Arthroscopic Knee Surgery Research Articles

Association between meniscal tear patterns and self-reported knee osteoarthritis 5 years after meniscal surgery

Purpose: Patients with meniscal tears having knee arthroscopic surgery of the meniscus are at high risk of developing knee osteoarthritis (OA). Specific meniscal tear patterns such as horizontal and complex tears are typically observed in middle-aged and older patients and often in combination with OA. In contrast, younger patients more often have longitudinal-vertical tears in an otherwise healthy knee joint. Thus, patients with specific meniscal tear patterns may be at higher risk of developing knee OA than others.

Additional Factors in Evaluating Opioid Use following Arthroscopic Knee Surgery

Additional Factors in Evaluating Opioid Use following Arthroscopic Knee Surgery

Incisionless Partial Medial Meniscectomy

Knee arthroscopy has evolved greatly from its inception in the twentieth century. Of the many arthroscopic knee surgeries, meniscectomy is the most commonly performed. Arthroscopic meniscectomy is the most common orthopaedic surgical procedure performed in the United States. We continue to develop more minimally invasive procedures, and the NanoScope has provided a new generation of possibilities. The system does not require the use of a standard incision or portal, and with the use of nanoinstruments, we can perform treatments as well as diagnostic arthroscopy without incisions. This technique provides an updated incisionless option to perform a partial medial meniscectomy.

BUTTER PAPER AS A COST EFFECTIVE DRESSING FOR SUPERFICIAL INTERMEDIATE THICKNESS BURN

Introduction Post-operative pain is very common distressing symptom after any surgical procedure.Different drugs in different routes have been used for controlling post-arthroscopic pain.We have compared the efficacy of analgesic effect of plain ropivacaine versus ropivacaine with dexmedetomidine as an adjuvant when administered through the intra-articular route in arthroscopic knee surgery. Materials and Methods From June 2017 to June 2019 sixty patients undergoing elective knee arthroscopy were randomly assigned to two groups (n=30). Group R received 19 ml of 0.50% ropivacaine and 1 ml of isotonic saline (total volume 20 ml) intraarticularly. Group RD received 100 μg (1 ml) of dexmedetomidine added to 19 ml of 0.50% ropivacaine intra-articularly(total 20ml).Pain was assessed using visual analogue scale(VAS) and diclofenac sodium given as rescue analgesia when VAS>4.Time of first analgesia request and total dose of rescue analgesics used in 24 hours were calculated. Results VAS score were significantly lower in Group RD, time to first analgesic requirement was significantly greater in Group RD than in Group R and total dose of analgesics used in Group RD patients was significantly less compared to patients in Group R. Conclusion Dexmedetomidine, added as adjunct to ropivacaine in patients undergoing arthroscopic knee surgery, improves the quality and duration of postoperative analgesia.

Risk Factors for Early Total Knee Replacement after Ipsilateral Knee Arthroscopy in Patients over 55 Years of Age

Arthroscopic knee surgery (AKS) is often not successful in elderly patients with osteoarthritis and degenerative meniscus tears. Many patients require subsequent total knee replacement (TKR). We performed a case-control study to identify risk factors for early TKR following AKS in patients over 55. Data were collected on patients in an integrated healthcare system who underwent AKS between January 2010 and December 2012, and then had ipsilateral total knee replacement (TKR) within one year. Controls were matched from patients who did not have TKR within one year. Of the 7,301 AKS patients, 453 (6.2%) went on to TKR. We matched 390 cases with controls (780 total subjects); 186 subjects were excluded due to inadequate radiographs or medical records resulting in a cohort of 594 patients. Statistical analysis showed that a Kellgren-Lawrence score of 3 or 4 (OR 1.9 CI 1.3-2.8, p < 0.01), age greater than 65 (OR 2.2, CI 1.5-3.2, p < 0.01), contralateral TKR (OR 2.3, CI 1.1-5.0, p < 0.04) were associated with a higher likelihood of early TKR. Sex, race, diagnosis of diabetes, prior ipsilateral knee surgery, and prior contralateral knee surgery were not associated with early TKR. When considering AKS for older patients with degenerative arthritis and meniscus tears, care providers should consider the risk of early TKR. Older patients with advanced arthritis and a diagnosis of osteoarthritis, or combined with a meniscus tear, are especially at risk for early TKR.

Knee Arthroscopic Surgery in Middle-Aged Patients With Meniscal Symptoms: A 5-Year Follow-up of a Prospective, Randomized Study

Background:Arthroscopic meniscal surgery is a common orthopaedic procedure in middle-aged patients, but the efficacy of this procedure has been questioned. In this study, we followed up the only randomized controlled trial that has shown a 1-year benefit from knee arthroscopic surgery with an exercise program compared with an exercise program alone.Purpose:To (1) evaluate whether knee arthroscopic surgery combined with an exercise program provided an additional 5-year benefit compared with an exercise program alone in middle-aged patients with meniscal symptoms, (2) determine whether baseline mechanical symptoms affected the outcome, and (3) compare radiographic changes between treatment groups.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:Of 179 eligible patients aged 45 to 64 years, 150 were randomized to either a 3-month exercise program (nonsurgery group) or to the same exercise program plus knee arthroscopic surgery (surgery group) within 4 weeks. Radiographs were assessed, according to the Kellgren-Lawrence grade, at baseline and at the 5-year follow-up. The primary outcome was the change in Knee injury and Osteoarthritis Outcome Score (KOOS)–Pain (KOOSPAIN) subscore from baseline to the 5-year follow-up. We performed an as-treated analysis.Results:A total of 102 patients completed the 5-year questionnaire. At the 5-year follow-up, both groups had significant improvement in KOOSPAIN subscores, although there was no significant change from the 3-year scores. There was no between-group difference in the change in the KOOSPAIN subscore from baseline to 5 years (3.2 points [95% CI, –6.1 to 12.4]; adjusted P = .403). In the surgery group, improvement was greater in patients without mechanical symptoms than in those with mechanical symptoms (mean difference, 18.4 points [95% CI, 8.7 to 28.1]; P < .001). Radiographic deterioration occurred in 60% of patients in the surgery group and 37% of those in the nonsurgery group (P = .060).Conclusion:Knee arthroscopic surgery combined with an exercise program provided no additional long-term benefit after 5 years compared with the exercise program alone in middle-aged patients with meniscal symptoms. Surgical outcomes were better in patients without mechanical symptoms than in patients with mechanical symptoms during the preoperative period. Radiographic changes did not differ between treatment groups.Registration:NCT01288768 (ClinicalTrials.gov identifier).

Evaluation of the Early Functional Outcome Following Arthroscopic Partial Meniscectomy for Meniscal Tears

Meniscal tears are among the common knee pathologies which affect activities of daily living if not managed properly. Arthroscopic knee surgery is an evolving procedure in our environment and patient satisfaction with this procedure needs to be evaluated. This was a prospective study carried out between June 2017 and May 2018 with the aim to determine the effectiveness of Arthroscopic Partial Meniscectomy in the management of meniscal tears in our environment. The Western Ontario Meniscal Evaluation Tool (WOMET) Knee Score was used to assess patient satisfaction with this procedure. A total of thirty-one patients were recruited into the study consisting of eighteen males and thirteen females with an average age of thirteen years (17 - 48 years) who underwent arthroscopic partial meniscectomy. Preoperative and postoperative knee scores at 6 weeks and 12 weeks were compared using the Western Ontario Meniscal Evaluation Tool. At the end of the study period, data collated were analyzed using the specified tools. In terms of clinical outcomes, arthroscopic partial meniscectomy showed statistically significant improvement of symptoms as evidenced by a mean knee score of 75.6 (SD 9.3) at 6 weeks, 87.7 (SD 4.7) at 12 weeks compared with a preoperative knee score of 46.7. Medial meniscal tears were more common than lateral meniscal tears in all age groups and both sexes recruited into the study. The most common type of meniscal tear seen was the longitudinal type of tear while complex tear is the least type of tear seen. The surgery (arthroscopic partial meniscectomy) is an evolving area of sports medicine that requires sub-specialization, however solves the problem of increased mobility following open surgery. This study will tend to add to existing knowledge as patients who are mostly sports inclined can return to play very early with better outcome scores as regards pain and function.

The efficacy of intra-articular fentanyl supplementation for knee arthroscopy: A meta-analysis of randomized controlled studies.

The efficacy of intra-articular fentanyl supplementation for pain control after knee arthroscopy remains controversial. We conduct a systematic review and meta-analysis to explore the influence of intra-articular fentanyl supplementation for pain intensity after arthroscopic knee surgery. We searched PubMed, EMbase, Web of Science, EBSCO, and Cochrane Library databases through May 2019 for randomized controlled trials (RCTs) assessing the efficacy and safety of intra-articular fentanyl supplementation for arthroscopic knee surgery. This meta-analysis is performed using the random-effects model. Four RCTs are included in the meta-analysis. Overall, compared with control group after knee arthroscopy, intra-articular fentanyl supplementation is associated with reduced pain scores at 1 h (standard mean difference (Std MD) = -3.50; 95% confidence interval (CI) = -5.68 to -1.32; p = 0.002), 2 h (Std MD = -4.73; 95% CI = -8.75 to -0.71; p = 0.02), and 8 h (Std MD = -5.02; 95% CI = -9.73 to -0.30; p = 0.04) but shows no substantial impact on pain scores at 4 h (Std MD = -3.94; 95% CI = -7.93 to 0.05; p = 0.05) or the supplementary analgesia (risk ratio = 0.56; 95% CI = 0.09-3.59; p = 0.54). Intra-articular fentanyl supplementation does benefit in pain control after knee arthroscopy.

Efficacy of Intra-Articular Dexmedetomidine for Postoperative Analgesia in Arthroscopic Knee Surgery

Introduction Post-operative pain is very common distressing symptom after any surgical procedure.Different drugs in different routes have been used for controlling post-arthroscopic pain.We have compared the efficacy of analgesic effect of plain ropivacaine versus ropivacaine with dexmedetomidine as an adjuvant when administered through the intra-articular route in arthroscopic knee surgery. Materials and Methods From June 2017 to June 2019 sixty patients undergoing elective knee arthroscopy were randomly assigned to two groups (n=30). Group R received 19 ml of 0.50% ropivacaine and 1 ml of isotonic saline (total volume 20 ml) intraarticularly. Group RD received 100 μg (1 ml) of dexmedetomidine added to 19 ml of 0.50% ropivacaine intra-articularly(total 20ml).Pain was assessed using visual analogue scale(VAS) and diclofenac sodium given as rescue analgesia when VAS>4.Time of first analgesia request and total dose of rescue analgesics used in 24 hours were calculated. Results VAS score were significantly lower in Group RD, time to first analgesic requirement was significantly greater in Group RD than in Group R and total dose of analgesics used in Group RD patients was significantly less compared to patients in Group R. Conclusion Dexmedetomidine, added as adjunct to ropivacaine in patients undergoing arthroscopic knee surgery, improves the quality and duration of postoperative analgesia.

Opioid-Limiting Regulation: Effect on Patients Undergoing Knee and Shoulder Arthroscopy

To determine the effect prescription-limiting legislation passed in Rhode Island has had on opioids prescribed following arthroscopic knee and shoulder surgery at various time points, up to 90 days postoperatively. All patients undergoing the 3 most common arthroscopic procedures at our institution (anterior cruciate ligament reconstruction, partial meniscectomy, and rotator cuff repair) were included. Patients were selected from 2 6-month study periods (prepassage and postimplementation of the law). The state's Prescription Drug Monitoring Program database was queried for controlled substances filled in the perioperative period (from 30 days preoperatively to 90 days postoperatively). Multiple logistic regressions were used to identify predictors of chronic (>30 days) opioid use. The morphine milligram equivalents (MMEs) prescribed in the initial postoperative script decreased from 319.04 (∼43 5-mg oxycodone tablets) in the prepassage to 152.45 MMEs (∼20 5-mg oxycodone tablets) in the postimplementation group (P < .001). The total MMEs filled in the first 30 days decreased from 520.93 to 299.94 MMEs (∼70 to ∼40 5-mg oxycodone tablets) (P < .001). MMEs filled between 30 and 90 days fell by 22.5% for all patients in this study; however, this change was not statistically significant (P= .263). Preoperative opioid use (odds ratio, 10.85; P < .001) and preoperative benzodiazepine use (odds ratio, 2.13; P= .005) predicted chronic opioid use postoperatively. State opioid-limiting legislation reduced cumulative MMEs following arthroscopic knee and shoulder surgery in the first 30 days. Further research assessing the impact of this legislation on postoperative pain control, patient satisfaction, and functional outcomes following surgery is warranted. Level III, case-control study.

Opioid Requirement following Arthroscopic Knee Surgery: Are There Predictive Factors Associated with Long-Term Use.

The purpose of this study is to identify patterns of postoperative narcotic use and determine the impact of psychosocial and perioperative factors on postoperative opioid consumption following arthroscopic knee surgery. Fifty consecutive patients undergoing arthroscopic knee surgery were prospectively enrolled. Patients were contacted via telephone at 1 week postoperatively to report their pain level and opioid consumption. The patient was contacted again at 2 weeks, 4 weeks, and 90 days as necessary until opioid cessation, at which time the patient's plan for unused pills was inquired. Opioid consumption was compared using t-tests and one-way analysis of variance for demographic and surgical factors. Linear regression was used to determine whether the Pain Catastrophizing Scale (PCS), Resilience Scale (RS-11), International Knee Documentation Committee questionnaire, or patient-reported pain at 1 week predicted higher opioid consumption. The average morphine equivalent dose of opioid consumption was 142 mg. Sixty-four percent consumed less than 100 mg, and 68% discontinued opioid use by 1 week postoperatively. Seventy-four percent reported surplus pills, and 49% of those patients plans for pill disposal. Factors associated with higher consumption included undergoing a major procedure, having a regional anesthesia block, and higher area deprivation index score (p < 0.05). Higher PCS scores and reported average pain level at 1 week were predictive of higher opioid consumption (p < 0.05). In conclusion, a majority of patients undergoing outpatient knee surgery did not require the entirety of their narcotic prescription. The majority of patients consumed less than 100 mg of morphine equivalents and discontinued opioid use by 1 week postoperatively. Ligament reconstruction, living in an area with a higher index of deprivation, and higher score on the PCS were associated with greater opioid consumption. Overall, patient knowledge regarding opioid disposal was poor, and patients would likely benefit from additional education prior to surgery.

Temporal trends and regional variation in the rate of arthroscopic knee surgery in England: analysis of over 1.7 million procedures between 1997 and 2017. Has practice changed in response to new evidence?

ObjectivesWe investigated trends and regional variation in the rate of arthroscopic knee surgery performed in England from 1997–1998 to 2016–2017.DesignCross-sectional study of the national hospital episode statistics (HES) for England.MethodsAll...

Comparison of postoperative analgesia after intraarticular injection of two different doses of morphine (5 mg) and Morphine (10 mg) with 0.5% bupivacaine in arthroscopic knee surgery : Randomized, double blinded prospective study

Comparison of postoperative analgesia after intraarticular injection of two different doses of morphine (5 mg) and Morphine (10 mg) with 0.5% bupivacaine in arthroscopic knee surgery : Randomized, double blinded prospective study - IJCA- Print ISSN No: - 2394-4781 Online ISSN No:- 2394-4994 Article DOI No:- 10.18231/j.

The characteristic arthroscopic 'eyelid- turnup' sign indicated for partial-thickness longitudinal medial meniscus tear.

Medial posterior horn meniscal tear is difficult to be visualized in full view during arthroscopy and is occasionally undetected when the superior surface seems intact. The purpose of this study is to describe a characteristic arthroscopic sign indicating the occult partial-thickness longitudinal medial meniscus tear extending only to the inferior articular surface. This study was a retrospective analysis of available arthroscopic knee surgery between January 2016 and December 2017. The videos were studied and data was recorded for the number of cases showing the presence of 'eyelid-turnup' sign and coexisting partial-thickness medial meniscus tear. Sensitivity and positive predictive value of the sign were calculated. Of all the 491 videos of medial meniscal tear available for review, partial-thickness longitudinal medial meniscus was torn in 26 cases. Six out of 26 patients could be diagnosed with partial-thickness longitudinal tear under direct vision. Of the other 20 patients which could not be diagnosed under direct vision during arthroscopy until the tear was pressed by a probe, 17 patients were diagnosed by the positive 'eyelid-turnup' sign. The other 3 patients showed negative 'eyelid-turnup' sign and were then diagnosed by the hints of preoperative MRI and intra-operative exploration. The sensitivity of the sign was 85%; the positive predictive value was 89.5%. The 'eyelid-turnup' sign of meniscus pressed by a probe at arthroscopy is a characteristic indicator for occult inferior partial-thickness longitudinal tears of midbody and posterior horn. Early identification of this special sign may help reduce the likelihood that the occult partial-thickness longitudinal tear will be missed during arthroscopy.

Quadriceps Neuromuscular Impairments after Arthroscopic Knee Surgery: Comparison between Procedures.

Quadriceps neuromuscular function remains impaired in the short- and long-term following knee arthroscopy for meniscal surgery and/or anterior cruciate ligament (ACL) reconstruction. The aim of this study was to compare quadriceps neuromuscular impairments in patients following meniscal surgery with and without ACL reconstruction. Thirty patients were tested six months after meniscal surgery with (n = 15) and without (n = 15) ACL reconstruction. We bilaterally assessed knee extension maximal voluntary contraction (MVC) torque using dynamometry, vastus lateralis thickness using ultrasound, quadriceps voluntary activation and evoked knee extension torque with transcutaneous electrical stimulation. Patient-reported outcomes were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS). Compared with meniscus patients, ACL patients demonstrated larger asymmetries in MVC torque (15% vs. 5%, p = 0.049) and vastus lateralis thickness (6% vs. 0%, p = 0.021). In ACL patients, asymmetries in MVC torque correlated with asymmetries in evoked torque (r = 0.622, p = 0.013). In meniscus patients, asymmetries in muscle activation correlated with KOOS quality of life (r = 0.619, p = 0.018). Patients demonstrated persistent quadriceps muscle weakness six months after ACL reconstruction, but not after isolated meniscal surgery. Quantitative and/or qualitative muscular changes likely underlie quadriceps muscle weakness in ACL patients, whereas activation failure is associated with poor quality of life in some meniscus patients.

Complications in knee surgery

This is a comprehensive review of complications that can occur with common knee surgical procedures. Procedures have been grouped into arthroscopic & soft-tissue knee surgery, articular cartilage restoration procedures, osteotomy, and arthroplasty. As newer implants and procedures are developed it is anticipated that new complications may arise. However, the overall trend will be towards a generalized reduction. At the same time, patient expectations are increasing in tandem with improvements in health and longevity. It is important to counsel patients regarding any risks of potential complications associated with any intervention as part of the informed consent process.

Adductor canal blocks for postoperative pain treatment in adults undergoing knee surgery.

Peripheral regional anaesthesia techniques are well established for postoperative pain treatment following knee surgery. The adductor canal block (ACB) is a new technique, which can be applied as a single shot or by catheter for continuous regional analgesia. To compare the analgesic efficacy and adverse events of ACB versus other regional analgesic techniques or systemic analgesic treatment for adults undergoing knee surgery. We searched CENTRAL, MEDLINE, and Embase, five other databases, and one trial register on 19 September 2018; we checked references, searched citations, and contacted study authors to identify additional studies. We included all randomized controlled trials (RCTs) comparing single or continuous ACB versus other regional analgesic techniques or systemic analgesic treatment. Inclusion was independent of the technique used (landmarks, peripheral nerve stimulator, or ultrasound) and the level of training of providers. We used Cochrane's standard methodological procedures. Our primary outcomes were pain intensity at rest and during movement; rate of accidental falls; and rates of opioid-related adverse events. We used GRADE to assess the quality of evidence for primary outcomes. We included 25 RCTs (1688 participants) in this review (23 trials combined within meta-analyses). In 18 studies, participants underwent total knee arthroplasty (TKA), whereas seven trials investigated patients undergoing arthroscopic knee surgery. We identified 11 studies awaiting classification and 11 ongoing studies. We investigated the following comparisons. ACB versus sham treatment We included eight trials for this comparison. We found no significant differences in postoperative pain intensity at rest (2 hours: standardized mean difference (SMD) -0.56, 95% confidence interval (CI) -1.20 to 0.07, 4 trials, 208 participants, low-quality evidence; 24 hours: SMD -0.49, 95% CI -1.05 to 0.07, 6 trials, 272 participants, low-quality evidence) or during movement (2 hours: SMD -0.59, 95% CI -1.5 to 0.33; 3 trials, 160 participants, very low-quality evidence; 24 hours: SMD 0.03, 95% CI -0.26 to 0.32, 4 trials, 184 participants, low-quality evidence). Furthermore, they noted no evidence of a difference in postoperative nausea between groups (24 hours: risk ratio (RR) 1.91, 95% CI 0.48 to 7.58, 3 trials, 121 participants, low-quality evidence). One trial reported that no accidental falls occurred 24 hours postoperatively (low-quality evidence). ACB versus femoral nerve block We included 15 RCTs for this comparison. We found no evidence of a difference in postoperative pain intensity at rest (2 hours: SMD -0.74, 95% CI -1.76 to 0.28, 5 trials, 298 participants, low-quality evidence; 24 hours: SMD 0.04, 95% CI -0.09 to 0.18, 12 trials, 868 participants, high-quality evidence) or during movement (2 hours: SMD -0.47, 95% CI -1.86 to 0.93, 2 trials, 88 participants, very low-quality evidence; 24 hours: SMD 0.56, 95% CI -0.00 to 1.12, 9 trials, 576 participants, very low-quality evidence). They noted no evidence of a difference in postoperative nausea (24 hours: RR 1.22, 95% CI 0.42 to 3.54, 2 trials, 138 participants, low-quality evidence) and no evidence that the rate of accidental falls during postoperative care was significantly different between groups (24 hours: RR 0.20, 95% CI 0.04 to 1.15, 3 trials, 172 participants, low-quality evidence). We are currently uncertain whether patients treated with ACB suffer from lower pain intensity at rest and during movement, fewer opioid-related adverse events, and fewer accidental falls during postoperative care compared to patients receiving sham treatment. The same holds true for the comparison of ACB versus femoral nerve block focusing on postoperative pain intensity. The overall evidence level was mostly low or very low, so further research might change the conclusion. The 11 studies awaiting classification and the 11 ongoing studies, once assessed, may alter the conclusions of this review.

Impact of smoking on outcomes following knee and shoulder arthroscopy.

The purpose of this study is to evaluate any association between preoperative smoking and perioperative and early postoperative complications in patients following shoulder and knee arthroscopic surgery. This is a retrospective study using the prospectively collected National Surgery Quality Improvement Program database. All patients who underwent eight specific shoulder and knee arthroscopy procedures, identified by current procedural terminology codes, were included in this study and analyzed using univariate and multivariate analyses to determine the impact of preoperative smoking status on postoperative complications. These procedures were knee arthroscopy with meniscectomy (medial or lateral), knee arthroscopy with meniscectomy (medial and lateral), knee arthroscopy with chondroplasty, knee arthroscopy with anterior cruciate ligament reconstruction, shoulder arthroscopy with subacromial decompression, shoulder arthroscopy with debridement, subacromial arthroscopy with rotator cuff repair, and shoulder arthroscopy with distal clavicle excision. Thirty-day complications including cardiac, renal, wound, pulmonary, clotting, and mortality were assessed following knee and shoulder arthroscopy. A total of 134,822 cases were included in the study. Multivariate analysis found that smoking was an independent risk factor for complications in shoulder arthroscopy with subacromial decompression (odd's ratio [OR] = 1.46; 95% confidence interval [CI] 1.030-2.075), shoulder arthroscopy with debridement (OR = 1.933; 95% CI 1.211-3.084), and knee arthroscopy with medial and lateral meniscectomy (OR = 1.97; 95% CI 1.407-2.757). Smoking was not an independent risk factor for complications in the other five procedures studied. Preoperative smoking was found to be an independent risk factor for complications for several arthroscopic procedures, though with variability between specific procedures.

Early preoperative versus postoperative administration of meloxicam in pain control, patient global status improvement, knee function recovery of arthroscopic knee surgery.

This study aimed to investigate the efficacy and safety between early preoperative administration and postoperative administration of oral meloxicam in patients underwent arthroscopic knee surgery (AKS). Totally 296 patients with the intention to undergo AKS were recruited and randomly allocated as 1:1 ratio into early preoperative analgesia (EPA) group and postoperative analgesia (POA) group. Pain visual analog scale (VAS) score and severity (at rest and at flexion), patient global assessment (PGA) score, the consumption of rescue analgesia (pethidine), and adverse events were evaluated during the perioperation. And knee range of motion (ROM), International Knee Documentation Committee (IKDC) score, and Lysholm score were assessed at baseline and at 3 months after AKS. Both pain VAS score and severity (at rest and at flexion) were decreased at 4, 8, and 12 hours, but similar at -24, -2, 24, 36, and 48 hours after AKS in EPA group compared with POA group. Besides, PGA score was lower at 4, 8, 12, and 24 hours, but similar at -24, -2, 36, and 48 hours after AKS in EPA group compared with POA group. As to the consumption of pethidine in perioperative period, it was decreased in EPA group compared with POA group. No difference was observed in knee ROM, IKDC score, Lysholm score, and adverse effects between EPA group and POA group. Early preoperative administration of meloxicam was a superior approach in pain control compared with postoperative administration in treating patients underwent AKS.

Stability enhanced variable selection for a semiparametric model with flexible missingness mechanism and its application to the ChAMP study

ABSTRACT This paper is motivated by the analytical challenges we encounter when analyzing the ChAMP (Chondral Lesions And Meniscus Procedures) study, a randomized controlled trial to compare debridement to observation of chondral lesions in arthroscopic knee surgery. The main outcome, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain score, is derived from the patient's responses to the questionnaire collected in the study. The major goal is to identify potentially important variables that contribute to this outcome. In this paper, the model of interest is a semiparametric model for the pain score. To address the missing data issue, we adopt a flexible missingness mechanism that is much more versatile in practice than a single parametric model. Then we propose a pairwise conditional likelihood approach to estimate the unknown parameter in the semiparametric model without the need of modeling its nonparametric counterpart nor the missingness mechanism. For variable selection, we apply a regularization approach with a variety of stability enhanced tuning parameter selection methods. We conduct comprehensive simulation studies to evaluate the performance of the proposed method. We also apply the proposed method to the ChAMP study to demonstrate its usefulness.