Background: UKA and HTO are suitable alternatives to TKA in younger patients. The indications for UKA and HTO overlap. Therefore, greater understanding of the indications for each procedure is required. Methods: A systematic review was performed to compare HTO to UKA in respect to functional outcomes, prosthesis survival, perioperative outcome and revision rates. Results: 2065 knees from 13 studies were included in the analysis, 1075 HTO and 990 UKA. Three studies reported superior activity sports sub-scale scores at greater than 24 months following HTO. HTO patients also returned to impact sport sooner. Koh et al and Bouguennec et al demonstrated superior Western Ontario and McMaster Universities arthritis Index scores at final follow-up following UKA. Petersen et al saw superior Knee Injury and Osteoarthritis Outcome Score pain, symptoms and QoL sub-scale scores at 93.6 months among UKA patients. Zhao et al reported superior Visual Analogue Scale for pain scores and Hospital for Special Surgery Knee-rating Scale (HSS) at 24-months post-op. Cho et al. reported superior HSS in older UKA patients (67.9 ± 9.0 yrs) in comparison to a significantly younger HTO cohort at 39.7 ± 14.0 months. Ten year survivorship was similar between HTO and UKA (74.2%-91% vs 71-87.1%). Revision rates to TKA for both procedures were comparable to large registry studies. Indication for revision was most commonly progression of OA following HTO and prosthesis related following UKA. Conclusions: Both HTO and UKA are effective alternatives to TKA for isolated, medial compartment OA in the hands of specialist, high volume surgeons.

Platelet rich plasma has been purported as a safe alternative in Younger patients with lower grade of Articular degeneration, with potential to reduce pain and improve Knee function & quality of Life. A total of 54 patients with grade one or two arthritis according to Kellgren and Lawrence system were enrolled in the study.Double spin technique was used for extraction of PRP. All 54 patients received Platelet rich plasma injections at 0, 2weeks and 6weeks. . Out of the 54 patients, 4 were lost to follow up and hence one year follow up was possible for 50 patients. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Scoring system was used to evaluate the condition of patients, including pain, stiffness, and physical functioning of the joints. VAS scoring system was used for evaluation of pain. Assessment was done at three weeks, six weeks, six months and one year. There was a statistically significant improvement in WOMAC and VAS scores at three months and six months, however the effect was not sustained at one year. We conclude that although platelet rich plasma injection helps in the short term the long-term effects might not be very conclusive.

Introduction: Osteoarthritis is age related degenerative arthritis due to wear and tear phenomenon. Knee joint arthritis usually presents as a medial compartment involvement. Material and Methods: 113 patients of osteoarthritis of knee joint were treated with open wedge high tibial osteotomy from April 2005 to Decemeber 2017. There were 28 male and 85 female. 33 patients had both side osteotomy. Their age ranged from 46 to 89 years (average 57.5 years). All patients presented with classical features of OA along with varying degree (6 to 19º) of varus deformity. Deformities were corrected with medial open wedge osteotomy. Appropriate size iliac graft was placed at osteotomy site. The osteotomy was fixed with tibial head buttress plate in 9º valgus. The patient was mobilized with progressive weight wearing form next postoperative day. Results: Arthritic pain disappeared just after surgery. All except 2 patients regained the preoperative range of motion. All osteotomies healed. Five patients developed infection. Plate had to be removed in two patients. 90% patients were satisfied with the procedure. Poor results were seen in joints which were having significant associated ligaments laxity, under correction, post-op loss of correction and infection Discussion: Medial open wedge high tibial osteotomy is technically a simple procedure and financially a significantly cheaper option and a viable option as compared to replacement surgery as viable alternative to total knee joint replacement surgery in selected cases of OA, particularly in Asian countries where squatting and cross legged knee activities are required in their day to day life.

Introduction
An increasing number of working adults undergo knee arthroplasty in Singapore. There is limited data concerning Southeast Asian patients returning to work (RTW) following surgery. Our aim was to identify and study factors influencing patients who RTW following total (TKR) or unicondylar knee replacement (UKR).

Methods
Patients who underwent TKR or UKR between August 2017 to March 2020 in our center were included in this study. Outcomes include RTW, duration prior to RTW, and RTW of the same nature.

Results
441 patients underwent TKR (295 women, 146 men, mean age 67.3 years) and 69 underwent UKR (48 women, 21 men, mean age 61.1 years). Patients who underwent TKR returned to work earlier (mean 83.7 ± 27.1 days) compared to UKR (mean 94.4 ± 42.3 days). 90.0% of TKR patients RTW compared to 95.5% who underwent UKR. Of patients who RTW, 94.3% of the TKR group returned to employment of the same nature compared to 92.9% of UKR patients.

Patients who RTW were of a younger age (p = 0.03), white collared workers (p = 0.04), and had independent pre-operative ambulatory status (p <0.01).

Patients who RTW of the same nature were of the subsidized paying class (p <0.01) and had better post-operative Knee Society Scores (p = 0.04).

Conclusion
Younger and independently ambulating patients may have better capacity for rehabilitation and RTW post arthroplasty surgery.

Introduction: The incidence of neuropathic changes following total knee arthroplasty and its effect on patient satisfaction remains poorly documented. Our aim was to document the incidence of infrapatellar nerve injury following total knee arthroplasty and its effect on patient satisfaction. Methods: Our retrospective study included 120 total knee replacements. Screening of sensory abnormalities was assessed by the DN4 score and the drawing of the topography of sensory disorders in all patients. The functional evaluation was performed by the IKDC score. Results: In this study, we reviewed 98 patients. The mean age was 65.2±7.7 years. We included 79 women and 19 men with a sex ratio of 0.23. The indication of total knee arthroplasty was degenerative osteoarthritis in 95% and osteoarthritis secondary to rheumatoid arthritis in 5%. The incidence of peripatellar neuropathy was noted in 68.3% of patients, regardless of the approach used (antero-medial and sagittal) and the length of the approach. We found a statistically significant correlation between satisfaction and dynamic mechanical pain, also between anterior knee pain and the incidence of altered sensations with p <0.05. Four of our patients felt that an alteration of the skin sensation was a determinant factor in their dissatisfaction. Conclusions: Sensory changes due to the damage of the infrapatellar branch of the saphenous nerve during total knee joint arthroplasty is a common occurrence and can interfere with patient satisfaction. We recommend that patients should be informed of this risk during the preoperative discussion.

Introduction About 10%-20% of patients with gonarthrosis have degenerative disease of the knee with valgus deformity. The arthroplasty technique imposes some particularities due to: the complexity of the capsular-ligamentous apparatus, the used approach, bone stock deficiency ,the alignment of the prosthesis components, the difficulty of obtaining a ligament balance. Methods The study includes the treatment of 60 patients with degenerative knee diseases who underwent a total knee arthroplasty during the years 2004-2019. The average age at which they were operated is 63.6 years old. Until the surgery the angle of the valgus deformity was 18°(13°-30°). We used the primary prosthesis with posterior stabilization in 49 cases. In 11 cases used over-stabilized prosthesis. For preoperative evaluation of the degree of osteoarthritis we use the Ahlback Radiological Classification. Results Obtaining a ligament balance in valgus knee arthroplasty is extremely complicated due to the retraction of the lateral capsulo-ligamentous apparatus and the medial compartment laxity, therefore, in deformities greater than 20 ° it is recommended to use revision prosthesis which was performed in 11 patients. The clinical evaluation was performed according to the IKSS Score, 28 points were accumulated preoperative and 89 points postoperative. Conclusion A rigorous patients selection, a correct preoperative planning performance, surgical techniques observance according to the algorithm, accurate ligament balancing allow us
obtaining good functional results in most cases. The IKSS score increased from 28 points, preoperative, to 89-postoperative.Valgus deformities with misalignment greater than 20 degrees and ligament instability require the application of over-stabilized prosthesis. Keywords Knee arthroplasty, valgus.

Introduction: Periprosthetic joint infection (PJI) is one of the most challenging and frequent complications after lowerextremity joint (hip and knee) arthroplasty. despite all the advances in this field, it is still a real concern with immense impact on patients, and the healthcare system. Methods: We performed a randomized single-blind clinical trial study. A total of 059 gloves were collected from 109 primary total hip arthroplasties. Gloves were analysed by water-leak test; EN455-1 determined the perforation. Result: Demographic factors and comorbid conditions associated with an increased adjusted risk of PJI. The average occurrence of perforation was 60 minutes after the beginning of surgery. The sites of perforation were localized mostly on the Index finger. The overall perforation rate was 78 out of 950 gloves (8.2%), and 42 out of 109 operations (22%). Glove perforation rate was 5.1% in Double-gloves and 3.5% in Triple-gloves. Conclusion: Patients with diabetes, Rheumatoid arthritis, older age, BMI of >30 kg/m2 had increased PJI risk. Additional systematic large-scale studies are needed to verify these results.

Septic arthritis is an orthopaedic emergency. Despite advances in medical knowledge and treatment options, the morbidity remains as high as 30-35%, with a mortality of up to 10% over the last 5 decades. The objectives of this study were to investigate the risk factors associated with secondary surgery for septic arthritis of the native knee joint as well as its clinical and microbiological characteristics in the population. This is a retrospective study reviewing all patients who underwent surgery for septic arthritis of the native knee from Jan 2012 to Jun 2019 in a single institution. A total of 117 patients underwent surgery for knee septic arthritis between Jan 2012 to Jun 2019. There were 79 patients (67.5%) who underwent one surgical treatment for knee septic arthritis and 38 patients (32.5%) underwent more than 1 surgery. Patients with diabetes mellitus had increased risk of secondary operation whereas conditions such as End-Stage Renal Failure (ESRF) and Ischemic Heart Disease (IHD) trended towards significance. Patients with raised initial total white cell count of >20 x 109/L has an adjusted hazard ratio of 2.42 on the risk for secondary surgery and decline of CRP level of less than 20% within 24 hours from initial operation has an adjusted hazard ratio was 0.34. Both results were statistically significant. In our study, 78 (84.8%) of patients with positive bacterial growth in joint culture had gram positive infections and the top 3 microbes were Methicillin Susceptible Staphylococcus Aureus (MSSA), Group B Streptococcus (GBS) and Streptococcus Dysgalactiae.

Tumoral calcinosis is a rare entity whose etiology and pathophysiology are not fully understood, but most likely result from an imbalance of phospho-calcium metabolism, leading to the deposition of calcium crystals in the peri-articular tissues. It is more common in females, aged 10-13 years. It is mainly located in the hip and shoulder and rarely in the knee. Surgical treatment is indicated in symptomatic cases. Clinical case of prepatellar tumoral calcinosis, documented with patient images and perioperative radiological study. A 13-year-old female patient, referred to the orthopedics consultation because of pain at the front of the left knee, with one year of evolution. At the objective examination, she had several tumefactions, infracentimetric, nacreous and distributed throughout the prepatellar region. Radiologically: multiple calcifications located in the prepatellar bursa. Study of phospho-calcium metabolism revealed no change. She was submitted to bursectomy and excision of calcifications. Histological examination confirmed the diagnosis of tumoral calcinosis. Post-operatively, scar improved favorably, and the return to unrestricted activity was at 4th week after surgery. At 12 months of follow-up, the patient is asymptomatic, without associated cutaneous lesions and without limitation of the left knee range of motion. Radiologically, traces of some vestigial calcifications are visible. The typical lesions of calcinosis are lobulated and well defined, located on the extensor surface of the joint. Their correct identification is crucial since it makes a differential diagnosis with synovial osteochondromatosis, synovial sarcoma and ossifying myositis.

Introduction: Stiffness following total knee replacement (TKR) is a disabling complication that may require manipulation under anaesthesia (MUA). During the COVID-19 pandemic virtual physiotherapy services were introduced and largely replaced in person review. There is little evidence available to assess the efficacy of this service especially for the older population who are typical candidates for TKR. This study aims to review if the rate of MUA following any major knee surgery, including trauma, increased during the pandemic. Methods: This was a single centre, retrospective cohort study comparing an 11-month period during the COVID-19 pandemic with the same time frame in 2019. Trauma and elective lists were reviewed for all major knee surgery typically associated with potential post-operative stiffness. This included primary and revision TKR, trochleoplasty, tendon repair, patella tension band wire and open reduction internal fixation of fractures. The rate of subsequent MUA was calculated for procedures performed. Results: Rate of MUA following all major knee surgery significantly increased from 2.2% to 6.8% (p=0.0357) during the COVID-19 pandemic with the introduction of virtual physiotherapy. Prior to the pandemic, MUAs were exclusively for stiffness post TKR. During the pandemic MUA for stiffness following trauma surgery was newly observed. There was no difference in median time to the first surgical post-operative review. Conclusion: Virtual physiotherapy is not effective following major knee surgery and has resulted in significantly higher rates of subsequent MUA. Every effort should be made to resume in person physiotherapy reviews.