Aims. Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. Materials and Methods. A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6). Results. At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected. Conclusion. Our results indicate that FiberTape increases the biomechanical performance of intra-articular ligament reconstructions in a verified rabbit model at eight weeks. Within this period, FiberTape did not adversely affect bone tunnel healing or invoke a prolonged elevation in inflammation. Cite this article: Bone Joint J 2019;101-B:1238–1247

Abstract. Introduction. We present a case series of patients that underwent knee ligament reconstruction with graft reinforcement using FibreTape (Arthrex), a 2mm wide non-biodegradable polyethylene tape. Outcomes and safety of this novel technique are reported. Methods. Data were collected from a prospectively maintained database from 03/2011 to 11/2019. All skeletally mature patients that underwent reinforced knee ligament reconstruction surgery at Basingstoke and North Hampshire Hospital were included. The cohort was interrogated for outcomes including failure, complications, and subjective patient reported outcomes at 6,12 and 24 months postoperatively. Results. 438 patients were eligible. The mean age was 33.4 years and 68% of them were males. This included 171 ACL reconstructions, 96 ACL with anterolatreal ligament reconstructions, 59 bicruciate reconstructions, 30 ACL with posterolateral corner, 49 posterior cruciate ligament with one other ligament and 33 other ligament reconstruction. Allograft was used for 125 patients. 338 cases related to primary reconstruction. The overall complication rate was 5.3%, with a 2.1% re-rupture rate. There were 9 patients with a re-rupture and 5 of them had undergone multiligament reconstruction. We found a statistically significant improvement in all subjective scoring indices post-operatively up to 2 years. There were no complications directly related to the use of ligament reinforcement. Conclusion. Graft reinforcement is a safe option in the management of knee ligament injuries. Encouraging results were observed in patient reported outcomes. Reinforcement is technically reproducible and may represent an answer for graft failure rates, especially in multiligament reconstructions. Further application and evaluation is necessary to confirm its benefit

Abstract. Introduction. Historic MCL reconstruction techniques focused on the superficial MCL to restore valgus stability while overlooking tibial external rotation and the deep MCL. This study assessed the ability of a contemporary medial collateral ligament (MCL) reconstruction and a deep MCL (dMCL) reconstruction to restore rotational and valgus knee stability. Methods. Six pairs fresh-frozen cadaveric knee specimens with intact soft tissue were tested in four states: 1) intact 2) after sMCL and dMCL sectioning, 3) contemporary MCL reconstruction (LaPrade et al), and 4) dMCL reconstruction. In each state, four loading conditions were applied at varying flexion angles: 8Nm valgus torque, 5Nm tibial external rotation torque, 90N anterior drawer, and combined 90N anterior drawer plus 5Nm tibial external rotation torque. Results. Transection of the sMCL and dMCL resulted in increased laxity with valgus torque, external rotation torque, and combined anterior drawer plus external rotation. dMCL reconstruction restored external rotation stability to intact levels throughout all degrees of flexion but did not restore valgus stability at any flexion angle. Contemporary MCL reconstruction restored valgus and external rotation stability at 0° and 20° and valgus stability at 40°. In the combined anterior drawer plus tibial external rotation trial, the dMCL restored stability at 20° and improved stability between 40° and 90° flexion. Conversely, the contemporary MCL reconstruction did not restore stability at any degree of flexion. Conclusion. Deep MCL reconstruction restored rotational stability to the knee throughout range of motion but not valgus stability. The contemporary MCL reconstruction restored stability only near full extension

Abstract

Purpose

To assess the midterm functional results after Medial Patellofemoral Ligament (MPFL) reconstruction with single semitendinosis autograft in patients with patellofemoral instability.

The purpose of this study was to report the outcome of ‘isolated’ anterior cruciate ligament (ACL) ruptures treated with anatomical endoscopic reconstruction using hamstring tendon autograft at a mean of 15 years (14.25 to 16.9). A total of 100 consecutive men and 100 consecutive women with ‘isolated’ ACL rupture underwent four-strand hamstring tendon reconstruction with anteromedial portal femoral tunnel drilling and interference screw fixation by a single surgeon. Details were recorded pre-operatively and at one, two, seven and 15 years post-operatively. Outcomes included clinical examination, subjective and objective scoring systems, and radiological assessment. At 15 years only eight of 118 patients (7%) had moderate or severe osteo-arthritic changes (International Knee Documentation Committee Grades C and D), and 79 of 152 patients (52%) still performed very strenuous activities. Overall graft survival at 15 years was 83% (1.1% failure per year). Patients aged < 18 years at the time of surgery and patients with > 2 mm of laxity at one year had a threefold increase in the risk of suffering a rupture of the graft (p = 0.002 and p = 0.001, respectively). There was no increase in laxity of the graft over time.

ACL reconstructive surgery in patients with an ‘isolated’ rupture using this technique shows good results 15 years post-operatively with respect to ligamentous stability, objective and subjective outcomes, and does not appear to cause osteoarthritis.

We have undertaken a randomized clinical trial comparing two methods of reconstruction of the anterior cruciate ligament in patients with chronic instability. We used an ipsilateral bone-patellar-tendon-bone autograft in 27 patients and the Ligament Advancement Reinforcement System (LARS) artificial ligament in 26. Assessment before and at two, six, 12 and 24 months after surgery, included the history, physical examination, a modified International Knee Documentation Committee (IKDC) score, the Tegner score, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and instrumented laxity testing.

There were no cases of reactive synovitis or of infection of the knee, and there was no difference regarding the failure rate between the two groups. The IKDC showed no significant differences between the two groups at any stage of the follow-up. The KOOS evaluation showed consistently better results in all subscales for the LARS group during the first year of follow-up. After 24 months these differences were no longer evident. Instrument-tested laxity was greater in the LARS group at all stages of follow-up, but the differences were not significant at 24 months.

Our findings suggest that at follow-up at 24 months the LARS ligament seems to be a satisfactory treatment option, especially when an early return to high levels of activity is demanded.

Abstract. Introduction. The aim of this study was to determine if elite athletes could return to professional sport after MCL or PLC reconstruction using LARS ligaments and to demonstrate the safety and efficacy of LARS by reporting sport longevity, subsequent surgeries and complications. Methods. A retrospective review of all extra-articular knee ligament reconstructions in elite athletes utilising LARS ligaments by 3 knee surgeons between January 2013 and October 2020 was undertaken. Return to play (RTP) was defined as competing at professional level or national/ international level in amateur sport. Results. Sixty-four (84.2%) MCL and 12 (15.8%) PLC reconstructions utilising LARS in elite athletes were included. 52 (68.4%) underwent concomitant cruciate(s) reconstruction. The mean age was 25.1 years (SD +/− 4.50. Most were football (35, 46.1%) or rugby players (35, 46.1%). Sixty-seven athletes (88.2%) RTP with 65 (97.0%) of these playing at the same or higher Tegner level. 56 (83.6%) and 20 (57.1%) were still playing at 2 and 5 years post-surgery. Six (7.9%) players (5 of whom RTP) required further surgery relating to the LARS / metalwork and there was one case of adverse local inflammatory reaction to the synthetic material. There was one MCL re-rupture, sustained 4 years after RTP. Conclusion. Utilising LARS in extra-articular knee ligament reconstructions allows 88.2% of athletes, with a variety of knee ligament injuries, to return to elite sport. The low morbidity rates coupled with 57% of athletes still playing 5 years post-surgery suggests the LARS is safe and effective in these cases

Aims. The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA. Methods. This study was a retrospective case-control study using the UK Biobank to identify individuals reporting a history of cruciate ligament surgery. Data from verbal history and procedural codes recorded through the NHS were used to identify instances of TKA. Patient clinical and genetic data were used to identify risk factors for progression from cruciate ligament surgery to TKA. Individuals without a history of cruciate ligament reconstruction were used for comparison. Results. A total of 2,576 individuals with a history of cruciate ligament surgery were identified, with 290 (11.25%) undergoing TKA. In patients with prior cruciate ligament surgery, prevalence of TKA was 0.75% at age 45 years, 9.10% at age 65 years, and 20.43% at age 80 years. Patients with prior cruciate ligament surgery were 4.6 times more likely to have undergone TKA by age 55 years than individuals without prior cruciate ligament surgery. In the cruciate ligament surgery cohort, BMI > 30 kg/m. 2. (odds ratio (OR) 4.01 (95% confidence interval (CI) 2.74 to 5.87)), a job that always involved heavy manual or physical labour (OR 2.72 (95% CI 1.57 to 4.71)), or a job that always involved walking and standing (OR 2.58 (95% CI 1.58 to 4.20)) were associated with greater TKA odds. No single-nucleotide polymorphism (SNP) was associated with risk of TKA following cruciate ligament surgery. Conclusion. Patients with a history of prior cruciate ligament surgery have substantially higher risk of TKA and undergo arthroplasty at a relatively younger age than individuals without a history of prior cruciate ligament surgery. Physically demanding work and obesity were associated with higher odds of TKA after cruciate ligament surgery, but no SNP was associated with risk of TKA. Cite this article: Bone Joint J 2024;106-B(3):249–255

Abstract. Background. Osteochondral allograft (OCA) transplantation is a clinically and cost-effective option for symptomatic cartilage defects. In 2017 we initiated a program for OCA transplantation for complex chondral and osteochondral defects as a UK tertiary referral centre. Aim. To characterise the complications, re-operation rate, graft survivorship and clinical outcomes of knee OCA transplantation. Methodology. Analysis of a prospectively maintained database of patients treated with primary OCA transplantation from 2017 to 2021 with a minimum of one-year follow-up. Patient reported outcome measures (PROMs), complications, re-operations and failures were evaluated. Results. 37 patients with 37 knee OCA procedures were included (mean age 31.6 years [16–49 years]). Mean BMI 26.6 kg/m2 (19.1–35.9 kg/m2). The mean chondral defect size was 3cm2 (1.2–7.3 cm2). Mean duration of follow-up was 3.1 years (1–5.3 years). 16 patients underwent meniscal allograft transplantation (MAT), 6 underwent osteotomy and 4 underwent ligament reconstruction as concurrent procedures. Significant improvements in mean PROMs were noted at 12 months. 16 patients had reoperations of which 5 had more than one surgery. Of these patients 6 were related to OCA (mainly debridement and revision OCA in one patient), and the remainder were related to additional procedures including removal of plate in 2 patients. The overall failure rate was 1 in 37 patients (3%). Conclusions. Early experience of OCA as a treatment option for complex chondral and osteochondral lesions in the knee shows satisfactory results. The reoperation rate is high but at mean follow-up of 3.1 years the survival rate was 97%

Abstract. Introduction. Derby technique for posterolateral corner (PLC) reconstruction uses a doubled gracilis autograft to reconstruct the popliteo-fibular ligament (PFL) and a split biceps tendon transfer to reconstruct the lateral collateral ligament (LCL). We report midterm outcomes of a case series who underwent PLC reconstruction. Methodology. A retrospective review of 27 patients who underwent PLC reconstruction from 2012 until 2018 was performed (6 females, 21 males, median age 26). Median time interval from injury to primary procedure was 10 months. Outcomes were recorded as per clinical assessment and outcome scores. Results. All patients had no varus laxity in full knee extension. Similarly, at 30° of knee flexion, 25 patients (92.5%) had no varus laxity and 2 patients (7.5%) had grade 1 laxity. No patients demonstrated abnormal external rotation at final follow up. Outcome scores were obtained from 17 patients who underwent primary ligament reconstruction at a mean follow up of 72 months postoperatively. The mean Lysholm score was 94 +/-5.5 (72–100) and mean subjective IKDC score was 78/87 (89.6%) (51–87). 90% of our patients had gained normal or nearly normal IKDC scores on returning to routine activities of daily living and sports following surgery compared to their pre-injury status. Conclusion. Our technique enables an anatomical LCL & PFL reconstruction in isolation or in combination with ACL/PCL reconstruction or to augment an acute repair without contralateral graft harvest or allograft. The functional knee scores demonstrated in this cohort are comparable and in fact superior to previously published knee scores after PLC reconstruction

Aims. Anterior cruciate ligament (ACL) and multiligament knee (MLK) injuries increase the risk of development of knee osteoarthritis and eventual need for total knee arthroplasty (TKA). There are limited data regarding implant use and outcomes in these patients. The aim of this study was to compare the use of constrained implants and outcomes among patients undergoing TKA with a history of prior knee ligament reconstruction (PKLR) versus a matched cohort of patients undergoing TKA with no history of PKLR. Patients and Methods. Patients with a history of ACL or MLK reconstruction who underwent TKA between 2007 and 2017 were identified in a single-institution registry. There were 223 patients who met inclusion criteria (188 ACL reconstruction patients, 35 MLK reconstruction patients). A matched cohort, also of 223 patients, was identified based on patient age, body mass index (BMI), sex, and year of surgery. There were 144 male patients and 79 female patients in both cohorts. Mean age at the time of TKA was 57.2 years (31 to 88). Mean BMI was 29.7 kg/m. 2. (19.5 to 55.7). Results. There was a significantly higher use of constrained implants among patients with PKLR (76 of 223, 34.1%) compared with the control group (40 of 223, 17.9%; p < 0.001). Subgroup analysis showed a higher use of constrained implants among patients with prior MLK reconstruction (21 of 35, 60.0%) compared with ACL reconstruction (55 of 188, 29.3%; p < 0.001). Removal of hardware was performed in 69.5% of patients with PKLR. Mean operative time (p < 0.001) and tourniquet time (p < 0.001) were longer in patients with PKLR compared with controls. There were no significant differences in rates of deep vein thrombosis, pulmonary embolism, infection, transfusion, postoperative knee range of movement (ROM), or need for revision surgery. There was no significant difference in preoperative or postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) scores between groups. Conclusion. Results of this study suggest a history of PKLR results in increased use of constrained implants but no difference in postoperative knee ROM, patient-reported outcomes, or incidence of revision surgery. Cite this article: Bone Joint J 2019;101-B(7 Supple C):77–83

We report the clinical results of seven consecutive allograft knee ligament reconstructions using Achilles tendon prepared using a chemical treatment process. Results have been disappointing with six clinical failures at short durations of follow-up. All allografts are not the same and the method of tissue preparation may have important consequences for clinical outcomes. Debate regarding the use of allograft or autograft tissue for knee ligament reconstruction continues. A variety of allograft tissues are available from commercial and NHS sources: fresh frozen, freeze dried, irradiated or chemically prepared. There are gaps in the literature with respect to clinical outcomes for these various methods of graft preparation. A recent systematic review indicated similar short-term clinical outcomes for fresh frozen allografts and autografts. The senior author began using allograft Achilles tendon for revision ACL reconstruction or primary multiple ligament reconstruction in 2007. Tissues were obtained from a commercial supplier. These tissues had been harvested in Eastern Europe, transported to the USA and sterilised using a patented “Biocleanse” chemical treatment process. This involves sequential ultrasonic baths of detergent, peroxide and alcohol for fixed periods of time along with pressure and vacuum cycles. Between April 2007 and April 2009, 7 allograft ligament reconstructions were performed in 5 knees. These comprised 5 ACL and 2 LCL reconstructions. At follow up of between 4 months and 2 years, clinical failure of 6 grafts has been observed. We are aware of one previous series of results for ACL reconstructions using chemically sterilised and irradiated allograft tissues. A 45% graft failure rate was reported. We have not been able to identify any clinical outcome studies for grafts prepared using the “Biocleanse” process. Our results have prompted us to change to UK sourced, donor screened allografts, which are fresh frozen after decontamination with 70% ethanol

Aims. The aim of this consensus was to develop a definition of post-operative fibrosis of the knee. Patients and Methods. An international panel of experts took part in a formal consensus process composed of a discussion phase and three Delphi rounds. Results. Post-operative fibrosis of the knee was defined as a limited range of movement (ROM) in flexion and/or extension, that is not attributable to an osseous or prosthetic block to movement from malaligned, malpositioned or incorrectly sized components, metal hardware, ligament reconstruction, infection (septic arthritis), pain, chronic regional pain syndrome (CRPS) or other specific causes, but due to soft-tissue fibrosis that was not present pre-operatively. Limitation of movement was graded as mild, moderate or severe according to the range of flexion (90° to 100°, 70° to 89°, < 70°) or extension deficit (5° to 10°, 11° to 20°, > 20°). Recommended investigations to support the diagnosis and a strategy for its management were also agreed. Conclusion. The development of standardised, accepted criteria for the diagnosis, classification and grading of the severity of post-operative fibrosis of the knee will facilitate the identification of patients for inclusion in clinical trials, the development of clinical guidelines, and eventually help to inform the management of this difficult condition. Cite this article: Bone Joint J 2016;98-B:1479–88

Purpose. The purpose of this study was to assess radiologically the absorption of a poly L-lactide bioabsorbable interference screw used in anterior ligament reconstruction. Methods. A case series of ten sequential patients undergoing anterior ligament reconstruction with a four-strand hamstrings technique were assessed with MRI scans at one, two, four, seven and ten years postoperatively. The scans were reported by an independent radiologist, with respect to resorption of the screw and post resorption changes in the bone. Fixation of the graft in ACL surgery is varied from metal interference screw, resorbable screws made of PLLA, and staple fixation. The advantage of resorbable screws allow imaging of the knee postoperatively, and the perceive benefit of screw resorption and replacement with host bone. Results. No resorption had occurred after 4 years in any of the patients. By seven years screw absorption was complete in seven patients and progressive in three. Five patients displayed new bone formation within the tibial tunnel. Of the five patients with no demonstrable new bone formation, a fluid collection was present within the tibial tunnel. In one of these patients, MRI revealed formation of a ganglion beyond the limit of the tunnel. We will present the final data after ten years. Conclusions. This study has shown that the bioabsorbable screws take longer to resorb than initial in vitro data. It is unclear as to whether any ganglion formation is related to the resorption, or the presence of the hamstring graft in the tunnel. The theoretical advantages of bio-absorbable screws must be weighed against these findings

Purpose. We conducted a prospective study to investigate the role of the LARS ligament system to reconstruct the posterior cruciate ligament and the postero-lateral corner of the knee. We present a prospective single surgeon case series to evaluate early clinical and functional outcomes of postero-lateral corner and posterior cruciate ligament reconstruction in the knee using the LARS (ligament Augmentation and Reconstruction System) artificial ligament. 23 patients with multi-ligament knee injuries or isolated PCL injuries were treated with a mean follow up of 8 months (range: 2-37 months). Outcomes were assessed using the modified International Knee Documentation Committee score, and a modified Tegner- Lysholm score. 2 patients had acute reconstructive surgery within 7 days of injury, 5 patients within 3 months (semi-acute) and 16 were chronic cases that were operated on after three months from the date of injury. The LARS ligament reconstruction achieved a significant improvement between preoperative and postoperative assessment in relation to knee stability, function and patient satisfaction. The sooner the patients were treated the greater the improvements in functional scores were noted. Most patients achieved a full functional range of movement within six months. We had 2 complications, one superficial wound infection and one stiff knee requiring a manipulation. To date we have had no LARS ligament failures. In the short term the LARS functions well, with high clinical patient satisfaction, no signs of progressive laxity, synovitis or failure. We found no significant difference in functional score post reconstruction between the isolated PCL reconstructions and the multi ligament reconstructions. Our results show no early signs of the problems associated with synthetic grafts used in the past. Such grafts appear to be an attractive alternative to the use of autografts and allografts

Aims. The aim of this study was to identify risk factors for prosthetic joint infection (PJI) following total knee arthroplasty (TKA). . Patients and Methods. The New Zealand Joint Registry database was analysed, using revision surgery for PJI at six and 12 months after surgery as primary outcome measures. Statistical associations between revision for infection, with common and definable surgical and patient factors were tested. Results. A total of 64 566 primary TKAs have been recorded on the registry between 1999 and 2012 with minimum follow-up of 12 months. Multivariate analysis showed statistically significant associations with revision for PJI between male gender (odds ratio (OR) 1.85, 95% confidence interval (CI) 1.24 to 2.74), previous surgery (osteotomy (OR 2.45 95% CI 1.2 to 5.03), ligament reconstruction (OR 1.85, 95% CI 0.68 to 5.00)), the use of laminar flow (OR 1.6, 95% CI 1.04 to 2.47) and the use of antibiotic-laden cement (OR 1.93, 95% CI 1.19 to 3.13). There was a trend towards significance (p = 0.052) with the use of surgical helmet systems at six months (OR 1.53, 95% CI 1.00 to 2.34). Conclusion. These findings show that patient factors remain the most important in terms of predicting early PJI following TKA. Furthermore, we found no evidence that modern surgical helmet systems reduce the risk of PJI and laminar flow systems may actually increase risk in TKA. The use of this registry data assists the estimation of the risk of PJI for individual patients, which is important for both informed consent and the interpretation of infection rates at different institutions. . Take home message: Infection rates in TKA are related to both individual patient and surgical factors, and some modern methods of reducing infection may actually increase infection risk. . Cite this article: Bone Joint J 2016;98-B:334–40

Introduction. Anterior cruciate ligament (ACL) and multiligament knee (MLK) injuries increase the risk of development of knee osteoarthritis and eventual need for total knee arthroplasty (TKA). There is limited data regarding implant use and outcomes in these patients. The aim of this study was to compare the use of constrained implants and outcomes among patients undergoing TKA with a history of prior knee ligament reconstruction (PKLR) to a matched cohort of patients undergoing TKA with no history of PKLR. Methods. All patients with history of ACL or MLK reconstruction who underwent TKA between 2007–2018 were identified in a single institution registry. A matched cohort was identified based on patient age, body mass index (BMI), sex, and year of surgery. The primary outcome measure was utilization of constrained implants. Secondary outcomes included rates of deep vein thrombosis (DVT), pulmonary embolism (PE), infection, postoperative transfusion, postoperative knee range of motion (ROM), revision surgery, and patient reported outcomes (Knee Injury and Osteoarthritis Outcome Score for joint replacement (KOOS, JR). Results. There were 223 patients who met inclusion criteria (188 patients with prior ACL reconstruction, 35 patients with prior MLK reconstruction). Mean age at the time of TKA was 57.2 years (range 31–88). Mean BMI was 29.7 (range 19.5–55.7). Patients with PKLR had a lower Charleston Comorbidity Index compared to controls (p<0.0001). There was a significantly higher use of constrained implants among patients with PKLR (34.1%) compared to the control group (17.9%) (p<0.001). Subgroup analysis showed a higher use of constrained implants among patients with prior MLK reconstruction (60.0%) compared to ACL reconstruction (29.3%) (p<0.001). Removal of hardware at the time of TKA was performed in 69.8% of patients with PKLR. Mean operative time (p<0.001) and tourniquet time (p<0.001) were longer in patients with PKLR compared to controls. There were no significant differences in rates of DVT, PE, infection, transfusion, postoperative knee ROM, or need for revision surgery (p>0.05). There was no significant difference in preoperative or postoperative KOOS, JR scores between groups (p>0.05). Conclusion. Results of this study suggest a history of PKLR results in an increased utilization of constrained implants but no difference in post-operative knee ROM, patient reported outcomes, or incidence of revision surgery

Aims

This study aims to identify the top unanswered research priorities in the field of knee surgery using consensus-based methodology.

Aims

Meniscal allograft transplantation (MAT) for patients with symptomatic meniscal loss has demonstrated good clinical results and survivorship. Factors that affect both functional outcome and survivorship have been reported in the literature. These are typically single-centre case series with relatively small numbers and conflicting results. Our aim was to describe an international, two-centre case series, and identify factors that affect both functional outcome and survival.