Partial Union Research Articles

Revision of failed total ankle arthroplasty to a hindfoot fusion: 23 consecutive cases using the Phoenix nail.

The aim of this study was to present a series of patients with aseptic failure of a total ankle arthroplasty (TAA) who were treated with fusion of the hindfoot using a nail. A total of 23 TAAs, in 22 patients, were revised for aseptic loosening and balloon osteolysis to a hindfoot fusion by a single surgeon (NH) between January 2012 and August 2014. The procedure was carried out without bone graft using the Phoenix, Biomet Hindfoot Arthrodesis Nail. Preoperative investigations included full blood count, CRP and ESR, and radiological investigations including plain radiographs and CT scans. Postoperative plain radiographs were assessed for fusion. When there was any doubt, CT scans were performed. The mean follow-up was 13.9 months (4.3 to 37.2). Union occurred at the tibiotalar joint in 22 ankles (95.6%) with one partial union. Union occurred at the subtalar joint in 20 ankles (87%) of cases with two nonunions. The nail broke in one patient with a subtalar nonunion and revision was undertaken. The only other noted complication was one patient who suffered a stress fracture at the proximal aspect of the nail, which was satisfactorily treated conservatively. This study represents the largest group of patients reported to have undergone revision TAA to fusion of the hindfoot with good results Cite this article: Bone Joint J 2018;100-B:475-9.

Reliability of Diagnosis of Partial Union of Scaphoid Waist Fractures on Computed Tomography

Computed tomography (CT) is increasingly used not just to diagnose union but also to estimate the percentage of the fracture gap that is bridged by healing bone. This study tested the primary null hypothesis that there is no agreement between observers on the extent of union of a scaphoid waist fracture on CT. CT scans of 13 nondisplaced scaphoid waist fractures treated nonoperatively were rated by 145 observers. CT scans were done 10 to 12 weeks after injury. Observers were asked to "eyeball" measure percentage of union. We found that there was a moderate agreement on the categorical degree of partial union of a scaphoid waist fracture on CT (k = 0.34). Agreement on the location of bony bridging was slight (k = 0.31). We concluded that there is limited reliability of diagnosis of partial union of a scaphoid waist fracture on CT and that this should be taken into account in both patient care and research. This is a Level III, diagnostic study.

Successful joint preservation of distal radius osteosarcoma by en bloc tumor excision and reconstruction using a tumor bearing frozen autograft: a case report

BackgroundThe wrist joint is an extremely rare site for osteosarcoma. Joint structure preservation to maintain good limb function is well described in case of knee osteosarcoma, whereas it is not described in case of wrist joint osteosarcoma. In this report, we present the first case of joint preservation surgery to treat distal radius osteosarcoma using a tumor bearing autograft treated with liquid nitrogen.Case presentationA 46-year-old male presented with swelling and pain in the right wrist and was diagnosed with conventional osteosarcoma of the distal radius. The patient responded well to neoadjuvant chemotherapy and the tumor shrank remarkably. Wide tumor excision to preserve the radiocarpal joint and reconstruction with a tumor bearing frozen autograft were performed. Partial bone union was detected 3 months postoperatively and complete bone union was detected 9 months postoperatively. Following the surgery, there was immediate commencement of the range of motion (ROM) training in both the wrist and fingers. At the final postoperative follow-up of 41 months, the patient had normal ROM in the wrist, fingers, and forearms, with a score of 100% in the Musculoskeletal Tumor Society (MSTS) score and was disease free.ConclusionWe present the first case in which en bloc tumor excision with joint preservation of the wrist and reconstruction using a tumor bearing frozen autograft were performed. The surgery yielded excellent hand, wrist, and forearm function at the final follow-up.

Subtypes of endothelial progenitor cells affect healing of segmental bone defects differently.

Treating fracture nonunion with endothelial progenitor cells (EPCs) is a promising approach. Nevertheless, the effect of different EPC-related cell populations remains unclear. In this study, we compared the therapeutic potential of early (E-EPCs) and late EPCs (L-EPCs). Male Fischer 344 rats were used for cell isolation and in vivo experiments. Bone marrow-derived E-EPCs and L-EPCs were kept in culture for seven to tendays and four weeks, respectively. For each treatment group, we seeded one million cells on a gelatin scaffold before implantation in a segmental defect created in a rat femur; control animals received a cell-free scaffold. Bone healing was monitored via radiographs for up to tenweeks after surgery. In vitro, secretion of vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP)-2 was quantified by ELISA for both cell populations. Tube formation assays were also performed. Final radiographs showed complete (four out of five rats) or partial (one out of five rats) union with E-EPC treatment. In contrast, complete healing was achieved in only one of five animals after L-EPC implantation, while control treatment resulted in nonunion in all animals. In vitro, E-EPCs released more VEGF, but less BMP-2 than L-EPCs. In addition, L-EPCs formed longer and more mature tubules on basement membrane matrix than E-EPCs. However, co-culture with primary osteoblasts stimulated tubulogenesis of E-EPCs while inhibiting that of L-EPCs. We demonstrated that bone marrow-derived E-EPCs are a better alternative than L-EPCs for treatment of nonunion. We hypothesize that the expression profile of E-EPCs and their adaptation to the local environment contribute to superior bone healing.

Four-corner fusion of the wrist: clinical and radiographic outcome of 31 patients

Four-corner fusion is a rational surgical option for the management of degenerative conditions of the wrist. Most related studies have compared four-corner fusion with scaphoid excision or proximal row carpectomy, with a variety of reported results. To enhance the literature, we performed this study to evaluate a series of patients with degenerative conditions of the wrist treated with four-corner fusion using 3 surgical techniques and to discuss the clinical and radiographic outcome of the patients. We retrospectively studied 31 patients (24 men, 7 women; mean age, 43years; 9 heavy manual laborers) who underwent four-corner fusion of their wrists for degenerative conditions from 2005 to 2015. Internal fixation was done using multiple Kirschner wires (14 patients), headless compressive screws (8 patients), or a circular plate (9 patients). Mean follow-up was 4years (1-11years). We evaluated the clinical outcome with the Patient-Rated Wrist Evaluation (PRWE) score and fusion with radiographs. All patients experienced improvement of their pain, function, range of motion and grip strength (p<0.05). Twenty-three patients (74%) reported no pain, and eight patients reported mild, occasional pain. Twenty-one patients (68%) were able to do usual and specific activities. Mean wrist motion improved to 70% and mean grip strength improved to 85% of opposite wrist. Two heavy manual labor patients requested a job modification because of wrist impairment. Radiographs of the wrist showed fusion of all fused joints in 28 (90.3%) patients and partial fusion in three patients (9.7%). No patient with partial fusion required a reoperation for symptomatic nonunion until the period of this study. Three patients experienced complications (10%). Two patients treated with a circular plate experienced complex regional pain syndrome and painful implant impingement; another patient treated with Kirschner wires and headless compression screws experienced radiolunate arthritis from impingement of the lunate screw to the radius. Four-corner fusion is a reliable limited wrist fusion technique that provides pain relief, grip strength and satisfactory range of motion in patients with degenerative conditions of the wrist. Partial union is more common with Kirschner wire fixation and complications are more common with circular plate fixation.

Wrist Pain in a Collegiate Golfer

HISTORY: year-old right-handed senior male golfer presented with right wrist pain. History was significant for 4 months of pain that worsened after striking a tree root while playing golf in the spring. He was evaluated and radiographs were negative at that time. His pain subsided with 3 weeks of rest. He returned to his home in Europe for summer vacation, and had increasing pain with golfing activity over 6-8 weeks. An MRI in Europe was reported to show edema in scaphoid, and a CT scan reportedly showed a non-displaced healing scaphoid fracture. He was treated with relative rest and physiotherapy for 6 weeks. At his follow-up visit upon returning to school for the fall, he reported improvement in symptoms. He was able to do normal daily activities without pain, but still had some pain with weight-bearing activities. PHYSICAL EXAMINATION: Examination of his right wrist revealed normal alignment without deformity, ecchymosis, erythema or swelling. He had no pain to palpation over the anatomic snuffbox. He had full range of motion and normal strength of his right wrist to flexion, extension, ulnar deviation, radial deviation, pronation, and supination without pain. He had normal grip strength. He had mild discomfort on the radial side of his right wrist with weight-bearing on his right hand. Neurovascularly intact in his right upper extremity. DIFFERENTIAL DIAGNOSES: Scapholunate ligament injury Kienbock’s disease Scaphoid impaction syndrome Scaphoid fracture De Quervain’s tenosynovitis TESTS AND RESULTS: X-ray of right wrist: --Scaphoid waist fracture with evidence of healing CT of right wrist: --Scaphoid waist fracture with evidence of partial non-union along the volar margin FINAL WORKING DIAGNOSIS: Partial union of mid waist scaphoid fracture TREATMENT AND OUTCOME: Initially, immobilization in an Exos thumb spica splint. Bone stimulator twice daily for 20 minutes. Gradually progressed him back to golfing activity starting with chipping and putting. He was still healing as of last set of X-rays at 8 week follow-up. He progressed through putting and chipping without pain. We cleared him to start full golf activity.

Unions in a frictional labor market

A labor market with search and matching frictions, where wage setting is controlled by a monopoly union that follows a norm of wage solidarity, is found vulnerable to substantial distortions associated with holdup. With full commitment to future wages, the union achieves efficient hiring in the long run, but hikes up wages in the short run to appropriate rents from firms. Without commitment, in a Markov-perfect equilibrium, hiring is too low both in the short and the long run. The quantitative impact is demonstrated in an extended model with partial union coverage and multiperiod union contracting.

A Short-Term Retrospective of First Metatarsophalangeal Joint Arthrodesis Using a Plate With PocketLock Fixation.

Various techniques have been described for arthrodesis of the first metatarsophalangeal (MTP) joint. The purpose of this study was to retrospectively review the results of fixation for the first MTP arthrodesis of patients treated using dome-shaped reamers to prepare the joint surfaces and a novel MTP Plate with PocketLock fixation. Between July 2012 and November 2013, 16 feet in 16 patients were treated with a first MTP arthrodesis with a MTP Plate with PocketLock fixation. The mean patient age was 58.8 years (range, 46-82 years). Physical and radiographic examinations were performed at follow-up visits. The average follow-up period was 17.3 months. The radiographs were examined for union (3 bridging cortices), time to union, hardware failure, or other radiographic complications. The charts were reviewed to assess AOFAS-MTP-IP (American Orthopaedic Foot & Ankle Society metatarsophalangeal-interphalangeal) scores and postoperative complications. Fusion was seen in 11 of 16 feet (68.8%) and partial union in 1 patient (6.3%). Five nonunions (31.2%) were noted in the sample group: All were symptomatic and required revision surgery. No malunions were identified in our sample. One hardware failure was documented in a nonunion patient. The mean time to osseous union was 81.7 ± 15.9 days. The preoperative AOFAS MTP-IP score was 55.6 and the postoperative score was 64.7. The high nonunion and revision surgery rates demonstrate that this particular plate should be used with caution for a first MTP joint arthrodesis. Therapeutic, Level IV: Case series.

Bone Fragment Union and Remodeling After Arthroscopic Bony Bankart Repair for Traumatic Anterior Shoulder Instability With a Glenoid Defect

Background: Although good clinical outcomes have been reported after arthroscopic bony Bankart repair, the extent of bone union is still unclear. Purpose: To investigate bone union after arthroscopic bony Bankart repair and its influence on postoperative recurrence of instability. Study Design: Cohort study; Level of evidence, 3. Methods: Among 113 consecutive shoulders that underwent arthroscopic bony Bankart repair, postoperative evaluation of bone union by computed tomography (CT) was performed at various times in 81 shoulders. Bone union was investigated during 3 periods: 3 to 6 months postoperatively (first period), 7 to 12 months postoperatively (second period), and 13 months or more postoperatively (third period). The influence of the size of the preoperative glenoid defect and the size of the bone fragment on bone union was investigated, as well as the influence of bone union on postoperative recurrence of instability. In shoulders with bone union, bone fragment remodeling and changes in the glenoid defect size were also investigated. Results: The bone union rate was 30.5% in the first period, 55.3% in the second period, and 84.6% in the third period. Among 53 shoulders with CT evaluation in the second period or later and follow-up for a minimum of 1 year, there was complete union in 33 shoulders (62.3%), partial union in 3 (5.7%), nonunion in 8 (15.1%), and no fragment on CT in 9 (17.0%). The complete union rate was 50% for 22 shoulders with small bone fragments (<5% of the glenoid diameter), 56.3% for 16 shoulders with medium fragments (5%-10%), and 86.7% for 15 shoulders with large fragments (>10%). The recurrence rate for postoperative instability was only 6.1% for shoulders with complete union, while it was 50% for shoulders with partial union, nonunion, no fragment, and no fragment on CT. The recurrence rate was significantly higher (36.4%) in shoulders with small fragments, but it was significantly lower in shoulders with bone union. In shoulders with bone union, the bone fragment frequently became larger over time, while the size of the glenoid defect decreased significantly from 18.6% preoperatively to 4.7% postoperatively. Conclusion: Bone union was not always achieved after arthroscopic bony Bankart repair, and union was often delayed. Recurrence of instability was significantly more frequent when bone union failed. The size of the glenoid defect decreased significantly in shoulders with bone union.

Chronology of fusion of the primary and secondary ossification centers in the human sacrum and age estimation in child and adolescent skeletons

Little is known about fusion times of the primary and secondary centers of ossification in the sacrum, particularly from dry bone observations. In this study, the timing of union of these centers was studied in a sample of modern Portuguese skeletons (90 females and 101 males) between the ages of 0 and 30 years, taken from the Lisbon documented skeletal collection. A three-stage scheme was used to assess fusion status between ossification centers as unfused, partially fused and completely fused. Posterior probability tables of age, given a certain stage of fusion, were calculated for most anatomical locations studied using both reference and uniform priors. Partial union of primary centers of ossification was observed from 1 to 8 years of age and partial union of secondary centers of ossification was observed from 15 to 21 years of age. The first primary centers of ossification to complete fusion are the neural arch with the centrum of the fifth sacral vertebrae and the last are the costal element with the centrum of the first sacral vertebra. The annular and sacroiliac epiphyses are the first, among the secondary centers of ossification observed, to complete fusion, after which the lateral margin fuses. This study offers information on timing of fusion of diverse locations in the developing sacrum useful for age estimation of complete or fragmented immature human skeletal remains and fills an important gap in the literature, by adding to previously published times of fusion of primary and secondary ossification centers in this sample.

Timing of fusion of the ischiopubic ramus from dry bone observations

There is little information about the age at which the ischiopubic ramus fuses derived from dry bone observations. This study documents the age ranges for union of the ischiopubic ramus in a sample of 148 known sex and age skeletons from Portugal, with ages ranging from birth to 20 years, using a three-stage scheme. The oldest female with an unfused ramus is 11 years old and the oldest male is 8 years old. The youngest male with a completely fused ramus is 7 years old, and the youngest female is 5 years old. Despite the relatively large sample size, partial fusion was a rare event to record as only two individuals were at this stage and these seemed relatively older than expected (12 and 14 years of age). The likely age interval for partial union of the ramus was subsequently estimated from logistic regression, for both sexes separated and combined. In the sex-pooled sample, the inter-quartile range (25th–75th percentile) for the median age of fusion is 7–11 years and the 10th–90th percentile range is 4–15 years. The scarcity of data on the age of ischiopubic fusion may be related to biases in the sample or to fusion occurring rapidly in this anatomical location. Additional studies may be required to assess the accuracy of the ages reported here, but at present this study provides the most comprehensive assessment of timing of fusion at the ischiopubic ramus from observations of dry bone specimens.

Multiplanar reconstruction computed tomography for diagnosis of scaphoid waist fracture union: a prospective cohort analysis of accuracy and precision

To examine reliability and validity concerning union of scaphoid fractures determined by multiplanar reconstruction computed tomography randomized at 6, 12, and 24weeks after injury. We used Fleiss' kappa to measure the opinions of three observers reviewing 44 sets of computed tomographic scans of 44 conservatively treated scaphoid waist fractures. We calculated kappa for the extent of consolidation (0-24%, 25-49%, 50-74%, or 75-100%) on the transverse, sagittal and coronal views. We also calculated kappa for no union, partial union, and union, and grouped the results for 6, 12, and 24weeks after injury. As the reference standard for union, CT scans were performed at a minimum of 6months after injury to determine validity. Overall inter-observer agreement was found to be moderate (κ = 0.576). No union (κ = 0.791), partial union (κ = 0.502), and union (κ = 0.683) showed substantial, moderate, and substantial agreement, respectively. The average sensitivity of multiplanar reconstruction CT for diagnosing union of scaphoid waist fractures was 73%. The average specificity was 80%. Our results suggest that multiplanar reconstruction computed tomography is a reliable and accurate method for diagnosing union or nonunion of scaphoid fractures. However, inter-observer agreement was lower with respect to partial union.

The rate of successful four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate

The purpose of this study is to evaluate the rate of union after four-corner arthrodesis with a locking, dorsal circular plate comprised of polyether-ether-ketone. A retrospective review was conducted of all patients who underwent four-corner arthrodesis with a locking, dorsal circular plate at our institution from January 2005 to May 2009. The primary outcome measure was radiographic and clinical union. During the study period, 26 consecutive wrists underwent four-corner arthrodesis with a locking, dorsal circular plate. Twenty-three wrists were included. The mean clinical follow-up was 16 months (range 3-37). Union was achieved in 22 of 23 wrists at a mean time of 3 months (range 1-12). There was one partial union that underwent successful revision arthrodesis. In summary, four-corner fusion with a polyether-ether-ketone locking, dorsal circular plate results in high union rates. The use of a radiolucent plate allows for more accurate assessment of union with the biomechanical advantages of a fixed angle construct.

Circumferential Proximal Femoral Allografts in Revision Hip Arthroplasty: Four to 20 Years Follow-Up

The purpose of this study was to analyze the clinical and radiographic results of revision of loose total hip replacements, using proximal femoral allografts and a cemented implant. We retrospectively reviewed of 28 consecutive patients. Twenty patients were available for study. Each patient was scored using a modified Harris Hip Score. Radiographs were examined for endosteal and periosteal reabsorption, allograft-host union, trochanteric migration, component loosening and heterotrophic calcification. The mean pre-operative Harris hip Score was 34 points. At the latest follow-up, the meanscore was 80 points. Nineteen cases (95%) had combined femoral defects and one patient (5%) had a segmental defect, according to the AAOS classification. Allograft resorption was seen in eight (40%) hips. There were 18 cases (90%) of allograft union, one (5%) of partial union and one (5%) of nonunion. There was one case of trochanteric migration (more than 1 cm). All femoral components were radiographically stable. The reconstruction was considered successful in 18 patients (90%). The use of proximal femoral allografts in femoral revision of loose total hip replacements has high survival and satisfactory clinical results at an average period of eight years postoperatively.

The surgical treatment of pyogenic spondylitis using posterior instrumentation without anterior debridement

There have been few reports regarding the efficacy of posterior instrumentation alone as surgical treatment for patients with pyogenic spondylitis, thus avoiding the morbidity of anterior surgery. We report the clinical outcomes of six patients with pyogenic spondylitis treated effectively with a single-stage posterior fusion without anterior debridement at a mean follow-up of 2.8 years (2 to 5). Haematological data, including white cell count and level of C-reactive protein, returned to normal in all patients at a mean of 8.2 weeks (7 to 9) after the posterior fusion. Rigid bony fusion between the infected vertebrae was observed in five patients at a mean of 6.3 months (4.5 to 8) post-operatively, with the remaining patient having partial union. Severe back pain was immediately reduced following surgery and the activities of daily living showed a marked improvement. Methicillin-resistant Staphylococcus aureus was detected as the causative organism in four patients. Single-stage posterior fusion may be effective in patients with pyogenic spondylitis who have relatively minor bony destruction.

Arthroscopically assisted internal fixation of the symptomatic unstable os acromiale with absorbable screws

Symptomatic meso- type os acromiale is a common pathology with inconsistent outcomes of treatment with various surgical techniques. We report the outcome of a new technique for arthroscopic fusion of symptomatic os acromiale with absorbable screws. The study included 8 shoulders in 8 patients with symptomatic meso- type os acromiale who were treated with the use of a new technique for arthroscopic fusion with absorbable screws. The mean age was 54 years (range, 38-67 years), and the mean time from onset of symptoms to surgery was 18 months (range, 9-25 months). No patients reported a specific traumatic event before the onset of symptoms, and all noted the insidious onset of pain with no precipitating event. The average length of follow-up was 22 months (range, 12-36 month). The average Constant score improved from 49 points (range, 35-57 points) to 81 points (range, 75-86 points). The average satisfaction score improved from 4.5 of 10 (range, 2-6) to 8.5 of 10 (range 7-9). All patients made a good clinical recovery at 3 to 6 months after surgery. At the last follow-up, full radiographic union was observed in 6 patients, partial union in 1 patient, and persistent radiologic nonunion in 1 patient. Anterior bulging of the absorbable screws was noted in 2 patients, and the screws were trimmed 6 months after the first procedure. We have found that this new arthroscopic technique of fixation of os acromiale with absorbable screws provides promising clinical, cosmetic, and radiologic results with high patient satisfaction.

The results of Grice Green subtalar arthrodesis of valgus foot in spina bifida

Background:Valgus foot is a common foot deformity in spina bifida. The most popular operation for the valgus deformity has been the Grice talocalcaneal blocking. It has not been studied primarily in children with spina bifida. We report a prospective series, we present the results of hind foot valgus deformity of children with spina bifida, using Grice talocalcaneal arthrodesis with a tricortical iliac bone graft.Materials and Methods:Between May 2000 and December 2003, 21 patients with bilateral (42 feet) valgus deformity of feet underwent surgery. There were 7 males and 14 females. The mean age of patients was 67.7 months (range 50–108 months).Results:The total number of feet that had nonunion was 11, in 7 of them the grafts were completely reabsorbed and the outcome of all these feet was unsatisfactory. Four feet had partial union of which three had unsatisfactory and one had satisfactory outcome. Sixteen feet had residual valgus deformity at the last followup visit, 10 patients had nonunion, and 6 had inadequate correction. Mean preoperative talocalcaneal and calcaneal pitch angles were 48.5° and 31.9°, respectively, which decreased to 38.5° and 29.1°, respectively, postoperatively. The decrease in talocalcaneal angle and calcaneal pitch was significant between preoperative and postoperative measurements (P<0.05).Conclusion:Grice subtalar arthrodesis technique is still a valuable option for valgus foot in patients with spina bifida. In this study, we found more encouraging results in older patients.

Age estimation from stages of epiphyseal union in the presacral vertebrae

The presacral vertebrae have various secondary centers of ossification, whose timing of fusion can be used for age estimation of human skeletal remains up to the middle to the latter third decade. However, detailed information about the age at which these secondary centers of ossification fuse has been lacking. In this study, the timing of epiphyseal union in presacral vertebrae was studied in a sample of modern Portuguese skeletons (57 females and 47 males) between the ages of 9 and 30, taken from the Lisbon documented skeletal collection. A detailed photographic record of these epiphyses and the age ranges for the different stages of epiphyseal union are provided. Partial union of epiphyses was observed from 11 to 27 years of age. In general, centers of ossification begin to fuse first in the cervical and lumbar vertebrae, followed by centers of ossification in the thoracic region. The first center of ossification to complete fusion is usually that of the mammillary process in lumbar vertebrae. This is usually followed by that of the transverse process, spinous transverse process, and annular ring, regardless of vertebra type. There were no statistically significant sex differences in timing of fusion, but there was a trend toward early maturation in females for some vertebra or epiphyses. Bilateral epiphyses did not show statistically significant differences in timing of fusion. This study offers information on timing of fusion of diverse epiphyseal locations useful for age estimation of complete or fragmented human skeletal remains.

Nonunion and malunion due to insidious infection after internal fixation of bone fractures

Objective To explore an effective prevention and management of nonunion and malunion due to insidious infection after fracture internal fixation. Methods From January 2001 to January 2006,we treated 26 patients with nonunion and malunion due to insidious infection after fracture internal fixation.They were 15 cases of femoral fractures, 2 cases of ulna fractures, 3 cases of radial fracturos, 3 cases of humerus fractures, and 3 cases of tibial fractures. The patients were treated with irrigation after debridement.In 23 fractures, the internal fixation was dislodged and changed into external fixation. In the 3 cases whose internal fixation remained, instillation and drainage were conducted after debridement. Bone grafting was performed for 20 cases after replacement of internal fixation, and for 3 cases after removal of external fixation.Three patients received no bone graft. Results The preoperative X-ray findings confirmed the diagnosis of insidious infection in 21 cases, while the other 5 cases were diagnosed by bacterial culture or pathological examination of the pus and inflammatory granulation tissue found during surgery. The bacterial culture was positive in 17 cases, including 6 cases of Staphylococcus epidermidis, 8 cases of Staphylococcus aureus, and 3 cases of Escherichia coli. All the patients were followed up for 8 to 48 months, with an average of 23.5 months. Of the 26 cases, 22 obtained bony union, 2 partial union and 2 nonunion. Complications included fistula in 2 patients and infection relapse in 3 patients. Conclusions Insidious infection may be related to the bacterial toxicity, anatomical sites and surgical methods. X-ray changes may help the diagnosis of insidious infection. Surgery is necessary for management of nonunion and malunion due to insidious infection after fracture internal fixation. Key words: Fraction fixation, internal; Infection; Fractures, ununited; X-rays

The use of silk fibroin/hydroxyapatite composite co-cultured with rabbit bone-marrow stromal cells in the healing of a segmental bone defect

In a rabbit model we investigated the efficacy of a silk fibroin/hydroxyapatite (SF/HA) composite on the repair of a segmental bone defect. Four types of porous SF/HA composites (SF/HA-1, SF/HA-2, SF/HA-3, SF/HA-4) with different material ratios, pore sizes, porosity and additives were implanted subcutaneously into Sprague-Dawley rats to observe biodegradation. SF/HA-3, which had characteristics more suitable for a bone substitute based on strength and resorption was selected as a scaffold and co-cultured with rabbit bone-marrow stromal cells (BMSCs). A segmental bone defect was created in the rabbit radius. The animals were randomised into group 1 (SF/HA-3 combined with BMSCs implanted into the bone defect), group 2 (SF/HA implanted alone) and group 3 (nothing implanted). They were killed at four, eight and 12 weeks for visual, radiological and histological study. The bone defects had complete union for group 1 and partial union in group 2, 12 weeks after operation. There was no formation of new bone in group 3. We conclude that SF/HA-3 combined with BMSCs supports bone healing and offers potential as a bone-graft substitute.