Radiolucent Zone Research Articles

The monitoring of deep caries lesions after incomplete dentine caries removal: results after 14–18 months

This paper aims to assess radiographic changes after incomplete carious dentine removal and tooth sealing. Thirty-two teeth with deep caries lesions were studied. The treatment consisted of incomplete excavation, application of a Ca(OH)2 layer, sealing temporarily for a 6- to 7-month period and then restoration. Standardised bitewing radiographs were taken immediately after the temporary sealing and at 6- to 7- and 14- to 18-month intervals. The digitised images were analysed blind by image subtraction. The quantitative analyses subtractions were performed in the radiolucent zone (RZ) beneath the restoration and in two adjacent control areas (CA). Two cases were lost during the 6- to 7-month period (one pulp necrosis and one pulp exposure during removal of the provisional sealing). No difference (p > 0.05) was observed in the radiographic density of the CA and the RZ in the two experimental periods. The mean and standard deviation (grey tonalities scale) were 129.42+/-5.83 and 127.65+/-4.67 (control areas) and 132.96+/-7.41 and 132.90+/-5.99 (RZ) for the first and second experimental periods, respectively. The radiographic density of the CA differed from the RZ (Tukey test, p < 0.001). Interference in environmental conditions by partial dentine caries removal and tooth sealing arrests lesion progression, suggesting that complete dentine caries removal is not essential to control caries progression.

Primary cemented total hip arthroplasty—an Indian experience

We report outcome of 9-year follow-up of 50 Charnley cemented primary arthroplasties in 47 patients performed between 1996 and 1999. The minimum follow-up period was 5years with a mean of 7years. All hip joints were thoroughly assessed preoperatively to document patients' functional level and Harris hip score was calculated. All the patients were disabled because of pain in hip and 45 (90%) had used walking aids. At follow-up all patients were living. The radiographs of all patients were available for the entire follow-up period. Of the 50 operated hips, only 2 patients (4%) complained of pain while all the rest were free of pain. Postoperatively only 10 (20%) patients used support for walking. At follow-up none of the hips were revised. Two patients (4%) had dislocation in postoperative period in which reduction was done under anesthesia. In one patient (2%) prosthesis and cement was removed because of deep infection. In two patients (4%) radiolucent clear zone was seen at bone cement interface on acetabular side and three (6%) patients had it on femoral component. None of the patients developed deep vein thrombosis or heterotopic bone. In postoperative period the Harris hip score was calculated in each case and compared with the preoperative score to evaluate the outcome. Significant improvement was found in Harris hip score after surgery.

Ergebnisse nach Arthroplastik der Fingergrundgelenke mittels zementfreier, ungekoppelter HM-Prothese beim Rheumatiker

In 80 % of patients with rheumatoid arthritis, the metacarpophalangeal (MP) joints are involved with increasing destruction and loss of function. Silicone arthroplasty of the MP joints leads to a limited range of motion, an increase in osteolysis and fractures of the implants. The cementless, unconstrained design of the HM prosthesis is a new concept for replacing the MP joints of rheumatoid patients. Short-term and midterm results are shown. In a prospective study, 38 HM prostheses were implanted, 28 in patients with rheumatoid arthritis, four with osteoarthrosis, five with polyarthrosis and one after revision of a silicone implant. The patients were reexamined clinically and radiologically after an average follow-up of 16 months (6 - 37 months). The average active range of motion for extension, flexion increased from 0/15/65 degrees before surgery to 0/9/65 degrees after surgery. The remaining ulnar drift was 12 degrees (preoperative 18 degrees ). The average grip strength after surgery was 80 % of the opposite side. Pain in the verbal analog scale improved from 2.3 to 1.7 postoperatively. One palmar subluxation of an implant of the little finger was recognized. No infection occurred. The X-rays showed complete osteointegration in all metacarpal components. Radiolucent zones were found in progress only at the basis on the phalangeal components without radiological signs of loosening or sinking. The short- and midterm results after implantation of the cementless, unconstrained HM prosthesis show an improved hand function and pain relief. The design of the implant may solve the accepted postoperative problem of instability of the MP joints. Until now, no prosthesis had to be exchanged.

The vacuum cleft sign: an uncommon radiological sign

The intravertebral vacuum cleft sign (VCS) is an uncommon radiological sign, characterized by a radiolucent zone in the vertebral body. It is composed of 95% nitrogen and small amounts of oxygen and carbon dioxide. Post-traumatic ischemic necrosis could be its physiopathological mechanism, along with other pathologies like osteoporosis, corticosteroid therapy, diabetes, arteriosclerosis, alcoholism, multiple myeloma, bone metastasis and osteomyelitis. The broad diagnosis is made by antero-posterior X-ray, but computed tomography scan (CT scan) and magnetic resonance imaging (MRI) may help with the differential diagnosis. The aims of this paper are, on one hand, to communicate the clinical case of a 73-year-old osteoporotic woman with traumatic vertebral fractures who developed this sign in her radiological survey. On the other hand, its secondary aims are to review the medical literature about this sign and to show the clinical and radiological evolution after a percutaneous vertebroplasty.

Water uptake and release from iodine-containing bone cement.

Water uptake and release characteristics of PMMA cement containing the water-soluble contrast media iohexol or iodixanol have been investigated. The water uptake study revealed that iohexol had the highest uptake of water (3.7%) and that iodixanol had an uptake close to that of Palacos R (2.3% and 1.9%). The curves obtained showed the materials to follow classic diffusion theory, with an initial linearity with respect to t(1/2) making it possible to calculate the diffusion coefficients. This showed iohexol to have the lowest diffusion coefficient, Palacos R the highest, and iodixanol close to that of Palacos R. The release study showed that more iohexol than iodixanol was released from the bone cement; the long-term release was above 25 microg/mL for iohexol compared to slightly above 10 microg/mL for iodixanol. A microCT investigation showed that the risk of developing an observable radiolucent zone is negligible.

The significance of radiolucent zones surrounding pedicle screws. Definition of screw loosening in spinal instrumentation.

We examined the radiographs from a prospective clinical study of fixation by pedicle screws and those from an experimental study in a sheep model. In the clinical study, instruments were removed from 21 patients after implantation for 11 to 16 months and the extraction torques of the screws were recorded. A structured protocol was used for the radiological examinations. In the experimental study, loaded pedicle screw instrumentations were implanted in the sheep for six or 12 weeks. After radiological examination the pull-out resistance and the histological characteristics were studied. In the clinical study, all screws with radiolucent zones had a significantly reduced mean extraction torque compared with screws without radiolucent zones (16 +/- 10 Ncm v 403 +/- 220 Ncm; p < 0.0001). In the experimental study the mean maximum pull-out resistance for the screws with radiolucent zones was significantly lower than for those with no radiolucency (243 +/- 156 N v2214 +/- 578 N; p = 0.0006) and the mean bone-to-screw contact was reduced for screws with zones compared with those without zones (8 +/- 9% v 55 +/- 29%; p = 0.0002). Our findings showed that all screws with radiolucent zones had low extraction torques or low pull-out resistance. A radiolucent zone is a good indicator of loosening of a pedicle screw.

Indications of total ankle arthroplasty for rheumatoid arthritis: evaluation at 5 years or more after the operation

The postoperative results of total ankle arthroplasty (TAA) were surveyed, and the indications of TAA for rheumatoid arthritis (RA) were examined. We have performed TAA in properly selected patients with indication of ankle joint destruction due to RA. The subjects were 18 RA patients (20 joints) who underwent TAA between April 1988 and April 1996. Type-ND or type-TNK Bioceram was used without cement for possible revision of TAA. No destruction of large joints was found in 8 patients, and TAA was used as part of multiple arthroplasty in 10 patients. After the operation, decrease in or disappearance of joint pain was obtained, and range of motion and improved ability to walk were secured. The clinical results were superior to those obtained for 17 joints of 17 patients who underwent ankle arthrodesis during the same period. However, a radiolucent zone was observed an X-ray examination in every case, after 8 years on average (range 5–12 years) after operation. Under present conditions, ankle arthrodesis should be used for younger patients. When no destruction of the hip or knee joint is found and the patient is 65 years of age or older, we believe TAA is indicated. In cases of multiple arthroplasty or with bilateral ankle joint destruction, TAA appears to be useful if patients are young, considering their better life expectancy and quality of life.

Revision Total Hip Arthroplasty using Morselized Femoral Head Allograft and Cementless Cup in Acetabular Bone Deficiency

Purpose: This study was aimed to evaluate the clinical and radiologic results of revision total hip arthroplasty using a cementless cup and a morselized femoral head allograft in acetabular bone deficiency. Materials and Methods: From January 1992 to December 1999, the authors performed 37 revision total hip arthroplasties using morselized femoral head allografts and cementless cup. This study evaluated the clinical and radiologic results, at a mean follow-up of 50 months. We evaluated the Harris hip score clinically, and the displacement of acetabular cup by Yoder’'s criteria. Location and progression of radiolucent area within acetabular zone, which was defined by DeLee and Charnley was observed and recorded. Results: Mean Harris hip score was improved from 50.6 preoperative to 89.2 at final follow-up. A radiolucent zone between host bone and graft bone was observed in 5 cases, and between graft bone and cup in 7 cases, but all of these were less than 2 mm. The change of cup angle more than 4 degrees were observed in 3 cases in Gross type 4, 4 mm superior migration of acetabular cup was observed in 1 case in Gross type 3 and 5 mm horizontal migration was observed in 1 case in Gross type 4. Conclusion: Although the early results in revision total hip arthroplasty have been encouraging to date except for Gross type 4, a more long term follow-up study with a larger size cases are needed.

Total Knee Arthroplasty with a Low Contact Stress Total Knee System

Purpose : To analyze the clinical and radiographic results of total knee arthroplasty patients. Materials and Methods : 124 cases were analyzed clinically and radiographically, and were followed up for at least two years. Cases were divided into posterior cruciate retained group (36 cases) and sacrificed group (88 cases), and further divided into a patella resurfaced and unresurfaced group. Several factors such as pain at walking, ROM, H.S.S. score, flexion contracture for clinical evaluation were evaluated and femorotibial angle, radiologic component position, radiolucent zone according to the roentgenographic evaluation of American Knee Society were analysed. Results : Femorotibial angles changed from a varus of to a valgus of . H.S.S. scores were improved from 58.8 (38-72) to 88.8 (79-99). Flexion contracture was relieved from to and further flexion of knee joint increased from to . There was no significant difference in the H.S.S. or ROM scores of the PCL retained and sacrificed group, or between the patella resurfaced group and the unresurfaced group. There was no cases of complete radiolucency, no osteolysis and no component position change. Conclusion : According to the clinical and radiologic assessments, total knee arthroplasty using the system showed satisfactory clinical and radiographic results and no significant difference was observed between the PCL retained and sacrificed groups.

The cone hip stem: a prospective study of 13 patients followed for 5 years with RSA.

We operated on 13 patients (14 hips) with dysplastic hips, mean age 42 (28-58) years, with a cementless Cone stem and followed them for 5 years, using the Merle d'Aubigné clinical score, conventional radiography and repeated radiostereometry analyses. The clinical scores improved markedly at 4 months and still more throughout the study. None of the patients complained of thigh pain. No stem showed radiographic subsidence, but 3 stems had radiolucent zones probably indicating fibrous ingrowth. Micromigration was measured at 4 months, 1, 2 and 5 years. The mean subsidence after 5 years was 0.27 mm and the mean posterior micromigration of the head was 0.74 mm. Most of the micromigration took place within the first 4 months. We conclude that the uncemented Cone stem used in dysplastic hips has shown a good clinical outcome so far and was found to be stable on conventional radiographs and using RSA technique.

Porous Beta-Calcium Pyrophosphate as a Bone Graft Substitute in a Canine Bone Defect Model

Purpose : To evaluate the possibility of using porous -calcium pyrophosphate (-CPP) as a bone graft substitute by comparing its osteoconduction and degradation with porous hydroxyapatite (HA). Materials and Methods : Porous HA and porous -CPP were implanted in the proximal tibia of 7 dogs. Two animals were sacrificed at 8 weeks and 5 animals were sacrificed at 20 weeks after surgery. Radiographs and histologic sections were evaluated. Results : The mean period required for the radiolucent zone to disappear was 7.11.1 weeks in HA and 6.41.1 weeks in -CPP. By serial radiography, resorption was more prominent in porous -CPP than in porous HA at 8 weeks (p=0.04) and at 20 weeks. The proportion of bony tissue in the pore was 16.8% in HA and 29.7% in -CPP. The proportion of pores with bony tissue was 70.2% in HA and 62.5% in -CPP at 8 weeks. Conclusion : In -CPP, the new bone growth was as vigorous as in HA, but the degradation was more rapid than in HA. These results suggest that -CPP is a more ideal new bone graft substitute.

Bone Resorption Around Pedicle Screws After Pedicle Screw Plate Fixation

Purpose: To determine the frequency, level, distribution, onset, and pattern of progression of bone resorption that occurring around pedicle screws after pedicle screw plate fixation. Materials and Methods: Bone resorption around 902 pedicle screws was analyzed in post-operative, and follow-up radiographs obtained from 156 patients who underwent pedicle screw plate fixation. To determine the resorption degree, categorized arbitrarily as grade 1 (less than 1 mm), grade 2 (1 mm or more, but less than 2 mm), or grade 3 (2 mm or more), the width of radiolucent zones was measured. In 39 patients in whom resorption was graded 1, 2, or 3, the pattern of progression of 78 screws was evaluated. Results: Resorption occurred around 78 (8.6%) screws in 39 (25%) patients, 26 of whom had more than one lesion. For 99% of screws, there was evidance of resorption within 12 weeks of pedicle screw plate fixation. During follow-up, 61.5% of screws (48/78) remained stable, while 38.5% (30 screws) showed progression to higher grades. The possibility of progression to a higher grade is less when the initial grade is lower. Conclusion: An understanding of the radiographic patterns of bone resorption is useful for monitoring a patient after pedicle screw plate fixation.

4:25 Repair of osteoporotic vertebral compression fracture by transpedicular injection of bioactive calcium phosphate cement into the vertebral body

Purpose of study: Percutaneous vertebroplasty (VP) and kyphoplasty (KP) have been successfully used for the treatment of osteoporotic vertebral compression fractures (VCFs). Although polymethylmethacrylate has been exclusively used and seems to be useful in the clinical series of VP and KP, it seems not to be an optimal material because of several potential disadvantages. We have developed transpedicular injection of bioactive calcium phosphate cement (CPC) into the vertebral body for repair of osteoporotic VCFs and pseudarthrosis without neurological involvements. We report the clinical experience of this new treatment for painful VCFs.Methods used: We prospectively followed up 38 patients with 41 vertebrae treated with this procedure, including 19 fresh fractures, 3 delayed unions and 19 vertebral pseudarthroses. The average age of the patients was 71 years old, and the follow-up period was 15 months on average (3 to 70 months). Radiological examinations are performed for all patients to evaluate progression of collapse, radiolucent line around the CPC, vertebral height change at flexion-extension lateral views. Wedging rate is defined as a percentage of the anterior vertebral height to the posterior one in a lateral view and is evaluated in all patients before and after the surgery and at final follow up. Preoperative and postoperative pain was assessed using a 10-point scale.of findings: All patients had significant pain relief. The average 10-point pain scale was 8.4 preoperatively and improved to 0.9 postoperatively. Radiological examinations 3 months after treatment to the final follow-up demonstrated no progression of vertebral collapse, no radiolucent zone around the CPC and also no detectable changes of the vertebral height at flexion-extension views in all cases of fresh VCFs and delayed union, and in 18 of 19 vertebrae of pseudarthrosis. In case of fresh fracture, the wedging rate is 66% before treatment and 84% immediately after treatment. Seventy-nine percent were maintained up to the final follow-up at 30 months after surgery. No loss of correction was observed after 1 month. As for pseudarthrosis, the rate is 28% preoperatively, 61% postoperatively and 49% at final follow-up of 13 months after surgery. The correction loss, which is not associated with back pain, occurred within 3 months postoperatively, but afterward never. Two patients had asymptomatic complications. One was minor intracanal leak, and the other was extravertebral migration of fragmented CPC 1 month after surgery, which suggested the failure of repair. There were no other significant complications in this series.Relationship between findings and existing knowledge: The CPC we used is injectable, nonexothermic, self-setting, is bioactive cement with osteoconductivity and sets by hydration to change composition into carbonated hydroxyapatite. Direct bonding of CPC to the surrounding bone and new bone formation around the CPC were described in the literature. Its compressive strength increases over time and reaches the maximum in about 7 days after injection. The maximum value is over 80 MPa, which is strong enough to reinforce the collapsed vertebrae. The clinical and radiological outcomes in this study suggest that the fractures have been successfully repaired by the injection of the CPC, except one case of pseudarthrosis.Overall significance of findings: The transpedicular injection of CPC is safe and effective for pain relief and stabilization of the fractured vertebral body and might have potential advantages over the VP and KP because of the excellent biocompatibility of the CPC.Disclosures: Device or drug: calcium phosphate cement: Biopex, Mitsubishi Materials Corporation, Tokyo, Japan. Status: not approved.Conflict of interest: No conflicts.

Hydroxyapatite coating improves fixation of pedicle screws

We investigated the effects of hydroxyapatite (HA) coating on the purchase of pedicle screws. A total of 23 consecutive patients undergoing lumbar fusion was randomly assigned to one of three treatment groups. The first received uncoated stainless-steel screws, the second screws which were partly coated with HA, and the third screws which were fully coated. The insertion torque was recorded. After 11 to 16 months, 21 screws had been extracted. The extraction torque was recorded. Radiographs were taken to assess fusion and to detect loosening of the screws. At removal, the extraction torques exceeded the upper limit of the torque wrench (600 Ncm) for many HA-coated screws. The calculated mean extraction torque was 29 ± 36 Ncm for the uncoated group, 447 ± 114 Ncm for the partly-coated group and 574 ± 52 Ncm for the fully-coated group. There were significant differences between all three groups (p &lt; 0.001). There were more radiolucent zones surrounding the uncoated screws than the HA-coated screws (p &lt; 0.001). HA coating of pedicle screws resulted in improved fixation with reduced risk of loosening of the screws.

Complications associated with bone cementing for the treatment of giant cell tumors of bone

A retrospective review was conducted of giant cell tumors treated between 1984 and 1998 using the technique of aggressive curettage through a large bone window followed by acrylic cement reconstruction. Fifteen patients with a mean follow-up time of 46 months (range, 24–188 months) were identified. One patient had a local recurrence 24 months postoperatively. All the patients showed a radiolucent zone at the bone–cement interface up to 2.5mm in width during the first 6 months after operation. However, the radiolucent zones were nonprogressive and did not affect the stability of the bone cement. Osteoarthritis of the knee joint occurred 14 years postoperatively in one patient with an intraarticular fracture at presentation. A stress fracture occurred in one patient who had the largest tumor in the distal femur. Acrylic cement reconstruction is a safe and effective procedure that provides local adjuvant therapy. Giant cell tumors with an associated intraarticular fracture remain a challenging problem to treat.

当科における人工肩関節置換術の術後成績

We investigated the clinical results of total shoulder replacement and performed a radiological evaluation. Total shoulder replacement was performed on 6 shoulders with osteoarthritis and on 4 shoulders with rheumatoid arthritis. JOA score was determined pre- and post-operatively.The patients consisted of 3 males and 5 females, and the age at operation averaged 69 years for osteoarthritis and 64 for rheumatoid arthritis. The average follow-up period was 36 months (minimum follow-up: 12 months). The post-operative JOA score of the osteoarthritic shoulder was significantly higher than pre-operative, especially for pain score and range of motion score. In the rheumatoid arthritic shoulder, post-operative pain score was significantly higher than pre-operative, although there was no statistically significant difference between the pre- and post-operative JOA scores.Radiological evaluation was performed according to Brenner's classification. Radiolucent zones of one millimeter or less were seen in 6 cases around the glenoid component and the proximal half of the humeral component, and were not seen in the distal half of the humeral component. However, loosening was not noted in both components. Two rheumatoid patients demonstrated subluxation of the glenoid component and 1 case showed a broken glenoid component. Only 1 case was found with radiolucent line around the proximal humeral component.Our results revealed that total shoulder replacement provides effective pain relief and recovery of the range of motion in osteoarthritis, and pain relief in rheumatoid arthritis.

Anterior cervical fusion using porous hydroxyapatite ceramics for cervical disc herniation: a two-year follow-up

Background context: The Smith-Robinson Method (SR), which employs autogenous bone, is the current standard for anterior cervical fusion (AF) surgery. However, autogenous bone has graft-related complications and morbidity, and harvesting it increases trauma and risk to the patient. The use of hydroxyapatite ceramic (HAP) inserts may provide a superior alternative. Purpose: To determine the efficacy of using HAP in AF. Study design/setting: A retrospective study of patients who had AF surgery with wide decompression and porous HAP inserts used to treat cervical disc herniation (CHD). Patient sample: We evaluated 36 patients who had single-level AF using HAP for CHD, without internal fixations, clinically and radiographically with a minimum follow-up of 2 years. There were 25 men and 11 women, with an average age of 49 years (age range, 24–78 years). Preoperative diagnosis included 25 cases with myelopathy and 11 cases with radiculopathy. Outcome measures: We established four grades to classify the degree of bony fusion between the HAP and vertebra, based on any motion at the fused segment, any radiolucent zones (RZ) between vertebral bodies and the grafted HAP, and anterior or posterior bone formations on grafted HAPs. We evaluated the severity of myelopathy by applying the Japan Orthopaedic Association (JOA) scoring system. We evaluated the surgical outcome of the myelopathy patients using the Hirabayashi recovery rating, and for the radiculopathy patients, we used the Herkowitz criteria. Methods: We retrospectively reviewed the radiographic and clinical records of all 36 patients from surgery up to periods ranging from 2 to 7 years after surgery, with the average period of follow-up being 4.5 years. We systematically classified the degree of bony fusion into four grades ranging from Grade 1 nonunion to Grade 4 complete union. Results: None of the subjects showed Grades 1 and 2 fusion. Eleven percent of the cases showed Grade 3 and 89% showed Grade 4. Loss of height of the fused segment was observed in 29 cases with an average of 1.6 mm. A decrease of lordotic angle of the fused segment was observed in six cases with an average of 2.3 degrees. Four cases revealed cracked HAP inserts but achieved Grade 4 bone fusion. There was no evidence of collapse or displacement of HAPs. The results of the 11 radiculopathy patients were excellent in 10 cases and good in the remaining case. The recovery rate of the 25 myelopathy patients was 73.0%. Conclusions: Our method of anterior cervical fusion surgery using porous HAP inserted into resected end plates, combined with a wide decompression procedure, had clinical and radiographic results so satisfactory that we conclude that it can effectively replace the use of autogenous bone for treating cervical disc herniation.

What's new in orthopaedic research.

The last year has brought substantial advances in many areas of orthopaedic research. Probably the most impressive is the shift from a focus on implant design, obviously the most successful treatment of end-stage degenerative joint disease, to the potential for earlier interventions, or solutions, that could increase the life of the cartilage, bone, tendons, and ligaments of the joint. The search for biological solutions touches on all aspects of orthopaedic research: response to implant materials, development of tissue-engineered cartilage and bone, and discovery of biomarkers for joint disease. We will review some of the latest advances made and questions raised in this new age of orthopaedic research. This year's combined Orthopaedic Research Society/American Academy of Orthopaedic Surgeons symposium dealt with clinical, engineering, and biological issues related to implant wear. This symposium complemented a recent publication by the Academy and the National Institutes of Health on implant wear1. The manifestations of wear of total hip and knee replacements have been well documented in the past decade. Most commonly, osteolysis progresses in a slow, linear fashion and is not detectable radiographically until five years or more postoperatively, when periprosthetic radiolucent zones may be observed. Rates of osteolysis as high as 60% have been reported in association with certain hip implants2. In addition to wear of hip and knee replacements, wear of total shoulder and elbow replacements is an emerging problem that should be carefully monitored in the future. ### Biological Aspects of Wear-Osteolysis Particle-induced osteolysis is a primary cause of aseptic loosening. A consensus has emerged that the predominant process is one of cytokine production in response to phagocytosis of implant wear particles resulting in increased proliferation and differentiation of osteoclast precursors into mature osteoclasts. Several cell types, including macrophages, fibroblasts, and osteoblasts, observed in periprosthetic tissues are believed to play a …

Anomalies of ossification in the posterolateral femoral condyle: assessment by MRI

Anomalies of ossification in the lower femoral epiphysis are often radiographically indistinguishable from juvenile osteochondritis dissecans. To clarify the MRI characteristics of the anomalies of ossification in the posterolateral femoral condyle that distinguish it from juvenile osteochondritis dissecans. We retrospectively examined the medical records, plain radiographs (n = 4), MRI (n = 4) and follow-up MRI (n = 2) of four boys (age 8-11 years) with anomalies of ossification in the posterolateral femoral condyle. Plain radiography showed symmetrical marginal irregularity of the posterolateral femoral condyles of both knees. These lesions were asymptomatic, and the areas of irregular radiographic appearances reduced in size or disappeared without treatment within a mean observation period of 3.5 months. MRI showed a clearly demarcated low-intensity islet with the same signal intensity as subchondral bone (which was considered to be an accessory ossification nucleus) in a high-signal area in which the signal intensity was equal to that of normal articular cartilage. The areas observed as radiolucent zones on plain radiography were visualised at the same signal intensity as articular cartilage, and were continuous with articular cartilage on MRI; thus they were regarded as uncalcified cartilage. These MR findings are different from MR images of osteochondritis dissecans. MRI is considered to be the most effective non-invasive diagnostic method for these two conditions.

Autogenous bone peg fixation for osteochondritis dissecans of the elbow

Restoration of pain-free elbow function and prevention of osteoarthritis in patients with osteochondritis dissecans treated with autogenous bone peg fixation. Radiolucent types of osteochondritis and types with zone of demarcation after unsuccessful conservative treatment lasting at least 6 months. Persistence of radiolucent zone or demarcated fragment after previous removal of dissecans fragment. Advanced demarcated fragment almost separated; here early surgery is indicated. Complete separation of dissecans fragment with subchondral sclerosis. Fragmented dissecans fragment. Lateral approach, exposure of capitulum humeri, removal of free bodies if present, drilling of 2.5-mm hole through dissecans fragment and insertion of bone peg harvested from crest of the ulna. Two pegs are used for large fragments. Report of 32 patients (all men, average age 14.8 years, average period of follow-up 5.9 years). Results in 20 patients who underwent a bone peg fixation with or without removal of free bodies were compared to those observed in 12 patients who were either treated conservatively or had only a removal of a free body. The gain in the range of motion, the decrease in pain and the radiologic appearance were superior in the bone peg group.