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Biomedical subjects

P A Renström

Publications and source records attributed to P A Renström.

At least 19 recordsLinked to original sources
PubMed2001

Ankle ligament injury risk factors: a prospective study of college athletes.

Over two million individuals suffer ankle ligament trauma each year in the United States, more than half of these injuries are severe ligament sprains; however, very little is known about the factors that predispose individuals to these injuries. The purpose of this study was to determine the risk factors associated with ankle injury. We performed a prospective study of 118 Division I collegiate athletes who participated in soccer, lacrosse, or field hockey. Prior to the start of the athletic season, potential ankle injury risk factors were measured, subjects were monitored during the athletic season, and injuries documented. The number of ankle injuries per 1,000 person-days of exposure to sports was 1.6 for the men and 2.2 for the women. There were 13 injuries among the 68 women (19%) and seven injuries among the 50 men (13%), but these proportions were not significantly different. Women who played soccer had a higher incidence of ankle injury than those who played field hockey or lacrosse. Among men, there was no relationship between type of sport and incidence of injury. Factors associated with ankle ligament injury differ for men relative to women. Women with increased tibial varum and calcaneal eversion range of motion are at greater risk of suffering ankle ligament trauma, while men with increased talar tilt are at greater risk. Generalized joint laxity, strength, postural stability, and muscle reaction time were unrelated to injury.

Adult↗
PubMed1999

[Anterior cruciate ligament injuries--still an enormous challenge. Life style-related surgery likely to be used more widely].

Anterior cruciate ligament (ACL) injuries still constitute the greatest single problem in orthopaedic sports medicine. The natural history is not well known. Conservative treatment is appropriate in cases where there are no instability problems, and where activity modifications are acceptable to the patient. However, there is an increased risk of meniscus and cartilage injuries, and thus of arthrosis. The indication for surgery depends on the level of activity, and on whether instability symptoms are present. Arthroscopic surgery of the ACL seems to yield good short-term results in 80-90 per cent of cases. Out-patient ACL surgery is becoming increasingly common. Rehabilitation is often vigorous, with early mobilisation and weight-bearing. Functional range-of-motion and closed kinetic chain exercises predominate. Successful surgical outcome often allows former levels of activity to be resumed. There is still uncertainty as to whether surgery reduces the risk of arthrosis. The nature of the original trauma, and continued top level sports activity may be factors of importance. Further research is needed to elucidate the natural history, and determine the long-term effects of modern ACL surgery.

Anterior Cruciate Ligament↗
PubMed1999

Repair of distal biceps tendon rupture with suture anchors.

We retrospectively evaluated six cases of distal biceps tendon rupture that were treated by a two-incision operative repair using suture anchor attachment to the radial tuberosity for clinical outcome and strength testing. All patients had repair performed by the same surgeon. The average age of the patients, all male, was 43 years (range, 32-57 years). Average time from injury to operative repair was 22 days (range, 9-54 days). Follow-up time averaged 24 months after definitive treatment (range, 11-46 months). At follow-up no patient had limitation of activity and all patients were able to return to their previous employment, although three noted some minor antecubital fossa discomfort. No patient developed a synostosis. Cybex (Medway, Mass.) isokinetic testing revealed elbow flexion strength return for peak torque, total work, and average power, of 107%, 103%, and 110% of the uninjured arm, respectively. Elbow flexion endurance was 2% less in the injured arm. Forearm supination strength measured by peak torque, total work, and average power, was 97%, 85%, and 88% of the uninjured arm, respectively. Forearm supination endurance was 10% less in the injured arm. Our results using suture anchor repair are similar to those previously reported in the literature from bone tunnel repair. Based on our data, we believe that a two-incision repair with suture anchor attachment is a safe and effective method for treatment of distal biceps tendon ruptures.

Adult↗
PubMed1999

Treatment of acute lateral ankle ligament rupture in the athlete. Conservative versus surgical treatment.

Acute lateral ankle ligament sprains are common in young athletes (15 to 35 years of age). Diagnostic and treatment protocols vary. Therapies range from cast immobilisation or acute surgical repair to functional rehabilitation. The lateral ligament complex includes 3 capsular ligaments: the anterior tibiofibular (ATFL), calcaneofibular (CFL) and posterior talofibular (PTFL) ligaments. Injuries typically occur during plantar flexion and inversion; the ATFL is most commonly torn. The CFL and the PTFL can also be injured and, after severe inversion, subtalar joint ligaments are also affected. Commonly, an athlete with a lateral ankle ligament sprain reports having 'rolled over' the outside of their ankle. The entire ankle and foot must be examined to ensure there are no other injuries. Clinical stability tests for ligamentous disruption include the anterior drawer test of ATFL function and inversion tilt test of both ATFL and CFL function. Radiographs may rule out treatable fractures in severe injuries or when pain or tenderness are not associated with lateral ligaments. Stress radiographs do not affect treatment. Ankle sprains are classified from grades I to III (mild, moderate or severe). Grade I and II injuries recover quickly with nonoperative management. A non-operative 'functional treatment' programme includes immediate use of RICE (rest, ice, compression, elevation), a short period of immobilisation and protection with a tape or bandage, and early range of motion, weight-bearing and neuromuscular training exercises. Proprioceptive training on a tilt board after 3 to 4 weeks helps improve balance and neuromuscular control of the ankle. Treatment for grade III injuries is more controversial. A comprehensive literature evaluation and meta-analysis showed that early functional treatment provided the fastest recovery of ankle mobility and earliest return to work and physical activity without affecting late mechanical stability. Functional treatment was complication-free, whereas surgery had serious, though infrequent, complications. Functional treatment produced no more sequelae than casting with or without surgical repair. Secondary surgical repair, even years after an injury, has results comparable to those of primary repair, so even competitive athletes can receive initial conservative treatment. Sequelae of lateral ligament injuries are common. After conservative or surgical treatment, 10 to 30% of patients have chronic symptoms, including persistent synovitis or tendinitis, ankle stiffness, swelling, pain, muscle weakness and 'giving-way'. Well-designed physical therapy programmes usually reduce instability. For individuals with chronic instability refractory to conservative measures, surgery may be needed. Subtalar instability should be carefully evaluated when considering surgery.

Acute Disease↗
PubMed1999

Groin injuries in sport: treatment strategies.

Groin pain in athletes is a common problem that can result in significant amounts of missed playing time. Many of the problems are related to the musculoskeletal system, but care must be taken not to overlook other more serious and potentially life threatening medical cases of pelvis and groin pain. Stress fractures of the bones of the pelvis occur, particularly after a sudden increase in the intensity of training. Most of these stress fractures will heal with rest, but femoral neck stress fractures can potentially lead to more serious problems, and require closer evaluation and sometimes surgical treatment. Avulsion fractures of the apophyses occur through the relatively weaker growth plate in adolescents. Most of these will heal with a graduated physical therapy programme and do not need surgery. Osteitis pubis is characterised by sclerosis and bony changes about the pubic symphysis. This is a self-limiting disease that can take several months to resolve. Corticosteroid injection can sometimes hasten the rehabilitation process. Sports hernias can cause prolonged groin pain, and provide a difficult diagnostic dilemma. In athletes with prolonged groin pain, with increased pain during valsalva manoeuvres and tenderness along the posterior inguinal wall and external canal, an insidious sports hernia should be considered. In cases of true sports hernia, treatment is by surgical reinforcement of the inguinal wall. Nerve compression can occur to the nerves supplying the groin. In cases that do not respond to desensitisation measures, neurolysis can relieve the pain. Adductor strains are common problems in kicking sports such as soccer. The majority of these are incomplete muscle tendon tears that occur just adjacent to, the musculotendinous junction. Most of these will respond to a graduated stretching and strengthening programme, but these can sometimes take a long time to completely heal. Patience is the key to obtain complete healing, because a return to sports too early can lead to chronic pain, which becomes increasingly difficult to treat. Management of groin injuries can be challenging, and diagnosis can be difficult because of the degree of overlap of symptoms between the different problems. By careful history and clinical examination, with judicious use of special tests and good team work, a correct diagnosis can be obtained.

Athletic Injuries↗
PubMed1999

Joint position sense is not changed after acute disruption of the anterior cruciate ligament.

We evaluated the impact of acute, isolated ACL disruption on knee joint proprioception by means of passive-active and active-active joint position sense (JPS) measurement techniques. 18 subjects with acute, isolated and unilateral ACL disruption were tested for JPS in a standing position. The test protocol included 6 trials for each leg. In each trial, the lower leg was passively positioned to an index angle approximating either 30 degrees or 70 degrees, followed by 5 active repetitions of the index angle where the subjects attempted to reproduce the index angle to the best of their ability. The errors from the exact index angle reproduction were calculated as both real (showing both magnitude and direction) and absolute values (only magnitude). All subjects had a tendency to reproduce the index angle with both the injured and normal knees in a more flexed position (overestimation). Only the absolute error produced by the active-active test at flexion angles greater than 45 degrees produced a significant difference with a larger error for the normal knee. In all other comparisons between the injured and the normal knee no differences were found. We conclude that the afferent signals which are compromised by an acute tear of the ACL are insignificant compared to afferent signals from the other joint and muscle receptors.

Acute Disease↗
PubMed1998

Anatomy of the proximal musculotendinous junction of the adductor longus muscle.

Injuries to the adductor longus commonly occur in the proximal part of the muscle tendon unit, close to the insertion site on the pubic bone. Ultrasonography, magnetic resonance imaging (MRI) and surgery have been helpful in localising the lesions, but the exact anatomy of the musculotendinous junction (MTJ) and insertion of the muscle remain unclear. We studied the anatomical features of the MTJ and measured the dimensions of the tendinous insertion into the pubic bone on 37 cadavers: 18 men and 19 women. The medial boundaries were the longest part of the tendon bilaterally in women, while the lateral aspect of the left muscle was greater in men. Tendinous fibres were predominantly found on the anterior surface, while the posterior surface consisted mainly of muscle tissue. The MTJ was clearly demarcated. There were several types of anomalies present which partially explains the difficulty in localising the site of injury and highlights the importance of individualized treatment.

Aged↗
PubMed1998

How can injuries be prevented in the World Cup soccer athlete?

In order to prevent soccer injuries, different risk factors have to be identified as intrinsic (e.g., joint stability or muscle imbalance) and extrinsic (e.g., equipment, turf, and rules risk factors). Some preventive measures are discussed in this article, such as shin guards, prophylactic braces and taping (or both), and proprioceptive training.

Ankle Injuries↗
PubMed1997

Laxity and flexibility of the ankle following reconstruction with the Chrisman-Snook procedure.

The effect of reconstruction of the anterior talofibular ligament with the Chrisman-Snook procedure on neutral zone laxity (anterior-posterior displacement at low loads) and flexibility (a measure of the nonlinear load-displacement response) of the ankle was investigated in vitro during the anterior drawer test. Neutral zone laxity was defined as the magnitude of anterior-posterior displacement of the ankle joint at +/- 2.5 N of applied load. The flexibility parameter was defined as the slope of a line between the natural logarithm of the anterior load applied to the ankle and the resulting displacement. After reconstruction with the Chrisman-Snook procedure, the values for neutral zone laxity of the ankle were significantly less than normal at 0 degree of plantar flexion, whereas the flexibility values were significantly greater than normal. This study revealed that, after the Chrisman-Snook procedure, values for ankle flexibility are not restored to normal even if those for neutral zone laxity are reduced to less than normal. The findings suggest that this nonanatomical reconstruction procedure does not reproduce normal kinematics of the ankle joint. This may help explain some of the adverse clinical reports associated with the Chrisman-Snook reconstruction procedure.

Adolescent↗
PubMed1997

The aging tendon.

After maturation tendons undergo many biochemical, cellular, mechanical and pathological changes that bring about a general decline in the structure and function of the tendon. This decline in the aging tendon is characterized by a reduced ability to adapt to environmental stress and loss of tissue homeostasis. The tendon's adaptability to these changes will decide the rate and the success of treatment of a tendon injury. This review examines these changes and also looks at how we can curtail their progression through exercise and lifestyle modification.

Aging↗
PubMed1997

Diagnosis and treatment of chronic tendon disorders in sports.

Sports and physical activity are becoming more important and more emphasized in the lives of the average person as the health benefits of maintaining an active lifestyle are recognized. In the past most people were primarily active in sports during their time in school. The trend is for more people to continue vigorous activity through middle age and beyond. In addition, as high level athletes continue to reach higher levels of performance more amateur athletes attempt to reach similar levels of intensity, which they may not be able to handle with their level or method of training. This has led to an increase in overuse injuries and chronic tendon injuries. It has been estimated that overuse type injuries account for 30-50% of sports injuries (1).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Subtalar ankle instability. A review.

The aetiology of chronic functional lateral ankle instability is fairly well understood. Pathophysiological factors such as mechanical instability, proprioceptive deficit and peroneal muscle weakness have been demonstrated. Subtalar instability has been in focus during the last years as one of the possible factors behind chronic functional instability of the foot. The exact aetiology and the true incidence of subtalar ligament injuries remain unknown. Most subtalar ligamentous injuries probably occur in combination with injuries of the talo-tibial articulation. Subtalar instability can have the characteristics of chronic lateral instability or recurrent ankle sprains. Patients with chronic subtalar instability typically complain of 'giving way' symptoms and a history of recurrent sprains. Clinical examination including increased inwards rotation and forward displacement of the calcaneus may not be sufficient for the differentiation between ankle and subtalar instability. Radiographic imaging using stress radiographs may be necessary to assess subtalar instability. Subtalar instability can be defined as chronic functional instability with increased values of talar tilt and talo-calcaneal displacement as measured with standardised stress radiographs. Few authors have addressed the treatment of subtalar instability and the condition has not been clearly defined. Subtalar instability can be treated either with a tendon transfer or tenodesis procedure, such as the Chrisman-Snook or triligamentous tenodeses, or with an anatomic ligament reconstruction using the calcaneo-fibular, lateral talo-calcaneal and cervical ligaments combined with a reinforcement of the inferior extensor retinaculum. There have been no studies comparing anatomical and non-anatomical reconstructions and the long term results after ligamentous stabilisation are unknown. The focus of this article is on subtalar instability causing chronic functional ankle instability.

Chronic Disease↗
PubMed1995

Biomechanical analysis of the ankle anterior drawer test for anterior talofibular ligament injuries.

The effect of sectioning the anterior talofibular ligament on the load-displacement behavior of the ankle was evaluated in vitro during the anterior drawer test using the flexibility approach. Controlled forces were applied across the ankle joint in the anterior-posterior direction, and the resulting displacements were measured at four flexion angles (10 degrees of dorsiflexion, neutral, and 10 degrees and 20 degrees of plantar flexion). The anterior talofibular ligament then was sectioned, and the anterior-posterior loadings were repeated at the four flexion angles. Two parameters were developed to describe the nonlinear load-displacement response of the ankle joint: neutral zone laxity (joint displacement between +/- 2.5 N) and flexibility (a measure of the nonlinear load-displacement response of the ankle between 10 and 50 N of anterior drawer loading). After sectioning the anterior talofibular ligament, significant increases in neutral zone laxity were observed at all angles of ankle flexion. The largest increases in neutral zone laxity were found with the ankle in 10 degrees of plantar flexion (76.3% increase) and 20 degrees of plantar flexion (89.7% increase). After sectioning the ligament, a significant increase (19.3%) in flexibility of the ankle was observed at 10 degrees of dorsiflexion, but no change in flexibility was observed with the ankle in the neutral and plantar flexed positions. These findings indicate that anterior drawer testing of the anterior talofibular ligament-deficient ankle between 10 degrees and 20 degrees of plantar flexion results in the largest increase in neutral zone laxity compared with the normal ankle with intact ligaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Ankle arthroscopy.

Ankle arthroscopy is an increasingly useful technique for dealing with a wide range of ankle pathology. Improvements in technique and instrumentation are expanding the range of diagnostic and therapeutic indications for arthroscopy of the ankle. Indications include removal of loose bodies, debridement and drilling of osteochondral defects, relief of anterior tibiotalar impingement, lysis of adhesions and arthrodesis. Reconstruction of lateral ankle instability is currently investigational but may some day be a common procedure. A review of ankle arthroscopy, as well as the currently accepted indications, is presented with a brief review of the literature. The techniques for the most common indications are described. The complications and indications for referral are discussed.

Ankle Injuries↗
PubMed1994

An in vivo comparison between intraoperative isometric measurement and local elongation of the graft after reconstruction of the anterior cruciate ligament.

This study was designed to determine if isometric measurement can be used to predict the pattern of elongation (the change in length) of a bone-patellar ligament-bone graft during passive flexion-extension of the knee at the time of reconstruction of the anterior cruciate ligament in vivo. A standard operative reconstruction technique was performed on nine patients. The tunnel sites for the grafts were selected, and the change in the distance between these sites was measured, with use of a CA-5000 drill-guide isometer as the knee was subjected to passive flexion-extension. After the reconstruction was completed, a Hall-effect transducer was implanted in the graft to measure the local displacement in the mid-substance of the graft that was produced by passive flexion-extension of the knee. For comparison, the isometric measurements and the values for local displacement of the graft were normalized by calculation of the percentage change in the length. With the knee in 10 to 30 degrees of flexion, the average isometric measurements and the measurements of local displacement demonstrated a decrease in length; however, the two techniques of measurement deviated at angles of flexion of 40 degrees and more. On the average, the isometric measurement of elongation between the trial insertion sites predicted that the graft would increase in length in flexion relative to extension, in contrast to the response of the graft after fixation. There was no significant correlation between the isometric measurements and the local elongation of the graft (r2 = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The measurement of elongation of anterior cruciate-ligament grafts in vivo.

Many investigators who have studied the mechanical behavior of anterior cruciate-ligament grafts have attributed the increase in anterior translation of the tibia relative to the femur (an increase in the anterior laxity of the knee joint) to the temporal changes in the material behavior (strength and elastic properties) of the graft that occur throughout the process of remodeling. However, with the onset of motion of the joint, it is unclear whether the repeatable mechanical behavior of the graft remains unchanged immediately after fixation, if the fixation slips, or if the length of the graft changes and produces an increase in anterior translation of the tibia relative to the femur. It is also unknown if procedures performed by different surgeons, using similar graft material and similar operative techniques, can produce similar mechanical behavior of the graft, or if the behavior of the graft is similar to that of the normal anterior cruciate ligament. In an effort to address these questions, two surgeons performed a reconstruction of the anterior cruciate ligament on ten patients each (groups 1 and 2) with use of a bone-patellar ligament-bone graft. Immediately after fixation of the graft, a Hall-effect transducer was implanted to measure the changes in the length of the mid-substance of the graft while the knee was moved through twenty cycles of passive flexion-extension. Unlike the length pattern of the normal anterior cruciate ligament, the length pattern of the graft changed during the initial cycles of passive motion of the knee. We defined this phenomenon as the cyclic response of the graft and characterized it by calculation of the changes in the length of the graft at fixed positions of the knee across the multiple cycles of passive motion. In some patients, the length of the graft increased through the initial passive-motion cycles, while in others, it decreased. With the knee nearly extended, the predicted increase in anterior translation of the tibia relative to the femur, resulting from the increase in the length of the graft, was a maximum of 1.0 millimeter. This indicates that increases in anterior translation of the tibia relative to the femur can occur immediately after reconstruction of the anterior cruciate ligament and that changes in the length of the graft occur after fixation at loads that are less than the ultimate failure load of the graft or of the fixation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗