Background and objective: The efficiency of intraoperative autotransfusion in scoliosis surgery is poorly known but needs to be evaluated, not least because of the large blood losses in these patients. This is a retrospective analysis of transfusion requirements of 43 such patients. Methods: Records from 43 patients were studied. During surgery, the shed blood was salvaged and washed in an autotransfusion device (AT1000 Auto-transfusion Unit«) and a suspension of red cells was reinfused. Results: Fifty-eight per cent of the intraoperative blood loss was salvaged. The total blood loss during the patients' hospital stay was calculated from the haemoglobin balance, 24% of this loss was salvaged by the device. Moreover, 36 of the patients needed allogeneic blood transfusion. Conclusion: The efficiency of the autotransfusion device was relatively low in relation to the total extravasation, mainly because the postoperative blood loss is substantial.

This study assessed the role of diagnostic arthroscopy following a wrist injury in patients with normal standard radiographs, an unclear clinical diagnosis and persistent severe pain at 4 to 12 weeks. Forty-three patients were included after conservative management had failed to improve their wrist pain so that a stability test could be performed satisfactorily and underwent arthroscopy within 12 weeks. Arthroscopy revealed recent pathology in 41 wrists, of which 17 had significant ligament lesions that might have benefited from acute repair. We conclude that patients with marked persistent post-traumatic symptoms despite conservative management are likely to have sustained ligament injuries despite normal radiographs. We therefore recommend that under these circumstances an arthroscopy is carried out within 4 weeks if the patient and surgeon wish to acutely repair significant ligament injuries.

[No abstract available]

Osteonecrosis of the jaw is a new disease, partly caused by bisphosphonates. It is commonly assumed that the bisphosphonates somehow cause cell death (osteocyte necrosis) within the jawbone, which makes it prone to chronic infection. In this article, an alternative pathogenetic theory is suggested, based on the normal effect of bisphosphonates. According to the new theory, the bone is alive until it is injured and infected, and the reduced resorptive ability due to bisphosphonates hinders the formation of a fresh bone surface for re-establishment of bone cell coverage. The theories are compared, based on the recent, very scarce literature. None of them can be completely refuted, but the demonstration of living osteocytes within the lesion and the number of necessary assumptions speak against the theory of a primary, bisphosphonate-induced necrosis.

Platelet concentrates have been implicated in bone and soft tissue repair for decades, but results from both preclinical and clinical studies have been meagre and conflicting. In a small animal model, a locally injected platelet concentrate accelerated the repair of injured Achilles tendons. This has raised a hope for clinical success in the treatment of tendon pathology. Treatment of tendinosis with platelet concentrates has been heavily marketed, and there is now an increasing public demand for this treatment. At a recent meeting in Linköping, Sweden, 2 ongoing randomised controlled studies were described, with some preliminary results. It was concluded that there is an increasing enthusiasm, but no useful clinical data.

This report is based on 1.851 adult patients with soft tissue sarcoma (STS) of the extremities or trunk wall diagnosed between 1986 and 1997 and reported from all tertiary referral centers in Norway and Sweden. The median age at diagnosis was 65 years and the male-to-female ratio was 1.1:1. One third of the tumors were subcutaneous, one third deep, intramuscular and one third deep, extramuscular. The median size was 7 (1-35) cm and 75% were high grade (III-IV). Metastases at presentation were diagnosed in 8% of the patients. Two thirds of STS patients were referred before surgery and the referral practices have improved during the study. The preoperative morphologic diagnosis was made with fine-needle aspiration cytology in 81%, core-needle biopsy in 9% and incisional biopsy in 10%. The frequency of amputations has decreased from 15% in 1986-88 to 9% in 1995-1997. A wide surgical margin was achieved in 77% of subcutaneous and 60% of deep-seated lesions. Overall, 24% of operated STS patients had adjuvant radiotherapy. The use of such therapy at sarcoma centers increased from 20% 1986-88 to 30% in 1995-97. Follow-up has been reported in 96% of the patients. The cumulative local recurrence rate was 0.20 at 5 years and 0.24 at 10 years. The 5-year metastasis-free survival rate was 0.70.

Tendons can function as springs and thereby preserve energy during cyclic loading. They might also have damping properties, which, hypothetically, could reduce risk of microinjuries due to fatigue at sites of local stress concentration within the tendon. At mechanical testing, damping will appear as hysteresis. How is damping influenced by training or disuse? Does training decrease hysteresis, thereby making the tendon a better spring, or increase hysteresis and thus improve damping? Seventy-eight female 10-wk-old Sprague-Dawley rats were randomized to three groups. Two groups had botulinum toxin injected into the calf muscles to unload the left Achilles tendon through muscle paralysis. One of these groups was given doxycycline, as a systemic matrix metalloproteinase inhibitor. The third group served as loaded controls. The Achilles tendons were harvested after 1 or 6 wk for biomechanical testing. An increase with time was seen in tendon dry weight, wet weight, water content, transverse area, length, stiffness, force at failure, and energy uptake in all three groups (P < 0.001 for each parameter). Disuse had no effect on these parameters. Creep was decreased with time in all groups. The only significant effect of disuse was on hysteresis (P = 0.004) and creep (P = 0.007), which both decreased with disuse compared with control, and on modulus, which was increased (P = 0.008). Normalized glycosaminoglycan content was unaffected by time and disuse. No effect of doxycycline was observed. The results suggest that in growing animals, the tendons continue to grow regardless of mechanical loading history, whereas maintenance of damping properties requires mechanical stimulation.

Post-traumatic osteoarthrosis develops after intraarticular injuries. It is a disease, which affects both articular cartilage and subchondral bone, and progresses over 10-20 years. Irreversible damage has often occurred by the time clinical diagnosis is possible. More knowledge about the early phase of the disease might yield measures to detect and delay or even prevent progression. This thesis evaluates changes in articular cartilage and subchondral bone at an early stage of post-traumatic osteoarthrosis.

Simultaneous changes in articular cartilage and subchondral bone were evaluated 3 to 40 weeks post-operatively in a rabbit meniscectomy model for post-traumatic osteoarthrosis. Rabbits were meniscectomized in the right knee and sham-operated in the left knee. Osteoarthrotic cartilage changes were evaluated by histology. Changes in the subchondral bone were evaluated by histology, scintimetry and dual-energy X-ray absorptiometry (DEXA). Joint space narrowing, and its utility as diagnostic tool at early stages of osteoarthrosis, was assessed with weight-bearing radiographs. The prognostic value of transforming growth factor-ßI (TGF-ß1) and proteoglycan fragment concentrations in the joint fluid at an early stage was also assessed.

We found slight cartilage changes and an increased metabolic activity in the subchondral bone as early as 3 weeks after meniscectomy. However, sham-operated knees displayed similar changes, although to a lesser degree. Cartilage fibrillation progressed at areas of high load within the meniscectomized knee joint. The subchondral bone showed a general response such as high scintimetric activity 3 weeks after surgery, and a decreased bone mineral density at later time points. Local adaptation in areas of high load within the subchondral bone was also seen. There was an increased osteoid content at the border between the cancellous bone and the marrow cavity already 3 weeks after meniscectomy, and at 13 weeks the subchondral bone plate was thickened. This thickening of the bone plate persisted up to 40 weeks. Joint space narrowing occurred after removal of the meniscus, but weight-bearing radiographs were not sensitive enough to measure early cartilage changes. Increased concentration of TGF-ß1 in the joint fluid at 3 weeks after surgery was associated with a higher degree of histological osteoarthrotic changes at a later time point.

Simultaneous changes in both cartilage and bone were apparent already 3 weeks after surgery, indicating that both tissues are involved from a very early stage. The localisation of cartilage changes illustrates that mechanical consequences of meniscectomy play a crucial role in progression of the disease. Surgical trauma resulted in increased release of TGF-ß1 at 3 weeks after surgery. This was found to be indicative for the severity of later osteoarthrosis. Thus, factors solely associated with the surgical trauma may also be important for the progression of osteoarthrosis.

Objective To assess changes in knee joint fluid concentrations of transforming growth factor-β1 (TGF-β1) and proteoglycan (PG) fragments during the early course of post-traumatic osteoarthrosis (OA) after meniscectomy in the rabbit knee, and to ascertain whether the concentrations of these substances shortly after operation could be used as prognostic markers for the OA process.

Design In 15 rabbits with medial meniscectomy in one knee and a sham operation in the other knee, synovial lavage fluid samples were taken repeatedly, before operation, every third week post-operatively until 12 weeks, thereafter every sixth week, and at death. Five rabbits each were killed at 13, 25 and 40 weeks. Synovial lavage fluid samples from five non-operated rabbits served as controls. At death, two histological scores were formed that characterized the highest (MAX) and the overall (ALL) degree of OA changes in each joint.

Results TGF-β1 and PG fragment concentrations in synovial lavage fluid correlated highly (R=0.81, P< 0.001). Both OA scores were higher in meniscectomized than controls (P< 0.05). The synovial lavage fluid concentration of TGF-β1 at 3 weeks, but no other time point, correlated to the histological scores (ALL, R=0.58; MAX, R=0.52;P< 0.001).

Conclusion Higher concentrations of TGF-β1 in synovial lavage fluid early after surgery seemed indicative for the later development of more severe OA changes in contrast to lower concentrations. The association between TGF-β1 and the changes found later in the cartilage was underlined by the high correlations between this substance and PG fragment concentrations in synovial lavage fluid at all time points.

We studied whether a small capsular incision alone, or combined with meniscectomy could induce early osteoarthritic changes in the rabbit knee. Thirty-one rabbits were operated on with a capsular incision in the left knee and meniscectomy in the right knee. Another 12 rabbits were used as controls. The rabbits were killed 3, 6 and 12 weeks after surgery. Osteoarthritic changes in the articular cartilage were evaluated by the modified Mankin score. The subchondral bone was evaluated by scintimetry (99mTc-HDP) and semiquantitative grading of histological changes. Osteogenic protein (OP-1) in its mature and pro-form was examined by immunohistochemistry. Both a capsular incision and meniscectomy induced articular cartilage fibrillation and increased bone metabolic activity during the initial weeks after surgery. Capsular incision led to lesser changes than meniscectomy. Mature OP-1 was elevated, and its pro-form reduced, in meniscectomized knees. A similar pattern was observed in knees with capsular incision. Already 3 weeks after surgery, the articular cartilage and subchondral bone showed typical signs of early osteoarthritis (OA), and a reparative response was suggested by increased intensity of OP-1 staining. As these signs were also found in knees with capsular incision only, it appears that trauma-related factors such as increased bleeding and inflammation are critical for the development of OA. Copyright © Blackwell Munksgaard 2006.

Increased knowledge about the early cartilaginous and osseous responses to meniscectomy may elucidate processes behind development of osteoarthrosis. The purpose of the present study was to evaluate tibial bone and cartilage changes during the first months after meniscectomy.

Thirty-one skeletally mature New Zealand white rabbits were operated on with meniscectomy in the right knee and a sham-operation in the left knee. Another 12 rabbits were used as controls. The knee joints were evaluated 3, 6 and 12 weeks after surgery by radiolabelled bisphosphonate uptake (^99mTc-HDP) and semiquantitative grading of histological changes in the subchondral bone and cartilage.

Already 3 weeks after meniscectomy, there was increased metabolic activity in the subchondral bone, and articular cartilage fibrillation. Similar changes were seen in shamoperated knees, but to a lesser extent. This appears to be caused both by the new loading situation in the joint after meniscectomy and the operative trauma.

We evaluated morphological changes in the tibial bone after meniscectomy in a rabbit model. 15 rabbits subjected to a medial meniscectomy in the right knee and a sham-operation in the left. Histomorphometric parameters were evaluated in the subchondral bone plate and the underlying trabecular bone, 13, 25 and 40 weeks after surgery. 5 rabbits were used as unoperated controls.Meniscectomized knees had a thicker subchondral bone plate than sham-operated contralateral ones in 13 of the 15 rabbits (p= 0.01), but the trabecular bone showed no morphological differences. The meniscectomized knees of these rabbits developed mild osteoarthrosis, described elsewhere, which may have been partly due to a change in the mechanical properties of the thickened subchondral bone plate. Our findings suggest that the first bony response after meniscectomy occurs in the subchondral bone plate rather than in the trabecular bone.

Cartilage derived morphogenetic proteins (CDMPs, also known as growth and differentiation factors, GDFs) are a subgroup of the bone morphogenetic protein (BMP) gene family. As most BMPs, they are known to induce cartilage or bone formation when implanted subcutaneously or intramuscularly on an appropriate carrier. However, similar implantation experiments with CDMPs have also reported the formation of a tendon-like tissue, without any cartilage or bone. A solution to this apparent contradiction might be offered by the mechanical tissue differentiation theory, suggesting that tissue differentiation depends on the mechanical environment. This study analyzes the response to CDMP-2 implants at different sites and under different loading conditions in the rat. Collagen sponges carrying CDMP-2 were implanted subcutaneously, intramuscularly or inside a freshly created defect in the achilles tendon. Large amounts of bone were induced subcutaneously, smaller amounts intramuscularly, and in the tendons, only small amounts of bone or cartilage were seen in few animals. Thus, the amount of bone appeared inversely related to the degree of mechanical stimulus. To confirm this, CDMP was also injected into tendon defects that were either loaded or partially unloaded. All the unloaded tendons showed bone induction after one CDMP-2 injection, whereas only 4 of 10 loaded ones showed any cartilage or bone (p = 0.0005). Single injections of a similar dose of CDMP-2 have previously been shown to augment tendon repair by increasing the size of the tendon callus. This study suggests that the response to CDMP-2 is dependent on the mechanical situation at the site where it is applied. ⌐ 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Background: Achilles tendon ruptures in humans might be treated more efficiently with the help of a growth factor. Cartilage-derived morphogenetic protein-2 has been shown to induce formation of tendon-like tissue. Hypothesis: Cartilage-derived morphogenetic protein-2 has a positive effect on mechanical parameters for tendon healing in a rabbit model with Achilles tendon transection. Study Design: Controlled laboratory study. Methods: The right Achilles tendon of 40 rabbits was transected without tendon suture. Cartilage-derived morphogenetic protein-2 (10 ╡g) or vehicle control (acetate buffer) was injected locally 2 hours postoperatively. All tendons were tested biomechanically at 8 and 14 days, and treated tendons were histologically and radiographically evaluated at 56 days. Results: At 14 days, both failure load and stiffness of treated tendons were increased by 35%. The treated tendons had significantly larger callus size at 8 and 14 days. Histologic and radiographic examination showed no signs of ossification in the treated tendons after 56 days. Conclusions: A single injection of cartilage-derived morphogenetic protein-2 led to a stronger and stiffer tendon callus than that in the controls without inducing bone formation. Clinical Relevance: Similar results from a larger animal model would suggest a possible future use of cartilage-derived morphogenetic protein-2 in the treatment of human Achilles tendon ruptures. ⌐ 2003 American Orthopaedic Society for Sports Medicine.

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the formation of bone. However, they have been shown to increase tensile strength in healing tendons. Most NSAIDs inhibit two isoforms of cyclooxygenases called Cox-1 and Cox-2. Thanks to fewer side-effects, the recently introduced selective cyclooxygenase-2 (Cox-2) inhibitors will probably promote more widespread use of this kind of drug. To clarify the effects on tendon healing of a general Cox-inhibitor (indomethacin) as well as a selective Cox-2 inhibitor (celecoxib), we resected 3 mm of the Achilles tendon in rats and measured the strength of the tendon regenerate. Indomethacin given as daily injections in doses of 1.5, 3.0 and 5.0 mg/kg reduced the thickness (cross-sectional area) of the tendon regenerate at 14 days, as compared to controls, but there was no difference in the failure load or stiffness. In another series of measurements, indomethacin in a dose of 3.0 mg/kg reduced the cross-sectional area at 10, 14 and 18 days after transsection. Failure load was not affected, but tensile stress at failure was increased by indomethacin at 14 and 18 days. Indomethacin (3 mg/kg) was then compared to celecoxib (4.5 mg/kg) and controls 14 days after tendon transsection. No difference between the drugs was seen. Again, the transverse area was smaller in the treated tendons than in the controls. Failure load was unchanged and the tensile stress was higher in the treated tendons than in the controls. Because of the reduction in cross-sectional area without an effect on failure load, the use of Cox-inhibitors may be beneficial in clinical situations where thickening of a healing tendon is a problem - e.g., in the hand or shoulder.

Cartilage-derived morphogenetic proteins (CDMPs), belonging to the bone morphogenetic protein (BMP) family, are known to b cartilage and bone inducers as well as to induce tendon and ligament-like tissue. In this study we investigated the influence of CDMP-1, -2 or -3 at four different doses (0, 0.4, 2 and 10 ?g) on tendon healing in a rat model, as well as differences in osteogenesis between the different CDMPs and doses. In 110 rats, a 3 mm segment of the Achilles tendon was removed via a 2 mm skin incision. CDMP-1, -2 or -3 was injected into the defect 6 h postoperative. The rats were killed 8 days after operation. The tendon regenerates were tested biomechanically. There was a significant dose-related increase in strength and stiffness with all three CDMPs, but no difference between the CDMPs was found. Another 50 rats were used to compare the highest dose of the CDMPs with controls and osteogenic protein 1 (OP-1), as regards cartilage or bone formation after 4 weeks. Cartilage occurred in all groups, including the controls. Some specimens in all groups contained bone, except the controls. No difference between the CDMPs could be demonstrated. The CDMP-1, CDMP-3 and OP-1 groups contained significantly more calcium than controls. Only the CDMP-2 group and the controls contained significantly less calcium than the OP-1 group. In conclusion, the three CDMPs appeared similar as regards improvement of tendon repair and osteogenicity in this setting. ⌐ 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

This study evaluates the effect of rhBMP-7/OP-1 on the osseointegration of commercially pure titanium implants in an experimental implant model in rabbits. Threaded titanium implants with two transverse parallel canals were inserted in the femur and tibia of rabbits. The canals were filled with, 10 ╡g of BMP-7/collagen carrier, pure collagen carrier or were left empty as a control. The stiffness of the implant fixation was evaluated by Resonance Frequency Analysis (RFA) at baseline and four weeks postoperativly. Percentage of bone ingrowth in the canals was measured on microradiographs. Histomorphometry along the threaded part of the implants was performed on 15 ╡m thin sections. The results from the RFA demonstrated a higher mean value for the BMP-7 treated implants in the tibia than the carrier treated implants but not compared to the control implants. The control implants in the tibia demonstrated more bone ingrowth in the upper canal than to the carrier or the BMP-7 treated implants. Apart from these differences there were no significant effects of BMP. In this study BMP-7 did not contribute to any substantially improved bone anchorage of titanium implants.

The medial meniscus of the rabbit knee joint attaches to the tibial plateau via anterior and posterior insertions. Intact meniscal tibial insertions are essential for meniscal function. In the present study the distributions of types I, II, and X collagen in meniscal tibial insertions were investigated by indirect immunohistochemistry in a rabbit model. Four tissue zones were histologically identified in the anterior insertion site, including the ligamentous zone, uncalcified and calcified fibrocartilaginous zones and bone, the ligamentous zone was not observed in the posterior insertion site. Labeling for type I collagen was found to be strong in the ligament tissue and bone, and weak in the fibrocartilages which were also labeled for type II collagen. Tissues positive for different types of collagen overlapped and formed an irregular interface with various angles and depths, especially at the interface between the calcified fibrocartilage and bone. Positive labeling for type X collagen was identified only in the calcified fibrocartilage zone. The coexistence of types I and II collagen in the meniscal tibial insertions may indicate that this structural unit is subjected to both compressive and tensile loads. Type X collagen may play a role in maintaining the calcifying status of this tissue zone, so that its mechanical stiffness is kept between that of uncalcified fibrocartilage and hard bone. Restoration of the insertional structure including the distinct collagen distribution should be considered for a functional meniscal substitution.

Meniscal injuries are common in sports. Surgical removal of the meniscus to relieve symptoms is associated with a high risk for late knee joint osteoarthrosis and pain. Meniscal repair or replacement has therefore been advocated. In meniscal replacement procedures proper fixation of the substitute to bone is decisive to guarantee normal meniscal load transmitting function and prevention of osteoarthrosis. Secure fixation of the graft is also essential for the success of ligament reconstruction. Thus, this thesis concentrates on exploration of normal morphology of the insertions of the medial meniscus and other knee ligaments, their ultimate strength and failure mode, and finally the capacity of the meniscal insertion for repair and reconstruction in a rabbit animal model.

Extreme mechanical demands are posed on the insertion which connects highly loaded and mobile ligamentous tissue to bone. The abrupt change in tissue stiffness in the insertion is made more gradual by interposition of uncalcified and calcified fibrocartilage tissues of intermediate stiffness between the soft ligament and the hard bone. The thickness of calcified fibrocartilage in an insertion seems to be related to the amount of bending at this site. The interface between calcified fibrocartilage and bone is irregular thereby increasing the contact area between these 2 mechanically different tissues and their resistance to separation; its configuration is individual in each ligament and seems adapted to the loads to which the insertion is subjected. During mechanical testing failures through insertional structures were rare, which confirmed the effectiveness of this tissue configuration. Presence of nerve fibres in meniscal insertional structures suggests sensory function beside the mechanical ones. Hence, all of these specific features need to be reestablished after a reconstructive procedure to ensure adequate insertional function.

Transection of meniscal insertions without refixation resulted in repair which after 12 weeks showed tissue differentiation and maturation according to local loading conditions. The repair tissue in the anterior insertion which is mainly loaded in tension acquired ligament-like appearance; in the posterior insertion, which is subjected to compressive, shear and tensile loading, fibrocartilage-like tissue had formed. Calcified and uncalcified fibrocartilages mimicing insertional tissue formed after refixation of the insertion into a bone channel, but a nonnal collagen matrix, interface to bone and mechanical strength did not reestablish.

A meniscal insertion healed in prolongated position after transection, and in a case with refixation, it was found partially pulled out. This resulted in both instances in a displacement of the meniscus to the joint periphery and signs for osteoarthrosis similar to what has been found after removal of the meniscus. Thus, despite some capacity of the repair tissue to differenciate and mature to insertionspecific tissue after transection or reconstruction a normal load transmission function of the meniscus probably did not reestablish, and osteoarthrosis was common. Further studies are necessary to improve the fixation of meniscal or ligament substitutes to bone.

This study, comprising 7 separate papers, is concerned with the additional information supplied by a kinesiological approach for evaluation of patients with instability due to old ligamenta us injury to the knee or ankle joint. This approach required development of new methods for kinesiological analysis.

Impaired performance in patients with old anterior cruciate ligament (ACL) rupture was mainly found in tests which greatly stress the knee joint, ie figure-of-eight running and one-legged jump for distance.

A scaling model approach was constructed and found appropriate in evaluating knee and ankle function in patients with ligarnentous injuries.

A dynamic, two-dimensional, biomechanical model was developed and implemented in a motion analysis system together with a force plate and EMG. This model was found useful for evaluation of kinematics, kinetics and muscular activation patterns at the ankle, knee and hip joints during functional movements such as walking and jumping.

A movement analysis could reveal adapted movement- and muscular activation patterns for the ACL-deficient knee compared to the noninjured at touch down at one-legged jump. An internal knee model disclosed a simultaneous decrease in sagittal shear load which was interpreted as an adaptation to avoid increased intrinsic joint movements or gross subluxations.

Unilateral injury to the lateral ligaments of the ankle is related to both ipsi- and contralateral functional alterations. There is a risk of underestimating the impairment of the injured joint in a function test using the noninjured side as a reference.

A perturbation device was construcred and found useful for the analysis of postural strategies, reaction latencies and ankle joint function during single limb stance. The ankle joints were found to be of primary concern for postural corrections to retain equilibrium in single limb stance.

A quasi static, three-dimensional ankle model was developed and implemented in a motion analysis system which made possible study of ankle joint function, load and instability. Different motor patterns were found for the functionally unstable foot compared to the stable in single limb stance.

Osteoporosis increases fracture risk, especially in metaphyseal bone. Fractures seriously impair function and quality of life and incur large direct and indirect costs. Although the prevention of fractures is certainly the option, a fast and uneventful healing process is optimal when fractures do occur. Many new therapeutic strategies have been developed to accelerate fracture-healing or to diminish the complication rate during the course of fracture-healing. However, widely accepted guidelines are needed to demonstrate the positive or negative interactions of bioactive substances, drugs, and other agents that are being used to promote fracture-healing. For each study design, the primary study goal should be indicated. Outcome variables should include both objective and subjective parameters. The guidelines should be harmonized between European and American regulatory authorities to ensure comparability of results of studies and to foster global harmonization of regulatory requirements.

This study, comprising 7 separate papers, is concerned with the mechanical causes of graft failure after intraarticular reconstruction of the anterior cruciate ligament (ACL). The study is predominantly experimental in design, but a clinical follow-up is also included to test a causal hypothesis of secondary graft elongation.

Fixations of synthetic ACL substitutes with ligament staples had low security and the maximum tolerance loads were in parity with forces generated during daily activities, while screw fixations of looped ligaments had higher load to failure than a normal ACL.

A stenosis, caused by osteophyte formation, was found at the intercondylar notch less than 2 years after an ACL tear, strongly suggesting impingement and wear as a possible mechanism of ACL substitute failure. The intercondylar notch was also found to be narrowed in patients with an acute tear of the ACL compared to a normal control group, thus implying causality.

A standardized technique of graft placement, using a guide to aid bone drilling, was found more accurate and reproducible in achieving desired graft insertions compared to freehand drilling. This was evaluated by a new method for detennining the graft insertion locations on the femur and tibia, using a ratio related to the sagittal depth of the condyles.

The ability to restore knee kinematics from an ACL deficient state, was evaluated for a drill guided graft route and an over-the-top route. The only effect of both methods, using a dacron graft tensioned in full extension, was restoring or partially restoring the increased anterior -posterior translation.

A good in vitro and in vivo correlation was found between the patterns of change in dynamic fixation distance, as measured intraoperatively with an isometer, and tension in the fixed ACL substitute. The isometry measurement could not predict the magnitude of the frnal tension due to the biological variability in soft tissue compliance.

Sagittal knee stability was measured at regular intervals for 2 years on patients who had an intraarticular ACL reconstruction with a patellar tendon substitute. Increasing anterior-posterior displacement was found for all patients as a group, and more for patients with an anterior femoralligament insertion location.

A standardized treatment including aided bone drilling, notch plasty, isometry measurement, and restricted postoperative rehabilitation is recommended.

Background. Total knee arthroplasty (TKA) is often carried out using a tourniquet and shed blood is collected in drains. Tranexamic acid decreases the external blood loss. Some blood loss may be concealed, and the overall effect of tranexamic acid on the haemoglobin (Hb) balance is not known. Methods. Patients with osteoarthrosis had unilateral cemented TKA using spinal anaesthesia. In a double-blind fashion, they received either placebo (n=24) or tranexamic acid 10 mg kg-1 (n=27) i.v. just before tourniquet release and 3 h later. The decrease in circulating Hb on the fifth day after surgery, after correction for Hb transfused, was used to calculate the loss of Hb in grams. This value was then expressed as ml of blood loss. Results. The groups had similar characteristics. The median volume of drainage fluid after placebo was 845 (interquartile range 523-990) ml and after tranexamic acid was 385 (331-586) ml (P<0.001). Placebo patients received 2 (0-2) units and tranexamic acid patients 0 (0-0) units of packed red cells (P<0.001). The estimated blood loss was 1426 (1135-1977) ml and 1045 (792-1292) ml, respectively (P<0.001). The hidden loss of blood (calculated as loss minus drainage volume) was 618 (330-1347) ml and 524 (330-9620) ml, respectively (P=0.41). Two patients in each group developed deep vein thrombosis. Conclusions. Tranexamic acid decreased total blood loss by nearly 30%, drainage volume by ~50% and drastically reduced transfusion. However, concealed loss was only marginally influenced by tranexamic acid and was at least as large as the drainage volume.

Objective: To estimate the impact of osteoporosis fractures on health-related quality of life (HRQOL) in postmenopausal women. Methods: To compare the impact on HRQOL of different osteoporotic fractures, 600 consecutive women 55-75 years old with a new fracture (inclusion fracture) were invited by mail. After exclusions by preset criteria (high-energy fractures, ongoing osteoporosis treatment, or unwillingness to participate), 303 women were included, 171 (56%) of whom had a forearm, 37 (12%) proximal humerus, 40 (13%) hip, and 55 (18%) vertebral fracture, respectively, and all were investigated and treated according to the current local consensus program for osteoporosis. In addition, HRQOL was evaluated by the SF-36 questionnaire and compared with local, age-matched reference material. Examinations were performed 82 days (median) after the fracture and 2 years later. Results: HRQOL was significantly reduced at baseline regarding all SF-36 domains after vertebral fractures and most after hip fractures, but only regarding some domains after forearm and humerus fracture. After 2 years, improvements had occurred after all types of fractures, and after forearm or humerus fracture, HRQOL was completely normalized in all domains. However, 2 years after hip fracture, HRQOL was still below normal regarding physical function, role-physical and social function, while after vertebral fracture, scores were still significantly lower for all domains, physical as well as mental. Patients with one or more previous fractures before the inclusion fracture had lower HRQOL at baseline and after 2 years, compared with those with no previous fracture. Patients with osteoporosis (T-score < - 2.5 in hip or spine) had lower HRQOL than those with normal BMD. Conclusion: Vertebral and hip fractures have a considerably greater and more prolonged impact on HRQOL than forearm and humerus fractures. The number of fractures was inversely correlated to HRQOL. These differences should be taken into account when making priorities in health care programs.

A major concern in using growth factors in impaction grafting is the potential stimulation of the osteoclastic lineage. A solution would be using an osteoconductive material resistant to resorption and providing initial stability after reconstruction. Growth factors may promote bone formation in combination with such graft materials. We determined whether OP-1 would promote the incorporation of impacted morselized allografts and tricalcium phosphate/hydroxyapatite (TCP/HA) into host bone, whether bone formation would be preceded by an initial process of accelerated resorption, and whether the response to OP-1 remodeling/incorporation would be dose-related. We performed two bone chamber studies in goats to ascertain the early effects of OP-1 dose on resorption and incorporation of impacted morselized allografts and TCP/HA. After 4 weeks, the incorporation process of impacted morselized allografts and TCP/HA was not promoted by OP-1. We observed no signs of accelerated resorption preceding bone formation. An increase in OP-1 dose resulted in an inhibition of fibrous tissue formation but OP-1 did not promote bone formation. Early failures in impaction grafting, using mixes with OP-1, might be explained by the lack of fibrous tissue ingrowth and not by increased resorption and remodeling. © 2006 Lippincott Williams & Wilkins, Inc.

In the bone conduction chamber (BCC) various materials and factors have been tested for their effect on bone graft incorporation and bone healing. However, biomaterials often have to be crushed to fit in this small chamber. Since cellular responses to biomaterials are influenced by the size and shape of particles, research concerning the evaluation of biomaterials is limited by the dimensions of this bone chamber. We enlarged and modified the BCC in order to be able to investigate the in vivo influences of biomaterials, growth factors and bone graft processing on tissue and bone ingrowth. Seven goats received four bone chambers each, three modified models and a BCC. The first model (BCC+) had two ingrowth openings, similar to that of the BCC. The second model had two round ingrowth openings (ROU). The third model had a open bottom for bone ingrowth (BOT). After 12 weeks, bone ingrowth distances were measured on histological sections and using μCT. Bone ingrowth was significantly higher (p=0.009 and 0.008) in the ROU compared to the BCC+ and the BOT, respectively. Similar results were found using μCT. The ROU model performed most similar to the BCC (gold standard) and is considered to be a promising new tool in biomaterials research. © 2005 Elsevier Ltd. All rights reserved.

The purpose of this prospective and randomized study was to compare rehabilitation with early range of motion (ROM) training vs immobilization following anterior cruciate ligament (ACL) reconstruction. Fifty patients, undergoing an ACL reconstruction with a bone-patellar tendon-bone graft, were postoperatively allocated randomly to either a plaster cast or a brace for 5 weeks. The brace group had ROM exercises from post-operative day 7. The commencement of ROM exercises was postponed 4 weeks for the plaster group compared to the brace group, but progressed subsequently with equal speed. There was no difference between the groups in the ROM of flexion or extension 20 weeks after the ACL reconstruction and later. Twenty-four months after surgery, the muscle strength deficit in the hamstring muscles (isokinetic measurements, percent difference, injured vs uninjured) was significantly larger in the brace group (mean +/- SD: 5.9 +/- 7.8%, P < 0.01) than in the plaster group (-0.9 +/- 11.8%, NS) (brace vs plaster group, P <0.05). Furthermore, there was also a tendency in the brace group to a larger strength deficit in the quadriceps muscle (brace: 11.1 +/- 13.2%, P <0.001, plaster: 3.8 +/- 12.9%, NS) (brace vs plaster group, P = 0.07). There was no difference between the groups in the total sagittal knee laxity, as measured with an arthrometer, or in the subjective knee function or activity level (Lysholm score together with the Tegner activity level) between the groups. It is concluded that the postoperative treatment with early range of motion training after ACL reconstruction gave as good ROM, knee stability, subjective knee function and activity level as the treatment with immobilization. It is hypothesized that the larger strength deficit observed after rehabilitation with early range of motion training is secondary to the more intensive training and physical therapist involvement that was demanded in order to achieve full ROM following immobilization.

Background: We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year, as measured by radiostereometry (RSA). We now report the 4-year results. Methods: This was a double-blind randomized study, using RSA with maximal total point motion (MTPM). Results: With analysis according to the "intention to treat" principle, the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis (a secondary variable) in the clodronate group. However, 3 patients (all clodronate) did not take any tablet after surgery. If they are excluded, there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline, with the clodronate group showing 25% less migration. From 1 to 4 years, there was no difference in migration rate by MTPM, but there was a continuous increase in rotation around the transverse axis in the controls, which differed from the clodronate group. There were no cases of aseptic loosening. 2 patients had migration of more than 1.3 mm from baseline to 4 years, neither of them had taken clodronate. The others had migration of less than 0.9 mm. Interpretation: Because migration was clearly reduced by clodronate during the first postoperative year, and there was still a difference at 4 years when analyzed per protocol, it appears likely that this treatment can diminish the risk of loosening. The difference in the number of outliers also points in this direction, and may be more relevant than mean migration values. Copyright© Taylor & Francis 2006.

This study, comprising 7 separate papers, is concerned with treatment of medial gonarthrosis.

Results after high tibial osteotomy were found to deteriorate 8-9 years after surgery. The best results were seen in knees with preoperative Stage I or II osteoarthrosis and valgus deviation after osteotomy.

The rehabilitation period after high tibial osteotomy is long, recovery of the average thigh muscle torque was first seen after 12 months. Stable internal fixation with early mobilization does not seem to be advantageous in this respect.

Gait analysis showed signs of insufficient rehabilitation persisting 8-12 months after high tibial osteotomy, with unimproved maximum gait velocity and reduced stride length at constant maximum velocity.

Rehabilitation with restitution of muscle torque was faster after unicompartmental arthroplasty and gait parameters did improve.

An "anatomical" type of unicompartmental prosthesis seems to be more susceptible to load, with changed strain elicited in external rotationcompared to a meniscus bearing prosthesis.

Knees with medial osteoarthrosis showed less rotation clinically duringmotion than healthy knees. The rotation was not significantly affected by a unicompartmental arthroplasty.

A radiographic method for detection of prosthetic migration, using tantalum balls implanted in the skeleton, was developed and tested on 20 patients.

OP-1 increases bone ingrowth distance of new bone into allografts (TΣgil et al. 2000), but the bone density after incorporation may be reduced by an increase in resorption (H÷stner et al. 2000). Bisphosphonates inactivate osteoclasts and can be used to increase allograft bone density after incorporation (Aspenberg and ┼strand 2002). A combination of locally-applied bisphosphonate and OP-1 in the graft could therefore be expected to increase both new bone ingrowth and density. We tested this by using a rat bone chamber model. OP-1 alone increased the ingrowth distance of bone. Clodronate increased final bone density greatly, but reduced the ingrowth distance of new bone into grafts that were extremely impacted. This reduction was improved by adding OP-1. Regardless of graft density, combinations of OP-1 and clodronate included a high final bone density, but the ingrowth distances were shorter than with OP-1 alone. These data indicate that new bone and tissue ingrowth into a compacted graft depends on resorption and that resorption is a prerequisite for the stimulating effect of OP-1 in this experimental set-up. Although the problems associated with the use of OP-1 in impaction grafting may be solved by adding a bisphosphonate, some of the benefits of OP-1 can be lost.

Study Design. Randomized efficacy trial comparing two types of noninstrumented posterolateral fusion between L5 and S1 in patients with L5 spondylolysis and vertebral slip less than 50%, as evaluated by radiostereometric analysis. Objective. To determine whether osteogenic protein-1 (BMP-7) in the OP-1 Implant yields better stabilizing bony fusion than autograft bone. Summary of Background Data. Animal studies of osteoinductive proteins in noninstrumented posterolateral fusions have shown high fusion rates. No similar conclusive study on humans has been performed. Methods. For this study, 20 patients were randomized to fusion with either OP-1 Implant or autograft bone from the iliac crest, 10 in each group. The patients were instructed to keep the trunk straight for 5 months after surgery with the aid of a soft lumbar brace. At surgery 0.8-mm metallic markers were positioned in L5 and the sacrum, enabling radiostereometric follow-up analysis during 1 year. The three-dimensional vertebral movements, as measured by radiostereometric analysis induced by positional change from supine posture to standing and sitting, were calculated with an accuracy of 0.5 to 0.7 mm and 0.5░ to 2.0░. Conventional radiography was added. Results. No significant difference was noted between the radiostereometric and radiographic results of fusion with the OP-1 Implant and fusion with autograft bone. There was a significant relation between reduced vertebral movements and better bone formation. No adverse effects of the OP-1 Implant occurred. Persistent minor pain at the iliac crest was noticed in one patient. Conclusions. There was no significant difference between the two fusion versions. Thus, the OP-1 Implant did not yield better stabilizing bony fusion than autograft bone.