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Biomedical subjects

R Seil

Publications and source records attributed to R Seil.

At least 19 recordsLinked to original sources
PubMed2003

[Biodegradable meniscus fixations: a comparative biomechanical study].

PURPOSE: Numerous new all inside meniscus repair techniques using biodegradable fixation devices have become available in the last years. Few studies have dealt with the biomechanical properties of these implants so far. The aim of this study was to analyze meniscus repairs under cyclic loading conditions for different fixation devices (Meniscus Arrow, Clearfix Meniscal Screw, Meniscal Dart, BioStinger) and to compare them to standard suture techniques. MATERIAL AND METHODS: Eighty meniscus repairs on 27 medial porcine menisci were performed. For biomechanical testing loosening, number of failures, failure modes and failure loads were evaluated under cyclic and maximum loading conditions. Testing was performed on a materials testing machine. RESULTS: During cyclic loading 10 out of 40 (25%) fixation devices failed. A gap appeared between the 2 parts of the meniscus within the first loading cycles. The failure strengths obtained with the 4 meniscus fixation devices did not differ significantly (Meniscus Arrow: 44 N; Clearfix Meniscal Screw: 35 N; Meniscal Dart: 33 N; BioStinger: 54 N). Besides for the BioStinger, the values of the sutures were significantly higher. The use of a stronger suture material (PDS 0) increased the failure load significantly. During maximum loading the fixation devices failed by both pull-out of the head or the tip of the device, except for the BioStinger showing only pull-out of the head. All sutures failed by breakage, except for the PDS 0 horizontal sutures in which 50% of complete tissue failures could be noted. CONCLUSION: This study shows that meniscal fixation devices may fail under repetitive loading conditions. A gap appeared between the meniscal margins within the first loading cycles irrespective of the suture type and fixation device used. Both gapping and failure modes of the fixation devices may be design-specific. The maximum failure loads differed significantly between the bioabsorbable devices and the sutures. Stronger suture materials increased the failure loads significantly. To allow a complete evaluation of new meniscus fixation devices not only biomechanical, but also biological and clinical parameters need to be analyzed in forthcoming studies.

Absorbable Implants↗
PubMed2002

[Accuracy of fluoroscopic navigation of pedicle screws. CT-based evaluation of bone screw placement].

While the advantages of C-arm navigation in computer-assisted spine surgery are obvious, the accuracy of pedicle screw placement with virtual fluoroscopy still needs to be verified. The C-arm-based ION system (Medtronic Sofamor Danek) was used to navigate pedicle screw insertion in patients undergoing spinal surgery for various conditions. In a prospective study, a total of 160 screws were inserted in the first 30 consecutive patients since introduction of the system at our institution: 54 at the thoracic spine (highest level: TH4) and 106 at the lumbar spine. Computed tomography (CT) scans were performed postoperatively by two independent radiologists to control the accuracy of screw placement at the level of the pedicles after reconstruction of axial images according to Laine et al. The comparison of the calculated accuracy rate of pedicle screw placement using virtual fluoroscopy with reported results achieved with CT-based navigation shows similar results for virtual fluoroscopy and a remarkable increase of accuracy in comparison to reports on conventional pedicle screw placement.

Bone Screws↗
PubMed2002

[Replacement of the anterior cruciate ligament with a patellar tendon transplant].

The bone-patellar tendon-bone graft (BTPB) was the most commonly used graft for many years. The scientific database is more complete than for every other graft option. This review article presents the surgical techniques of ACL reconstruction with the BPTB graft, aspects of rehabilitation, clinical results, and postoperative problems with special emphasis on donor site morbidity.

Anterior Cruciate Ligament↗
PubMed2001

[Meniscus reconstruction. Established and innovative methods].

After the first description of meniscus repairs in the literature it took nearly a century until they were routinely performed in orthopaedic surgery. The scientific basis for meniscus reconstruction needed to be elaborated, including the study of the anatomy, and for instance the vascularisation and the function of the meniscus. After the first experiences with open repair, several arthroscopic techniques have been developed. It has been shown that several factors could influence the healing rate of meniscus lesions. One of the major factors is knee stability. Meniscus repairs performed in conjunction with reconstruction of the anterior cruciate ligament (ACL) have shown higher healing rates (generally > 75%) than isolated repairs, either in stable (50-75% healing rate) or in unstable knees (< 50% in some studies). The localization of the tear is probably the most important factor influencing the healing rate of meniscus repairs. Peripheral tears which are located in the vascular zone of the meniscus heal better than centrally located tears in the avascular area. Many efforts have been provided to enhance the vascularity in this part of the meniscus. None of the proposed techniques have been proven to be definitively effective, or they are too demanding for routine use. Conventional meniscus suture techniques are time-consuming, technically demanding and necessitate incisions at risk for neurovascular structures. In order to simplify meniscus repair several new implants have been developed. They have different forms and are made of different materials among which some are biodegradable. The first clinical results with these techniques are encouraging. However, some new complications have been described. Their incidence and the fate of intraarticular biodegradable devices still has to be defined, especially in the long-term. The present study describes the actual knowledge of meniscus repair and presents the new techniques. It also shows that several questions concerning meniscus repair still need to be answered, and points out the need for further controlled studies.

Anterior Cruciate Ligament↗
PubMed2001

[Effect of various suture strength factors on behavior of meniscus sutures in cyclic loading conditions].

The aim of this study was to analyze meniscal sutures under cyclic loading conditions for different suture types (vertical and horizontal mattress sutures) and suture materials (absorbable monofilament sutures: PDS 2-0; PDS-0, and PDS-1 USP). Testing was performed on medial porcine menisci, using a well-established biomechanical testing model with a complete longitudinal tear 3 mm from the periphery of the meniscus. Sixty specimens were used. One suture was tested at a time. During cyclic testing 100 load cycles were applied with a crosshead speed of 50 mm/min. Three different maximum loads (10 N, 20 N, and 40 N) were used. The preload was set at 5 N. After cyclic loading, the specimens were loaded until failure. During cyclic loading, a gap appeared between the two parts of the meniscus, and partial tissue failures were observed at the surface of the meniscus. Gapping was more marked with higher loads and with the weaker suture material (p < 0.001). Using PDS 0 and PDS 1 sutures, less partial tissue failures were observed compared to PDS 2-0 (p < 0.001). The ultimate failure loads after cyclic loading were higher with PDS-0 and PDS-1 sutures. With these suture materials vertical sutures were stronger than horizontal sutures (p < 0.05). Using PDS 2-0 this difference could not be found. These results show that the primary strength of meniscal sutures depends on the suture material. The frequency and the amount of gapping and partial tissue failures, which can be observed under cyclic loading, are less distinct with PDS-0 and PDS-1 compared to PDS 2-0. From a biomechanical point of view, PDS 0 and PDS 1 sutures are recommended for meniscal sutures to guarantee a high primary stability, a small amount of gapping, and few partial tissue failures.

Animals↗
PubMed2001

[Intermediate-term results after arthroscopic subacromial decompression with special reference to ongoing disability claims].

The objective was to evaluate mid-term results after arthroscopic subacromial decompression (ASD) with special focus on the bias due to an application to social insurance for pension based on sickness disability. The study group consisted of 42 patients (28 male, 14 female). ASD was performed in 1993 or 1994 for impingement stage II. The mean age was 49.5 years. Thirty-nine patients (93%) were evaluated by an independent observer for an average follow-up of 3.5 years (range 1.5-5). Patients satisfaction with the outcome was assessed by a visual analog scale graded from 0 (extremely dissatisfied) to 10 (extremely satisfied). The functional result was assessed using the Constant score. At follow-up the mean VAS value was 6.4 +/- 3.4. The Constant score improved from 49.6 +/- 18.5 to 84.8 +/- 14.3. The subgroup of patients having applied to social insurance for pension had significantly worse results compared with the remaining patients: VAS: 4.9 +/- 3.1 vs. 7.5 +/- 3.1; Constant-Score: 76.1 +/- 12.7 vs. 88.3 +/- 13.5. The fact that patients try to get benefit from social insurance based on sickness disability significantly biased the outcome after ASD.

Acromioclavicular Joint↗
PubMed2001

[Long-term results after excision of a popliteal cyst].

The objective was to evaluate long term results after removal of a popliteal cyst with special focus on recurrence rate and associated intraarticular pathology. Between 1982 and 1995 71 patients (23 women and 48 men between 21 and 75 years of age) underwent removal of a popliteal cyst. An additional arthroscopy of the knee joint was carried out in 51 consecutive patients starting in 1988. The mean follow up was 6.5 years (2 to 15 years), 66 patients (93%) were available. The subjective satisfaction with the outcome was assessed using a visual analogue scale (VAS) graded from 1 (highly satisfied) to 10 (highly dissatisfied). The popliteal region was evaluated by ultrasonography for recurrence of a cyst. During arthroscopy the predominant associated intraarticular pathologic finding was the lesion of the posterior horn of the medial meniscus (75%) and the lesion of the hyaline cartilage (90%). The cyst recurrence rate was 71%. In this subgroup grade III and grade IV chondral lesions were significantly more frequent (p < 0.001). Patients with a recurrence of the popliteal cyst rated the result significantly worse (7.6 +/- 2.3 vs. 3.4 +/- 2.3; p < 0.001). The recurrence rate was relatively high in the long term follow up. It depends strongly on the type of associated intraarticular pathology. Especially grade III and grade IV chondral lesions correlated significantly with recurrence of a popliteal cyst after removal. Therefore, the main goal of surgery should be the successful treatment of associated intraarticular pathologies.

Adult↗
PubMed2001

[Approach to open treatment of osteochondral lesions of the talus].

Arthroscopic techniques still represent the treatment of choice in osteochondral lesions of the talus (OLT). Open techniques may be used as an alternative or may be complementary to arthroscopic treatments. They are especially indicated in cases of large osteochondral lesions, difficult localisations and in cases of recurrent interventions. In addition to the type of treatment for the lesion itself, the choice of an ideal surgical approach is of paramount importance. Indications, operative technique, possible complications and rehabilitation are described in detail for each approach. Anterolateral, anteromedial, posterolateral and posteromedial soft-tissue approaches as well as medial and lateral malleolar osteotomies are discussed. If a distraction is not desired with arthroscopy, posteromedial and posterolateral soft-tissue approaches offer a good alternative for the treatment of posterior OLT. Osteotomy of the (medial) malleolus offers good visualisation of the medial talar dome. With the introduction of new techniques of osteochondral transplantations, the use of this approach is becoming more popular. However, it is an invasive technique and the risk of secondary osteoarthritis after malleolar osteotomy still needs to be determined.

Ankle Injuries↗
PubMed2001

Knee laxity after ACL reconstruction with a BPTB graft.

UNLABELLED: The objective of the study was to compare prospectively short-term and mid-term results after ACL reconstruction with special focus on changes in instrumented knee laxity. METHODS: The original study group included prospectively 58 patients who underwent arthroscopically assisted ACL reconstruction with BPTB graft in a two-tunnel technique between 1991 and 1993. Seven patients were lost to follow-up, leaving 51 patients for a first follow-up at 6 months and a second follow-up at 3-6 years (mean 4.3 years). Clinical results were evaluated by means of the Lysholm score and the IKDC score. Laxity was assessed using a KT-1000 arthrometer applying an 89 N anterior load in 20 degrees of flexion. Increased laxity was defined as a 3 mm increase in AP translation between the first and the second follow-up. RESULTS: At mid-term follow-up pivot shift was negative in 86% of cases. IKDC score: normal = 28%, nearly normal = 44%, abnormal = 24%, severely abnormal = 4%. KT-1000: < 3 mm = 68%, 3-5 mm = 24%, > 5 mm = 8%. The mean KT-1000 side-to-side difference was 1.08 (0.17) mm at 6 months and 2.01 (0.29) mm at 3-6 years. The difference was statistically significant (P < 0.005). According to the defined criteria, seven patients had increased laxity at the second follow-up, suggesting a malfunction of the graft due to stretch-out or injury. In this subgroup the mean KT-1000 measurements were 0.86 (0.26) mm at the first follow-up and 5.93 (0.54) mm at the second follow-up. In five of these patients, a malposition of the tunnels was identified as a possible cause. In the remaining group, KT-1000 measurements did not differ significantly between the first and the second follow-up [1.12 (0.20) mm versus 1.37 (0.21) mm]. CONCLUSIONS: Increase in AP laxity occurred in 14% of our cases between the first and the second follow-up. In most of these cases increased laxity was due to inadequate surgical technique, especially malposition of bony tunnels. If tunnel position was correct, there was no evidence for elongation of grafts over time as a general principle.

Adult↗
PubMed2001

Blood loss in anterior cruciate ligament (ACL) reconstruction with and without intercondylar notchplasty: does it affect the clinical outcome?

Blood loss is associated with any surgical procedure and should be reduced wherever possible. It was our impression that notchplasty adds to the amount of postoperative bleeding after anterior cruciate ligament (ACL) reconstruction. With posterior placement of the tibial tunnel, notchplasty is optional in many cases. This study aimed to quantify blood loss with and without notchplasty after arthroscopically assisted ACL reconstruction using bone-patellar tendon-bone autografts. We performed a prospective clinical study of 58 patients, who had undergone arthroscopically assisted autogenous patellar tendon ACL reconstruction. In group I, a notchplasty was necessary according to the local anatomical criteria (intraoperative impingement test). In group II, ACL replacement could be performed without notchplasty. Single and total day drainage volume, serum and suction drain hemoglobin (Hb) and hematocrit (Hct) levels were monitored. One year after surgery, the patients were reviewed to assess the outcome according to the IKDC and Lysholm scores and the KT-1000 arthrometer. The total drainage volume was 448 ml (range 150-550 ml) in group I and 299 ml (range 50-420 ml) in group II (p < 0.001). The serum hematocrit (Hct) decrease was 9.7% in group I and 7.4% in group II (p < 0.001). At 12 months after surgery, the IKDC and Lysholm score evaluations and the KT-1000 arthrometer measurements revealed no clinical differences between the notchplasty and non-notchplasty groups. Despite a 30% increase in blood loss, notchplasty has been shown to be a useful procedure to prevent graft impingement without negative side-effects.

Adult↗
PubMed2001

The fate of the poly-L-lactic acid interference screw after anterior cruciate ligament reconstruction.

We report the persistence of a poly-L-lactic acid (PLLA) interference screw 2.5 years after anterior cruciate ligament (ACL) reconstruction with Achilles tendon allograft. The arthroscopy was performed because the patient sustained a reinjury of the ACL graft, making ACL revision surgery necessary. At the time of arthroscopy, both PLLA screws were macroscopically still intact but could not be removed in 1 piece. No inflammation could be observed either macroscopically or in the histologic analysis. The biopsy specimen from the femoral insertion of the graft showed parts of the PLLA material surrounded by scar tissue. This case shows that biodegradation of PLLA material in the knee joint causes no irritation and can take several years, even if the material is in contact with the synovial fluid.

Absorbable Implants↗
PubMed2001

Transient bilateral osteoporosis of the hip in pregnancy. A case report and review of the literature.

Osteoporosis of the hip is a rare complication of pregnancy, the diagnosis of which can only be determined by radiologic means. Differentiation between osteonecrosis and osteoporosis remains problematic in some cases. Magnetic resonance imaging was reported as useful for the diagnosis of osteoporosis. Treatment of osteoporosis of the hip in pregnancy should be conservative including physical therapy, restricted weight bearing and analgetic therapy. We report an unusual case of bilateral transient osteoporosis of the hip in pregnancy.

Adult↗
PubMed2001

Fracture of the proximal tibia six months after Fulkerson osteotomy. A report of two cases.

The Fulkerson osteotomy has proved to be a reliable treatment for subluxation of the patella due to malalignment. Aggressive rehabilitation in the early postoperative period is unwise since the proximal tibia is weakened by the oblique osteotomy. Early weight-bearing and unrestricted activity have caused fractures in a few patients. Even late in the postoperative period the osteotomy may adversely influence the biomechanical properties of the proximal tibia. We describe two athletes who sustained a fracture of the proximal tibia, during recreational activities, six months after a Fulkerson osteotomy. Both had been bearing full weight for about ten weeks without complaint. Bony healing of the osteotomy had been demonstrated on plain radiographs at ten and at 12 weeks. After a Fulkerson osteotomy, jogging and activities which impose considerable impact force should be discouraged for at least nine to 12 months.

Adult↗
PubMed2000

[Donor site problems after anterior cruciate ligament reconstruction with the middle third of the patellar ligament].

In a retrospective study we examined the clinical and sonographic changes after anterior cruciate ligament reconstruction with lig. patellae. 51 patients were evaluated clinically and sonographically after arthroscopically assisted ACL-reconstruction with a bone-patella tendon 3-6 years (mean 4.3 years) postoperatively. Certainly 18 patients (35%) reported about an anterior knee pain, but only 2 patients (4%) complained about pain during activities of daily living and 3 patients (6%) about pain during slight sports activities. Retropatellar crepitations was found in 24 patients (47%) on the operated side and at 11 patients (22%) on the non operated side. Twenty nine patients (57%) complained about a discomfort or pain when kneeling on the operated side. In 13 patients (26%) sonography showed a shortening of the patella ligament by 4 mm or more. Only few patients are strongly limited in their activity by the anterior knee pain. Neither our results nor the literature give evidence, that the tendon defect is the underlying cause of this pain syndrome. However, the number of patients with pain during kneeling on the operated side was relatively high. The semitendinosus gracilis graft should be considered for patients who have to knee during working or recreational activities.

Anterior Cruciate Ligament↗
PubMed2000

Reliability and interobserver variability in radiological patellar height ratios.

This study evaluated the reliability and interobserver variability of five patellar height ratios as measured by two examiners on standard radiographs: Insall-Salvati (IS), modified Insall-Salvati (MIS), Blackburne-Peel (BP), Caton-Deschamps (CD), and Labelle-Laurin (LL). Plain lateral radiographs with a knee flexion angle of 20 degrees for IS, MIS, BP, and CD ratios and 90 degrees for the LL method of 22 knees of 21 patients with varying pathological knee conditions were analyzed. Statistical results revealed a low interobserver variability with high correlation coefficients (0.86 for IS, 0.82 for MIS, 0.86 for BP, 0.92 for CD, and 0.81 for LL; P > 0.3) and low mean interobserver errors. However, regarding the reliability of the radiographic results of the different methods for patella alta, baja, or norma we found varying results in 68% of the patients. In two patients the patellar height was classified as alta, norma, or baja depending on the ratio used. Regarding the definitions of patellar height used by the authors of these methods, we found the lowest number of normal patellae with the IS ratio and no patella alta for the CD ratio. The LL method revealed the highest number of patella alta. The BP ratio showed intermediate results for both patella alta and baja, being the most moderate method. This study showed that there was a good interobserver reliability for the evaluation of patellar height according to the common radiological ratios. However, the high frequency of differing results between the different radiographic ratios showed that patellar height classification as "alta," "norma," or "baja" depends heavily on the chosen index. The differing results were due mainly to the normative patellar height data and to anatomical differences. Based on these findings we recommend a ratio using the articular surface of the patella in relation to the joint line. We recommend the BP method because it revealed the lowest interobserver variability and discriminated best among the groups alta, norma, and baja.

Adolescent↗