[Medial Unicompartmental Knee Arthroplasty Using Patient-Specific Instrumentation - Accuracy of Preoperative Planning, Time Saving and Cost Efficiency]. / Unilaterale mediale Schlittenprothesen mit patientenspezifischer Instrumentierung - Planungsgenauigkeit, Zeitersparnis und Kosteneffektivität.

BACKGROUND: In the past few years, patient-specific instrumentation (PSI) in knee endoprosthetics has been energetically marketed. PSI can enhance the accuracy of the size and alignment of the prosthesis components. It should also be possible to reduce hospital costs and operating time. It remains unclear whether these putative advantages are achieved in medial unicompartmental knee arthroplasty (UKA). PATIENTS/MATERIAL AND METHODS: Data from 22 patients (24 knees) were analysed retrospectively. The focus was on the reliability of preoperative surgical planning - particularly with regards to the level of experience of the five surgeons involved, who were split into two groups depending on their level of experience, as defined by EndoCert®. Another focus was on the evaluation of actual surgical time and cost effectiveness using PSI. RESULTS: In order to achieve an optimal outcome, preoperative surgical planning had to be modified intraoperatively to a great extent. The femoral component had to be adjusted intraoperatively in 41.7 % of all cases, the tibial component in 58.3 % and the polyethylene insert in 87.5 %. Surgeons equipped with less experience had to change preoperative planning more often than the more experienced surgeons. Utilising PSI increased the operating time of both the less experienced and the more experienced surgeons. PSI planning and lack of surgical experience were the main predictors of increased surgical time. Instead of lowering costs, utilizing PSI increased surgical costs by nearly 1300 $ per case. This was due to increased operating time, license fees and extraordinary expenditure for MRI scans. CONCLUSION: The advertised advantages of PSI were not supported by the data analysed. On the contrary, this technology leads to additional costs, greater operating time and insufficient accuracy in preoperative planning. As not a single study has yet demonstrated better outcomes in terms of alignment and/or function with PSI than with standard instrumentation, additional data are required before PSI can be recommended for routine use in medial UKA.

[Inter- and intraobserver reliability in Graf's sonographic hip examination]. / Inter- und intraindividuelle Messabweichungen in der Säuglingshüftsonografie nach Graf.

AIM: Inter- and intraobserver reliability and learning curve using Graf's ultrasonographic hip examination were assessed. MATERIAL AND METHODS: 189 participants of the basic, advanced and final courses on hip ultrasound using the Graf method (DEGUM) were asked to answer a questionnaire and to measure 34 normal and pathological sonographic hip examinations. Measurement differences and the learning curve during the different courses were evaluated. RESULTS: There was a significant (p = 0.001) improvement of the average angle between the basic (6.74 degrees [+/- 1.46 degrees ]) and the advanced course (6.22 degrees [+/- 1.17 degrees ]). However, there were no better results in the final course and no additional improvement. Participants had higher variations when measuring the beta-angle than the alpha-angle. A significant improvement was seen if the participants performed a large number of hip ultrasounds between the courses. Higher measurement differences were seen in pathological hip ultrasounds and in ultrasonographic examinations of poorer quality. CONCLUSIONS: During the educational courses on hip ultrasound using the Graf method, a high intra- and interobserver variability was seen. These findings were most prominent in measurement of the beta-angle, in pathological hip ultrasounds and in ultrasonographic hip examinations of poorer quality. The best results were achieved by participants who had performed a large number of examinations between courses. For the improvement of ultrasonographic measurements, a large number of self-performed examinations and a training in potential mistakes seem to be of great importance.

[Three-dimensional techniques in orthopedic ultrasonography]. / Dreidimensionale Ultraschalltechniken.

Three-dimensional ultrasonography is not yet an established method in soft tissue and joint diagnostics as it is in obstetrics. Although a spatial view on the object is fascinating, problems occur in handling. No standard is defined for acquisition or visualisation. For the acquisition of the volume mainly 3D-arrays and image correlation techniques are used. For visualisation planar views of sections out of the volume, but also spatial views in a transparency or surface mode are used. Investigations on feasibility for soft tissue or joints show a higher accuracy, validity and reproducibility for 3D-sonography. Due to the low differences of the acoustic impedance visualisation is confusing in a transparency mode and needs a time consuming postprocessing in a surface mode. Future developments address to the field of faster acquisition ("real time 3D"), higher geometric precision and easier visualisation by automated segmentation. By the three-dimensionality of the data set applications in telematics, navigation and simulation ("sonographic training") are expected.

High tibial osteotomy versus unicompartmental joint replacement in unicompartmental knee joint osteoarthritis: 7-10-year follow-up prospective randomised study.

The clinical outcome of patients treated either by high tibial osteotomy or unicompartmental arthroplasty for medial unicompartmental osteoarthritis of the knee was compared in a prospective randomised study. In total, 32 patients received a high tibial osteotomy (HTO) and 28 patients a unicompartmental arthroplasty (UKA). More intra- and postoperative complications were observed after HTO. Patients were assessed at an average of 2.5 (1.6-5), 4.5 (3.6-7), and 7.5 years (6.6-10) after the operation. Using the Knee Society Score, 71% (15) of patients after osteotomy and 65% (13) after replacement had a knee score of excellent or good 7-10 years postoperatively. The Kaplan-Meier survival analysis 7-10 years postoperatively showed a survivorship of 77% for UKA and 60% for HTO. Although the unicompartmental prosthesis used in this series has not shown promising results, we conclude that with the advanced design of unicompartmental prosthesis today, UKA offers better long-term success.

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

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

3-D visualization of the newborn's hip joint using ultrasound and automatic image segmentation.

Graf's method has been established as a standardized procedure for the diagnostic screening of developmental dysplasia of the hip in newborns. In this procedure, a two dimensional ultrasound image that has to contain standardized landmarks is taken and evaluated interactively to calculate congruence indicators. Since these indicators are only derived from a 2-D scan, they do not reflect the spatial joint structure. In our study, we visualized three dimensional scans of newborns' hip joints that were obtained using a conventional ultrasound transducer and a commercial localizer system that was fixed to the scanhead. The landmarks were detected by automatic image segmentation to avoid examiner dependent findings. The landmark structures as well as an automatically determined virtual sphere approximating the femoral head were visualized color coded on a computer screen. This kind of visualization was found to be intuitive. The evaluation of the entire joint geometry and the 3-D relations between the acetabulum and the femoral head improves the reliability of the diagnostics.

Pilot study of total knee arthroplasty planning by use of 3-D ultrasound image volumes.

The incidence of Total Knee Arthroplasties (TKA) is increasing. The main problem is the correct placement of especially the femoral prosthesis. Pre-operative planning and intra-operative realization relies on lower limb X-rays and extra- or intramedullary devices. This may lead to implant displacements. We generated virtual models of the distal femur for 10 knee joints. In a free-hand sweep we recorded 3-D US image volumes, which typically took 90 sec. The bony structures were detected automatically in the US-images and then appeared as curvilinear lines. Spatially arranged these lines formed femur models, which were used for the placement of a femoral prosthesis in an interactive computer-based 3-D planning. The automatic image segmentation took about 45 minutes. Its analysis showed correct detection of the bone surface. The interactive planning took 5-10 minutes. The investigation demonstrates that 3-D US can provide data of position and size of bony structures. Bone models created by analysis of 3-D US image volumes are useable for simulation of TKA implantations.

[Ultrasound hip joint screening in newborn infants. Correlation of anamnestic risk factors and hip dysplasia]. / Sonographisches Hüftgelenk-Screening bei Neugeborenen. Korrelation von anamnestischen Risikofaktoren und Hüftdysplasie.

BACKGROUND: Congenital dysplasia of the hip (CDH) is the most frequent inborn deformity of the locomotor apparatus. Hereditary, pelvic respectively breech presentation or abdominal delivery, premature as well as post-term birth and twin pregnancy are considered to be anamnestic risk factors for congenital dysplasia of the hip. The results of ultrasound hip screening from July 87 until December 94 are presented with special regard to the correlation of these risk factors and the occurrence of pathologic hips. PATIENTS: 19 different orthopaedic surgeons examined the hips of 3739 newborns (female: 1837-49.1%; male: 1902-50.9%) by ultrasound (screening). 96% of the examinations were performed within a period of 5 days after birth, in a few cases the babies were up to 19 days old. METHOD: The ultrasound examinations, the assessment of the echograms and classification into types of hip were performed according to Graf's technique. Two types of ultrasonographs were used: SL-1, Siemens--5 MHz scanner; LSC 7500, Picker--7.5 MHz scanner). All investigations were assessed retrospectively over the period of time with the help of documentation forms (data of newborn baby, case history, clinical and sonographical findings, kind of therapy and procedure) and statistically checked (program SPSS 7.5, Chi-Quadrate-Test, logistic regression). RESULTS: In 239 children (6.4%) we found hips required therapy respectively control investigations (type IIa, alpha < 55 degrees or worse; Graf's classification). For the entire group we achieved the following types of hips (right/left side): Ia--214 (5.7%)/224 (6.0%); Ib--2069 (55.3%)/2008 (53.7%); IIa (> or = 55 degrees)--1318 (35.3%)/1322 (35.4%); IIa (< 55 degrees)--65 (1.7%)/74 (2.0%); IIc--45 (1.2%)/71 (1.9%); D--18 (0.5%)/30 (0.8%); IIIa--8 (0.2%)/7 (0.2%); IIIb--1 (< 0.1%)/2 (0.1%); IV--1 (< 0.1%)/1 (< 0.1%). With regard to the risk factors the distribution was as follows: hereditary--302 babies (8.1%), pelvic respectively breech presentation--149 (4%), abdominal delivery--359 (6.5%), premature birth--188 (5.0%), post-term birth--164 (4.4%), twin pregnancy--73 (2%). CONCLUSIONS: In newborn babies with cases of hip dysplasia in their family (heredity) and pelvic respectively breech presentation at birth we found a significant higher rate (p < 0.05) of hips required therapy respectively control investigations (type IIa, alpha < 55 degrees or worse; Graf's classification). Also, for girls and the left hip a significant higher rate was achieved. A correlation of the other mentioned risk factors abdominal delivery, premature and post-term birth as well as twin pregnancy was not evident.

[Standardized sonographic investigation of the lumbar spine in 247 newborns]. / Standardisierte sonographische Primäruntersuchung der lumbalen Wirbelsäule bei 247 Neugeborenen.

Open dysraphism is generally known before birth due to prenatal screening but occult spinal malformation often remains unrecognized. Nevertheless, newborns with occult dysraphism could be easily diagnosed by ultrasound, which might be performed additionally to the neonatal screening of the hips. Early surgical treatment or close neuropediatric follow-ups could be administered as a consequence. As part of a prospective study-design, we screened the spinal cord of 247 newborns by ultrasound. Parents were interviewed about a positive family history, a folate intake during pregnancy, amniocentesis or chorionbiopsy. Clinically, cutaneous stigmata usually associated with occult spinal dysraphism were evaluated. An orthopedic and pediatric examination followed. The sonographic investigation was done in prone position using a newly designed positioning device. The sonographic examination was performed within 5 minutes and longitudinal and transversal pictures were taken for documentation. In all of the 247 examined newborns we were able to visualize the cartilageous structures of the spinal cord and the dural sack detailly. Dependent on the position of the newborn, variations of the width of the dural sack could be noted. Thus a newly designed positioning device helped to standardize the examination situation. We did not find any pathological changes of the spinal cord. Nevertheless ultrasonography provides a useful diagnostic tool in investigating the newborn where occult spinal dysraphism is expected.

[Ultrasound imaging of congenital knee joint dislocation. Value in diagnosis and therapy]. / Die sonographische Darstellung der kongenitalen Kniegelenksluxation. Stellenwert in Diagnostik und Therapie.

Congenital dislocation of the knee is a uncommon malformation. Frequently there is an association with other congenital deformities including congenital dislocation of the hip. The classification of Leveuf and Pais into three separate groups (Type A, Type B, Type C) is now widely accepted. Between October 1989 and April 1995 we evaluated ten children (five girls and five boys) with twelve dislocated knees. Clinical, radiographic and different ultrasonography examinations were carried out on both knees. The sonographic classification showed Type A in 3, Type B in 5 and Type C in 4 cases. The sonographic examination revealed the essential anatomic structures and their pathomorphology. The anterior and the posterior cruciate ligament could be demonstrated in the majority of the cases. Three dislocated knees showed an obliteration of the recessus suprapatellaris and fibrotic changes in the m. quadriceps. These cases required operative treatment. With conservative treatment we achieved a satisfactory result in eight children with nine disease knees. There was a good functional result with an average flexion of 106 degrees. Early conservative treatment recommend as the therapy of choice. Ultrasonography imaging offers the possibility of reliable differentiation into one of the three groups of the classification of Leveuf and Pais. Radiographic documentation during the therapy has become the exception. Ultrasonography imaging helped substantially in the decision making and the timing of operative treatment.

[Magnetic resonance tomography in therapy follow-up after repositioning treatment of congenital hip dislocation]. / Die Magnetresonanztomografie als Therapiekontrolle nach Repositionsbehandlung bei kongenitaler Hüftluxation.

INTRODUCTION: After treatment of infantile hip dislocation in terms of reduction and retention in plaster casts or splints a problem of therapy controlling exists. To assess if the femoral head is in correct position centered in the socket ultrasound is not possible, because one cannot achieve the necessary standard position. Computertomograms are associated with a hereditary taint of radiation and plain roentgenograms lack of presentation of the important cartilaginous structures. METHOD: To control infantile hips after open or closed reduction from 1990 until 1996, 43 examinations by MR imaging were performed in 34 children. RESULTS: In our series MRI was able to provide exact information about the position of the femoral head independently of its state of ossification. Also, a clearly visualisation of the different structures of the acetabular fossa, particular acetabulum, pulvinar, bony and cartilaginous acetabular rim and limbus was possible. Furthermore the MR images showed interpositioned soft tissue, intraarticular effusion and displayed cartilaginous parts of the acetabular rim. CONCLUSIONS: MRI is an exact method to assess the anatomical and pathological conditions of the childlike hip joint. Because of the disadvantages of CT and X-ray, MRI is superior in terms of controlling the results after treatment of infantile hip dislocation.

[Ultrasound hip joint screening in newborn infants. Is twin pregnancy a risk factor for dysplasia?]. / Sonographisches Hüftgelenk-Screening bei Neugeborenen. Ist die Zwillingsschwangerschaft ein Dysplasie-Risikofactor?

PURPOSE: This study aimed at investigating whether twin pregnancy is a risk factor for congenital dysplasia of the hip. METHOD: From 1987 until 1994 the hips of 3739 (1902 male, 1837 female) newborn were examined by ultrasound (screening) according to Graf's technique. We compared the results of twins and the other newborn (non-twins). The examinations were performed by 19 physicians. 73 (2%) of the newborn were twins (29 male, 44 female). RESULTS: In the group of 3666 non-twins we found the types of hip IIa (alpha < 55 degrees) to IV (Graf's classification) in 237 (6.5%) newborn: 136 (3.7%) right side/183 (5.0%) left side. Only 2 (2.7%) of the 73 twins showed these types of hip. We found 4% (149/3739) breech presentations at birth in the entire group. 3.9% (141/3666) in the group of non-twins and 11% (8/73) cases in the twin group. 5.2% (190/3666) of the non-twins and 2.7% (2/73) of the twins required a treatment with abduction orthosis or Pavlik harness. CONCLUSION: This report shows that the types of hip IIa (alpha < 55 degrees); IIc; D; IIa, IIb and IV according to Graf and a required treatment in twins was significantly not more frequent than in the other newborn (non-twins), although twins showed more often a breech presentation at birth. The different kind of breech position in twins (hips and knees in flexion, legs and feet parallel) and non-twins (hips in flexion, knees in extension) could be one reason for these results. Besides, non-twins assume their breech position earlier than twins with a consecutively longer period of time of mechanical stress on the hips.

[Ultrasound neonatal screening: the effect of anamnestic risk factors on hip dysplasia]. / Sonographisches Neugeborenen-Screening: Der Einfluss anamnestischer Risikofaktoren auf die Hüftdysplasie.

INTRODUCTION: Hereditary, pelvic respectively breech presentation or abdominal delivery, premature as well as post-term birth and twin pregnancy are considered to be anamnestic risk factors for congenital dysplasia of the hip. The results of ultrasound hip screening of two University hospitals are presented with special regard to the correlation of these risk factors and the occurrence of pathologic hips. PATIENTS/METHODS: 24 different physicians of the orthopaedic departments examined the hips of 6617 newborns (female: 3253--49.2%; male: 3364--50.8%) by ultrasound (screening). 94.6% of the examinations were performed within a period of 5 days after birth. The ultrasound examinations, the assessment of the echograms and classification into types of hip were performed according to Graf's technique. All investigations were assessed retrospectively over the period of time with the help of documentation forms (data of newborn baby, case history, clinical and sonographical findings, kind of therapy and procedure) and statistically checked (Chi-Quadrate-test). RESULTS: In 436 children (6.6%) we found hips required therapy respectively control investigations (type IIa, a < 55 degrees or worse; Graf's classification). For the entire group we achieved the following types of hips (right/left side): Ia--724 (10.9%)/645 (9.8%); Ib--3931 (59.4%)/3892 (58.8%); IIa (> or = 55 degrees)--1733 (26.2%)/1768 (26.7%); IIa (< 55 degrees)--143 (2.2%)/181 (2.7%); IIc--55 (0.8%)/77 (1.2%); D--20 (0.3%)/39 (0.6%); IIIa--9 (0.1%)/11 (0.2%); IIIb--1 (< 0.1%)/3 (0.1%); IV--1 (< 0.1%)/1 (< 0.1%). CONCLUSIONS: In newborn babies with cases of hip dysplasia in their family (heredity) and pelvic respectively breech presentation at birth, as well as for girls and the left side we found a significant higher rate (p < 0.05) of hips required therapy respectively control investigations (type IIa, alpha < 55 degrees or worse; Graf's classification). A correlation of the other mentioned risk factors premature respectively post-term birth, twin pregnancy and cases of abdominal delivery without breech presentation was not evident.

[Effect of surgical technique on meniscus transplants. A histological, animal experiment study]. / Der Einfluss der Operationstechnik auf Meniskustransplantate. Eine histologische, tierexperimentelle Studie.

After transplantation, a meniscus undergoes alterations in mechanical loading, which causes changes in its histological structure. We studied the degenerative effects on meniscus and tibial cartilage resulting from variations in the congruity or the isometric fixation of medial meniscus transplants. In three groups of five sheep each, the menisci were transplanted in three different ways, using the same operative approach. The menisci were evaluated 24 weeks after operation. In group 1, the meniscus was totally detached from its base at the capsule and refixed without changes in the congruity or isometry. This group provided the basic data. In group 2, the contralateral medial meniscus was turned upside down and transplanted. The reattachment was performed according to isometric conditions. With this technique the congruity of the tibial and femoral surface was modified. In group 3, the medial meniscus was reimplanted by choosing defined non-isometric fixation points for the anterior and posterior meniscal ligaments without changing the position of the corpus. For evaluation, the morphological alterations of meniscus and tibial cartilage were assessed by the Jackson score. The more distinct changes of the meniscus were assessed histologically by three criteria: surface cells, surface fibers and changes in the meniscus center. The highest degree of degenerative changes occurred in group 3 (score 4.5); however, considerable changes were also found in group 2 (score 3.5). Incongruous or non-isometric placement of a meniscal graft will lead to degeneration and failure of the graft.

[Perthes disease--results of a containment-oriented therapy concept]. / Morbus Perthes--Ergebnisse eines am Containment orientierten Therapiekonzepts.

INTRODUCTION: In a retrospective study a treatment concept for Perthes' disease dependent on the containment was applied. PATIENTS/METHODS: 49 hips of 41 children (9 female, 32 male) were treated between 01. 01. 1990 and 31. 12. 1995. In our concept of treatment a varus femoral osteotomy was performed in 28 cases with not contained hips or less than 4/5 coverage of the femoral head (X-ray/MRI). The other 21 well contained hips with 4/5 coverage or more were treated conservatively with physiotherapy and in case of joint effusion and pain additionally with the use of crutches (partial weight bearing) and anti-inflammatory medication. The average age in the non-operative group at the time of first investigation was 4 years and 9 months (3 y./1 m. to 7 y./1 m.) and 6 years and 3 months (4 y/2 m. to 10 y/0 m.) at our last examination (mean follow up 17.7 months, range of 6 to 72 months). At the time of indication for a varus femoral osteotomy the patients had an average age 6 years and 1 month (3 y./6 m. to 10 y./2 m.), the mean age at the last postoperative examination was 7 years and 11 months (4 y./8 m. to 12 y./5 m.) with an average follow up of 21.5 months (6 to 77 months). RESULTS: For the conservatively treated children we achieved good results (still well contained hips with 4/5 coverage, no decrease of function, no increase of pain) in 85.7% (18 of 21 cases). In 85.7% (24 of 28 cases) we found good results (well contained hips, increase of coverage, no decrease of function, no increase of pain) in the operation group. CONCLUSIONS: The presented concept of therapy in Perthes' disease was practicable for all patients and included the possibility of decision for operative or non-operative treatment. In both groups we achieved good results in 85.7% of the cases.

[Meniscus replacement using incongruent transplants--an experimental study]. / Der Meniskusersatz mit inkongruenten Transplantaten--eine experimentelle Untersuchung.

The effect of incongruous medial meniscal grafts on the articular surface was studied. We compared the cartilage degeneration in 4 Groups of 25 sheep knees. The histological changes were graded according to the score of Mankin, the morphological alterations by the score of Jackson. In Group 1 no surgery was performed. In group 2, the meniscus was totally detached from its base at the capsule and refixed without changes in the congruity or isometry. This group provided the basic data. In group 3, the contralateral medial meniscus was used as a transplant by reversing it. The reattachment was done according to isometric conditions. With this technique only the congruity of the tibial and femoral surface was modified. In group 4, the medial meniscus was completely removed. The results of group 1 (Mankin grade 0.58; Jackson grade 0.00) and group 2 (grade 0.50 and 0.47) showed no difference. The highest degree of degenerative changes occurred in the meniscectomized knees (group 4, grade 4.47 and 1.73), however considerable changes were also found in the knees with an incongruous meniscal graft (group 3, grade 3.37 and 1.27). The results suggest that incongruous grafts will lead to degeneration of the articular surface but still have a chondroprotective effect.

[New approaches to 3D-ultrasonographic imaging of infant hips]. / Neue Ansätze zu einer 3D-sonographischen Darstellung der Säuglingshüfte.

Ultrasound of the infant hip is an established method in the diagnosis and monitoring of the treatment of congenital dysplasia of the hip (CDH). Its use as a screening method for CDH, early diagnosis and start of therapy results in a high success rate and reduces the length of the therapy. According to Graf's technique, the examination findings are taken from a standard plane. Assessment of the examined hip joint is based on information obtained from this standard intersection plane, which has to be representative for the whole joint configuration. Furthermore, the method according to Graf requires a very expert examiner. We report on a new approach to three dimensional ultrasound of the infant hip for covering and demonstrating the complete dimensions of CDH. A maturity disorder of the infant hip located outside the standard plane should be recognized by 3D ultrasound. In contrast to already existing 3D ultrasound systems with specially constructed transducers, we use a position sensor which, in conjunction with a video tape recorder, an external computer and the corresponding software, is able to support normal ultrasound equipment. A common 7.5 or 5 Mhz linear transducer can be used. During the examination, the form and size of the femoral head is automatically analysed. The result is placed as a virtual sphere into the 3D data set. The quality of the examination should be independent of the examiner's skill.

[The use of lasers in surgical orthopedics. A current review]. / Die Anwendung des Lasers in der operativen orthopädie. Eine aktuelle Ubersicht.

In laser-assisted arthroscopic knee surgery, clinical outcome and experimental results are quite different. After laser treatment of local chondromalacia, large cartilage lesions with less tendency towards repair were more often seen than after conventional arthroscopic treatment. Therefore, laser treatment of chondromalacia cannot be recommended. Compared with conventional meniscectomy, laser-assisted meniscal surgery has some advantages, but there is also some risk of inducing gonarthrosis. Some studies show a good hemostatic effect of the laser and the feasibility of precise tissue cutting. On the other hand, laser treatment causes alteration of the tissue. The meniscal tissue becomes stiffer, which may promote the manifestation of gonarthrosis. Percutaneous laser disc decompression has been in successful clinical use since 1986 in the treatment of intervertebral disc prolapses. Studies of multiple orthopedic departments worldwide show a success rate of 75%. To guarantee the success the indications must be observed. The use of lasers in the arthroscopic treatment of outlet impingement syndrome have some advantages, too. The outcome is better than that of other arthroscopic techniques and there are fewer complications because of the hemostatic effect and the improved vision. Laser-assisted capsular shrinkage combined with arthroscopic labrum reattachment allows conventional laser use. Capsular shrinkage can be achieved with low-level laser energy. If this treatment is not successful, other operative techniques can be performed without restrictions.

[The value of leukocyte scintigraphy in suspected implant infection in patients with chronic polyarthritis]. / Nutzen der Leukocytenszintigraphie bei Verdacht auf Implantatinfekt bei Patienten mit chronischer Polyarthritis.

When infection of implants is suspected, optimal management requires accurate confirmation or exclusion of infection. However, in spite of demonstrative clinical signs cultures of smears or chemical parameters of inflammation frequently are ambiguous. Scintigraphy with indium-labeled white blood cells (WBC) has been reported to be sensitive and specific in the diagnosis of low-grade sepsis of the musculoskeletal system. Twenty-eight patients with possible infection were prospectively studied. Infection was suspected in 19 cases with total hip joint prosthesis, 14 cases with knee joint prosthesis and 1 case with shoulder joint prosthesis. All of them underwent scanning with indium-111-labeled WBC and subsequently underwent surgery. At surgery infections were determined by means of culture or histologic results. When correlated with culture and histologic results sensitivity of 111-indium-WBC imaging was 89% with a specificity of 67% and a predictive accuracy of 77%. In patients with rheumatoid arthritis, however, predictive accuracy of 111-indium-labeled WBC imaging was higher than with standard diagnostic methods. The difference was statistically significant (P < 0.05, chi(2)-test). In the patients examined as a whole, predictive accuracy of 111-indium-labeled WBC imaging does not differ from that of standard diagnostic methods. That is why expensive and time-consuming 111-indium-WBC imaging is not justified generally in diagnosis of infection of implants. 111-Indium-WBC imaging is well suited to supplement standard diagnostic methods in patients with rheumatoid arthritis.