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This prospective study investigated revision after modular short stem implantation. Results are presented for 2 different types of neck adapters (titanium and cobalt-chromium [CoCr]). Eighty-five patients with titanium adapters and 87 patients with CoCr adapters underwent follow-up examination after an average of 5.7 and 5.2 years, respectively. Mean patient age was 57 years in both groups. Indications were primary osteoarthritis (80%), cup dysplasia (14%), and other (6%). Mean Harris Hip Scores were 98 and 99 points (titanium and CoCr groups, respectively). Ninety percent and 96% of patients were very satisfied or satisfied (titanium and CoCr groups, respectively); 3% of patients in both groups were dissatisfied. Pain decreased from visual analog scale score 7 and 6 preoperatively to 0.37 and 0.15 postoperatively for the titanium and CoCr groups, respectively. No joint dislocation occurred. Six patients needed revision within the first year (2 for infection, 1 for via falsa position, and 2 for aseptic loosening in the titanium group, and 1 for aseptic loosening in the CoCr group). Nine revisions occurred due to neck adapter failure (titanium group). Primary standard stems were used in all revisions. Excluding material-related adapter failures in the titanium group, the 5-year survival rate was 94.8% (95% confidence interval [CI], 88.9-97.6 for titanium) and 99% (95% CI, 93.7-99.8 for CoCr). No radiographic signs of loosening were seen at last follow-up. Fine sclerotic lines were detected in Gruen zones 1 (17.2%) and 2 (14%), hypertrophies in zone 3 (4.3%), and periprosthetic cancellous bone compressions in zone 6 (75.8%). No adapter fractures occurred for CoCr components. The treatment and anchoring system of the short stem studied yielded good results and allowed revision using standard stems in all patients., (Copyright 2015, SLACK Incorporated.)

Hip prosthesis stems with a short stem length and proximal fixation geometry support a bone-preserving and muscle-sparing implantation and should also allow for revision surgery with a standard hip stem. We present 250 prospectively documented clinical and radiological results from the Metha Short Hip Stem prosthesis (B. Braun-Aesculap, Tuttlingen, Germany) after an average follow-up of 4.9 years. The average patient age at surgery was 60 years. Indication for total hip replacement was primary osteoarthrosis (OA) (78% of patients), OA based on developmental dysplasia of the hip (16%), and other indications (6%). At the last follow-up, the average Harris Hip Score was 97 points. 85% of patients were very satisfied and 14% were satisfied after surgery, whereas 1% were dissatisfied. Pain according to the Visual Analogue Scale improved from 7.4 (min 1.6, max 9.5) pre-operatively to 0.23 (min 0, max 6.6). No joint dislocations occurred when predominantly using 28 mm and 32 mm prosthesis heads. Nine short-stems were revised: three after bacterial infections, two after primary via valsa with penetration of the femoral cortex two and three months after surgery, and three after early aseptic cases of loosening within the first year. A further nine osseously consolidated short-stems had to be replaced due to breakage of the modular titanium cone adapter after an average of 3.1 years (min 1.9, max 4.4). All surgical revisions were performed using primary standard stems. Without taking the material-related adapter failures into account, a five year Kaplan-Meier survival rate of 96.7% (95% confidence interval 93.4-98.3) was determined for the short-stem prostheses. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination. Fine sclerotic lines were detected in Gruen's AP zones 1 (19%) and 2 (10.5%), individual hypertrophies in zone 3 (3.5%), fine seams in zones 4 (5.5%) and 5 (4%), without pedestal formations in zone 4, clear cancellous bone compressions in zone 6 (97.5%), as well as single fine scleroses (1.5%) and atrophies (2.5%) in zone 7. The mid-term clinical results with periprosthetic bone remodeling and without radiological signs of loosening confirm this metaphyseal short-stem treatment and fixation concept and the possibility of revision surgery using standard hip stems. Long-term results must be further observed on a prospective basis as part of this collective study.

Purpose: This pilot study systematically examined the correlations between the outcome variables pain intensity, disability and health-related quality of life (HRQOL) and between these outcomes and known psychological risk factors for chronic low back pain (CLBP), such as depression, trait anxiety, avoidance- and endurance-related pain responses at two different assessment points., Method: Data from 52 CLBP inpatients treated in an orthopedic clinic were investigated at two points in time: during the first days after admission and 6 months after the termination of the inpatient treatment. Bivariate relationships between pain intensity, disability, HRQOL and psychological variables were examined with the help of Pearson product moment correlations. Furthermore, the differences that exist between correlations at baseline and follow-up were tested for significance., Results: Significant and large differences were found between the correlations with low correlations at baseline and high correlations at the follow-up. Furthermore, HRQOL showed a positive correlation with endurance-related and a negative correlation with avoidance-related pain responses., Conclusions: Focusing on a systematic comparison of two significant assessment time points in CLBP with an acute exacerbation at baseline, the results of this study underlined the recurrent course of LBP. The results highlight that the assessment time points play an important role in CLBP., Implications for Rehabilitation: • Low back pain is a major public health problem with high direct and indirect back-pain-related costs. • Chronic low back pain is a disabling disease which restricts quality of life. • Psychological factors may have a larger impact on disability and quality of life than pain itself. • The recurrent course of low back pain highlights the importance of multidisciplinary pain management even during acute exacerbations of pain.

Background: The variables pain intensity (SI), disability (DS) and quality of life (QoL) belong to a set of primary patient-based outcomes in chronic low back pain (CLBP). The avoidance-endurance model (AEM) assumes three maladaptive and one adaptive pain response pattern. The purpose of this study was to study the level and course of the outcomes with regard to the four AEM patterns., Patients and Methods: A total of 52 CLBP inpatients were investigated at 2 points in time: during the first days after admission and 6 months after the acute exacerbation of pain. Differences between AEM patterns were analyzed with repeated measurement analyses of variance., Results: Groups differences were found for SI (F((3, 48))=2.82, p<0.05), general (F((3, 48))=6.78, p<0.05) and health-related QoL (F((3, 48))=5.99, p <0.05). In contrast, for the variable disability only a significant time effect was found., Conclusion: The results show differences in the level and process of SI, DS and QoL between the subgroups. An AEM-based classification of subgroups is also reasonable for CLPB patients., (© Deutsche Gesellschaft zum Studium des Schmerzes)

Cyclo-oxygenase-2 selective inhibitors are frequently used to manage osteoarthritis. We compared the analgesic efficacy of the novel cyclo-oxygenase-2 selective inhibitor lumiracoxib (Prexige) versus placebo and celecoxib in patients with knee osteoarthritis. This seven day, double-blind, placebo and active comparator controlled, parallel group study included 364 patients aged > or = 50 years with moderate-to-severe symptomatic knee osteoarthritis. Patients received lumiracoxib 400 mg/day (four times the recommended chronic dose in osteoarthritis; n = 144), placebo (n = 75), or celecoxib 200 mg twice daily (n = 145). The primary variable was actual pain intensity difference (100 mm visual-analogue scale) between baseline and the mean of three hour and five hour assessments after the first dose. Actual pain intensity difference, average and worst pain, pain relief and functional status (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) were measured over seven days. Patients also completed a global evaluation of treatment effect at study end or premature discontinuation. For the primary variable, the superiority of lumiracoxib versus placebo, the noninferiority of lumiracoxib versus celecoxib, and the superiority of lumiracoxib versus celecoxib were assessed by closed test procedure adjusting for multiplicity, thereby maintaining the overall 5% significance level. In addition, celecoxib was assessed versus placebo in a predefined exploratory manner to assess trial sensitivity. Lumiracoxib provided better analgesia than placebo 3-5 hours after the first dose (P = 0.004) through to study end. The estimated difference between lumiracoxib and celecoxib 3-5 hours after the first dose was not significant (P = 0.185). Celecoxib was not significantly different from placebo in this analysis (P = 0.069). At study end 13.9% of lumiracoxib-treated patients reported complete pain relief versus 5.5% and 5.3% of celecoxib and placebo recipients, respectively. WOMAC total and subscales improved for both active treatments versus placebo except for difficulty in performing daily activities, for which celecoxib just failed to achieve significance (P = 0.056). In the patient's global evaluation of treatment effect, 58.1% of patients receiving lumiracoxib rated treatment as 'excellent' or 'good', versus 48.6% of celecoxib and 25.3% of placebo patients. Lumiracoxib was well tolerated. The overall incidence of adverse events was similar across treatment groups.

Purpose: The long-term outcome of this new endoscopic technique was compared with that of the classical open Hohmann procedure., Type of Study: Retrospective cohort study., Methods: During 1992 and 1995, 37 patients were surgically treated with the Hohmann procedure after failed intensive conservative treatment. At an average of 92 months after the operation, 30 patients (81%) could be clinically re-examined and were evaluated with a standard questionnaire including the scores of Roles and Maudsley and Morrey et al., Results: Twenty of these patients were treated endoscopically and 10 with the open technique. There were no differences in demographic data between the 2 groups. At follow-up in both groups, similar results were seen for the function of the elbow, the scores of Roles and Maudsley and Morrey et al., the subjective rating of pain and function of the elbow, and complication rate. The results in the score of Morrey showed an average scoring of 93.2 for the endoscopic group and 87.5 for the open group (P > .05)., Conclusions: The endoscopic technique showed results comparable to the open technique and can therefore be recommended for wider surgical use so as to learn more details concerning possible complications and results of the new technique., Level of Evidence: Level III, retrospective cohort study.

Background: To compare the in vitro effects of selective COX-2 inhibitors (L-745,337, NS-398 and DFU) and of COX-unspecific diclofenac on release of PGE(2 )and 6-keto-PGF(1alpha) from inflamed bursa subacromialis tissue (IBST) obtained from a total of 35 patients with shoulder impingement syndrome (SIS)., Patients and Methods: Bursal specimens were incubated in the presence of drugs (0.01-1000 microM) for 20 min and 16 h., Results: After 20 min 10 microM diclofenac significantly inhibited formation of PGE(2) and 6-keto-PGF(1alpha), whereas L-745,337 and NS-398 (10-1000 microM) induced significant inhibition only at concentrations > or =100 microM. In contrast to equimolar diclofenac, DFU (0.01-10 microM) induced no inhibition of bursal PGE(2) release but a dose-dependent, although statistically not significant inhibition after 16 h. The inhibitory potency of diclofenac (0.01-10 microM) was even more increased during long-term incubation showing greater inhibition than DFU at all concentrations studied., Conclusion: The data suggest that in IBST in SIS in vitro the majority of PG is generated via the COX-1 pathway.

Objectives: To investigate the relative contribution of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2 to prostaglandin E2 (PGE2) release from inflamed synovial tissue in N=10 patients with primary osteoarthritis (OA) in vitro and to determine possible effects of COX inhibitors on the gene expression of synovial COX-1 and COX-2., Design: The effects of a COX-unspecific nonsteroidal anti-inflammatory drug (NSAID; diclofenac), a selective COX-1 inhibitor (SC-560) and a selective COX-2 inhibitor (SC-58125) on PGE2 release from inflamed synovial tissue (0.1-10 microM, 3 and 6 h incubation time) were compared. Release of PGE2 into the incubation media was measured by means of the enzyme-linked immunosorbent assay. Expression of synovial COX-1/-2 was quantified by means of real-time reverse transcriptase polymerase chain reaction (RT-PCR)., Results: All agents inhibited synovial PGE2 release dose-dependently. Compared to short-term incubations, the inhibitory potency of diclofenac, SC-58125 and SC-560 was increased (0.1-10 microM) and decreased (0.1-1 microM), respectively, during 6 h: At 10 microM, SC-560 and SC-58125 had obviously lost their specificity for COX-1 and COX-2, respectively, indicated by a comparable inhibitory potency of the selective COX-1 inhibitor (86.6%) and the selective COX-2 inhibitor (96.6%) within identical tissue specimens. In contrast, at 1 microM, 83% and 62.8% inhibition was seen for diclofenac and SC-58125, respectively. SC-560 showed 30.6% inhibition (P<0.05). In contrast to synovial COX-1, RT-PCR revealed a significant induction of COX-2 through PGE2., Conclusions: With respect to the concentrations studied, the data suggest that in inflamed synovial tissue in OA, up to 30% of PGE2 might be generated via the COX-1 pathway. In therapy of OA, the relative contribution of COX-1 in synovial inflammation should be considered, weighing the potency of COX-unspecific NSAID against the assumed superior gastrointestinal safety profile of selective COX-2 inhibitors.

Surgical treatment of lumbar spinal stenosis is aimed at decompressing the structures of the spinal canal. Several surgical techniques have been described over the last few years. This article gives a survey of the surgical procedures used for the treatment of spinal stenosis. When comparing and discussing indications and current surgical techniques used for spinal stenosis, one can describe some general tendencies: if the symptoms are severe or disabling and do not respond to appropriate conservative treatment, or if the patient is not able to cope with the pain any longer and views his or her quality of life as unacceptable, surgery is indicated. If the symptoms are mainly radicular, (microsurgical) decompression should be performed. If back pain is the main problem combined with preoperative evidence of segmental instability, spondylolisthesis, or scoliosis, one should consider spinal fusion in addition to an appropriate decompression. Further investigations are necessary to exactly find out the appropriate indications for a fusion and to answer the question of whether spinal instrumentation should be used.

Thirty-eight patients with chronic calcifying tendinopathy of the shoulder were randomized prospectively into two groups: 19 patients had endoscopic decompression and 19 had open decompression. Thirty-three patients (19 with open and 14 with endoscopic decompression) were available for followup. Clinical and ultrasonographic investigations were done at followup. The purpose of the current study was to evaluate prospectively the clinical and sonographic results after open decompression and after endoscopic decompression. Apportionment of age and gender was similar in both groups. The followup was 15.7 months for patients after open decompression and 17.1 months for patients after endoscopic decompression. The average Patte score was 84.5 points (84.4 for patients who had endoscopic decompression and 84.6 for patients who had open decompression). Corresponding results were found with a Constant and Murley score of 96.6 points (97.6 for patients who had endoscopic decompression and 95.8 for patients who had open decompression). In the endoscopic group physiotherapy was recommended for 5 weeks more than in the open surgery group. Similar results were seen for the incapacity to work in both groups with 4.6 weeks for the patients who had endoscopic surgery and 5 weeks for the patients who had open surgery. No nerve injuries, wound infections, or other postoperative complications were found. Comparison of both surgical methods showed good clinical and score results. Endoscopic and open surgery are equally effective in the treatment of chronic calcifying tendinopathy.

Study Design: Evaluation of 1054 patient charts and 100 random roentgenogram charts as well as clinical investigation of 39 patients., Objectives: Noncontiguous unstable spine fractures are rare, easy overlooked, and difficult to treat. The purpose of the study was to evaluate the delay in diagnosis and clinical and radiologic outcome of these fractures., Summary of Background Data: Noncontiguous spine fractures are reported in about 1.6-16.7% in the literature. In most of the studies stable fractures, which did not need any special treatment, were also included. Therefore, in this study only unstable fractures requiring treatment were reinvestigated., Methods: A total of 1054 patients with fractures of the spine were treated over a period of 14 years in the spinal cord injury unit and retrospectively reviewed; 141 (13.4%) of the patients had multiple fractures, but only 39 (3.7%) had a noncontiguous spine fracture, most frequently from a fall or jump from a greater height, or traffic accidents., Results: Thirty patients (76.9%) had all fractures diagnosed at the first examination. Nine patients (23.1%) had a delayed diagnosis of the secondary lesion, but this delay resulted in no neurologic deterioration. A total of 32 extraspinal injuries were diagnosed and treated 14 times surgically. Loss of correction was seen after surgical treatment (n = 21), and increasing deformity occurred after conservative treatment (n = 18). The neurologic deficit improved in 10 conservatively (4) and operatively (6) treated patients and deteriorated in one patient after surgery., Conclusion: A delayed diagnosis of the second fracture was frequently seen without clinical consequences, and neurologic improvement occurred after conservative and operative treatment. Surgical treatment resulted in significantly earlier mobilization and less kyphotic deformity.

Identification and treatment of spinal disorders have been described for thousands of years. Nevertheless, systematic operative treatment was more or less impossible until about 200 years ago. During the second half of the last century, spinal surgery developed rapidly due to several technical improvements. This article summarizes the main aspects of the historical development of spinal surgery.

Study Design: A 5-year clinical follow-up assessment of a prospective randomized study of chemonucleolysis using chymopapain (4000 IU) or collagenase (400 ABC units) was performed., Summary of Background Data: Intradiscal therapy can be performed for patients with contained discs by chemonucleolysis, percutaneous discectomy, or laser ablation. The oldest intradiscal therapy is chemonucleolysis with chymopapain., Objective: The purpose of this study was to compare prospectively the efficacy of chymopapain and collagenase for intradiscal injection., Methods: In this study, 100 patients with indication for intradiscal therapy were prospectively randomized to treatment with either chymopapain or collagenase. All the injections were performed by the double-needle technique with the patient under general anesthesia. The mean age of the patients was 35.5 years in the chymopapain group and 38 years in the collagenase group. An equal number of injections was performed at L4-L5 and L5-S1., Results: After 5 years, good and excellent results were observed in 72% of the chymopapain group and 52% of the collagenase group when the surgically treated and lost patients were graded as poor. Using a scale of 0 (no pain) to 10 (intractable pain), the pain level dropped from 8.5 to 0.7 in the chymopapain group and from 8.6 to 0.9 in the collagenase group. Microdiscectomy at the injected level was required for 23 patients (14 in the collagenase group and 9 in the chymopapain group)., Conclusions: After 5 years, no deterioration had occurred, as compared with the 1-year follow-up assessment. Chymopapain has proved to be safe, with one minor anaphylactic reaction, and effective even over the long term. Collagenase may need further study and cannot be recommended at this time.

Conservative or operative treatment for rotator cuff calcifying tendinitis was investigated in 100 patients in a matched-pair analysis. They were examined clinically and ultrasonographically 35-60 months after the initial visit. The mean Patte score was 91.8 for the patients who underwent surgical treatment and 81 for the ones who received conservative therapy (p < 0.004), while the age-related Constant-score was 103.4 and 95, respectively. Ultrasonography showed 28% calcifications in the surgical group, 18% newly formed and 10% that did not resolve after surgery. In the conservatively treated group, 33% calcifications were seen, of which 67% resolved. The number of rotator cuff ruptures was significantly higher in the conservative group. In the surgical group, 2% of partial tears and in the conservative group 5% of partial and 4% of complete cuff ruptures were found. Conservative treatment for calcifying tendinitis leads to less favourable pain results in the long term than surgical treatment. Surgery shortens the painful period and may reduce the number of future rotator cuff ruptures. Finally, the subjective functional outcome is significantly better after surgery.

Purpose of the Study: Aim of this investigation was the examination of the therapeutic effect of cervical nerve infiltration with mepivacaine in comparison to local applications of isotonic sodium chlorid solution in a prospective randomised double blind study., Methods: 57 patients with cervicocephalgia or cervicobrachialgia were injected daily with mepivacaine ( n=28) or physiological sodium chlorid solution ( n=29). The success was judged through the blinded patients and blinded therapists first after three days of treatment. If no improvement occurred a single injection of mepivacaine and triamcinolonacetonid was given. This injection could be repeated if required. At the end of the inpatient treatment, after a mean of 14 days, the patients assessed the treatment according to a scale of 1-4 (painfree - no improvement)., Results: The average therapeutic effect, in the subjective appraisal of 1-4 by the patients, was 2.15 in the mepivacaine-group and 2.54 in the sodium chlorid - group. In the mepivacaine-group no pain (note 1) was achieved two times and 21 times a clear improvement (note 2), while in the sodium chlorid - group 18 times a clear improvement was achieved and never freedom of pain ( p<0,038). In the mepivacaine-group twice a steroidinjection was required, while in the sodium chlorid - group this was necessary in 16 cases ( p<0,01)., Conclusion: Cervical injections with mepivacaine improve the subjective pain perception in cervicocephalgia and cervicobrachialgia significantly better than isotonic sodium chlorid - solution in short term results and can therefore be prefered. After an inpatient treatment good and excellent subjective results could be achieved in a high percentage.

Study Design: Load sharing in stabilized spinal segments was evaluated using sequential injury and stabilization with a posterior instrumentation system under an in vitro flexibility protocol., Objective: To analyze the partitioning of applied loads between anatomic and implanted structures of lumbar functional spinal units stabilized with a posterior instrumentation system. To identify surgical indications for which the risk of fixator breakage in vivo is high., Summary of Background Data: Relatively few groups have experimentally measured the in vitro and in vivo forces and/or moments supported by posterior instrumentation systems, and no analysis, of the load sharing in these systems has been performed. This information will provide novel insight into implant fatigue life, and the degree to which the spinal anatomy is shielded from the applied load and will allow the verification of mathematical models for new injury scenarios., Methods: Specimen kinematics were determined using an optoelectronic tracking system. Intradiscal pressure and the forces and moments supported by the implants were measured using, respectively, a needle-mounted pressure sensor and strain gauges mounted on the spinal implants., Results: A large majority of the applied moments were supported by an equal and opposite force pair between the intervertebral disc and fixator rods in flexion and extension and an equal and opposite force pair between the left and right fixator rods in lateral bending. Torsional moments were shared approximately equally between the posterior elements, intervertebral disc, an equal and opposite shear force pair in the transverse plane between the right and left fixators and internal fixator moments., Conclusions: When posterior instrumentation devices are used to stabilize severe anterior column injuries, they are at risk of fracture secondary to reversed bending moments.

Fifty patients with impingement syndrome refractory to long-term conservative treatment were randomized to three treatment groups. All patients received an injection of 10 ml 0.5% bupivacaine, in group 1 without corticosteroid, in group 2 with crystalline corticosteroid and in group 3 with lipoid corticosteroid. Treatment in group 1 had to be stopped because of inefficacy. In groups 2 and 3 favorable results were achieved in 19 out of 40 patients.

The paper presents a European family showing bilateral Madelung's deformity within five consecutive generations. Females as well as males are affected alternately indicating autosomal dominant inheritance. Despite of a body height within the lower normal range in two patients the diagnosis of dyschondrosteosis could not be clearly established as further hints for dwarfism are missing. The etiology of Madelung's deformity may be difficult to establish. There seems to be the possibility of an inheritance independent from the complete syndroma of dyschondrosteosis. Therefore the genetic counselling will always be difficult and has to regard the wide variety of symptoms ranging from little pain and cosmetic disturbance to moderate pain and functional impairment.

Our aim was to determine the amounts of eicosanoids in blood and synovial tissue of patients with knee arthrosis and to examine the effects of 2 doses of tepoxalin (50 mg twice, 200 mg twice), administered p.o. for 3.5 days. Concentrations of leukotriene B4 (LTB4, LTC4, and thromboxane B2 (TXB2) were measured in blood before and after oral administration of tepoxalin and release of prostaglandin E2 (PGE2), 6-keto-PGF1alpha, and LTC4 was measured in incubation media of synovial tissue, taken at surgery from patients treated with tepoxalin. Radioimmunoassay (RIA) was used to determine the levels of the eicosanoids. LT and TXB2 release was reduced by tepoxalin in both doses used. Under these conditions, PGE2, 6-keto-PGF1alpha, and LTC4 release from synovial tissue was detectable only after stimulation with calcium ionophore A23187. Washed synovial tissue, in which tepoxalin concentrations should be reduced, released higher amounts of all eicosanoids measured than directly incubated synovial tissue did. Pain after tepoxalin administration was significantly reduced. Relevant drug concentrations were detected in plasma and synovial fluid. Tepoxalin was well tolerated and had no marked adverse effects. At 400 mg, tepoxalin is a dual inhibitor of cyclooxygenase (CO) and 5-lipoxygenase (5-LO) in blood and synovial tissue.

A series of 60 matched and paired patients with complete rupture of the anterior cruciate ligament (ACL) was studied; 30 were treated conservatively, even though operation was recommended, and 30 were operated on within 35 months (range 18 to 48 months) after the ACL rupture. The average age was 34 years in each group. They were assessed 39 months after arthroscopy or reconstruction. At follow up, no patient had flexion of less than 100 degrees, 13 of the reconstructed knees had an extension deficit, but in only one was this more than 10 degrees. Thirty-six percent of the reconstructed and 14% of the conservatively treated patients graded their sports activity as unlimited, while 13% of the ACL reconstructions and 21% of those treated conservatively were severely limited. The Lysholm, Cincinnati and OAK scores were significantly better in the reconstructions. The anterior drawer sign was positive in 24% of the ACL reconstructions and in 81% of the conservatively treated patients; 19% had a positive pivot shift after reconstruction compared to 75% of those treated conservatively. Even though there was a considerable number of patients with a decreased range of motion after ACL reconstruction because of the slow regime of postoperative mobilisation used, the results of operation are significantly better than after conservative treatment even when ACL reconstruction was carried out late after injury.

Fifty-four consecutive patients were studied prospectively with magnetic resonance imaging before microdiscectomy, and the findings correlated with clinical symptoms before and after operation. A sequestrated fragment was found in 59% of cases, a subligamentous disc sequestration in 25% and a disc protrusion in 16%. The levels operated on were L4/5-36%, L5/S1-62.5%, and one at L3/4; 71% were laterally placed, 10% lay intraforaminal and 10% medial. The diameter of the protrusion was 4 mm to 13 mm for the craniocaudal extension, and 5 mm to 18 mm for the anteroposterior extension. No correlation could be found between a neurological deficit and the size of the prolapse. A positive correlation was present between the increasing degree of canal obstruction and the degree of disc degeneration determined by imaging for extrusions, subligamentous disc sequestrations and free sequestrations. Nerve root inflammation and enlargement was seen in 36% of the images, corresponding to an operative finding of 32%. Magnetic resonance imaging is a helpful pre-operative diagnostic investigation which shows structural changes in the disc and the correct localisation and size of the disc sequestration, but there was no correlation between the imaging findings and the clinical symptoms.

Purpose: The aim of this study is to analyse the mid-term clinical and sonographical results of non-operative therapy of calcifying tendinitis., Methods: Retrospectively the anamnestical, clinical and sonographical results after various non-operative treatment of patients with calcifying tendinitis were reviewed. For this purpose 159 patients with 178 calcifying deposits in the rotator cuff were evaluated on an average of 60 months after their first examination in our clinic (mean age: 49.2 years; sex ratio: 58% women)., Results: During a mean symptomatic period of 49 months, an average of 4.2 different therapeutic modalities were applied. After this time 70% of all patients showed an excellent or good result. With regard to the age-correlated Constant-Score 85% of all patients had more than 81 points, i.e. a good result. The mid-term results on a visual analogous scale from 10 (pain) to 0 (no pain) showed a decrease from 7.7 to 2.2 and this correlated with the shoulder function scores (Constant-/Patte-Score, r -0.8). After an average of 104 months 82% of the hydroxyapatite deposits could not be diagnosed by sonography (7.5 MHz.) anymore., Conclusion: In the treatment of calcifying tendinitis the conservative methods achieve good and excellent results in 70%. Patients should be treated with analgetics, subacromial injections, physiotherapy and ice therapy up to a period of twelve months, above all with small deposits and radiologic resorptive stadiums. The results of this study should be compared with any invasive regimen.

Purpose: Investigation of clinical und ultrasonographical results after operatively treated calcifying tendinitis., Methods: 131 patients with calcifying tendinitis were treated by surgical decompression and, if necessary and possible, calcific deposit removal. 93% of these patients were clinically and ultrasonographically examined after an average time of 4 years and 5 months., Results: Pain rating on a visual analogue scale 0-no pain to 10-maximum pain was 8.7 before surgery and 1.4 at follow-up. 88% of the patients rated the operation excellent or good. The Constant Score results corresponded to the average results of a normal population (100.3). At the time of examination in 16.4% of the cases new calcific deposits could be discovered., Conclusion: According to the clinical results operative treatment shows good and excellent results in a high degree even after unsuccessful non-operative therapy.

Low back pain is the most expensive condition in industrialized countries. Approximately 65-80% of the population will be afflicted with low back pain at some point during their life. Low back pain has many causes and can originate from any of several pain-sensitive foci, among which are facet joints, sacroiliac joint, muscle and ligaments. Primary care in the acute phase consists of nonsteroidal anti-inflammatory drugs to address the biochemical and inflammatory mediators of pain or skeletal muscle spasmolytics to reduce low back pain symptoms. Injection procedures should be reserved for the patients with low back pain who fail to respond to a directed, conservative treatment trial and have had pain for at least 2 weeks duration. Eliminating sensation from a certain pain source has been proposed as a way to allow an examiner to determine if that joint is responsible for the patient's pain. Injections of local anesthetic into the facet joint or around its nerve supply are clinical methods of eliminating pain from focal areas such as facet joints or myofascial trigger points. When a particular joint is determined to be the source of pain, long-term relief can be sought by directing therapeutic interventions at that joint. The anatomic accessibility of the most common pain sources of low back pain make diagnostic blocks and therapeutic instillation of corticosteroids particularly appealing. If used, their potential benefit for the individual case needs to be carefully weighed. They should be used to facilitate more aggressive conservative care and not as an isolated treatment. Certainly, if response to corticosteroids does not occur after the first injection, no further administration of corticosteroids is indicated.

The pharmacological profile of a novel dual inhibitor, tepoxalin and of its carboxylic acid metabolite on cyclooxygenase and lipoxygenase pathways was evaluated by in vitro incubation with synovial tissue. Tissue specimens obtained at surgery in rheumatoid arthritis (RA, n = 10) or osteoarthritis (OA, n = 11) patients were incubated. Tepoxalin (10(-7), 10(-6), 10(-5) M) decreased eicosanoid release calculated in % of tyrode control for OA: LTC4 to 71-33%, 6-keto-PGF1a to 37-20%, PGE2 to 29-6%. For RA: LTC4 to 56-22%, 6-keto-PGF1a to 43-22%, PGE2 to 57-32%. Similarly, its metabolite (10(-7), 10(-5)M) decreased release in OA: LTC4 to 99 and 60%, PGE2 to 42 and 20%, 6-keto-PGF1a to 54 and 25%. In RA:LTC4 to 81 and 45%, PGE2 to 61 and 30%, 6-keto-PGF1a to 46 and 18%. Significance (P < 0.05) was achieved for all but 1 group (LTC4 metabolite at 10(-7)M vs tyrode). In summary a marked and dose dependent decrease of LT and PG release was obtained when incubating the dual inhibitor tepoxalin and its active carboxylic acid metabolite with synovial tissue at doses expected to be reached in the joint during therapy.

The question is, if a possible concentration of stress in the segment adjacent to the fusion level might result in disc degeneration. Two series of patients have been evaluated: One group of 70 patients underwent a posterolateral fusion without instruments and the other group of 69 patients underwent a posterolateral instrumented fusion. The follow-up was in average 5.7 years resp. 4.6 years. The operations were divided in monosegmental, floating and polysegmental fusions. In the total group, 10% of the non-instrumented and 28% of the instrumented patients had an osteoarthritis of the facet joints, 10% resp. 23% were unstable and in 9% resp. 1% a disc resorption occurred. There have been no statistical differences in the both polysegemental groups, but this was the case for all osteoarthritis and instabilities in the monosegmental fusions. It is supposed that the changes in kinematics together with material related alterations of elasticity led to higher stress concentration in case of instrumentation.

Video-laparoscopic transperitoneal ventral fusion of the lumbar spine using the Bagby-and-Kuslich (BAK) interbody fusion system combines the advantages of the conventional transperitoneal approach with the well-known advantages of minimally invasive surgery. According to our experience it is a safe procedure with an acceptable operating time, little postoperative pain, fast recovery and a short postoperative stay in hospital. Long term results need to be observed and further studies made.

The bony reaction after implantation of uncemented ceramics is of special interest. Therefore porous and dense hydroxylapatite and aluminium oxide ceramics were implanted in rat femurs. One group received no surgical manipulation and another with a sham procedure where no ceramics were implanted served as controls. After 6 and 10 days the rat femurs were harvested and the release of PGE2 and 6-keto-PGF1 alpha was measured with specific radioimmunoassays. Decrease in the release of PGE2 from day 6 to day 10 was present in all three implants. In contrast, 6-keto-PGF1 alpha increased from day 6 to day 10. Comparing the ceramic types an increase in 6-keto-PGF1 alpha release was seen in the porous hydroxylapatite group. These prostaglandin (PG) release patterns after ceramic implantation are similar to those of fracture healing, but aluminium oxide seems to be inert, while hydroxylapatite, especially the porous type, stimulates 6-keto-PGF1 alpha release.

Study Design: In human lumbosacral spines, the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular devices during compression and flexion/compression loading were investigated., Objectives: To compare the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular, lumbosacral fixation devices applied to destabilized cadaveric spines, and to determine the effect of each device on the flexibility and intersegmental distraction of the motion segment above each fused segment., Summary of Background Data: The lumbosacral segment is the most mobile region in the lumbar spine, exhibiting the highest range of motion in both flexion and extension. Therefore, the fixation of this and the adjacent segment is of special clinical interest., Methods: L5-S1 facetectomy or L5 laminectomy procedures were performed on cadaveric human lumbosacral spines. Fixation devices then were applied across one or two levels, and intersegmental motion under flexion/compression or under pure compression loads was monitored., Results: The flexibility and posterior strain allowed by the four implants did not differ significantly between implants. The strain across the stabilized site (monosegmental and bisegmental) was below 10% for all devices tested. The flexibility and distraction were reduced to levels below intact after the fixators were applied. The distraction across the segment above the fusion was not increased because of fixation with these four fixators., Conclusions: Angular stable fixation devices, such as those described here, provide adequate stabilization of the posteriorly destabilized spine.

The implantation of fixation devices increases the primary stability after surgery significantly. Little is known about the comparison of flexibility of instrumented and posterolateral fusions or the lumbosacral distractions spondylodesis (LSDS). The purpose of the study was to compare the flexibility of instrumented and posterolateral fusions or LSDS after simulation with polymethylmethacrylate (PMMA). Dynamic testing from 0-16 Nm in flexion/compression and 0-900 N in compression was performed on 14 lumbosacral spines. The spines were tested intact, after laminectomy, instrumentation with an internal fixateur L5-S1, and simulation of posterolateral fusion L4-S1 or LSDS and thereafter a pseudoarthrosis was simulated. The laminectomy resulted in a significant increase of flexibility and posterior distraction in flexion and compression. The stabilization with an internal fixateur or PMMA simulation for posterolateral fusion or LSDS resulted in a significant decrease of the flexibility. Creation of a unilateral pseudoarthrosis did not effect the flexibility. The instrumented fusion as well as the PMMA simulated bony posterolateral fusion and LSDS resulted in this model in a significant stabilization of the laminectomy. After unilateral fusion the flexibility was not significantly increased.

Objectives: The authors measured prostaglandin (PG) and leukotriene (LT) release from human disc and lumbar facet joint tissues., Summary of Background Data: High levels of phospholipase A2 (PLA2) have been measured in the human disc. PLA2 releases fatty acids from lipid membranes. These can be converted to PG and LT, which are potent inflammatory mediators and supposed to be involved in lumbar diseases., Methods: The tissues were obtained during surgery and incubated in Tyrode's solution. PG and LT release was measured radioimmunologically from the supernatant., Results: Disc (4 ng/g wet weight), cartilage (21 ng/g wet weight), and bone (14 ng/g wet weight) released PGs but no LTs., Conclusion: Because PG release from sequestrated disc is rather low, the inflammatory effect might be more because of immunologic reactions.

Diskectomy, chemonucleolysis, percutaneous diskectomy, and laser ablation are used to treat patients with sciatica. The effects of percutaneous diskectomy on the intradiscal pressure of the human disk are not known. Our aims were to determine (a) whether removal of nucleus through automated percutaneous diskectomy significantly reduces intradiscal pressure without altering the disk geometry and stiffness, and if so, how much nucleus removal is required to achieve these goals; and (b) whether the effects of conventional diskectomy on these same parameters are equivalent to removal of nucleus through automated percutaneous diskectomy. Cyclic compressive loads of 20-900 N were applied to lumbar disks. Conventional diskectomy or automated percutaneous diskectomy (performed for 40 min with biomechanical measurements made four times at 10-min intervals) was then performed under zero load and the specimens retested under the same cyclic compressive loading. There were significant (p < 0.01) decreases in intradiscal pressure (by 7% under 900 N) after 10 min of automated percutaneous lumbar diskectomy. There were no further significant decreases in pressure during the next 30 min of percutaneous diskectomy. There were also significant decreases in pressure due to a puncture hole made with the Nucleotome trephine alone, without removal of disk material, and there was no difference in pressure after trephining alone and after percutaneous diskectomy. Decreases in disk height were significant, ranging from 5% at 10 min to 7% at 40 min of treatment. There were equivalent decreases in intradiscal pressure and disk height due to removal of similar amounts of nucleus during conventional diskectomy and during 40 min of percutaneous diskectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

This study investigated (1) the effect of screw diameter and insertion technique in lumbar vertebrae, and insertion site in the sacrum, on the axial pullout force and transverse bending stiffness of pedicle screws, and (2) the effect of bone cement augmentation using polymethylmethacrylate (PMMA) and the biodegradable composite, poly(propylene glycol-fumarate) on axial pullout force and transverse bending stiffness of pedicle screws inserted into lumbar vertebrae. The axial pullout force and transverse bending stiffness of a 6.25-mm Steffee screw and a 6-mm Kluger screw did not differ significantly in vertebral bodies of similar equivalent bone mineral density. The axial pullout force of Schanz screws was significantly increased with a 1-mm increase in screw diameter. However, there was no significant increase in transverse bending stiffness. In the sacrum, an approach through the S1 facet produced significantly higher axial pullout forces and transverse bending stiffness than the approach described by Harrington and Dickson. PMMA and a biodegradable composite bone cement poly(propylene glycol-fumarate) both increased the axial pullout force. PMMA also increased the transverse bending stiffness.

Objective: To determine the major source of eicosanoid release in arthritic joint tissues and to examine the modulation of this release by indomethacin and diclofenac., Methods: Release of prostaglandin E2 (PGE2), 6-keto-PGF1 alpha, leukotriene B4 (LTB4), and LTC4 was measured in supernatants of synovial tissue, cartilage, and bone incubates from patients with osteoarthritis, active rheumatoid arthritis (RA), inactive RA, and pseudogout. Radioimmunoassay (RIA) was used to determine the levels of the eicosanoids., Results: Addition of the divalent cation ionophore A23187 resulted in significant release of all eicosanoids measured from synovial tissue, but not from cartilage, cortical bone, or cancellous bone. PG release was significantly inhibited by the addition of indomethacin or diclofenac at either 10(-5) moles/liter or 10(-7) moles/liter. The amount of LTC4 released from cartilage and bone was only slightly above the detection limit of the RIA, whereas large amounts were released from synovial tissue. Neither indomethacin nor diclofenac had an effect on LTC4 release. LTC4 release from synovial tissue of patients with inactive RA was significantly decreased in comparison with the levels from synovial tissue of patients with the other joint diseases. There was no significant difference in PG release among patients in the various disease groups., Conclusion: Synovial tissue appears to be the major source of eicosanoids in synovial fluid. Indomethacin and diclofenac inhibit the release of PG, but not LT, from various joint tissues.

To investigate the relationship between the type of hyperextension injuries and the conditions producing them, nine cervical specimens (occiput to T1) were loaded to failure in tension at a fixed extension angle of 30 degrees. Under these loading conditions, specimens failed at average tensile loads and extension moments of 499 +/- 148 (SD) N and 4.0 +/- 3.1 Nm, respectively. Failure occurred at an average tensile displacement of 18.8 +/- 7.7 mm. The anterior longitudinal ligament ruptured and the intervertebral disc failed in at least one level in all specimens. In four specimens, the disc failed at an additional level, leaving the anterior longitudinal ligament intact at that site. With one exception, all injuries occurred in the lower cervical spine (C5-C6 and C6-C7), the region most often injured in vivo. The location of the injuries was associated with the degree of degeneration of the facet joints and the discs. The discs of the lower cervical spine were significantly more degenerated than those at the C2-C3 level. In addition, the degree of disc degeneration in the noninjured discs was significantly less than in the injured discs. These data help quantify the threshold of injury and the patterns of tissue damage resulting from hypertension loading of the cervical spine.

Various methods of lumbosacral fusions for the treatment of degenerative spinal diseases are used clinically. Results vary greatly depending on indication, type of fusion, implants, and method of evaluation. In a retrospective clinical and radiological examination after an average follow-up time of 3.9 years this study reports on the outcome of lumbosacral distraction spondylodesis (LSDS) in a consecutive series of 147 patients being fused for the treatment of spondylolisthesis, failed-back syndrome, or lumbar instability. LSDS consists of a posterolateral fusion together with an autologous corticocancellous H-graft wedged under distraction between the spinous processes of L4 and S1. With 81.0% good and excellent results this noninstrumented fusion technique showed the best outcome in patients with spondylolisthesis, while in cases with a failed-back syndrome or lumbar instability only 62.3% excellent to satisfying outcomes were noted. The rate of pseudarthrosis was 13.6% in the whole patient group; no major complications such as nerve root damage, postoperative neurological deficits, or spinal stenosis were found.

Clinical failures of internal fixation implants for the treatment of the thoracolumbar spine are generally attributed to fatigue. Few studies, however, have characterized changes in fixation rigidity with time or subjected spine-implant fixation constructs to fatigue loading until failure. Fatigue characteristics of five dorsally applied spinal fixation implants were determined using lumbosacral calf spines, with an L3 vertebrectomy, loaded cyclically in combined compression (maximum 605 N) and flexion (maximum 16 Nm) for up to 100,000 cycles. Displacement transducers monitored motion at the site of instability and at the segment above the implants. Flexibility and strain at these segments were then calculated. A one-way analysis of variance showed that there were no significant differences in flexibility of the five fixation constructs (P greater than .05). A multiple Bonferroni test revealed that the AO and Kluger fixateur interne and Steffee plates, with fixation at L2 and L4, allowed significantly more strain (P less than .01) across the site of instability than did Harrington rods and Luque plates with fixation at L1, L2, L4, and L5. There were no significant differences between fixation constructs in initial strain above the implants. After 10,000 cycles, however, there were significant increases in strain across the segment above the Luque and Harrington implants (P less than .05). Failure of the AO Schanz screw occurred in three of six constructs at a mean of 73,300 cycles. The Steffee screws failed in four of five constructs at a mean of 20,800 cycles. The rods of the Kluger fixateur interne broke in four of five constructs at a mean of 47,800 cycles, and one screw slipped at 11,000 cycles. There were no metal failures in the Harrington or Luque implants.(ABSTRACT TRUNCATED AT 250 WORDS)

From 1978 through 1987, 86 patients with epicondylitis were admitted for surgery after failed conservative treatment. The Wilhelm technique was performed either alone or in combination with an intraarticular procedure. The Wilhelm technique involves denervation of the epicondyle. The intraarticular procedure described by Bosworth or Boyd involves a one-third resection of the orbicular ligament and resection of a synovial fold. Before surgery a local anesthetic was injected at the sore spot of the epicondyle. After almost complete pain relief after injection, a sole Wilhelm procedure was performed at the lateral epicondyle in 34 patients and at the medial epicondyle in 17 patients. For 27 patients in whom the pain persisted after the injection, a combined Wilhelm and intraarticular procedure using the Bosworth or Boyd method was used. Degeneration of the orbicular ligament or a redundant synovial fold was reported in 77% of the intraarticular operation reports. At a follow-up examination, a minimum of two years and an average of four years nine months after surgery, 85% had good and excellent results after lateral and medial Wilhelm and 56% after combined surgeries while the poor results were 3% and 7% respectively. The results of combined surgery worsened from discharge to follow-up examination, and they show fewer good results than those where a sole Wilhelm procedure was performed. Therefore, intraarticular surgery should be considered for patients with incomplete pain relief after a test injection, but it should not routinely be performed.

From 1981 to 1986 we treated 413 patients for acute spinal-cord injuries. We reviewed 356 patients followed for a minimum of two years of whom 71 (20%) developed heterotopic ossification around one or more joints. Heterotopic ossification occurred more often in male patients (23%) than in female (10%), and was most frequent in the 20- to 30-year age group. It was also more common after injuries of the lower cervical or thoracic spine than after those of the lumbar spine. Patients with severe neurological deficits (Frankel grades A and B) showed significantly more heterotopic ossification but there was no correlation with the number or severity of associated head and limb injuries. Serum calcium levels did not change significantly in either group for 30 weeks after injury, but the erythrocyte sedimentation rate and the alkaline phosphatase level were significantly increased at six weeks in patients with heterotopic ossification.

In rats after nonstabilized femoral osteotomies, the changes in the release of prostaglandins (PGs) during bone healing (from bone and surrounding muscle tissue) were determined for PGE2, PGF2 alpha, 6-keto-PGF1 alpha, and thromboxane B2. A unilateral osteotomy, with contralateral soft-tissue dissection, was performed. After 4 or 10 days, the rats were killed and soft tissue and femoral bone were incubated, and the release of PGs was measured with specific radioimmunoassays. The release of PGs from rat femurs without previous surgery and from the sham-operated on side did not differ after 180 minutes' incubation. The release of PGE2, 6-keto-PGF1 alpha, and thromboxane-B2 from the osteotomy site was increased for bone on Day 4 and for muscle on Day 10 when compared with the controls. The release of PGF2 alpha from bone and muscle was about the same on both days, but increased as compared with the controls on Day 10 for bone. On Day 10, the other PGs for muscle and bone tissue were decreased as compared with Day 4. The most pronounced release of PGs occurred during the early healing phase after osteotomy; as early as 10 days after surgery, most of the PGs were not increased when compared with the sham-operated on side.

Synovial tissue from 37 patients suffering from osteoarthritis, chondrocalcinosis, active and inactive rheumatoid arthritis was investigated. The tissue was obtained during knee surgery and immediately incubated in tyrode solution. PGE2, 6-keto-PGF1 alpha, LTB4 and LTC4 were measured by radioimmunoassay. Calcium ionophore A 23187 stimulated the eicosanoid release significantly. This effect was more pronounced with LT than with PG. In the four different joint diseases there was no significant difference in the PG release. The LTC4 release was significantly lower in inactive rheumatoid arthritis as compared to the other joint diseases. For LTB4 this effect was significant only when compared to osteoarthritis. Indomethacin 10(-5) and 10(-7)mol/l inhibited the PG release from synovial tissue in all joint diseases significantly (p less than 0.05), there was no significant effect on the LT release. LT as well as PG are pro-inflammatory mediators. Non-steroidal anti-inflammatory drugs inhibit only the PG release. The remaining LT synthesis might thus be partially responsible for the lack of efficacy of these drugs in some patients.

The effect of equivalent mineral density on pedicular screw fixation strength was investigated. The equivalent mineral density of human vertebral bodies was correlated highly with the pullout force of Kluger screws (r2 = 0.61, P less than 0.02). A moderate to high correlation existed between density and vertical force (r2 = 0.42 for Kluger screws, r2 = 0.55 for Steffee screws, P less than 0.02). In calf vertebral bodies of higher density (146 +/- 14 mg/cc), the forces were significantly higher than in the human vertebral bodies (P less than 0.05). Human lumbosacral spines were instrumented with three different fixators: Steffee plates, AO fixateur interne, and Kluger fixateur interne. Of five specimens with a mean density of 88 +/- 11 mg/cc, one screw loosened. More than one screw loosened in six specimens with a mean density of 63 +/- 12 mg/cc, and no screw loosened in four specimens with a mean density of 114 +/- 38 mg/cc. Measurement of equivalent mineral density correlates with the fixation strength of the intrapedicular screws in vitro and should be considered in patients with signs of osteopenia before using pedicular screws for spinal fusions. It is also concluded that calf spines are a good model for testing implants because they tend to focus failure processes in the implant rather than in the implant-bone interface.

The in vitro effect of nucleus pulposus removal from human lumbar FSU's was investigated in a special test apparatus. Instability was determined by ROM, loss of disc height and displacement of the center of rotation. Disc height showed a decrease of 3.2 mm under axial load (700N). ROM increased up to 70%. The center of rotation demonstrated a distinct displacement in extension and lateral bending.

Poly-L-lactide (PLA) plates and screws were tested in vitro in porcine ribs for uniaxial pullout and four-point bending strength. Results were compared to conventional systems (stainless steel and titanium). The biomechanical testing suggests that PLA screws have properties suitable for fixation of sagittal split osteotomies. Poly-L-lactide plates have indications in areas of low stress and noncompressive load.

The physical and mechanical properties of calf lumbar and sacral trabecular bone were determined and compared with those of human trabecular bone. The mean tissue density (1.66 +/- 0.12 g cm-3), equivalent mineral density (169 +/- 36 mg cm-3), apparent density (453 +/- 89 mg cm-3), ash density (194 +/- 59 mg cm-3), ash content (0.6 +/- 0.05%), compressive strength (7.1 +/- 3.0 MPa) and compressive modulus (173 +/- 97 MPa) of calf trabecular bone are similar to those of young human. There were moderate, positive linear correlations between apparent density and equivalent mineral density, ash density, and compressive strength; and between compressive strength and equivalent mineral density (R2 ranging from 0.35 to 0.48, p less than 0.001). Apparent density, ash density, and equivalent mineral density did not differ significantly in different regions. In contrast to humans, the compressive strength increased from posterior, near the facet, to the anterior vertebral body. These comparisons of physical and mechanical properties, as well as anatomical comparisons by others, indicate that the calf spine is a good model of the young non-osteoporotic human spine and thus useful for the testing of spinal instrumentation.

Spinal cord lesions are not detectable on roentgenograms and computed tomography (CT) scans. Magnetic resonance images (MRIs) are able to make soft-tissue lesions visible. Interpretations of MRIs, CT scans, and roentgenograms were compared in 25 patients and three postmortem specimens with spinal cord injuries. In 14 patients and one specimen with normal roentgenograms and CT scans, the MRI demonstrated ten soft-tissue injuries as minimal displacement of the vertebral bodies or as a high signal intensity in the disc space, indicating a hematoma. Seven of the ten patients demonstrating soft-tissue injuries also had an intramedullary lesion, while in five of the 15 patients with normal CT scans, only a medullary lesion was present on MRI. In 11 patients and two postmortem specimens, fractures were seen on roentgenograms and CT scans. In these patients, the CT was superior to the MRI in detecting small bony fragments, but the medullary lesions were visible only on the MRIs. An intramedullary low signal intensity corresponded to macroscopically visible hemorrhages in the three postmortem specimens. The MRI provided important information in patients with neurologic deficits. No obvious pathologic changes were evident on the roentgenograms and CT scans. The MRI also demonstrated intramedullary and extramedullary soft-tissue lesions and was useful in establishing a diagnosis and in choosing appropriate therapy. CT, on the other hand, was superior in detecting small bony fragments and fracture lines.