Is Pseudo-Patella Baja Really a Serious Complication of Total Knee Arthroplasty?

BACKGROUND: The available evidence on pseudo-patella baja (PPB) is limited. The purpose of this study is to investigate prospectively the occurrence of PPB after primary total knee arthroplasty and its clinical consequences in a large series of patients with a minimum follow-up of 2 years. PPB was defined as a patella distally displaced in relationship to the femoral trochlea with absence of patellar tendon shortening (Grelsamer RP. J Arthroplasty 2002;17:66-69) due to elevation of the joint line. METHODS: This study is a prospective case series of 354 patients with a mean age of 71.7 (range 52-87) years. Clinical evaluation was performed by the Knee Society Scores (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short-Form 12-item (SF12), and range of motion. Patellar height was assessed by the Insall-Salvati and Blackburne-Peel ratios. RESULTS: The mean follow-up was 3.6 (range 2.0-6.6) years. Postoperatively, 286 (80.7%) patients had a normal patellar height, 17 (4.8%) had true patella baja (TPB), and 51 (14.4%) had PPB. There were no significant differences between the 3 groups in mean KSS-function (P = .107), range of motion (P = .408), WOMAC-pain (P = .095), WOMAC-stiffness (P = .279), or SF12-mental (P = .363). Between normal and PPB groups, there were no significant differences in mean KSS-knee (P = .903), WOMAC-function (P = .294), or SF12-physical (P = .940). However, the TPB group had significantly lower mean KSS-knee (P = .031), WOMAC-function (P = .018), and SF12-physical (P = .005) as compared with either 2 other groups. CONCLUSION: PPB was a relatively common finding, but no significant differences in terms of clinical outcomes were found as compared to patients with postoperative normal patellar height. TPB was infrequent, but these patients had significantly worse clinical outcomes than those with PPB or normal patellar height.

Femoral Expandable Prosthesis In Bone Tumor of an Adult: A Case Report.

Management of bone tumors of the limbs is still a field to be explored. The problems to be faced are diff erent, especially when the lower limbs are the point of interest, due to the diff erent leg length residual. A possible solution, provided by new technologies, is the use of electromagnetic expandable prosthesis. This device is successfully used in the management of paediatric malignant bone tumors. The strength of this prosthesis is the possibility to assist the musculoskeletal growth in children. To our acknowledge review of literature points out only few cases in which this mechanism is used in adult population. The authors present their results with expandable endoprosthetic replacement in an adult patient with severe lower limb discrepancy which occurred after a malignant bone tumor of the knee, obtaining a recovery of approximately 6 cm.

Total hip arthroplasty by using a cementless ultrashort stem: a subject-specific finite element analysis for a young patient clinical case.

In this article, a subject-specific finite element analysis has been developed to study a clinical case of a surgically misaligned hip prosthesis with an ultrashort stem. It was set out to study the strain energy density pattern, comparing the results obtained with computed tomography images. The authors developed two other numerical models: the first one analyzes the stress and strain distributions in the healthy femur (without prosthesis) and the second one analyzes the same boneimplant biomechanical system of the clinical case but assuming the prosthesis in the proper position. The misaligned prosthesis produced an overload at the proximal posterior plane of the femur, as confirmed by computed tomography images, which detect the formation of new bone. The numerical model of the correctly positioned prosthesis demonstrated that the bone is not overloaded and that the position of neutral axis does not significantly shift from the physiological condition.

Does lactoferrin behave as an immunohistochemical oncofetal marker in bone and cartilage human neoplasms?

By immunohistochemistry, lactoferrin (LF) has been extensively investigated in human neoplastic tissues; moreover, LF is able to promote bone growth in a murine model. Until now, no systematic studies on human osteocartilagineous fetal samples have been performed in comparison to corresponding neoplastic specimens to verify if LF may represent an oncofetal marker in this field of pathology. By a monoclonal antibody (clone 1A1; Biodesign International; w.d. 1:75) the distribution pattern of LF in bones of 25 human fetal tissues (8-34 gestation weeks), 10 adults (47-82 years) and 30 cartilage as well as 27 bone tumours (9-76 years) was analyzed. LF was encountered in 23/57 cases of osteocartilagineous tumors and namely in 10/10 giant cell tumours, 5/7 osteoid osteomas, 3/3 chondroblastomas, 3/3 chondromyxoid fibromas, 1/1 myeloma, 1/1 adamantinoma. No LF immunoexpression was detected in osteosarcomas, chondrosarcomas, ossifying fibromas, osteochondroma and enchondromas. In embryo-fetal tissues, LF immunoreactivity was localized in mesenchymal cells as well as in chondroblasts at the 8th gestational week and in immature osteocytes and osteoblasts up to the 18th gestation week, with a considerable decrease by the 24th week. No LF expression was found in any bone district since the 30th and up to the 34th week of gestation as well as in corresponding adult samples. Our findings indicate a role for LF as a bone growth regulator in the early phases of the human endochondral ossification, although the hypothesis of LF as oncofetal marker appears questionable in bone tumours.

Supra-acetabular brown tumor due to primary hyperparathyroidism associated with chronic renal failure.

A 63-year-old woman presented to the Orthopedic Unit of our hospital complaining of right hip pain of 6 months' duration associated with a worsening limp. Her past medical history included chronic renal insufficiency. Physical examination revealed deep pain in the iliac region and severe restriction of the right hip's articular function in the maximum degrees of range of motion. X-rays and CT scan detected an osteolytic and expansive lesion of the right supra-acetabular region with structural reabsorption of the right iliac wing. 99mTc-MDP whole-body bone scan showed an abnormal uptake in the right iliac region. Bone biopsy revealed an osteolytic lesion with multinucleated giant cells, indicating a brown tumor. Serum intact PTH was elevated (1020 pg/ml; normal values, 12-62 pg/ml), but her serum calcium was normal (total=9.4 mg/dl, nv 8.5-10.5; ionized=5.0 mg/dl, nv 4.2-5.4) due to the coexistence of chronic renal failure. 99mTc-MIBI scintigraphy revealed a single focus of sestamibi accumulation in the left retrosternal location, which turned out to be an intrathoracic parathyroid adenoma at surgical exploration. After surgical removal of the parathyroid adenoma, PTH levels decreased to 212 pg/ml. Three months after parathyroidectomy, the imaging studies showed complete recovery of the osteolytic lesion, thus avoiding any orthopedic surgery. This case is noteworthy because (1) primary hyperparathyroidism was not suspected due to the normocalcemia, likely attributable to the coexistence of chronic renal failure; and (2) it was associated with a brown tumor of unusual location (right supra-acetabular region).

Neoadjuvant multidrug chemotherapy including high-dose methotrexate modifies VEGF expression in osteosarcoma: an immunohistochemical analysis.

BACKGROUND: Angiogenesis plays a role in the progression of osteosarcoma, as well as in other mesenchymal tumors and carcinomas, and it is most commonly assessed by vascular endothelial growth factor (VEGF) expression or tumor CD31-positive microvessel density (MVD). Tumor VEGF expression is predictive of poor prognosis, and chemotherapy can affect the selection of angiogenic pattern. The aim of the study was to investigate the clinical and prognostic significance of VEGF and CD31 in osteosarcoma, both at diagnosis and after neoadjuvant chemotherapy, in order to identify a potential role of chemotherapy in angiogenic phenotype. METHODS: A retrospective analysis was performed on 16 patients with high grade osteosarcoma. In each case archival pre-treatment biopsy tissue and post-chemotherapy tumor specimens were immunohistochemically stained against CD31 and VEGF, as markers of angiogenic proliferation both in newly diagnosed primary osteosarcoma and after multidrug chemotherapy including high-dose methotrexate (HDMTX). The correlation between clinicopathological parameters and the degree of tumor VEGF and CD31 expression was statistically assessed using the chi(2) test verified with Yates' test for comparison of two groups. Significance was set at p < 0.05. RESULTS: Expression of VEGF was positive in 11 cases/16 of cases at diagnosis. Moreover, 8 cases/16 untreated osteosarcomas were CD31-negative, but the other 8 showed an high expression of CD31. VEGF expression in viable tumor cells after neoadjuvant chemotherapy was observed in all cases; in particular, there was an increased VEGF expression (post-chemotherapy VEGF--biopsy VEGF) in 11 cases/16. CD31 expression increased in 11 cases/16 and decreased in 3 cases after chemotherapy. The data relating to the change in staining following chemotherapy appear statistically significant for VEGF expression (p < 0.05), but not for CD31 (p > 0.05). CONCLUSIONS: Even if the study included few patients, these results confirm that VEGF and CD31 expression is affected by multidrug chemotherapy including HDMTX. The expression of angiogenic factors that increase microvessel density (MVD) can contribute to the penetration of chemotherapeutic drugs into the tumor in the adjuvant stage of treatment. So VEGF could have a paradoxical effect: it is associated with a poor outcome but it could be a potential target for anti-angiogenic therapy.