Tissue reactions to particles of bone-substitute materials in intraosseous and heterotopic sites in rats: discrimination of osteoinduction, osteocompatibility, and inflammation.

Two rat models were used to characterize tissue-specific reactions to particles of bone-substitute materials: one for osteocompatibility in a healing tibial wound and the other in a heterotopic, subcutaneous site. Small, unicortical tibial wounds in rats healed spontaneously, beginning with the rapid proliferation of intramedullary woven bone. That temporary bone was resorbed by osteoclasts and finally, the cortical wound was healed with lamellar bone and the medullary space was repopulated with marrow. When various particulate materials were implanted into fresh wounds, three types of reactions were observed. (1) Demineralized bone powder (DBP) and non-resorbable calcium phosphate (nrCP) were incorporated into the reactive medullary and cortical bone. (2) Polymethylmetlhacrylate (PMMA) particles were surrounded with a fibrous layer, but did not impair bone healing. (3) Polyethylene (PE) shards and resorbable calcium phosphates (rCPs) were inflammatory and inhibited osseous repair. Subcutaneous sites showed osteoinductive, fibrotic, or inflammatory responses to these materials. Only DBP induced endochondral osteogenesis subcutaneously. The nrCP evoked a fibrous reaction. In contrast, rCPs, PMMA, and PE shards generated inflammatory reactions with each particle being surrounded by fibrous tissue and large multinucleated giant cells. In conclusion, only DBP showed osteoinductive as well as osteocompatible properties. The nrCP was osteocompatible. The rCPs stimulated various degrees of inflammatory responses. PMMA was osteocompatible and did not interfere with the bone healing process. PE was not osteocompatible and generated foreign body reactions in both sites. Use of the two sites distinguishes osteoinductive, osteocompatible, and inflammatory properties of particles of bone-substitute materials.

Clinically occult avascular necrosis of the hip in systemic lupus erythematosus.

OBJECTIVE: To study the natural history of clinically occult avascular necrosis (AVN) of the hip in patients with systemic lupus erythematosus (SLE). METHODS: Sixty-six patients with SLE (without symptoms referable to the hip) receiving at least 5 mg/day prednisone for > or = 6 months were screened by magnetic resonance imaging (MRI) for AVN of the hip. A complete MRI evaluating class and percentage of femoral head involvement, AP and lateral radiographs of the hips, bone scan, and physical examination were performed for patients with positive MRI. Medical records were reviewed for serologic and clinical variables that might predict AVN. Repeat MRI were obtained at 3, 6, and 12 months to assess possible progression or resolution of the lesion. Patients with negative screening MRI underwent repeat screening after one year to assess the one year incidence rate. RESULTS: Eleven asymptomatic hips (8%) in 8 patients (12%) had MRI documented AVN. The percentage of femoral head involvement ranged from 1 to 46%. One lesion was MRI class B, the remaining lesions were class A. The radiographic stage of 10 hips was stage 1, the MRI class B hip was stage 2. Risk factors for clinically occult AVN included Afro-American origin, Raynaud's phenomenon, migraine headaches, and a maximal corticosteroid dose of at least 30 mg/day. After 12 months, 43 of 58 patients with an initially negative MRI underwent repeat screening examinations; no new lesions were observed. CONCLUSION: Clinically occult AVN of the hip is common in patients with SLE. The short term natural history of these lesions appears stable without spontaneous healing or clinical or radiographic progression. Risk factors for these asymptomatic lesions are similar to the risks for symptomatic AVN and surgical intervention appears not to be indicated in these patients.

Preoperative nutritional status and outcome of elective total hip replacement.

Preoperative malnutrition increases the morbidity rate and length of hospitalization for various types of surgical patients. However, among patients who undergo elective total hip replacement, it is unclear how preoperative nutritional data can be used to detect a high risk subgroup. The purpose of this study was to identify preoperative nutritional factors that could be used to define a subgroup of patients who have undergone elective total hip replacement who are at high risk for poor post-operative outcome. Preoperative nutritional factors were evaluated in 89 consecutive patients who underwent elective total hip replacement. An inverse relationship was found between serum albumin and length of stay. Patients with an albumin level less than 3.9 were twice as likely to require prolonged hospitalization ( > 15 days) when compared with those in whom the albumin level was 3.9 or greater. Complications were related to the preoperative orthopaedic diagnosis of avascular necrosis of the hip. A subgroup of the patients undergoing elective total hip replacement who are at risk for prolonged recovery can be identified preoperatively by using a serum albumin level of less than 3.9 g/dL. The traditional normal range for albumin may be inappropriate for these patients.

Interdigital neuroma. Local cutaneous changes after corticosteroid injection.

Interdigital neuroma was diagnosed in a patient who was treated subsequently with a local corticosteroid injection. Two to 3 weeks after injection, a 2.5 x 1.5-cm area of hyperpigmentation, thinning of the skin, and subcutaneous fat atrophy developed at the site of the injection. Occurrence of these side effects depends on the solubility of the steroid preparation, the dosage, and the anatomic site and depth of the injection. When using local corticosteroid injections to treat interdigital neuromas, the physician should be familiar with the properties and recommended dosage of the given steroid. The injection should be deep enough so that the cortisone solution does not leak into the subcutaneous area. The possibility of skin atrophy and altered pigmentation should be discussed with all patients.

Total hip arthroplasty in beta-thalassemia. Case report and review of the literature.

A 60-year-old man with beta-thalassemia intermedia and degenerative joint disease was successfully treated by total hip arthroplasty. The operation was complicated by severe bleeding associated with marked bone marrow hyperplasia. Despite autologous cell salvage, massive homologous transfusion was required. Special orthopaedic and perioperative complications stem from beta-thalassemia syndromes. Management may be complicated by anemia, medullary hyperplasia, organ dysfunction associated with iron overload, and susceptibility to infection. The orthopaedic manifestations of beta-thalassemia may be mitigated by chronic transfusions.

Unicompartmental versus total knee arthroplasty in the same patient. A comparative study.

The purpose of this study was to compare unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) and more specifically to evaluate the role of the patella in patient preference between UKA and TKA. A group of 23 patients were chosen, each with a UKA in one knee and a TKA in the opposite knee. As a subset of the group, 13 patients were compared who had not had patellar resurfacing on their TKA side (Group A) versus ten patients who had patellar resurfacing (Group B). Each patient had a UKA and TKA performed during the same hospitalization. Each patient's resurfacing was performed by the same surgical team. Moreover, inpatient care and physical therapy for each patient's respective UKA and TKA were the same. Patient evaluation consisted of chart review, joint registry data, and telephone interviews that focused on patient preference regarding pain, stability, "feel," and ability to climb stairs. The 23 patients studied had an average follow-up period of 81 months (range, 38-153 months). There were 14 men and ten women with an average age of 67 years. Preoperative diagnosis was osteoarthritis in 22 patients and rheumatoid arthritis in one patient. Range of motion (ROM) improved from a preoperative mean of 106 degrees to 123 degrees postoperatively on the UKA side. Mean ROM for the Group A TKAs improved from 104 degrees to 109 degrees, whereas the Group B TKAs remained unchanged at 113 degrees. For patients surveyed in Group A, 31% stated that their UKA knee was their better knee overall, 15% stated that their TKA knee was their better knee overall, and 54% could find no difference.(ABSTRACT TRUNCATED AT 250 WORDS)

The Total Condylar III prosthesis in complex knee reconstruction.

Sixty-one Total Condylar III (TC III) prostheses were implanted in 59 patients at the authors' institution between March 1977 and December 1987. Among the knees with adequate clinical and roentgenographic data, the average follow-up period was 6.1 years. There were six primary arthroplasties and 29 revisions in this group. The primary diagnosis was osteoarthrosis in 17 patients, rheumatoid arthritis in 16 patients, and juvenile rheumatoid arthritis in two patients. The knee score improved from 21.9 preoperatively to 73.7 at last follow-up evaluation. Based on the knee score, there were 71% good or excellent results. There were three failures (8.6%). Radiolucent lines were present in at least one component in 71% of patients, but few of these were considered significant. Although rarely needed, the TC III prosthesis has been shown to be a satisfactory and durable solution to complex knee reconstructive problems including severe deformity, ligamentous instability, and bone loss.