Lateral and Posterior Approaches in Hemiarthroplasty.

PURPOSE: Hemiarthroplasty is a common treatment for patient with a fragility displaced femoral neck fracture. We compared lateral and posterior approaches with respect to need for mobility aids, mobility level, living arrangements, pain, hip dislocation, and survival 12 months after hip fracture. METHODS: A total of 393 fragility femoral neck fracture patients aged 65 years or more who underwent hemiarthroplasty were observed for 12 months. Patient information was collected on admission, during hospitalization, and by telephone interview 1 year after the hip fracture. A total of 269 patients were included in the final analysis. RESULTS: At 1 year after hip fracture, more patients undergoing hemiarthroplasty with the posterior approach (22%) survived without mobility aids compared to those with the lateral approach (12%; p = 0.026). Multivariate logistic regression analysis revealed that the need for mobility aids 1 year after hip fracture was significantly predicted by the use of mobility aids before the fracture (odds ratio = 13.46, 95% confidence interval = 4.29-42.25), age ≥85 years (odds ratio = 3.85, 95% confidence interval = 1.09-13.44), male sex (odds ratio = 3.59, 95% confidence interval = 1.05-12.22), and lateral approach (odds ratio 2.73, 95% confidence interval 1.15-6.50). The posterior approach resulted in four (3.4%) dislocated hips, compared with none by the lateral approach. Survival, mobility level, pain in the operated hip, and living arrangements 1 year postoperatively were not significantly different between groups. CONCLUSION: Hemiarthroplasty using a lateral approach predisposed to the need for ambulatory aids 1 year after hip fracture. The posterior approach, however, predisposed to hip dislocation. Patient selection must be considered when deciding the appropriate surgical approach.

Knee injuries related to sports in young adult males during military service - incidence and risk factors.

The population-based incidence and risk factors for knee injuries in young adults were assessed in Finnish male conscripts performing their compulsory military service (n = 128,584). The main outcome variables were (1) hospitalization due to knee injuries overall and (2) hospitalization due to knee disorders as categorized into specific International Classification of Diseases, tenth revision diagnoses (cruciate and collateral ligament tears, meniscal tears, traumatic chondral lesions, and patellar dislocations). Person-time injury-incidence rates were calculated by dividing the number of persons with a diagnosed knee injury by the total exposure time of 97,503 person-years. The number of subjects with surgical operations and military service class changes indicative of longer term notable disability are also reported. Risk factor analyses were performed by logistic regression. The person-based incidence of hospitalizations for knee injury was 11 cases per 1000 person-years [95% confidence interval (CI): 10.4-11.7]. The most important risk factors were higher age (odds ratio 1.7; 95% CI: 1.3-2.2) and obesity (odds ratio 1.6; 95% CI: 1.03-2.5). Two thirds of all subjects hospitalized for knee injuries had surgery, and one third had longer term notable disability. These findings indicate that knee injuries cause a significant burden of hospitalizations, often leading to surgery and longer term disability.

Can elevated serum TRACP-5b levels predict stress fractures? A cohort study.

BACKGROUND AND AIMS: Stress fracture is a common overuse injury in athletes and military conscripts. The reliable diagnosis of stress fractures is often difficult, however, because it is usually based solely on radiographic findings. Biochemical markers of bone resorption reflect bone degradation and may also reflect the rate of bone loss. The aim of the study was to examine whether elevated serum tartrate-resistant acid phosphatase isoform 5b (TRACP-5b) levels reflect enhanced bone remodeling and predict the occurrence of stress fractures in military conscripts. MATERIAL AND METHODS: Randomly selected military conscripts [mean age, 19.8 (range 18-28) years; n = 820] were followed for 3 months. Baseline blood samples were drawn upon arrival to the service. Four subsequent samples were obtained from subjects that developed stress fractures and one sample each was obtained from two asymptomatic control subjects for each fracture case. RESULTS: Plain radiography was used to diagnose stress fractures in 20 of the 820 conscripts (2.4%). Follow-up data were available for 14 subjects with 21 stress fractures and 28 control subjects. Subjects with proportionally increasing serum TRACP-5b levels had an 8-fold greater probability of stress fracture than controls. No statistically significant difference was detected. CONCLUSIONS: Although assessing serum TRACP-5b levels appears to be a promising method to predict bone stress injuries, the present study failed to give a conclusive statement of its usefulness as a diagnostic tool.

Long-term outcome of a transglenoid suture technique for anterior shoulder instability in young adults.

We reviewed the outcome of arthroscopic stabilisation of anterior glenohumeral instability in young adults using the transglenoid suture technique. A questionnaire was sent to 455 consecutive patients who had undergone this procedure between 1992 and 2000. Of these, 312 patients (68.5%) with 313 affected shoulders and a mean age of 20 years (18 to 28) responded. Outcome was determined by the number of re-dislocations or, in patients who had not re-dislocated, by the disease-specific quality of life as measured by the Western Ontario Shoulder Instability index. During a mean follow-up of 6.4 years (1 to 14), 177 patients (56%) sustained a re-dislocation, including 70 who required a further operation. In 136 patients (44%) who reported neither re-dislocation nor re-operation, the index scores were good (median 90.4%; 28.9% to 100%). No significant peri- or pre-operative predictors of re-dislocation or re-operation were found. We found a high rate of re-dislocation after transglenoid suture repair in young, physically active patients.

Elongated patellae at the final stage of Osgood-Schlatter disease: a radiographic study.

Aetiology of Osgood-Schlatter disease (OSD) is still unknown. Relative length of the patellar articular surface with the length of the patella, relative height of the tibial tubercle with the sagittal diameter of the tibia, Insall-Salvati, Blackburne-Peel, and Caton-Deschamps indexes, as well as Grelsamer-morphology type of the patella were measured from preoperative plain X-rays in 82 knees of 20-year-old males with OSD and in 87 knees of 20-year-old male controls with normal MRI findings of the knee. Seventy-eight of the OSD patients had separate ossicles. Their mean patellar morphology index was 1.44 and that of the controls was 1.28 (p<0.001), indicating significant lengthening of the patellar body among the OSD group. OSD patients had also significantly more often Grelsamer type II (elongated patellae) than the controls. Tibial tuberosity was significantly higher among OSD patients, but was not correlated with the lengthening of the patella. An increased patellar height among OSD patients was shown by the Blackburne-Peel and Caton-Deschamps indexes (p<0.001) and the Insall-Salvati index (p=0.018). OSD patients exhibit elongated patellae and patellar tendons which may result from long-standing tension of the extensor apparatus during growth spurt, when femoral growth exceeds that of the anterior structures of the knee.

Long-term outcome of undisplaced fatigue fractures of the femoral neck in young male adults.

The incidence and long-term outcome of undisplaced fatigue fractures of the femoral neck treated conservatively were examined in Finnish military conscripts between 1970 and 1990. From 106 cases identified, 66 patients with 70 fractures were followed for a mean of 18.3 years (11 to 32). The original medical records and radiographs were studied and physical and radiological follow-up data analysed for evidence of risk factors for this injury. The development of avascular necrosis and osteoarthritis was determined from the follow-up radiographs and MR scans. The impact of new military instructions on the management of hip-related pain was assessed following their introduction in 1986. The preventive regimen (1986) improved awareness and increased the detected incidence from 13.2 per 100,000 service-years (1970 to 1986) to 53.2 per 100,000 (1987 to 1990). No patient developed displacement of the fracture or avascular necrosis of the femoral head, or suffered from adverse complications. No differences were found in MRI-measured hip joint spaces at final follow-up. The mean Harris Hip Score was 97 (70 to 100) and the Visual Analogue Scale 5.85 mm (0 to 44). Non-operative treatment, including avoidance of or reduced weight-bearing, gave favourable short- and long-term outcomes. Undisplaced fatigue fractures of the femoral neck neither predispose to avascular necrosis nor the subsequent development of osteoarthritis of the hip.

Vitamin D fortification as public health policy: significant improvement in vitamin D status in young Finnish men.

BACKGROUND: Vitamin D insufficiency is common in northern countries during wintertime. In Finland, after the recommendation by the Ministry of Social Affairs and Health, vitamin D has been added to liquid milk products and margarines from February 2003. OBJECTIVE: We determined the effects of national policy on vitamin D fortification on vitamin D status among young Finnish men. DESIGN: A comparison before and after intervention with study population of 196 young Finnish men (18-28 years) was carried out. Serum 25-hydroxyvitamin D3 (25-OHD3) concentrations were determined with the OCTEIA enzymeimmunoassay by IDS (Immunodiagnostic Systems Limited, Bolden, UK) in January 2003 (n = 96) and in January 2004 (n = 100), nearly 1 year after national vitamin D fortification had started. RESULTS: The mean serum 25-OHD3 concentrations during the wintertime increased by 50% after implementation of the vitamin D fortification of dairy products. Correspondingly, the prevalence of vitamin D insufficiency (serum 25-OHD3 < 40 nmol/l) was decreased by 50% from 78% in January 2003 to 35% in January 2004. CONCLUSIONS: Our results demonstrate that national vitamin D fortification substantially improved the vitamin D status of young Finnish men. Still, a third remained vitamin D insufficient.

Tissue restoration after resorption of polyglycolide and poly-laevo-lactic acid screws.

Despite worldwide clinical use of bio-absorbable devices for internal fixation in orthopaedic surgery, the degradation behaviour and tissue replacement of these implants are not fully understood. In a long-term experimental study, we have determined the patterns of tissue restoration 36 and 54 months after implantation of polyglycolic acid and poly-laevo-lactic acid screws in the distal femur of the rabbit. After 36 months in the polyglycolic acid group the specimens showed no remaining polymer and loose connective tissue occupied 80% of the screw track. Tissue restoration remained poor at 54 months, the amounts of trabecular bone and haematopoietic elements being significantly lower than those in the intact control group. The amount of trabecular bone within the screw track at 54 months in the polyglycolic acid group was less than in the empty drill holes (p = 0.04). In the poly-laevo-lactic acid group, polymeric material was present in abundance after 54 months, occupying 60% of the cross-section of the core area of the screw track. When using absorbable internal fixation implants we should recognise that the degradation of the devices will probably not be accompanied by the restoration of normal trabecular bone.

Fatigue injuries of the femur.

The purpose of this study was to describe the anatomical distribution and incidence of fatigue injuries of the femur in physically-active young adults, based upon MRI studies. During a period of 70 months, 1857 patients with exercise-induced pain in the femur underwent MRI of the pelvis, hips, femora, and/or knees. Of these, 170 patients had a total of 185 fatigue injuries, giving an incidence of 199 per 100 000 person-years. Bilateral injuries occurred in 9% of patients. The three most common sites affected were the femoral neck (50%), the condylar area (24%) and the proximal shaft (18%). A fatigue reaction was seen in 57%, and a fracture line in 22%. There was a statistical correlation between the severity of the fatigue injury and the duration of pain (p = 0.001). The location of the pain was normally at the site of the fatigue injury. Fatigue injuries of the femur appear to be relatively common in physically-active patients.

Bone stress injuries.

Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but also among otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient's history of increased physical activity and on imaging findings. The general symptom of a bone stress injury is stress-related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis, because if the diagnosis is not delayed most bone stress injuries heal well without complications.

MR imaging, bone scintigraphy, and radiography in bone stress injuries of the pelvis and the lower extremity.

PURPOSE: To compare MR imaging, radiography and bone scintigraphy in the diagnosis of stress injuries to bones of the pelvis and lower extremity. MATERIAL AND METHODS: Fifty consecutive conscripts with clinical signs of a stress injury to bone underwent MR imaging and bone scintigraphy. Forty-three patients also had radiographs available. Bone scintigraphy served as a gold standard. RESULTS: Compared to the bone scintigraphy, the sensitivity of radiography was 56%, specificity 94%, accuracy 67%, positive predictive value (PPV) 95%, and negative predictive value (NPV) 48%. The kappa value for radiography and bone scintigraphy was fair (0.39). Correspondingly, the sensitivity of MR imaging was 100%, specificity 86%, accuracy 95%, PPV 93% and NPV 100%. The kappa value for MR imaging and bone scintigraphy was very good (0.89). MR imaging depicted 3 bone stress injuries that were not visible on bone scintigraphy. Positive findings obtained from radiography correlated with MR signs of fracture line or callus (p<0.001). CONCLUSION: MR imaging is more sensitive than two-phase bone scintigraphy, and MR imaging should be used as the gold standard in the assessment of stress injuries of bone. Radiography reveals mainly the late phases of bone stress injuries, such as stress fracture and callus.

Dynamic contrast-enhanced MR imaging in symptomatic bone stress of the pelvis and the lower extremity.

PURPOSE: To assess the value of dynamic contrast-enhanced MR imaging in bone stress of the pelvis and the lower extremity. MATERIAL AND METHODS: Thirty patients (37 reactions; aged 17-25 years, mean 20.5 years) with MR findings of 37 bone stress reactions were examined using dynamic gadolinium contrast enhancement. The enhancement was evaluated with time-intensity curves. The highest slope and maximum enhancement values were calculated and compared with the different precontrast MR imaging signs of bone stress reactions. RESULTS: There was a significant difference in the highest slope values between the site of the bone stress reaction and the reference points. In 24 of the 37 reactions the dynamic contrast enhancement was regarded as positive. A fracture line, callus, and muscle edema were the MR imaging signs which had a significant correlation to the dynamic contrast enhancement. Neither periosteal nor marrow changes showed any significant correlation. A new MR grading system for bone stress reactions could be assessed. CONCLUSION: Increased tissue perfusion could be seen if precontrast MR imaging revealed callus, fracture line or muscle edema surrounding the bone stress reaction.

MR imaging of overuse injuries of the Achilles tendon.

OBJECTIVE: This study was conducted to illustrate and classify the abnormalities found on high-resolution MR imaging of symptomatic Achilles tendons in athletic adult patients. SUBJECTS AND METHODS: One hundred patients with 118 painful Achilles tendons were imaged with a 1.5-T magnet. The tendon, peritendinous tissues, tendon insertion, and musculotendinous junction were examined on MR imaging. Twenty-eight patients underwent surgery, and histopathologic samples were taken in 13. Long-term follow-up was performed, on average, 3.4 years after MR imaging. RESULTS: Of 118 painful Achilles tendons, abnormalities were detected in 111. These were in the tendon (n = 90), surrounding structures, or both. Fifty-four tendons had a focal area of increased intratendinous signal, best detected on axial high-resolution T1-weighted gradient-echo MR imaging. Histopathology confirmed abnormal tendon structure. Of the 21 surgically proven foci of tendinosis, 20 were revealed on MR imaging. At the level of the insertion, changes were found in the tendon in 15%, in the retrocalcaneal bursa in 19%, and in the calcaneal bone marrow in 8% of the studies. Abnormalities in peritendinous soft tissues were detected in 67%. More than one type of abnormality was found in 64% of the studies. CONCLUSION: Lesions in the Achilles tendon and in the peritendinous structures can have similar clinical presentation. MR imaging detects and characterizes these changes. A more specific diagnosis and prognosis can be made with the use of MR imaging than with clinical examination alone.

Population based epidemiologic and morphologic study of femoral shaft fractures.

The epidemiologic and morphologic features of all femoral shaft fractures in skeletally mature patients treated during a 10-year period in a semi-urban county were analyzed. Among an average adult population of 202,592 residents, 192 people sustained 201 traumatic femoral shaft fractures during the study period. The incidence was 9.9 fractures per 100,000 person-years. The highest age and gender specific incidences were seen in males from 15 to 24 years of age and in females 75 years of age or older. Seventy-five percent (151) of the fractures were the result of a high-energy trauma, 131 of which occurred in road traffic accidents. Unexpectedly, there were 50 low-energy fractures. Fractures of the middle 1/3 of the diaphysis were 79%. The majority, 155 (77%), of all fractures were transverse, oblique, or oblique transverse. Regarding the degree of comminution, the Winquist and Hansen Grade 0 (noncomminuted) fracture was the most common. Forty-eight percent of fractures were AO Type A, 39% were Type B, and 13% were Type C fractures. Of the 25 open fractures, 14 were Gustilo Type II. All six Type III open injuries were Type IIIA. Based on the data from the current study, most of the femoral fractures in this community might be treated adequately with conventional intramedullary nails, rather than using interlocking nails, provided the stability of fixation and fracture alignment can be maintained. Preventive measures against femoral shaft fractures should focus on protection of automobile drivers, especially young men, and on effective treatment of osteoporosis in elderly women.

Adverse tissue reactions to bioabsorbable fixation devices.

Among 2528 patients operated on using pins, rods, bolts, and screws made of polyglycolic acid or polylactic acid, 108 (4.3%) were affected by a clinically significant local inflammatory, sterile tissue reaction. The three most common indications for the use of these fixation devices were a displaced malleolar fracture, a chevron osteotomy for hallux valgus, and a displaced fracture of the radial head. In 107 patients, the reaction was elicited by a polyglycolic acid implant, and in one patient by a polylactic acid implant. The incidences were 5.3% (107 of 2037) and 0.2% (one of 491), respectively. The adverse tissue responses to polyglycolic acid were seen 11 weeks after the operation, on average, whereas the reaction to polylactic acid occurred 4.3 years after fixation of an ankle fracture. The mild reactions consisted of a painful erythematous papule of a few weeks' duration. Those of medium severity had a sinus that discharged remnants of the implant for up to 6 months. In the patients affected by severe reactions, extensive osteolytic lesions developed at the implant tracks. The histopathologic picture was that of a nonspecific foreign body reaction. In four patients with vigorous reactions, an arthrodesis of the wrist or ankle later was necessary because of severe osteoarthritis. Several markers of increased risk of the occurrence of a foreign body reaction were found. These included a poorly vascularized bone section such as scaphoid, use of a quinone dye as an additive in the polymer, and an implant geometry with large surface area (screw versus pin or rod). For polyglycolic acid implants, the risk of an adverse tissue response in a given clinical situation can be estimated from the findings of this study. For slow degrading polymers like polylactic acid, however, the ultimate biocompatibility still is unsettled, and additional clinical research with long followup is required.

High-resolution MR imaging of the asymptomatic Achilles tendon: new observations.

OBJECTIVE: Our aim was to describe the normal appearance of the Achilles tendon and peritendinous tissues in asymptomatic active volunteers using high-resolution MR imaging. MATERIALS AND METHODS: One hundred clinically asymptomatic Achilles tendons were imaged at 1.5 T with axial high-resolution T1-weighted gradient-echo (fast low-angle shot [FLASH]) and short inversion time inversion recovery (STIR) sequences. The tendons, peritendinous tissues, tendon insertions, and musculotendinous junctions were separately evaluated by two observers. RESULTS: The average anteroposterior diameter (+/-SD) of the asymptomatic Achilles tendons was 5.2+/-0.73 mm. The anterior margin was flat or concave in all, except for 10 tendons that showed mild convexity. A wave-like bulge, which shifted from lateral to medial in the craniocaudal direction, was detected in the anterior margin of 56 tendons. The signal intensity was heterogeneous in 45 tendons. In these tendons, distal stripes or punctate foci were seen. A small (3 mm) intermediate intensity intratendinous region thought to represent tendon degeneration was detected in four cases on FLASH images. The retrocalcaneal bursae contained a prominent fluid collection in 15 cases. The paratenon was visualized in all cases on both FLASH and STIR images. CONCLUSION: High-resolution MR imaging depicts the Achilles tendon and peritendinous soft tissues in great detail. The normal anatomy of the asymptomatic Achilles tendon is variable. We postulate that the variability may be a potential source of diagnostic misinterpretation.

Intraosseous plating: a new method for biodegradable osteofixation in craniofacial surgery.

Biodegradable miniplates and screws offer special possibilities for surgical techniques because the removal operation is avoided. In areas beneath thin skin, intraosseous plating could be preferable to avoid palpability and transient swelling during resorption. The tissue reaction to a 0.5-mm-thick self-reinforced poly-L-lactide (SR-PLLA) plate fixed with an SR-PLLA miniscrew was studied histologically and histomorphometrically after implantation into the calvarium of six young sheep. After follow-up periods of 6, 20, and 52 weeks, no signs of adverse tissue reaction such as clinically manifest foreign body reaction or histologically manifest osteolysis were noted. By 52 weeks the implants were largely in direct contact with remodeled, dense bone tissue. No signs of fragmentation or resorption were noted in the intraosseous parts of the implants, whereas the screw head had been fragmented and was undergoing resorption at 52 weeks. The screw head is unnecessary in this plating method and could have been removed with a hot wire loop. The excellent biocompatibility of the mechanically strong, resorbable SR-PLLA plate with miniscrew fixation provides a possibility for intraosseous plating in less loaded craniofacial areas, especially in areas with very thin soft-tissue coverage.

Consolidation of craniotomy lines after resorbable polylactide and titanium plating: a comparative experimental study in sheep.

The consolidation process of craniotomy lines in a skeletally immature large mammal was studied. A traditional narrow titanium miniplate was compared with a 0.5-mm-thick, 12-mm-wide absorbable punched self-reinforced poly-L-lactide (SR-PLLA) plate, both fixed with titanium miniscrews over bilateral parietal 2.5-mm-wide stable transosseous craniotomies on nine female sheep (16 to 20 months old). After 6, 12, 20, 52, and 104 weeks, cross-sectional histology, histomorphometry, and oxytetracycline chloride fluorescence studies were done to compare the healing process of the craniotomy lines and to study the biocompatibility and the degradation process of the SR-PLLA plate. The consolidation pattern supported the principle of guided tissue regeneration: under the wide, resorbable plate osseous bridging proceeded evenly throughout the line, whereas titanium plating led to bulky, uneven growth in the bone margins. All SR-PLLA-plated osteotomy lines had healed completely by 20 weeks, whereas none of the titanium-plated lines had consolidated during a follow-up of 1 year. The nonossified gaps were filled with dense connective tissue. Histomorphometric analysis showed that osseous bridging proceeded significantly faster on the resorbable plate side compared with the titanium side (p < 0.001). The osteoid surface fraction over the total trabecular surface was highest at 6 weeks, being 63 percent on the SR-PLLA side and only 36 percent on the titanium side. The oxytetracycline chloride fluorescence studies confirmed these findings. After 52 weeks, there was no osteoid or oxytetracycline chloride fluorescence left as a sign of terminated ossification, even in the nonconsolidated titanium sides. Microscopic cracking of the plate was evident at 12 to 20 weeks, and the first signs of active resorption were present at 52 weeks. After 2 years, the plate had disappeared and tiny polylactide particles were being actively reabsorbed. The biocompatibility of SR-PLLA and titanium was good, and no adverse cellular reactions to these materials were noted, except a clinical foreign body reaction caused by loosened titanium miniscrews. A densely punched, 0.5-mm-thick self-reinforced PLLA plate seems to retain its integrity for a sufficiently long time to complete osseous healing of a 2.5-mm-wide craniotomy line in the sheep calvarial area. A thin, wide fixation plate enables superior healing, especially in osseous defects. The degradation process of the SR-PLLA plate begins within 1 year and is far advanced after 2 years. By using absorbable SR-PLLA fixation plates instead of metallic plates, a subsequent operation for the removal of the implants can be avoided. SR-PLLA devices could thus be a potential additive or even alternative to metallic implants in craniofacial surgery.

Comparison of the tissue response to absorbable self-reinforced polylactide screws and metallic screws in the fixation of cancellous bone osteotomies: an experimental study on the rabbit distal femur.

The availability of absorbable fracture-fixation devices for clinical use calls for better knowledge of the reaction of bone tissue to absorbable polyester implants as compared with similar metallic devices. To examine and compare the tissue response to biodegradable and metallic screws within cancellous bone, a transverse transcondylar osteotomy of the distal femur was fixed with absorbable self-reinforced polylevolactide screws in 35 rabbits and with stainless-steel screws in 35 rabbits. New bone formation and consolidation of the osteotomy were examined histologically, histomorphometrically, and microradiographically within standardized sample fields 1, 3, 6, 12, 24, 36, and 48 weeks postoperatively. The intact contralateral femur served as the control. A vigorous osteoconductive response to the polylevolactide screws was observed at 3 weeks postoperatively, and the osteoid surface fraction was significantly higher in all follow-ups than in the contralateral femora. In the femora with metallic screws, new bone formation was seen 3, 6, and 12 weeks postoperatively, but at 24, 36, and 48 weeks the osteoid surface fraction did not differ significantly from that of the intact control femora. The total bone area was significantly larger in the femora with self-reinforced polylevolactide screws than in the control bone 6-48 weeks postoperatively; in the femora with metallic screws, this was found only at 6 and 12 weeks. After 48 weeks, the femora fixed with metallic screws had statistically smaller total bone area than the intact control femora. Solid bone union was seen in 84% of the osteotomies in the self-reinforced polylevolactide group and in 76% of those in the metallic group after 3 weeks or more. No signs of degradation of the self-reinforced polyleuolactide implant and only a mild foreign-body reaction with no accumulations of inflammatory cells to either self-reinforced polylevolactide or metallic screws were observed during the follow-up period. Both types of screws seemed to induce an osteostimulatory response around their threads. This phenomenon was transient for metallic screws but lasted for at least 48 weeks for self-reinforced polylevolactide screws. The polylevolactide screw does not seem to cause osteopenia at the implantation site. The fixation properties of both self-reinforced polylevolactide screws and metallic screws appear to be sufficient for the fixation of small fragments of cancellous bone.