Radiographic Evidence Of Osteolysis Research Articles

Uncemented total hip arthroplasty using alumina ceramic bearings at a minimum of 14years of follow-up.

The effectiveness of modern ceramic bearings has been well established in reducing the osteolysis associated with wear of the bearing surfaces in total hip arthroplasty (THA). However, there are limited mid- to long-term follow-up data for complications associated with ceramic bearings. This case series analyzed 124 consecutive primary uncemented THAs in 108 patients with a mean age of 61years using alumina ceramic-on-alumina ceramic bearing couples. Seventy THAs (56%) were evaluated at a minimum 14years of follow-up; the mean follow-up period was 16 ± 1years (14-20years). Kaplan-Meier survivorship was determined with revision surgery for any reason as the end point. Complications were recorded focusing on osteolysis, ceramic fracture, and abnormal sounds until the final follow-up. Clinical data were scored according to the Merle d'Aubigne and Postel hip score at 14years after THA. The survivorship was 93.5% (95% CI 86.7-97.0%) at 14-years postoperatively. Five patients (4.0%) underwent revision surgery due to instability or infection before 1-year postoperatively. Two patients (1.6%) underwent revision surgery due to ceramic liner fracture at 9- and 12-years postoperatively, respectively. There was no radiographic evidence of osteolysis. A total of 27 complications occurred: dislocations (n = 7/124), squeaking sounds (n = 3/124), clicking sounds (n = 6/124), ceramic liner fractures (n = 2/124), periprosthetic fractures (n = 4/124), deep infections (n = 2/124), transient sciatic nerve palsy (n = 2/124), and femoral stem breakage (n = 1/124). The Merle d'Aubigne and Postel hip score was 16.8 ± 1.4 points. The survivorship analysis demonstrates the uncemented THA using alumina ceramic bearings may provide favorable clinical outcome and can offer minimal wear at a minimum 14-year follow-up. Revision surgery was mostly required due to instability and infection in the short-term, and implant breakage in the mid- to long-term.

High survivorship of highly cross-linked polyethylene in revision Total hip Arthroplasty: a minimum 10-year follow-up study

PurposeHighly cross-linked polyethylene has been introduced to decrease osteolysis secondary to polyethylene wear debris generation. However, few long-term data on revision total hip arthroplasty (THA) using highly cross-linked polyethylene liners are available. The objective of this study was to determine long-term outcomes of a highly cross-linked polyethylene liner in revision THA.Materials & methodsWe evaluated 63 revision THAs performed in 63 patients using a highly cross-linked polyethylene liner between April 2000 and February 2005. Of these, nine died and four were lost to follow-up. Thus, the final study cohort consisted of 50 patients (50 hips), including 26 males and 24 females with a mean age of 53 years (range, 27–75 years). Mean follow-up was 11 years (range, 10–14 years).ResultsThe mean Harris hip score improved from 44 points preoperatively to 85 points at the final follow-up. No radiographic evidence of osteolysis was found in any hip. The mean rate of polyethylene liner wear was 0.029 mm/year (range, 0.003 to 0.098 mm/year). A total of 5 hips (10%) required re-revision arthroplasty, including one cup loosening, one recurrent dislocation, and three deep infections. Kaplan-Meier survivorship with an end point of re-revision for any reason was 91.1% and for aseptic cup loosening was 97.9% at 11 years.ConclusionAt a minimum of 10 years, the highly cross-linked polyethylene liners showed excellent clinical performance and implant survivorship, and were not associated with osteolysis in our patients with revision THAs.

Comparison of ceramic-on-ceramic bearing vs ceramic-on-highly cross-linked polyethylene-bearing surfaces in total hip arthroplasty for avascular necrosis of femoral head: a prospective cohort study with a mid-term follow-up

BackgroundThe ideal bearing surface for patients of avascular necrosis (AVN) undergoing total hip arthroplasty (THA) remains controversial. The purpose of this study is to evaluate the clinical outcomes, health-related quality of life (HRQL), and wear of the bearing surface between ceramic-on-ceramic (CoC) and ceramic-on-highly cross-linked polyethylene (CoXPE) THA for patients of AVN after midterm follow-up.MethodsWe performed a retrospective case-control analysis of 93 CoC and 77 CoXPE consecutive THAs for patients of AVN. The cases were followed at a minimum 5 years follow-up (average 7 years). Harris hip score (HHS) score and bearing-related complications were assessed. The health-related quality of life (HRQL) was assessed with the Short Form 36 (SF-36). Plain radiographs and computed tomography (CT) were used for radiographic evaluation.ResultsBoth the CoC group and CoXPE group showed statistically significant improvements in HHS scores with no difference between the two bearing surfaces. There was no significant difference as for SF-36 at the latest follow-up between two groups, except for significant higher scores in the dimensions of general health in the CoC group (75.7 vs 64.7, P = 0.032). No radiographic evidence of osteolysis and loosening was present at the final follow-up. The mean wear rate of the CoC was 0.0096 mm/year and the CoXPE was 0.047 mm/year after evaluation with reconstructed CT.ConclusionsCoC THAs acts as well as CoXPE THAs for patients with femoral head avascular necrosis after midterm follow-up. CoC bearing can significantly decrease the wearing rate than CoXPE bearing.

Total Hip Arthroplasty in Patients 21 Years and Younger Using Highly Cross-Linked Polyethylene: Excellent Survivorship at Five Years

AbstractThe survivorship of contemporary total hip arthroplasty has improved substantially as a result of the success of highly cross-linked polyethylene. Nevertheless, there is limited information on its performance in extremely young patients. The purpose of this study is to evaluate the (1) clinical and radiographic outcomes, (2) polyethylene wear rates, and (3) mid-term survivorship of total hip arthroplasty in patients 21 years or younger using highly cross-linked polyethylene. After Institutional Review Board approval, the authors identified 45 patients aged 21 years or younger (56 hips) who underwent primary total hip arthroplasty with highly cross-linked polyethylene at their institution by the senior author between 2000 and 2009. Patients were followed for a minimum of 2 years, or until revision. At a mean follow-up of 57 months, modified Harris Hip Scores, Western Ontario McMaster Universities Arthritis Index scores, Short Form-12 physical function scores, and University of California, Los Angeles activity scores improved significantly in all patients. There was no radiographic evidence of osteolysis in any patient. The mean linear polyethylene wear rate was 0.02 mm per year. Survivorship was 98% with one revision for acetabular loosening at 71 months. Total hip arthroplasty in patients 21 years or younger with highly cross-linked polyethylene had excellent clinical and radiographic outcomes at mid-term follow-up. Longer-term data are needed in this patient population to confirm continued survivorship in the extremely young. The level of evidence used for this study was level III.

Clinical Outcomes and Bearing-Specific Complications Following Fourth-Generation Alumina Ceramic-on-Ceramic Total Hip Arthroplasty: A Single-Surgeon Series of 749 Hips at a Minimum of 5-Year Follow-Up

BackgroundThe purpose of this study is to evaluate the minimum 5-year outcomes and bearing-specific complications in a single surgeon series of fourth-generation alumina ceramic-on-ceramic total hip arthroplasties (THAs). MethodsWe retrospectively analyzed 667 patients (749 hips) who underwent primary THAs by a single surgeon using fourth-generation alumina ceramic bearings. There were 315 men and 352 women with a mean age of 54.2 years. The surgeon used cementless prostheses with an identical design and BIOLOX Delta ceramics in all hips, using a 36-mm head in 472 hips (63%) and a 32-mm head in 227. The mean follow-up duration was 6.5 years (range, 5 to 8 years). ResultsThe mean Harris hip score improved from 45.6 points preoperatively to 91.3 points at final follow-up. All but 1 acetabular cup and all femoral stems were well fixed. No radiographic evidence of osteolysis was identified at final follow-up. There were 2 (0.3%) ceramic liner fractures and no ceramic head fractures. A total of 48 hips (6.4%) exhibited audible noise (29 clickings and 19 squeakings), but no patient required revision. Other complications were 1 dislocation, 1 deep infection, 3 iliopsoas tendonitis, and 6 periprosthetic femoral fractures. Kaplan-Meier survivorship for revision for any reason was 98.6% (95% confidence interval, 97.7-99.5) at 6.5 years. ConclusionDelta ceramic-on-ceramic THAs had a high rate of survivorship without radiographic evidence of osteolysis at 6.5-year follow-up. However, we found 0.3% ceramic liner fractures and 6.4% audible noises associated with the use of Delta ceramics.

The result of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a polyethylene liner.

BackgroundWear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition.MethodsTwenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated.ResultsThe median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively.ConclusionsThe survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low.

Metallic wear debris may regulate CXCR4 expression in vitro and in vivo.

CXCR4, the chemokine receptor for CXCL12, also known as SDF-1 (stromal cell derived factor-1), has been shown to play a pivotal role in bone metastasis, inflammatory, and autoimmune conditions but has not been investigated in periprosthetic osteolysis. We co-cultured osteoblast-like cells with increasing concentrations of metallic (Co-35Ni-20Cr-10Mo and Co-28Cr-6Mo) and Co-ions simulating wear debris. Real-time polymerase chain reaction (RT-PCR) and Western blotting were used to quantify gene and protein expression of CXCR4. The expression of tumor necrosis factor-alpha (TNF-α) and the effects of AMD3100 (bicyclam) on both CXCR4 and TNF-α expression among these cells was investigated. RT-PCR showed an increase in CXCR4 mRNA (7.5-fold for MG63 and 4.0-fold for SaOs-2 cells) among cells co-cultured with metal alloy particles. Western blotting showed a time-dependent increase in protein expression of CXCR4. The attempted blockade of CXCR4 by its known competitive receptor agonist AMD3100 led to a significant inhibition TNF-α mRNA expression. Immunohistochemistry showed CXCR4 positivity among patients with failed metal-on-metal hip replacements and radiographic evidence of osteolysis. Our data collectively suggest that the CXCR4 chemokine is upregulated in a dose- and time-dependent manner in the presence of metallic wear debris.

Total Hip Arthroplasty Using Highly Cross-Linked Polyethylene in Patients Younger Than 50 Years With Minimum 10-Year Follow-Up

The purpose of this study was to investigate the relatively long-term outcomes in 50 patients (54 hips) younger than 50years of age who underwent total hip arthroplasty using highly cross-linked polyethylene (HXLPE) liners. With a minimum follow-up of 10years, mean age at time of surgery was 38.9years (range, 15–50years). Survivorship was 100%. There was no radiographic evidence of osteolysis or component loosening. Mean steady-state femoral head penetration rate was 0.020±0.0047mm/yr. Clinical outcomes were excellent, with mean Harris hip score of 91.2 (range, 72–99) points at final follow-up.

Revision Total Hip Arthroplasty Using an Alumina-On-Alumina Bearing Surface in Patients With Osteolysis

We evaluated the outcomes of 64 consecutive revision total hip arthroplasties with an alumina-on-alumina bearing surface in 61 patients with osteolysis. No implants had been rerevised nor was osteolysis detected at a mean of 9.8 years (range, 7.0-13.1 years) postoperatively. There was 1 case of stem loosening but no cup loosening or alumina bearing fractures. Two surgical procedures were performed for an infection in 1 patient. Three dislocations occurred in 3 hips; all were treated with closed reduction and abduction bracing for 3 months. No further dislocations occurred. With any reoperation or radiographic evidence of osteolysis or loosening as the end point, the 7-year survival rate was 96.9% (95% confidence interval, 90.8%-100%). The alumina-on-alumina bearing surfaces used for revision total hip arthroplasty in patients with osteolysis were found to produce encouraging clinical results and implant survival rates at a minimum of 7 years postoperatively.

Alumina-on-alumina THA Performed in Patients Younger Than 30 Years: A 10-year Minimum Followup Study

THA in patients younger than 30 years presents challenges because of uncertainties regarding the long-term survivorship of prostheses. Alumina-on-alumina bearings, which exhibit little long-term wear, may be a reasonable option but the long-term survivorship is unknown. We determined (1) the survival rate of alumina-on-alumina bearings in patients younger than 30 years after a 10-year followup, (2) the incidence of audible hip clicking and squeaking, (3) radiographic evidence of osteolysis, and (4) the effects on pregnancy, childbirth, and career choice. We retrospectively reviewed 62 patients who had 75 THAs with alumina-on-alumina bearings followed more than 10 years (average, 11.5; range, 10-13.5 years). Mean patient age at the time of surgery was 24 years (range, 18-30 years). All operations were performed using the same cementless implant at a single center. We determined survival, presence of osteolysis, and function (Harris hip score, WOMAC). The 10-year survival rate of alumina-on-alumina bearings in THAs, with revision for any reason as the end point, was 98.9%. Audible hip clicking and squeaking were identified in 10 hips and two hips, respectively. No osteolysis was detected. None of the 11 patients who became pregnant had been affected by their THA during pregnancy or childbirth. Seven of the 14 patients who were unemployed at the time of index surgery stated that their THA affected their job choice. We found a high 10-year survival of cementless alumina-on-alumina bearings in THAs in patients younger than 30 years. Lifetime events such as job choice, pregnancy, and childbirth should be considered when choosing THA for patients younger than 30 years. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Preliminary Clinical and Radiographic Results of Large Ceramic Heads on Highly Cross-Linked Polyethylene

Data are limited regarding large ceramic femoral heads with highly cross-linked polyethylene. We hypothesized that large ceramic head articulation with highly cross-linked polyethylene is safe with a low wear rate, comparable to metal-on-highly cross-linked polyethylene.The study group comprised 63 patients (72 hips) who had undergone total hip replacement (THR) with ceramic-on-highly cross-linked polyethylene between April 2006 and March 2007 with a minimum 2-year follow-up. Postoperative Western Ontario and Mc-Master Universities Arthritis Index (WOMAC) and Hospital for Special Surgery (HSS) scores were used for clinical assessment. Six-week and 2-year radiographs were analyzed by 2 independent observers using Roman 1.70 software. Twenty-six patients (29 hips) had 32-mm and 37 patients (43 hips) had 36-mm Biolox delta ceramic femoral heads (Ceramtec, Plochingen, Germany). Mean patient age was 60.9 ± 8.9 years, and mean follow-up was 2.9 ± 0.5 years. Mean postoperative WOMAC and HSS hip scores were 30.4 and 36.6, respectively. Mean wear at 1 and 2 years postoperatively was 0.06 ± 0.28 and 0.006 ± 0.12 mm/yr for all hips, respectively. Mean wear at 1 and 2 years postoperatively for the 32-mm femoral head was 0.063 ± 0.278 and 0.007 ± 0.126 mm/yr, respectively, and for the 36-mm femoral head was 0.057 ± 0.292 and 0.006 ± 0.118 mm/yr, respectively. No patient had any clinical complications, such as reoperation, infection, fractures, or radiographic evidence of osteolysis or loosening. The early results of THR with large ceramic heads demonstrate high safety and efficacy. Our data with 2-year follow-up show low wear rates, similar to published data for metal-on-highly cross-linked polyethylene.

The Bioknotless Suture Anchor For The Treatment Of Shoulder Instability: Clinical Results

PURPOSE: Arthroscopic treatment of symptomatic shoulder instability has become a well accepted procedure. Knotless suture anchors are one type of implant utilized for capsulolabral repair and have several advantages compared to other available devices. The use of these anchors, however, has been associated with unfavorable outcomes. The purpose of this study is to report our results of arthroscopically treated shoulder instability with a knotless, bioabsorbable suture anchor. METHODS: We identified and contacted patients who underwent arthroscopic capsulolabral repair of the shoulder with the BioKnotless anchor (DePuy Mitek, Raynam, Massachusetts). All patients had a minimum follow up of 2 years. Patient evaluation included a subjective questionnaire, physical exam, radiographs, and an MRI if indicated. All patients completed validated shoulder and health measurement outcome tools including the Simple Shoulder Test, the Short Form 12 Health Survey (SF-12), and the Western Ontario Shoulder Instability Index (WOSI). RESULTS: Eight patients were evaluated. The mean age was 28.9 years. There were 6 males and 2 females. The mean time to follow up was 33.6 months. No patients had any episodes of recurrent instability. When compared to the contralateral shoulder, patients lost an average of 2.5° of forward flexion, 6.3° of external rotation, and 11.3° of internal rotation. No patients had instability on physical exam as determined by apprehension, relocation or load and shift testing. Radiographic examination revealed no evidence of osteolysis, chondrolysis or degenerative changes. The mean WOSI score was 65.2% (out of 100%). The mean Simple Shoulder Test score was 10.4 (out of 12). The mean physical component to the SF-12 was 51.0 (population mean 52.5) and the mental component was 55.5 (population mean 53.1). CONCLUSIONS: Patients did report some level of disability of the shoulder determined by the WOSI, Simple Shoulder Test, and SF-12 scores. There was no radiographic evidence of osteolysis or glenohumeral arthritis. None of the patients reported any recurrence of instability. When properly utilized, the Bioknotless anchor remains a viable and safe option for successful treating symptomatic shoulder instability.

Polymorphisms in the interleukin‐1 receptor antagonist and interleukin‐6 genes affect risk of osteolysis in patients with total hip arthroplasty

To determine whether osteolysis after total hip arthroplasty (THA) is associated with common polymorphisms within the genes encoding the interleukin-1 (IL-1) family and IL-6, and to determine whether polymorphisms that are associated with osteolysis affect in vitro messenger RNA (mRNA) expression in human peripheral blood mononuclear cells (PBMCs) in response to wear particles. Unrelated white subjects of North European descent (n=612) were recruited a mean of 11 years after cemented THA for primary osteoarthritis. Of these subjects, 272 had previous osteolysis and 340 had no radiographic evidence of osteolysis (control group). Genomic DNA was genotyped for the following single-nucleotide polymorphisms (SNPs): IL1A +4845, IL1B +3954, IL1B -3737, IL1B -511, IL1RA +2018, IL6 -174, IL6 -572, and IL6 -597. In a subset of 60 subjects, PBMCs were extracted and stimulated with titanium particles and/or endotoxin, and cytokine mRNA expression was measured using quantitative real-time reverse transcriptase-polymerase chain reaction. The odds ratio (OR) for osteolysis associated with carriage of the IL1RA +2018C allele was 0.66 (95% confidence interval [95% CI] 0.48-0.91) (P=0.012). The remaining SNPs were not individually associated with osteolysis. The uncommon IL6 haplotype -174G/-572G/-597A (osteolysis group frequency 2.4%, control group frequency 0.8%) was associated with osteolysis (P=0.02, calculated using Haploview software). The IL1RA +2018CC genotype was associated with increased mRNA expression compared with the +2018TT genotype in both unstimulated and stimulated PBMCs (P=0.01 by analysis of variance, after Bonferroni correction). The IL1RA +2018C allele is associated with a decreased risk of osteolysis after THA and with increased IL-1 receptor antagonist mRNA expression in vitro. An uncommon haplotype within the promoter region of the gene for IL-6 is positively associated with osteolysis.

Use of a cementless modular implant for arthroplasty in developmental dysplasia of the hip: Early results

Total hip arthroplasty for osteoarthritis secondary to developmental dysplasia of the hip (DDH) is technically difficult due to the abnormal anatomy involved. Surgery may be facilitated by using a modular femoral prosthesis, which allows intra-operative variations in neck length and version to accommodate final acetabular position. The aim of this study was to assess our early results with the S-ROM hip (DePuy), a cementless modular femoral implant, for arthroplasty in patients with DDH. We performed 22 total hip replacements on 20 patients over a three and a half year period. Ten patients had had previous osteotomies performed, including two of whom had Ganz peri-acetabular osteotomies performed in our centre. Follow-up ranged from 6 to 44 (mean 19.6) months. Harris hip scores improved from an average of 42 points pre-operatively to 90 points post-operatively. No radiographic evidence of osteolysis was seen around the femoral implant. Two patients required revision of their acetabular components. Both had satisfactory outcomes. Our early results with the S-ROM femoral prosthesis correlate well with those from other studies involving arthroplasty for DDH. This implant is extremely versatile and easy to use in this complex patient population.

Use of a cementless modular implant for arthroplasty in developmental dysplasia of the hip: early results

Total hip arthroplasty for osteoarthritis secondary to developmental dysplasia of the hip (DDH) is technically difficult due to the abnormal anatomy involved. Surgery may be facilitated by using a modular femoral prosthesis, which allows intra-operative variations in neck length and version to accommodate final acetabular position. The aim of this study was to assess our early results with the S-ROM hip (DePuy), a cementless modular femoral implant, for arthroplasty in patients with DDH. We performed 22 total hip replacements on 20 patients over a three and a half year period. Ten patients had had previous osteotomies performed, including two of whom had Ganz peri-acetabular osteotomies performed in our centre. Follow-up ranged from 6 to 44 (mean 19.6) months. Harris hip scores improved from an average of 42 points pre-operatively to 90 points post-operatively. No radiographic evidence of osteolysis was seen around the femoral implant. Two patients required revision of their acetabular components. Both had satisfactory outcomes. Our early results with the S-ROM femoral prosthesis correlate well with those from other studies involving arthroplasty for DDH. This implant is extremely versatile and easy to use in this complex patient population.

Osteolysis

Osteolysis is defined as the process of progressive destruction of periprosthetic bony tissue, characterized on serial radiographs as progressive radiolucent lines and/or cavitation at the implant-bone or cement-bone interface. Without proper treatment, osteolysis may progress to aseptic loosening and catastrophic failure of the implant. Osteolysis is a multifactorial process stemming from host, prosthesis, and surgical factors. Billions of submicron wear particles are generated at material interfaces that cause osteolysis. Wear particles are dispersed along the effective joint space, into bone, and throughout the adjacent soft tissues. Initially, patients may have no clinical symptoms despite radiographic evidence of osteolysis and can remain completely asymptomatic, even in the presence of substantial bone loss. Symptoms usually do not occur until the bone loss has reached the point of causing implant loosening, implant failure (fracture), or periprosthetic fracture. Radiographic images and standard examination provide limited information and almost always underestimate the amount of bone loss. Three-dimensional computed tomography is more sensitive and can monitor the volume of the lesion, however the trade-offs are its high cost and radiation exposure. The timing for treatment of periprosthetic osteolysis is controversial and the medical decision-making is debatable. Medical treatment seems to be attractive but there is no proven or approved drug therapy to prevent or inhibit periprosthetic osteolysis. We reviewed the medical and surgical options that are available for treatment of periprosthetic osteolysis.

Bunionette deformity correction with distal chevron osteotomy and single absorbable pin fixation.

Between January 1997 and July 2000, 10 patients with symptomatic bunionette deformity underwent 12 distal fifth metatarsal chevron osteotomies in which an absorbable poly-p-dioxanone suture (PDS) pin was used for fixation. Of the 10 patients, nine were female. Average age at operation was 41 years (range, 23-70). Mean duration of follow-up was 48 months (range, 6-81). All patients obtained clinical and radiographic union by 6 weeks, and there was no radiographic evidence of osteolysis, displacement, or avascular necrosis of the metatarsal head at final follow-up. There were no serious complications. The average postoperative AOFAS score was 93 of 100 possible. All patients were satisfied with the procedure and would have it again. Distal chevron osteotomy with a single, nonpredrilled PDS absorbable pin for the correction of symptomatic bunionette deformity is a reliable and effective technique that provides adequate fixation without complications.

Bone formation and bone resorption in failed total joint arthroplasties: Histomorphometric analysis with histochemical and immunohistochemical technique

To elucidate the reactions of bone around aseptically loosened total joint arthroplasties, 24 interface tissues with adjacent bone were obtained in 17 revision operations (11 hips and six knees). The morphology of the bone surface next to the interface membrane was investigated with histochemical and immunohistochemical techniques and then histomorphometrically analysed. One-third of the total bone surface. 32.69 +/- 5.16% (mean +/- SE) (n = 24), showed positive alkaline phosphatase activity. The bone surface in contact with the cells positive for CD11b (a macrophage marker) amounted to 19.33 +/- 5.16% (n = 24). The proportion of the osteoclastic bone resorption estimated by vitronectin receptor expression was 7.67 +/- 1.82% (n = 21). Tissues retrieved from the sites where radiographic evidence of osteolysis was present (n = 12) had a significantly larger extent of the bone surface in contact with CD11b-positive cells than did the tissues from areas without osteolysis (n = 12, p = 0.0067, Mann-Whitney U test), whereas no significant difference was observed in the extent of osteoclastic bone resorption. These data demonstrate that active bone formation, regarded as a repair process, is the most common feature even in revised cases. They also highlight the role played by macrophages, not as cells producing inflammatory mediators that could activate osteoclasts, but as cells primarily responsible for the bone loss in osteolytic lesions.

Assessment of Antifungal Therapy in an 800-Gram Infant with Candidal Arthritis and Osteomyelitis

A 720-g premature newborn developed disseminated candidiasis during treatment with systemic antibiotics and total parenteral nutrition through an umbilical arterial catheter. Clinical features were typical for candidal skeletal infection at this age and included warmth and fusiform swelling of the lower extremities together with radiographic evidence of osteolysis and cortical bone erosion. Candida albicans was cultured from blood, urine, joint fluid, and a bone aspirate. The infection was cured with a 44-day course of amphotericin B and flucytosine (5-fluorocytosine). Antifungal therapy was monitored closely with serum drug levels and laboratory tests for bone marrow toxicity and renal dysfunction. Serum levels of both drugs were comparable to those achieved in older patients treated with similar doses. Significant concentrations of amphotericin B were detected in serum four and 17 days after completion of therapy, indicating a slow rate of elimination similar to that which occurs in adults. There was no evidence of drug-induced toxicity other than transient elevation in the fractional urinary excretion of sodium. This suggests that antifungal therapy may be effectively and safely administered to infants in dose schedules similar to those used for older patients.