Andrew Hwee Chye Tan

Incidence of Clinically Significant Venous Thromboembolic Events in Asian Patients Undergoing Total Knee Arthroplasty Without Anticoagulation

This study aimed to evaluate the incidence of clinically significant venous thromboembolic events (VTE) in Asian patients undergoing total knee arthroplasty (TKA) without anticoagulation. All patients who underwent TKA by a single surgeon from 2006 to 2010 in Singapore General Hospital were reviewed. Only symptomatic patients were referred for ultrasonography. Of the 531 patients reviewed, 3 patients developed symptoms of deep vein thrombosis with subsequent ultrasonographic confirmation, whereas 1 patient developed fatal pulmonary embolism without any clinical or radiologic evidence of deep vein thrombosis. Hence, the incidence of clinically significant VTE was 0.75%. Given the low incidence of clinically significant VTE, there is a need to review the current practice of routine chemoprophylaxis in Asian patients undergoing TKA.

Epidemiology of surgically managed anterior cruciate ligament ruptures in a sports surgery practice

Introduction: Anterior cruciate ligament (ACL) tears are common knee injuries, especially among sportsmen and sportswomen. The aim of this study is to better understand the epidemiology of surgically managed ACL tears sustained in our institution. Methods: All patients who underwent arthroscopic ACL reconstruction by the senior author of this article in Singapore from 2008 to 2013 were studied. Patients who were diagnosed clinically and/or radiologically to have a complete tear of the ACL and subsequently underwent arthroscopic ACL reconstruction were included. Patients who suffered from traumatic knee dislocation were excluded. Two hundred and ninety-two patients were available for analysis. All patients were operated on by the senior author. Results: 83.9% of patients were male. 60.5, 23.0, 8.46, and 8.11% were of Chinese, Malay, Indian and other origins, respectively. 69.6 and 28.7% were in white-collared and blue-collared jobs, respectively, while 1.69% were unemployed. Mean age at operation was 29.4 years. Mean body mass index was 25.3 kg/m2. 82.4 and 17.6% of ACL tears were sports (contact—27.5%; non-contact—72.5%) and non-sports injuries (activities of daily living—94.2%, road traffic accidents—5.77%), respectively. The top four sporting activities causing ACL tears were soccer, basketball, racquet games and volleyball. 56.2% of ACL tears presented with concomitant knee injuries (medial meniscus—63.4%; lateral meniscus—31.1%; posterior cruciate ligament—5.49%). 84.5% were primary tears. Conclusions: In this epidemiological review of ACL injuries, we found that ACL injuries tend to cluster within certain population subgroups. Patterns of mechanisms of injuries have been observed. These findings may lead to better preventive and treatment strategies in the management of ACL tears.

Improvement in health-related quality of life after unilateral total knee arthroplasty in patients with bilateral knee osteoarthritis

Purpose To review the outcome of unilateral total knee arthroplasty (TKA) in patients with bilateral knee osteoarthritis (OA) to determine whether unilateral TKA can achieve good health-related quality of life (HRQoL). Methods Records of 68 women and 25 men with severe bilateral knee OA who underwent unilateral TKA on the more symptomatic knee by a single surgeon and did not return for the second TKA within 2 years were reviewed. Outcome at 6 months and 2 years was assessed using the mental and physical component summary (MCS and PCS) of the Short-Form 36 (SF-36) for HRQoL as well as the Oxford Knee Score (OKS) and Knee Society Score (KSS) for knee-specific outcome. Results The SF-36, OKS, and KSS improved significantly after unilateral TKA. Respectively for MCS and PCS of SF-36, OKS, and KSS knee and function scores, 65%, 89%, 98%, 98%, and 98% of patients reported absolute improvement at 2 years. Respectively for PCS, OKS, and KSS function score that a minimal clinically important difference (MCID) was established, 77%, 96%, and 80% of patients achieved MCID at 2 years. Conclusion Unilateral TKA achieves good outcome in HRQoL at 2 years in patients with bilateral knee OA.

Obesity and Venous Thromboembolism in Total Knee Arthroplasty Patients in an Asian Population

BACKGROUND Venous thromboembolism (VTE) is a known complication of total knee arthroplasty (TKA). In addition, obesity has been implicated as a risk factor and justification for chemoprophylaxis for VTE. We wanted to review the prevalence of VTE among our patients and evaluate the incidence rates of VTE among nonobese and obese patients. METHODS We reviewed 894 patients who underwent elective unilateral total knee arthroplasty by a single surgeon from March 2003 to November 2014 in our center. Any patients with clinically significant symptoms or signs of VTE such as deep venous thrombosis (DVT) or pulmonary embolism (PE) were diagnosed radiologically. The patient demographics analyzed included age, gender, body mass index, the number of comorbid diseases, and a history of hyperlipidemia. RESULTS We found the incidence of VTE of 0.67% in our patients (6 patients of 894). Four of the 6 patients (66.7%) who developed DVT and PE belonged to nonobese group. The frequency of VTE in nonobese patients was 0.65% and 0.73% in the obese patients. There were no significant differences in age, number of comorbidities, and a history of hyperlipidemia between those who developed DVT and PE and those who did not. CONCLUSION With the low prevalence of VTE among our study population, including patients with obesity, advanced age, multiple comorbidities, or hyperlipidemia, the practice of routine chemoprophylaxis should be reviewed.

Shoulder Impingement Syndrome, a Common Affliction of the Shoulder: A Comprehensive Review

The shoulder joint is the most mobile joint in the human body. It comprises a ball and socket structure that enables a series of functional movements to be carried out. These range from simple movements such as reaching for the top shelf to highly explosive overhead activities which involve throwing a baseball or serving with a tennis racquet as seen in athletes. Shoulder impingement syndrome (SIS) is one of the most common shoulder disorders seen in general practice. It is caused by a multitude of factors. Pathology can arise either from the rotator cuff tendon itself, structures external to this tendon or both in combination. The resultant shoulder pain with SIS not only causes distress but also limits the quality of life of patients. This article aims to provide a comprehensive review of the pathogenesis, aetiologies, clinical tests, investigations and management options for SIS based on current literature and research.

Outcomes of arthroscopic capsular release for the diabetic frozen shoulder in Asian patients

Introduction: Diabetic patients have been known to have a higher incidence of frozen shoulder. Arthroscopic capsular release has been described for diabetic frozen shoulder refractory to non-surgical treatment. We describe our single-surgeon experience of this procedure done in Asian patients presenting with diabetic frozen shoulder. Results: Data were prospectively collected from 25 patients from 2007 to 2008, who underwent arthroscopic capsular release for frozen shoulder with diabetes mellitus. This included the University of California–Los Angeles (UCLA) Shoulder Score by an independent observer. Mean follow-up duration was 44.3 ± 22 months with the age of 57.3 ± 10.9 years at the time of surgery. Mean duration of symptoms prior to surgery was 8.9 ± 7.5 months. Ten right shoulders and 15 left shoulders were operated on. Arthroscopic capsular release was performed in the beach chair position with the aid of a 90° electrocautery hook, from the rotator interval to posterior capsule. Significant improvement was observed in the UCLA scores post-operatively (preoperative total score 15.8 ± 3.6 vs. post-operative 33.3 ± 2.5, p < 0.00), including all domains of pain (3.9 ± 1.8 vs. 9.4 ± 0.9, p < 0.00), function (4.8 ± 1.7 vs. 9.4 ± 1.4, p < 0.00), active forward flexion (2.6 ± 0.7 vs. 4.6 ± 0.6, p < 0.00) and satisfaction (0.0 ± 0.0 vs. 5.0 ± 0.0, p < 0.00). No significant correlation between duration of symptoms and UCLA scores. Significant improvement was observed in forward flexion (preoperative 100.4 ± 18.8° vs. post-operative 157.6 ± 15.9°, p < 0.00) and external rotation (preoperative 14.4 ± 6.34° vs. post-operative 63.8 ± 8.3°, p < 0.00). Although the duration of symptoms correlated significantly with preoperative forward flexion (r = 0.443 and p < 0.027), there was no significant correlation with post-operative forward flexion (r = 0.023 and p < 0.91). No axillary nerve palsy observed. Conclusion: The diabetic frozen shoulder can be treated favourably with arthroscopic capsular release and the duration of symptoms prior to surgery does not affect the outcomes.

Arthroscopic management of posterior instability of the shoulder: A systematic review of predictive factors associated with poorer surgical outcomes

Introduction: We aimed to perform a systematic review to identify factors that may lead to poorer outcomes in arthroscopic surgery for posterior shoulder instability. Methods: We searched MEDLINE, Embase and the Cochrane Database of Systematic Reviews for 757 unique articles. We eventually included 22 articles. Data were analysed using Review Manager 5.3. Results: The presence of chondral damage was associated with poorer outcomes as reflected in a higher post-operative Quick Disabilities of theArm, Shoulder and Hand score (mean difference (MD) = 17.1; 95% confidence interval (CI) = 2.82–31.4; p = 0.02), higher WesternOntario Shoulder Instability (WOSI) index (MD = 468.0; 95% CI = 136.5–799.5; p = 0.006), lower Simple Shoulder Test score (MD = −2.40; 95% CI = −4.34 to −0.46; p = 0.02) and a lower Single Assessment Numeric Evaluation score (MD = −15.4; 95% CI = −30.6 to −0.23; p = 0.05). The presence of previous shoulder surgery was associated with poorer outcomes as depicted by a lower American Shoulder and Elbow Society (ASES) score (MD = −93.1; 95% CI = −96.9 to −89.3; p < 0.0001). The availability of workers’ compensation was associated with poorer outcomes as revealed by a lower rate of return to work (odds ratio (OR) = 0.02; 95% CI = 0.00–0.20; p = 0.0008). The presence of additional procedures while performing surgery for posterior shoulder instability was associated with poorer outcomes as reflected by lower ASES scores (MD = −6.70; 95% CI = −8.64 to −4.76; p < 0.0001), higher WOSI index (MD = 63.4; 95% CI = 33.0–93.8; p < 0.0001), lower University of California at Los Angeles (UCLA) scores (MD = −2.30; 95% CI = −2.81 to −1.79; p < 0.0001), higher pain scores (MD = 0.72; 95% CI = 0.39–1.05; p < 0.0001) and higher post-operative instability (MD = 0.80; 95% CI = 0.57–1.03; p < 0.0001). Conclusion: The presence of chondral damage, previous shoulder surgery, concomitant surgery and workman’s compensation was associated with poorer outcomes for arthroscopic repair of posterior shoulder instability. Further studies should be done to further validate these factors.

A Comparison of Clinical Outcomes of Two Methods of Femoral Hamstring Graft Pin Fixation in Anterior Cruciate Ligament Reconstruction

The outcome of anterior cruciate ligament (ACL) reconstruction with hamstring grafts depends on early rehabilitation and secure graft fixation. Various devices available for graft fixation at the femoral tunnel have different biomechanical properties as demonstrated on cadaveric studies. The aim of this study was to compare clinical outcomes in patients using either of two methods of transfemoral pin fixation for hamstring grafts in ACL reconstruction. Twenty-eight patients undergoing primary ACL reconstruction with hamstring autograft with either transfemoral expansion fixation (Rigidfix) or cortical-cancellous suspension (Transfix) by a single surgeon were analysed including subjective knee scores and objective measurements including range of motion and arthrometer-measured anterior translation. Transfix was used in 14 (50.0%) patients and Rigidfix was used in 14 (50.0%) patients. There was no significant difference in pre-injury Tegner activity scores, pre-operative Tegner activity scores, Lysholm scores and age or in Tegner post-operative activity scores, Lysholm scores, range of motion, Lachman and pivot scores absolute anterior translation and anterior translation compared to the non-operated knee at two years. There was a significant improvement in Tegner (2.6 ± 2.4, p<0.00) and Lysholm (25.3 ± 21.2, p<0.00) scores at two years with no significant difference between the two groups. One patient had a broken Transfix cross-pin 13 months after surgery which presented as a subcutaneous swelling which was removed. Although the biomechanical properties of Rigidfix and Transfix differ as demonstrated in cadaveric studies, both devices had similar favourable clinical outcomes in our series.

Surgical site infection after primary total knee arthroplasty is associated with a longer duration of surgery

Purpose: Surgical site infection (SSI) is a serious complication following total knee arthroplasty (TKA) leading to considerable morbidity. The incidence is reported to be up to 2%. Risk factors continue to be an area of intense debate. Our study aims to report the incidence of SSI and identify possible risk factors in our patients undergoing TKA. Methods: Prospectively collected data for 905 patients who underwent elective unilateral TKA by a single surgeon from February 2004 to July 2014 were reviewed. Patient demographics and relevant co-morbidities such as diabetes and heart disease were analysed. The presence of superficial wound infections and/or prosthetic joint infections was included. Results: The overall infection rate was 1.10% (10 of 905 patients). Six patients (0.66%) were diagnosed with superficial infections and four with PJI (0.44%). The mean operative duration for TKA with SSI was significantly longer at 90.5 ± 28.2 min, compared to 72.2 ± 20.3 min in TKA without SSI (p = 0.03). All superficial infections occurred within the first month post-surgery and were self-limiting with oral antibiotics. The four patients with PJI required repeated procedures following TKA, including debridement, implant removal and/or revision arthroplasty. None of the 10 patients had a history of diabetes. There were no significant differences in demographics and co-morbidities between those who developed infection after TKA and those who did not. Conclusion: An overwhelming majority had good outcomes with only four deep infections resulting in revision surgery. We report that the risk of infection in TKA was significantly associated with a longer operative duration.