The efficacy of subcutaneous local analgesic infusion in the early postoperative period after bilateral total knee arthroplasty.

OBJECTIVES: This study aims to evaluate the analgesic and functional efficacy of subcutaneous local analgesic infusion (ScLAI) in the early postoperative period (especially on the second postoperative day) in patients undergoing simultaneous bilateral total knee arthroplasty with an intraoperative periarticular injection (PAI) of local analgesic cocktail. PATIENTS AND METHODS: Fifteen patients (1 male, 14 females; mean age 62 years; range 52 to 76 years) who underwent simultaneous bilateral total knee arthroplasty (30 knees) and who received the same pre- and intraoperative analgesic protocols were included in this randomized, double-blind, placebo-controlled study. By using a flexible catheter, bupivacaine was administered for ScLAI to either knee (ScLAI group) and placebo infusion was applied to the other one (control group). Postoperative visual analog scale (VAS) pain scores and knee functions were compared between bupivacain and placebo infused knees. RESULTS: In the ScLAI group, VAS pain scores were lower than the control group during knee flexion and straight leg raise activities (SLR) on the second postoperative day. ScLAI also prevented the rebound pain following intraoperative PAI of local analgesic cocktail and prolonged the analgesic efficacy period of the cocktail during both knee flexion and SLR. CONCLUSION: Subcutaneous infusion of bupivacaine in patients undergoing simultaneous bilateral total knee arthroplasty may prevent emergence of the rebound pain arising after application of intraoperative PAI of local analgesic cocktail and prolong the analgesic efficacy of the cocktail during both knee flexion and SLR activities on the second postoperative day.

Diagnostic efficacy of standard knee magnetic resonance imaging and radiography in evaluating integrity of anterior cruciate ligament before unicompartmental knee arthroplasty.

OBJECTIVE: The purpose of this study was to investigate the diagnostic efficacy of standard magnetic resonance imaging (MRI) and plain radiographs in determining the status of anterior cruciate ligament (ACL) for surgical decision-making processes in cases of medial unicompartmental knee arthroplasty (UKA). METHODS: A total of 59 knees of 36 consecutive patients who underwent knee replacement surgery were analyzed retrospectively. MRI scans were assessed independently by 3 observers (radiologists), while the plain radiographs were evaluated by an independent radiologist. Results were compared with the intraoperative ACL status. Cross tabulation was used for descriptive statistics to analyze sensitivity, specificity, and accuracy of MRI and plain radiographs. RESULTS: When the same observer assessed and classified the MRI twice, the reproducibility of the classification system varied from moderate to excellent. However, the interobserver concordance was moderate. The sensitivity of MRI was 73% and the specificity was 81%, while the sensitivity and specificity of plain radiographs was 36% and 79%, respectively. The accuracy of MRI was 80%, while that of the radiographs was 71%. CONCLUSION: Detection of intact ACL may be possible on available plain radiographs without necessity for additional means such as MRI, which may cause increase costs and loss of time. In cases where there is uncertainty regarding ACL integrity in degenerative knees, although standard MRI provides additional information on ACL status, it is not of sufficient diagnostic value.

Biomechanical evaluation of syndesmotic screw design via finite element analysis and Taguchi's method.

BACKGROUND: Screw fixation of syndesmotic injuries facilitates ligament healing and restoration of ankle stability, but failure of the screw might threaten the success of the treatment. Screw design parameters, such as outer diameter, inner diameter, thread pitch, leading edge radius, trailing edge radius, leading edge angle, and trailing edge angle, might have effects on the stresses that occur in the screws. This is the first study, to our knowledge, to investigate which geometric screw parameters play key roles in stresses that occur in screws used for syndesmotic fixation. METHODS: A three-dimensional finite element model of an ankle was reconstructed. Four different types of titanium screws­4.5-mm malleolar, 4-mm cancellous, 4-mm machine, and 3.5-mm cortical­were placed on this model. Physiologic load was applied to evaluate the stress in the screw. Then the contribution of each design factor to stress in the screws was analyzed systematically by Taguchi's robust design method. RESULTS: The maximum equivalent ductile failure (von Mises equivalent stress) value was found in the 4-mm cancellous screw (402 MPa). Taguchi's analysis showed that the descending order of contribution of the design factors to stress emerging on the screw is inner diameter, leading edge angle, thread pitch, outer diameter, and trailing edge angle. CONCLUSIONS: Stress that occurs in syndesmotic screws is closely related to their geometry and dimensions. According to the results, a 3.5-mm cortical screw with the ideal screw design regarding optimal parameters to resist against stresses in the syndesmosis seems more reasonable to choose in syndesmotic fixation.

Suture anchor fixation strength with or without augmentation in osteopenic and severely osteoporotic bones in rotator cuff repair: a biomechanical study on polyurethane foam model.

BACKGROUND: The purpose of the present study was to compare the results of various types of anchor applications with or without augmentation in both osteopenic and severely osteoporotic bone models. METHODS: Two different types of suture anchors were tested in severely osteoporotic (SOP) and osteopenic polyurethane (PU) foam blocks using an established protocol. An Instron machine applied static loading parallel to the axis of insertion until failure, and the mean anchor failure strengths were calculated. The mode of failure (anchor pullout, suture tear) was recorded. The anchors tested included the Corkscrew (CS) (Arthrex Inc., Naples, FL, USA) (without augmentation, polymethylmethacrylate (PMMA)-augmented, and bioabsorbable tricalcium phosphate (TCP) cement-augmented) and Corkscrew FT II (CS FT II) 5.5 mm (without augmentation as used routinely). RESULTS: The mean failure loads for both SOP and osteopenic PU foam blocks, respectively, were as follows: CS, 16.2 and 212.4 N; CS with TCP, 75.2 and 396 N; CS with PMMA, 101.2 and 528.8 N; CS FT II, 13.8 and 339.8 N. CONCLUSIONS: Augmentation of CS with TCP or PMMA would be essential to SOP bones. In the osteopenic bone model, although anchor fixation augmented with PMMA is the best fixation method, CS augmented with TCP cement or CS FT II without any need for augmentation may also be used as an alternative.

An assessment of sleep quality in patients undergoing total knee arthroplasty before and after surgery.

OBJECTIVE: The aim of this study was to compare the sleep quality of patients who underwent total knee arthroplasty before and after the surgery and analyze the effect of total knee arthroplasty on sleep quality. METHODS: The study included 42 patients (32 females, 10 males) who underwent total knee arthroplasty for primary knee osteoarthritis. For each patient the preoperative 1 day and postoperative 3 months results of Pittsburgh Sleep Quality Index (PSQI) and 100-mm visual analogue scale (VAS) were compared. RESULTS: The preoperative mean PSQI was 9. VAS score decreased in 97.6% of the patients, while sleep quality increased in 78.6%. 85.7% of the patients reported to have less episodes of pain related sleep disturbances. While both the PSQI and VAS improved after the surgery, there was no correlation between the parameters (p>0.05). CONCLUSION: Our results suggested that total knee arthroplasty surgery relieves pain and improves sleep quality. The improvement in sleep quality does not appear to be related to pain relief.

Biomechanical evaluation of syndesmotic screw position: a finite-element analysis.

OBJECTIVES: To evaluate the stresses in syndesmotic screws and widening of syndesmosis under loading after placement of the screws at different levels from the ankle joint line and to determine the optimal level. METHODS: From a set of computed tomographic data of an ankle, a 3-dimensional finite-element model was reconstructed. Six fixation configurations of the syndesmosis with placement of 3.5 or 4.5 mm single tricortical screws at 20-45 mm from the tibiotalar joint were performed on this model. Physiological loads approximating those during both midstance and heel-off states of stance phase of normal walking were applied to evaluate the stress in the screw and widening of the syndesmosis. RESULTS: Among the 6 fixation configurations, the lowest von Mises stress was found in the screws placed 30-40 mm above the joint line (373.31-380.17 MPa for 3.5 mm cortical screw and 284.06-327.31 MPa for 4.5 mm cortical screw in midstance phases), whereas the least syndesmosis widening was determined when the screw was placed 30 mm above the tibial plafond (0.005 mm) for 3.5 mm cortical screw and 20, 25, and 30 mm above the tibial plafond (0.004 mm for each, respectively) for 4.5 mm cortical screw during midstance phases. CONCLUSIONS: This study showed that syndesmosis fixation at the level of 30-40 mm above the tibiotalar joint has advantages with regard to stress in screws in comparison with the other evaluated levels.

Three-dimensional finite element analysis used to compare six different methods of syndesmosis fixation with 3.5- or 4.5-mm titanium screws: a biomechanical study.

BACKGROUND: Use of thicker and longer (four cortices) screws or of multiple screws seems to be more stable and efficient for syndesmosis fixation. METHODS: A three-dimensional finite element model of an ankle was constructed from serial axial sections from an existing two-dimensional computed tomographic image. Constructions of syndesmosis fixation with 3.5-mm single tricortical, 3.5-mm single quadricortical, 3.5-mm double tricortical, 3.5-mm double quadricortical, 4.5-mm single tricortical, and 4.5-mm single quadricortical screws were performed on this model. Physiologic loads approximating those during stance phase normal walking were applied to this ankle system. Stress values on the screws using the six fixation methods were compared. RESULTS: The highest maximum stress was determined over 3.5-mm cortical screws applied as single quadricortical, and the lowest maximum stress was determined over the 4.5-mm cortical screw applied as single quadricortical. Stress on the 3.5-mm single screw with quadricortical application was found to be higher than that with tricortical application and also compared with the 4.5-mm quadricortical screw application. Differences between the 4.5-mm single tricortical and quadricortical screws and between the 3.5-mm single tricortical and 3.5-mm double tricortical screw applications were not significant. CONCLUSIONS: Quadricortical application of 3.5-mm single screws and tricortical application of 3.5-mm double cortical screws are not good choices for syndesmosis fixation. If the plan is tricortical application, a 3.5-mm single cortical screw is adequate. If quadricortical application of syndesmosis fixation is planned, a 4.5-mm cortical screw should be used.

Pin site care during circular external fixation using two different protocols.

OBJECTIVES: Treatment of tibial fractures with Ilizarov external fixation is a valuable treatment alternative; however, development of problems at the pin site is one of the major drawbacks of this technique. Moreover, there is no general agreement regarding pin site care. The purpose of this study was to compare the efficacy of two different pin site care techniques after treatment of tibial fractures with an Ilizarov external fixator. DESIGN: Prospective randomized study. SETTING: Department of Orthopaedic Surgery of education and research hospital. PATIENTS AND METHODS: In this prospective randomized study, we followed up 610 pin sites in 39 cases using two different pin site care protocols. INTERVENTION: For the first 15 days, patients in both groups cleaned each pin site using sterile gauze impregnated with 10% polyvinylpyrrolidone iodine (Polyod) every 3 days. After 15 days, patients in group 1 (20 cases, 310 pin sites) were advised to perform pin care by daily showering and brushing the pin sites with soap and an ordinary soft toothbrush, whereas patients in group 2 (19 cases, 300 pin sites) were advised to perform pin care by daily showering and cleaning the crusts using sterile gauze impregnated with 10% polyvinylpyrrolidone iodine (Polyod). Each pin site was denominated according to location. MAIN OUTCOME MEASUREMENTS: Pin sites were inspected and graded on a scale of 0 to 5 according to slight modification of the system of Dahl described by Gordon et al during outpatient visits on the 5th, 10th, 15th, 30th, 45th, 60th, 75th, 90th, 120th, and 150th days of follow up after the operation until fixator removal. Grade 1 and grade 2 infections were categorized as minor infection not requiring any extra pin site care and grade 3 and above infections as major infection. RESULTS: Minor infection rate of all pin sites was determined as 50.7% in group 1 and 43.6% in group 2. Major infection rate was determined as 3.5% in group 1 and 3.7% in group 2. No statistically significant difference was noted between the two groups (all P > 0.05). CONCLUSION: Pin site care can be performed without impairing patient comfort and without prohibition of showering. Pin site care can be self-managed by the patients without complex sterilization techniques.