Kuo An Lai

Tourniquet use in total knee arthroplasty: a meta-analysis

PurposeThe use of an intraoperative tourniquet for total knee arthroplasty (TKA) is a common practice. However, the effectiveness and safety are still questionable. A systematic review was conducted to examine that whether using a tourniquet in TKA was effective without increasing the risk of complications.MethodsA comprehensive literature search was done in PubMed Medicine, Embase, and other internet database. The review work and the following meta-analysis were processed to evaluate the role of tourniquet in TKA.ResultsEight randomized controlled trials and three high-quality prospective studies involving 634 knees and comparing TKA with and without the use of a tourniquet were included in this analysis. The results demonstrated that using a tourniquet could decrease the measured blood loss but could not decrease the calculated blood loss, which indicated actual blood loss. Patients managed with a tourniquet might have higher risks of thromboembolic complications. Using the tourniquet with late release after wound closure could shorten the operation time; whereas early release did not show this benefit.ConclusionsThe current evidence suggested that using tourniquet in TKA may save time but may not reduce the blood loss. Due to the higher risks of thromboembolic complications, we should use a tourniquet in TKA with caution.

Correlating factors and clinical significance of flexible flatfoot in preschool children

To elucidate the correlating factors and clinical significance of flexible flatfoot (FF) in preschool children of Taiwan, a cross-sectional study was conducted in a research laboratory equipped with a gait analysis facility. Altogether, 377 preschool children (201 boys, 176 girls), ranging in age from 2 to 6 years, were enrolled in this investigation. The results show that age, height, weight, foot progression angle, occurrence of physical knock-knee, and joint laxity score correlate with FF. Children with FF, compared with children without, performed physical tasks poorly and walked slowly, as determined by gait parameters. The FF should not simply be regarded as a problem of static alignment of the ankle and foot complex, but may be the consequence of a dynamic functional change of the lower extremity. Better understanding of the correlating factors and the clinical relevance of FF may prove helpful in deciding on the most appropriate treatment for a particular patient.

Failure of hydroxyapatite-coated acetabular cups

Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening. The retrieved acetabular cups were studied by SEM and image-processing techniques to quantify the amount of residual HA on the cup. This was correlated with the clinical variables and modes of failure. The residual HA (as a percentage of the surface) on the loose cups correlated negatively with the duration of implantation (r = -0.732, p < 0.001). Six cups were stable at revision and had more residual HA coating than those which were loose (p < 0.01). The rate of failure of the Landos Atoll HA-coated, smooth hemispherical cup with screw fixation is unacceptably high. Resorption of the HA coating is markedly increased in loose cups compared with stable cups. HA coating cannot substitute for stable mechanical fixation.

Effects of tourniquet use on blood loss and soft-tissue damage in total knee arthroplasty: a randomized controlled trial.

BACKGROUND Although tourniquets are widely used in total knee arthroplasty, their effectiveness in reducing blood loss and their influence on the postoperative course remain unclear. Tourniquet-related soft-tissue damage is a related concern. We performed a prospective, randomized, controlled trial to clarify the effect of tourniquets in total knee arthroplasty. METHODS Seventy-two patients undergoing total knee arthroplasty were randomly allocated to a tourniquet or non-tourniquet group. Blood loss and changes in C-reactive protein, creatine phosphokinase, and other indicators of soft-tissue damage were monitored preoperatively and postoperatively on Days 1, 2, and 4. Thigh pain, knee pain, limb swelling, rehabilitation progress, and hospital stays were also recorded for comparison. RESULTS Patients in the tourniquet group showed smaller decreases in hemoglobin (mean and standard deviation, 2.6 ± 0.9 versus 3.7 ± 1.3 g/dL) and hematocrit (7.6% ± 2.8% versus 10.4% ± 4.0%), less calculated blood loss (303 ± 119 versus 423 ± 197 mL), and smaller increases in C-reactive protein (peak value, 175 ± 55 versus 139 ± 75 mg/dL) and creatine phosphokinase (peak value, 214 ± 89 versus 162 ± 104 U/L) compared with those in the non-tourniquet group. There was slightly less postoperative pain in the non-tourniquet group. There were no significant differences between the groups in terms of swelling, rehabilitation progress, or hospital stays. CONCLUSIONS The use of a tourniquet during total knee arthroplasty was effective for reducing blood loss and avoiding excessive postoperative inflammation and muscle damage. The use of a tourniquet was related to slightly more postoperative pain but did not affect postoperative recovery.

Two-stage cementless revision THR after infection. 5 recurrences in 40 cases followed 2.5-7 years

We revised 40 infected hip prostheses in 40 patients as a two-stage procedure, including intravenous and oral antibiotics, gentamicin beads, and delayed cementless implantation of porous-coated THR. The duration of antibiotic treatment was 8 weeks. The interval from resection to reimplantation was, on average, 48 (8-108) weeks. 39 patients were followed, on average, 4 (2.5-7) years. 5 patients had a recurrent infection. In patients who did not have a recurrent infection, the Harris hip score exceeded 80 in 32 patients. Radiographically, femoral component migration of 2-6 mm was noted in 3 cases. The recurrent infection rate, and the functional and radiographic results are comparable with those obtained using a two-stage procedure with antibiotic cement.

Alendronate in the prevention of collapse of the femoral head in nontraumatic osteonecrosis: a two-year multicenter, prospective, randomized, double-blind, placebo-controlled study.

OBJECTIVE Osteonecrosis is one of the major debilitating skeletal disorders. Most patients with osteonecrosis of the femoral head eventually need surgery, usually total hip arthroplasty (THA), within a few years of onset. Previous studies showed that alendronate has a pharmacologic effect in reducing osteoclast activity and that it significantly reduced the incidence of collapse of the femoral head in the osteonecrotic hip. The purpose of this study was to determine the cumulative incidence of THA in patients with osteonecrosis of the femoral head and the time-to-event after treatment with alendronate versus placebo during the study period. METHODS A 2-year multicenter, prospective, randomized, double-blind study was performed. From June 2005 to December 2006, 64 patients were enrolled and randomly assigned to the alendronate or placebo group. In patients with bilateral hip osteonecrosis who met the inclusion criteria, both hips were counted in the analyses. Five patients were excluded from the analysis because they did not comply with any of the study regimens. Seven patients were ineligible because they were not diagnosed as having stage IIC or stage IIIC disease according to the University of Pennsylvania system. Thus, a total of 52 patients (65 hips) were assessed in this study. Disease progression was evaluated by radiography and magnetic resonance imaging (MRI). The Harris Hip Score and the Short Form 36 health survey were used to rate hip function and quality of life, respectively. RESULTS There was no significant difference in radiographic and MRI data between the 2 study groups. Four of 32 hips in the alendronate treatment group underwent THA, while 5 of 33 hips in the placebo group had THA (P = 0.837). No differences were noted in disease progression, Harris Hip Scores, or Short Form 36 scores between the 2 groups. CONCLUSION Alendronate has no obvious effect on preventing the necessity for THA, reducing disease progression, or improving life quality.

A nationwide seven-year trend of hip fractures in the elderly population of Taiwan

To investigate the recent longitudinal trend of hip fractures (including cervical and trochanteric fractures) in Taiwans elderly population (> or =65 years), a nationwide descriptive epidemiological study was conducted using the database of the Bureau of National Health Insurance from 1996 through 2002. Frequencies and incidences of hip fracture by gender, fracture site, and age group were estimated, and the 7-year incidence trend was further evaluated. The results showed that a total of 75,482 hip fractures occurred during the study period with an incidence rate of 57.54 per 10,000 per year. Overall incidence significantly increased by 30% (p<0.0001), from 49.56 to 64.37 per 10,000 per year during the 7-year study period. The increase in rates was greater in males (36%) than in females (22%). The average female-to-male ratio was 1.76, lower than those in many countries. In females, the annual incidence of cervical fracture was higher than that of trochanteric fractures throughout the 7 years, while the incidence of trochanteric fractures was higher than cervical fractures each year in males (p<0.0001). The average annual incidence of patients older than 85 years was 9.9 times higher than that of aged 65 to 69 years in females and 7.9 times in males. Development and implementation of public health strategies for hip fractures should more focus on these subgroups in Taiwans rapidly aging society.

Arthrodesis with a short Huckstep nail as a salvage procedure for failed total knee arthroplasty.

Arthrodesis of the knee with use of a short Huckstep nail was performed in thirty-three patients (thirty-three knees) after failure of a non-constrained total knee arthroplasty. The indication for the arthrodesis was an infection in thirty-one knees and a Charcot joint in two. Three knees had had a failed attempt at arthrodesis with use of external fixation. The Huckstep nail was inserted through the knee, retrograde into the femur, and then antegrade into the tibia. The duration of the operation averaged 104 minutes (range, sixty-five to 155 minutes). Local bone graft was used in all knees. At the time of follow-up, at an average of forty-seven months (range, eighteen to ninety-four months), thirty knees (91 per cent) had radiographic evidence of union. The average time to union was 5.2 months (range, two to ten months) after the arthrodesis. Eight knees that had a grossly purulent infection were treated with débridement, which was followed by the arthrodesis as a second-stage procedure; the other knees had a one-stage arthrodesis. Only one of the thirty-one knees that had had an infection before the arthrodesis had a recurrence after it. Arthrodesis with a short Huckstep nail provides immediate axial and rotational stability and allows weight-bearing without use of external support as well as placement of the knee in a slightly flexed and valgus position. In addition, the nail does not migrate and it may be used even when there is a standard-size prosthesis in the ipsilateral hip.

Temporary drainage clamping after total knee arthroplasty: a meta-analysis of randomized controlled trials.

Drainage-clamping methods are thought to be effective in reducing blood loss after total knee arthroplasty (TKA). We conducted a systematic review to examine if these methods were effective without increasing the risk of complications. After a comprehensive search, 6 randomized controlled trials involving 603 knees and comparing clamping drainage and the immediate release of the drain after elective TKA were included in this analysis. The results demonstrated that drainage clamping could decrease the volume of drainage, but only clamping for no less than 4 hours could reduce the true blood loss. There was no significant difference between the 2 groups regarding blood transfusion, postoperative range of motion, incidence of thromboembolic events, and wound complications. The current evidence cannot confirm the advantage of clamping drainage after TKA.

The relation between micromotion and screw fixation in acetabular cup

One of the major causes inducing loosening in the cementless acetabular cup implanting is its insufficient initial stability. In this study, three-dimensional finite element models of the pelvis and acetabular components were developed to investigate the relationship between relative micromotion, initial stability, and screw fixation under six daily activity loadings. A commercial available hemispheric cup with five screw holes was used as the target acetabular cup. The simulation results showed that if screws were placed closed together, when the screw number increased from 1 to 5, the peak micromotion decreased less than 14%, from 126.5 to 108.8 microm, while the stable region, micromotion less than 28 microm, enlarged only by 40%, from 46.1% to 64.7%. However, if the screw could be placed near the cup rim, a single rim screw, 202.1 microm micromotion, could provide better stability than that of four dome screws, 209.6 microm micromotion, placed closed together. To conclude, multiple cup screws should be placed near cup rim and as separate as possible to enlarge the stable region and reduce the peak micromotion between cup and acetabulum.