was not statistically significant. No sarcomas were observed at the site of the prosthesis. The incidence of the other forms of cancers did not differ significantly from those in the general population. The observed variation in the incidence of different cancers among patients who had total hip arthroplasty compared with the general population suggests that factors other than total hip arthroplasty play a major role in the origin of cancer.

Aged↗
PubMed1996

Connective tissue parameters in experimental nonunion.

A previously developed experimental model for producing nonunions in rats was used to study the biochemical changes of connective tissue parameters in impaired fracture repair. The model is based on rotational instability between the fracture fragments. A mid-diaphyseal femoral osteotomy was performed on 30 male rats and fixed with a loose-fitting intramedullary nail. The rats were killed 1, 2, 3, 7, 9, and 12 weeks postoperatively, and the development of nonunions was verified with radiographs. The calluses were dissected free and set for biochemical analysis. The contents of nitrogen, hydroxyproline, calcium, and phosphorous, as well as the RNA/DNA ratio, were determined. It appeared that in the impaired fracture repair there is an extended matrix production phase continuing until 7 weeks postoperatively. Simultaneously, the number of callus cells increased, indicating an extended expression of the mitotic signals for callus cells. The net synthesis of collagen matrix seemed to be sufficient, but the mineral binding capacity of the newly synthetised collagen was impaired. Later, the cessation of chondrogenic and osteogenic activity could be observed with the formation of nonmineralized fibrous tissue between the fracture fragments.

Animals↗
PubMed1995

An experimental model for non-union in rats.

Few studies of the biological changes which occur in impaired fracture repair and non-union have been carried out, and creating an appropriate model for advanced biochemical studies of non-union has proved to be a demanding task. This paper presents a standardized experimental model for producing non-union in rat femurs, for use in biochemical studies of non-union. A mid-diaphyseal fracture with a rotationally unstable fixation was performed in rats with a mean weight of over 330 g and mean age of over 10 weeks. Radiologically and histologically (Alcian blue and Safranin O stainings) the signs of undisturbed fracture healing were observed until 3 weeks after the fracture. Thereafter there was evidence that chondrocytic activity ceased, with no signs of formation of calcifying bridging callus. From the seventh week onwards, all elements necessary for a calcifying callus were lost; and the histological picture tended to be of scar tissue bond between the fracture ends.

Animals↗
PubMed1995

Health and quality of life before and after hip or knee arthroplasty.

The impact of hip and knee arthroplasty based on the patients' own evaluations of their health, quality of life, and physical ability was assessed using a cross-sectional study design. The eligibility criteria were a diagnosis of primary arthrosis, primary operation, and total joint arthroplasty. Preoperative hip and knee patient groups were compared with similar groups who underwent arthroplasty 2 or 5 years previously. Subjective health outcome was assessed with the Nottingham health profile and a 15-dimensional, health-related quality of life measure. Patients' physical ability was assessed using a measure of activities of daily living. Major improvements were observed for pain, sleep, range of motion, and physical ability. However, after surgery, patients were less healthy than the general population of the same age. The health status of patients operated on 2 or 5 years ago was similar, suggesting that health gains persist for several years.

Activities of Daily Living↗