Aims. To report the development of the technique for minimally invasive lumbar decompression using robotic-assisted navigation. Methods. Robotic planning software was used to map out bone removal for a laminar decompression after registration of CT scan images of one cadaveric specimen. A specialized acorn-shaped bone removal robotic drill was used to complete a robotic lumbar laminectomy. Post-procedure advanced imaging was obtained to compare actual bony decompression to the surgical plan. After confirming accuracy of the technique, a minimally invasive robotic-assisted laminectomy was performed on one 72-year-old female patient with lumbar spinal stenosis. Postoperative advanced imaging was obtained to confirm the decompression. Results. A workflow for robotic-assisted lumbar laminectomy was successfully developed in a human cadaveric specimen, as excellent decompression was confirmed by postoperative CT imaging. Subsequently, the workflow was applied clinically in a patient with severe spinal stenosis. Excellent decompression was achieved intraoperatively and preservation of the dorsal midline structures was confirmed on postoperative MRI. The patient experienced improvement in symptoms postoperatively and was discharged within 24 hours. Conclusion. Minimally invasive robotic-assisted lumbar decompression utilizing a specialized robotic bone removal instrument was shown to be accurate and effective both in vitro and in vivo. The robotic bone removal technique has the potential for less invasive removal of laminar bone for spinal decompression, all the while preserving the spinous process and the posterior ligamentous complex. Spinal robotic surgery has previously been limited to the insertion of screws and, more recently, cages; however, recent innovations have expanded robotic capabilities to decompression of neurological structures. Cite this article: Bone Jt Open 2024;5(9):809–817

Aims. To determine whether there is any benefit using a minimally invasive trans-sartorial approach as described by Professor Søballe compared to the ilio-femoral for peri-acetabular osteotomy. Methods. 30 consecutive patients were operated on by a single surgeon. The first 15 underwent an ilio-femoral (I-F) approach whilst the following 15 had a trans-sartorial (T-S) approach. Fixation was achieved with 3 or 4 screws. All other aspects of surgery and rehabilitation were the same. Data was collected prospectively and included operation time, intra-operative blood loss and length of stay. Acetabular correction was measured using the sourcil and centre edge angle (CEA) on pre and post-operative radiographs. Results. Both groups had acceptable radiographic corrections with CEA improving from mean 14.5 to 38.7 degrees (T-S) and 14 to 39 degrees (I-F). The sourcil angle improved from mean 17.8 to 2 degrees (T-S) and 19.5 to −1.5 (I-F). Minimally invasive surgery reduced anaesthetic time by 62 minutes. Haemoglobin loss was reduced by 1 gram/L and there was no requirement for transfusion. Hospital stay reduced by 0.8 days. There were no major adverse complications although two partial femoral neurapraxias were noted early in the series. These fully resolved. Conclusion. We have found significant benefit from changing to minimally invasive PAO. Our patients have smaller wounds, a shorter operative time, reduced bleeding and a shorter length of stay. We found no adverse effects. The time savings have also corresponded to a cost saving for our institution. We recommend this technique although recognise that it has a learning curve and should be initiated by surgeons with previous PAO experience

Introduction

Minimally invasive plate osteosynthesis (MIPO) is a relatively new surgical technique for the management of distal tibial fractures. Conventional open technique is unfavourable to the fracture biology because of excessive soft tissue stripping and can be associated with significant devastating complications.

Introduction:

There are concerns with the use of the Shannon burr in calcaneal osteotomies entered from the lateral side, with the medial structures possibly at risk when performing the osteotomy of the medial calcaneal wall. Our aims with this study were to investigate the neurovascular relationships with the calcaneal osteotomy performed using a Shannon burr.

Background:

Calcaneal osteotomy is an established technique in correcting hind foot deformity. Patients have traditionally received an open osteotomy through Atkins lateral approach. In order to reduce the rate of wound complications associated with the Atkins approach, a minimally invasive surgical (MIS) technique has been adopted since 2011. This uses a low-speed, high-torque burr to perform the same osteotomy under radiographic guidance. The results of the new MIS technique, including post-operative complication rates, are compared to the standard open approach.

We hypothesised whether MIS techniques confer any benefit when treating thoracolumbar burst fractures.

This was a prospective, non-randomised study over the past seven years comparing conservative (bracing:n=27), conventional surgery (open techniques:n=23) and MIS techniques (n=21) for stabilisation and correction of all thoracolumbar spinal fractures with kyphosis of >20⁰, using Camlok S-RAD 90 system (Stryker Spine). All patients previously had normal spines, sustained only a single level burst fracture (T12, L1 or L2) as their only injury. Age range 18–65 years.

All patients in both operatively treated groups were corrected to under 10⁰ of kyphosis, posteriorly only. All pedicle screws/rods were removed between 6 months and 1 year post surgery to remobilise the stabilised segments once the spinal fracture had healed, using the original incisions and muscle splitting/sparing techniques. Patients were assessed via Oswestry Disability Index (ODI) and work/leisure activity status 1 year post fracture.

The conservatively treated group fared worst overall, with highest length of stay, poorest return to work/activity, and with a proportion (5/27) requiring later intervention to deal with post-traumatic deformity. 19/27 returned to original occupation, at average 9 months. ODI 32%.

Conventional open techniques fared better, with length of stay 5 days, most (19/23) returning to original work/activity, and none requiring later intervention. Average return to work was at 4 months. ODI 14%.

MIS group fared best, with shorter length of stay (48 hours), all returning to original work/activity at average 2 months, and none requiring later intervention. ODI negligible.

There was no loss of correction in either operatively treated groups.

The Camlok S-RAD 90 system is a powerful tool for correction of thoracolumbar burst fractures, and maintains an excellent correction.

MIS techniques provide the best outcomes in treating this group of spinal fractures, and offer patients the best chance of restoration to pre-fracture levels of activity.

Background. There are many different procedures described for the correction of hallux valgus deformity. Minimally invasive surgery has become increasingly popular, with clinical and radiological outcomes comparable to traditional open osteotomy approaches. There is increasing interest in hallux valgus deformity correction using third-generation minimally invasive chevron akin osteotomy (MICA) technique. Objective. To assess the radiographic correction and 2 year clinical outcomes of third-generation MICA using validated outcome measures. Methods. This is a prospective single-surgeon case series of 420 consecutive feet undergoing MICA surgery between July 2014 and November 2018. Primary clinical outcome measures included the Manchester-Oxford Foot Questionnaire (MOXFQ), EQ-5D, and the Visual Analogue Pain Scale. Secondary outcome measures included radiographic parameters, and complication rates. Results. Pre-operative and 2 year post-operative patient reported outcomes were collected for 334 feet (79.5%). At minimum 2 year follow-up, the MOXFQ scores (mean ± standard deviation (SD)) had improved for each domain: pain; pre-operative 43.9±21.0 reduced to 9.1±15.6 post-operatively (p<0.001), walking and standing; pre-operative 38.2±23.6 reduced to 6.5±14.5 post-operatively (p<0.001) and social interaction; pre-operative 47.6±22.1, reduced to 6.5±13.5 post-operatively (p<0.001). At 2 year follow-up, the VAS Pain score (mean ± SD) improved from a pre-operative of 31.3±22.4 to 8.3±16.2 post-operatively (p<0.001). 1–2 intermetatarsal angle (mean ± SD) reduced from 15.4°±3.5° to 5.8°±3.1° (p<0.001) and hallux valgus angle reduced from 33.1°±10.2° to 9.0°±5.0° post-operatively (p<0.001). Conclusion. Third-generation MICA showed significant improvement in clinical outcomes at 2 year follow-up and can be successfully used for correction of a wide range of hallux valgus deformities

Introduction. Plantar heel pain, or plantar fasciopathy (PF), is a common musculoskeletal complaint, affecting 39% of lower-extremity tendinopathies in general practice. Conservative management is recommended as the first-line treatment, yet many patients continue to experience symptoms even after ten years. There is a significant lack of high-quality evidence for the effectiveness of various treatments, highlighting the need for more research. Minimally invasive surgical options, such as endoscopic plantar fascia release and radiofrequency microtenotomy, have shown promise in reducing pain and improving outcomes. This systematic review aims to evaluate the effectiveness of these minimally invasive surgical treatments compared to non-surgical options in managing PF. Method. The systematic review, registered on PROSPERO (CRD42024490498) and adhering to PRISMA guidelines, searched databases including PubMed, Embase, Cochrane, and others for studies from January 1991 to May 2024. Keywords included plantar fasciitis, plantar fasciopathy, and heel pain. Limited to human trials, the search strategy was refined with an information specialist and found no protocol duplicates. Result. The systematic review identified eight studies involving 495 patients (56.2% women, average age 46.5 years). The studies compared various treatments, including endoscopic plantar fascia release (EPF), mini-scalpel needle (MSN) treatment, ultrasound-guided pulsed radiofrequency (UG-PRF), and needle electrolysis (NE), to non-surgical interventions and corticosteroid injections (CSI). Primary outcomes focused on pain reduction, with some needle treatments showing superior results (between-group diffence). No severe adverse events were reported. Conclusion. In conclusion, plantar fasciopathy (PF) remains a prevalent and challenging condition, that can be resistant to conservative treatments. This systematic review highlights the potential of minimally invasive surgical options, such as endoscopic plantar fascia release and needle treatments, in reducing pain and improving functional outcomes. Despite some needle treatments showing superior results, the overall lack of high-quality evidence underscores the need for further research to establish the most effective management strategies for PF

Study design: Prospective study after minimally invasive anterior approach of the thoracolumbar spine in scoliosis correction. Objective: To describe the technique and first results after minimally invasive anterior approach of the thoracolumbar junction with insertion of double rod and double screw instrumentation. Summary of Background Data: Minimally invasive techniques are used at many areas of surgery nowadays. Minimally invasive surgery should have the same correction potential as with conventional approaches. Possible advantages of minimally invasive surgery are small incisions, less tissue damage, less morbidity and an improved cosmetic appearance. Methods: In this study we describe the technique and the preliminary results of minimally invasive open approach of the thoracolumbar spine with insertion of double rod and double screw instrumentation. A consecutive series of seven patients were included. All patients were female with a mean age of 16.7 years (range 10–28). The cause of thoracolumbar scoliosis was mixed. Results: The thoracolumbar curve was 59° preoperatively and 22° at six months follow up (63% correction). The unfused thoracic curve was 40° preoperatively and 29° at six months follow-up. In the sagittal plane of the fused levels Cobb angle was 61° of lordosis preoperatively and 35° of lordosis at six months follow up. Lumbar lordosis of the unfused spine was 16° preoperative and 5° at six months follow up. Thoracic kyphosis was 33° preoperatively and 24° at six months follow-up. The average time of surgery was 6.6 hours (range 5.5–7hours). The average estimated blood loss was 764ml (range 350–1200ml). Average hospital stay was 11 days (range 5–14days), and average stay at the intensive care unit was 1.7 days (range 0–3 days). One minor neurological complication with complete recovery was observed. Conclusions: Minimally invasive surgery has the advantage of less tissue damage, less morbidity and a better cosmetic appearance. With newer implants a good correction of the scoliosis can be achieved

Minimally invasive surgery for the restoration of bone tissues lost due to diseases and trauma is preferred by the health care system as the related costs are continuously increasing. Recently, efforts have been paid to optimize injectable calcium phosphate (CaP) cements which have been recognized as excellent alloplastic material for osseous augmentation because of their unique combination of osteoconductivity, biocompatibility and mouldability. The sol-gel synthesis approach appears to be the most suitable route towards performing injectable calcium phosphates. Different strategies used to prepare bioactive and osteoinductive injectable CaP are reported. CaP gels complexed with phosphoserine-tethered poly(ε-lysine) dendrons (G3-K PS) designed to interact with the ceramic phase and able to induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) is discussed. Recently, attention has been given to the modification of hydroxyapatite with Strontium (Sr) due to its dual mode of action, simultaneously increasing bone formation (stimulating osteoblast differentiation) while decreasing bone resorption (inhibiting osteoclast differentiation). The effect of systems based on strontium modified hydroxyapatite (Sr-HA) at different composition on proliferation and osteogenic differentiation of hMSC is described. One more approach is based on the use of antimicrobial injectable materials. It has been demonstrated that some imidazolium, pyridinium and quaternary ammonium ionic liquids (IL) have antimicrobial activity against some different clinically significant bacterial and fungal pathogens. Here, we report several systems based on IL at different alkyl-chain length incorporated in Hydroxyapatite (HA) through the sol-gel process to obtain an injectable material with simultaneous opposite responses toward osteoblasts and microbial proliferation

Introduction and Objective. Management of gap non-union of the tibia, the major weight bearing bone of the leg remains controversial. The different internal fixation techniques are often weighed down by relatively high complication rates that include fractures which fail to heal (non-union). Minimally invasive techniques with ring fixators and bone transport (distraction osteogenesis) have come into picture as an alternative allowing alignment and stabilization, avoiding a graduated approach. This study was focused on fractures that result in a gap non-union of > 6 cm. Ilizarov technique was employed for management of such non-unions in this case series. The Ilizarov apparatus consists of rings, rods and kirschner wires that encloses the limb as a cylinder and uses kirschner wires to create tension allowing early weight bearing and stimulating bone growth. Ilizarov technique works on the principle of distraction osteogenesis, that is, pulling apart of bone to stimulate new bone growth. Usually, 4–5 rings are used in the setup depending on fracture site and pattern for stable fixation. In this study, we demonstrate effective bone transport and formation of gap non-union more than 6 cm in 10 patients using only 3 rings construct Ilizarov apparatus. Materials and Methods. This case study was conducted at Dr. D. Y. Patil Medical Hospital, Navi Mumbai, Maharashtra, India. The study involved 10 patients with a non-union or gap > 6 cm after tibial fracture. 3 rings were used in the setup for the treatment of all the patients. Wires were passed percutaneously through the bone using a drill and the projecting ends of the wires were attached to the metal rings and tensioned to increase stability. The outcome of the study was measured using the Oxford Knee scoring system, Functional Mobility Scale, the American Foot and Ankle Score and Visual Analog Scale. Further, follow up of patients was done upto 2 years. Results. All the patients demonstrated good fixation as was assessed clinically and radiologically. 9 patients had a clinical score of > 65 which implied fair to excellent clinical rating. The patients showed good range of motion and were highly satisfied with the treatment as measured by different scoring parameters. Conclusions. In this case study, we demonstrate that the Ilizarov technique using 3 rings is equally effective in treating non-unions > 6 cm as when using 4–5 rings. Obtaining good clinical outcome and low complication rate in all 10 patients shows that this modified technique can be employed for patients with such difficulties in the future

Introduction. Charcot Arthropathy related foot and ankle deformities are a serious challenge. Surgical treatment of these deformities is now well established. The traditional surgical method of extensive surgical exposure, excision of bone, acute correction and internal fixation is not always appropriate in presence of active ulceration, deep infection and poor bone quality. Minimally invasive osteotomies and gradual correction of deformities with a circular frame are proving helpful in minimizing complications. We present our experience with the use of Taylor Spatial Frame (TSF) in 10 patients with recurrent ulceration and deformity. Materials and Methods. Our indication for the treatment with TSF is recurrent or intractable ulceration with or without active bone infection or a history of infection in a deformed foot and/or ankle. There are 2 female and 8 male patients in this cohort. We used a long bone module for ankle and hindfoot deformities (3 patients) and a forefoot 6×6 butt frame (7 patients) for midfoot deformities. An osteotomy through midfoot was performed in all chronic stable midfoot deformity cases and a calcaneal osteotomy and gradual correction through ankle in when hindfoot and ankle deformities co-existed. Results. Our outcome measures are a complete healing of ulcer and infection without recurrence, clinically plantigrade foot and ability to wear regular shoes or diabetic footwear. We achieved this outcome in 9 out of 10 patients. Successful patients remain ulcer free at minimum 7 and maximum 14 years follow up. Complications included eight episodes of pin infection that responded to oral antibiotics only and two pin breakages. Conclusions. Our results confirm that Taylor Spatial Frame treatment is a good alternative to traditional surgery in high-risk complex Charcot neuroarthropathy foot and ankle deformities

Introduction. The placement of a large interbody implant allows for a larger surface area for fusion, vis a vis, via retroperitoneal direct anterior, antero-lateral and lateral approaches. At the same time, spinal navigation facilitates a minimally invasive fixation for inserting posterior pedicle screws. We report on the first procedures in the United Kingdom performed by a single-surgeon at a single- centre using navigated robot-assisted spine surgery without the need for guide-wires. Materials and Methods. Whilst positioned in the supine or lateral position, a routine supine anterior lumbar interbody fusion (ALIF), and/or antero-lateral ALIF (AL-ALIF) and/or lateral lateral interbody fusion (LLIF) is performed. The patient is then turned prone or kept in the single lateral position (SPL) for insertion of the posterior screws performed under robotic guidance. Intraoperative CT scan 3D images captured then are sent to the Robotic software platform for planning of the screw trajectories and finally use again at the end of the procedure to confirm screw accuracy. We identified 34 consecutive patients from October 2019 to January 2020 who underwent robotic assisted spine surgery. The demographic, intraoperative, and perioperative data of all these patients were reviewed and presented. Results. Of the 34 patients, 65 levels were treated in total using 204 screws. Of the 21 patients (60%) who underwent single-level fixation, 14 of them (67%) were treated at the L5/S1 level, 3 at L3/L4, 3 at L4/L5 and 1 at L2/L3 level. The remaining 13 patients (40%) underwent multi-level fixation, of which 4 were adult scoliosis. 15 underwent a supine ALIF approach, 1 underwent AL-ALIF, 8 patients underwent combined LLIF and AL-ALIF approach in a lateral decubitus, whilst 9 underwent pure LLIF approach (of which 3 patients were in the single position lateral) and one patient had previous TLIF surgery. The average estimated blood loss was 60 cc. The average planning time was 10 min and the average duration of surgery was 50 min. The average patient age was 54 years and 64% (22/34) were male. The average BMI was 28.1 kg/m. 2. There were no re-interventions due to complications or mal positioned screws. Conclusion. Minimally invasive spine surgery using robot-assisted navigation yields an improved level of accuracy, decreased radiation exposure, minimal muscle disruption, decreased blood loss, shorter operating theatre time, length of stay, and lower complication rates. Further follow-up of the patients treated will help compare the clinical outcomes with other techniques

Minimally Invasive foot surgery remains controversial. Potential benefits include a reduced incidence of wound complications, faster return to employment and normal footwear. There are no studies published regarding the results of minimally invasive dorsal cheilectomy. Patients and Methods. Thirty eight patients with painful grade I hallux rigidus underwent dorsal cheilectomy between April 2006 and June 2010. Minimally invasive cheilectomy (MIC) was introduced in August 2009. AOFAS scores, satisfaction, return to normal shoes and employment were assessed. Results. Twenty two patients had open cheilectomy (OC) whilst 16 had MIC. Mean follow-up was 6 months for the MIC group and 35 months for the OC group. Mean AOFAS score was 75/100 (SD 17) in the MIC group and 70/100 (SD 18). Patients rated their satisfaction as 9.1/10 for MIC and 8.6/10 for OC. There was no significant difference in time to return to normal shoes (P = 0.32) or employment (P = 0.07). Two patients (one MIS, one OC) had a superficial wound infection which resolved with oral antibiotics. One patient had a first metatarsophalangeal joint fusion in the MIS group. Two patients in the OC group went on to have a first metatarsophalangeal joint fusion and one underwent joint resurfacing. Discussion. These results suggest MIC has comparable early results to OC. Larger studies are required to further establish the benefits of MIC. Conclusion. Minimally invasive dorsal cheilectomy seems to offer a safe alternative to open cheilectomy with promising early results. Patient satisfaction with this procedure is very high

Introduction. Minimally Invasive foot surgery remains controversial. Potential benefits include a reduced incidence of wound complications, faster return to employment and normal footwear. There are no studies published regarding the results of minimally invasive dorsal cheilectomy. Patients and Methods. Thirty eight patients with painful grade I hallux rigidus underwent dorsal cheilectomy between April 2006 and June 2010. Minimally invasive cheilectomy (MIC) was introduced in August 2009. AOFAS scores, satisfaction, return to normal shoes and employment were assessed. Results. Twenty two patients had open cheilectomy (OC) whilst 16 had MIC. Mean follow-up was 6 months for the MIC group and 35 months for the OC group. Mean AOFAS score was 75/100 (SD 17) in the MIC group and 70/100 (SD 18). Patients rated their satisfaction as 9.1/10 for MIC and 8.6/10 for OC. There was no significant difference in time to return to normal shoes (P = 0.32) or employment (P = 0.07). Two patients (one MIS, one OC) had a superficial wound infection which resolved with oral antibiotics. One patient had a first metatarsophalangeal joint fusion in the MIS group. Two patients in the OC group went on to have a first metatarsophalangeal joint fusion and one underwent joint resurfacing. Discussion. These results suggest MIC has comparable early results to OC. Larger studies are required to further establish the benefits of MIC. Conclusion. Minimally invasive dorsal cheilectomy seems to offer a safe alternative to open cheilectomy with promising early results. Patient satisfaction with this procedure is very high

The October 2013 Foot & Ankle Roundup. 360 . looks at: Operative treatment of calcaneal fractures advantageous in the long term?; Varus ankles and arthroplasty; Reducing autograft complications in foot and ankle surgery; The biomechanics of ECP in plantar fasciitis; Minimally invasive first ray surgery; Alcohol: better drunk than injected?; Is it different in the foot?; It’s all about the temperature

Introduction Minimally invasive total knee arthroplasty has gained interest among total joint surgeons across the USA. It remains, however, somewhat unclear how to define minimally invasive. Small incisions may be a focal point of the surgery, but unless one is performing “limited incision surgery”, the skin does not define minimalness. The techniques and instrumentation for performing a minimally invasive total knee arthroplasty are presented. Methods The principles of a minimally invasive total knee arthroplasty procedure include: a small incision, a vastus-medialis split, mobilization of the patella without eversion, and the use of modified instruments that have been designed for use with standard implants. The implantation instruments are downsized versions of a standard system and are easily applied to the routine arthroplasty patient. Results The mid-vastus split appears to protect the quadriceps’ function and promote early recovery relative to the more traditional para-patellar arthrotomy. By avoiding patellar eversion altogether or only everting for a limited period, in extension, at the end of the case, elongation of the quadriceps fibers is avoided. These two measures appear protective and may promote early muscle recruitment during the post-operative recovery phase. The miniaturization of the familiar easier. Early review of post-operative radiographs has not revealed detriment to implant positioning. Conclusions While only developmental, this technique appears amenable to navigation systems that may further the minimalization by avoiding violation of the femoral and tibial canals. Minimally invasive total knee arthroplasty needs to be defined as a concept and as to what role it should play in a surgeon’s armamentarium. While in its infancy as a technique, the new instruments and refined surgical approach appear to allow rapid rehabilitation and patient satisfaction without sacrificing positioning or outcome. In relation to the conduct of this study, one or more of the authors has received, or is likely to receive direct material benefits

Objectives: Minimally invasive hip arthroplasty (MIHA) has become a trend in last few years. The orthopaedic literature is deficient in well designed scientific studies to support the idea that MIHA provides superior outcomes compared with Total Hip Arthroplasty(THA) performed through standard incisions. We have attempted a comprehensive quantitative review of the published literature to assess the methodology of those studies and reported surgical outcomes. Methods: We conducted a comprehensive literature search of different online databases. All relevant articles in peer-reviewed journals were retrieved except those not mentioning outcomes, case reports, review of literature and letters to editors. Two independent authors analyzed these articles for year of publication, type of study, patient numbers, surgical method, follow-up, complications and patient satisfaction. Each article was also graded using a validated methodology score; Coleman’s Ten Criteria to assess the quality of study. Results: 38 studies met our inclusion criteria which contained a total of 6434 hip arthroplasties.78.5% (4031) of these were MIHAs. There was significantly less intra-operative blood loss with MIS technique. However no significant difference was noted between the two groups with respect to operating time, the mean length of hospital stay, pain score, dislocation and revision rates, neurological injury and incidence of peri-operative fracture. In addition the patient characteristics and surgeon experience had a significant effect on outcome. Scores were predominantly low for quality of the studies with patient numbers, follow up time and validated outcome measures being the weakest areas. Conclusion: Minimally invasive hip arthroplasty is clearly in its infancy and continually evolving with new techniques and instruments being developed to treat a broader range of patients. At the present time there is still a lack of quality evidence to advocate its expansion. The better designed studies in fact suggest that it should perhaps be limited further to recognised expert centres. The complication rates and learning curve may be altered by changes in training and adapting surgical techniques. We emphasize the need for meticulous design in future studies comparing the outcomes of these two procedures

Purpose. Minimally invasive anterolateral approach (ALA) for total hip arthroplasty (THA) has gained popularity in recent years as better postoperative functional recovery and lower risk of postoperative dislocation are claimed. However, difficulties for femur exposure and intraoperative complications during femoral canal preparation and component placement have been reported. This study analyzes the anatomical factors likely to be related with intraoperative complications and the difficulties of access noted by the surgeons through a modified minimally invasive ALA. The aim is to define the profile for patient at risk of intraoperative complications during minimally invasive ALA. Methods. We retrospectively included 310 consecutive patients (100 males, 210 females) who had primary unilateral THA using the same technique in all cases. The approach was performed between the tensor fascia lata and the gluteus medius and minimus, without incising or detaching muscles and tendons. Posterior translation was combined to external rotation for proximal femur exposure (Fig. 1). All patients were reviewed clinically and radiologically. For the radiological evaluation, all patients underwent pre- and postoperative standing and sitting full-body EOS acquisitions. Pelvic [Sacral slope, Pelvic incidence (PI), Anterior pelvic plane angle] and femoral parameters were measured preoperatively. We assessed all intraoperative and postoperative complications for femoral preparation and implantation. Intraoperative complications included the femoral fractures and difficulties for femoral exposure (limitations for exposure and lateralization of the proximal femur). The patients were divided into two groups: patients with or without intraoperative complications. Results. Ten patients (3.2%) had intraoperative femoral fractures (greater trochanter: 2 cases, calcar: 8 cases). Five fractures required additional wiring. Difficult access to proximal femur was reported in the operative records for 10 other patients (3.2%). There was no difference in diagnosis, age, sex, BMI between the patients with or without intraoperative complications. No significant group differences were found for surgical time, and blood loss. Patients with intraoperative complication, presented a significantly lower pelvic incidence than patients without intraoperative complications (mean PI: 39.4° vs 56.9°, p<0.001). The relative risk of intraoperative complications in patients with low PI (PI<45°) was more than thirteen times (relative risk; 13.3, 95% CI= 8.2 to 21.5. p<0.001) the risk for patients with normal and high PI (PI>45°). Conclusions. Anterolateral approach for THA implantation in lateral decubitus is reported to have anatomical and functional advantages. Nevertheless, the exposure of the femur remains a limitation. This study highlights a significant increased risk in case of low PI less than 45°. This specific anatomical pattern reduces the local working space as the possibility for posterior translation and elevation of the proximal femur is less on a narrow pelvis. This limitation is due to the length and the orientation of the hip abductor and short external rotator muscles related to the relative positions of iliac wing and greater trochanter (Fig. 2). This study points out the importance of pelvic incidence for the detection of anatomically less favourable patients for THA implantation using ALA. For any figures or tables, please contact the authors directly

Background. Treating fractures is expensive and includes a long post-operative care. Intra-articular fractures are often treated with open surgery that require massive soft tissue incisions, long healing time and are often accompanied by deep wound infections. Minimally invasive surgery (MIS) is an alternative to this but when performed by surgeons and supported by X-rays does not achieve the required accuracy of surgical treatment. Methods. Functional and non-functional requirements of the system were established by conducting interviews with orthopaedic surgeons and attending fracture surgeries at Bristol Royal Infirmary to gain first-hand experience of the complexities involved. A robot-assisted fracture system (RAFS) has been designed and built for a distal femur fracture but can generally serve as a platform for other fracture types. Results. The RAFS system has been tested in BRL and the individual robots can achieve the required level of reduction positional accuracy (less than 1mm translational and 5 degrees of rotational accuracy). The system can simultaneously move two fragments. The positioning tests have been made on Sawbones. Conclusions. The proposed approach is providing an optimal solution by merging the fracture reduction knowledge of the orthopaedic surgeon and the robotic system's precision in 3D. Level of Evidence. The current level of evidence is limited and based on the Sawbones testing. Acknowledgement. This is a summary of independent research funded by the NIHR's i4i Programme. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health