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Dive into the research topics where Jon Karlsson is active.

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Featured researches published by Jon Karlsson.


Sports Medicine | 1999

Patellofemoral pain syndrome: a review of current issues.

Roland Thomeé; Jesper Augustsson; Jon Karlsson

AbstractThere is no clear consensus in the literature concerning the terminology, aetiology and treatment for pain in the anterior part of the knee. The term ‘anterior knee pain’ is suggested to encompass all pain-related problems. By excluding anterior knee pain due to intra-articular pathology, peripatellar tendinitis or bursitis, plica syndromes, Sinding Larsen’s disease,Osgood Schlatter’s disease, neuromas and other rarely occurring pathologies, it is suggested that remaining patients with a clinical presentation of anterior knee pain could be diagnosed with patello-femoral pain syndrome (PFPS). Three major contributing factors of PFPS are discussed: (i) malalignment of the lower extremity and/or the patella; (ii) muscular imbalance of the lower extremity; and (iii) overactivity.The significance of lower extremity alignment factors and pathological limits needs further investigation. It is possible that the definitions used for malalignment should be re-evaluated, as the scientific support is very weak for determining when alignment is normal and when there is malalignment. Consequently, pathological limits must be clarified, along with evaluation of risk factors for acquiring PFPS.Muscle tightness and muscular imbalance of the lower extremity muscles with decreased strength due to hypotrophy or inhibition have been suggested, but remain unclear as potential causes of PFPS. Decreased knee extensor strength is a common finding in patients with PFPS. Various patterns of weaknesses have been reported, with selective weakness in eccentric muscle strength, within the quadriceps muscle and in terminal knee extension. The significance of muscle function in a closed versus open kinetic chain has been discussed, but is far from well investigated. It is clear that further studies are necessary in order to establish the significance of various strength deficits and muscular imbalances, and to clarify whether a specific disturbance in muscular activation is a cause or an effect (or both) of PFPS.The most common symptoms in patients with PFPS are pain during and after physical activity, during bodyweight loading of the lower extremities in walking up/down stairs and squatting, and in sitting with the knees flexed. However, the source of patello-femoral pain in patients with PFPS cannot be sufficiently explained. There are several types of clinical manifestation of pain, and therefore a differentiated documentation of the patient’s pain symptoms is necessary. The connection between strength, pain and inhibition, as well as between personality and pain, needs further investigation.Many different treatment protocols are described in the literature and recent studies advocate a comprehensive treatment approach allowing for an individual and specifically designed treatment. Surgical treatment is rarely indicated.It is strongly suggested that, when presenting studies on PFPS, a detailed description should be provided of the diagnosis, inclusion and exclusion criteria of the patients should be specified along with a detailed methodology, and the conclusions drawn should be compared with those of other studies in the published literature. As this is not the case in most studies on PFPS found in the literature, it is only possible to make general comparisons. In order to further develop treatment models for PFPS we advocate prospective, randomised, controlled, long term studies using validated outcome measures. However, there is a strong need for basic research on the nature and aetiology of PFPS in order to better understand this mysterious syndrome.


Foot & Ankle International | 2001

Validation of the foot and ankle outcome score for ankle ligament reconstruction.

Ewa M. Roos; Sveinbjörn Brandsson; Jon Karlsson

We studied the validity and reliability of the Foot and Ankle Outcome Score (FAOS) when used to evaluate the outcome of 213 patients (mean age 40 years, 85 females) who underwent anatomical reconstruction of the lateral ankle ligaments with an average postoperative follow-up of 12 years (range, three to 24 years). The FAOS is a 42-item questionnaire assessing patient-relevant outcomes in five separate subscales (Pain, Other Symptoms, Activities of Daily Living, Sport and Recreation Function, Foot- and Ankle-Related Quality of Life). The FAOS met set criteria of validity and reliability. The FAOS appears to be useful for the evaluation of patient-relevant outcomes related to ankle reconstruction.


Journal of Bone and Joint Surgery, American Volume | 1988

Reconstruction of the lateral ligaments of the ankle for chronic lateral instability.

Jon Karlsson; Tommy Bergsten; Olle Lansinger; Lars Peterson

One hundred and seventy-six patients (180 ankles) who had chronic lateral instability of the ankle were treated with transection and imbrication of the anterior talofibular ligament. Sixty-eight of the ankles had reconstruction of the calcaneofibular ligament as well. Of the 176 patients, 148 (152 ankles) were available for follow-up, which ranged from two to twelve years (mean, six years). An excellent or good result was achieved in 132 ankles, all of which had improved mechanical stability as measured radiographically. Sixteen of the twenty ankles that had an unsatisfactory result were in patients who had generalized hypermobility of the joints or long-standing local ligamentous insufficiency, or both, or who had had a previous operation. Reconstruction of both ligaments gave a better functional result than when only the anterior talofibular ligament was reconstructed.


American Journal of Sports Medicine | 1992

The effect of external ankle support in chronic lateral ankle joint instability An electromyographic study

Jon Karlsson; Gunnar Andréasson

We examined the effect of ankle taping on ankle joint stability by measuring mechanical stability using stand ardized stress radiographs. Anterior talar translation and talar tilt, both with and without ankle tape, were examined. The reduction of anterior talar translation and talar tilt with tape as compared to without tape was insignificant. The reaction time of the peroneus muscles was measured by electromyographic signal after a simulated ankle sprain on a tilting trapdoor. The reaction time was significantly slower in the unstable ankles of 20 athletes with unilateral ankle instability than in the stable contra lateral ankles. With tape, the reaction time was signifi cantly shortened, although not back to normal. The greatest improvement in reaction time was achieved in ankles with the highest degree of mechanical instability. Thus, the mechanism behind the function of ankle tape may be to restrict the extremes of ankle motion and to help shorten the reaction time of the peroneus muscles by affecting the proprioceptive function of the ankle.


Journal of Bone and Joint Surgery-british Volume | 2001

Acute rupture of tendo Achillis: A PROSPECTIVE, RANDOMISED STUDY OF COMPARISON BETWEEN SURGICAL AND NON-SURGICAL TREATMENT

Michael Möller; T. Movin; H. Granhed; K. Lind; E. Faxén; Jon Karlsson

In a prospective, randomised, multicentre study, 112 patients (99 men and 13 women, aged between 21 and 63 years) with acute, complete rupture of tendo Achillis were allocated either to surgical treatment followed by early functional rehabilitation, using a brace, or to non-surgical treatment, with plaster splintage for eight weeks. The period of follow-up was for two years. Evaluation was undertaken by independent observers and comprised interviews, clinical measurements, isokinetic muscle performance tests, heel-raise tests and an overall outcome score. The rate of rerupture was 20.8% after non-surgical and 1.7% after surgical treatment (p < 0.001). Surgical and non-surgical treatment produced equally good functional results if complications were avoided. However, the rate of rerupture after non-surgical treatment was unacceptably high.In a prospective, randomised, multicentre study, 112 patients (99 men and 13 women, aged between 21 and 63 years) with acute, complete rupture of tendo Achillis were allocated either to surgical treatment followed by early functional rehabilitation, using a brace, or to non-surgical treatment, with plaster splintage for eight weeks. The period of follow-up was for two years. Evaluation was undertaken by independent observers and comprised interviews, clinical measurements, isokinetic muscle performance tests, heel-raise tests and an overall outcome score. The rate of rerupture was 20.8% after non-surgical and 1.7% after surgical treatment (p < 0.001). Surgical and non-surgical treatment produced equally good functional results if complications were avoided. However, the rate of rerupture after non-surgical treatment was unacceptably high.


Scandinavian Journal of Medicine & Science in Sports | 2001

Eccentric overload training for patients with chronic Achilles tendon pain – a randomised controlled study with reliability testing of the evaluation methods

K. Grävare Silbernagel; Roland Thomeé; Pia Thomeé; Jon Karlsson

The purpose was to examine the reliability of measurement techniques and evaluate the effect of a treatment protocol including eccentric overload for patients with chronic pain from the Achilles tendon. Thirty‐two patients with proximal achillodynia (44 involved Achilles tendons) participated in tests for reliability measures. No significant differences and strong (r=0.56–0.72) or very strong (r=0.90–0.93) correlations were found between pre‐tests, except for the documentation of pain at rest (P<0.008, r=0.45). To evaluate the effect of a 12‐week treatment protocol for patients with chronic proximal achillodynia (pain longer than three months) 40 patients (57 involved Achilles tendons) with a mean age of 45 years (range 19–77) were randomised into an experiment group (n=22) and a control group (n=18). Evaluations were performed after six weeks of treatment and after three and six months. The evaluations (including the pre‐tests), performed by a physical therapist unaware of the group the patients belonged to, consisted of a questionnaire, a range of motion test, a jumping test, a toe‐raise test, a pain on palpation test and pain evaluation during jumping, toe‐raises and at rest. A follow‐up was also performed after one year. There were no significant differences between groups at any of the evaluations, except that the experiment group jumped significantly lower than the control group at the six‐week evaluation. There was, however, an overall better result for the experiment group with significant improvements in plantar flexion, and reduction in pain on palpation, number of patients having pain during walking, having periods when asymptomatic and having swollen Achilles tendon. The controls did not show such changes. Furthermore, at the one‐year follow‐up there were significantly more patients in the experiment group, compared with the control group, that were satisfied with their present physical activity level, considered themselves fully recovered, and had no pain during or after physical activity. The measurement techniques and the treatment protocol with eccentric overload used in the present study can be recommended for patients with chronic pain from the Achilles tendon.


Knee Surgery, Sports Traumatology, Arthroscopy | 1999

Complications following arthroscopic anterior cruciate ligament reconstruction. A 2-5-year follow-up of 604 patients with special emphasis on anterior knee pain.

J. Kartus; Lennart Magnusson; Sven Stener; Sveinbjörn Brandsson; Bengt I. Eriksson; Jon Karlsson

Abstract The aim of the study was to assess knee function after arthroscopic anterior cruciate ligament reconstruction and to analyse complications impeding rehabilitation, additional surgery until the final follow-up, as well as residual patellofemoral pain and donor-site problems. Between 1991 and 1994, 635 patients were operated on using patellar tendon autografts and interference screw fixation. Of these, 604 (95.1%) patients (403 male and 201 female) were re-examined by independent observers at the final follow-up 38 (range 21–68) months post-operatively. The Lysholm score was 85 (range 14–100) points and the Tegner activity level was 6 (range 1–10). Using the IKDC score, 206 patients (34.1%) were classified as normal, 244 (40.4%) as nearly normal, 122 (20.2%) as abnormal and 32 (5.3%) as severely abnormal. In patients with an uninjured contralateral knee (n = 527), the KT-1000 revealed a total side-to-side difference of 1.5 (range –7–11) mm, and 384/527 (72.9%) had a side-to-side difference of ≤ 3 mm. The one-leg-hop test was 95% (range 0%–167%). One or more complications impeding rehabilitation were recorded in 184/604 patients (30.5%). The most common was an extension deficit (> 5°), in 81 patients (13.4%). During the period until the final follow-up, 196 re-operations were performed in 161/604 (26.7%) patients. More than one re-operation was required in 27 patients. Shaving and anterior scar resection due to extension deficit were the most common procedures performed (on 65 occasions). Moderate to severe subjective anterior knee pain related to activity, walking up and down stairs, and sitting with the knee flexed was found in 203/604 patients (33.6%). The median loss of anterior knee sensitivity was 16 (range 0–288) cm2. Patients with a full range of motion had less anterior knee pain than patients with isolated flexion or extension deficits, or combined flexion and extension deficits (P < 0.05, P = 0.08 and P < 0.001, respectively). Patients with a full range of motion had less anterior knee pain than patients with extension deficits (with and without flexion deficits) (P < 0.001). Patients with a full range of motion and a minimal loss (≤ 4 cm2) of anterior knee sensitivity had significantly (P < 0.01) less subjective anterior knee pain than patients who did not fulfil these criteria. A considerable number of complications hindering the rehabilitation and conditions requiring additional surgery until the final follow-up were recorded. Anterior knee pain and problems with knee-walking were correlated with the loss of range of motion and anterior knee sensitivity.


American Journal of Sports Medicine | 2007

The Achilles Tendon Total Rupture Score (ATRS) Development and Validation

Katarina Nilsson-Helander; Roland Thomeé; Karin Gravare-Silbernagel; Pia Thomeé; Eva Faxén; Bengt I. Eriksson; Jon Karlsson

Background There is a need for a patient-relevant instrument to evaluate outcome after treatment in patients with a total Achilles tendon rupture. Purpose To develop and validate a new patient-reported instrument for measuring outcome after treatment for total Achilles tendon rupture. Study Design Cohort study (diagnosis); Level of evidence, 1. Methods Development of this instrument consisted of item generation and test construction, item reduction, validation, evaluation of structure and internal consistency, test-retest, and test for responsiveness. The final version, the Achilles tendon Total Rupture Score (ATRS), was tested for validity, structure, and internal consistency (Cronbachs alpha) on 82 patients and 52 healthy persons. A correlation analysis was performed of the ATRS with the 2 validated foot/ankle/Achilles tendon scores, the Foot and Ankle Outcome Score (FAOS) and the Swedish version of the Victorian Institute of Sports Assessment-Achilles questionnaire (VISA-A-S). Structure was evaluated with factor analysis. Test-retest reliability was evaluated on 43 patients. The ATRS responsiveness was tested on 43 patients by calculating the effect size. Results The total score for the patients ranged from 17 to 100 with a mean (median) of 77 (85) and a standard deviation (interquartile range) of 21.4 (23). A significantly (P < .0001) higher total score was found for the healthy subjects, ranging from 94 to 100 with a mean (median) of 99.8 (100) and a standard deviation (interquartile range) of 1.1 (0). The ATRS correlated significantly (P < .01) with all subscales of the FAOS (r = 0.60-0.84) and the VISA-A-S (r = 0.78). The factor analysis gave 1 factor of importance. The internal consistency was 0.96 as measured with Cronbachs alpha. The test-retest produced an intraclass correlation coefficient of 0.98. The tests for responsiveness showed an effect size between 0.87 and 2.21. Conclusion The ATRS is a patient-reported instrument with high reliability, validity, and sensitivity for measuring outcome after treatment in patients with a total Achilles tendon rupture. Clinical Relevance The ATRS is a self-administered instrument with high clinical utility, and we suggest the score for measuring the outcome, related to symptoms and physical activity, after treatment in patients with a total Achilles tendon rupture.


American Journal of Sports Medicine | 2012

The Swedish National Anterior Cruciate Ligament Register A Report on Baseline Variables and Outcomes of Surgery for Almost 18,000 Patients

Mattias Ahldén; Kristian Samuelsson; Ninni Sernert; Magnus Forssblad; Jon Karlsson; Jüri Kartus

Background: The Swedish National Anterior Cruciate Ligament Register provides an opportunity for quality surveillance and research. Purpose: The primary objective was to recognize factors associated with a poorer outcome at an early stage. Study Design: Case series; Level of evidence, 4. Methods: Registrations are made using a web-based protocol with 2 parts: a patient-based section with self-reported outcome scores and a surgeon-based section, where factors such as cause of injury, previous surgery, time between injury and reconstruction, graft selection, fixation technique, and concomitant injuries are reported. The self-reported outcome scores are registered preoperatively and at 1, 2, and 5 years. Results: Approximately 90% of all anterior cruciate ligament (ACL) reconstructions performed annually in Sweden are reported in the register. Registrations during the period 2005-2010 were included (n = 17,794). After excluding multiligament reconstructions and reoperations, the male:female ratio was 57.5:42.5 for both primary (n = 15,387) and revision (n = 964) surgery. The cause of injury was soccer in approximately half the male patients and in one third of the female patients. All subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) were significantly improved 1, 2, and 5 years postoperatively in patients undergoing primary reconstructions. In terms of the KOOS, revisions did significantly less well than primary reconstructions on all follow-up occasions, and smokers fared significantly less well than nonsmokers both preoperatively and at 2 years. Patients who had concomitant meniscal or chondral injuries at reconstruction did significantly less well preoperatively and at 1 year in terms of most KOOS subscales compared with patients with no such injuries. At 5 years, a significant difference was only found in terms of the sport/recreation subscale. Double-bundle reconstructions revealed no significant differences in terms of all the KOOS subscales at 2 years compared with single-bundle reconstructions (114 double-bundle vs 5109 single-bundle). During a 5-year period, 9.1% (contralateral, 5.0%; revision, 4.1%) of the patients underwent a contralateral ACL reconstruction or revision reconstruction of the index knee. The corresponding figure for 15- to 18-year-old female soccer players was 22.0%. Conclusion: Primary ACL reconstruction significantly improves all the subscales of the KOOS. Young female soccer players run a major risk of reinjuring their ACL or injuring the contralateral ACL; revision ACL reconstructions do less well than primary reconstructions, and smokers do less well than nonsmokers.


American Journal of Sports Medicine | 2010

Acute Achilles Tendon Rupture A Randomized, Controlled Study Comparing Surgical and Nonsurgical Treatments Using Validated Outcome Measures

Katarina Nilsson-Helander; Karin Grävare Silbernagel; Roland Thomeé; Eva Faxén; Nicklas Olsson; Bengt I. Eriksson; Jon Karlsson

Background There is no consensus regarding the optimal treatment for patients with acute Achilles tendon rupture. Few randomized controlled studies have compared outcomes after surgical or nonsurgical treatment with both groups receiving early mobilization. Purpose This study was undertaken to compare outcomes of patients with acute Achilles tendon rupture treated with or without surgery using early mobilization and identical rehabilitation protocols. Study Design Randomized, controlled trial; Level of evidence, 1. Methods Ninety-seven patients (79 men, 18 women; mean age, 41 years) with acute Achilles tendon rupture were treated and followed for 1 year. The primary end point was rerupturing. Patients were evaluated using the Achilles tendon Total Rupture Score (ATRS), functional tests, and clinical examination at 6 and 12 months after injury. Results There were 6 (12%) reruptures in the nonsurgical group and 2 (4%) in the surgical group (P = .377). The mean 6- and 12-month ATRS were 72 and 88 points in the surgical group and 71 and 86 points in the nonsurgical group, respectively. Improvements in ATRS between 6 and 12 months were significant for both groups, with no significant between-group differences. At the 6-month evaluation, the surgical group had better results compared with the nonsurgically treated group in some of the muscle function tests; however, at the 12-month evaluation there were no differences between the 2 groups except for the heel-rise work test in favor of the surgical group. At the 12-month follow-up, the level of function of the injured leg remained significantly lower than that of the uninjured leg in both groups. Conclusion The results of this study did not demonstrate any statistically significant difference between surgical and nonsurgical treatment. Furthermore, the study suggests that early mobilization is beneficial for patients with acute Achilles tendon rupture whether they are treated surgically or nonsurgically. The preferred treatment strategy for patients with acute Achilles tendon rupture remains a subject of debate. Although the study met the sample size dictated by the authors’ a priori power calculation, the difference in the rerupture rate might be considered clinically important by some.

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Dive into the Jon Karlsson's collaboration.

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Bengt I. Eriksson

Sahlgrenska University Hospital

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Roland Thomeé

University of Gothenburg

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Jüri Kartus

University of Gothenburg

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Volker Musahl

University of Pittsburgh

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Leif Swärd

Sahlgrenska University Hospital

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Roland Becker

Otto-von-Guericke University Magdeburg

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Freddie H. Fu

University of Pittsburgh

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Ninni Sernert

University of Gothenburg

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