A muCT analysis of the femoral bone stock in osteonecrosis of the femoral head compared to osteoarthrosis

INTRODUCTION

Long-term results of resurfacing in osteonecrosis of the femoral head (ONFH) are lacking and migration of the femoral component, necrosis of the femoral head and fracture of the femoral neck or head have been depicted. The aim of this study was to analyse the bone quality and 3-dimensional microarchitecture of the femoral head and neck in patients with ONFH compared to a group of patients with primary osteoarthritis (OA).

MATERIALS AND METHODS

muCT was used to compare the microarchitecture of the femoral head and neck in patients with ONFH (n = 10) and a control group of patients with primary OA (n = 10).

RESULTS

No statistical significant differences were found for bone volume and the bone volume fraction, the connectivity density and the structure model index in patients with ONFH and those with OA (P > 0.05). Patients with ONFH and those with OA had a similar trabecular number, thickness and separation (P > 0.05).

CONCLUSION

Based on our findings, we might conclude that hip resurfacing arthroplasty is a possible therapeutic option in the treatment of ONFH of the young and active patient and that an insufficient bone stock in ONFH seems not to be the deciding factor for failure. However, we just focussed on one of probably various factors. Further studies are needed to support these findings.

Differential transcriptome analysis of intraarticular lesional vs intact cartilage reveals new candidate genes in osteoarthritis pathophysiology

OBJECTIVE

To elucidate disease-specific molecular changes in osteoarthritis (OA) by analyzing the differential gene expression profile of damaged vs intact cartilage areas within the same joint of patients with OA of the knee using a combination of a novel RNA extraction technique and whole-genome oligonucleotide arrays.

METHODS

The transcriptome of macroscopically affected vs intact articular cartilage as determined by visual assessment was analyzed using an optimized mill-based total RNA isolation directly from the tissue and high density synthetic oligonucleotide arrays. Articular cartilage samples were obtained from patients with OA of the knee. Expression of differentially regulated genes was validated by real-time quantitative polymerase chain reaction and immunohistochemistry.

RESULTS

The amount of RNA obtained by the optimized extraction procedure was at least 1 microg per 500 mg of cartilage and fulfilled the common quality requirements. After hybridization onto HG-U133 Plus 2.0 GeneChips (Affymetrix), 28.6-51.7% of the probe sets on the microarray showed a detectable signal above the signal threshold in the individual samples. A subset of 411 transcripts, which appeared to be differentially expressed, was obtained when applying predefined filtering criteria. Of these, six genes were found to be up-regulated in the affected cartilage of all patients, including insulin-like growth factor binding protein 3 (IGFBP-3), wnt-1-inducible signaling protein 1 (WISP-1), aquaporin 1 (AQP-1), delta/notch-like EGF-repeat containing transmembrane (DNER), decay accelerating factor (DAF), complement factor I (IF).

CONCLUSION

The optimized methodical approach reported here not only allows to determine area-specific gene expression profiles of intraindividually different low-RNA containing OA cartilage specimens. In addition, this study also revealed novel genes not yet reported to play a role in the pathophysiology of joint destruction in OA.

Two year follow-up comparing computer assisted versus freehand TKR on joint stability, muscular function and patients satisfaction

Computer assisted (CAS) knee surgery has been established in clinical routine. There is still no study that investigates clinical outcome. Fifty patients who received a primary total knee replacement 2 years before were investigated. These patients were divided into two groups of matched-pairs; group A was operated in the freehand technique and group B with support of a computer system. We compared Womac score, Knee Society score, range of motion, leg alignment, knee stability and isokinetic muscle strength. We found similar results for WOMAC, Knee Society score and isokinetic muscle force. Stability and range of motion revealed slightly better values for the CAS group. A statistically significant difference could only be demonstrated for postoperative leg alignment. Two years after freehand versus computer assisted TKR we found slightly better values for range of motion and ligamentous stability. Only postoperative leg alignment was statistically better in the CAS group.

[Examination of the painful wrist]

The anatomy of the wrist is complex. Mechanical, neurological or systemic causes are responsible for a painful wrist. In many cases a specific diagnosis can already be made by taking a precise medical history. Physical examination includes inspection, palpation of landmarks and a dynamic examination in regard to joint regions. Plane X-Ray examinations are the basic tools in diagnostic imaging. Additional radiographic adjustments, ultrasound-, MRI- and CT-examinations may lead to more detailed information in special cases. A diagnostic arthroscopy is accomplished, if a pathological cause for wrist-pain with non-invasive methods cannot be found.

Electric efficiency of the erector spinae in high performance amateur tennis players

AIM

The aim of the paper was to evaluate neuromuscular activity patterns of the lumbar erector spinae during isometric voluntary maximum trunk extension and how this could be influenced through a back exercise home program in high performance amateur tennis players.

METHODS

Experimental longitudinal study of the lower back in a clinical setting. Seventy high performance amateur tennis players underwent isometric trunk extension tests in a specially built apparatus with simultaneous surface electromyography (EMG) recording from right and left lumbar erector spinae. Imbalance quotients were calculated using Electric Efficiency measures. Isometric and electromyographic changes were reviewed after a 7-week daily home program of back exercise.

RESULTS

Neuromuscular imbalance of the lumbar erector spinae associated with reduced Electric Efficiency, closely related to handedness was observed amongst tennis athletes at the start of the study. After a 7-week back exercise home program, lumbar neuromuscular imbalances were evened out and the Electric Efficiency of the erector spinae improved significantly at lumbar level L2 and L4. No significant difference was measured in maximal isometric trunk extension strength.

CONCLUSION

The asymmetric trunk loading caused by tennis specific biomechanics with trunk hyperextension motions and trunk rotation seems to induce imbalanced muscle activity patterns of the lumbar erector spinae. A home program of back exercises for tennis players can help to compensate for these imbalances, improves Electric Efficiency patterns of the erector spinae and should therefore be integrated in the daily training routine of high performance tennis players.

[Long-term results of synovectomy in the rheumatoid ankle joint]

Inflammatory rheumatic ankle joint destruction endangers the mobility of the rheumatic patient by pain and loss of function. In the presented patient population, 29 patients with a mean preoperative history of 14.3 years of rheumatoid arthritis and 7.6 years manifestation of ankle arthritis underwent open synovectomy of the ankle joint optionally combined with accompanying tenosynovectomy. Disease duration and the prevalence of radiological alterations (81% LDE 2-3) characterize the procedures as late synovectomies. The rate of 93% of additional tenosynovectomies and the prevalence of radiological alteration in the adjacent rear foot joints indicate a panarticular pathology of the rheumatic disease. A progression of the Larsen, Dale and Eek (LDE) grade was found in 62% of the ankle joints. The significant gain in the Kofoed ankle score (42.4 versus 55.9 points, p=0.042) was mainly caused by pain reduction and gain of mobility, whereas a decline of function was detected. Both genders showed comparable outcomes. The mean pain level on a visual analogue scale decreased from 7.6 to 3.3 (p<0.001) and 81.5% of the patients assessed the results of the synovectomy as good or very good.

The therapeutic use of osmotic minipumps in the severe combined immunodeficiency (SCID) mouse model for rheumatoid arthritis

OBJECTIVES

The viral gene transfer of interleukin 1 receptor antagonist (IL1ra) and interleukin 10 (IL10) into rheumatoid arthritis (RA) synovial fibroblasts (RASFs) has shown protective effects on cartilage destruction in the severe combined immunodeficiency (SCID) mouse model of RA. Nevertheless, side effects of viral transduction are possible and a number of cytokines or cytokine inhibitors are not available encoded in viral vehicles. As the production of viruses coding for bioactive proteins is cost and time intensive, we established an in vivo long-term release model using osmotic minipumps in the SCID mouse model for RA.

METHODS

Isolated RASFs were cultured for four passages and coimplanted together with human cartilage and an Alzet osmotic miniature pump model 2004, containing 200 microl of IL10 and IL1ra for 40 days in SCID mice. Implants were removed after 40 days and evaluated histologically. The actual rates of IL10 and IL1ra in murine serum were measured by ELISA.

RESULTS

Release of IL10 and IL1ra by the pumps was effective as both could be measured in significant amounts in the serum of the mice. IL10 and IL1ra release showed protective effects towards the coimplanted cartilage, similar to the adenovirally IL10/IL1ra-transduced RASFs. The mean (SD) invasion scores for the implants with the osmotic pumps were: invasion 0.7 (0.5), degradation 0.5 (0.3) (all parameters significant vs controls, p<0.05).

CONCLUSIONS

The results demonstrate that the combination of osmotic pumps with the SCID mouse model for RA can be used as approach for application and evaluation of cartilage-protective molecules. Furthermore, the effect of cartilage-protective cytokines is independent of the type of application.

[Percutaneous lumbar interbody fusion using autogenous osteoblasts in vivo]

AIM

In the present study we have investigated the potential of autogenous osteoblasts for osteoinduction in a spinal arthrodesis model.

METHOD

After posterolateral instrumentation of 3 segments of a sheep spine the intervertebral space was filled with cancellous bone, osteoblasts or left empty after nucleotomy and elimination of cartilage.

RESULTS

Radiological and histological analyses proved a significant osseous reaction in segments treated with cancellous bone or osteoblasts in contrast to the control segment. This outcome provides evidence of spondylodeses by spinal instrumentation in combination with osteoblasts in a sheep model.

CONCLUSION

The results suggest a possible application of autologous osteoblasts as an osteoinductor after percutaneous nucleotomy in spinal fusion. The possible application in a human model should be examined.

[Revision of the recommendations of the Commission on Pharmacotherapy of the German Society for Rheumatology. Comment on the use of Orthokin]

Due to the public discussion on the drug "Orthokin", the Commission for Pharmacotherapy of the German Society for Rheumatology (Deutschen Gesellschaft für Rheumatologie, DGRh) has summarized the relevant data. An unpublished study with 400 patients shows an advantage for Orthokin compared to either hyaluronic acid or a placebo for the treatment of osteoarthritis related chronic knee pain. Until these data have been published in an appropriate specialist journal, it is not possible for the DGRh to give a recommendation.

[Loosening of a total hip arthroplasty due to metastasis]

A case report of a metastatic caused loosening of a total hip arthroplasty one year after primary implantation is presented. A primary cancer was unknown at surgery. Due to suspected low-grade infection, a revision surgery was performed and the diagnosis of a metastatically caused loosening could be made. A bronchial carcinoma was identified as primary cancer. In spite of the rare incidence of the described metastatic loosening, the significance of a differential diagnostic strategy and the importance of a histological examination in revision surgery is depicted.

[Is there a correlation between the clinical, radiological and intrasurgical findings of osteoarthritis of the knee? A Prospective study on 103 patients]

AIM

The aim of this study was to compare the different diagnostic features (symptoms, physical examination, radiographic features and intraoperative findings) of osteoarthritis of the knee before total joint replacement and consequently relate them with each other.

METHOD

Patients with primary osteoarthritis of the knee, who where accepted for total joint replacement in our clinic, were integrated in our study. The medical conditions were recorded by using the Womac score, the knee subscore (KS) of the Knee Society Clinical Rating System and a visual analogue scale (VAS). A physical examination was also performed. The radiological evaluation was performed by using standardised radiographs. Joint space narrowing, subchondral sclerosis, osteophytes, knee alignment and the Kellgren score were recorded. During surgery an orthopaedic specialist documented the progression of cartilage lesions using the classification of chondromalacia described by Outerbridge. The analysis of correlation was performed by using the Spearman correlation (SpK) coefficient.

RESULTS

103 patients were integrated in the study (mean age: 68 years, 70 women). No significant correlation could be found between the Womac score or VAS and the results of the radiological examination (SpK [Womac - Kellgren score]: - 0.04; SpK [VAS - Kellgren score]: 0.08). There was a significant correlation between the KS and the results of the radiological examination as well as the progression of the cartilage lesions, caused by the results of the physical examination documented in the KS (SpK [KS - Kellgren score]: - 0.39). The radiographic features, with the exception of subchondral sclerosis, showed a significant correlation with the degree of chondromalacia (SpK [Kellgren score - chondromalacia]: 0.43). The amount of osteophytes correlated the most with the cartilage lesions: SpK: 0.43.

CONCLUSION

The knee subscore appears to be an efficient method for staging the clinical progression of osteoarthritis of the knee for clinical practice as well as for clinical trials. The Womac score especially serves to record the level of pain. We were able to confirm that the presence of osteophytes is the most significant radiographic feature of osteoarthritis of the knee. The Kellgren score turned out to be a reliable method for monitoring the radiographic progression of osteoarthritis of the knee.

[Minimally invasive total knee arthroplasty and navigation - a logical combination?]

The minimally invasive approach has been recommended for total knee arthroplasty by many surgeons and by industry in recent years, and patients now also expect it. The definition of a minimally invasive procedure is still the subject of some controversy. Some authors limit the length of the skin incision to 14 cm, while others propose the"least possible and barely adequate" approach. The main problem of the minimally invasive technique is still the increased risk of component malalignment owing to reduced visibility. As computer-assisted surgery has been shown in many studies to yield better component alignment than is obtained with the conventional technique, it seemed logical to use navigation systems in combination with the minimal invasive approach. The aim of this paper is to highlight and discuss the use of computer assistance with a minimally invasive approach.

[Minimally invasive injection therapy in lumbar syndromes]

Minimally invasive injection therapy is an effective approach for the treatment of sciatica with less complications. This therapy is a sufficient option in cases without absolute indications for operation.The paper describes in detail the different injection techniques like spinal nerve analgesia, epidural dorsal/perineural injections, vertebral joint infiltrations, and radiculographies.

[Current state of doing minimal invasive total hip replacement in Germany, the use of new implants and navigation--results of a nation-wide survey]

AIM

Total hip replacement has been developed to a very successful surgical procedure over 3 decades. In the last years many new helpful implants were introduced to the market, minimally invasive procedures were presented together with the technique of navigation. There is no scientific proof of the benefit of these procedures. The objective of this study was to collect data about the preferences of the surgeons for procedures and implants.

METHODS

In a countrywide anonymous survey, staff of 240 German trauma surgery and orthopaedic surgery departments were asked about their MIS procedures and their treatment strategies (August 2006).

RESULTS

184 of the questionnaires have been returned representing 64,569 THRs, 65% with cementless fixation, 12.6% with bone conserving implants and 4.1% with resurfacing. We found that 77% of the respondents were doing minimally invasive THR. 34% of all THR are minimally invasive (MIS) procedures, while 23% of the patients ask for MIS. Most of the surgeons (54%) define "minimally invasive" as the preservation of muscle, tendons and soft tissue, and 33% as the length of skin incision to be less than 10 cm. 78% are convinced that long-term survival is achievable even with less invasive methods. The most common MIS approach is the anterior/anterolateral (42%), for the standard procedure (not MIS) the dorsal approach is the most used (42%), and for revision surgery the lateral approach (44%). 77% of the respondents never use navigation and 54% are convinced that there is no sense in it. 75% of MIS surgeons use special MIS instruments: 97% use redon drainage, 48% the cell-saver, 71% of the operations are performed by senior/head surgeons. The assistant quota was largest in high-volume centres.

CONCLUSION

Innovative implants are used with care, more than one-third of all implants are still fixed with cement. MIS is performed in one-third of the THRs and it is not driven by sensationalised reports in the media. Even the surgeons' philosophy is oriented by long-term survival, most of them are defining MIS by preventing soft tissue damage and not by the length of skin incision. The transgluteal approach is still widespread, the drawbacks are hardly detectable, the soft tissue damage irreversible. Still lacking an adequate definition of the term "MIS", it is unclear whether the soft tissue is spared or the damage to it is the same under a smaller skin incision. Computer-aided surgery in THR is not used by most of the surgeons, for the majority it is not favourable.

[Radiological diagnosis of lumbar prolaps with quantitative and morphological criteria]

PURPOSE

The present study examines the differences of radiological diagnosis of lumbar prolaps with quantitative and morphological criteria. Advantages and disadvantages of both methods were analysed.

METHOD

Concerning the "Deutsche Wirbelsäulenstudie" (DWS) 286 male and 278 female patients between 25 and 70 years of age undergoing clinical or ambulant therapy for radicular symptoms and the diagnosis of a lumbar prolaps in CT and/or MRT were integrated into our study. Actual MRT and CT pictures of the patients' lumbar spine were analysed by an independent radiologist (primary radiologist). Radiological diagnosis was concerned with quantitative and morphological criteria. Radiological images of 100 selected patients were reexamined by another radiologist (secondary radiologist). On the basis of these results, the interobserver reliability (kappa) was calculated.

RESULTS

In 95.2% of all segments a prolaps was seen with quantitative and morphological criteria, in 4.5% a prolaps was analysed with quantitative and in 0.3% a prolaps was seen with morphological criteria. The radiological diagnosis of prolaps by quantitative criteria was confirmed by the operative findings. Many prolapses with lateral localisation were seen in these cases. Therefore radiological diagnosis on the basis of morphological criteria could be difficult. For both radiological methods similar interobserver reliabilities were calculated. To sum up both radiological methods are even equivalent. It is also possible to graduate the diagnosis with quantitative criteria. Detrimental effects of quantitative criteria could be difficulties in measurement with non-digital images.

CONCLUSION

Besides several recommendations in the international literature on the radiological analysis of prolaps with morphological criteria, diagnosis with quantitative criteria is also an effective method.

[Arthroscopic suturing of the rotator cuff. Placing of anchor, suturing and tying techniques]

Arthroscopic reconstruction of a rotator cuff tear is a demanding technique. Besides assessment and appraisal of the different types of tears, their mobilisation and, especially, secure refixation of the soft tissue are necessary if the operation is to be successful: suture anchors must be optimally placed, and suturing must be reliably achieved while the surgical field is viewed arthroscopically. A correct technique for arthroscopic knot tying after passage of the suture thread through the tendon is also essential for the holding strength of the sutures. The way the suture thread is tied during the arthroscopic procedure needs to be tailored to the individual situation. It is essential that the operator has mastered the technique of tying nonslipping knots, by alternating holding and connecting threads with the use of a knot-pusher. There is a vast number of published arthroscopic knots, and the one selected as suitable also needs to be adapted to the suture material.

[Current operative strategies for rotator cuff tears in German hospitals]

The surgical treatment of rotator cuff lesions is still a controversial subject. We therefore decided to perform a study designed to yield an overview of the treatment modalities currently applied in Germany. A nationwide questionnaire survey was sent to 470 orthopaedic and trauma departments to ask about their surgical treatment of rotator cuff lesions: frequency of operative treatment, methods used in diagnosis and types of operative treatment; particular attention was paid to the application of minimally invasive techniques and to postoperative rehabilitation. The response rate was 55%. In all, 30,462 arthroscopic treatments were recorded for the year 2004, 9,094 of which were open or mini-open techniques and 2,528 were endoscopic reconstructions of the rotator cuff. Overall, we found that arthroscopic rotator cuff repair was performed in only 111 of the 257 departments from which responses were received and that the majority of surgeons preferred to use sutured and nonresorbable anchors. The postoperative treatment varies widely, from the full range of motion allowed within the first postoperative week to substantially more restrictive regimens. We see that the arthroscopic repair is still not the standard treatment for rotator cuff lesions in Germany. Further research is clearly still needed especially in the area of postoperative treatment.

[Minimally invasive injection therapy for patients with radicular lumbar spine syndrome. First results of an minimally invasive treatment for patients with lumbar radiculopathy]

BACKGROUND

There are few studies on minimally invasive injection therapy (MIT) combined with multimodal conservative therapeutic options. Here, we evaluate the results of MIT in a clinical study.

METHODS

A total of 61 patients with radicular lumbar symptoms treated with MIT were examined before and 14.5 months after treatment. Subjective, objective, clinical and anamnestic parameters were considered.

RESULTS

In most cases, protrusions and prolapses were seen. Radicular pain, sensible and motoric deficits and also functionality of the spine could be rectified after MIT. No major complications were seen during treatment.

CONCLUSION

MIT is an effective approach with few complications for the treatment of patients with radicular syndromes.

Die konservative Therapie der aseptischen Femurkopfnekrose

Osteonecrosis of the femoral head is a locally destructive disease with a multifactorial genesis. The majority of patients are men between 35 and 45 years of age, who are increasingly reduced in their quality of life and career. As these patients are in the middle of their careers, osteonecrosis of the femoral head is even of increasing interest for the national economy. It is therefore of major interest to reduce the costs as well as the time for its therapy. Since conservative treatment is discussed controversially, it was the aim to focus on the current literature according to the criteria of evidence-based medicine and to prove the importance of conservative treatment of femoral head osteonecrosis.

[Navigated drilling for femoral head necrosis. Experimental and clinical results]

INTRODUCTION

In the early stages of osteonecrosis of the femoral head, core decompression by exact drilling into the ischemic areas can reduce pain and achieve reperfusion. Using computer aided surgery, the precision of the drilling can be improved while simultaneously lowering radiation exposure time for both staff and patients. We describe the experimental and clinical results of drilling under the guidance of the fluoroscopically-based VectorVision navigation system (BrainLAB, Munich, Germany).

MATERIALS AND METHODS

A total of 70 sawbones were prepared mimicking an osteonecrosis of the femoral head. In two experimental models, bone only and obesity, as well as in a clinical setting involving ten patients with osteonecrosis of the femoral head, the precision and the duration of radiation exposure were compared between the VectorVision system and conventional drilling.

RESULTS

No target was missed. For both models, there was a statistically significant difference in terms of the precision, the number of drilling corrections as well as the radiation exposure time. The average distance to the desired midpoint of the lesion of both models was 0.48 mm for navigated drilling and 1.06 mm for conventional drilling, the average drilling corrections were 0.175 and 2.1, and the radiation exposure time less than 1 s and 3.6 s, respectively. In the clinical setting, the reduction of radiation exposure (below 1 s for navigation compared to 56 s for the conventional technique) as well as of drilling corrections (0.2 compared to 3.4) was also significant.

CONCLUSIONS

Computer guided drilling using the fluoroscopically based VectorVision navigation system shows a clearly improved precision with a enormous simultaneous reduction in radiation exposure. It is therefore recommended for clinical routine.

[Knowledge transfer and student's satisfaction in orthopaedics--a survey of 476 students]

AIM

The aim of the current study was to find out about the student's growth of knowledge and satisfaction in orthopaedics. We performed a survey among 476 students of one faculty.

METHOD

We performed an anonymous survey in which the students had to answer a questionnaire which consisted of items according to knowledge in orthopaedics, subjective satisfaction and according to the difficulty of the asked questions.

RESULTS

74% of students disliked the so-called "hammerexam." 56% believe that the transfer of knowledge is good in lectures and bedside teaching courses. 20% prefer to cancel the "hammerexam," 30% would prefer to spend more time for important sections such as surgery and internal medicine and 20% would prefer it if the practical aspects of medicine were placed in the foreground. During the third and fourth semesters, the increase of knowledge is at its highest but is reduced later. 4% of all asked students are planning to become orthopaedic surgeons.

CONCLUSION

Our study demonstrates that good knowledge transfer within the modified lectures and bedside teaching lessons is achieved. Student satisfaction is high. Only very few students are critical about their current situation.

[Neuromuscular imbalances of the lower back in tennis players--the effects of a back exercise program]

SUMMARY BACKGROUND DATA

Tennis players asymmetrically load the trunk while playing. Neuromuscular imbalances are risk factors for low back injuries. The association between neuromuscular activity patterns of the lower back and back exercise has not been researched yet.

METHODS

Simultaneous maximum isometric trunk extension test and surface-electromyographic recordings from lumbar erector spinae in 82 amateur tennis players in a specially built apparatus before and after a seven-week back exercise home program.

RESULTS

Left-right neuromuscular imbalances of lumbar erector spinae were present amongst 48 (58.5 %) out of 82 tennis athletes, statistically closely related to handedness. Within the training group (n = 70), neuromuscular imbalances of erector spinae were significantly evened out without a significant increase of maximum trunk extension strength. No such effects were detected within the control group (n = 12).

CONCLUSION

Tennis specific biomechanics seems to predispose to lumbar neuromuscular imbalances. A back exercise program for tennis player can significantly even out those imbalances.

[Are computer assisted total knee replacements more accurately placed? A meta-analysis of comparative studies]

Computer-assisted surgery (CAS) has become established in many hospitals throughout the world, especially in the form of computer navigation for total knee replacement (TKR). Analysis of the studies available revealed 18 comparative studies examining the precision of implantation of knee endoprostheses following CAS and after implantation by the conventional technique. In a meta-analysis of 13 studies in which the same safe zone of +/-3 from neutral alignment was defined for the leg axis, a total of 1,784 TKR were performed. In the group of patients in whom the conventional technique was used, 75.6% (654/865) of TKR were implanted within the safe zone. In the CAS group 93.9% (863/919) of the prostheses were implanted within the safe zone (p<0.0001). The differences between the groups were statistically significant in 11 of the 13 studies, and the difference between groups for the entire patient population is highly significant. Only limited clinical results were ascertained in these comparative studies; there were no great differences between the treatment groups in clinical course.