[Radial MRI of the hip joint for evaluation of degenerative changes in the young adult: a comparison of different sequences]. / Radiäre MRT des Hüftgelenks zur Abklärung präarthrotischer Veränderungen im jungen Erwachsenenalter: ein Vergleich verschiedener Sequenzen.

AIM: Femoroacetabular impingement has been shown to be an important cause for the development of osteoarthritis of the hip joint. Radial MRI of the hip has proven to be the diagnostic procedure of choice to differentiate which patient to operate. While examinations after instillation of contrast agents have been described, new papers have shown high accuracy without contrast medium. Since instillation of contrast medium is considered painful and poses the risk of infection, it is not performed for MRI evaluation of the hip at our institution. However, the question as to which sequence to use has not been settled yet. Therefore, four frequently used sequences using the same resolution were compared. MATERIALS AND METHODS: A retrospective analysis of T (1)-weighted (T (1)), T (2)-weighted (T (2)) and proton density sequences (the latter with and without fat saturation [PDfs and PD]) of 50 hips in 48 patients with femoro-acetabular impingement and developmental dysplasia of the hip was performed by two raters blinded to the clinical information. The different sequences were rated separately. Evaluated criteria were subjective imaging quality, power to differentiate acetabular from femoral cartilage as well as the labrum from the joint capsule, and localisation and characterisation of pathological changes in joint cartilage, the labrum and at the femoral head-neck junction. RESULTS: Subjective imaging quality was assessed to be similar for T (1), PDfs and PD, whereas it was significantly worse for T (2). In discriminating specific intraarticular structures, however, only PDfs and PD were superior. The differentiation of acetabular from femoral cartilage was possible in only 44% and 40% of T (1) and T (2) images, but in 79% and 76% of PDfs and PD images. Similar results were found for the differentiation of the acetabular labrum from its vicinity, especially the joint capsule (36%, 35%, 77% and 74%, respectively). Intralabral pathology was seen in a comparable extent in all sequences. An intramedullary oedema at the head-neck junction, however, was significantly more frequent in PDfs only (67% vs. 0%, 17% and 10% for PDfs vs. T (1), T (2) and PD). CONCLUSION: Despite their good subjective quality, T (1)- and T (2-)weighted sequences could not depict the acetabular labrum as efficiently as PD-weighted sequences. Concluding from our data, a PDfs sequence (possibly combined with a conventional PD sequence) is advantageous over T (1) and T (2) sequences. Intraarticular administration of contrast medium seems to be superfluous.

[Transfixation in slipped capital femoral epiphysis: long-term evidence for femoro-acetabular impingement]. / Transphysäre Fixation bei Epiphyseolysis capitis femoris: Hinweise für femoroazetabuläres Impingement im Langzeitverlauf.

AIM: It was the aim of this study to reveal whether and to what extent femoro-acetabular impingement (FAI) was present 10 to 20 years after transfixation of the gliding epiphysis in patients treated for unilateral slipped capital femoral epiphysis (SCFE). METHOD: Clinical and radiological evaluations were undertaken of 20 patients who were treated with a bilateral transfixation of the epiphysis with screws or Kirschner wires because of mild unilateral SCFE. The Harris hip score, the activity level according to Tegner and Lysholm and the range of motion of both hip joints were noted. An impingement provocation test was performed on both sides. The femoral head-neck junction was qualitatively and quantitatively assessed in anteroposterior radiographs of the pelvis and "cross table" lateral radiographs of both hip joints. Quantitative assessment was achieved by measuring the alpha angle according to Nötzli et al. RESULTS: All except one patient showed excellent results in the Harris hip score. The activity levels of the majority of patients, however, were mediocre. There was no difference for flexion, whereas internal rotation and abduction significantly differed between affected and non-affected hips (p = 0.135, p = 0.002 and p = 0.007, respectively). The impingement provocation test was found positive in eight affected and five non-affected hips (p = 0.004). The alpha angle was significantly different between affected and non-affected hips in the anteroposterior radiographs of the pelvis (86 vs. 61 degrees; p < 0.001), but not so, however, in the "cross table" lateral radiographs (52 vs. 46 degrees; p = 0.145). CONCLUSION: Clinical evaluation of 20 patients at a mean of 14.9 years after transfixation of the epiphysis revealed some evidence for the presence of FAI in affected hip joints. Radiological evaluation suggests that its localisation is more lateral and less anterior.

Radiological evidence of femoroacetabular impingement in mild slipped capital femoral epiphysis: a mean follow-up of 14.4 years after pinning in situ.

Conventional treatment of mild slipped capital femoral epiphysis consists of fixation in situ with wires or screws. Recent contributions to the literature suggest that even a mild slip may lead to early damage of the acetabular labrum and adjacent cartilage by abutment of a prominent femoral metaphysis. It has been suggested that the appropriate treatment in mild slipped capital femoral epiphysis should not only prevent further slipping of the epiphysis, but also address potential femoroacetabular impingement by restoring the anatomy of the proximal femur. Between October 1984 and December 1995 we treated 16 patients for unilateral mild slipped capital femoral epiphysis by fixation in situ with Kirschner wires. In this study we have reviewed these patients for clinical and radiological evidence of femoroacetabular impingement. There was little clinical indication of impingement but radiological evaluation assessing the femoral head-neck ratio and measuring the Nötzli alpha angle on the anteroposterior and cross-table radiographs showed significant alterations in the proximal femur. None of the affected hips had a normal head-neck ratio and the mean alpha angle was 86 degrees (55 degrees to 99 degrees ) and 55 degrees (40 degrees to 94 degrees ) on the anteroposterior and lateral cross-table radiographs, respectively. While our clinical data favours conventional treatment, our radiological findings are in support of restoring the anatomy of the proximal femur to avoid or delay the development of femoroacetabular impingement following mild slipped capital femoral epiphysis.

Histopathology of cryopreserved bone allo- and isografts: pretreatment with dimethyl sulfoxide.

Partial graft cell survival and enhanced graft revascularization have suggested fast freezing using the cryoprotective substance dimethyl sulfoxide (DMSO) as a promising means to improve the biologic function and immune tolerance of allograft bone. This study determines the presence of osteoblasts (cola(1)(I) mRNA), osteoclasts (TRAP), and cytotoxic T cells (CTLs; GrA mRNA) within pretreated bone grafts 12 days after transplantation. The grafts were transplanted either as isografts, allografts, or allografts in presensitized recipients. In fresh isografts, serving as control, well-formed blood vessels and the highest numbers of viable osteoblasts and osteoclasts were found. In fresh allografts, blood vessels were observed within the marrow cavity and the bone was partially covered by osteoblasts and osteoclasts accompanied by CTLs. In DMSO-pretreated frozen allografts, blood vessels together with osteoblasts were observed in three of five, but in none of five grafts frozen without DMSO. However, infiltration with CTLs was higher in DMSO-pretreated frozen allografts when compared to grafts frozen without DMSO. In presensitized allograft recipients, independent of the pretreatment, in none of the grafts were either blood vessels or osteoblasts found. Thus, fast cryopreservation of bone using DMSO improves vascularization and expression of cola(1)(I) mRNA (osteoblasts) after allografting when compared to cryopreservation alone, potentially improving graft incorporation. As these grafts were still invaded by CTLs, the long-term effect of DMSO pretreatment needs to be defined.

[Outcome assessment in total knee arthroplasty: is the clinical measurement of range of motion a reliable measurable outcome variable?]. / Outcome-Messung in der Knieendoprothetik: Ist die klinische Bestimmung der Gelenkbeweglichkeit eine zuverlässig messbare Ergebnisgrösse?

AIM: The aim of this clinical study was to investigate the reliability of the clinical assessment (visual and goniometric) of the range of motion of the knee joint. METHOD: 30 patients were assessed concerning the range of motion of their knee joints by visual and goniometric measurements. Assessment was performed by three investigators. The obtained data were used to analyse the intra- and interobserver reliability. Statistical analysis was performed using the Spearman coefficient of correlation [r (s)]. RESULTS: Intraobserver agreement was consistent across observers regarding the visual and goniometric assessment of flexion (r (s) > 0.6), whereas reliability was uniformly low for both measurements regarding the assessment of extension (r (s) < 0.6). Interobserver agreement was consistent across all three goniometric and two out of three visual assessments regarding the measurement of flexion (r (s) > 0.6); the interobserver reproducibility of extension, however, was uniformly low both for the visual and goniometric measurements (r (s) < 0.6). CONCLUSION: Reliability of clinical assessment of range of motion should be taken critically into consideration whilst performing classical function-related scoring systems when measuring outcome after total joint arthroplasty, since these scoring systems are strongly based on a valid and reliable assessment of range of motion.

[Reliability of transcutaneous measurement of oxygen tension on the lower leg]. / Reliabilität der transkutanen Sauerstoffpartialdruckmessung an der unteren Extremität.

AIM: Measurement of transcutaneous oxygen tension is increasingly used to determine the appropriate level of amputation in patients with vascular disease. The purpose of the present study was to analyze the intra- and interrater reliability of transcutaneous oxygen [tcpO (2)] measurements in a homogeneous study group. METHOD: Five investigators assessed the transcutaneous oxygen tension of both lower legs of seven persons in a fixed setting. Assessment was repeated with the same examiners and the same examinees after 24 hours. TcpO (2) was measured at the posterior aspect of the lower leg twenty centimeters below the knee joint line. The TCM 400 Monitoring System (Radiometer Medical AIS, Bronshoj, Denmark) was used. Statistical analysis of the intra- and interrater reliability was performed with the Spearman coefficient of correlation. RESULTS: An overall mean of 56.2 +/- 10.6 mmHg was found. For the first examination, a mean of 55.3 +/- 10.6 mmHg was observed, whereas for the second examination it was 57.0 +/- 10.5 mmHg. Analysis of intrarater reliability showed a coefficient of correlation of r (s) = 0.56 (p < 0.0001). For interrater reliability, we found coefficients of correlation ranging from r (s) = 0.20 (p = 0.20) to r (s) = 0.69 (p = 0.0004). CONCLUSION: Analysis of transcutaneous oxygen tension measurements performed by different investigators in a fixed setting revealed a non- homogeneous intra- and interrater reliability, which should be taken into account prior to initiating therapy.

[Analysis of validity and reliability of three radiographic classification systems for preoperative assessment of bone stock loss in revision total hip arthroplasty]. / Gültigkeit und Reproduzierbarkeit radiologischer Klassifikationskriterien des knöchernen Substanzdefekts vor Revisionshüftendoprothetik.

AIM: It was the purpose of this prospective study to analyze validity and reliability of three different radiographic classification systems, which are used to assess bone stock loss prior to revision total hip arthroplasty. METHOD: Investigation was performed using the classification systems according to 1) Paprosky et al., 2) Hungerford et al., and 3) the German Society of Orthopaedics and Traumatology (DGOT). Twenty-eight consecutive patients with diagnosis of aseptic failure of total hip arthroplasty were enrolled in the study. Interrater agreement was analyzed by evaluating the classifications preoperatively by three investigators with different level of clinical experience using a blinded observer technique. Validity was analyzed by comparison of preoperative radiographic findings (n = 3) and an intraoperative control by visualization and palpation (n = 1). Spearman coefficient of correlation (r(s)) was used to establish levels of agreement among multiple ordinal variables. RESULTS: Interrater reliability testing using paired comparison between the three investigators revealed non-homogeneous coefficients of correlation (r(s): Paprosky femur: 0.45 - 0.67, acetabulum: 0.38 - 0.63; Hungerford: 0.46 - 0.66; DGOT femur: 0.38 - 0.59, acetabulum: 0.42 - 0.76). Paired analysis of correlation between preoperative and intraoperative findings again showed non-homogeneous coefficients of correlation (r(s): Paprosky femur: 0.59 - 0.68, acetabulum: 0.39 - 0.70; Hungerford: 0.39 - 0.74; DGOT femur: 0.44 - 0.60, acetabulum: 0.36 - 0.76). In general, defects were grossly underestimated preoperatively. The level of experience did not influence the validity of measurements. CONCLUSION: Our results indicate that these classifications do not provide valid and reliable assessment of femoral and acetabular bone stock loss prior to revision total hip arthroplasty.

Cryopreservation with dimethyl sulfoxide sustains partially the biological function of osteochondral tissue.

The clinical routine use of bone allograft transplants dates back to the discovery that grafts devitalized by freezing bear a reduced antigenicity. Graft failures, caused by a host versus graft reaction, however, remain a clinical problem. Previous investigations on pancreatic islet allografts revealed improved survival and biological function when fast cryopreservation (-70 degrees C/min) was performed in the presence of dimethyl sulfoxide (DMSO). The aim of this study was to determine the effect of fast freezing using DMSO on the biological function of osteochondral tissues. Organ culture was performed with neonatal femora of mice, untreated, rapidly frozen (-70 degrees C/min) with DMSO, or frozen without DMSO. After the culture, tissue morphology, cellular proliferation, osteoblast function, osteoclasts, and the presence of antigen-presenting cells were investigated. In untreated control femora histology appeared normal and proliferating and collagen-synthesizing osteoblasts, osteoclasts, and B-cells and macrophages were present. In frozen femora (with and without DMSO) a disintegration of the periosteum and the epiphyseal growth plate were observed and no active osteoblasts could be detected. Osteoclasts were partially detached from the bone surface. Cell proliferation was fully blocked in femora frozen in the absence of DMSO, while freezing in the presence of DMSO preserved cell proliferation in the medullary canal. The proliferating cells do not express epitopes present on the cells of the B-cell or macrophage lineages. Although the biological function of osteoblasts and osteoclasts was lost upon freezing of osteochondral tissue, DMSO included in freezing protocols preserves some residual cell viability which may be of importance for early graft revascularization as has been previously demonstrated by our group.

[Early damage to the acetabular cartilage in slipped capital femoral epiphysis. Therapeutic consequences]. / Frühe Schädigung des azetabulären Knorpels bei der Epiphyseolysis capitis femoris Therapeutische Konsequenzen.

Epiphyseolysis capitis femoris represents the most common disorder of the adolescent hip, which is followed by a significant rate of early osteoarthrosis. Based on intraoperative findings during the surgical management of 23 hips with epiphyseolysis, early acetabular cartilage abrasion by a cam effect and acetabular rim impingement elicited by the prominent femoral metaphysis have been identified. Both phenomena cause direct damage to the hip joint, especially during flexion and flexion/internal rotation of the hip. As evidenced during surgery, the prominent and sometimes sharp-edged anterior neck metaphysis leveling or exceeding the femoral head showed marks of contusion and the labrum revealed erosions, scars, or tears. Moreover, adjacent acetabular cartilage damage was present ranging from superficial abrasions to a full thickness cartilage loss propagating into the weight-bearing area. In all patients the femoral head cartilage was intact; no avascular necrosis was present. These findings suggest that osteoarthrosis is triggered by direct mechanical damage in the epiphysiolysis hip already during the process of slipping and that chondrolysis appears to represent just the most severe form of this cartilage damage. Consequently, we propose that treatment should not only address the avoidance of a further slippage but also the prevention of impingement and cam leading to early acetabular cartilage damage.

Development of transplanted fetal bones: differences between isografts and allografts in mice.

Allogeneic bone from bone banks frequently is used when large skeletal defects have to be bridged in orthopaedic surgery. Beside immunologic rejection of the graft, the loss in osteogenic potential caused by bone banking procedures may be a major reason for limited clinical success. Similar problems as described for bone have occurred with cartilage and osteochondral transplants. Improving the properties of allogenic bone so that its biologic activity becomes comparable to autologous bone could be substantially beneficial for the outcome of allograft transplantation. To dissect the steps involved in the integration of a fetal osteochondral graft as it matures to bone, the current study compared the development and biologic function of metatarsals from 18-day-old fetal mice freshly transplanted in three different immunologic settings. Morphologic assessment of (1) isografts and (2) allografts in nonsensitized hosts 12 days after transplantation revealed that the grafts bear an intrinsic potential to develop after transplantation. In allografts in nonsensitized hosts, however, a slight alteration in biologic activity as compared with isografts could be detected already in this early phase after transplantation by in situ hybridization for messenger ribonucleic acids encoding extracellular matrix proteins. (3) In contrast to isografts and allografts in nonsensitized hosts, morphologic features and biologic function of allografts transplanted to presensitized hosts were altered severely.

Quantitative assessment of angiogenesis and osteogenesis after transplantation of bone: comparison of isograft and allograft bone in mice.

We performed a vital microscopic study in mice bearing dorsal skinfold chambers to characterize microvascular perfusion and leukocyte/endothelium interaction and their effects on elongation and mineralization of neonatal isograft and allograft bone. Isograft (C57/BL to C57/BL) and allograft bone (C57/ BL to BALB/C) revascularized simultaneously. However, vascular perfusion and density were lower in allograft bone than in isograft bone. Leukocyte/endothelium interaction was the same in isograft and allograft bones. Revascularization was not detected in allograft bone transplanted to presensitized recipients. Moreover, in preexisting vessels at the transplantation site, leukocyte/endothelium interaction was altered in allograft bone of presensitized recipients, despite a normal systemic leukocyte count. Femoral growth resulting from thickening of both epiphyses did not differ between experimental groups, however, mineralization occurred in isograft bone only. Isograft bone was histologically intact, allograft bone hypovital and allograft bone in presensitized recipients necrotic 12 days after implantation. Our findings suggest that graft incorporation or rejection is mediated by the microvasculature and that presensitizing of recipients accelerates rejection of allograft bone.

The connective-tissue envelope in revascularisation of patellar tendon grafts.

Free patellar tendon grafts used for the intra-articular replacement of ruptured anterior cruciate ligaments (ACL) lack perfusion at the time of implantation. The central core of the graft undergoes a process of ischaemic necrosis which may result in failure. Early reperfusion of the graft may diminish the extent of this process. We assessed the role of peritendinous connective tissue in the revascularisation of the patellar tendon graft from the day of implantation up to 24 days in a murine model using intravital microscopy. The peritendinous connective-tissue envelope of the graft was either completely removed, partially removed or not stripped before implantation into dorsal skinfold chambers of recipient mice. Initial revascularisation of the grafts with preserved peritendinous connective tissues began after two days. The process was delayed by five to six times in completely stripped patellar tendons (p < 0.05). Only grafts with preserved connective tissues showed high viability whereas those which were completely stripped appeared to be subvital. The presence of peritendinous connective tissues accelerates the revascularisation of free patellar tendon grafts.