Survivorship of 500 Cementless Total Knee Arthroplasties in Patients Under 55 Years of Age.

BACKGROUND: With respect to survivorship following total knee arthroplasty (TKA), joint registries consistently demonstrate higher revision rates for both genders in those aged less than 55 years. The present study analyzed the survivorship of 500 cementless TKAs performed in this age group in a high-volume primary joint unit where cementless TKA has traditionally been used for the majority of patients. METHODS: This was a retrospective review of 500 consecutive TKAs performed in patients aged less than 55 years between March 1994 and April 2017. The primary outcome measures for the study were survivorship and all-cause revisions. Secondary outcome measures included nonrevision procedures, clinical, functional, and radiological outcomes. RESULTS: An all-cause survival rate of 98.4% and an aseptic survival rate of 99.2% at a median time of 10.7 years (interquartile range 7.3-14.9, range 0.2-27.7) were found. Four patents were revised for infection, 2 for stiffness, 1 for aseptic loosening of the tibial component, and 1 for a patella that was resurfaced for anterior knee pain. Thirty four patients (6.8%) had a nonrevision procedure with manipulation under anesthetic accounting for 27. On a multivariate analysis, preoperative range of motion and female gender were negatively associated with postoperative range of motion (P < .001 and P = .003, respectively). Sixty seven patients (17.3%) had radioluscent lines and on a multivariate analysis, there were no significant predictors of radiolucent lines. CONCLUSION: Cementless TKA in the young patient can achieve excellent clinical and functional outcomes. At a median of 10.7 years, aseptic revision rates are exceptionally low at 0.8% for the entire cohort.

Is Cementless Total Knee Arthroplasty Safe in Women Over 75 Y of Age?

BACKGROUND: Cementless total knee arthroplasty (TKA) is the subject of renewed interest. Previous concerns about survivorship have been addressed and there is an appeal in terms of biological fixation and surgical efficiency. However, even surgeon advocates have concerns about the risk of marked subsidence when using this technology in older patients at risk for osteoporosis. METHODS: This was a retrospective analysis of 1,000 consecutive fully cementless mobile bearing TKAs performed at a single institution on women over 75 years of age who had postoperative and 1-year x-rays. The primary outcome was the incidence of subsidence. RESULTS: There were three asymptomatic cases with definite subsidence and change in alignment. In a fourth symptomatic case, the femoral component subsided into varus and the tibia into valgus, thus maintaining alignment which facilitated nonoperative treatment in a 92-year-old. Overall, at 1 year, there were two- liner revisions for infection without recurrence. Five patients had further surgery, of which three were washouts and two were for periprosthetic fractures sustained postoperatively within 1 year. Seven patients had further anesthesia, of which five were manipulations and two were nonrecurrent closed reductions for spinouts. CONCLUSION: Cementless TKA did not have a high risk of subsidence in this at-risk population. In the hands of experienced surgeons, these procedures can be used safely irrespective of bone quality.

Decision regret after primary hip and knee replacement surgery.

BACKGROUND: Decision regret (DR) is a recognised patient centered outcome measure following a therapeutic intervention. This study aimed to measure DR following primary total hip and knee arthroplasty (THA/TKA), to assess for differences between these patients and explore possible contributory factors. METHOD: DR was measured using the DR scale in a group of THA and TKA patients, between February 2017 and December 2018, who had made a decision to have joint replacement surgery within the previous year and were able to reflect on their outcomes. RESULTS: On analysis a significantly greater proportion of TKA patients reported moderate or severe (Mod/Sev) DR [17.1% (56/328)] compared to THA patients [4.8% (18/376)]. Conversely, a significantly reduced proportion of TKA patients reported having No DR [42.1% (138/328)] compared to THA patients [66.7% (251/376)]. On multivariate logistic regression analysis joint replacement type (TKA/THA) and change in Oxford score were significant predictors of DR with gender, age, BMI and ASA grade not significantly associated. TKA patients were more than twice as likely to have Mod/Sev DR compared THA patients (Odds Ratio = 2.33 (95% CI 1.24-4.39)). Patients with poorer improvements in pain and function 1-year post-operatively (measured by Oxford scores) reported greater levels of DR. CONCLUSION: TKA patients were significantly more likely to report greater levels of DR 1-year following surgery compared to THA patients. For both TKA and THA patients, greater levels of DR were associated with poorer Oxford scores. The use of decision aids to reduce post-operative DR in joint replacement patients should be examined especially for knee replacement patients.

Risk Factors for Significant Radiolucent Line Development in a Fully Coated Hydroxyapatite Stem.

BACKGROUND: The risk factors for and clinical impact of radiolucent lines (RLLs) in cementless total hip arthroplasty remain contentious. The aim of this work was to describe a method of classification that has clinical significance and to identify risk factors. METHODS: A cohort of 288 subjects with unrevised Corail stems (DePuy Synthes, Warsaw, IN) were reviewed with radiographs and Oxford Hip Scores at 10 years. Based on clinical experience, three groups were defined; those with no RLLs (NoRLLs), those considered to have benign RLLs (BenRLLs), and those considered to have significant RLLs (SigRLLs). SigRLLs were then compared to BenRLLs and NoRLLs to determine the validity of this classification. RESULTS: One hundred and nine (37.8%) had NoRLLs, 111 (38.5%) had BenRLLs, and 68 (23.6%) had SigRLLs. No significant difference apart from gender was noted between the occurrence of BenRLLs and NoRLLs after multinomial regression analysis, consequently the NoRLLs and BenRLLs groups were combined (NoSigRLLs) and compared to SigRLLs. Non-cross-linked polyethylene (odds ratio = 4.6, P < .001), collarless stem design (odds ratio = 9.4, P < .001), undersizing (odds ratio = 1.2, P = .028), and male sex (odds ratio = 2.1, P = .008) were risk factors for SigRLLs. Regression analysis also revealed that increasing age at operation decreased the likelihood of SigRLLs (P < .001). Patients with SigRLLs had significantly higher pain scores (P = .005) although overall Oxford Hip Scores were not significantly different (P = .364). CONCLUSION: The definition of SigRLLs proposed in this study was significantly associated with that of non-cross-linked polyethylene, absence of a collar, undersizing, and higher pain scores.

A Prospective Randomized Study Comparing Postoperative Pain, Biological Fixation, and Clinical Outcomes Between Two Uncemented Rotating Platform Tibial Tray Designs.

BACKGROUND: With the demand for arthroplasty increasing worldwide year on year, there is a drive to improve prosthesis longevity. Biological fixation from cementless implants has been one method of trying to achieve this. We hypothesized that the addition of a hydroxyapatite (HA) coating and 4 pegs to a porous-coated tibial tray would provide a reduction in time to implant osseointegration, allowing for normal physiological stress transfer, thus improving early postoperative pain and rehabilitation as well as the elimination of radiolucent lines (RLLs). METHODS: A prospective, randomized controlled single-blinded study was undertaken, comparing postoperative pain, radiographic evidence of biological fixation, and clinical outcomes between patients undergoing primary total knee arthroplasty with either LCS Complete POROCOAT (porous coating only) or LCS Complete DUOFIX (porous coating plus HA and pegs) knee systems (DePuy Synthes, Warsaw, IN). In total, 197 patients (205 knees) were recruited into the study between November 2006 and November 2008 and have been followed for up to 10 years. RESULTS: There were no clinically significant differences in pain or patient-reported outcome measures when comparing the 2 designs but the tibial tray with pegs and HA showed fewer RLLs at all time points. There was no correlation between RLLs and pain and no instances of loosening or osteolysis in either group. There was 1 revision for infection in the porous coating only group. CONCLUSION: The tray design with HA and additional fixation pegs did not confer any benefit in terms of reduced early postoperative pain or improved patient-reported outcomes, although it did result in significantly fewer RLLs. Both implants demonstrated excellent survivorship. With a cementless porous-coated tibial component, nonprogressive RLLs should be considered normal.

Are There Gender-Specific Errors in Restoration of Hip Biomechanics That Affect Outcome Following Total Hip Arthroplasty?

BACKGROUND: There are morphologic differences between males and females, which are currently underappreciated during total hip arthroplasty. We sought to assess whether these differences affected surgical process and subsequent outcome. METHODS: A total of 123 patients (75 females, 48 males) had preoperative and 1-year Oxford Hip Score (OHS) and pain scores recorded. Acetabular height and offset, femoral height and offset, and acetabular floor depth were measured on preoperative and postoperative X-rays and then compared to their normal opposite hip. Discrepancies between the replaced and normal hip X-ray measurements were then correlated with changes (the delta gain) in preoperative and 1-year postoperative OHS and pain scores. RESULTS: Postoperatively, females had significantly greater femoral height discrepancy (P = .023) which meant they were lengthened. This led to a reduced delta gain in OHS and pain score at 1 year. Males lost more acetabular offset than females (P = .002), leading to a medialized acetabular center and subsequently reduced delta gain in pain score at 1 year (P = .017). CONCLUSION: Females have a smaller femur leading to a bias toward a conservative (higher) neck cut compared with males and potential for femoral lengthening. Males have a greater acetabular floor depth compared with females and thus reaming to the true floor results in greater loss of acetabular offset. In this series, both scenarios led to reduced improvement in OHS and/or pain scores at 1 year.

Total Knee Arthroplasty in Severe Valgus Deformity Using a Modified Technique-A 10-Year Follow-Up Study.

BACKGROUND: Valgus knee deformity accounts for only 10% of total knee arthroplasties (TKAs), but is frequently considered the most challenging to manage. This study provides a 10-year follow-up on a previously reported series of severe valgus knees performed using an unconstrained mobile-bearing TKA with a modified technique to validate this technique. METHODS: A consecutive series of 275 predominantly cementless TKAs in 262 patients were performed for severe valgus (≥10°) deformity and prospectively followed to 10 years. Patient-reported outcome measures included the Oxford Knee Score, American Knee Society Score, Bartlett Patellar Score, and the Short Form 12 questionnaire. RESULTS: Average valgus deformity was reduced from 15.6° to 3.8° (P < .001). At a mean follow-up of 10.4 years (range, 9.5-14.1), 90 (34.4%) patients had died. Of the reviewed survivors, the mean Oxford Knee Score was 27.8 ± 9.8, with an American Knee Society clinical score of 85.6 ± 17.0 and a functional score of 65.1 ± 20.4, with 78% of patients reporting good to excellent results. To date, there has been 1 (0.36%) revision and 13 (4.73%) reoperations. Kaplan-Meier implant survival was 99.6% at 10 years. CONCLUSION: Despite its challenging nature, the valgus knee is associated with excellent survivorship and satisfactory long-term results using this modified technique. LEVEL OF EVIDENCE: Level IV.

Seventeen to Twenty Years of Follow-Up of the Low Contact Stress Rotating-Platform Total Knee Arthroplasty With a Cementless Tibia in All Cases.

BACKGROUND: Total knee arthroplasty designs can be categorized by bearing design and fixation method. The mobile-bearing concept was developed with the aim of increasing longevity and improving function by reduced polyethylene wear and closer replication of physiological knee motion. Cementless fixation has the goal of achieving a long-lasting "biological" fixation between prosthesis and bone. METHODS: Prospective analysis of the survivorship and patient-reported functional outcomes of a series of 500 low contact stress rotating-platform mobile-bearing total knee arthroplasties with a cementless tibial component with a minimum 17-year follow-up. RESULTS: Five hundred primary total knee arthroplasties were conducted in 467 patients. Mean follow-up was 18.1 (17.0-21.8) years and 141 (28.2%) knees were alive and available for review. Using revision for any cause as the end point, cumulative survivorship was 97.4%. Thirteen knees required revision: 3 for deep infection, 3 bearing only revisions for spinout, 3 for tibial tray subsidence, 2 secondary patella resurfacings, 1 aseptic loosening, and 1 for suspected aseptic loosening that was found to be well fixed. Mean American Knee Society Scores were 83 (evaluation) and 48 (function), Mean Oxford Knee Score was 32.1, and the mean Bartlett Patellar Score was 21.6. CONCLUSION: This series demonstrates excellent survivorship and acceptable patient-reported functional outcome scores of a mobile-bearing total knee arthroplasty with a cementless tibial tray at minimum 17-year follow-up.

A prospective evaluation of a largely cementless total knee arthroplasty cohort without patellar resurfacing: 10-year outcomes and survivorship.

BACKGROUND: The theoretical benefits of a mobile bearing design in Total Knee Arthroplasty (TKA) include increased articular surface conformity with a reduction in both polyethylene wear and implant interface shear. However, to date these theoretical advantages have not been translated into published evidence of superior survivorship. This paper presents the results of a prospective, non-comparative study evaluating the performance of the mobile bearing Low Contact Stress LCS Complete Rotating Platform TKA in a largely cementless cohort without patellar resurfacing. METHODS: 237 consecutive patients (240 knees) undergoing primary TKA were prospectively recruited. All received the LCS Complete Rotating Platform TKA (DePuy International, Leeds, UK). Clinical and radiographic assessments were performed at 3, 12, 60 and 120 months post-operatively. Radiographic evaluation was performed by an independent external surgeon. RESULTS: The mean age was 70.3 years. 77.5% of cases were cementless. Radiographic assessment suggested excellent femoral component fixation. 22 tibial radiolucent lines (RLLs) > 1 mm were observed in 12 knees. No RLLs were progressive. There have been two revisions; one for late infection and one for aseptic loosening. No patients underwent secondary patellar resurfacing. The cumulative implant survivorship, using component revision for any reason as the endpoint, was 98.9% (95% CI, 95.6 to 99.7%) at 10 years. CONCLUSIONS: The excellent survivorship at a minimum 10-year follow-up supports the use of uncemented porous coated fixation without patellar resurfacing with the non-posterior stabilized LCS Complete Rotating Platform TKA.

Spinout/Dislocation in Mobile-Bearing Total Knee Arthroplasty: A Report of 26 Cases.

BACKGROUND: Excellent medium-term to long-term results for function and survivorship have been shown with mobile-bearing (MB) total knee arthroplasty (TKA). One of the key arguments against its use is the risk of "spinout" or dislocation of the MB. The aim of this study is to discuss the etiology, prevention, incidence, management, and outcome of spinout. METHODS: Between October 1993 and February 2016, 8373 consecutive primary MB TKAs were performed irrespective of preoperative deformity. Before 2001, soft-tissue knee balancing was achieved by release of collateral ligaments and all spinouts were treated by open reduction. Thereafter, soft-tissue balancing was achieved without ligament release and with the use of a higher conformity MB and all spinouts were reduced closed, giving 2 comparative cohorts. RESULTS: Twenty-six spinouts occurred in 8373 (0.31%) patients. In the first cohort up until May 2001, there were 14 spinouts of 2379 (0.58%) cases. There were 12 in cohort 2, in those patients having surgery after May 2001, thus giving an incidence of 12 of 5994 (0.2%), which was significantly lower than in cohort 1 (P < .01). Spinout was associated with the valgus knee (P < .01) and most (73%) occurred within the first 6 months. There was 1 arthrodesis in cohort 1 and 1 both-component revision in cohort 2. CONCLUSION: The etiology of spinout is flexion gap instability. It can normally be reduced closed with recurrence being uncommon. Focus on soft-tissue balance necessary with an MB TKA can reduce the incidence of revision for instability as compared to a fixed-bearing TKA. Therefore, the risk of spinout should not be used as an argument against the MB TKA.

Postdischarge Unscheduled Care Burden After Lower Limb Arthroplasty.

BACKGROUND: In contrast to postdischarge arthroplasty readmission rates, the unscheduled reattendance burden to primary care is under-reported. Understanding reasons for reattendance would allow for implementation of strategies to reduce this burden. The present study aims to quantify the out-of-hours (OOH) general practitioner and emergency department (ED) service reattendance burden and readmission rate after primary total hip arthroplasty and total knee arthroplasty, with estimation of the associated costs. METHODS: This is a prospective consecutive cohort study. A prospective audit of all total hip arthroplasty and total knee arthroplasty patients in 2016 in a single high-volume UK arthroplasty unit was performed. Incidence and reasons for reattendance to OOH and ED service, as well as readmission rates, at both 30 and 90 days following discharge are reported. A multivariate analysis was performed to determine patient characteristics, which results in increased reattendance and readmission rates. RESULTS: A total of 2351 procedures resulted in 374 attendances of OOH service and 665 to ED with a total estimated cost of £190,000 within 90 days. The readmission rate was 6.8%. Risk factors for reattendance and readmission were increasing age and a prolonged length of stay. The use of a 5-day postdischarge phone call and a dedicated Arthroplasty Care Practitioner favors reduced reattendances but not the readmission rate, with the additional benefit of being cost-effective. CONCLUSION: The postdischarge arthroplasty reattendance burden is associated with significant costs, and strategies to reduce this should be developed. Further research is required to assess the effectiveness and cost-effectiveness of multicomponent strategies to reduce reattendance operating at scale.

Acute Kidney Injury After Prophylactic Cefuroxime and Gentamicin in Patients Undergoing Primary Hip and Knee Arthroplasty-A Propensity Score-Matched Study.

BACKGROUND: Perioperative acute kidney injury (AKI) can be associated with lower limb arthroplasty and increases morbidity, length of stay, and mortality. AKI is more prevalent in some antibiotic regimes compared with others. The aim of the present study is to assess the impact of cefuroxime (CEF), with or without gentamicin (±G), on AKI rates. METHODS: A prospective cohort study involving patients undergoing hip or knee arthroplasty was performed, between September 1, 2015 and November 30, 2016. Prophylactic intravenous antibiotics were administered according to local policy. AKI was graded according to the validated Acute Kidney Injury Network criteria based on the changes from baseline serum creatinine values. Propensity score matching was performed to identify risk factors. The local audit department approved the study. Appropriate statistical analyses were performed. RESULTS: A total of 2560 met the inclusion criteria, with a female preponderance (1447/2560; 56.5%). The mean age was 67.5 ± 10.7 years, with males being significantly younger (65.9 ± 10.9 vs 68.7 ± 10.4 years). AKI developed in 32 cases (1.25%). There was no difference in AKI rates between CEF alone and CEF in combination with gentamicin (1.07% vs 1.36%; P = .524). Overall 31/32 cases were Acute Kidney Injury Network stage I. AKI did not affect the length of stay. Postoperative infection rate was 7/2560 (0.27%). There were no incidences of Clostridium difficile-associated diarrhea. Multivariate analysis demonstrated an increased AKI risk with the use of intravenous gentamicin. CONCLUSION: C ± G yields low rates of infection and AKI compared with high-dose penicillin-based regimes. It is a safe and effective choice for lower limb arthroplasty.

Knee Flexion Angle Measurement Using Virtual Assessment Tools: Correct Procedure and Potential Pitfalls.

Virtual patient assessment will inevitably require smartphone technology to remotely measure knee range of motion. We conducted an experiment to analyze the impact of observer position relative to the flexed knee on the perceived angle measured using an electronic application (Dr. Goniometer) for iPhone. Two observers measured the apparent knee flexion angle from 7 different positions at 3 different heights relative to the center of the knee joint. Intraclass correlations were calculated to evaluate the intraobserver and interobserver variability using two-way mixed-effects models. The intraclass correlation for interobserver variability was excellent at 0.804 (95% confidence interval 0.663-0.889). When the observer was greater than 15° from the knee perpendicular, the true angle of knee flexion (90°) was not observed in any of the measurements. This was the case when observed from both proximal (range 95°-121°) and distal (range 92°-108°) directions. Ideally the camera lens should be perpendicular to the long axis of the lower limb in the proximal-distal direction and at the same height. However, if the camera lens is within 15° of the perpendicular, then at 90° of true flexion, the perceived angle will not be greater than 95° in 94% of cases.

A conservative approach to dislocation following total hip arthroplasty: a review of 8606 hips.

PATIENTS AND METHODS: We present the data on 8606 total hip arthroplasty (THA) procedures carried out in 7818 patients through a posterior approach between 1998 and 2017. RESULTS: 218 hips (2.5%) suffered at least 1 dislocation with dislocation rates declining from 6.2% from 1998 to 2002 to 1.5% from 2003 to 2017. Overall, 92 hips (1.06%) required revision surgery but of these, only 5 (0.06%) had a full revision of both components with the remaining 87 requiring intervention only on the acetabular side. None have had a pseudo-arthrosis; none were left dislocated and all remain stable to date. CONCLUSIONS: In patients who have a second dislocation within 3 months of their primary surgery we recommend a spica or long leg cylinder cast to reduce the need for revision surgery. We propose an algorithm to manage instability with less aggressive operative treatment in this often-elderly patient population with the potential for less physiological insult and significant cost savings.

Using a ring to locate femoral head centre in total hip arthroplasty.

AIMS: Traditional methods of determining femoral head centre (FHC) during total hip arthroplasty (THA) rely on measuring the distance from a fixed point on the femur or using a calliper. The aim of this experiment was to investigate how accurately a simple circular ring could locate FHC. METHODS: 144 consecutively available femoral heads (FHs) were collected from patients undergoing THA. Each FH was orientated and mounted on a Sawbone, to create a model of its position on a proximal femur. The ring was applied to the posterior aspect of the FH and a head-centre pin (HCP) was then drilled into the FH and the ring removed, leaving the HCP in place.Each FH was then photographed normal to the axis of the HCP. A MATLAB analysis program then assessed the accuracy of the ring in locating FHC. RESULTS: Mean location accuracy for FHC was 1.77 (range 0.07-5.83) mm with 97.2% within 4 mm and all but 1 within 5 mm. CONCLUSIONS: This ring device located FHC to within 4 mm in 97% of a series of osteoarthritic FHs. This indicates that the posterior aspect of the FH maintains its sphericity late into the osteoarthritic process. Having a simple FHC location device during THA would be of value to control leg length and offset when using the posterior approach.

Femoral nerve compression after migration of bone cement to the groin after hip arthroplasty.

Although often a benign complication of total hip arthroplasty, cement extrusion can cause nerve, vessel, and organ compression. We report the case of a 70-year-old male patient in whom an extruded cement mass migrated anteriorly and compressed the femoral nerve and impinged on the femoral artery producing acute, severe groin pain with neuralgia 9 years postoperatively. Paresthesia of the anterior and medial thigh was found on examination. Radiographic, ultrasound, and computed tomographic studies confirmed a 6 × 1.5-cm mass of bone cement in the right groin compressing the femoral nerve that was removed successfully at surgery. Six months postoperatively, the patient's pain had resolved, but hyperesthesia of the medial thigh remained.

Ten-year outcomes following a cohort of ASR XL total hip arthroplasties.

AIMS: To determine the outcome at 10 years of a cohort of ASR XL total hip arthroplasties (THAs) and reasons for revision. METHODS: Between November 2005 and May 2007, 122 ASR XL THAs were implanted. All patients had a routine review at 6 weeks and 1 year, followed by a review in 2009 because of clinical concern and thereafter annual review up to 10 years with MRI. Review also included functional scores, radiographs, pain scores and blood metal ions. RESULTS: 67 (54.9%) ASR XLs had been revised by 11.1 years. Reasons for revision included pain (89.6%), high levels of cobalt and chromium ions (50.7%) and radiographic or MRI changes (80.6%). All 3 factors were present in 23 (34.3%). Pain at 1 year did not predict revision, but pain at the 2009 review did. At 10 years the revised patients had an average Oxford Hip Score (OHS) of 25.38 (12-42) and the non-revised 23.61 (2-21), the difference was not significant (p = 0.48). 3 patients (4.5%) have had a further revision; 2 for a previously unrevised stem and the other for instability. CONCLUSIONS: Our arthroplasty care practitioner service allowed us to identify increased pain and stop using the ASR XL over 3 years before the implant was recalled. The revised patients had similar functional outcome to those unrevised. Poorly performing implants need to be identified earlier.

Influence of preoperative femoral orientation on radiographic measures of femoral head height in total hip replacement.

BACKGROUND: In total hip arthroplasty the surgeon aims to restore the biomechanics of the joint. Femoral height has the greatest influence on restoring limb length and contributes equally to the restoration of femoral head centre. On X-ray, the level of femoral neck resection is most often referenced off the upper border of lesser trochanter. Less frequently, femoral head centre is referenced from the tip of the greater trochanter. The error in measurement of femoral height resulting from unknown femoral rotation is crucially important and can result in inappropriate surgical planning for implant selection and placement. It is unknown which reference produces lower error. METHODS: A sample of femoral shapes was generated using a femoral statistical shape model. These were placed in a range of orientations in terms of external rotation and flexion, at intervals of 10°. Simulated X-rays were then produced and the distances from the tip of either greater or lesser trochanter to femoral head centre were measured. FINDINGS: Although using greater trochanter as a reference demonstrated greater errors at the extremes, both techniques resulted in errors of 7-8 mm with 20° of both femoral external rotation and flexion. INTERPRETATION: Moderate degrees of femoral external rotation combined with flexion can result in unsatisfactory errors when templating limb length. There should be greater focus and an agreed definition for femoral height. There is a clinical need for a method with a lower error in determining true femoral height and the level of neck resection.

Polyethylene spinout in the Attune® Cruciate-Retaining Rotating-Platform (CR RP) total knee arthroplasty performed with a cruciate-sacrificing and measured-resection technique.

INTRODUCTION: Polyethylene (PE) spinout is a known but uncommon complication when using a mobile-bearing (MB) total knee arthroplasty (TKA) design. Sacrificing the posterior cruciate ligament (PCL) is within the manufacturer's recommendations for the Attune® Cruciate-Retaining Rotating-Platform (CR RP) knee design. AIM: To discuss the potential aetiology and prevention of spinout in the Attune® CR RP knee. METHODS: We used a retrospective radiological review from two centres reporting a higher rate of spinout in the Attune® CR RP knee using a cruciate-sacrificing and measured-resection technique when compared to a gap-balancing technique. Three hundred and thirty-two patients were evaluated over a 3-year period. RESULTS: There were 8 out of 279 (2.86%) cases of spinout in our first cohort of patients using a measured-resection technique. There were 0 out of 53 cases of spinout in our second cohort of patients where a gap-balancing technique was used. One spinout was reduced closed, the other seven were initially revised to a thicker RP insert of the same design. Of these seven, three underwent a further revision TKA and one patient required a knee fusion/arthrodesis. CONCLUSIONS: This study reports a higher incidence of PE spinout in the Attune® CR RP TKA when a measured-resection technique in combination with PCL resection is performed. We recommend a gap-balancing technique with conservative soft-tissue release if the surgeon is planning to sacrifice the PCL in the Attune® CR RP.