Mechanical resistance of biological repair cartilage: comparative in vivo tests of different surgical repair procedures.

The former common knowledge that cartilage lesions do not heal has been modified over the last few years due to new technologies. For repair of deeper circumscribed lesions osteochondral press-fit grafting and tissue engineering are used in clinical application. The histological data of the hyaline-like tissue obtained by engineering are just as satisfactory as the surviving grafted hyaline cartilage on top of osteochondral cylinders. But comparative studies are still lacking. To fill the gap and with a view to repairing larger osteoarthritic defects we have performed an in vivo study on 16 goats. Three months after the creation of a full thickness wide cartilage defect on the femoral condyle with harvesting of cartilage samples for tissue cultures we performed secondary cartilage repair procedures on the installed osteoarthritis areas: 1) grafting with autogenic osteochondral press-fit cylinders from the opposite knee, 2) autologous engineered chondrocyte grafting under periosteal flaps, 3) both in combination. The harvesting defects were either left as controls or filled with a hyaluronate fleece. After eight months the repaired areas and the harvesting defects were examined for cartilage stiffness as a novel comparative parameter. Compared to normal the cartilage on top of osteochondral grafts is considerably stiffer. Engineered cartilage is weaker than normal. Spontaneously ingrown fibrous cartilage is much weaker even with a carrier fleece. A combination of osteochondral press-fit grafts with engineered autologous cells restores biomechanical qualities to repaired larger degenerative cartilage defects.

[Shift and tilt of the bony patella in total knee replacement]. / Shift und Tilt der ossären Patella in der Knietotalprothese.

Resurfacing the patella or not in total knee arthroplasty is generally still a quite controversial topic. In that context we felt a necessity to get more informations about the natural history of a non resurfaced patella in the prosthetic surrounding than only in comparison with a replaced patella. By the fact that we haven't been replacing patellae apart from special cases since up to five years, we have available a patient selection on which this question can be studied. Thirty primary total knee replacements with documented 2 year's follow up have been investigated by calculation of the radiological patellar shift and tilt relative to the natural groove on preoperative X-rays and to the prosthetic groove in the postoperative evolution. These results were matched with the range of motion obtained after two years and with persisting pain. Only mobile polyethylene inlays had been used. With regard to the patella no difference was found for one single complete tibial tray or two separately implanted unicompartimental tibial trays. As a rule an adaptation of the bony patellar contour to the prosthetic groove was observed with an increased density of the bony contact area with or without a fibrous interstitial layer. Based on their clinical follow up examination seven patients had to be adjointed to a "residual problem group", as they presented persisting pain (3) or a poor range of motion of 90/0/0 degree of flexion/extension or less. Only in this group we found cases with a postoperative shift over 5 mm (2) and a postoperative tilt over 15 degrees (3). Inside this group, also with a significant difference from the group without residual problems, there was furthermore a correlation between persisting pain and an important preoperative tilt and between a diminished range of motion and a considerable preoperative shift. It has to be pointed out that even the cases without long severe malposition before the arthroplasty but with unsatisfactory realignement referring to the patellar tilt (7 degrees-15 degrees) have been found pain free at the last follow up. One patient with a severe secondary increase of disalignment (16 mm/139 degrees) due to an aseptic tibial loosening represents a particular case. After corrective revision of the tibial implants this patient also got again a complete pain relief and a good range of motion without any surgical measure to the patella and inspite of an evident residual tilt. Thus we have to conclude that it is justified to take important pains with the realignment to obtain a residual patellar shift of less than 5 mm. Apart from usual operative steps during the implantation to favour a good patellar tracking, e.g. a high quadriceps release or a medially transposed refixation of the detached tibial tubercle can get necessary. On the other hand a residual tilt up to 15 degrees is well tolerated, as the unresurfaced patella presents an astonishing ability of adaptation to the prosthetic groove by remodelling of the bony contour and structure. Nevertheless in the included cases of severe preoperative malposition, in which we didn't replace the patella because of a good intraoperative bone quality, we had to put up with an increased incidence of late problems even with normalized patellar tracking. In such cases an extended indication to a patellar resurfacing may be considered.

[Biophysical bases of the effects of holmium laser on articular cartilage and their impact on clinical application technics]. / Biophysikalische Grundlagenuntersuchungen zur Wirkung der Holmium-Laserstrahlung am Knorpelgewebe und deren Konsequenzen für die klinische Applikationstechnik.

The in vitro study presented helps to clarify the biophysical mechanisms and tissue interactions of the holmium laser at the point of impact on the surface of cartilage-bone specimens investigated in different experimental settings. A striking event is the creation of a vapor bubble that opens up access for the laser beam through the fluid medium. This bubble shows a reproducible dynamic behavior function of the laser irradiance and the angle of incidence of the delivery fiber. These determine directly the amplitude of the pressure waves induced when the bubble collapses. Apart from this acoustic effect, which is correlated with epicentric histological features that can hardly be considered biologically relevant, a thermal effect is recognized that is finally responsible for the ablation and tissue damage. It induces typical histological alterations that can be observed along the laser beam axis, with a penetration function mainly of the irradiance but also of the angle of incidence. Nevertheless, at a pulse energy of 1 J and an irradiation angle of 30 degrees, the recorded overall depth of the immediate histological changes was down to 500-600 micrometers. Thus, in realistic working conditions, the damage observed after cartilage sealing with the holmium laser remains within an absolutely acceptable range. This is in agreement with the better results compared to mechanical cartilage debridement that have been reported in previous prospective clinical studies.

[Open laser surgery on the locomotor apparatus]. / Offene Laserchirurgie am Bewegungsapparat.

The first applications of laser in surgery of the locomotor apparatus in the early 1980s used the haemostatic properties of laser to diminish the amount of substitution of coagulation factors in haemophiliac patients. Only since the early 1990s has a device been available in corporating the pulsed holmium:YAG laser which works in a fluid medium without relevant side effects. Apart from haemostasis, the cutting function and tissue ablation, together with the thermal shrinking effect, are exploited in arthroscopy and percutaneous disc decompression. Now that the biophysical mechanisms of action have been elucidated, nothing stands in the way of the use of infrared lasers in open surgery of the locomotor apparatus in some indications. In a prospective clinical study we included 30 consecutive patients who underwent open laser surgery from November 1992 to August 1994, for the following indications: the sparing haemostatic tissue ablation was used for synovectomy or for bony resection in osteophytes and osteochondromas of different locations, an osteoid osteoma and a painful sacral hyperplasia in the presence of incomplete sacral meningomyelocele. With bleeding eliminated, the shaping was much easier. The non-ablative shrinking produced less tissue loss and a stabilizing strengthening of tissue at the margins of soft tissue resections, e.g. in jumper's knee, tennis elbow and Achilles tendon cysts. All laser functions that are useful in open surgery have also been used in sequestered disc herniations that are inaccessible a percutaneous procedure and, in spinal decompression, for remodelling of the posterior spine contour. An analgesic effect of laser limited the postoperative administration of analgesic drugs to an average of 3 days. No complications related to the laser treatment were observed. At follow-up 12-21 months after operation, 25 of the 30 patients in this heterogeneous population showed complete or near-total healing of the operated pathological finding, and a further 3 patients showed significant improvement. To what extent these very encouraging results will persist will be shown by long-term observation.

[Use of laser in arthroscopy of the ankle. Indications, method, first results]. / Laseranwendung in der Arthroskopie des oberen Sprunggelenks. Indikationen, Technik, erste Ergebnisse.

As in the knee joint, lasers can be used during ankle arthroscopy for their resective and ablative properties. Reports on arthroscopic treatment of degenerative and post-traumatic disorder of the ankle by conventional techniques are encouraging. We have used laser in ankle arthroscopy in three main situations: (1) When exuberant scar tissue from previous capsulo-ligamentous damage (e.g. after ankle sprain) symptomatically restricts range of motion and causes pain (ankle impingement). Laser is used in this case at middle energy, as a resector. (2) In the presence of cartilaginous lesions, as in osteoarthritis, flake fractures or osteoarthritis, flake fractures or osteochondrosis dissecans. Here laser is used at lower energy to reshape the cartilaginous surface without resective effect ("welding"). (3) When impaired range of motion is due to osteophytic rims, mainly at the anterior tibia, resulting from previous capsular lesions. Laser is then used at high energy to cut excessive bone. A series of 16 patients underwent ankle arthroscopy at our clinic, mainly for post-traumatic disorders, including impingement, osteochondrosis dissecans and osteoarthritis. The most frequently encountered intraarticular findings were impingement by post-traumatic synovitis and scar tissue of the anterio-lateral and postero-lateral compartments, with or without an osteophytic rim of the distal anterior tibial border. Scar tissue, synovitis and osteophytes were debrided in half of the patients purely mechanically (with arthroscopic scissors or shaver) and in the other half with the holmium laser. The results are encouraging; 50% of patients had no symptoms at all at follow-up (9.5 months on average), and another 38% were satisfied with a significant improvement. In two cases, no improvement at all occurred: one patient complained of persistent pain with lack of objective findings and is believed to have developed "insurance neurosis." The other had severe postinfectious osteoarthritis that was operated too late in the course to influence pain positively. Concerning the clinical, functional and subjective follow-up results there was no relevant difference between the two groups. We recommend ankle arthroscopy to treat post-traumatic impingement syndromes of the antero-lateral, antero-medial and postero-lateral compartments of the ankle joint; the use of lasers seems to have a slightly better analgetic effect, allows an easier approach than is the case with shavers or other bulky arthroscopic resectors, and allows shaping of convex resection surfaces, which cannot be performed with a shaver.

Adenomyosis--an unusual cause of sciatic pain.

We report the case of a female patient who presented with a 5-month history of sciatic pain. She was referred to us for investigation and eventual surgical treatment of a suspected herniated lumbar intervertebral disc. Because of an ill-defined clinical picture at admission, she was treated conservatively. After 2 weeks without any improvement, imaging of the spine by MR was performed. No signs of a herniated disc or intraspinal, space-occupying lesion were apparent, but a right paramedian pelvic mass was seen. Ultrasonography confirmed an enlarged, irregular uterus. Hysterectomy abolished the symptoms.

Patterns of cigarette, alcohol, and other drug use among children and adolescents: a longitudinal study.

Findings are presented from an 18-month longitudinal study of substance use behavior among 400 children and adolescents, ages 9-17 at the first interviews. Patterns of use from two sequential interviews are reported. Descriptive results are presented as simple frequencies and cross-tabulated with demographic items (age, sex, ethnicity, and socio-economic status). Patterns of use over an 18-month period are examined for cigarettes, alcohol, marijuana/hashish, and other drugs. Four patterns are assessed for each of these substances--abstention at both the first and second interviews; abstention at the first, but not the second interview; use at the first interview, abstention at the second; and use at both interviews.

Patterns of substance use among children and youth: a longitudinal study.

This report presents a set of findings from a three wave 36 month longitudinal study on the use of cigarettes, alcohol, marijuana/hashish and other drugs by a population of children and adolescents ranging in age from 9 to 17 at the time of first interview. Gross differences in percentages of subjects reporting using substances across the three data collection intervals are found to be quite small. However, when these differences are examined in detail, it is found that a good deal of initiation of use by some subjects and curtailing of use by others stands behind the relatively small net changes in use from one interval to another. Escalation in substance use, from less mood altering to more mood altering substances, is found to exist, but to appear far less frequently than "initial" multiple drug use. Finally, "intensity" of use of one substance is found to be somewhat related to age and very strongly related to the use of other substances. Limitations of findings due to episodic rather than continuous monitoring of substance use are noted.