Sex comparison of familial predisposition to anterior cruciate ligament injury.

PURPOSE: In an effort to identify risk factors for anterior cruciate ligament (ACL) injury, many potential risk factors have been proposed, including familial predisposition. However, no study has evaluated familial predisposition in male or females separately. The purpose of this study was to determine whether a familial predisposition to ACL injury exists in both males and females. METHODS: One hundred and twenty (78 males and 42 females) patients who had undergone surgical ACL reconstruction were recruited as the ACL group, and 107 patients (67 males and 40 females) that had undergone arthroscopic partial menisectomy, with no previous history of ACL injury, were recruited as the referent control group. A familial ACL injury and subject particulars questionnaire was completed. RESULTS: When all subjects were combined, the ACL group (20.0 %, 24 of 120) did not demonstrate a higher familial (first-degree relative) prevalence (n.s.) of ACL injury compared to the referent control group (15.0 %; 16 of 107 patients). When the data were stratified by sex, the male ACL group (19.2 %, 15 of 78) demonstrated a significantly higher familial (first-degree relative) prevalence (P = 0.02) of ACL injury compared to the male referent control group (7.5 %; 5 of 67 patients). There were no differences among the females (n.s.). DISCUSSION: The results of this study show that male patients with ACL tears are more likely to have a first-degree relative with an ACL tear compared to male referent control subjects. Future research is warranted to better delineate sex-specific risk factors for ACL injuries could help guide intervention programs aimed at preventative treatment strategies, especially in high-risk families.

Cement augmentation of pedicle screw fixation using novel cannulated cement insertion device.

STUDY DESIGN: A biomechanical study with human cadaveric osteopenic lumbar vertebrae evaluating a novel method for cement augmentation of pedicle screw fixation. OBJECTIVES: To examine (1) the resistance to toggling and (2) ease of screw removal following cement augmentation of pedicle screw fixation via a novel, cannulated cement delivery device, allowing placement of a standard pedicle screw into a cement-augmented tract. SUMMARY OF BACKGROUND DATA: Some recent studies have investigated various cannulated pedicle screws through which polymethylmethacrylate (PMMA) is injected and found improved fixation in osteopenic spines. However, when necessary because of revision surgery, extraction of screws cemented via a cannulated system is exceedingly difficult. METHODS: Novel cannulated screws were fabricated with fenestrations in the distal one-third of the screws. Fresh osteopenic (by dual energy x-ray absorptiometry) cadaveric lumbar vertebrae were instrumented with an uncemented pedicle screw in 1 pedicle and the novel cemented screw in the opposite pedicle. Vertebral augmentation was performed by placement of the novel screw and injection of 2.5 mL of PMMA. Before final cement hardening, the novel screw was removed and replaced with a standard pedicle screw. The pedicle screws in 13 vertebral bodies were subjected to 10,000 cycles of cephalocaudal toggling. In another 10 vertebral bodies, we measured the torque required to remove uncemented, cemented screws, and cemented fenestrated screws left in place until hardening. RESULTS: There was 63% less cephalocaudal motion with cemented screws using the new technique versus uncemented screws. Torque required for screw removal was similar for uncemented screws (mean, 358 Nmm) and PMMA-augmented screws via this new technique (mean, 343 Nmm). However, fenestrated screws cemented into place required an average of 4100 Nmm. CONCLUSION: This novel cement-delivery screw and injection technique provides a significant increase in resistance to pedicle screw motion, allowing placement of a standard screw that can be removed in revision surgery.

Osteocutaneous radial forearm free flap: long-term radiographic evaluation of donor site morbidity after prophylactic plating of radius.

The osteocutaneous radial forearm free flap (ORFFF) is an ideal source of vascularized bone and soft tissue for repair of defects in reconstructions of the head and neck. However, studies have revealed significant donor site morbidity, decreasing the popularity of this procedure. We have previously reported our technique of prophylactic internal fixation of the radius at the time of graft harvest, developed to decrease donor radius fractures. This is a retrospective radiographic review of our long-term radius donor site morbidity. Forearm radiographs more than 3 years after ORFFF with prophylactic plating were evaluated and compared with prior postoperative films. No donor radius fractures were identified. All radiographs exhibited remodeling and/or reconstitution of donor radii. There was no evidence of implant failure, loosening, or surrounding osteopenia. This study lends further credibility to the ORFFF, when prophylactically plated, as a safe and reliable source of vascularized bone and soft tissue for reconstructive procedures.

Immunohistochemical localization of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 during induced heterotopic bone formation.

The distribution and staining intensity of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 were assessed by immunohistochemistry in ectopic bone induced in Nu/Nu mice by Saos-2 cell derived implants. Devitalized Saos-2 cells or their extracts can induce endochondral bone formation when implanted subcutaneously into Nu/Nu mice. BMP staining was mostly cytoplasmic. The most intense BMP staining was seen in hypertrophic and apoptotic chondrocytes, osteoprogenitor cells such as periosteal and perivascular cells, and osteoblasts. BMP staining in osteocytes and osteoclasts was variable, ranging from undetectable to intensely stained, and from minimal to moderately stained in megakaryocytes of the induced bone marrow. BMP-2, 4, 6, and 7 staining in Saos-2 implant-induced bone indicates the following: (1) Saos-2 cell products promote expression of BMPs by host osteoprogenitor cells, which in turn, leads to bone and marrow formation at ectopic sites; (2) strong BMP staining is seen in maturing chondrocytes, and thus may play a role in chondrocyte differentiation and/or apoptosis; (3) BMP expression in perivascular and periosteal cells indicates that osteoprogenitor cells also express BMP; (4) BMP release by osteoclasts may promote osteoblastic differentiation at sites of bone remodeling. These new data can be useful in understanding the role of BMPs in promoting clinical bone repair and in various pathologic conditions.

Localization of bone morphogenetic proteins (BMPs)-2, -4, and -6 within megakaryocytes and platelets.

In this study, we localized bone morphogenetic proteins (BMPs), proteins known to induce ectopic osteogenesis, within megakaryocytes and in lysates of human platelets. Immunohistochemistry localized BMP-2, -4, and -6 within marrow megakaryocytes of 5-week-old rat tibias. In situ hybridization was utilized to confirm the presence of BMP-2, BMP-4, and BMP-6 mRNA in 2- to 3-week-old mouse tibial marrow megakaryocytes. Finally, the presence of BMP-2, -4, and -6 was confirmed in human platelet lysates using Western blot technique. The expression and release of BMPs by megakaryocytes, within platelets and perhaps by secretion, may help to explain recent reports of excessive bone formation associated with increased numbers of marrow megakaryocytes in GATA-1- or NF-E2 gene-deficient mice. Also, excess local release of BMPs may provide an explanation for the bone overgrowth (osteosclerosis) seen in human patients suffering from a type of myelogenous leukemia characterized by increased numbers of marrow megakaryocytes.