Effectiveness of safety vests in pediatric horseback riding.

BACKGROUND: Despite the benefit of safety vests to the reduction of torso injuries in children and adolescents is unclear, its' use is recommended. The aim of the present study is to determine the effectiveness of safety vests actually used in pediatric equestrian activities. PATIENTS AND METHOD: In this case-control-study, we analyzed the accidents of 92 riders aged 18 or younger who fell off a horse onto his/her torso during a period of 18 months. Data were gathered from the clinical records. Additionally, a questionnaire was administered on the day of trauma by the patients and/or their parents. RESULTS: The cases comprised 31 patients who sustained torso injuries. The controls were 61 riders with injuries of other body parts than to the torso. Safety vest use was not associated with a lower risk of torso injuries (OR=1.18, 95% CI (0.50, 2.81), p=0.707). Post hoc power analysis revealed that within such a setting an odds ratio of 0.266 could be found with a power of 80%. CONCLUSION: This study is not able to show an association between wearing a torso protector and protection from torso injuries, probably due to confounding. We did not detect a high effect of safety vest usage in our study population. Whether the development of a new generation of safety vests might be more effective remains unclear. An effective vest should be adapted to the requirements of children and adolescents and should protect the thorax and abdomen, but also the cervical and the lumbar spine.

Follow-up costs up to 5 years after conventional treatments in patients with cartilage lesions of the knee.

In this retrospective cross-sectional study, we contacted patients who had been diagnosed with (and, if necessary, treated for) knee cartilage defects by arthroscopy at one of seven treatment centres in Germany between 1997 and 2001. In early 2003, patients completed a questionnaire on the health care resources they had used since the time of the arthroscopy. Based on this information, we determined follow-up costs. Data from a total of 1,708 patients were included in the final analysis. Of these, 1,070 were assigned to the initial operation (IO) group (61% men, 49+/-15 years; 39% women, 52+/-14 years) and 638 were assigned to the re-operation (RO) group (64% men, 44+/-13 years; 36% women, 47+/-14 years). The cumulative direct medical costs caused by knee complaints for the first 5 years following the arthroscopy were 1,984 Euro for the IO population and 4,203 Euro for the RO population. The cumulative indirect costs (i.e. costs associated with loss of productivity), however, amounted to 7,669 Euro and 15,265 Euro, respectively, and were thus almost four times as high as the cumulative direct costs. This is the first study that quantifies the considerable follow-up costs in patients who have undergone surgery for knee cartilage defects. As such, it may provide a yardstick for future treatments.

Evaluation of the learning curves associated with uncemented primary total hip arthroplasty depending on the experience of the surgeon.

The aim of the paper is to prove and to portray the learning curve in total hip arthroplasty. This prospective study included 168 patients who were operated on by three surgeons, all demonstrating different degrees of experience in performing total hip arthroplasty. Perioperative complications and postoperative radiographs were analysed. Patients were re-examined clinically and radiologically five years postoperatively. In addition, a second study with 41 patients was performed, evaluating especially the learning curve of the highly skilled surgeon in using a femoral neck prosthesis. Radiological complications presented by the first 84 operated patients (2 nd study: 25 hips) were significantly higher than those in the following 84 patients (2 nd study: 26 hips). The learning curve of all surgeons was completed after 20 operations regardless of their experience. Clinical results at follow-up were not influenced by the learning curve. Intensive preoperative planning and exchange of experiences will reduce the length of the learning curve within and outside every clinic.

[Obesity and low back pain--biology, biomechanics and epidemiology]. / Ubergewicht und Bandscheibenschaden. Biologie, Biomechanik und Epidemiologie.

Aim of the following paper is to describe the impact of obesity on low back pain. The mature disc is one of the most sparsely cellular tissues in the body, water content and concentration of proteoglycan decreases with increasing age. Both, static compressive loading and increased pressures, may result in damage of the integrity of the disc like tears of the anulus, followed by mechanical compression or chemical damage of the nerve roots. The intradiscal pressure is dependent on the body position and increases in the following order: prone, standing, upright sitting. In addition, bending and weight lifting increases the intradiscal pressure. For asymptomatic subjects, reported prevalences of disc degenerations in MRI studies are often quite high. Several studies report a significant association between body weight and low back pain, some do not. Recent research indicates that heredity has a dominant role in disc degeneration and low back pain, although the complex distributions and interactions of genetic factors are currently unknown.

[Biomechanical testing of different ventral fixation devices on the bovine lumbar spine]. / Biomechanische Testung verschiedener ventraler Plattensysteme an der bovinen Lendenwirbelsäule.

AIM: The primary stability of ventral fixation systems has been improved over the past years and special implants supporting minimally invasive procedures have been developed. The aim of this study was to analyze the primary stability of several of these implants. METHODS: Thirty (30) lumbar segments from 5 to 7-month-old calves were harvested and tested on a pure moment apparatus (PMA) as well as a modified materials testing machine (MTS) according to the European standard recommendations of Wilke et al. Three different implant systems (MACS, Centaur and Z-plate) were included. ROM, neutral zone and stiffness were tested on the PMA up to 10 Nm, stiffness at an eccentric axial load of up to 1500 N was tested on the MTS. Bone density was investigated for all specimens. Statistical analysis was performed by ANOVA and LSD tests. RESULTS: Primary stability was improved by all fixation devices compared to the physiological specimen. The MACS implant was more stable than the Centaur and Z-plate with the exception of in lateral bending [where the Z-plate was stiffer]. Bone density was comparable in the three different experimental groups. CONCLUSION: Minimal invasive ventral fixation devices are becoming popular. The primary stability of the minimal invasive MACS was comparable to those of other well-known ventral fixation devices of the lumbar spine.

[Corrective bone operations for treatment of deformities caused by obstetrical brachial plexus palsy]. / Knöcherne Korrektureingriffe zur Behandlung von Deformitäten nach geburtstraumatischer Arm-Plexus-Lähmung.

In an adult, a marked deformity of the upper arm and forearm with loss of function of the limb due to obstetrical brachial plexus palsy has been corrected. An external rotational osteotomy of the humerus and radioulnar arthrodesis resulted in an improved function.

[MRI in spondylitis and spondylodiscitis]. / MRT bei Spondylitis und Spondylodiszitis.

Magnetic resonance imaging (MRI) is highly sensitive and specific for the diagnosis of spondylitis and in that respect is superior to other radiologic methods. Its excellent morphological resolution allows early recognition of pathologies and spread of the spondylitis. Affected vertebral bodies and discs reveal typical alterations in T1- and T2-weighted images; post-gadolinium images are necessary to improve specificity. MRI helps to diagnose tumors and degenerative changes. Thus, MRI is the method of first choice in the diagnosis and surveillance of spondylitis and spondylodiscitis.

[Characteristics of the learning curve in total hip endoprosthesis exemplified by the BiContact prosthesis]. / Charakteristik der Lernkurve bei der Hüfttotalendoprothese am Beispiel der BiContact-Prothese.

AIM: Total hip arthroplasty is a common operation but there are few data describing the learning curve of this operation. The aim of the presented study is to prove and describe the learning curve in total hip arthroplasty. METHOD: Between 1991 and 1993, 168 patients were included in this prospective study, operated by three surgeons having different experiences in operating total hip arthroplasty. Perioperative complications and postoperative X-rays were analysed. Patients were re-examined clinically and radiologically and by a questionnaire 5 years after operation. RESULTS: Radiological complications of the first 84 operated patients were statistically significantly higher than those of the following 84 patients, except for minimal bone fractures and leg lengthening. The learning curve of all surgeons was finished after 20 operations independent of their experience. Clinical results were not influenced by the learning curve at follow-up. CONCLUSIONS: Regardless of the experience of the surgeon, the learning curve in total hip arthroplasty is finished after about 20 operations for each surgeon. Intensive preoperative planning and exchange of experience inside and outside every clinic will shorten the length of the learning curve.

[Possibilities and limits of conservative therapy of spondylitis and spondylodiscitis]. / Möglichkeiten und Grenzen der konservativen Therapie bei Spondylitis und Spondylodiszitis.

BACKGROUND AND AIM OF THE STUDY: For many years the treatment of spondylitis and spondylodiscitis has been discussed controversially. The aim of this study is to report on objective and subjective mid-term results of therapy of spondylitis and to present a differentiated concept of treatment. METHODS: Between 1988 and 1996, 58 patients were treated with spondylitis or spondylodiscitis. Nine of these patients had to be operated. A biopsy was taken in all of the cases. According to the antibiogram obtained by the biopsy, antibiotics were applied intravenously. The patients were immobilized by a plaster bed for at least 6 weeks and were then treated by a spinal orthosis for another 3 months. Patients were re-examined clinically and radiographically and by a questionnaire (including Roland-Morris score), after 8 years on average. RESULTS: Patients were diagnosed correctly 4 months after the begin of the disease. Spondylitis was predominantly localized in the lumbar spine. A positive bacteriological culture was derived from one third of the biopsies; none of them was a specific culture. C-reactive protein was revealed as appropriate for diagnosis and follow-up of spondylitis. In 84% of the patients a total or partial bony fusion was demonstrated radiographically. Questionnaire assessment revealed a significant decrease of the Roland-Morris score (17.8-7.4) and a significant relief of pain (8.9-2.5). CONCLUSIONS: We recommend surgical treatment on patients with major vertebral body destruction, epidural abscess and progressive neurological impairment. These indications for operation can be prevented by a rapid diagnosis, so that spondylitis can be successfully treated by consequent immobilization in a plaster bed and appropriate antibiotics.

Ultrasound examination of neonatal hip: correlation of twin pregnancy and congenital dysplasia.

Twin pregnancy is considered to be a risk factor for congenital dysplasia of the hip. From 1987 until 1996, the hips of 4476 (2260 male, 2216 female) newborn babies were examined by ultrasound according to Graf's technique and classification in our hospital. In this study, we compare the results of twins and singletons for this risk factor. Of the newborns, 97 (2.2%) were twins (40 male, 57 female); 39 pairs of twins (10 male/male, 19 female/female, 10 male/female) and 19 individual twins (6 male, 13 female) were investigated. Hips of type Ia, Ib and IIa (alpha > or = 55 degrees) are not pathologic; hips of type IIa (alpha <55 degrees ) need an early control examination; and hips of type IIc, D, IIIa, IIIb and IV require therapy. Types Ia, Ib, and IIa (alpha > or =55 degrees ) were found in 4207 (94.0%) of all newborns, in 4112 (93.9%) of the singletons, and in 95 (97.9%) of the twins. Early control examination and/or therapy (indicated for types IIa (alpha <55 degrees ), IIc, D, IIIa, IIIb, and IV) were necessary in 269 (6.0%) of all cases, in 267 (6.1%) of singletons and two (2.1%) of twins. Twins with additional factors such as breech position birth, hip dysplasia in the family or premature birth did not show the types of hip IIa (alpha <55 degrees ), IIc, D, IIIa, IIIb, IV. We did find these hips in two (3.5%) of the female twins, but not at all in the male twins. Statistically, twins with or without other risk factors that are known before birth did not show significantly more of type hip IIa (alpha <55 degrees ), IIc, D, IIIa, IIIb, IV (P>0.05).

Primary stability of different implants used in conjunction with high tibial osteotomy.

High tibial osteotomy in the varus knee has been successfully performed for a long time. Several newer operation techniques have been established in recent years. We tested the primary stability of several of these techniques in vitro. Ten human cadaveric fresh-frozen specimens were used that had a mean age of 54 years (range 29-72 years) and a weight of 55-85 kg. All specimens were harvested, frozen, and subsequently thawed under the same conditions before testing. The following implants were tested: one-third tubular plate with a cortical screw (AO, Synthes), blade plate with screws (Giebel's plate, Link), bone staples (osteotomy staples, Krackow staples, Smith & Nephew) and an external fixator (Orthofix). The specimens were mounted in metal cylinders and then loaded in two different setups: transverse forces were applied to the osteotomy site by hanging weights parallel to the osteotomy plane in a static-loading frame, and axial forces were applied by a materials testing machine (Zwick). Displacement was recorded using a linear variable displacement transducer (LVDT). The highest stability was achieved by the external fixator and the bone staples. Giebel's blade plate and the one-third tubular plate were less stable. Retention of an intact medial cortex was a decisive factor in obtaining primary stability. We found that the primary stability of the tested devices was generally comparable as long as they were correctly implanted. It was also noted that lateral spacing of the osteotomized bone should not exceed 3 mm. If the medial cortex is transected intraoperatively in lateral osteosynthesis, an additional medial implant is necessary to ensure sufficient primary stability. For practical reasons it was necessary to neglect the contribution of the soft tissues around the knee, although all implants were tested under the same conditions. Care should thus be taken when interpreting the results of this study in a clinical setting.

[High tibial osteotomy--primary stability of several implants]. / Zur Berechtigung von verschiedenen Osteosyntheseformen bei der Tibiakopfumstellungsosteotomie.

INTRODUCTION: High tibial osteotomy in varus knee has been performed for a long time. Several newer operation techniques have been established in recent years. We tested the primary stability of several of these techniques in vitro. MATERIAL AND METHODS: 10 human cadaveric fresh-frozen specimens were tested with a mean age of 61 years (range 50-72 years), and weight of 65 to 78 kg. The following implants were tested: One-third-tubular plate with cortical screw (AO, Synthes), blade plate with screws (Giebel's plate, Link), bone staples (osteotomy staples, Krackow staples, Smith & Nephew), external fixateur (Orthofix). The specimens were fixed in metal cylinders and then loaded in two different apparati: Shear forces were applied to the osteotomy site by hanging weights parallel to the osteotomy plane in a static-loading frame, and axial forces were applied by a materials testing machine (Zwick). Load displacement was recorded by inductive displacement transducers. RESULTS: The highest stability was achieved by the external fixateurs and the bone staples. Giebel's plate and the one third tubular plate were less stable. Receipt of the medial corticalis was decisive for primary stability of the implants. CONCLUSION: The clinical significance of the results is limited by the relevance of the protocol, which for practical reasons did not account for the soft tissue situation around the knee. Thus, primary stability of the tested devices was generally comparable as long as they were correctly implanted. It was found, that lateral distance of the osteotomized bone should not exceed 3 mm. If the medial cortical is sawed, another medial implant is necessary to ensure sufficient primary stability.

Follow-up results 17 years after resection arthroplasty of the great toe.

Resection arthroplasty of the first metatarsophalangeal joint is a well-known operation. The follow-up results more than 17 years after arthroplasty for hallux valgus are reported and discussed. Between 1971 and 1980, 335 resection arthroplasties were performed on 205 patients. The sole indication for resection arthroplasty of the great toe in this study was hallux valgus. The technique involved removal of the proximal one-third of the phalanx with interposition of a capsular flap, occasionally including temporary Kirschner wire fixation. After 17.6 years on average, 102 patients were re-examined clinically and radiographically. Questionnaire assessment revealed a significantly prolonged walking distance, and 70% of the patients were pain-free at follow-up investigation, whereas 67% suffered from severe pain before the operation. Clinical evaluation showed diminished weight-bearing of the great toe during walking and a reduced range of motion of the resected first metatarsophalangeal joint. Radiographic shortening of the proximal phalanx was 37%. The average hallux valgus angle was 23 degrees at follow-up and 34 degrees prior to surgery. The unacceptably high rate of hallux valgus relapse, especially due to a high intermetatarsal angle, emphasizes the unsatisfactory long-term results of the resection arthroplasty. We now recommend this operation for older patients only, and a differentiated approach using reconstructive procedures according to the clinical and radiographical situation for younger patients.

[Long-term outcome of arthroplasty of the first metatarsophalangeal joint]. / Langzeitergebnisse nach Arthroplastik im Grosszehengrundgelenk.

INTRODUCTION: Resection arthroplasty of the first metatarsal-phalangeal joint is a wellknown operation for hallux valgus. The follow-up results more than 17 years after arthroplasty are recorded and discussed. MATERIAL AND METHOD: Between 1971 and 1980, 335 arthroplasties were performed on 205 patients. The only indication for arthroplasty of the great toe was hallux valgus. The technique of arthroplasty was according to Keller-Brandes. 102 patients were reexamined clinically and radiographically, after 17.6 years on average. RESULTS: Questionnaire assessment revealed a significantly prolonged walking distance and 70% of the patients were painfree at the time of investigation, whereas 67% suffered from severe pain before operation. Clinical evaluation showed diminished weightbearing of the great toe during walking and a reduced range of motion of the partial-resected first metatarsal-phalangeal joint. Radiographically the shortening of the phalangeal bone of 37% was evident as expected. Hallux-valgus-angle was 23 degrees at the time of investigation and 34 degrees preoperatively in the mean. DISCUSSION: The high rate of hallux valgus relapse, especially due to a high intermetatarsal angle demonstrate unsatisfactory longterm results by the Keller-Brandes operation. We now recommend this operation for older patients and a differentiated approach according to the clinical and radiographical situation for younger patients.

[10 years follow-up of athrodeses of the hindfoot joints and upper ankle joint]. / 10-Jahres-Verläufe nach Arthrodesen der Rückfussgelenke und des oberen Sprunggelenks.

PURPOSE: What is the clinical and radiographic outcome of arthrodeses at the hindfoot and at the ankle more than 10 years postoperatively? METHODS: Between 1968 and 1988, 155 arthrodeses (ankle joint, triple arthrodeses, subtalar, pantalar and talonavicular arthrodeses) were performed on 147 patients. Indications for arthrodesis were posttraumatic arthritis, congenital deformity, idiopathic degenerative arthritis and rheumatoid arthritis. A variety of internal fixation devices or no internal fixation were used. 79 patients with 82 arthrodeses were reexamined clinically and radiographically, after 11.1 years on average. Static and dynamic foot print measurements were recorded with a capacitive sensor system. Another 26 patients with 27 arthrodeses replied to a questionnaire. RESULTS: Subjectively, the average pain score improved significantly. The overall function score improved only slightly. Results were inferior in the talonavicular arthrodesis. Radiographic evaluation revealed bony union in only 59 percent of the arthrodeses, one third at the talonavicular joint. Secondary degenerative arthritis of the foot and ankle occurred in 107 joints of the 82 feet. Evaluation of dynamic foot pressure measurements revealed an overall prolonged weightbearing on the midfoot region. CONCLUSION: An unacceptably low rate of bony union in some locations, a high incidence of secondary degenerative changes at neighboring joints, and a persistent abnormality of the plantar weightbearing pattern in the operated feet demonstrate unsatisfactory results with the techniques used more than 10 years ago. We now recommend stable internal fixation with optimum adaptation of the bone surfaces of the arthrodesis.

[Hindfoot arthrodesis]. / Rückfussarthrodesen.

Arthrodesis of the hindfoot is indicated in congenital foot deformity of young adults, in posttraumatic arthrosis of the subtalar joint following calcaneus fractures, in idiopathic, isolated arthroses of hindfoot joints, in rheumatoid arthritis and in deformities of the longitudinal arch of the foot. Common and useful combinations are the triple-arthrodesis and the arthrodesis of the subtalar and the calcaneocuboid joint, in particular if both joints are affected by calcaneus fractures. Arthrodesis of the subtalar and the talonavicular joint are often performed as isolated procedures. The three-dimensional structure of the hindfoot articulations may impede perfect contact of the bone surfaces in combined arthrodeses. Various fixation methods are in use. Follow-up examination of 52 arthrodeses after 11.1 years revealed good, symptomatic improvement in most patients. However, complete bony union was achieved in only 47 percent, and this was due to insufficient stabilization of the arthrodesis in many cases. In view of comparable rates of pseudarthroses in the literature, we advocate stable internal fixation with screws or bone staples.