Matrix-associated autologous chondrocyte transplantation in a compartmentalized early stage of osteoarthritis.

OBJECTIVE: Cartilage restoration in joints with an early stage of osteoarthritis (OA) is an important clinical challenge. In this study, a compartmentalized, early-stage OA was generated surgically in sheep stifle joints, and this model was used to evaluate a matrix-associated cell transplantation approach for cartilage repair. METHOD: Eighteen sheep were operated twice. During the first operation, a unicompartmental OA in a stable joint was induced by creating a critical-size defect. The second operation served as a regeneration procedure. The eighteen sheep were divided into three groups. One group was treated with spongialization (SPONGIO), while the two others had spongialization followed by implantation of a hyaluronan matrix with (MACT) or without chondrocytes (MATRIX). The follow-up took place 4 months after the second operation. Gross Assessment of Joint Changes score and Brittberg score were used for the macroscopic evaluation, Mankin score, O'Driscoll score, and immunohistochemistry for collagen type I and type II for histological evaluation. RESULTS: The MACT group achieved significantly better results in both macroscopic and histological examinations. In the regeneration area, a Mankin score of 7.88 (6.20; 9.55) [mean (upper 95% confidence interval; lower 95% confidence interval)] was reached in the MACT group, 10.38 (8.03; 12.72) in the MATRIX group, and 10.33 (8.80; 11.87) in the SPONGIO group. The O'Driscoll score revealed a highly significant difference in the degree of defect repair: 15.92 (14.58; 17.25) for the MACT group compared to the two other groups [5.04 (1.21; 8.87) MATRIX and 6.58 (5.17; 8.00) SPONGIO; P < 0.0001]. CONCLUSION: This study demonstrates promising results toward the development of a biological regeneration technique for early-stage OA.

Microfracture in the Ankle: Clinical Results and MRI with T2-Mapping at 3.0 T after 1 to 8 Years.

BACKGROUND: Microfracture (MFX) is frequently used to treat deep cartilage defects in the ankle; however, the data on repair tissue (RT) quality after MFX are very limited at this time. T2-mapping at 3 T has been optimized for the ankle and can be used to noninvasively evaluate cartilage collagen and water content. The aim of this study was to determine if the RT after MFX in the ankle had T2 properties similar to the adjacent reference cartilage (RC). METHODS: Fourteen cases after MFX in the ankle were assessed with morphological MRI and T2-mapping at 3 T. The American Orthopaedic Foot and Ankle Society (AOFAS) score and a modified Cinicinnati Knee Rating System rating were used to evaluate the clinical outcome. The MRI protocol included a 3-dimensional sequence and a proton-density sequence for morphological evaluation and a multiecho spin echo sequence for T2-mapping. Region of interest analyses were carried out in accordance with the morphological images to ensure complete coverage of the defect site. RESULTS: Both clinical scores demonstrated significant improvement at the time of the MR examination (P < 0.001). RT T2 was 49.3 ± 10.1 (range, 35.7-69.3) milliseconds, and RC T2 was 49.9 ± 8.2 (range, 38.4-63.7) milliseconds (P = 0.838). Relative T2 (rT2) was 1.00 ± 0.20 (range, 0.72-1.36). CONCLUSION: MFX in the ankle can provide RT with T2 properties similar to adjacent cartilage.

T2 mapping and dGEMRIC after autologous chondrocyte implantation with a fibrin-based scaffold in the knee: preliminary results.

OBJECTIVE: To assess repair tissue (RT) after the implantation of BioCartII, an autologous chondrocyte implantation (ACI) technique with a fibrin-hyaluronan polymer as scaffold. T2 mapping and delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) were used to gain first data on the biochemical properties of BioCartII RT in vivo. METHODS: T2 mapping and dGEMRIC were performed at 3T in five patients (six knee joints) who had undergone ACI 15-27 months before. T2 maps were obtained using a pixel wise, mono-exponential non-negative least squares fit analysis. For quantitative T1 mapping a dual flip angle 3D GRE sequence was used and T1 maps were calculated pre- and post-contrast using IDL software. Subsequent region of interest analysis was carried out in comparison with morphologic MRI. RESULTS: A spatial variation of T2 values in both hyaline, normal cartilage (NC) and RT was found. Mean RT T2 values and mean NC T2 values did not differ significantly. Relative T2 values were calculated from global RT and NC T2 and showed a small range (0.84-1.07). The relative delta relaxation rates (rDeltaR1) obtained from the T1 maps had a wider range (0.77-4.91). CONCLUSION: T2 mapping and dGEMRIC provided complementary information on the biochemical properties of the repair tissue. BioCartII apparently can provide RT similar to hyaline articular cartilage and may become a less-invasive alternative to ACI with a periosteal flap.

[Introduction to methods of economic modelling: a primer for orthopaedic surgeons and traumatologists]. / Eine Einführung in Methoden der ökonomischen. Evaluation für Orthopäden und Unfallchirurgen.

AIM: Health economics and cost-efficiency are ubiquitously present issues in present day orthopaedic surgery. These subjects, however, are almost exclusively dealt with by economists and policy makers, while medical professionals rarely take part, quite often because of insufficient methodological knowledge. This report presents the basics of economic evaluation to orthopaedic surgeons to facilitate informed discussion. METHOD: This text reviews the basic methodology of economic evaluation and pertinent findings for orthopaedic surgery. RESULTS: Economic evaluation combines costs and consequences of medical treatments. Partial analyses study costs only, while complete studies include different parameters of consequence. Cost-effectiveness analysis sets cost and effectiveness in natural metrics in relation, while cost-utility analyses present consequences as quality-adjusted life years. Cost-benefit analyses translate both costs and consequences into money value and thus produce a net benefit. Orthopaedic research focuses mainly on cost-utility analyses, yet their number and quality, despite both have been rising over the last years, are mostly insufficient to come to unequivocal conclusions or to produce clear recommendations. CONCLUSION: The trend for an increasing demand for economic evaluations in orthopaedic surgery will continue unabated. Both patients and medical professionals would benefit if orthopaedic surgeons received instruction in economic evaluations in order to be able to take part in such studies or to meaningfully discuss such matters.

[Outcomes after minimally invasive total knee replacement--a meta-analysis]. / Ergebnisse nach minimalinvasivem Knieersatz - eine Metaanalyse.

AIM: A systematic review of randomised controlled trials reporting on the comparison of minimally invasive total knee replacement and standard incision technique was carried out. METHOD: Online searches were performed in Medline, CINAHL, EMBASE, and the Cochrane Controlled Trials Register. Data concerning the endpoints postoperative pain, function, complications, and implant position were extracted in duplicate and pooled using fixed and random effects models. RESULTS: Weighted mean differences for postoperative pain showed 1.4 (95 % CI 1.8 to 1.0, p = 0.014) point better results for MIS. For function, standardised mean differences were calculated and showed better results for MIS, too (0.6 points, 95 % CI 0.03 to 1.12, p = 0.038). There were no significant differences in complication rates (OR 1.3, 95 % CI 0.6 to 2.9, p = 0.477) and implant position. Meta-regression showed no influence of navigation on any of the endpoints. CONCLUSION: Minimally invasive total knee replacement showed better postoperative pain and function without any differences in complication rates or implant position.

[Clinical applicability of evidence-based orthopedics--a cross-sectional study of the quality of orthopedic evidence]. / Die klinische Anwendbarkeit evidenzbasierter Orthopädie--Eine Querschnittsstudie der Qualität der Evidenz orthopädischer Studien.

INTRODUCTION: The demand to routinely apply evidence-based methods in orthopedic surgery increases steadily. In order to do so, however, the validity and reliability of the "evidence" has to be scrutinized. AIM: The object of this study was to assess the quality of the most recent orthopedic evidence and to determine variables that have an influence on quality. METHOD: All 2006 controlled trials from orthopedic journals with high impact factors were analysed in a cross-sectional study. A score based on the CONSORT statement was used to assess study quality. Selected variables were tested for their influence on the quality of the study. RESULTS: Two independent blinded observers reviewed 126 studies. The overall quality was moderate to high. The most neglected parameters were power analysis, intention-to-treat, and concealment. The participation of a methodologically trained investigator increases study quality significantly. There was no difference in study quality irrespective of whether or not there was statistically significant result. CONCLUSION: Using our quality score we were able show fairly good results for recent orthopedic studies. The most frequently neglected issues in orthopedic research are blinding, power analysis, and intention-to-treat. This may distort the results of clinical investigations considerably and, especially, lack of concealment causes false-positive findings. Our data show furthermore that participation of a methodologist significantly increases quality of the study and consequently strengthens the reliability of results.

[Tissue engineering in orthopaedic surgery--clinical effectiveness and cost effectiveness of autologous chondrocyte transplantation]. / Tissue Engineering in der Orthopädischen Chirurgie--Klinischer Effekt und Kosten-Nutzen-Analyse der autologen Chondrozytentransplantation im Kurz- und Langzeitmodell.

BACKGROUND: Tissue engineering applications are spreading in orthopaedic surgery. The best known example is autologous chondrocyte transplantation (ACT). The objective of this work is to compare ACT with alternative treatment options concerning long-term effects and cost-effectiveness. MATERIAL AND METHODS: Data on clinical effectiveness, long-term effects, and cost-effectiveness are systematically reviewed. Due to the high clinical and statistical heterogeneity between studies a descriptive analysis has been done. RESULTS: 6 randomised controlled studies have assessed the effectiveness of ACT compared with microfrature or mosaic plasty. 4 studies report on no or only insignificant differences - one recently presented 5-year results - whereas 2 studies observed better results with ACT. Long-term results are good throughout, but the high quality of the regenerative tissue is a clear advantage of ACT. Cost-effectiveness models support ACT for the longevity of its results and thus relatively lower costs in the long-term. CONCLUSION: ACT is an expensive and complex procedure. In direct comparison with alternative treatments ACT produces results at least as good in the short-term, and most likely better in the long-term due to the high quality repair tissue. Thus higher initial costs are compensated for with time.

T2 mapping in the knee after microfracture at 3.0 T: correlation of global T2 values and clinical outcome - preliminary results.

OBJECTIVE: The aim of our study was to correlate global T2 values of microfracture repair tissue (RT) with clinical outcome in the knee joint. METHODS: We assessed 24 patients treated with microfracture in the knee joint. Magnetic resonance (MR) examinations were performed on a 3T MR unit, T2 relaxation times were obtained with a multi-echo spin-echo technique. T2 maps were obtained using a pixel wise, mono-exponential non-negative least squares fit analysis. Slices covering the cartilage RT were selected and region of interest analysis was done. An individual T2 index was calculated with global mean T2 of the RT and global mean T2 of normal, hyaline cartilage. The Lysholm score and the International Knee Documentation Committee (IKDC) knee evaluation forms were used for the assessment of clinical outcome. Bivariate correlation analysis and a paired, two tailed t test were used for statistics. RESULTS: Global T2 values of the RT [mean 49.8ms, standards deviation (SD) 7.5] differed significantly (P<0.001) from global T2 values of normal, hyaline cartilage (mean 58.5ms, SD 7.0). The T2 index ranged from 61.3 to 101.5. We found the T2 index to correlate with outcome of the Lysholm score (r(s)=0.641, P<0.001) and the IKDC subjective knee evaluation form (r(s)=0.549, P=0.005), whereas there was no correlation with the IKDC knee form (r(s)=-0.284, P=0.179). CONCLUSION: These findings indicate that T2 mapping is sensitive to assess RT function and provides additional information to morphologic MRI in the monitoring of microfracture.

[Minimally invasive hip replacement--a meta-analysis]. / Der minimalinvasive Hüftersatz - eine Metaanalyse.

AIM: A systematic review of randomized controlled trials reporting on the comparison of minimally invasive THA and standard incision technique. METHOD: An online search in Medline, CINAHL,EMBASE, and the Cochrane Controlled Trials Register was performed. Data concerning the endpoints duration of procedure, blood loss,complications, and Harris Hip Score (HHS) were extracted and pooled using a random effects model. RESULTS: 8 Studies observing a total of 917 patients(481 MIS, 436 Std.) were included. The weighted mean difference in duration of the procedures was 4 min, which is not significant(p = 0.21). There was significantly less blood loss in the mini group (p < 0.001). The difference in increases in HHS of averagely 4.14 pts. was only borderline significant (p = 0.06). The complication odds ratio showed no significance (p = 0.71). CONCLUSION: There is only a marginal difference between these techniques. The minimally invasive total hip replacement is a variance of the standard procedure with better cosmesis. Differences in postoperative rehabilitation, however,are not within the scope of this study.

A tissue engineering approach to meniscus regeneration in a sheep model.

OBJECTIVE: Regeneration of the meniscal tissue occurs to a limited extent, and the loss of meniscal tissue leads to osteoarthritis. A new biomaterial consisting of hyaluronic acid and polycaprolactone was used as a meniscus substitute in sheep to evaluate the properties of the implant material with regard to size, biomechanical stability, tissue ingrowth, and integration. METHODS: Eight sheep (right stifle joints) were treated with three total and three partial meniscus replacements while two meniscectomies served as empty controls. The animals were euthanized after 6 weeks. The specimens were assessed by gross inspection and histology, and compared with the nonoperated left joints. RESULTS: The surgical technique was found to be feasible. The implants remained in position, did not tear, and showed excellent tissue ingrowth to the capsule. Tissue integration was also observed between the original meniscus and the implant. However, graft compression and extrusion occurred. The histological investigation revealed tissue formation, cellular infiltration and vascularization. Cartilage degeneration was more severe in the operated joints. CONCLUSION: The present study shows promising results concerning the qualities of this biomaterial with regard to implantation technique, stability and tissue ingrowth.

Three-year clinical outcome after chondrocyte transplantation using a hyaluronan matrix for cartilage repair.

Repair of articular cartilage represents a significant clinical problem and although various new techniques - including the use of autologous chondrocytes - have been developed within the last century the clinical efficacy of these procedures is still discussed controversially. Although autologous chondrocyte transplantation (ACT) has been widely used with success, it has several inherent limitations, including its invasive nature and problems related to the use of the periosteal flap. To overcome these problems autologous chondrocytes transplantation combined with the use of biodegradable scaffolds has received wide attention. Among these, a hyaluronan-based scaffold has been found useful for inducing hyaline cartilage regeneration. In the present study, we have investigated the mid-term efficacy and safety of Hyalograft C grafts in a group of 36 patients undergoing surgery for chronic cartilage lesions of the knee. Clinical Outcome was assessed prospectively before and at 12, 24, and 36 months after surgery. No major adverse events have been reported during the 3-year follow-up. Significant improvements of the evaluated scores were observed (P < 0.02) at 1 year and a continued increase of clinical performance was evident at 2 and 3 years follow-up. Patients under 30 years of age with single lesions showed statistically significant improvements at all follow-up visits compared to those over 30 with multiple defects (P < 0.01). Hyalograft C compares favorably with classic ACT and is particularly indicated in younger patients with single lesions. The graft can be implanted through a miniarthrotomy and needs no additional fixation with sutures except optional fibrin gluing at the defect borders. These results suggest that Hyalograft C is a valid alternative to ACT.

Marrow stimulation and chondrocyte transplantation using a collagen matrix for cartilage repair.

OBJECTIVE: The purpose of the study was to determine whether the implantation of a scaffold would facilitate cartilage repair after microfracture in sheep over a period of 12 months. Furthermore, we investigated the effect of additional autologous cell augmentation of the implanted constructs. METHODS: Two chondral defects were produced in the medial femoral condyle of sheep without penetrating the subchondral bone. Twenty-seven sheep were divided into the following groups: seven served as untreated controls (Group 1), microfracture was created in 20 animals, seven of them without further treatment (Group 2), in six sheep the defects were additionally covered with a porcine collagen matrix (Group 3), and in seven animals the matrix was augmented with cultured autologous chondrocytes (Group 4). After 4 (11 sheep) and 12 months (16 sheep), the filling of the defects, tissue types, and semiquantitative scores were determined. RESULTS: The untreated defects revealed the least amount of defect fill. Defects treated with microfractures achieved better defect fill, while the additional use of the matrix did not increase the defect fill. The largest quantity of reparative tissue was found in the cell-augmented group. Semiquantitative scores were best in the cell-augmented group. CONCLUSION: Microfracture treatment was observed to enhance the healing response. The implantation of a cell-seeded matrix further improved the outcome. The implantation of a collagen matrix alone did not enhance repair. Autologous cell implantation appears to be a very important aspect of the tissue engineering approach to cartilage defects.

Repair of articular cartilage defects treated by microfracture and a three-dimensional collagen matrix.

The objective of our study was to evaluate the behavior of ovine chondrocytes and bone marrow stromal cells (BMSC) on a matrix comprising type-I, -II, and -III collagen in vitro, and the healing of chondral defects in an ovine model treated with the matrix, either unseeded or seeded with autologous chondrocytes, combined with microfracture treatment. For in vitro investigation, ovine chondrocytes and BMSC were seeded on the matrix and cultured at different time points. Histological analysis, immunohistochemistry, biochemical assays for glycosaminoglycans, and real-time quantitative PCR for collagens were performed. The animal study described here included 22 chondral defects in 11 sheep, divided into four treatment groups. Group A: microfracture and collagen matrix seeded with chondrocytes; B: microfracture and unseeded matrices; C: microfracture; D: untreated defects. All animals were sacrificed 16 weeks after implantation, and a histomorphometrical and qualitative evaluation of the defects was performed. The in vitro investigation revealed viable cells up to 3 weeks; chondrocytes had a predominantly round morphology, produced glycosaminoglycans, and expressed both collagen markers, whereas BMSC stained positive for antibodies against type-II collagen; however, no mRNA for type-II collagen was amplified. All treatment groups of the animal model showed better defect filling compared to untreated knees. The cell-seeded group had the greatest quantity of repair tissue and the largest quantity of hyaline-like tissue. Although the collagen matrix is an adequate environment for BMSC in vitro, the additionally implanted unseeded collagen matrix did not increase the repair response after microfracture in chondral defects. Only the matrices seeded with autologous cells in combination with microfracture were able to facilitate the regeneration of hyaline-like cartilage.

[Mid-term results of autologous chondrocyte transplantation in knee and ankle. A one- to six-year follow-up study]. / Mittelfristige Ergebnisse mit der autologen Knorpelzelltransplantation an Knie- und SprunggelenkEin- bis Sechsjahresergebnisse.

BACKGROUND: The reimplantation of autologous chondrocytes is a new technique in reconstruction of cartilage defects; initial results achieved with this technique have been promising. In an arthroscopic procedure, scales of cartilage are obtained from intact cartilage. The chondrocytes are then multiplied in special laboratories. A few weeks later, in a second procedure, the cartilage defect is filled with the cell suspension and closed with a flap of periosteum. METHOD: At our department, autologous chondrocyte transplantation (ACT) has been used in 10 patients since 1996, in 6 cases in the knee joint, and in 4 cases in the ankle joint. The mean age of the patients was 30 years. The mean size of the defect was 4 cm(2). In 4 patients, a parallel surgical procedure was required at the time of removal. RESULTS: The mean duration of follow-up was 21/2 years. Six patients had good to excellent results, 3 patients had moderate results, and one patient a poor result. The modified Cincinnati rating scale was improved from 2.4 to 7.1 points, and the Lysholm score from 59.2 to 86.6 points. The AOFAS score for ankle joints had improved from 33 to 76. CONCLUSION: We were able to show that ACT achieves improvement in the knee as well as ankle joint in the majority of patients. ACT appears to be a promising therapeutic concept for both joints.

The influence of immediate surgical treatment of proximal femoral fractures on mortality and quality of life. Operation within six hours of the fracture versus later than six hours.

We compared the mortality and outcome of 182 patients with proximal fractures of the femur after immediate and delayed surgical treatment. Seventy-nine patients were operated upon within six hours of the fracture (group 1) and 103 patients were operated upon after this period of time (group 2). At six months follow-up, group 1 had a significantly lower mortality rate. There was a good outcome in both groups with no differences in the outcome. Neither surgical nor anaesthetic factors appeared to have influenced mortality. The subdivision of groups revealed that patients operated on within 24 hours had a better outcome than those whose surgery was delayed. Although there may have been a bias, as patients were not randomly assigned to immediate or delayed surgical treatment, the data suggest that early stabilisation may be associated with a lower mortality rate. Even with pre-clinical delays of more than six hours early treatment should still be attempted, as better results seem to be achieved after 24 hours compared to a later time in our patients.

Effects of extracorporeal shock waves on human articular chondrocytes and ovine bone marrow stromal cells in vitro.

INTRODUCTION: We investigated the effects of extracorporeal shock waves on cytotoxicity and on the proliferation of human chondrocytes and ovine bone marrow stromal cells. MATERIALS AND METHODS: Isolated cells were cultured to confluence, and 500 shock waves were applied at energy flux densities of 0, 0.02, 0.06, and 0.17 mJ/mm(2 )for the cytotoxicity assay. The same energies at 100, 500, and 1000 impulses were used for the proliferation assay. RESULTS: Although bone marrow stromal cells revealed a dose- and impulse-dependent increase in the proliferation rate, no significant differences were found. Chondrocytes had less proliferative potential than untreated control groups. In the experimental set-up using 1000 impulses, proliferation was even higher in the control group. Both types of cells revealed a dose-dependent increase in cytotoxicity in the lactate dehydrogenase (LDH) assay. CONCLUSION: As femoral head necrosis, osteochondritis dissecans, and similar disorders are increasingly treated with shock waves, their effect on human cartilage and chondrocytes deserves attention. We recommend further in vitro experiments with bone marrow stromal cells, as the latter might play an important role in the presumed multifactorial osteogenetic mechanism of shock waves due to their pluripotent character.

[Influence of nocturnal surgery on mortality and complications in patients with hip fractures]. / Auswirkungen von in der Nacht durchgeführten Stabilisierungsoperationen bei hüftnahen Femurfrakturen auf Mortalitätsrate und Komplikationen.

UNLABELLED: SUBJECT OF INVESTIGATION: The appropriate time of day for surgery of hip fractures and the question of whether surgery should be performed at night are controversial. We therefore investigated the influence of the time of day on mortality and complication rates in surgery for hip fractures. METHOD: A total of 170 persons were included in the study with 128 operations being performed during the day and 42 at night, after 9 p.m. All patients were operated as early as possible. Patients were randomly assigned to groups. The recorded data were mainly demographic, perioperative and those concerning the patient's history. Mortality and complication rates 6 months after surgery were compared. RESULTS: The two groups were largely homogeneous. Patients operated on at night had a non-significantly higher mortality rate. Mortality was highest in those operated on between 9 and 10 p.m. Of those who underwent surgery after midnight, no patient died. No differences were registered with regard to complications. The team of surgeons and anesthetists was equally qualified in both groups. CONCLUSIONS: Given a medical team with equal qualifications and size, we consider nocturnal surgery for hip fractures to be as appropriate as surgery during the day.

[3D-navigated high energy shockwave therapy and axis correction after failed distraction treatment of congenital tibial pseudarthrosis]. / 3D-navigierte hochenergetische Stosswellentherapie und Achskorrektur nach fehlgeschlagener Distraktionsbehandlung bei kongenitaler Tibiapseudarthrose.

The treatment of congenital tibial pseudarthrosis using a distraction procedure as described by Ilizarov is a standard surgical intervention. Nevertheless, there are problems in achieving bony stability in about 10% of cases even after repeated surgery as reported by Lammens et al. (2000). Traub et al. (1999) found a rate of 50% amputations in 33 cases treated since 1927. To prevent an Ilizarov procedure from resulting in a delayed union or nonunion, Paley et al. (1992) recommended autografting immediately after distraction. Based on the good results in the stimulation of osteogenesis in adults, we started to treat delayed bone union following distraction treatment with high-energy shock wave therapy also in children. In patients suffering from congenital tibial pseudarthrosis with a deviation of the bony axis, we combine this surgery-substituting therapy with fixation of a Taylor spatial frame in order to correct the axis. Using this new method of treatment, we were able to achieve stability in four children who previously had had nonunion even after multiple surgical interventions.

[Patellofemoral pain syndrome in young men compared to a normal population exposed to the same physical strain]. / Das patellare Schmerzsyndrom bei jungen männlichen Patienten im Vergleich zu einem symptomlosen Kollektiv bei gleicher körperlicher Beanspruchung.

AIM: The causes of the patellofemoral pain syndrome, especially in young patients, continue to be largely unknown. The purpose of the study was to determine the extent to which weight and activities that impose a strain on the knee influence the occurrence of patellofemoral pain in young, physically active men. METHOD: 248 soldiers on mandatory military service were included in the study. 133 persons had pain in the knee prior to or during military service while 115 persons had no symptoms in the knee. Anthropometric data and patient history were recorded for all individuals. This was followed by clinical examination. RESULTS: Age distribution and body mass index were identical in both groups. However, significantly more subjects in the group with pain prior to military service had been active sportsmen while a significantly larger number of normal individuals had had jobs that strained the knees. The greatest difference, however, was seen in the number of previous injuries. These were much more common in the group that had pain and the injuries most commonly were contusions. CONCLUSION: It is well known that previous injuries and sports favor the emergence of patellar pain. However, persistent strain on the knee at work appears to be less commonly associated with this symptom. The individual's body-mass index was of no importance in this context.

[Periprosthetic femoral fractures in total hip prosthesis implantation. Functional and radiological comparison between plate osteosynthesis and proximal femur replacement]. / Periprothetische Femurfrakturen bei Hüfttotalendoprothesen. Funktioneller und radiologischer Vergleich zwischen Plattenosteosynthese und proximalem Femurersatz.

AIM: Clinical and radiological examinations were performed to compare plate osteosynthesis (group 1) with replacement of the proximal femur by tumor prosthesis (group 2) in patients with ipsilateral femoral fractures around a hip prosthesis. METHOD: Of 24 consecutive patients with 25 fractures, nine had died and one could be contacted by telephone leaving 14 hips (in one case only recent X-rays were available) for final review (nine patients from group 1; five from group 2). RESULTS: At the time of examination four patients of group 1 were using one cane or were walking without any support, all patients of group 2 needed one or two crutches. In 5 of 9 patients in group 1 and in 4 of 5 in group 2 a firm fit of the prosthesis was observed. CONCLUSION: Group 1 achieved better clinical results in postoperative mobility, whereas femoral replacement showed better radiological results. Survival of patients with tumor prostheses was considerably superior to that of patients with plate osteosynthesis.