Introduction. The use of a mobile-bearing knee system is increasing in modern total knee arthroplasty (TKA). Mobile-bearing TKA improves kinematics and is reliable and capable of providing substantial benefit for patients. The aim of this study was to report independent long term results of uncemented low contact stress (LCS) mobile bearing total knee replacement. Methodology. We examined the outcome of 138 consecutive patients who underwent uncemented LCS total knee replacement between 1996 and 2000. Oxford knee score was noted. Results. 138 patients underwent LCS total knee replacement during this period. The mean age was 71(37-90) years. 34 patients died and 104 patients were included in the study. The mean follow up was 10 (8-12) years. There was a significant improvement in the postoperative knee scores (P<0.001). 2 knees were revised, one due to infection and due to the subsidence of the tibial tray. Conclusion. The study has demonstrated excellent long term survivorship of the uncemented LCS total knee replacement irrespective of the deformity and diagnosis

The early surgical management of the anterior cruciate ligament (ACL) tears in children remains controversial. The argument for nonoperative treatment is driven by concerns about the risk of growth arrest caused by a transphyseal procedure. On the other hand, early surgical reconstruction is favoured because of poor compliance with conservative treatment and increased risk of secondary damage due to instability. This paper reports a series of 39 very young children who had an ACL reconstruction using a transphyseal procedure with a hamstring graft. Patients were followed to skeletal maturity or for a minimum of three years. Only those patients with either a chronological age less than 14 years or with a Tanner stage of 1 and 2 of puberty were included in the study. Thirty children were Tanner 1 or 2 and nine were Tanner 3-4 but were younger than 14. The mean age at operation was 12.2 years (Range 9.5-14.2, Median 12.4). The mean follow up was 60.7 months (range 36-129, median: 51) months. Thirty four patients had attained skeletal maturity at the last follow up. The mean Lysholm score improved from 72.4 pre-operatively to 95.86 postoperatively (p<0.0001). The mean Tegner activity scale was 4.23 after injury and it improved to 7.52 after operation (p<0.0001)) which was a reasonable comparison to the pre- injury score of 8.0. One patient had a mild valgus deformity with no functional disturbance. No other growth related abnormalities including limb length discrepancy were noted. There has been one re-rupture but all others had good or excellent outcome. This is one of the largest series reporting the long term results of ACL reconstruction in very young children. Most other studies include children up to the age of 16. Based on our results we can conclude that transphyseal ACL reconstruction modified for very young patients is a safe procedure

Purpose of Study. In this review, we present the data of one of the largest non-designer, mid- to long-term follow-ups of the AGC carried out by surgeons of differing grades and sub-specialty. Summary of methods and Results. We present a total of 1538 AGC knees during a 15 year period, of which 902 were followed up by postal or telephone questionnaire focused on Oxford Knee Scores, Visual analogues of function and pain and survival analyses performed. 85.7% of patients had an Oxford knee score of between 0 and 40, with 71.2% scoring between 0 - 30. 65.6% of patients responded with a Visual Analogue Score (VAS) of 0 or 1 at rest (minimum pain = 0) and 53.9% reporting VA scores of 0 or 1 while walking. 87.5% of patients reported Excellent or good functional reports at final follow up and 90.3% reporting excellent or good pain control compared to per-operative levels. There is a survivorship of 95.88% at 15years. This large cohort and multi-surgeon & multi-experience level trial reproduces the excellent results as demonstrated by the designer centre (Ritter et al.) and is better than most others in the literature. Mid to long term outcome shows excellent function and analgesia. Complication rates are low and the necessity for revision remains low. Conclusion. In the hands of most orthopaedic surgeons, the AGC knee continues to deliver reproducible and satisfactory results and have good survivorship

We reviewed 5086 patients with a mean age of 30 years (9 to 69) undergoing primary reconstruction of the anterior cruciate ligament (ACL) in order to determine the incidence of secondary pathology with respect to the time between injury and reconstruction. There was an increasing incidence of medial meniscal tears and chondral damage, but not lateral meniscal tears, with increasing intervals before surgery. The chances of requiring medial meniscal surgery was increased by a factor of two if ACL reconstruction was delayed more than five months, and increased by a factor of six if surgery was delayed by > 12 months. The effect of delaying surgery on medial meniscal injury was also pronounced in the patients aged < 17 years, where a delay of five to 12 months doubled the odds of medial meniscal surgery (odds ratio (OR) 2.0, p = 0.001) and a delay of > 12 months quadrupled the odds (OR 4.3, p = 0.001). Increasing age was associated with a greater odds of chondral damage (OR 4.6, p = 0.001) and medial meniscal injury (OR 2.9, p = 0.001), but not lateral meniscal injury. The gender split (3251 men, 1835 women) revealed that males had a greater incidence of both lateral (34% (n = 1114) vs 20% (n = 364), p = 0.001) and medial meniscal tears (28% (n = 924) vs 25% (n = 457), p = 0.006), but not chondral damage (35% (n = 1152) vs 36% (n = 665), p = 0.565). We conclude that ideally, and particularly in younger patients, ACL reconstruction should not be delayed more than five months from injury.

Cite this article: Bone Joint J 2013;95-B:59–64.

Abstract. Introduction. The Syn-VAR RCT is the first of its kind comparing hamstrings autograft v synthetic neoligament for MPFL reconstruction. Our aim is to evaluate short and long term patient related outcomes measures (PROMs) following synthetic / autologous MPFL reconstruction in a heterogenous cohort of patients with recurrent patellar instability. Method. 20 patients meeting inclusion criteria were recruited and randomised. Standardised surgery was performed by a single surgeon in Altnagelvin Hospital with data collected over 3 years from 2016. Kujala score was the primary outcome measure with data captured preoperatively and 12 weeks/2 years postoperatively. Secondary outcomes included four other validated scores and complications including Norwich Patellar Instability, Lysholm, IKDC and Banff. Results. 20 patients with an average age of 19 included 9 females and 11 males. At 12 weeks and 2 years Kujala improvement in the hamstring group was 18 and 32 (both p<0.05) compared to the synthetic group where the increase was 2 and 20 (p<0.05). All secondary score improvements at 2 years were significant (p<0.05) with no difference in any score at all time intervals when comparing both groups (p<0.05). Discussion. Our RCT validates the non-inferiority of synthetic MPFL reconstruction as a treatment for restoring patellar stability in a small heterogenous group with positive long term data and minimal morbidity. With no hamstring harvesting offering a reduction in theatre time with this offers a safe, efficient and viable alternative with reduced morbidity

Abstract. Introduction. Isolated patellofemoral joint(PFJ) osteoarthritis affects approximately 10% of patients aged over 40 years and treatment remains controversial. Our aim was to evaluate long term functional and radiological outcomes following PFJ arthorplasty with the Femoro Patella Vialli (FPV) prosthesis as this evidence is lacking in literature. Methodology. A retrospective review of prospectively collected PROMS in patients undergoing Patellofemoral arthroplasty. Single centre trial. Between 2004 and 2008, 101 FPV patellofemoral arthroplasties were performed in 80 patients with isolated patellofemoral joint osteoarthritis. Data was collected as a part of routine follow-up for up to 6 years and additional long term data was collected at 16 years. Results. At 6 year follow up the mean OKS was 29 and by 16 year follow up it was 26 which was not a statistically significant drop. 22 patients (29 knees) had died, 32 (32%) had been revised, 25 to total knee replacement using primary arthroplasty components. Mean OKS in the revised group was 27 which was not a statistically significant difference when compared to the unrevised group. Mean time to revision was 4 years. The cumulative survival analysis of the FPV implant was 76% at 5 years, 64% at 10 years. Conclusion. Our findings suggest the FPV patellofemoral prosthesis provides good pain relief and clinical outcomes however, the survivorship for this particular implant maybe lower as compared to the available literature. Patient reported outcomes are maintained over the implant life and are no worse once revised implying a staged approach to arthroplasty is reasonable

Aims. The use of high tibial osteotomy (HTO) to delay total knee arthroplasty (TKA) in young patients with osteoarthritis (OA) and constitutional deformity remains debated. The aim of this study was to compare the long-term outcomes of TKA after HTO compared to TKA without HTO, using the time from the index OA surgery as reference (HTO for the study group, TKA for the control group). Methods. This was a case-control study of consecutive patients receiving a posterior-stabilized TKA for OA between 1996 and 2010 with previous HTO. A total of 73 TKAs after HTO with minimum ten years’ follow-up were included. Cases were matched with a TKA without previous HTO for age at the time of the HTO. All revisions were recorded. Kaplan-Meier survivorship analysis was performed using revision of metal component as the endpoint. The Knee Society Score, range of motion, and patient satisfaction were assessed. Results. Mean follow-up was 13 years (SD 3) after TKA in both groups. The 20-year Kaplan-Meier survival estimate was 98.6% in TKA post-HTO group (HTO as timing reference) and 81.4% in control group (TKA as timing reference) (p = 0.030). There was no significant difference in clinical outcomes, radiological outcomes, and complications at the last follow-up. Conclusion. At the same delay from index surgery (HTO or TKA), a strategy of HTO followed by TKA had superior knee survivorship compared to early TKA at long term in young patients. Level of evidence: III. Cite this article: Bone Jt Open 2023;4(2):62–71

Abstract. Introduction. Transforming outpatient services is a key commitment set out in the NHS Long Term Plan, with particular emphasis on digital solutions to reduce outpatient follow-up (FU) by 25%. This study looks at the potential for removing knee arthroscopy FU by providing a bespoke multimedia report for each individual patient, generated using the Synergy™ Surgeon App (Arthrex). Methodology. Single District Hospital using a 3 Phase study. Phase 1 – Assessment of cost and environmental impact of outpatient follow up appointments. Phase 2 – Bench marking of existing pathways and patient experience. Phase 3 – Qualitative assessment of multimedia report feedback of 30 patients. Results. Phase 1 – Impact per year for Trust in released clinician time 135hrs. Cost avoidance £40-£60k. Reduction of the carbon footprint from reduced FU of 3132 KgCo2e2. Phase 2 – Deep dive on 2019 n. 353 procedures. 1206 outpatient appointments required. Average 1.2 post-operative appointments. Phase 3 – 87% of patients who received the e-op report needed no further FU. This compares to only 25% using a traditional post op discussion after surgery. 94% of patients felt the report aided their recovery. Conclusions. Reducing patient FU appointments is crucial to the future of the NHS. Achieving this whilst simultaneously improving the quality of patient communication is achievable as this study has demonstrated. The potential scalability of this project to be applied other arthroscopic procedures is enormous. The study has demonstrated patients are comfortable with modern technology and feel it enhances their understanding whilst decreasing the need for routine post-op FU

Abstract. Introduction. There is a longstanding presumed association between obesity, complications, and revision surgery in primary knee arthroplasty. This has more recently been called into question, particularly in centres where a high volume of arthroplasty is performed. We investigated the correlation between Body Mass Index (BMI), mortality, and revision surgery. Method. This was a cohort study of at least 10 years following primary knee arthroplasty from a single high volume arthroplasty unit. Mortality and revision rates were collected from all patients who underwent primary knee arthroplasty between 2009 and 2010. Kaplan Meier analysis was performed. Results. There were 1161 female and 948 male patients with a mean age of 69 (21 to 97). All cause survivorship excluding mortality was 97.2% up to 13yrs with a minimum of 10 years. The revision rate in this series was 2.8% with no significant difference in revision rates after 10 year between patients with BMI above and below 40 (p=0.438). There was no significant difference in 10-year mortality between patients above and below a BMI of 40 (p=0.238). Conclusion. This study shows no significant difference in the long term survival of total knee replacement between patients with normal and high BMI. Careful consideration should be given before rationing surgery based on BMI alone

Abstract. Introduction. Fractures of the articular surface of the patella or the lateral femoral condyle usually occur following acute dislocation of the patella. This study looked at the radiological and functional outcomes of fixation of osteochondral fractures. Methods. Twenty-nine patients (18 male, 11 female) sustained osteochondral fractures of the knee following patellar dislocation. All patients had detailed radiographic imaging and MRI scan of the knee preoperatively. An arthroscopic assessment was done, followed by fixation using bio-absorbable pins or headless screws either arthroscopically or mini-open arthrotomy. VMO plication or MPFL repair were done if necessary. MRI scan was done at follow-up to assess for healing of the fixed fragment prior to patient discharge. Results. The mean age of the patients was 21 yrs (9–74), 11 had osteochondral fracture of the patella (38%), while 18 were from the lateral femoral condyle (62%). 13 patients needed additional VMO plication. Mean follow up period was 7.7 years (1 to 12 years). As per Tegner activity scale, all patients returned to their pre-injury activity level (Mean score 7) and sports. None of the patients had a further episode of patellar dislocation. Mean postoperative IKDC score was 86.5 (SD 17.3), Kujala was 91.1(SD 15.5) and Tegner- lysholm was 88.7 (SD 14.4). All patients had statistically significant (p < 0.05) improvement. Post-operative MRI scan showed satisfactory union in all cases (100%). Conclusion. It is extremely important to identify this group of injury and treat them early to have satisfactory knee function and avoid long term complications of arthritis

Abstract. Aims. The primary aim of this study was to evaluate the outcomes of fungal knee periprosthetic joint infection following knee arthroplasty. The secondary aim was to evaluate risk factors for acquiring a fungal PJI. Patients and Methods. This was a retrospective analysis of patients presenting with a confirmed fungal PJI of the knee in two tertiary centres. There were a total of 45 cases. Isolated fungal infections along with mixed bacterial and fungal infections were included. Mean follow up was 40 months (range 3–118). Results. The mean age at presentation was 69 years (range 46 to 87) and mean BMI was 31 kg/m2 (range 20 to 44). The median number of procedures that patients had on the affected limb from the index primary arthroplasty procedure was 6 (range 2–17). The median procedure number at which a fungal infection was identified was 5 (range 2–10). A history of prolonged antibiotic therapy (above 6 months total) was present in 37 patients (88%). During the study period 22 patients were infection free, 14 treated with lifelong suppression, 7 had above knee amputations and 6 had died. Overall infection cure rate was 49%. Conclusions. Patients with fungal PJI are generally poor hosts with multiple co-morbidities, long term exposure to antibiotics and high rates of open wounds and sinuses. The poor outcome associated with fungal PJI relative to bacterial PJI should be shared with patients in order to manage the expectations of this complex cohort

Abstract. Introduction. The number of total knee replacements (TKRs) performed continues to increase and is marked in patients under the age of 60. Increased number of younger patients raises concerns about potentially increased rates of implant failure or revision. Previous studies used small cohorts with only short to medium term follow-up. This study is the largest of its kind reporting long term outcomes and clinical survivorship of patients 50 years or less undergoing TKR. Methods. This is a retrospective cohort study using data from the Scottish Arthroplasty Project. A total of 3727 patients 50 years or less undergoing TKR between 2000 and 2019. Data was also collected for the same time period on patients aged 50–79 years undergoing TKR for comparison. Results. Mean age for under 50 years cohort at initial TKR was 45.4 years. Primary reason for TKR was osteoarthritis (3025 cases) and 321 revisions were performed. The primary reason for revision was aseptic loosening (206 cases), or infection (18 cases). Average time to revision was 5.5 years. In the 50–79 years cohort, average age was 67.5 years. Primary reason for TKR was osteoarthritis (87776 cases) and 2997 revisions were performed. Principle reason for revision was infection (256 cases), or aseptic loosening (2042 cases). Average time to revision was 4 years. Conclusion. This study suggests long-term outcome of patients aged 50 years or less undergoing TKR remain promising. Patients should be aware of relatively higher rates of aseptic loosening requiring revision in patients aged 50 years or less undergoing TKR

Abstract. Introduction. The NHS long term plan endorses ‘personalised’, ‘digitally enabled’, ‘out of hospital’ care. Multiagency guidance (CPOC(2021)/NICE(2021)/GIRFT(2021)/NHSX(2021)) advocates an integrated ‘pathway’ approach to information sharing, shared-decision making and patient support. Digital solutions are the vehicle to deliver these agendas. Methods. In 2018 we developed a digital joint pathway (DJP) spanning the surgical care pathway (prehabilitation to rehabilitation) using the GoWellHealth platform. Patients listed for joint replacement are offered the DJP as routine care. Activity and engagement are monitored using the DJP data library. We sought to evidence our DJP by assessing patient engagement, experience and outcomes (OKS/EQ5D/Readmission). Results. Engagement. Consecutive cohort of the first 1195 patients registered. Activation rates were >85% and >70% viewed content within the DJP (median=15 access/pt; mean=83 minutes on DJP/pt). Engagement was similar irrespective of age and gender (p=NS). Older patients preferred to access via a computer. Experience. Qualitative interviews (n=14) demonstrated patients felt the DJP impacted positively on their health behaviours and contributed to their recovery. They spoke positively about the use of technology and the accessibility of the DJP. Outcomes. Comparison of patients on the DJP versus those not on the DJP using adjusted regression models demonstrated improved EQ5D=0.070 (95%CI=0.004-0.135,p=0.04), OKS=5.0 (95%CI=2.2-7.8,p<0.001) and readmission rates (3.6% versus 5.6%,p<0.01) for DJP patients. Conclusions. A DJP model for information delivery and patient support, across the entirety of the surgical pathway, is feasible and demonstrates high levels of patient engagement, experience and improved patient outcomes

Aims. Debate continues regarding the optimum management of periprosthetic distal femoral fractures (PDFFs). This study aims to determine which operative treatment is associated with the lowest perioperative morbidity and mortality when treating low (Su type II and III) PDFFs comparing lateral locking plate fixation (LLP-ORIF) or distal femoral arthroplasty (DFA). Methods. This was a retrospective cohort study of 60 consecutive unilateral (PDFFs) of Su types II (40/60) and III (20/60) in patients aged ≥ 60 years: 33 underwent LLP-ORIF (mean age 81.3 years (SD 10.5), BMI 26.7 (SD 5.5); 29/33 female); and 27 underwent DFA (mean age 78.8 years (SD 8.3); BMI 26.7 (SD 6.6); 19/27 female). The primary outcome measure was reoperation. Secondary outcomes included perioperative complications, calculated blood loss, transfusion requirements, functional mobility status, length of acute hospital stay, discharge destination and mortality. Kaplan-Meier survival analysis was performed. Cox multivariate regression analysis was performed to identify risk factors for reoperation after LLP-ORIF. Results. Follow-up was at mean 3.8 years (1.0 to 10.4). One-year mortality was 13% (8/60). Reoperation was more common following LLP-ORIF: 7/33 versus 0/27 (p = 0.008). Five-year survival for reoperation was significantly better following DFA; 100% compared to 70.8% (95% confidence interval (CI) 51.8% to 89.8%, p = 0.006). There was no difference for the endpoint mechanical failure (including radiological loosening); ORIF 74.5% (56.3 to 92.7), and DFA 78.2% (52.3 to 100, p = 0.182). Reoperation following LLP-ORIF was independently associated with medial comminution; hazard ratio (HR) 10.7 (1.45 to 79.5, p = 0.020). Anatomical reduction was protective against reoperation; HR 0.11 (0.013 to 0.96, p = 0.046). When inadequately fixed fractures were excluded, there was no difference in five-year survival for either reoperation (p = 0.156) or mechanical failure (p = 0.453). Conclusion. Absolute reoperation rates are higher following LLP fixation of low PDFFs compared to DFA. Where LLP-ORIF was well performed with augmentation of medial comminution, there was no difference in survival compared to DFA. Though necessary in very low fractures, DFA should be used with caution in patients with greater life expectancies due to the risk of longer term aseptic loosening. Cite this article: Bone Joint J 2021;103-B(4):635–643

Introduction. One of the main considerations in the revision TKR setting is deciding on the level of constraint to be utilized once the bone defects have been reconstructed. There is a fear that employing a maximally constrained insert could compromise long term results. We report on a consecutive series of full tibial and femoral component revisions all treated with a maximally conforming insert and followed for a minimum of 5 years. Materials and Methods. The study group consisted of 76 consecutive revision TKR in 76 patients where both the femur and the tibia were revised. 4 patients died and 6 were lost to follow up. Final cohort had an average age of 70 years, average BMI of 31 and there were 39 males in the group. Average time to revision was 7 years (range 1–10 years) and the reasons for revision included infection in 28, aseptic loosening 26, osteolysis and poly wear in 9 and 13 other. All were treated with the same revision system and an identical maximally conforming tibial rotating platform insert and followed for an average of 7 years (range 5–14 years). Results. one patient required additional surgery during the study period for a patella fracture. There were no manipulations. Average Knee Society Scores increased from an average of 55 to 89 at final follow up. No implants were loose or at risk of loosening and no knee sustained any mechanical complications related to the insert. Conclusion. Despite fears to the contrary, we did not identify any issues in using a maximally constrained insert in this consecutive group of revision total knee patients. It is unclear if the fact that these inserts were of a rotating platform design is important. In this group of revision TKRs, using the maximal level of constraint did not appear to negatively influence outcome at mid-term follow up

Introduction. The ideal type of total knee arthroplasty (TKA) prosthesis remains a debatable topic with many different options available. Uncemented TKA has been a viable option due to its decreased operating room (OR) time but also because of its proposed improved long term fixation. Unfortunately, in the past uncemented TKA was associated with increased blood loss. Surgical technique and perioperative treatments have changed since these original studies and tranexamic acid (TXA) has become the gold standard for TKA blood loss management. The objective of this study was to evaluate if there was a difference in hemoglobin and hematocrit change, along with blood loss volume during surgery between cemented and cementless TKA when modern blood loss techniques are utilized. Methods. We retrospectively reviewed data from TKAs performed by three high volume surgeons between 2016 and 2019. We excluded bilateral TKA, revisions, hardware removal intraoperatively and other indications for TKA than primary OA. Power analysis determined 85 patients in both the cementless and cemented TKA groups. Patients were matched 1:1 for age, sex, BMI and surgeon. Use of TXA, intraoperative blood loss, differences in hemoglobin and hematocrit pre- and postoperatively days one, two, and three were recorded. Continuous variables were analyzed using T-tests and categorical variables were evaluated using Chi-squared tests. Results. No significant difference was observed between the cementless and cemented groups for hemoglobin (p=0.214), hematocrit (p=0.164), or intraoperative blood loss volume (p=0.343). A trend towards significantly shorter OR time was seen in the cementless group (p = 0.058). Conclusion. With modern TKA surgery, including the use of TXA, there is no difference in perioperative blood loss between cemented and cementless TKA. Unlike previous studies, the use of modern blood loss salvage techniques in conjunction with cementless TKA fixation, does not result in more blood loss during the perioperative period

Aim. To evaluate safety and efficacy of performing a total knee arthroplasty (TKA) on patients receiving continuous Warfarin therapy. Methods. We identified 24 consecutive patients receiving long term warfarin therapy who underwent total knee arthroplasty between 2006 and 2008. As a control, we collected the same data from a group of age and sex matched patients not on warfarin. Primary observations were changes in haemoglobin, transfusion rates and complications. Secondary observations were fluctuations in the INR and post operative range of motion (ROM). All procedures were performed by the senior author in a single centre using the same TKA technique. Results. There was no significant difference between the warfarinised and non warfarinised groups in preoperative or postoperative haemoglobin. After unilateral TKA 38% of non warfarinised patients and 24% of warfarinised patients required a blood transfusion. Both the warfarin and non warfarin groups had a bilateral TKA transfusion rate of 67%. In the warfarin group the mean preoperative INR was 2.2 (SD=0.46; range 1.0 to 3.0) and mean postoperative INR was 2.6 (SD=0.8; range 1.5 to 5.0). There were no surgical delays due to a high INR level. The mean change in INR during the perioperative phase was minimal (mean 0.4; SD=0.7). In the warfarin group the mean flexion range of motion was 116° preoperatively, 88° at 5 days, 107° at 6 weeks and 117° at 12 months after surgery. There was no significant ROM difference between the warfarin and non warfarin groups. There were no post operative bleeding complications. Conclusions. Current American College of Chest Physicians (ACCP) guidelines recommend bridging therapy for high risk patients receiving oral anticoagulation undergoing major orthopaedic procedures. We have shown that a safe alternative is to continue the steady state warfarin perioperatively in patients on long term warfarin therapy requiring TKA

Aims

To assess the incidence of radiological lateral osteoarthritis (OA) at 15 years after medial unicompartmental knee arthroplasty (UKA) and assess the relationship of lateral OA with symptoms and patient characteristics.

Aims

The aim of this study was to compare the migration of the femoral component, five years postoperatively, between patients with a highly cross-linked polyethylene (HXLPE) insert and those with a conventional polyethylene (PE) insert in an uncemented Triathlon fixed insert cruciate-retaining total knee arthroplasty (TKA). Secondary aims included clinical outcomes and patient-reported outcome measures (PROMs). We have previously reported the migration and outcome of the tibial components in these patients.

Objectives. The objective of this study was to compare the early migration characteristics and functional outcome of the Triathlon cemented knee prosthesis with its predecessor, the Duracon cemented knee prosthesis (both Stryker). Methods. A total 60 patients were prospectively randomised and tibial component migration was measured by radiostereometric analysis (RSA) at three months, one year and two years; clinical outcome was measured by the American Knee Society score and the Knee Osteoarthritis and Injury Outcome Score. Results. There were no statistically significant differences in rotation or translation around or along the three coordinal axes, or in the maximum total point motion (MTPM) during the two-year follow-up. Conclusions. The Triathlon cemented knee prosthesis has similar early stability and is likely to perform at least as well as the Duracon cemented knee prosthesis over the longer term