[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.

[Diagnosis of rupture of the anterior cruciate ligament]

Clinical examination has remained the key for diagnosis of meniscal and ligament lesions of the knee. Economical use of imaging techniques is based on adequate clinical examination. Standard radiographic examination is still a simple and valuable method. Magnetic resonance tomography has made great progress during the past few decades. For this reason, this article centers on this imaging modality.

Prevalence of spontaneous osteonecrosis of the medial femoral condyle in elderly patients

Aseptic osteonecrosis of the medial femoral condyle has recently been reported as a complication of arthroscopic surgery. The time interval between the onset of symptoms and pathognomonic MRI changes (diagnostic window) is not known for osteonecrosis of the knee. To determine the prevalence of early-stage spontaneous osteonecrosis of the knee (SONK) we prospectively examined 176 patients by MRI between May 1998 and December 1999. In six patients MRI revealed a bone marrow edema pattern and subtle subchondral bone changes in the medial condyle consistent with early-stage SONK (prevalence of 3.4%); in the 53 patients older than 65 years the prevalence was 9.4%. In 10 patients (5.7%) the bone and marrow changes on MRI imaging either resolved on follow-up MRI and were regarded as transient epiphyseal lesions or were considered to be reactive changes due to underlying degenerative articular disease. Including MRI in the preoperative diagnostic procedures could avoid missing the diagnosis of avascular necrosis before planning an operative treatment of suspected meniscal tears in elderly patients.

Extracorporeal shockwave therapy (ESWT) in patients with chronic proximal plantar fasciitis

The aim of this study was to compare the effect of extracorporeal shockwave therapy (ESWT) in patients with chronically painful proximal plantar fasciitis with a conventional conservative treatment consisting of nonsteroidal anti-inflammatory drugs, heel cup, orthoses and/or shoe modifications, local steroid injections and electrotherapy. Forty-seven patients (49 feet) with a previously unsuccessful conservative treatment of at least six months were randomized to two groups. Treatment of Group 1 (25 heels) started immediately with three sessions of ESWT (3000 shockwaves/session of 0.2 mJ/mm2) at weekly intervals. In the patients of Group 2 (24 heels) treatment was continued for 12 weeks. After this period they were treated using the protocol of Group 1. No significant difference of pain and walking time after further non-ESWT treatment (three months) was seen. Six months after ESWT pain decreased by 64% to 88% on the visual analog scale (VAS) and the comfortable walking time had increased significantly in both groups.

Fatigue testing of suture anchors

In a porcine tibia model, we subjected widely used anchor-suture combinations to a fatigue-testing protocol. The Ethibond No. 2 suture was the weakest part of the anchor-suture combinations when they were loaded to failure by a single pull. Under cyclic-loading conditions, fixation strength was decreased compared with single-pull tests. The suture/anchor interface was identified as the weakest link in the Mitek GII/No. 2 combination and in the Zimmer Statak 3.5/No. 2 combination. In most cases the suture was worn through at the eyelet. Threading the GII anchor with a No. 5 suture and use of larger anchors in combination with No. 2 sutures increased the fatigue strength. Suture breakage at the knot was the predominant failure mode for biodegradable anchors inserted into cortical bone. The highest fatigue strength was seen for the Super Anchor/No. 5 combination when the anchor was inserted in cortical bone. Fatigue testing is crucial for evaluation of suture anchors and should be performed along with single-pull testing. The mechanical performance of a suture anchor threaded with a defined suture depends on several key factors: the pullout strength of the anchor, the tensile strength of the suture, and the interaction of anchor and suture at the eyelet (suture/anchor interface).

In vitro reconstructed human epithelia reveal contributions of Candida albicans EFG1 and CPH1 to adhesion and invasion

The individual and synergistic contributions of two transcription factors, EFG1 and CPH1, have been characterized with regard to adhesion to, and invasion of, human epithelia by Candida albicans. For this purpose two in vitro reconstructed tissue models were developed. A multi-layered model of human epidermis was used to simulate superficial infections of the skin, whereas a reconstructed human intestinal model was used to mimic the first steps of systemic infections. It was shown that C. albicans deleted for both transcription factors CPH1 and EFG1, in contrast to the congenic clinical isolate Sc5314, was neither able to adhere to, nor to penetrate, either of the model systems. A strain deleted for EFG1 alone showed significant reduction in adhesion and was not able to penetrate through the stratum corneum. However, strains deleted for CPH1 showed phenotypes paralleling the phenotypes of the clinical isolate Sc5314. Using different types of multi-layered human tissues reconstructed in vitro the individual contributions of Efg1p and Cph1p to two important virulence factors of C. albicans, namely adhesion and invasion, could be defined.

Popliteal cysts in adults. Prevalence, associated intraarticular lesions, and results after arthroscopic treatment

The objective of this prospective study was to determine the prevalence of popliteal cysts and the associated intraarticular lesions in a group of 100 patients scheduled for arthroscopic surgery of the knee and to evaluate the results of arthroscopic treatment for these intraarticular lesions without removal of the cyst. One hundred patients without any knee complaints served as a control group. The diagnosis of a popliteal cyst was made on the basis of ultrasonography. The prevalence of popliteal cysts was 20% in the study group and 0% in the control group. Patients with a popliteal cyst had a significantly higher prevalence of medial meniscal tears (70% versus 19%) and of chondral lesions (85% versus 28%). Tears of the lateral meniscus, however, were more evenly distributed (20% versus 36%). Sixteen of 20 patients with a popliteal cyst were available for a follow-up examination 1 to 3 years after the arthroscopic procedure. Eleven popliteal cysts had persisted. Chondral lesions were the most relevant prognostic factor; all patients with persisting cysts had grade III or grade IV lesions. We conclude that the popliteal cyst is a secondary phenomenon and that treatment should address the underlying intraarticular lesions. In cases of osteoarthritis it may be impossible to treat the chondral lesion successfully in terms of eliminating the effusion.

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.

[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.

Knee laxity after ACL reconstruction with a BPTB graft

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.

[Biomechanical properties of interference screw implantation in replacement of the anterior cruciate ligament with patellar and hamstring transplants. An experimental study using roentgen stereometry analysis (RSA)]

This experimental roentgen stereometric analysis (RSA) study was performed to measure micromotions between the graft and tunnel under submaximal load in anterior cruciate ligament (ACL) reconstruction. The aim was to evaluate the maximum load at failure, linear stiffness, and slippage of bone-patellar-tendon-bone (BPTB) grafts fixed with interference screws compared to quadrupled hamstring grafts fixed with interference screws. We used 15 porcine tibia specimens for the study. In the BPTB group, the 10 x 25-mm bone plugs were fixed in a tunnel with 10 mm in diameter using a 7 x 25-mm titanium interference screw (n = 5) or a biodegradable screw (n = 5). The five hamstring transplants were folded to a four-stranded graft and armed with a baseball stitch suture. The sutured side was fixed with a 7 x 25-mm biodegradable polylactide screw in an 8-mm tunnel. The tibial bones, tendon grafts, and interference screws were marked with tantalum beads. The grafts were mounted to a custom made load frame and loaded parallel to the axis under RSA control increasing the force in steps of 50 N. Micromotions between bone plug, screw, and tibia were measured with RSA. Accuracy of RSA for the in vitro study was evaluated as 0.05 mm. Hamstring grafts failed at significantly lower maximum loads (492 +/- 30 N) than BPTB grafts (658 +/- 98 N). Linear stiffness of the hamstring graft fixations was eight times lower compared to the BPTB grafts (403 +/- 141 N/mm vs 3500 +/- 1300 N/mm). There was no significant difference between the biodegradable and titanium screws in the BPTB group. Slippage of the graft started at 82 +/- 35 N load in the hamstring group and at 428 +/- 135 N in the BPTB group. Slippage of the graft at 75% of the maximum pull-out strength was measured as 0.36 +/- 0.25 mm in the BPTB and 2.58 +/- 1.08 mm in the hamstring group. The interference screw fixation of a quadrupled hamstring graft showed a lower linear stiffness and an earlier slippage compared to a patellar tendon bone plug. Slippage of the hamstring grafts at submaximal loads may result in fixation failure during rehabilitation.

[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.

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.

[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.

[Tendinosis calcarea of the rotator cuff]

Calcifying tendinitis of the rotator cuff is a common disorder of the shoulder which affects mainly individuals between 30 and 50 years of age. The etiology is still a matter of speculation. The calcification is a reactive process actively mediated by cells in a viable environment. The deposit undergoes an evolution (precalcific stage--calcific stage with formative phase, resting period and resorption--postcalcific stage), which ultimately remodels normal tendon tissue. However, the evolutionary stages of the disease do not always follow the typical sequence. A symptomatic deposit may persist or postcalcific tendinitis develop. The treatment should be based on the knowledge of the natural history of the disease, which shows a strong tendency towards self-healing by spontaneous resorption of the deposit. The stage of evolution of the disease should be judged, combining pain history, morphology of the deposit on plain X-rays, and ultrasound findings. The therapeutic approach depends on the evolution of the disease. During the resorption phase we favor a conservative approach. For deposits which are not under resorption we propose a concept which consists of three steps: a conservative approach, extracorporal shock wave therapy (ESWT) or needling, and arthroscopic surgery. The efficacy of ESWT and needling has still to be proven. Patients with persisting pain after steps 1 and 2 are candidates for surgical removal of the deposit. We prefer the arthroscopic approach. In some cases an additional arthroscopic subacromial decompression (ASD) is indicated.

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.

[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.

The TEA/ATTS transcription factor CaTec1p regulates hyphal development and virulence in Candida albicans

The temporal and spatial expression of stage-specific genes during morphological development of fungi and higher eukaryotes is controlled by transcription factors. In this study, we report the cloning and functional analysis of the Candida albicans TEC1 (CaTEC1) gene, a new member of the TEA/ATTS family of transcription factors that regulates C. albicans virulence. The promoters of the type 4, 5 and 6 proteinase isogenes (SAP4-6) contain repetitive TEA/ATTS consensus sequence motifs. This finding suggests a possible role for a homologue of Saccharomyces cerevisiae TEC1 during the activation of proteinase gene expression in C. albicans. CaTEC1 is predominantly expressed in the hyphal form of C. albicans. In vitro, serum-induced hyphal formation as well as evasion from MPhi after phagocytosis is suppressed in catec1/catec1 mutant cells. Furthermore, expression of the proteinase isogenes SAP4-6 is no longer inducible in these mutant cells. The deletion of the CaTEC1 gene attenuates virulence of C. albicans in a systemic model of murine candidiasis, although both mutant and revertant cells that were prepared from infected tissues or the vaginal mucosa grew in a hyphal morphology in vivo. CaTEC1 complements the pseudohyphal and invasive growth defect of haploid and diploid S. cerevisiae tec1/tec1 mutant cells and strongly activates the promoter of FLO11, a gene required for pseudohyphal growth. This study provides the first evidence pointing to an essential role for a member of the TEA/ATTS transcription factor family that had so far only been ascribed to function during development as a virulence regulator in microbial pathogenesis.

Extracorporal shock wave therapy in patients with tennis elbow and painful heel

The aim of this study was to evaluate the effect of extracorporal shock wave therapy (ESWT) in tennis elbow and painful heel. Nineteen patients with tennis elbow and 44 patients with painful heel in which conservative treatment had failed underwent ESWT. Both groups received 3000 shock waves of 0.12 mJ/mm2 three times at weekly intervals. After a follow-up of 5 and 6 months respectively, pain measured on a visual analogue scale (VAS) decreased significantly in both groups. The success rate (excellent and good results) was 63% in tennis elbows and 70% in painful heels. ESWT seems to be a useful conservative alternative in the treatment of both conditions.

Chondral lesions after arthroscopic meniscus repair using meniscus arrows

Meniscus repair using bioabsorbable devices has become popular in the last few years. Good clinical results have been reported and few complications have been published. This report describes the case of a 37-year-old male patient with a lateral meniscus repair using 4 Meniscus Arrows (Bionx Implants, Blue Bell, PA). Postoperatively, repeated episodes of intra-articular effusions have occurred. A second-look arthroscopy 8 months after the reconstruction showed that the meniscus tear had not healed and revealed the presence of chondral damage corresponding to the location of the arrows in the posterior area of the lateral femoral condyle. Surgeons using the Meniscus Arrow should be aware of this possible postoperative complication.

[Tendinosis calcarea of the rotator cuff]

Calcifying tendinitis of the rotator cuff is a common disorder of the shoulder which affects mainly individuals between 30 and 50 years of age. The etiology is still a matter of speculation. The calcification is a reactive process actively mediated by cells in a viable environment. The deposit undergoes an evolution (precalcific stage--calcific stage with formative phase, resting period and resorption--postcalcific stage), which ultimately remodels normal tendon tissue. However, the evolutionary stages of the disease do not always follow the typical sequence. A symptomatic deposit may persist or postcalcific tendinitis develop. The treatment should be based on the knowledge of the natural history of the disease, which shows a strong tendency towards self-healing by spontaneous resorption of the deposit. The stage of evolution of the disease should be judged, combining pain history, morphology of the deposit on plain X-rays, and ultrasound findings. The therapeutic approach depends on the evolution of the disease. During the resorption phase we favor a conservative approach. For deposits which are not under resorption we propose a concept which consists of three steps: a conservative approach, extracorporal shock wave therapy (ESWT) or needling, and arthroscopic surgery. The efficacy of ESWT and needling has still to be proven. Patients with persisting pain after steps 1 and 2 are candidates for surgical removal of the deposit. We prefer the arthroscopic approach. In some cases an additional arthroscopic subacromial decompression (ASD) is indicated.

[Strategies for interventional revisions in failed anterior cruciate ligament reconstruction]

Anterior cruciate revision reconstruction is gaining more and more importance. Postoperative infection, a painful knee, limited range of motion and instability may make a second operation necessary. Results after revision ACL reconstruction are worse than results after primary ACL reconstruction. Analysis of the causes of failure and a therapeutic concept that is tailored to the individual case are preconditions for a successful reintervention. Revision ACL reconstruction has to be performed by an experienced knee surgeon who masters all the necessary techniques, from arthroscopy to arthrotomy and should be carefully planned.

The influence of avascularity on the mechanical properties of human bone-patellar-tendon-bone grafts

Our aim was to analyse the effect of avascularity on the morphology and mechanical properties (tensile strength, viscoelasticity) of human bone-patellar-tendon-bone (BPTB) grafts in vitro. These were harvested at postmortem and stored submerged in denaturated human plasma at a constant pH, pO2, pCO2, temperature and humidity under sterile conditions. Mechanical testing was performed two and four weeks after removal of the graft. The mean ultimate strength was 1085.7 +/- 255.8 N (control), 1009.0 +/- 314.9 N (two weeks cultured) and 1076.8 +/- 414.8 N (four weeks cultured). There was no significant difference in linear stiffness or deformation to failure between the groups. There was a difference in viscoelasticity between the control group and the avascular grafts and the latter had significant lower peak load-to-load ratios after 15 minutes compared with the control group. After two and four weeks the graft contained viable fibroblasts. There was regular cellularity in the superficial layers and decreased cellularity in the midportion. The structure of the collagen including the crimp pattern appeared to be normal in polarised light. We conclude that avascularity does not significantly affect ultimate failure loads or stiffness of BPTB grafts. Slight changes in viscoelasticity were induced, but the significance of the increased stress relaxation is not fully understood.

[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.

[Knee endoprosthesis: aspects of surgical techniques]

The implantation of a condylar knee has remained a challenge for surgeons and the equipment of the hospital. In contrast to total hip arthroplasty, not only is the correct insertion of the implant crucial, but also the treatment of the surrounding soft tissues. Mediolateral soft tissue balance and balance between flexion and extension gaps, as well as centering the patella, have to be done carefully. The soft tissue envelope of the knee joint is thin and prone to necrosis after multiple incisions. Damage to the extension mechanism can make a total joint useless. Tearing the patellar ligament from the tibial tuberosity must therefore be avoided by all means during operation. Precise cutting of the distal femur is only possible if excellent equipment is used by a skillful surgeon. The same is true for orientating saw cuts related to the long leg axes. These tasks can probably be taken over by navigation systems and robots in the future. Because the definite choice of implants has to be made intraoperatively, a complete modular system has to be present in the hospital. Only hospitals that can properly equip their surgeons to manage upcoming soft tissue problems and bony deficiencies should offer treatment to patients requiring condylar knee arthroplasty.

Cyclic testing of meniscal sutures

Suturing the meniscus has become a standard procedure for repairable tears. Studies investigating the outcome of meniscal sutures report a considerable rate of failures. Regarding the indications, which have been extended to the avascular zones, and regarding some accelerated rehabilitation protocols, the need for further in vitro investigations has become obvious. The aim of this study was to compare different meniscal suture types (vertical and horizontal mattress sutures) and materials (absorbable monofilament PDS 2-0, and nonabsorbable braided Ethibond 2-0 [Ethicon, Somerville, NJ]) under standard and cyclic loading conditions. Testing was performed on medial porcine menisci. In group A, specimens were tested to failure at a cross-head speed of 50 mm/minute. In group B, cyclic testing (100 cycles) was performed first within different load intervals (5 to 20 N and 5 to 40 N). Finally, the specimens were loaded until failure. In both groups, the failure loads were recorded and the failure modes were analyzed. In group A, there was no difference between suture type or suture material, with a mean failure load of 60 N. The failure modes were significantly different for vertical (100% suture failure) and horizontal sutures (50% suture failure) (P <.0001). In group B, 13% of the sutures failed under cyclic loading (7 with 40-N load, 1 with 20-N load). The gap of the sutured tear that appeared within the first load cycles was broader in horizontal sutures (P <.001). During the first cycles, the thread cut through the meniscus tissue and disappeared from the surface (partial tissue failure). There was no difference according to suture material. The ultimate failure loads after cyclic loading did not differ from the values of group A. These results show that meniscal sutures may fail under repetitive loading conditions and that a gap appears between the meniscal margins within the first loading cycles irrespective of the suture type and suture material used. The appearance of the gap and suture disappearance on the meniscal surface because of partial tissue failures (which were more pronounced in the horizontal sutures) confirmed the superior resistance of meniscal tissue to vertical sutures.

A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics

In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.

Ligament graft initial fixation strength using biodegradable interference screws

The objective of this study was to evaluate the initial fixation strength of three types of biodegradable interference screws [an Endo Fix, 7 x 25 mm polyglycolic acid, non-self-tapping (Acufex); a biodegradable interference screw, 7 x 23 mm poly-L-lactic acid, self-tapping (Arthrex); a Bioscrew, 7 x 25 mm poly-L-lactic acid, self-tapping (Linvatec)] in comparison to a titanium interference screw (Linvatec, 7 x 25 mm) in anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft. Porcine lower limbs were used. To control for specimen related bias, bone mineral density of each tibia was measured. All specimens were loaded to failure. Failure mode was determined by visual analysis. The maximum load to failure [mean (SD)] was 785 (87) N (titanium screw), 555 (60) N (Acufex), 592 (211) N (Arthrex), and 844 N (Linvatec). The primary fixation strength of the titanium screw and the Linvatec screw was significantly higher (p < 0.05) than the primary fixation strength of the Arthrex screw and the Acufex screw. There was no difference in bone mineral density between the groups. With respect to primary fixation strength, all biodegradable screws were strong enough to allow accelerated rehabilitation. From this point of view the biodegradable screws may be a reasonable alternative to titanium interference screws.

Cyclic AMP and fluconazole resistance in Saccharomyces cerevisiae

Cyclic AMP (cAMP) is involved in the stress response in Saccharomyces cerevisiae. We show that cAMP is required for resistance to fluconazole in S. cerevisiae. In addition, activation of Ras2, a regulator of cAMP generation, results in some protection from fluconazole toxicity in a fashion independent of the efflux transporter Pdr5p.

Evaluation of transarterial embolization for lower gastrointestinal bleeding

INTRODUCTION

Transcatheter arterial embolization has been used as a therapeutic maneuver for lower gastrointestinal bleeding. The availability of highly selective arteriography has made this procedure safer and warrants re-evaluation.

METHODS

A retrospective chart review was done of all patients undergoing arteriography for presumed lower gastrointestinal bleeding at two acute-care community hospitals. Causes of bleeding, clinical outcome, and complications caused by transcatheter arterial embolization were recorded.

RESULTS

There were 26 arteriographically identified bleeding sites in the colon and small bowel. The most frequent cause of bleeding was diverticulosis (12 patients), with the diagnosis being arterio venous malformation in two, and one unknown colonic source. Transcatheter arterial embolization was attempted for 17 separate bleeding episodes in 16 patients. Transfusion requirements were an average (+/- standard deviation) of 7 +/- 1.43 units per patient. Transcatheter arterial embolization was successful in stopping bleeding in 14 cases (82 percent). Two patients had surgery after transcatheter arterial embolization: one for colonic necrosis and one for persisting bleeding. There were two more unsuccessful procedures; one had a successful repeated transcatheter arterial embolization, and one stopped spontaneously. One patient rebled during the same hospitalization and was controlled with intra-arterial vasopressin. There were two deaths, both secondary to sepsis unrelated to the transcatheter arterial embolization or the gastrointestinal tract.

CONCLUSIONS

Transcatheter arterial embolization is a relatively safe and successful procedure in patients with massive lower gastrointestinal hemorrhage. It is an excellent choice of therapy for patients that are poor candidates for surgery, but its role in other patients remains to be defined.

Popliteal cyst accompanied by an intra-articular cartilage lesion in a child

The case of an 11-year-old girl presenting with a symptomatic popliteal cyst is described. There was no previous knee trauma nor could any inflammation be found. On MRI a concomitant retropatellar cartilage lesion had been detected preoperatively and was confirmed and treated by arthroscopy. The prevalence and treatment of popliteal cysts in children are discussed. Whereas in adults popliteal cysts are generally accompanied by intra-articular lesions, the presence of a concomitant intraarticular lesion in children is an extremely rare finding. We conclude that intraarticular lesions in the presence of popliteal cysts might have been underestimated as most of the studies regarding popliteal cysts in children were undertaken before the advent of arthroscopy, ultrasound, or MRI.

Age-related prevalence of rotator cuff tears in asymptomatic shoulders

To determine the prevalence of rotator cuff tears in asymptomatic shoulders we conducted a prospective clinical and ultrasonographic study of 411 volunteers. We anticipated an age-dependent outcome and divided the patients into 4 age-groups. Overall, we found evidence of a rotator cuff tear in 23% of the patients. In group 1 (aged 50 to 59 years), 13% (22 of 167) of the patients had tears; in group 2 (aged 60 to 69 years), 20% (22 of 108) of the patients had tears; in group 3 (aged 70 to 79 years), 31% (27 of 87) of the patients had tears; and in group 4 (age > 80 years), 51% (25 of 49) of the patients had tears. An astonishingly high rate of rotator cuff tears in patients with asymptomatic shoulders was thus demonstrated with increasing patient age. At this stage it remains unclear, however, which parameters convert an asymptomatic rotator cuff tear into a symptomatic tear. As a result, rotator cuff tears must to a certain extent be regarded as "normal" degenerative attrition, not necessarily causing pain and functional impairment.

[Extracorporeal shockwave therapy in tendionosis calcarea of the rotator cuff: comparison of different treatment protocols]

AIM OF THE STUDY

Extracorporeal shock wave therapy (ESWT) is a new therapeutic procedure for chronically painful calcifying tendinitis of the rotator cuff. The therapy may vary with the number of applied impulses or with impulse energy. Shock waves with an energy of 0.04 to 0.12 mJ/mm2 define low-dose ESWT, in contrast to high-dose ESWT (> 0.12 mJ/mm2). The aim of the study was to verify the hypothesis that either high-dose or low-dose ESWT could be effective if the total amount of applied energy was similar.

METHOD

Fifty patients were assigned at random to 2 groups. The treatment consisted of 3 x 5000 low-dose impulses without anesthesia (group 1) and 1 x 5000 high-dose impulses with intravenous analgesia (group 2). The patients were examined at 6 weeks, 3 and 6 months after treatment. X-rays were performed at each visit.

RESULTS

The Constant Score improved from 64.5 to 77.5 (group 1) and from 67.2 to 79.4 (group 2) before and 6 months after treatment (p < 0.05). The values on the visual analog scale which ranges from 0 (no pain) to 100 (maximal pain) improved from 76.8 to 48.8 (group 1) and from 75.4 to 45.6 (group 2) before and 6 months after treatment respectively. The final results for both Constant Score and visual analog scale were obtained after 3 months. X-rays showed a complete or subtotal calcific resorption in 8 (group 1, 32%) and 12 (group 2, 48%) patients.

CONCLUSION

Extracorporeal shock wave therapy may be an alternative treatment of calcifying tendinitis of the shoulder. Both treatment protocols gave equivalent results.

Prevalence of popliteal cysts in children. A sonographic study and review of the literature

Popliteal cysts in children differ from those in adults. They are considered to be less frequent and usually appear in the absence of intra-articular lesions. However, their prevalence in asymptomatic children is unknown. We present a prospective epidemiological study of 168 asymptomatic children under 15 years of age hospitalised for various pathologies. Children with knee problems and rheumatic diseases were excluded from the study. The children were examined ultrasonographically with a 7.5 MHz linear scanner. A popliteal cyst could be identified in 4 patients. The prevalence of asymptomatic popliteal cysts was thus 2.4%. For 2 of these patients, we obtained magnetic resonance image of the knee which showed no concommitant intra-articular pathology.

MAP kinase and cAMP filamentation signaling pathways converge on the unusually large promoter of the yeast FLO11 gene

In Saccharomyces cerevisiae, two major signal transduction pathways, the Kss1 MAPK pathway and the cAMP-regulated pathway, are critical for the differentiation of round yeast form cells to multicellular, invasive pseudohyphae. Here we report that these parallel pathways converge on the promoter of a gene, FLO11, which encodes a cell surface protein required for pseudohyphal formation. The FLO11 promoter is unusually large, containing at least four upstream activation sequences (UASs) and nine repression elements which together span at least 2.8 kb. Several lines of evidence indicate that the MAPK and cAMP signals are received by distinct transcription factors and promoter elements. First, regulation via the MAPK pathway requires the transcription factors Ste12p/Tec1p, whereas cAMP-mediated activation requires a distinct factor, Flo8p. Secondly, mutations in either pathway block FLO11 transcription. Overexpression of STE12 can suppress the loss of FLO8, and overexpression of FLO8 can suppress the loss of STE12. Finally, multiple distinct promoter regions of the FLO11 promoter are required for its activation by either Flo8p or Ste12p/ Tec1p. Thus, like the promoters of the key developmental genes, HO and IME1, the FLO11 promoter is large and complex, endowing it with the ability to integrate multiple inputs.

Resulting tensile forces in the human bone-patellar tendon-bone graft: direct force measurement in vitro

The objective of this study was to measure the resultant force in the human bone-patellar tendon-bone graft after reconstruction of the anterior cruciate ligament under various conditions in vitro. Seven fresh-frozen cadaver lower extremities were used. Force measurement was made with a quartz force transducer mounted in a specially designed load cell. The effect of passive extension movement, quadriceps pull, varus torque, and valgus torque on the resultant force in the ligament were investigated. Passive extension of the joint generated a rapid increase of force in the graft between 30 degrees and 0 degrees of flexion, reaching its maximum (128+/-25 N) at full extension. When quadriceps pull was applied to extend the joint, resultant force increased at 50 degrees of flexion and reached its maximum (219+/-25 N) at full extension. Additional resistance applied to the level of the ankle joint generated an additional load of the graft. Increase of forces in the ligament resulted from both varus and valgus applied moments.