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Biomedical subjects

T Wredmark

Publications and source records attributed to T Wredmark.

At least 19 recordsLinked to original sources
PubMed2003

Training in tasks with different visual-spatial components does not improve virtual arthroscopy performance.

BACKGROUND: We earlier showed that training in the Procedicus KSA Simulator improves the performance of tasks done later in the same simulator. However, it is still unclear how performance in a specific visual-spatial simulator context may change after training in other simulators with different visual-spatial components. In particular, the aim of this study was to test whether performance in the Procedicus Virtual Arthroscopy (VA) Knee Simulator would remain unchanged after a training session in three other simulators with different visual-spatial components. METHODS: Twenty-eight medical students participated in a quasi-transfer study. They were randomly allocated to an experimental group ( n = 14) and a control group ( n = 14). RESULTS: Performance in the Procedicus VA Knee Simulator did not improve after training in other simulators with different visual-spatial components ( t-test p = NS). No significant correlation was found between the Procedicus VA Knee and the Minimally Invasive Surgical Trainer (MIST) simulators. CONCLUSION: One hour of training in different visual-spatial contexts was not enough to improve the performance in virtual arthroscopy tasks. It cannot be excluded, however, that experienced trainees could improve their performance, because perceived similarity between different situations is influenced by many psychological factors, such as the knowledge or expertise of the person performing the transfer task.

Adult↗
PubMed2002

Validation and learning in the Procedicus KSA virtual reality surgical simulator.

BACKGROUND: Advanced simulator training within medicine is a rapidly growing field. Virtual reality simulators are being introduced as cost-saving educational tools, which also lead to increased patient safety. METHODS: Fifteen medical students were included in the study. For 10 medical students performance was monitored, before and after 1 h of training, in two endoscopic simulators (the Procedicus KSA with haptic feedback and anatomical graphics and the established MIST simulator without this haptic feedback and graphics). Five medical students performed 50 tests in the Procedicus KSA in order to analyze learning curves. One of these five medical students performed multiple training sessions during 2 weeks and performed more than 300 tests. RESULTS: There was a significant improvement after 1 h of training regarding time, movement economy, and total score. The results in the two simulators were highly correlated. CONCLUSION: Our results show that the use of surgical simulators as a pedagogical tool in medical student training is encouraging. It shows rapid learning curves and our suggestion is to introduce endoscopic simulator training in undergraduate medical education during the course in surgery when motivation is high and before the development of "negative stereotypes" and incorrect practices.

Computer Simulation↗
PubMed2002

Ultrasound-guided percutaneous biopsies of the semitendinosus muscle following ACL reconstruction--a methodological description.

PURPOSE: To evaluate whether the ultrasound-guided biopsy technique could be used to analyse the histochemical profile of m. semitendinosus following ACL reconstruction with autologous semitendinosus tendon graft. MATERIAL AND METHODS: Sixteen patients were included in the study. During ACL surgery, specimens from m. semitendinosus were obtained via open biopsy. Ultrasound-guided biopsies from m. semitendinosus were performed 7 - 11 months postoperatively from operated leg (n = 16) and non-operated leg (n = 8). RESULTS: Two biopsy samples were pooled and formed a specimen of approximately 150 fibres. For fibre type composition, there was correlation between open biopsy and ultrasound-guided biopsy data, (P = 0.003, r = 0.89). The r-value for mean fibre area was 0.72 (P = 0.06). The methodological error for fibre type 1 % and mean fibre area was 9 %. Postoperatively, no significant differences were found in fibre type composition or fibre type areas between the operated and non-operated leg. CONCLUSION: Ultrasound-guided biopsy is an easy and safe technique that can be used for scientific studies and in clinical practice where biopsy from small muscles or from special location in muscles, such as in ruptures, scars or others is needed.

Adolescent↗
PubMed2002

Observer reliability in the arthroscopic classification of osteoarthritis of the knee.

We studied 19 videotaped knee arthroscopies in 19 patients with mild to moderate osteoarthritis (OA) of the knee in order to compare the intraobserver and interobserver reliability and the patterns of disagreement between four orthopaedic surgeons. The classifications of OA of Collins, Outerbridge and the French Society of Arthroscopy were used. Intraobserver and interobserver agreements using kappa measures were 0.42 to 0.66 and 0.43 to 0.49, respectively. Only 6% to 8% of paired intraobserver classifications differed by more than one category. Observer-specific disagreement was evident both within and between observers. A small, but significant, occasional variation was also seen. Although reliability may improve by an analysis of disagreement, it appears that the arthroscopic grading of early osteoarthritic lesions is inexact.

Adult↗
PubMed2002

In vivo physiological changes in the synovial membrane of the knee during reperfusion after arthroscopy. A study using the microdialysis technique.

We have used in vivo microdialysis to monitor postoperative physiological events in the synovial membrane after arthroscopy. The levels of lactate were significantly higher in the synovial membrane than in the reference tissue (subcutaneous fat) and there was a significant increase in lactate after operation. Blood flow, measured as the ethanol ratio, was stable in both tissues. Our findings show that there was an increase in the local production of lactate since the levels of lactate in blood and the reference tissue were comparable and did not show a significant increase. There was also a consumption of glucose in the synovial membrane which was not observed in the reference tissue. The levels of pyruvate were higher in the synovial membrane. A state of reperfusion occurs in the synovial membrane after moderate trauma such as standard arthroscopy of the knee. Microdialysis should be further evaluated in studies of the in vivo physiology of the synovial membrane.

Adipose Tissue↗
PubMed2001

[Simulator training in medicine and health care. A new pedagogic model for good patient safety].

Advanced simulation within medicine and health care is a rapidly growing field. Simulator based training can be applied in minimal invasive surgery, in endoscopic procedures as well as in anaesthesia and critical care management. At Huddinge University Hospital a center for advanced simulation of both endoscopic surgery and anaesthesia/critical care management is currently being set up. The objective is to focus on improved medical and health care training and thus improving patient safety by reducing medical errors.

Anesthesiology↗
PubMed2001

Semitendinosus muscle in anterior cruciate ligament surgery: Morphology and function.

PURPOSE: To evaluate the fate of the hamstring muscles in general and the semitendinosus muscle in particular, after anterior cruciate ligament (ACL) reconstruction with an autologous semitendinosus tendon graft from the ipsilateral side. TYPE OF STUDY: Prospective consecutive case series investigation. METHODS: Included were 16 consecutive patients, 14 male and 2 female, with a mean age of 26 years. The inclusion criterion was chronic unilateral ACL insufficiency with no concomitant knee ligament injuries. ACL reconstruction was performed with a quadruple semitendinosus tendon graft using the EndoButton technique (Acufex, Mansfield, MA). Intraoperatively, muscle specimens were taken from the semitendinosus muscle on the harvested side. Follow-up at a minimum of 6 months included clinical examination, isokinetic strength performance, magnetic resonance imaging (MRI) of the thigh and knee, and ultrasound-guided muscle biopsy procurement from the semitendinosus muscle for histochemical and enzymatic analyses. RESULTS: Of the patients, 75% showed regeneration of their semitendinosus tendons. The neotendons all inserted below the knee joint where they had fused with the gracilis tendon to a conjoined tendon inserting in the pes anserinus. The semitendinosus muscle had a smaller cross-sectional area on the operated side but none showed total atrophy. Less atrophy was present in the patients with a regenerated semitendinosus neotendon compared with those without regeneration (P =.029). In the latter group the semimembranosus muscle seemed to compensate for this with hypertrophy (P =.019). Cross-sectional muscle fiber areas, the relative number of each fiber type and oxidative potential as estimated by citrate synthase activity, showed no significant differences between the operated and nonoperated legs. The isokinetic strength of the hamstrings and quadriceps was significantly lower in the operated leg than in the nonoperated leg. CONCLUSIONS: With this surgical technique, the semitendinosus muscle can recover and the tendon has, according to the MRI images, a great potential to regenerate after its removal.

Adolescent↗
PubMed2001

The semitendinosus tendon regenerates after resection: a morphologic and MRI analysis in 6 patients after resection for anterior cruciate ligament reconstruction.

Recently, the surprising observation has been made, supported by clinical and MRI findings, that the semitendinosus tendon can regenerate after being harvested in its whole length and thickness for anterior cruciate ligament reconstruction. We studied 6 patients with previous anterior cruciate ligament reconstruction, using a quadruple semitendinosus tendon autograft. In 5 of these, physical examination and MRI showed that the tendond had regenerated. In all 6 patients, the findings were documented macroscopically by open surgical exploration and in the 5 regenerated tendons, also morphologically by biopsies. Macroscopically, histologically and immunohistochemically the regenerated tendons closely resembled normal ones with focal scar-like areas. Our present findings and earlier studies show that full length and thickness harvesting of the semitendinosus tendon in most cases result in full-length tendon regeneration with tissue closely resembling the normal tendon.

Adolescent↗
PubMed2001

A comparison of quadruple semitendinosus and patellar tendon grafts in reconstruction of the anterior cruciate ligament.

In a two-centre study, 164 patients with unilateral instability of the anterior cruciate ligament were prospectively randomised to arthroscopic reconstruction with either a patellar tendon graft using interference screw fixation or a quadruple semitendinosus graft using an endobutton fixation technique. The same postoperative rehabilitation protocol was used for all patients and follow-up at a median of 31 months (24 to 59) was carried out by independent observers. Four patients (2%) were lost to follow-up. No significant differences were found between the groups regarding the Stryker laxity test, one-leg hop test, Tegner activity level, Lysholm score, patellofemoral pain score, International Knee Documentation Committee (IKDC) score or visual analogue scale, reflecting patient satisfaction and knee function. Slightly decreased extension, compared with the non-operated side, was found in the patellar tendon group (p < 0.05). Patients with associated meniscal injuries had lower IKDC, visual analogue (p < 0.01) and Lysholm scores (p < 0.05) than those without such injuries. Patients in whom reconstruction had been carried out less than five months after the injury had better final IKDC scores than the more chronic cases (p < 0.05). We conclude that patellar tendon and quadruple semitendinous tendon grafts have similar outcomes in the medium term. Associated meniscal pathology significantly affects the final outcome and early reconstruction seems to be beneficial.

Adult↗
PubMed2001

There are differences in early morbidity after ACL reconstruction when comparing patellar tendon and semitendinosus tendon graft. A prospective randomized study of 107 patients.

The main objective of this study was to study solely early postoperative morbidity following anterior cruciate ligament (ACL) reconstruction by comparing the gold standard procedure, the bone-patellar tendon-bone graft (BTB), and one of the most common alternatives, the semitendinosus tendon graft (ST). The prospective study included 107 randomized patients (50 BTB and 57 ST). The follow-up period was set to 20-35 weeks postoperatively (mean 26.8 +/- 3.5 weeks). One patient suffered early graft rupture and 89 (84%) of the remaining 106 patients were able to attend the follow-up within the given time limit. There were no differences in sick leave between the groups. The Lysholm score, Tegner activity level score and Visual Analog Scales (VAS) with the questions "How does your knee function?" and "How does your knee affect your activity level?" revealed no differences between the groups. Subjective patellofemoral pain, patellofemoral compartment findings and donor site morbidity were more common in the BTB group, P < 0.05. Lachman test grade 1+ was more common in the ST group, P < 0.05, but there was no significant difference in instrumented Lachman side-to-side comparison. The ST group scored better in the one-leg hop test than the BTB group, P < 0.05. No correlations between these clinical and functional findings and subjective knee function scores were found. In conclusion, ACL reconstruction with ST tendon graft presented fewer short-term postoperative problems as compared to reconstruction with BTB.

Adolescent↗
PubMed1999

Early influence of an ankle sprain on objective measures of ankle joint function. A prospective randomised study of ankle brace treatment.

The purpose of this study was to analyse objective modalities of ankle joint function after an acute ankle sprain and to see whether treatment with an air-cushioned ankle brace could enhance the restoration of function compared with a traditionally used compression bandage. The study included 73 consecutive patients between 15 and 55 years of age with an acute grade II or III ankle sprain, who sought medical care within 24 h of the time of injury. Patients with recurrent sprain were excluded. The patients were allocated at random to treatment with compression bandage or an air-cushioned ankle brace (Air-Stirrup, Aircast). The regimen included early motion and weight-bearing in both groups. The patients were examined initially within 24 h, after 3-5 days, 2, 4 and 10 weeks after the injury by the following tests: clinical examination including range of motion, recording of postural sway by stabilometry, joint position sense test, isokinetic eversion-inversion muscle torques and figure-of-eight running. A decreased active range of motion in eversion-inversion was observed during the entire follow-up period. Increased postural sway was registered when standing on the injured foot up to 4 weeks after the injury, as were a deficit in evertor muscle peak torque and an evertor-invertor muscle imbalance compared with the uninjured side. Women demonstrated a greater impairment in postural sway than men. A longer curve running time with the injured ankle at the outside of the curve was noted at the 10-week follow-up. With the exception of running in a figure of eight, these measures were not influenced by treatment with a semi-rigid ankle brace. The methods used in the present study are well suited for further studies of objective modalities of ankle joint function, with the possible exception of the joint position sense test.

Ankle Injuries↗
PubMed1999

Semitendinosus tendon regeneration after harvesting for ACL reconstruction. A prospective MRI study.

Utilisation of the semitendinosus and gracilis tendons in reconstruction of the anterior cruciate ligament (ACL) has become more common during the last few years. In recent studies a regeneration potential in the harvested tendons has been observed. In this study, 11 consecutive patients who underwent ACL reconstruction with a quadruple semitendinosus graft were examined 6-12 months postoperatively by MRI. Another two patients were examined within 2 weeks after surgery. The median age of the patients was 24 years and there were 8 males and 3 females. The right knee was involved in six patients and the left knee in five. A low-field 0.2 Tesla Siemens open MRI was used for examinations and T1 and T2 weighted transaxial sequences over the thigh and the knee joint were performed. In some instances, additional sagittal sequences were used. ROI analysis of the pixel value of the signal and area determinations on transaxial sequences was performed for both the involved and the healthy side. In 8 of the 11 patients examined 6-12 months postoperatively, a regeneration of the semitendinosus tendon with normal anatomical topographies to the level of the tibial plateau was found. Three of these eight patients were analysed more distally and fusion of the semitendinosus and gracilis tendons was found approximately 30 mm below the joint line before they inserted as a "conjoined tendon" into the pes anserinus. At the mid-thigh level, the semitendinosus muscle had a smaller area and a higher signal than that on the normal side. However, this difference was smaller in the patients showing normal distal tendon regeneration. This study indicates that the semitendinosus tendon has a strong potential for regeneration and that the muscle atrophy seems to be less in the patients with a more normalised distal insertion of the tendon in the pes anserinus.

Adult↗
PubMed1998

Tensile properties of the knee-joint capsule at an elevated intraarticular pressure.

In order to evaluate the capsular reaction to high intraarticular pressure (IAP) in the knee during arthroscopy, we examined 13 patients admitted for elective surgery with joint infusion to 30, 70, 120 and 170 mmHg IAP (4, 9.3, 16 and 22.7 kPa). The infusion was repeated once, at all IAP levels except 30 mmHg, after 2 min and was recorded for another 2 min. A pressure-time curve was recorded as a combined effect of viscoelastic properties of the capsule and extraarticular fluid absorption. 3 more knee joints were infused directly to 170 mmHg and a pressure-time curve was recorded for 15 min, after which time the joint was reinfused to 170 mmHg in order to estimate the change in joint volume due to absorption or relaxation. In 10 knees, the curves were uniform. At infusion, the pressure curve was almost linear above 70 mmHg. There were no signs of plastic deformation of the joint capsule at pressures below 120 mmHg, while at 170 mmHg there were signs of capsular deformation. At each pressure level, the curve revealed a rapid fall in initial pressure that gradually decreased because of capsular relaxation or fluid absorption. Repeated infusion delayed the fall in pressure, due to increased capsular stiffness. In 3 knees infused directly to 170 mmHg IAP, the slope for the first 2 min of the pressure-time curve did not differ from that found at maximal IAP in knees examined with stepwise increasing pressures. Discontinuity of the capsule, even of puncture size, influenced the pressure/volume correlation considerably. We conclude that at IAP levels of 170 mmHg, there are signs of plastic deformation of the joint capsule. In order to avoid capsular damage, knee arthroscopy should be done at intraarticular pressure levels below 120 mmHg.

Absorption↗
PubMed1998

Function after anterior cruciate ligament injuries. Influence of visual control and proprioception.

Information about limb positions and movements consists of input from visual, vestibular, cutaneous, muscular, tendinous and joint receptors, but the relative contribution from each type and location of receptors is not known. The aim of this study was: a) to measure the contribution from visual control on extremity function, as measured with a one-leg hop test in healthy persons, in patients with an asymptomatic ACL injury, after non-operative treatment and in patients with a stable knee after an ACL reconstruction, b) to investigate if there was any relation between proprioception from the extremity, as measured with the threshold for detecting passive motion of the knee, and the one-leg hop test with a gradual decrease in visual control. There was a decrease in hop-length when the subjects were deprived of visual control that was significant when the dominant eye or both eyes were blinded, both in the 2 patient groups and the reference population. The magnitude of the length reduction did not differ between the groups or between injured and healthy limbs. In all 4 threshold tests performed as a measure of peripheral proprioception, a stronger relation to hop-length was recorded for the blinded hop than with full visual control in the patients with nonoperated ACL injuries. The coefficients of correlation between hop-length and the proprioceptive recordings in the injured limb were of the same magnitude as on the healthy side.

Adult↗
PubMed1997

Insulin-like growth factor I increases bone formation in old or corticosteroid treated rats.

We studied bone induction in subcutaneous implants of demineralized bone matrix with or without insulin-like growth factor I (IGF-I) in aged or corticosteroid-treated rats. Each rat carried one pair of implants, one control and one experiment implant, containing IGF-I dissolved in a hyaluronan solution for slow release. The rats were killed after 3 weeks and the results were evaluated by measuring the calcium content of implants. Young (6-7 weeks) and old (19-27 months) rats were used. A group of young rats was treated for 1 week with subcutaneous injections of 140 micrograms/kg dexamethasone daily. Old rats produced only approximately 1% as much bone as young rats. Local delivery of IGF-I did not increase bone formation in young rats. In old rats, bone formation was increased by IGF-I, 3000 ng/implant. Corticosteroids reduced bone formation in young rats. This effect was partially reversed by local administration of IGF-I.

Age Factors↗
PubMed1996

A prospective controlled randomized study of arthroscopic lavage in acute primary anterior dislocation of the shoulder: one-year follow-up.

Traumatic primary anterior shoulder dislocation has a very high recurrence rate among young people. This has supplied the motivation for studies to find methods of treatment that might become an alternative to traditional therapy. A prospective controlled study was performed to test the hypothesis that acute arthroscopic lavage might have a positive effect on recurrence rate as well as on shoulder stability, range of motion and mobilization. 30 consecutive patients between 18 and 30 years of age were randomized into 2 groups, 1 control group treated conservatively and 1 group treated with acute arthroscopic lavage within 10 days. Clinical examination was made by an independent observer at 1, 6 and 12 months. Results at 6- and 12-month check-ups showed a statistically significantly lower rate of redislocation and a wider range of motion for the group treated with acute arthroscopic lavage. Functional assessment according to the Lysholm shoulder score also indicated better functioning of the joint. Our 1-year follow-up shows very promising and interesting results.

Adult↗
PubMed1996

Ankle arthroscopy under local and general anaesthesia for diagnostic evaluation and treatment.

Improvements in techniques and instrumentation are extending the diagnostic and therapeutic indications for ankle arthroscopy. We aimed to study the diagnostic and therapeutic benefits and complication rate from 112 consecutive ankle arthroscopies performed between 1991 and 1994 under local and general anaesthesia. One-hundred and twelve outpatient ankle arthroscopies were performed in 72 male and 37 female patients, 16-64 years old. The patients were comparable in terms of gender and age in the arthroscopies done under local (n = 69) and the arthroscopies done under general anaesthesia (n = 43). The indications for surgery were pain in 75%, instability in 15%, limited function in 7% and swelling in 4%, and these criteria were similar in both groups. Antero-medial and anterolateral portals were used in all cases. No tourniquet was used and an external distractor was used in one case only. In 64 cases (57%) surgery was performed and included synovectomy, removal of loose bodies, shaving drilling of osteochondritic or other cartilage lesions, resection of impinging osteophytes, fibrosis and meniscoid lesions. In 95 ankles (85%) a definite diagnosis was established. Comparable diagnostic and therapeutic potentials were found between local and general anaesthesia. The complication rate was low. One patient who was operated on under general anaesthesia sustained a deep infection, and three suffered minor superficial nerve injuries. In conclusion, ankle arthroscopy may be performed under local or general anaesthesia with similar diagnostic value and with a low complication rate.

Adolescent↗