Displaying all 8 publications

Abstract:
Sort:
  1. Yang Harmony TC, Yusof N, Ramalingam S, Baharin R, Syahrom A, Mansor A
    Clin Orthop Relat Res, 2022 Feb 01;480(2):407-418.
    PMID: 34491235 DOI: 10.1097/CORR.0000000000001968
    BACKGROUND: Gamma irradiation, which minimizes the risk of infectious disease transmission when human bone allograft is used, has been found to negatively affect its biomechanical properties. However, in those studies, the deep-freezing temperature during irradiation was not necessarily maintained during transportation and sterilization, which may have affected the findings. Prior reports have also suggested that controlled deep freezing may mitigate the detrimental effects of irradiation on the mechanical properties of bone allograft.

    QUESTION/PURPOSE: Does a controlled deep-freezing temperature during irradiation help preserve the compressive mechanical properties of human femoral cortical bone allografts?

    METHODS: Cortical bone cube samples, each measuring 64 mm3, were cut from the mid-diaphyseal midshaft of five fresh-frozen cadaver femurs (four male donors, mean [range] age at procurement 42 years [42 to 43]) and were allocated via block randomization into one of three experimental groups (with equal numbers of samples from each donor allocated into each group). Each experimental group consisted of 20 bone cube samples. Samples irradiated in dry ice were subjected to irradiation doses ranging from 26.7 kGy to 27.1 kGy (mean 26.9 kGy) at a deep-freezing temperature below -40°C (the recommended long-term storage temperature for allografts). Samples irradiated in gel ice underwent irradiation doses ranging from 26.2 kGy and 26.4 kGy (mean 26.3 kGy) in a freezing temperature range between -40°C and 0°C. Acting as controls, samples in a third group were not subjected to gamma irradiation. The mechanical properties (0.2% offset yield stress, ultimate compression stress, toughness, and the Young modulus) of samples from each group were subsequently evaluated via axial compression loading to failure along the long axis of the bone. The investigators were blinded to sample group during compression testing.

    RESULTS: The mean ultimate compression stress (84 ± 27 MPa versus 119 ± 31 MPa, mean difference 35 [95% CI 9 to 60]; p = 0.005) and toughness (3622 ± 1720 kJ/m3 versus 5854 ± 2900 kJ/m3, mean difference 2232 [95% CI 70 to 4394]; p = 0.009) of samples irradiated at a higher temperature range (-40°C to 0°C) were lower than in those irradiated at deep-freezing temperatures (below -40°C). The mean 0.2% offset yield stress (73 ± 28 MPa versus 109 ± 38 MPa, mean difference 36 [95% CI 11 to 60]; p = 0.002) and ultimate compression stress (84 ± 27 MPa versus 128 ± 40 MPa, mean difference 44 [95% CI 17 to 69]; p < 0.001) of samples irradiated at a higher temperature range (-40°C to 0°C) were lower than the nonirradiated control group samples. The mean 0.2% offset yield stress (73 ± 28 MPa versus 101 ± 28 MPa, mean difference 28 [95% CI 3 to 52]; p = 0.02; effect size = 1.0 [95% CI 0.8 to 1.2]) of samples irradiated at higher temperature range (-40°C to 0°C) were no different with the numbers available to those irradiated at deep-freezing temperature. The mean toughness (3622 ± 1720 kJ/m3 versus 6231 ± 3410 kJ/m3, mean difference 2609 [95% CI 447 to 4771]; p = 0.02; effect size = 1.0 [95% CI 0.8 to 1.2]) of samples irradiated at higher temperature range (-40°C to 0°C) were no different with the numbers available to the non-irradiated control group samples. The mean 0.2% offset yield stress, ultimate compression stress, and toughness of samples irradiated in deep-freezing temperatures (below -40°C) were not different with the numbers available to the non-irradiated control group samples. The Young modulus was not different with the numbers available among the three groups.

    CONCLUSION: In this study, maintenance of a deep-freezing temperature below -40°C, using dry ice as a cooling agent, consistently mitigated the adverse effects of irradiation on the monotonic-compression mechanical properties of human cortical bone tissue. Preserving the mechanical properties of a cortical allograft, when irradiated in a deep-freezing temperature, may have resulted from attenuation of the deleterious, indirect effects of gamma radiation on its collagen architecture in a frozen state. Immobilization of water molecules in this state prevents radiolysis and the subsequent generation of free radicals. This hypothesis was supported by an apparent loss of the protective effect when a range of higher freezing temperatures was used during irradiation.

    CLINICAL RELEVANCE: Deep-freezing temperatures below -40°C during gamma irradiation may be a promising approach to better retain the native mechanical properties of cortical bone allografts. A further study of the effect of deep-freezing during gamma radiation sterilization on sterility and other important biomechanical properties of cortical bone (such as, tensile strength, fracture toughness, and fatigue) is needed to confirm these findings.

  2. Siow WM, Chin PL, Chia SL, Lo NN, Yeo SJ
    Clin Orthop Relat Res, 2013 May;471(5):1451-7.
    PMID: 23299954 DOI: 10.1007/s11999-012-2776-7
    There is marked racial disparity in TKA use rates, demographics, and outcomes between white and Afro-Caribbean Americans. Comparative studies of ethnicity in patients undergoing TKAs have been mostly in American populations with an underrepresentation of Asian groups. It is unclear whether these disparities exist in Chinese, Malays, and Indians.
  3. Lee CK, Chua YP, Saw A
    Clin Orthop Relat Res, 2012 Feb;470(2):610-5.
    PMID: 21842299 DOI: 10.1007/s11999-011-1990-z
    Pin site infection is a common problem in external fixation. Plain gauze wetted with normal saline is commonly used for a pin site dressing owing to the simplicity and low cost. Evidence to support adding an antimicrobial agent in the dressing material is lacking.
  4. Devnani AS
    PMID: 15685053
    In children with delayed presentation of displaced supracondylar fractures, closed or open reduction with K-wire fixation risks complications. Gradually reducing the fracture with traction potentially reduces these risks. An unacceptable deformity can be corrected later by an osteotomy. This concept was used for 28 children, with an average age of 7 years 6 months, who presented after an average delay of 5.6 days. Their stay in the hospital was 14 days on average. At followup (average, 24 months), five children (18%) who had cubitus varus greater than 10 degrees had corrective osteotomy. There were no additional neurovascular injuries after treatment. The results are comparable with other methods of treatment.
  5. Yeap JS, Singh D, Birch R
    PMID: 11210956
    A system for assessing the results of tibialis posterior tendon transfers in the treatment of foot drop secondary to nerve palsy is proposed. There are seven sections to this scoring system: pain, need for orthosis, ability to wear normal shoes, activity level, muscle power of ankle dorsiflexion, degree of active ankle dorsiflexion, and foot posture. The total score is 100. The results are classified as excellent for scores between 85 and 100, good between 70 and 84, fair between 55 and 69, and poor for scores below 55. The results of 18 patients (mean followup, 64.6 months) who had a tibialis posterior tendon transfer were assessed using this method. Four patients (22.2%) had an excellent result, seven (38.8%) had a good result, two (11.1%) had a fair result, and five (27.7%) had a poor result. The average score was 67.2, suggesting an overall fair result for this operation. In nine patients, there was correlation between the outcome when assessed with this method and with patient rating. In two patients, the outcomes were better when assessed with this method than with patient rating, whereas the reverse was true in seven other patients. Thus, this system may provide a more objective and critical evaluation of tibialis posterior transfers for foot drop.
  6. Sengupta S
    Clin Orthop Relat Res, 1985 Jan-Feb;?(192):193-8.
    PMID: 3967422
    Yaws, a spirochetal infection that is endemic in certain tropical countries, including Malaysia, may present with various orthopedic problems. As the condition is relatively unknown, diagnosis is often missed, which leads to poor management. There are initial, early, and late phases of the disease process. By involving skin, bone, and joints, yaws can produce deep ulcerations, joint deformities, and bone destruction. Within a ten-year period in Malaysia, 14 cases of serologically proven yaws have been treated for chronic ulcers, gross joint deformities, and pathologic fractures.
  7. Silva JF, Subramanian N
    Clin Orthop Relat Res, 1975 Nov-Dec;?(113):119-27.
    PMID: 1059509
    To explore the possibility that environmental and/or genetic factors may yield clues to the etiology of osteogenic sarcoma, an epidemiologic retrospective study of all cases of osteogenic sarcoma in a country with clear geographic and racial variables (Malaysia) was conducted covering a 4-year period. Sixty-eight cases were identified (+85% of the predicted total). The incidence (cases per 100,000 population per year) was 0.11 in Malay, 0.23 in the Chinese, and 0.23 in the Indian. The urban versus rural incidence in the Malay was 0.22 versus 0.09, and in the Chinese 0.31 versus 0.18. The Indian population was too small when dividied into urban and rural segments to be significant.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links