Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding procedure, reporting poorer outcomes compared to the primary procedure. Identification of the cause of primary failure and a thorough pre-operative evaluation is required to plan the most appropriate surgical approach. 3D printing technology has become increasingly commonplace in the surgical setting. In particular, patient-specific anatomical models can be used to aid pre-operative planning of complicated procedures. We have conducted a qualitative study to gauge the interest amongst orthopaedic knee surgeons in using a 3D-printed model to plan revision ACL reconstructions.

A tibia and femur model was printed from one patient who is a candidate for the procedure. The binder jetting printing technique was performed, using Visijet PXL Core powder. 12 orthopaedic knee surgeons assessed the usefulness of the 3D-printed model compared to conventional CT images on a likert scale. 6 key steps of preoperative planning were assessed, including the size and location of the tunnel defects, the need for notchplasty, and whether a staged revision was required.

We found that surgeons preferred the 3D-printed model to conventional CT images only, and 83% of them would use such a model for both pre-operative simulation, and as an intra-operative reference. However, there were some variation in the perceived usefulness of the model in several areas assessed. This may reflect differences in individual approach towards planning of the procedure.

Our findings suggest that 3D-printed models could be a versatile pre-operative and intra-operative tool for complicated arthroscopic knee surgery. While 3D printing technology is becoming increasingly accessible and affordable, in-depth cost-effectiveness studies need to be conducted before it can be integrated into clinical. Further study would be needed to determine the clinical utility and economic cost-effectiveness of the 3D-printed model in revision ACL reconstruction.

Acute multiligament knee injuries (MLKI) are rare, high energy traumatic injuries associated with an increased risk of lower limb complications. The objectives of this study were to investigate the adequacy of clinical assessment for neurovascular status, compartment syndrome, and deep vein thrombosis in the emergency department (ED) following acute MLKI. The authors conducted a retrospective case note review of 19 patients with MLKI presenting at the ED of a Major Trauma Centre during a 7.5-year period between June 2009 and December 2016. MLKIs were diagnosed by MRI or examination under anaesthesia and confirmed intraoperatively. Arterial assessment consisted of documented capillary refill time, dorsalis pedis and posterior tibial pulse assessment (through palpation or Doppler ultrasound), and ankle-brachial pressure index (ABPI) calculation. Neural assessment was adequate if there was documented assessment of both sensory and motor function of the superficial peroneal, deep peroneal and tibial nerves individually. Data was collected for 19 patients (17 male, 2 female). The mean age was 34 (range: 14–61). The most common injury mechanism was road traffic accident. Neurovascular assessment was suboptimal in all categories: only one patient received a satisfactory lower limb neurological assessment and no patients received complete vascular assessments. Neurovascular assessment of multiligament knee injuries was suboptimal. Reasons for this included poor documentation and lack of certain specific clinical assessments, such as ABPI calculation. We propose the introduction of an acute knee injury pro forma highlighting the components of a full lower limb neurovascular examination to rectify this problem.

Statement of purpose. Cement fixation of total knee replacement (TKR) is commonly cited as being the gold standard, with better long-term survival rates when compared to uncemented fixation so the authors set out to analyse the longterm survivorship without aseptic loosening in a series of 471 uncemented TKR.

Background

The management of chondral lesions in the knee, especially in young fit patients, remains an area of considerable controversy. Articular cartilage repair or reconstruction techniques may offer these patients alternatives to arthroplasty or realignment osteotomy. The TruFit plug (Smith & Nephew, London, UK) is a synthetic biphasic polymer scaffold that is designed for implantation at the site of a focal chondral defect. It is intended to resorb and allow tissue ingrowth 6-9 months following implantation and may be placed either arthroscopically or via an open approach depending on the site of the lesion.

Improved surgical techniques and new fixation methods have revived interest in high tibial osteotomy surgery in recent years. Our aim was to review our first 59 cases. All patients underwent radiological and clinical review including pre and post operative scores.

Mean age at surgery was 43 (22-59) and mean follow up is 22 months.

The mean pre-operative limb alignment was 5.4° varus (range 1°-16°) with correction to 2° valgus (range -1° - 7°).

HTO is known to increase tibial slope and in this series the change in tibial slope from -5.2° (95%CI: -6.36 to -4.07)) to -7.8° (-8.83 to –6.89) was statistically significant. p= 0.0014 (Mann Whitney).

Patellar height is often reduced following opening wedge HTO and this is confirmed in our series. The Blackburne-Peel ratio changed from 0.74 to 0.58 and the Caton-Descamps from 0.83 to 0.7. Both were statistically significant at p<0.0001 and p=0.0001 respectively.

All scores improved post operatively, the knee injury and osteoarthritis outcome (KOOS) from 48 (8-91) to 73 (27-96), the Oxford knee score (OKS) from 25 (3-47) to 37 (9-48), and the EQ5D from 189809 (11221-32333) to 14138 (11111-22233) with the EQ5D VAS improving from 58 to 75. There was no correlation between change in limb alignment, tibial slope or patellar height and any of the scores used.

There were three superficial wound infections, and one non union which was treated with grafting and re fixation. Six patients have had their plate removed.

Improvement in clinical scores in these patients confirms that medial opening wedge HTO is a reliable joint preserving procedure in the short term and our surgical technique is reproducible and consistent with other published series.

Background

A retrospective review of all patients transferred by helicopter ambulance to the Great Western Hospital over a 20-month period between January 2003 and September 2004 was undertaken to establish the case-mix of patients (trauma and non-trauma) transferred and the outcome of their admission and length of hospital stay.

We performed a study to evaluate the material properties of a new cylindrical scaffold plug licensed for the treatment of osteochondral defects as prior to the removal of a core of normal femoral condylar bone, it is imperative that the biomechanical properties of replacement implant material are known.

TruFit CB plugs (Smith and Nephew) are resorbable material composed of polylactide-co-glycolide (PLG) copolymer, calcium-sulfate, polyglycolide (PGA) fibres and surfactant. The implants are 7mm, 9mm and 11mm cylindrical plugs. The stress/strain relationships of both the dual layer implant and the base layer material were examined. Compressive load testing at selected strain rates was performed in both confined and unconfined models in a substitute body fluid filled chamber.

Compressive failure was found to occur between 40–60% strain with maximum stresses at failure for the dual layer implants occurring at 5.5MPa (7mm), 5.8MPa (9mm) and at 8.5MPa (11mm). The mechanical strength under constrained loading conditions is higher than in unconstrained loading (compressive stress required to develop 5 percent strain being 0.6MPa unconfined to 1.1MPa confined for 7mm; 0.6MPa to 1.4MPa for 9mm and 1.0MPa to 3.2MPa for 11mm implants). This demonstrates the importance of a close press fit. The modulus of elasticity was calculated at 50 MPa (7mm), 60 MPa (9mm) and 80 MPa (11mm). The larger the plug size, the higher the strength shown under test conditions at all strain rates.

Prior to this study, the material properties of this implant have not been characterized. The Young’s moduli of the implants are in keeping with previous estimated values for successful regeneration of cartilage within a synthetic scaffold. The biomechanical properties described in this study will help to guide surgeons in TruFit CB use and guide the rehabilitation programmes of those patients who have had osteochondral lesions treated with TruFit CB scaffold plugs.

The outcome of arthroscopic ankle fusion has been favourably reported in the literature. The technique allows for early weight-bearing and results in fusion earlier than that of open techniques. All authors state that it a demanding procedure that has a significant learning curve. The purpose of this presentation is to report on that learning curve by analysing the first two years experience of one surgeon. Technical details, difficulties encountered and outcomes are described.

We analysed the results of arthroscopic ankle fusion in 14 consecutive ankles in 13 patients over a two-year period. Average age at fusion was 59 years. There were 12 male patients and one female. Indication for surgery was osteoarthritis in all patients. All were non-smokers at the time of surgery. Anti-inflammatory drugs were not prescribed on discharge, All patients underwent pre-operative sciatic nerve block using a nerve stimulator. Fixation of the fusion was performed with two screws in 13 ankles and a single screw in one. Mean tourniquet time was 117 minutes (first 4 cases averaged 124 minutes; last 4 averaged 105 minutes). Mean hospital stay was a single night. All patients were treated post-operatively with plaster cast immobilisation for two weeks (non-weight bearing). Subsequently, they were instructed to fully weight bearing as tolerated in a removable walking boot.

Radiological union was achieved in 11 ankles within 3 months. One ankle fused at between 9–12 months post-operatively. One ankle failed to unite due to inadequate joint access and preparation and underwent later open revision with bone grafting. One case of superficial portal wound infection treated successfully with antibiotics. No thrombo-embolic events. All patients had excellent or good clinical results at last follow up.

Patient selection issues and intra-operative learning points are discussed. With adequate training, arthroscopic ankle fusion is a safe and reliable technique.

The level of accuracy and precision required for consistently good surgical results will vary depending upon the characteristics of surgical task being undertaken. Training surgeons to achieve these results rapidly and effectively is a continuing challenge. Resurfacing arthroplasty for cam type deformity (a common cause of early osteoarthritis) is a technically demanding operation. We considered it desirable that the operation should be performed within +/− 10¡ of the desired angular orientation, and +/− 6mm of entry point translation in 95% of cases. To achieve that level of accuracy, without learning slowly on real patients, technological aids are now available. Using 3 models of varying severity of cam, we assessed the efficacy of 3 systems of instrumentation in delivering the level of accuracy and precision that is needed to ensure the excellent results that this surgeon and patient group expects.

Background. Patients with severe osteoarthritis of the knee often have to endure many months of pain and limited function whilst waiting for surgery. Measures that can improve quality of life and knee function while on waiting lists are worth employing and may improve post-operative recovery. This study was designed to evaluate the effects of standardised western acupuncture and supervised exercise therapy on pain control and functional ability in patients with severe osteoarthritic knee pain awaiting knee arthroplasty.

Methods. A three arm, single blind, randomised controlled trial was devised and took place at the Great Western Hospital, Swindon, UK. 181 patients awaiting knee arthroplasty met eligibility criteria and were entered into the trial. Block computerized randomisation was used to allocate patients to one of three treatment groups using a blinded third party. The three treatment groups were acupuncture for six weeks; supervised exercise therapy for six weeks or standardised advice. Outcome measures were assessed at 7 and 12 weeks following the initiation of treatment. The main outcome measures used were the Oxford Knee Score questionnaire, a 50 meter timed walk and duration of hospital stay following knee arthroplasty. Statistical analysis was performed with one way variance (ANOVA) analysis by intention to treat. Bonferroni method was used for analysis of statistically significant group differences.

Results. There was no baseline difference between groups. At 7 weeks there was a 10% reduction in Oxford Knee Score in the acupuncture group and a significant difference between the acupuncture and the other two groups: mean (SD) acupuncture 36.8 (7.2); physiotherapy 39.2 (8.2); control 40.3 (8.48) (p=0.0497). The supervised exercise group had a lower mean 50 meter walking time (50.3 seconds SD 17.7) compared to the acupuncture group (54.9 seconds SD 17) and the control group (58.4 seconds SD 25.2). Both these effects were still present but diminished at twelve weeks. There was a trend (p=0.0984) towards a shorter inpatient stay of one day for the physiotherapy group (mean 6.5 days SD 2.0) compared to the acupuncture group (mean 7.77 days SD 3.96).

Conclusions. Acupuncture can provide short-lived pain relief and improvement in function in patients with severe knee osteoarthritis awaiting knee arthroplasty. Supervised exercises lead to improvement in mobility. This functional improvement may decrease duration of hospital stay. Both interventions can be delivered safely and effectively in an outpatient group setting in a district general hospital and appear to be worthwhile for patients on the waiting list for surgery. Further evaluation of the effects of both treatments delivered simultaneously is planned.

Background: We have devised a modified Pivot Shift test with which to assess ACL deficiency which does not require forced tibio-femoral subluxation. The test is scored on patient reaction to the initiation of the pivot shift without actually having to elicit that ‘shift’ which can be painful. We call the test the Pivot Apprehension test.

Methods: We retrospectively analysed a cohort of 81 patients who were potentially ACL deficient and sought orthopaedic intervention over a period of 3 years and correlate their initial ‘pivot apprehension’ score with the degree of ACL deficiency found at subsequent arthros-copy and/or MRI.

Results: Using contingency tables and Fishers Exact test we calculate that the test has a positive predictive value (for predicting ACL Rupture) of 94% (p=0.026) and a sensitivity of 89% (Specificity 60%). Linear Regression analysis shows a correlation coefficient (r) of 0.47 (p=0.0008).

Conclusion: The data we have collected in this study show that the ‘Pivot Apprehension Score’ is a clinical tool with a high positive predictive value for ACL injury which provides the same information as the Pivot shift test without having to cause painful tibio-femoral sub-luxation thus obviating the clinical need to elicit ‘pivot shift’ in the conscious patient.

Introduction: Chondro-epiphyseal cartilage is generally resistant to vascular invasion. At the time of formation of the secondary ossification center in skeletal ‘long’ bones, the anti-angiogenic nature of cartilage is altered in favor of angiogenesis and vascular invasion takes place. We studied the control of this angiogenic ‘switch’ by experimentally investigating two factors which might influence vascular invasion. MMP 9 is a 92Kda gelatinase which degrades collagen types IV, V and X and gelatin (denatured collagen). It has been implicated in the control of endochondral ossification at the growth plate and has been shown to modulate endothelial cell morphogenesis. Basic Fibro-blast Growth Factor (b-FGF) is a cytokine with well established angiogenic capability and has also been implicated in the development of the growth plate. We investigated whether MMP-9 caused an effect on the development of the vasculature of the chondro-epiphysis of neo-natal rabbits and compared this to the effects of b-FGF.

Materials and Methods: The CAM Culture consists of placing a small tissue explant onto the the chorioallantoic membrane of 10 day-old chick embryos and continuing culture for a further 10 days. CAM derived vessels will invade the tissue, unless anti-angiogenic factors are present. Hence, CAM culture is used as an assay system for angiogenesis and factors that will influence it. We utilized the CAM culture model to investigate vascular in-growth into explants of femoral and humeral heads from 4 day old postnatal rabbits to test the influence of MMP-9 and b-FGF. A small nylon membrane, pre-soaked in a solution containing the factor, was placed on to a tangential cut across the perichondrium. The explant was then cultured on the CAM for 3–10 days.

Results: In control epiphyses, the in-growth of CAM derived blood vessels was rare and invasion of cartilage canals through the perichondrium seldom occurred, thus confirming the anti-angiogenic nature of epiphyseal cartilage. The initial presence of MMP 9 caused a tremendous increase in the de novo vascular invasion. MMP 9 treated epiphyses contained numerous large cartilage canals. In b-FGF treated epiphyses, a greater level of vascular in-growth was seen compared with controls, but this was not as marked as with MMP 9.

Our findings indicate that b-FGF and perhaps, more interestingly, MMP-9 are implicated in the activation of the angiogenic ‘switch’ at the chondroepiphysis leading to vascular invasion. The fact that MMP-9 can act as a stimulator to angiogenesis is a novel finding. The mechanism of action remains unclear although it is possible that it is involved in the deactivation of inhibitors of vasculogenesis or the activation of angiogenic factors, or both.