Tricalcium phosphate and hydroxyapatite treatment for benign cavitary bone lesions: A prospective clinical trial.

Benign bone tumors are surgically treated by curettage and by filling the defect using bone grafts or bone substitutes, such as hydroxyapatite crystals and tricalcium phosphate. The tricalcium phosphate mixed with hydroxyapatite, although fragile, is a good alternative with good integration. Fifteen patients with benign bone lesions were randomized in two groups surgically treated by curettage and filling of the bone defect using allograft (7 cases) or a mixture of 35% tricalcium phosphate, with 60-85% pore volume, and 65% hydroxyapatite (8 cases). After the surgery, all patients were followed up every 3 weeks until 6 months, and then at 2 months interval until one year for the clinical and radiological assessment. The average age was 35.4 years (from 18 to 54) for the allograft group and 41 years (from 22 to 58) for the patients treated with bone substitute. Eight patients were male and seven female, with relatively equal distribution between both groups. The average bone defect was relatively equal: 14 cc (4-25 cc) for the allograft group and 15.1 cc (4-33 cc) for the ceramic group (P>0.1). During the follow-up, all the lesions gradually disappeared after 12 months, with a time of healing of 18.8 weeks (15-24 weeks) for the allograft group and 20.37 weeks (15-28) for the bone substitute group. There were no significant differences regarding the clinical status and the radiological assessment after 12 months. No patient required extra pain medication after 2 weeks. No complications have been recorded. The surgical treatment of small and medium sized lytic benign tumors has good results with both types of graft that were studied. Using tricalcium phosphate mixed with hydroxyapatite as bone substitute represents a good and low cost alternative, but it is a relatively fragile material with a slower time to integrate compared to the allograft.

A new perspective towards failure of gamma nail systems.

Uncommon causes of nail failures and surgical reinterventions were determined. The study included 23 osteoporotic patients, 13 of whom followed a fast recovery program with early walking (FWB group). The other 10 patients were not allowed full weight bearing until 6 weeks (NFWB group). The T-score was determined before surgery for all cases. A case with a nail breakage after a failed DCS implant fixed in another clinic was also analyzed. The nail was revised and the broken implant underwent a metallurgic and microscopic examination. The average T-score was 2.5 for the patients that followed the fast recovery program and 2.7 for the patients from non-full weight bearing. Four patients, 1 from the NFWB group and 3 from FWB group, presented a screw cut-out. It was found that the errors of the guiding instruments may create dents, scratches or micro-fractures on the titanium coating that lead to an early implant failure. Imperfect reduction leads to incorrect implant placement and a high incidence of failure. Damaging the titanium protective coating, in a low force, high cycles scenario can cause structural failure. Delays in fracture healing and material fatigue are the most common causes of nail failure and can lead to catastrophic complications.

Radiographic Evaluation of Alignment Following Total Knee Arthroplasty - a Systematic Review. Part II.

The aim of this second part is to review the existing described methods for measuring postoperative total knee arthroplasty (TKA) alignment in sagital and axial plane as well as the existing literature regarding the axial plane evaluation with the use of computer tomography. Given that the most frequent mistakes when positioning the total knee arthroplasty components are made in the axial plane, it is necessary to know what are the limits of radiographic evaluation, for which CT scan is the most valuable tool in assessing the rotation of the components.

Radiographic Evaluation of Alignment Following TKA, a Systematic Review.

Postoperative assessment is of paramount importance in primary total knee arthroplasty. A thorough postoperative analysis helps the surgeon anticipate any postoperative potential issues and correlate the preoperative planning with the postoperative result, and provides better understanding of the importance of surgical principles of primary total knee arthroplasty. In addition, postoperative analysis helps the surgeon understand surgical errors and improve future outcomes. Standard radiographs, with a known magnification, should be obtained for postoperative total knee arthroplasty evaluation. Although imaging evaluation of knee arthroplasty is usually limited to conventional radiographs, examples of the utility of computed tomography are also illustrated, and suggested imaging strategies discussed.

Outcome of iatrogenic collateral ligaments injuries during total knee arthroplasty.

Soft tissue balance is an essential step in total knee arthroplasty by providing a good knee stability and an even distribution of load over the prosthesis components. During surgery, because of the need of having a good balance in most cases is necessary to do some soft tissue release in the medial compartment. Lateral release is far more rare and is generally needed for patients with valgus knees after high tibial osteotomy. Our purpose is to evaluate the complications that arise during soft tissue release and how to manage this unfortunate events for getting the best functional results for the patients. In this study, we analyzed 434 knee arthroplasties that were operated in our clinic in the past 8 years by the same knee team (2005-2012). Average age was 64.8 years. Eight of this patients had medial collateral ligament injuries during surgery, and two had lateral collateral ligament rupture. Average age of patients who suffered from medial collateral ligaments injuries was 62.8 years and for lateral collateral ligaments was 72.5 years. Body mass index was 34 for both groups. We used for evaluation the knee society pain and functional scores, and X-rays obtained after the surgery with a calibrated Siemens machine. Seven patients with MCL repair were satisfied with after surgery (Knee Society score was 87.7, and functional score was 80). One complained of knee instability associated with pain and needed revision. In LCL group, all patients had excellent results (Knee Society score was 91.5, and functional score was 85). We found that repair to collateral ligaments injuries must be obtained during surgery, especially complete ruptures of the MCL. There are several approaches to collateral ligaments ruptures during total knee arthroplasty that will be discussed during the article.

The effect of high tibial osteotomy on the posterior tibial slope.

INTRODUCTION: High tibial osteotomy remains a useful procedure for delaying total knee arthroplasty for young patients with unicompartimental medial osteoarthritis of the knee. The tibial posterior slope is essential for both ligament function and knee kinematics. Even though many articles were published in the literature, the long term influence of open wedge high tibial osteotomy on the posterior slope of the tibial plateau remains unknown. OBJECTIVE: We assessed the relationship among the degree of correction, the surgical technique, the postoperative modification of tibial slope, knee flexion and Knee score at the two years. MATERIAL AND METHODS: We used for evaluation a calibrated x-rays with correction factor. All the measures were done with Cedara I-View 6.3.2 application. All 47 patients were operated in our hospital between 2008-2011, with the same technique, open wedge high tibial osteotomy with an acrylic cement wedge. All patients postponed weight bearing for 6 weeks. RESULTS: We found that there is no statistical significance (p=0.2) between the preoperative varus and the after surgery tibial slope, but the resulting posterior inclination after surgery influences the tibial posterior slope at 2 years (p<=0.005).The degree of correction has a strong influence over the increase or decrease of tibial posterior slope(p<0.005). An increase in tibial slope increases the knee flexion by 1.45° for every degree of inclination (p<0.05). Functional results are not influenced by small modifications in tibial inclination (p>0.05). CONCLUSION: From this findings we may conclude that the most important factors that changes the posterior inclination of the tibia surface are the height of the cement wedge and the surgical technique, by placing the acrylic cement wedge more anteriorly. We have found that the vast majority of our high tibial osteotomies are in fact "flexion" osteotomies. At the 2 years control we have found a slight increase in tibial slope angle (average 1.77°) and knee flexion (average 2.56°) with no functional response. This is a case series study with level of evidence IV.