Introduction: Total hip arthroplasty preformed with the use of minimal incision surgery has received tremendous attention recently. Various surgical approaches have been introduced to minimize surgical trauma to the soft tissues. The mini invasive Modified Watson-Jones approach have been selected to decrease the perioperative complications associated with other mini invasive approaches that has been described.

The anterolateral mini incision is a new innovative approach using the intramuscular plan between the gluteus medius and the tensor fascia lata. This intermuscular interval through a small incision provides good exposure and preserves muscle integrity. Moreover, preserving the muscle integrity provides a very stable joint after implantation such that no restrictions is giving to the patient during the rehabilitation period.

Materials and Methods: Between July 2004 to September 2005, we used this approach on 60 sequential patients. Fifty patients were enrolled in this prospective study. Patients were evaluated preoperatively, immediately postoperatively, and at 3-month and 6 month follow-up according to operating time, intraoperative blood loss, subcutaneous drains blood loss, post op pain control drugs requirements, short form 36 patient questionnaire (SF-36) scores and the Harris Hip Score (HHS). 4 patients had previous THA on the contralteral side.

Results: The average operation time was 137min (range 90–200min), there were no dislocations, the mean post operation blood transfusion requirements was 1.64, the mean subcutaneous drains blood loss was 241.9ml (range 20–620ml), there was significant improvement in function, pain, SF-36 and Harris Hip Score (HHS) at the 3-month and 6-month follow-up examination. The average length of the incision was under 12cm. We had one reoperation due to deep infection. All four patients with bilateral THA preferred their last operation due to lack of post operative restrictions and due to shorter recovery of muscle strength.

Conclusion: We think that using mini invasive Modified Watson-Jones approach in total hip replacement surgeries is a preferable option. There are several advantages of using this approach compared with the more traditional techniques. Such a technique should help reduce morbidity and complication rates for those patients undergoing a total hip replacement.

Increasing incidence of osteoporosis, obesity and an aging population have led to an increase in low energy hip fractures in the elderly. Perceived lower blood loss and lower surgical time, media coverage of minimal invasive surgery and patient expectations unsurprisingly have led to a trend towards intramedullary devices for fixation of extracapsular hip fractures. This is contrary to the Cochrane review of random controlled trials of intramedullary vs extramedullary implants which continues recommends the use of a sliding hip screw (SHS) over other devices. Furthermore, despite published literature of minimally invasive surgery (MIS) of SHS citing benefits such as reduced soft tissue trauma, smaller scar, faster recovery, reduced blood loss, reduced analgesia needs; the uptake of these approaches has been poor. We describe a novel technique one which remains minimally invasive, that not only has a simple learning curve but easily reproducible results. All patients who underwent MIS SHS fixation of extracapsular fractures were included in this study. Technique is shown in Figure 1. We collated data on all intertrochanteric hip fractures that were treated by a single surgeon series during period Jan 2014 to July 2015. Data was collected from electronic patient records and radiographs from Picture Archiving and Communication System (PACS). Surgical time, fluoroscopy time, blood loss, surgical incision length, post-operative transfusion, Tip Apex Distance (TAD) were analyzed. There were 10 patients in this study. All fractures were Orthopaedic Trauma Association (OTA) type A1 or A2. Median surgical time was 36 minutes (25–54). Mean fluoroscopy time was similar to standard incision sliding hip screw fixation. Blood loss estimation with MIS SHS can be undertaken safely and expeditiously for extracapsular hip fractures

Introduction. Recent advances in minimally invasive surgery and improved post-operative pain management make it possible to perform major foot/ankle operations as day-case. This could have significant impact on length of stay, saving resources and is in keeping with government policy. However, there are theoretical concerns about complications and low patient satisfaction due to pain. Methods. The survey was developed following review of the literature and was approved for distribution by the BOFAS (British Orthopaedic Foot & Ankle Society) scientific committee. An online survey (19 questions) was sent to UK foot and ankle surgeons via the BOFAS membership list. Major foot/ ankle procedures were defined as surgery that is usually performed as an inpatient in majority of centres and day-case as same day discharge, with day surgery as the intended pathway. Results. A total of 132 surgeons responded, 80% from Acute NHS Trusts. The majority (78%) thought that more procedures could be performed as day-case at their centre. Currently 45% of respondents perform less than 100 day-case surgeries per year for these procedures. Despite post-operative pain and patient satisfaction being theoretical concerns for day-case surgery in this population; these outcomes were only measured by 34% and 10% of respondents respectively. The top perceived barriers to performing more major foot and ankle procedures as day-case were: Lack of physiotherapy input pre/post-operatively (23%), Lack of out of hours support (21%). Conclusions. There is consensus among surgeons to do more major foot/ ankle procedures as day-case. Despite theoretical concerns about post-operative pain and satisfaction this was only measured by a third of those surveyed. Out of hours support and physiotherapy input pre/ post-op were perceived as the main barriers. There is a need to scope the provision of physiotherapy pre/post-operatively and out of hours support at sites where this is a perceived barrier

Background. Optimal management of displaced intra-articular calcaneal fractures remains controversial. The aim of this prospective cohort study was to compare the clinical and radiological outcomes of minimally invasive surgery (MIS) versus non-operative treatment in displaced intra-articular calcaneal fracture up to 2-years. Methods. All displaced intra-articular calcaneal fractures between August 2014 and January 2019 that presented to a level 1 trauma centre were considered for inclusion. The decision to treat was made by a multidisciplinary meeting. Operative treatment protocol involved sinus tarsi approach or percutaneous reduction & internal fixation. Non-operative protocol involved symptomatic management with no attempt at closed reduction. All fractures were classified, and the MOXFQ/EQ-5D-5L scores were used to assess foot and ankle and general health-related quality of life outcomes respectively. Results. 101 patients were recruited at a level 1 major trauma centre, between August 2014 and January 2019. Our propensity score matched 44 patients in the surgical cohort to 44 patients in the non-surgical cohort. At 24 months, there was no significant difference in the MOXFQ Index score (p<0.05) however the patients in the surgical cohort had a significantly higher EQ-5D-5L Index score (p<0.05). There was also a higher return to work (91% vs 72%, p<0.05) and physical activity rate (46 vs. 35%, p<0.05) in the surgical cohort despite a higher proportion of more complex fractures in the surgical cohort. The wound complication rate following surgery was 16%. 14% of patients in the non-operative cohort subsequently underwent arthrodesis compared to none of the patients in the surgical cohort. Conclusion. In this study, we found operative treatments were associated with low rates of surgical complication at 2-years and long term pain improvement, facilitating earlier and better functional outcomes for complex injury patterns compared to nonoperative treatment

Currently, fibrin glue obtained from fibrinogen and thrombin of human and animal blood are widely investigated to use as injectable hydrogel for tissue engineering which contributes to minimally invasive surgery, superior biodegradability, cell attachment, proliferation and regenerating new tissue. However, most of them fail to achieve to be used for tissue engineering application because of a risk of immune response and poor mechanical properties. To overcome the limitation of fibrin glue and to reduce the usage of products from human and animal blood, the artificial fibrin glue materials were developed. Recently, cellulose nanofiber (CNF) as reinforcing agent has been explored for many tissue engineering applications such as bone and cartilage due to its impressive biological compatibility, biodegradability and mechanical properties. CNF was extracted from cassava pulp. PEO-PPO-PEO diacrylate block copolymer is a biodegradable synthetic polymers which is water insoluble hydrogel after curing by UV light at low intensity. To enhance the cell adhesion abilities, gelatin methacrylate (GelMA), the denature form of collagen was used to incorporate into hydrogel. The aim of this study was to develop the artificial fibrin glue from CNF reinforced PEO-PPO-PEO diacrylate block copolymer/GelMA injectable hydrogel. CNF/PEO-PPO-PEO diacrylate block copolymer/GelMA injectable hydrogels were prepared with 2-hydroxy-1-(4-(hydroxy ethoxy) phenyl)-2-methyl-1-propanone (Irgacure 2959) as a photoinitiator. The physicochemical properties were investigated by measuring various properties such as thickness, gel fraction, mechanical properties and water uptake. At optimal preparation condition, CNF reinforced injectable hydrogel was successful prepared after curing with UV light within 7 minutes. This hydrogel showed gel fraction and water uptake of 81 and 85%, respectively. The cytotoxicity, cell adhesion and proliferation of CNF reinforced injectable hydrogel was presented. Cellulose nanofiber from casava pulp was successfully used to prepare injectable hydrogel as artificial fibrin glue for tissue engineering. The hydrogel showed good physical properties which can be applied to use for tissue engineering application

Lateral approach open calcaneal osteotomy is the described gold standard procedure in the management of hindfoot deformity. With development of minimally invasive surgery, a MIS approach has been described, citing fewer wound complications and lower risk of sural nerve injury. This audit compares MIS to the traditional procedure. A retrospective review of all patients undergoing calcaneal osteotomy in Northumbria Trust in the past 5 years was performed. A total of 105 osteotomies were performed in 97 patients; 28 (13M:15F) in MIS group and 77 (40M:37F) had an open approach. The average age was 52.1 (range 16–83) for MIS and 51.5 (range 18–83) in the open group. All patients were followed up for development of wound complication, nerve injury and fusion rate. Wound complications were similar (10.7% in MIS group vs 10.3% in Open group) with no significant difference (p=0.48). Patients were treated for infection in 3(3.8%) cases in the open group and 2(7.1%) in the MIS group. This difference was not significant (p=0.43). 4 (14.3%) patients in the MIS group had evidence of sural nerve dysfunction post-operatively (managed expectantly), compared to 12(15.5%) patients in the open group (p=0.44). Of these, 2 went on to undergo neuroma exploration. There was no difference in nerve dysfunction in varus or valgus correction. Mean translation in the open group was measured as 7.3mm(SD=1.91;3 to 13mm) and 7.5mm(SD=1.25;5 to 10mm) in the MIS group. Translation was similar in varus or valgus correction. Non-union occurred in 2 patients in the MIS group and none in the open group (p= 0.06). MIS calcaneal osteotomy is a safe technique, that works as effectively as osteotomy performed through an open approach. There were lower rates of nerve injury, wound complication and infection, but this was not significantly different comparing groups. There was a higher risk of non-union in MIS technique

Introduction and Objectives: During the last few years there has been a trend towards minimally invasive total knee replacement (TKR). The advantages described for minimally invasive surgery (MIS) are diverse; however, some disadvantages have also been described such as the difficulty of adequately calculating the dimensions of the components. Assessment of the tendency to use an undersized femoral component in MIS. Materials and Methods: We studied two multi-center cohorts (Grupo Scorpio España and Grupo Scorpio-MIS España) of patients in whom the same model of prosthesis was implanted surgically, in one group using conventional techniques and in the other using minimally invasive surgery. Using conventional techniques, 371prostheses were implanted in 14 centers, and using MIS, 130 prostheses were implanted in 10 hospitals. The tibial component is easier to measure and has been used as a reference. We assessed the differences between femur and tibia size in both groups of patients, the conventional surgery group and the minimally invasive surgery group. Results: Using this model of prosthesis, in the conventional group, 45% of the femur components were a size larger than the tibial components, whereas this was seen in 30% of the MIS group (p=0.001956). A smaller size femur component was implanted in the same percentage of cases in both groups (6%). No differences were seen based on the group body mass index. Discussion and Conclusions: With the data from this multicentric study, in which the same model of prosthesis was used, we confirmed, by means of a significant difference, that there is a tendency to use an undersized femoral component in MIS in comparison with conventional surgery procedures

Introduction and Objective. Lower limb fractures are amongst the most common surgically managed orthopaedic injuries, with open reduction and internal fixation (ORIF) as the conventional method of treatment of the fibula. In recent years, dedicated intramedullary implants have emerged for fibula fixation in tandem with the move towards minimally invasive surgery in high-risk patients. This is the largest multicentre review to date with the aim of establishing the clinical outcomes following intramedullary nail (IMN) fixation of the fibula and to identify the absolute indication for fibula IMN fixation. Materials and Methods. A retrospective study of adult patients in all UK hospitals, who underwent fibula nail fixation between 01/01/2018 and 31/10/2020 was performed. Primary outcome measures included time to union, infection rate, other post-operative complications associated with the fixation and length of hospital stay. The secondary outcome measure was to identify the indication for fibula nailing. Data tabulation was performed using Microsoft Excel and analysis was performed using SPSS Version 23 (SPSS Statistics). Results. 2 Major Trauma Centres (MTCs) and 9 Trauma Units (TUs) were eligible for inclusion. 102 patients were included and 91% were classified as ankle fractures of 68% (n=69) were Weber B, 24% (n=24) Weber C and 8% (n=9) were either distal tibial fractures with an associated fibula fracture or pilon fractures. The mean age was 64 years of which 45 were male patients and 57 were female. The average BMI was 30.03kg/m. 2. and 44% of patients were ASA 3. 74% of patients had poor pre-op skin condition including swelling and open wounds. The calculated infection rate for fibula nail was 4.9% and metal-work complication rate was 4.9%. The average time to union was 13 weeks and length of inpatient stay was 15 days (SD +/− 12 days). Conclusions. MEFNO has demonstrated that fibula nail is an ideal implant in patients who have a physiologically higher risk of surgery, poor skin condition and a complex fracture pattern. The time to union, complication and infection risks are lower than that reported in literature for ankle ORIFs

Background:. Previous attempts at small incision hallux valgus surgery have compromised the principles of bunion correction in order to minimise the incision. The Minimally Invasive Chevron/Akin (MICA) is a technique that enables an open modified Chevron/Akin to be done through a 3 mm incision, facilitated by a 2 mm Shannon burr. Methodology:. This is a consecutive case series performed between 2009 and 2012. This includes the learning curve for minimally invasive surgery. All cases were performed by a single surgeon at two different sites, one centre where minimally invasive surgery is available and the other where it is not. The standard procedure in both centres is a modified Chevron osteotomy. Regardless of whether the osteotomy was performed open or minimally invasive two-screw fixation was performed. Retrospective analysis includes the IMA, HVA, M1 length, forefoot width and forefoot: hindfoot ratio. Clinical outcomes include the MOXFQ, AOFAS, and assessment of complications. Results:. There were 70 cases in each arm. Follow-up was 4 years to 6 months. The radiological outcomes were similar in both groups. There was an increased rate of screw removal in the MICA group. There were also cases of hallux varus, these occurred in the cases with severe pre-operative IMA angles that also had a lateral release and an Akin. There was high satisfaction in both groups. Conclusion:. This is the only comparison of minimally invasive and open techniques that has been performed, providing a direct comparison of the utility of a burr compared to a saw. These early results demonstrate the efficacy of a Minimally Invasive Chevron/Akin in terms of achieving radiological correction. The clinical outcomes are excellent but there is a learning curve and this needs to be managed

Background. Recent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiological outcomes. It remains unknown whether these clinical and radiological outcomes are maintained in the medium to long-term. The aim of this study was to investigate the five-year clinical and radiological outcomes following third-generation MIS hallux valgus surgery. Methods. A retrospective observational single surgeon case series of consecutive patients undergoing primary isolated third-generation percutaneous Chevron and Akin osteotomies (PECA) for hallux valgus with a minimum 60 month clinical and radiographic follow up. Primary outcome was radiographic assessment of the hallux valgus angle (HVA) and intermetatarsal angle (IMA) pre-operatively, 6 months and ≥60 months following PECA. Secondary outcomes included the Manchester-Oxford Foot Questionnaire, patient satisfaction, Euroqol-5D Visual Analogue Scale and Visual Analogue Scale for Pain. Results. Between 2012 and 2014, 126 consecutive feet underwent isolated third-generation PECA. The mean follow up was 68.8±7.3 (range 60–88) months. There was a significant improvement in radiographic deformity correction; IMA improved from 13.0±3.0 to 6.0±2.6, (p < 0.001) and HVA improved from 27.5±7.6 to 7.8±5.1. There was a statistically significant but not clinically relevant increase of 1.2±2.6° in the HVA between 6 month and ≥60 month radiographs. There was an increase in IMA of 0.1±1.6º between 6 month and ≥60 month radiographs which was not statistically or clinically significant. MOXFQ Index score at ≥follow up was 10.1±17.0. The radiographic recurrence rate was 2.6% at final follow up. The screw removal rate was 4.0%. Conclusion. Radiological deformity correction following third-generation PECA is maintained at a mean follow up of 68.8 months with a radiographic recurrence rate of 2.6%. Clinical PROMs and patient satisfaction levels are high and comparable to other third-generation studies with shorter duration of follow up

Implant removal is necessary in up to 25% of patients with plate osteosynthesis after proximal humeral fracture. Our new technique of arthroscopic implant removal offers all advantages of minimal invasive surgery. Additionally treatment of concomitant intraarticular lesions is possible. This study outlines the first results after arthroscopic implant removal in comparison with those of open implant removal. A prospective series of 40 consecutive treated patients had implant removal and arthrolysis after plate osteosynthesis of proximal humeral fracture. Implant removal was carried out due to limitation in range of movement, secondary implant dislocation and implant impingement. 30 patients (median age 63 (30–82) years) had arthroscopic, ten patients (median age 53 (34–76) years) had open implant removal. Median 10 months after implant removal subjective patient satisfaction, Constant Murley Score (CMS) and Simple Shoulder Test were determined. Arthroscopic implant removal showed comparable first results as open implant removal. There was no significant difference between CMS of both groups. The active shoulder abduction, flexion and external rotation improved significantly after arthroscopic and open implant removal. The simple shoulder test outlined advantages for the arthroscopic technique. After arthroscopic implant removal patients showed higher subjective satisfaction as well as faster pain reduction and mobilization. Analysis of perioperative data showed less blood loss in the group with arthroscopic implant removal. In 85% of patients with arthroscopic implant removal concomitant intraarticular lesions were observed and treated. The arthroscopic implant removal after plate osteosynthesis of proximal humeral fractures offers all advantages of minimal invasive surgery and comparable first results as the open implant removal. The subjective and objective satisfaction of patients is high. The technique can be applied and established by all arthroscopic trained shoulder surgeons

Background. Minimally invasive surgery is being widely used in the field of total hip arthroplasty (THA). The advantages of the direct anterior approach (DAA), which is used in minimally invasive surgery, include low dislocation rate, quick recovery with less pain, and accuracy of prosthesis placement. However, minimally invasive surgery can result in more complications related to the learning curve. The aim of this study was to evaluate the learning curve of DAA-THA performed by a senior resident. Methods. Thirty-three consecutive patients (33 hips) who underwent primary THA were enrolled in this study. All operations were performed by a senior resident using DAA in the supine position without the traction table. The surgeon started using DAA exclusively for all cases of primary THA after being trained in this approach for 6 months. Operative time, intraoperative blood loss, complications, and accuracy of prosthesis placement were investigated. Results. The mean intraoperative blood loss was 524 mL (range, 130–1650 m L). The mean operative time was 60 min (range, 41–80 min). Radiographic analysis showed an average acetabular anteversion angle of 17.0±3.3°, abduction angle of 37.8±4.3°, and stem alignment of 0±0.8°. Thirty-two (97%) of 33 cups were placed within the Lewinnek's safe zone. The overall complication rate was 12% (4 of 33 hips), including 1 proximal femoral fracture (salvaged with circumferential wiring), 1 temporary femoral nerve palsy (completely recovered in 2 weeks), 1 stem subsidence (5 mm), and 1 cup migration. Three of these complications were occurred in the first 10 cases. No revision surgery was required, No postoperative dislocation occurred. Conclusion. We investigated the learning curve of DAA-THA performed by a senior resident. We considered the first 10 cases as the learning curve, but concluded that with adequate training this procedure can be performed safely and effectively without increasing the risk of complications

Navigation technology is a new tool which can help surgeons to a more accurate hip component implantation and a better reproducibility of the procedure. The purpose of this study was to compare conventional and navigated technique and a new developed straight hip stem for uncemented primary total hip replacement. The results of two consecutive implantation series of 42 patients (non navigated) and 42 patients (navigated) were analysed for implant positioning and short term complications. Non navigated components were implanted through conventional incision (15 cm), navigated component by minimal invasive surgery (5 cm). All surgeries were performed through Hardinge approach and by a single senior surgeon. Radiographic analysis of cup position showed a significant improvement with reduced radiological inclination (53° non navigated/44° navigated, p< 0.001) and higher anteversion (7° non navigated/12° navigated, p< 0.001). The mean postoperative limb length difference was 6.2 mm (SD 9.0, non navigated) and 4.4 mm (SD 6.4, navigated). Intraoperative and early postoperative complications were not different. No dislocation occurred in both groups. There was one intraoperative trochanter fracture which was not revised (non navigated) and one revision because of a periprosthetic fracture caused by fall down during rehabilitation (navigated). We conclude that acetabular implant positioning can be significantly improved by the use of navigated surgery technique even in minimal invasive surgery condition. The data for postoperative limb length difference was still similar but within the expected range in both groups. Navigation technology seems essential for minimal invasive surgical procedure yielding help and security to the surgeon. The effect of improved cup positioning on mid and long term results for both groups have to be further investigated

Introduction We believe minimally invasive surgery should be defined by the extent of soft tissue dissection rather than incision length. We describe a new technique that is truly soft-tissue sparing and report our early results. The surgical approach The landmarks for the incision are identified and an incision is made over the posterior aspect of the greater trochanter. Piriformis is preserved. A capsular repair is performed through drill holes into bone. There are no restrictions to mobility. No specialised instruments are required. Method The standard posterior approach (group 1) was compared with the PSMI approach (group 2) in a prospective cohort study of 200 consecutive patients over 60 years of age. Patients were scored pre-operatively and followed up prospectively, by a blinded observer. Results Mean operation time was about 1 hour in both groups. Mean incision length was 21.5 cm in group 1 and 8.4cm in group 2. Mean blood loss in group 1 was significantly higher than group 2 (P< 0.0001). Mean inpatient stay was significantly higher in group 2 (P< 0.0001). Minimum follow-up was 3 years in group 1 and 1.5 years in group 2. There were 3 dislocations in group 1, and none in group 2. There were 2 re-operations in both groups. The relative improvement in WOMAC scores was significantly greater in group 2 at 3 months and 1 year (P< 0.05). Conclusion: This is the first study to suggest the benefits of minimally invasive surgery may be prolonged. Cosmesis is a by-product rather than primary objective

Today minimally invasive surgery inspires orthopaedic surgeons to consider techniques that minimize morbidity and produce equal or better outcomes. Minimally invasive surgery–total knee arthroplasty (MIS-TKA) approach involves a medial para-patellar incision which leads to a smaller skin incision, limited soft tissue dissection and sparing of the Quadriceps muscle. This prospective and retrospective study was carried out at Dayanand Medical College and Hospital, Ludhiana (India) from January 2007 to June 2010 to evaluate forty nine patients with unilateral and six patients of Bilateral MIS-TKA. Patients with osteoarthritis and rheumatoid arthritis undergoing primary TKA using cemented modular posteriorly stabilized prosthesis were included in the study. All the procedures were performed through anterior midline incision measuring 8.5–10 cms (mean 9.2 cms). Extent of the incision into the quadriceps tendon was limited to the level of superior pole of patella and vastus medialis muscle was not split. Patella was not everted but retracted laterally. Four in One Nexgen legacy, minimal invasive surgery instrumentation was used. Aggressive physiotherapy was started on the first postoperative day with knee bending and walking on day two. The patients were evaluated according to knee society knee score and function score at one, three and six months and again at one year postoperatively. Mean final knee score improved from 30 to 91 (p-value = .00001). Mean functional score improved from 25 to 78 (p-value = .00001). Mean stability score improved from 19.46 to 22.98 points postoperatively. Patients with lesser preoperative flexion contracture had better outcomes and preoperative range of motion predicted final range of motion. Mean ROM improved from preoperative value of 85 to 101 at discharge, 114 at 12 weeks and 120 at 6 months (p-value = .0007, .0006, .0009 respectively). 79.1% patients were completely pain-free on the final follow-up. Mean tourniquet time was 65 minutes (55–75). 91.4% patients suffered <300 ml blood loss in drains. One patient each of patellar maltracking and deep infection was seen in our study. We concluded that MIS-TKA with quadriceps sparing approach in our patients lead to a limited arthrotomy, decreased blood loss, less blood transfusion requirements, less postoperative pain, faster recovery of motion and return of function. This study proposes that MIS-TKR has many advantages over the conventional procedure and these are mainly attributed to the sparing of quadriceps muscle

Introduction. Injectable hydrogels via minimally invasive surgery offer benefits to the healthcare system, reduced risk of infection, scar formation and the cost of treatment. Development of new treatments with the use of novel biomaterials requires significant pre-clinical testing and must comply with regulations before they can reach the bedside. In the European economic area (EEA) one of the first hurdles of this process is attaining the CE marking which protects the health, safety and environmental aspects of a product. Implanted materials fall under the class III medical device EU745 regulation standards. To attain the CE marking for a product parties must provide evidence of the materials safety with an investigational medicinal product dossier (IMPD). Methods and Results. We have been working to develop a new thermoresponsive injectable biomaterial hydrogel (NPgel) for the treatment of intervertebral disc (IVD) disease. A large part of the IMPD requires information on how the hydrogel physical properties change over time in bodily conditions. We have been studying 6 batches of NPgel over 18 months, tracking the materials wet/ dry weight, structure and composition. To date we have found that NPgel in liquids more similar to the body (with protein and salts) appear to be stable and safe, whilst those in distilled water swell and disintegrate over time. Subtle long-term changes to the material composition were found and we are currently investigating its ramifications. Conclusion. The study highlights the need to test materials in detail in physiologically representative environments before approaching the bedside and demonstrates promise for NPgel as a suitable CE candidate. Conflicts of interest: CS and CLM are named inventors on the patent for NPgel/BGel. Funded by the Medical Research Council and Versus Arthritis UK: SNiPER

Introduction Unicompartmental knee arthroplasty (UKA) is well established in the treatment of OA of the knee, but has not been performed in large numbers compared with total knee arthroplasty. However, with the development of minimally invasive surgery, numbers of procedures are increasing rapidly. This study examines the results of minimally invasive UKA performed by one surgeon since august 1998. Methods A consecutive series of 388 knees in 360 patients operated between August 1988 and February 2003 were evaluated using a prospective database. All surgeries were performed by the senior author using a minimally invasive technique in a day surgery unit. General anaesthesia was used in all cases with local anaesthesia intra-operatively, combined with an anaesthetic infusion pump. No patient received parenteral narcotics. Ninety-seven percent were medial and three percent were lateral arthroplasties. Results Post-operatively no patients were lost to follow-up which ranged from two months to 4.5 years. Average age was 66 years. The average IKS score improved from 75 to 158 post-operatively. Most patients retained their pre-operative range of motion which averaged 120°. Average length of stay was 1.57 days with 41% of patients discharged the same day. There were five failures, due in part to osteoporosis and overcorretion. These were revised successfully to a ‘primary’ type knee prosthesis. Satisfaction rate subjectively was 98%. Conclusions Mid term results of UKA using the Repicci technique of minimally invasive surgery with rapid mobilisation and early discharge has ahcieved excellent results for unicompartmental OA of the knee. The procedure is better tolerated with a low complication rate and higher patient satisfaction than total knee replacement in this gourp of patients

Introduction: The aim of the study is to evaluate different operation techniques after total knee arthroplasty (TKA). Functional outcome as well as objective results in activity (activity monitor) after minimal invasive TKA was compared with functional outcomes after a standard midvastus approach. Purpose: The primary purpose of the present study was to determine the difference between two approaches in surgery of total knee arthroplasty. Is there a difference in outcome between a standard and a minimal invasive surgery because of less muscle damage and soft tissue stress?. Material and methods: The study includes two groups with 20 patients each (MIS group versus standard group) The patients are investigated at six different times: 1 day preoperatively as well as on 1., 3., 7. day postoperatively as well as 6 and 12 weeks after surgery. We used the AMP 331 (Dynastream Innovations, Inc., Cochrane, AB) a new ankle-mounted activity monitor. Step count, distance travelled, walking speed, step length, cadence and energy expenditure were measured. 1, 6 and 12 weeks postoperatively patients got the device for 5 days. Results: The average age in the standard group was 66.4 years and for the MIS group, 66,8. The MIS group has been shown a sig. higher KSS Score versus standard group in all follow up visits. Standard group has shown a slight higher blood loss and higher values of muscle specific lab parameter (Creatininkinase and Myoglobin). The Activity Score was better in the MIS group in comparison to the standard group. These results also mirrored the data from the activity monitor (AMP 331, Dynastream Innovations, Inc., Cochrane, AB). The average walking speed at 1, 6 and 12 weeks was sig. (p< 0.05) better than in the standard group. Same trend we have seen in cadence, step length and steps per day. Conclusion: This study shows that patient who underwent minimal invasive surgery in knee arthroplasty have an better early outcome after surgery in activity and function because of saving muscle structure and minimise soft tissue stress

The treatment of fractures has evolved from extensive open reduction and internal fixation to minimally invasive surgery and biological fixation. High energy bicondylar tibial plateau fractures pose a treatment challenge to most orthopaedic Surgeons. This study evaluates the results of biologic plating of bicondylar tibial plateau fractures. Between January 2005 and January 2006 we treated 25 closed bicondylar tibial plateau fractures with minimally invasive surgery using locking plates and screws. Routine tomograms and CT scans were performed after a detailed history and physical examination were performed. Pre-operative planning and templating was performed in all cases. Surgery was carried out by the same surgical team using a tourniquet and an anterolateral or medial surgical approach. Bone grafting was also performed in some cases. The implants used were pre-contoured locking plates (Synthes, Smith & Nephew). The rehabilitative programme was commenced on day 2 by the same Physiotherapist and non weight bearing for 12 weeks. Four patients refused to be part of the study and two were lost to follow up. Nineteen patients were available for follow up with a mean follow up of 10 months. There were 10 males with mean age of 35 years. Two patients were treated for early superficial wound sepsis which healed. Eight patients needed a bone graft at the time of surgery. The average range of movement was 5–110 degrees of flexion. There were no implant failures or non unions. At six months all patients walked unaided with no deformity and were satisfied with the operation. As an alternative to external fixation of these difficult fractures we recommend a less invasive precontoured plate with locking screws. The advantages include sub-muscular, extraperiostal plate application through a relatively small incision, percutaneous screw placement through a guide, the fixed angle of the plate obviating the necessity of medial plate fixation, and plate lengths are available to span the metadiaphysis. The results suggest that biologic plating with a precontoured locking plate of bicondylar tibial plateau fractures may give better short term results with excellent function

Introduction. Injectable hydrogels via minimally invasive surgery reduce the risk of infection, scar formation and the cost of treatment. Degradation of the intervertebral disc (IVD) currently has no preventative treatment. An injectable hydrogel material could restore disc height, reinforce local mechanical properties, and promote tissue regeneration. We present a hydrogel material Laponite. ®. associated poly(N-isopropylacrylamide)-co-poly(dimethylacrylamide) (NPGel). Understanding how the components of this hydrogel system influence material properties, is crucial for tailoring treatment strategies for the IVD and other tissues. Methods & Results. The effect of hydrogel wt./wt., clay and co-monomer percentages were assessed using a box-Behnken design. Rheometry, SEM, FTIR and swelling was used to measure changes in material properties in simulated physiological conditions. Rheometry revealed gelation temperature of hydrogel materials could be modified with dimethyl-acrylamide co-monomer; however, final maximum mechanical properties remained unaffected. Increasing the weight % and clay % increased resultant mechanical properties from ∼500–2500 G' (Pa), increased viscosity, but retained the ability to flow through a 26G needle at 39°C. Discussion & Conclusions. By increasing the weight and clay percentage of the material we can attain greater mechanical properties, this could be beneficial for orthopaedic or even dental applications. By modifying the co-monomer percentage, we can control gelation temperature important for ensuring the material is fully set at 37°C, this could also be utilised to locally deliver drugs from the implanted material. Our current work is focused on comparing our NPGel material formulation with human IVD tissue. Acknowledgements. We would like to thank Arthritis Research UK grant number 21497 for supporting this research. No conflicts of interest. Sources of Funding: Funded by Arthritis Research UK grant number 21497