Intramedullary cement osteosynthesis (IMCO): a pilot study in sheep.

The application of bone substitutes and cements has a long standing history in augmenting fractures as a complement to routine fracture fixation techniques. Nevertheless, such use is almost always in conjunction with definite means of fracture fixation such as intramedullary pins or bone plates. The idea of using biomaterials as the primary fixation bears the possibility of simultaneous fixation and bone enhancement. Intramedullary recruitment of bone cements is suggested in this study to achieve this goal. However, as the method needs primary testings in animal models before human implementation, and since the degree of ambulation is not predictable in animals, this pilot study only evaluates the outcomes regarding the feasibility and safety of this method in the presence of primary bone fixators. A number of two sheep were used in this study. Tibial transverse osteotomies were performed in both animals followed by external skeletal fixation. The medullary canals, which have already been prepared by removing the marrow through proximal and distal drill holes, were then injected with calcium phosphate cement (CPC). The outcomes were evaluated postoperatively by standard survey radiographs, morphology, histology and biomechanical testings. Healing processes appeared uncomplicated until week four where one bone fracture recurred due to external fixator failure. The results showed 56% and 48% cortical thickening, compared to the opposite site, in the fracture site and proximal and distal diaphyses respectively. This bone augmentative effect resulted in 264% increase in bending strength of the fracture site and 148% increase of the same value in the adjacent areas of diaphyses. In conclusion, IMCO, using CPC in tibia of sheep, is safe and biocompatible with bone physiology and healing. It possibly can carry the osteopromotive effect of the CPCs to provide a sustained source of bone augmentation throughout the diaphysis. Although the results must be considered preliminary, this method has possible advantages over conventional methods of bone fixation at least in bones with compromised quality (i.e. osteoporosis and bone cysts), where rigid metal implants may jeopardize eggshell cortices.

Reconstruction for chronic grade-II posterior cruciate ligament deficiency in Malaysian military personnel.

PURPOSE: To evaluate the outcome of reconstruction for chronic grade-II posterior cruciate ligament (PCL) deficiency in Malaysian military personnel. METHODS: Medical records of 16 male military personnel aged 25 to 41 years who underwent reconstruction for chronic grade-II PCL deficiency using the quadruple hamstrings tendon by a single surgeon were reviewed. The mean time from injury to surgery was 43.6 (range, 3-104) months. 10 patients had grade-I (n=4), grade-III (n=2), and grade-IV (n=4) lesions of the medial femoral condyles. Seven patients had medial (n=6) and lateral (n=1) meniscus tears. At the 2-year follow-up, patients were asked to complete a questionnaire consisting of the Lysholm score, Tegner activity level, and International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form. Posterior drawer test, KT-2000 arthrometer test for posterior translation of the tibia, and military health grade (MHG) were assessed by an independent assessor. RESULTS: At the 2-year follow-up, the mean Lysholm score was 83; the score was excellent in 2 patients, good in 9, fair in 4, and poor in one. The mean IKDC subjective score was 74. The median Tegner activity level increased from 5.5 to 6. The posterior drawer test of 11 patients improved to grade I and the remaining 5 remained at grade II. The mean posterior translation of the tibia was 2.4 mm postoperatively; the posterior translation was normal in 8 patients, nearly normal in 7, and abnormal (≥ 6 mm) in one. The MHG improved in 14 patients and remained unchanged in 2. The latter 2 patients had no chondral lesion or meniscus injury. The first one was 40 years old with a postoperative IKDC score of 55 and a Tegner activity level of 2. The second one was 34 years old with a postoperative IKDC score of 65 and posterior translation of the tibia of 6 mm. CONCLUSION: Surgical reconstruction for chronic grade-II PCL injury achieved satisfactory outcome and may be appropriate for military personnel.