Aim. Rifampicin and fluoroquinolone based therapy is generally considered as first-choice targeted oral antimicrobial therapy for staphylococcal prosthetic joint infections (PJI) treated with debridement, antibiotics and implant retention (DAIR). Alternative equally effective antimicrobial strategies are urgently needed due to toxicity and drug-drug interactions that frequently occur with this strategy. Data from recent clinical studies suggests equipoise for other antimicrobial treatment regimens. The objective of the Rifampicin Combination Therapy versus Targeted Antimicrobial Monotherapy in the Oral Antimicrobial Treatment Phase of Staphylococcal Prosthetic Joint Infection (RiCOTTA)-trial is to evaluate whether monotherapy with clindamycin is non-inferior to rifampicin/fluoroquinolone combination therapy in patients with staphylococcal PJI that are treated with DAIR. Method. The RiCOTTA-trial is a multicenter, non-inferiority, open-label, randomized controlled trial evaluating clindamycin versus rifampicin/fluoroquinolone combination therapy in the oral treatment phase in patients with staphylococcal PJI managed with DAIR. The trial is performed in 16 hospitals in the Netherlands. Eligible patients are adults with staphylococcal knee or hip PJI managed by DAIR. Patients are included one to six days before antibiotic treatment is switched from intravenous to oral therapy. Patients with a contraindication for rifampicin, with a megaprosthesis or who receive intravenous antibiotics for more than three weeks after initial debridement are excluded. Primary outcome is treatment success one year after finishing antimicrobial treatment. Success is defined as the absence of: i. Infection related re-surgery, ii. New episode of antibiotic treatment for infection of the index joint after the initial treatment phase of 12 weeks, iii. Ongoing use of antibiotics for the index joint at the end of follow-up, iv. Death. The estimated treatment success of rifampicin combination therapy is 85% and the monotherapy strategy is considered not inferior when the difference in treatment success will be less than 10%. Enrolment of 158 patients per group (316 in total) is needed to confirm non-inferiority of monotherapy with a power of 80%. The trial is currently open for enrolment. The study is approved by the Medical Ethics Committee Leiden, the Hague, Delft, the Netherlands and registered under EU trial number 2022-501620-26-00 in Clinical Trial Information System. Conclusions. Currently, the RiCOTTTA study is the largest randomised clinical trial that compares targeted oral monotherapy with rifampicin combination treatment for staphylococcal PJI. Noninferiority of monotherapy would result in a change in national PJI guidelines and enable clinicians to use a more patient-tailored approach when considering antibiotics for patients during the oral treatment phase of PJI

There has been ongoing debate for many years on the relative merits of routine tourniquet use while performing a total knee replacement. Interestingly there have been many retrospective reviews and opinion articles on the topic, but little in the way of well powered prospective randomised clinical trials. Those that dislike the premise of routine tourniquet use usually cite a list of either very rare complications, or theoretical concerns (nerve damage, muscle function, wound healing issues). Like most debate topics however, the issue is usually a shade of grey, rather than black and white, if the pro/con arguments are evaluated individually. There can be little debate that intraoperative blood loss is less with the use of a tourniquet. This has been demonstrated in multiple studies and is clearly intuitively obvious. Interestingly the overall blood loss (intraop + postop) may however be the same regardless of tourniquet use. Having a dry operative field however is important in achieving adequate cement fixation, and if tourniquet use is not employed, an alternative should be. There is an overwhelming body of literature that supports the understanding that increased OR time directly correlates to increased infection rates in total joint arthroplasty. Proponents of not using a tourniquet will often have alternates to achieving a dry operative field that clearly add time to the procedure – meticulous hemostasis, air delivery systems, etc. This increased OR time may come at the cost of increased infection risk. There is clearly a need for well-designed randomised clinical trials evaluating the practice of routine tourniquet use in TKA. Any trial done however must look critically at factors such as OR time, costs of alternatives, and potential long-term outcome effects

There has been ongoing debate for many years on the relative merits of routine tourniquet use while performing a total knee replacement. Interestingly there have been many retrospective reviews and opinion articles on the topic, but little in the way of well powered prospective randomised clinical trials. Those that dislike the premise of routine tourniquet use usually cite a list of either very rare complications, or theoretical concerns (nerve damage, muscle function, wound healing issues). Like most debate topics, however, the issue is usually a shade of grey, rather than black and white, if the pro/con arguments are evaluated individually. 1. Blood Loss. There can be little debate that intra-operative blood loss is less with the use of a tourniquet. This has been demonstrated in multiple studies and is clearly intuitively obvious. Interestingly the overall blood loss (intra-op + post-op) may, however, be the same regardless of tourniquet use. Having a dry operative field, however, is important in achieving adequate cement fixation, and if tourniquet use is not employed, an alternative should be. 2. OR time. There is an overwhelming body of literature that supports the understanding that increased OR time directly correlates to increased infection rates in total joint arthroplasty. Proponents of not using a tourniquet will often have alternates to achieving a dry operative field that clearly add time to the procedure – meticulous hemostasis, air delivery systems, etc. This increased OR time may come at the cost of increased infection risk. There is clearly a need for well-designed randomised clinical trials evaluating the practice of routine tourniquet use in TKA. Any trial done, however, must look critically at factors such as OR time, costs of alternatives, and potential long-term outcome effects

Resurfacing the patella is performed the majority of the time in the United States and in many regions it is considered standard practice. In many countries, however, the patella is left un-resurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine rather more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective of randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and un-resurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an un-resurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary

Resurfacing the patella is performed the majority of the time in the US and in many regions it is considered standard practice. In many countries, however, the patella is left unresurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine whether more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and unresurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an unresurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary

Durable humeral component fixation in shoulder arthroplasty is necessary to prevent painful aseptic loosening and resultant humeral bone loss. Causes of humeral component loosening include stem design and material, stem length and geometry, ingrowth vs. ongrowth surfaces, quality of bone available for fixation, glenoid polyethylene debris osteolysis, exclusion of articular particulate debris, joint stability, rotator cuff function, and patient activity levels. Fixation of the humeral component may be achieved by cement fixation either partial or complete and press-fit fixation. During the past two decades, uncemented humeral fixation has become more popular, especially with short stems and stemless press fit designs. Cemented humeral component fixation risks difficult and complicated revision surgery, stress shielding of the tuberosities and humeral shaft periprosthetic fractures at the junction of the stiff cemented stem and the remaining humeral shaft. Press fit fixation may minimise these cemented risks but has potential for stem loosening. A randomised clinical trial of 161 patients with cemented vs. press fit anatomic total shoulder replacements found that cemented fixation of the humeral component provided better quality of life, strength, and range of motion than uncemented fixation but longer operative times. Another study found increased humeral osteolysis (43%) associated with glenoid component loosening and polyethylene wear, while stress shielding was seen with well-fixed press fit humeral components. During reverse replacement the biomechanical forces are different on the humeral stem. Stem loosening during reverse replacement may have different factors than anatomic replacement. A systemic review of 41 reverse arthroplasty clinical studies compared the functional outcomes and complications of cemented and uncemented stems in approximately 1800 patients. There was no difference in the risk of stem loosening or revision between cemented and uncemented stems. Uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems during reverse shoulder arthroplasty. Durable humeral component fixation in shoulder arthroplasty is associated with fully cemented stems or well ingrown components that exclude potential synovial debris that may cause osteolysis

Over the past 30 years, cemented, cementless, and hybrid fixation options have been utilised with various total knee arthroplasty (TKA) implant systems. While cemented components are widely used and considered the most reliable method of fixation, historical results may not be applicable to contemporary patients, who are increasingly younger than 65 years of age. Moreover, the literature is not definitive on which method of TKA fixation obtains the best clinical, functional, and radiographic results. A recent Cochrane meta-analysis on roentgen stereophotogrammetric analysis (RSA) included five randomised clinical trials (RCTs) in 297 participants. The authors observed that cemented fixation of tibial components demonstrated smaller displacement in relation to cementless fixation. However, the risk of future aseptic loosening with uncemented fixation was approximately half that of cemented fixation (risk ratio = 0.47, 95% CI 0.24 to 0.92) with a 16% absolute risk difference between groups. Almost all included studies recorded functional measures of Knee Society and Hospital for Special Surgery knee scores, but the authors of each study found no significant difference between the groups. Recently, highly porous metals have become an attractive fixation option in TKA due to their biomechanical properties. In a large RCT of 397 patients, Pulido et al found that uncemented highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with traditional cemented modular tibias. While longer term studies are needed, cementless TKAs may be a durable and reliable alternative with highly porous metals, particularly in younger patients

Tranexamic acid (TXA) is an effective medication to limit blood loss and transfusion requirements in association with contemporary total joint arthroplasty. TXA is in a class of medications termed anti-fibrinolytics due to their action to limit the breakdown of clot that has already been formed. It is useful to note that TXA does not promote the formation of clot, it simply limits the breakdown of already established clot. A recent systematic review and meta-analysis of randomised clinical trials of TXA use in total hip replacement demonstrated: 1) a substantial reduction in the proportion of patients who required transfusion and 2) no increase in DVT or PE. Similarly a recent Cochrane Database systematic review assessed Anti-fibrinolytic Use for Minimizing Perioperative Blood Transfusion and found tranexamic acid to be effective in reducing blood loss during and after surgery and to be free of serious adverse effects. In orthopaedic surgery varying doses have been used over time. A pragmatic dosing approach for Total Knee and Total Hip patients has been used at the Mayo Clinic over the past 16 years: 1 gram IV over 10 minutes prior to incision (delivered at same time as pre-op antibiotics) followed by 1 gram IV over 10 minutes at the time wound closure is initiated. Infusion rates greater than 100 mg/minute have been associated with hypotension and thus the recommendation for 1 gram over 10 minutes. A recent review of 1500 TKA patients at Mayo Clinic revealed a very low prevalence of clinically symptomatic DVT and PE when tranexamic acid was used with 3 different thromboembolic prophylaxis regimens (aspirin and foot pumps; coumadin; low molecular weight heparin). The safety of TXA for patients with coronary stents has not been fully clarified

Total hip arthroplasty (THA) has been cited as one of the most successful surgical procedures performed today. However, as hip surgeons, we desire constantly improving outcomes for THA patients with more favorable complication rates. At the same time, patients desire hip pain relief and return to function with as little interruption of life as possible. The expectation of patients has changed; they have more physical demands for strength and flexibility, and aspire to achieve more in their recreational pursuits. Additionally, health care system constraints require the THA episode of care to become more efficient as the number of procedures increases with time. These factors, over the past fifteen years, have led to a search for improved surgical approaches and peri-operative pain and rehabilitation protocols for primary THA. The orthopaedic community has seen improved pain control, length of stay, and reduction in complications with changes in practice and protocols. However, the choice of surgical approach has provided significant controversy in the orthopaedic literature. In the 2000s, the mini-posterior approach (MPA) was demonstrated as the superior tissue sparing approach. More recently, there has been a suggestion that the direct anterior approach (DAA) leads to less muscle damage, and improved functional outcomes. A recent prospective randomised trial has shown a number of early deficits of the posterior approach when compared to the direct anterior approach. The posterior approach resulted in patients taking an additional 5 days to discontinue a walker, discontinue all gait aids, discontinue narcotics, ascend stairs with a gait aid, and to walk 6 blocks. Patients receiving the posterior approach required more morphine equivalents in the hospital, and had higher VAS pain scores in the hospital than the direct anterior approach. Interestingly, activity monitoring at two weeks post-operatively also favored DAA with posterior approach patients walking 1600 steps less per day than DAA patients. There has been little difference in the radiographic outcomes or complications between approaches in prospective randomised trials. A number of randomised clinical trials have demonstrated that both the direct anterior and posterior approach provided excellent early post-operative recovery with a low complication rate. DAA patients have objectively faster recovery with slightly shorter times to achieve milestones of function, with similar radiographic and clinical outcomes at longer-term outcomes, with a similar complication rate

Over the past 30 years, cemented, cementless, and hybrid fixation options have been utilised with various total knee arthroplasty (TKA) implant systems. While cemented components are widely used and considered the most reliable method of fixation, historical results may not be applicable to contemporary patients, who are increasingly younger than 65 years of age. Moreover, the literature is not definitive on which method of TKA fixation obtains the best clinical, functional, and radiographic results. A recent Cochrane meta-analysis on roentgen stereophotogrammetric analysis (RSA) included five randomised clinical trials (RCTs) in 297 participants. The authors observed that cemented fixation of tibial components demonstrated smaller displacement in relation to cementless fixation. However, the risk of future aseptic loosening with uncemented fixation was approximately half that of cemented fixation (risk ratio = 0.47, 95% CI 0.24 to 0.92) with a 16% absolute risk difference between groups. Almost all included studies recorded functional measures of Knee Society and Hospital for Special Surgery knee scores, but the authors of each study found no significant difference between the groups. Recently, highly porous metals have become an attractive fixation option in TKA due to their biomechanical properties. In a large RCT of 397 patients, Pulido et al found that uncemented highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with traditional cemented modular tibias. While longer-term studies are needed, cementless TKAs may be a durable and reliable alternative with highly porous metals, particularly in younger patients

Bearing surfaces in Total Hip Arthroplasty (THA) may affect implant longevity and hence patient outcomes. This randomised clinical trial (RCT) determined how ceramic-on-ceramic bearing (CERAMIC) THA affected joint-specific pain, function and stiffness, and prosthesis fixation/longevity over 10 postoperative years compared with ceramic-on-highly-crosslinked-polyethylene bearing (POLYETHYLENE) THA. This is a follow-up to previously reported five year outcomes. Subjects aged less than 61 years were randomised to CERAMIC [n=48] or POLYETHYLENE [n=44] THA. Subjects were assessed using the Western Ontario McMaster Osteoarthritis Index (WOMAC) and the RAND 12-Item Health Survey (RAND-12) preoperatively, and at one, five and 10 years postoperatively. Plain radiographs were evaluated at 10 years for fixation and medical records were reviewed for revisions. Of 92 subjects, six (7%) died within 10 years; 68 (79%) survivors provided radiographic and/or clinical follow-up at 10 years postoperatively. Improvements seen at five years in both the WOMAC and RAND-12 were retained at 10 years with no group differences (p>0.48). There were no failures/loss of fixation related to bearing surfaces/wear in either group. Over 10 years, three subjects in the POLYETHYLENE group had revisions that were related to recurrent dislocation; two revisions were performed within two years of surgery and one further subject underwent revision at 7 years postoperatively. This is one of the first RCTs to examine 10 year outcomes between ceramic-on-ceramic and ceramic-on-highly-crosslinked-polyethylene bearing THA. Both bearing surfaces performed well out to 10 years in subjects who were less than 61 years at time of surgery

Tranexamic acid (TXA) is an effective medication to limit blood loss and transfusion requirements in association with contemporary total joint arthroplasty. TXA is in a class of medications termed anti-fibrinolytics due to their action to limit the breakdown of a clot that has already been formed. It is useful to note that TXA does not promote the formation of a clot, it simply limits the breakdown of already established clots. A recent systematic review and meta-analysis of randomised clinical trials of TXA use in total hip replacement demonstrated: 1) a substantial reduction in the proportion of patients who required transfusion and 2) no increase in DVT or PE. Similarly a recent Cochrane Database systematic review assessed Anti-fibrinolytic Use for Minimizing Perioperative Blood Transfusion and found tranexamic acid to be effective in reducing blood loss during and after surgery and to be free of serious adverse effects. In orthopaedic surgery, varying doses have been used over time. A pragmatic dosing approach for Total Knee and Total Hip patients has been used at the Mayo Clinic over the past 16 years: 1 gram IV over 10 minutes prior to incision (delivered at same time as pre-operative antibiotics) followed by 1 gram IV over 10 minutes at the time wound closure is initiated. Infusion rates greater than 100 mg/minute have been associated with hypotension and thus the recommendation for 1 gram over 10 minutes. A recent review of 1500 TKA patients at Mayo Clinic revealed a very low prevalence of clinically symptomatic DVT and PE when tranexamic acid was used with 3 different thromboembolic prophylaxis regimens (aspirin and foot pumps; coumadin; low molecular weight heparin). The safety of TXA for patients with coronary stents has not been fully clarified

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (CoCr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10-year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated CoCr stem. One study utilizing pain drawings did establish that if a CoCr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem cross-section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications

For 3 decades surgeons have vigorously debated whether it is reasonable to offer simultaneous bilateral total knee replacement (TKA) to patients. Even after this substantial period of time there remain no randomised clinical trials that have addressed this issue and thus, it remains difficult to fully evaluate both the relative risks and the absolute risks of bilateral simultaneous versus staged bilateral knee replacement. What has emerged over the past couple of decades, however, is an understanding that there is a subset of patients with substantial comorbidities such as pre-existent cardiac disease and advanced age for whom bilateral simultaneous knee replacement seems unwise. For younger or otherwise healthy patients the debate continues in 2016 and seems to be focused less on the data itself than on how individual surgeons come to reconcile the differences between Relative Risk and Absolute Risk. When data is pooled from multiple retrospective studies of simultaneous versus staged bilateral TKA there are 2 clear trends that appear in the data. First, the relative risk of certain substantial complications (cardiac, thromboembolic, neurologic, gastrointestinal, and death) seems to be higher after simultaneous bilateral TKA than after staged bilateral TKA. Oakes and Hanssen highlighted these differences in Relative Risk noting that for each of those 5 outcomes there was a 2 to 5 times greater incidence of these complications after bilateral versus unilateral TKA. At the same time, however, it is clear that for most medically uncomplicated patients the Absolute Risk of a major complication is still fairly low — it is likely that >93% of such patients can undergo simultaneous bilateral TKA without encountering a major complication. Individual surgeons and individual patients often view those kinds of statistics in markedly disparate ways. One set of surgeons and patients will view the Relative Risk as most important and be decidedly concerned about the 2–5 times higher risk of certain complications. Another set of patients and surgeons will look at the Absolute Risk as most important and determine that it is decidedly most likely (>93%) that an individual healthy patient will make it through bilateral simultaneous TKA without major medical complications. Overall the conclusions of Oakes and Hanssen from a decade ago remain relevant in 2016: the overall risk of a peri-operative complication is higher with simultaneous bilateral TKA … and this is particularly true for the risk of peri-operative death. While some surgeons and some patients will decide that the increases in Relative Risk is offset by the fairly low Absolute Risk of complications and thus, feel comfortable with bilateral simultaneous TKA, other patients and other surgeons will not

Any arthroplasty that offers superior function needs to be assessed using metrics that are capable of detecting those functions. The Oxford Hip Score (OHS), the Harris Hip Score (HHS) and WOMAC are patient reported outcome measures (PROMs) with well documented ceiling effects: following hip arthroplasty, many patients are clustered close to full marks following surgery. Two recent well conducted randomised clinical trials made exactly this error, by using OHS and WOMAC to detect a differences in outcome between hip resurfacing and hip arthroplasty despite published data already showing in single arm studies that these two procedures score close to full marks using either of these PROMS. We have already reported that patients with hip resurfacing arthroplasty (HRA) were able to walk faster and with more normal stride length than patients with well performing hip replacements. In an attempt to relate this functional superiority to an outcome measure that does not rely upon the use of expensive machinery, we developed a patient centred outcome measure (PCOM) based upon a method developed by Philip Noble's group, and the University of Arizona's Metabolic Equivalent of Task Index (MET). This PCOM allows patients to select the functions that matter to them personally against which the success of their own operation will be measured, with greater sensitivity to intensity than is achieved by the UCLA. Our null hypothesis was that this PCOM would be no more successful than the PROMs in routine use in discriminating between types of hip arthroplasty, and that there would be no difference in gait between patients following these procedures. From our database of over 800 patients whose gait has been assessed in the lab, we identified 22 patients with a well performing conventional THAs, and matched them for age, sex, BMI, height, preop diagnosis with 22 patients with a well performing conventional THA. Both were compared with healthy controls using the novel PCOM and in a gait lab. Results. PROMs for the two groups were almost identical, while HRA scored higher in the PCOM. The 9% difference was significant (p<0.05). At top walking speed, HRA were 10% faster, with a 9% longer stride length, both of these metrics also reached significance. Discussion. Function following hip replacement is very good, with high satisfaction rates, but the use of a PCOM, and objective measures of function reveal substantial inferiority of THA over THR in two well matched groups. This 9% difference is well over the 5% difference that is considered ‘clinically relevant’. When coupled with the very strong data regarding life expectancy and infection, this functional data makes a compelling case for the use of resurfacing in active adults

Over the past 30 years, cemented, cementless, and hybrid fixation options have been utilised with various total knee arthroplasty (TKA) implant systems. While cemented components are widely used and considered the most reliable method of fixation, historical results may not be applicable to contemporary patients, who are increasingly younger than 65 years of age. Moreover, the literature is not definitive on which method of TKA fixation obtains the best clinical, functional, and radiographic results. A recent Cochrane meta-analysis on roentgen stereophotogrammetric analysis (RSA) included five randomised clinical trials (RCTs) in 297 participants. The authors observed that cemented fixation of tibial components demonstrated smaller displacement in relation to cementless fixation. However, the risk of future aseptic loosening with uncemented fixation was approximately half that of cemented fixation (risk ratio = 0.47, 95% CI 0.24 to 0.92) with a 16% absolute risk difference between groups. Almost all included studies recorded functional measures of Knee Society and Hospital for Special Surgery knee scores, but the authors of each study found no significant difference between the groups. Recently, highly porous metals have become an attractive fixation option in TKA due to their biomechanical properties. In a large RCT of 397 patients, Pulido et al. found that uncemented highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with traditional cemented modular tibias. While longer-term studies are needed, cementless TKAs may be a durable and reliable alternative with highly porous metals, particularly in younger patients

The Oxford Hip Score (OHS), the Harris Hip Score (HHS) and WOMAC are examples of patient reported outcome measures (PROMs) have well documented ceiling effects, with many patients clustered close to full marks following arthroplasty. Any arthroplasty that offers superior function would therefore fail to be detectable using these metrics. Two recent well conducted randomised clinical trials made exactly this error, by using OHS and WOMAC to detect a differences in outcome between hip resurfacing and hip arthroplasty despite published data already showing in single arm studies that these two procedures score close to full marks using both PROMS. We had observed that patients with hip resurfacing arthroplasty (HRA) were able to walk faster and with more normal stride length than patients with well performing hip replacements, but that these objective differences in gait were not captured by PROMs. In an attempt to capture these differences, we developed a patient centred outcome measure (PCOM) using a method developed by Philip Noble's group. This allows patients to select the functions that matter to them personally against which the success of their own operation will be measured. Our null hypothesis was that this PCOM would be no more successful than the OHS in discriminating between types of hip arthroplasty. 22 patients with a well performing Hip Resurfacing Arthroplasty were identified. These were closely matched by age, sex, BMI, height, preop diagnosis with 22 patients with a well performing conventional THA. Both were compared with healthy controls using the novel PCOM and in a gait lab. Results. PROMs for the two groups were similar, while HRA scored higher in the PCOM. The 9% difference was significant (p<0.05). At top walking speed, HRA were 10% faster, with a 9% longer stride length. Discussion. Outcome measures should be able to detect differences that are clinically relevant to patients and their surgeons. The currently used hip scores are not capable of delivering this distinction, and assume that most hip replacements are effectively perfect. While the function of hip replacements is indeed very good, with satisfaction rates high, objective measures of function are essential for innovators who are trying to deliver improved functional outcome. The 9% difference in PCOM found in this small study reflects the higher activity levels reported by many, and of similar magnitude to the 10% difference in top walking speed, despite no detectable difference in conventional PROMS. PCOMs may offer further insight into differences in function. For investigators who wish to develop improvements to hip arthroplasty, PCOMs and objective measures of gait may describe differences that matter more to patients than conventional hip scores

Only a little over a decade ago the vast majority of primary total hip replacements performed in North America, and indeed globally, employed a conventional polyethylene insert, either in a modular version or in a cemented application. Beginning in the early 2000's there was an explosion in technology and options available for the bearing choice in total hip arthroplasty. Highly crosslinked polyethylene was introduced in 1998, and within a few short years the vast majority of polyethylene inserts performed in North America were manufactured from this material. Globally there was a mixed picture with variable market penetration. Surgeons had seen historically poor results with attempts at “improving” polyethylene in the past and many were hesitant to use this new technology. Many randomised clinical trials have been performed and all have shown to a greater or lesser degree, that indeed the highly crosslinked polyethylene insert has undergone less linear and volumetric wear than its more conventional counterpart. This replicates well the hip simulator data. The challenge, however, is as we approached mid-term results, orthopaedic manufacturers began altering the polyethylene to improve wear and improve mechanical strength. Therefore while 10-year and greater data will ultimately be published, the actual polyethylene in use at that time will be a different material. Additionally, while wear rates are undoubtedly lower, we are still waiting for long-term results of actual osteolytic lesion development and the effect that highly cross-linked polyethylene will have on this clinical scenario. That being said, with over a decade of clinical experience, unquestionably highly crosslinked polyethylene has truly been a revolution in design, essentially eliminating polyethylene wear as an early failure mode. The question still remains as to the best material for the femoral ball. Essentially two options exist – cobalt chrome and ceramic (Delta). There are theoretically advantages to ceramic heads; however they come at a cost premium: 1.) To date there have been no published reports that demonstrate any improved clinical outcomes with the use of ceramic heads. In fact, the Australian registry demonstrates that the cumulative revision rate is lowest with CoCr heads (at 10 years, 4.3% with CoCr on XLPE and 4.6% with ceramic on XLPE). 2.) Costs continue to be significantly higher for ceramic heads. A price premium of 2–4× higher cost for ceramic over CoCr heads exists in most global markets. 3.) Trunion issues. An emerging concern is corrosion at the head neck junction in THA. Ceramic heads should theoretically have a lower incidence of taper corrosion. To date this is unproven, as is the actual incidence of this as a significant clinical problem

Only a little over a decade ago the vast majority of primary total hip replacements performed in North America, and indeed globally, employed a conventional polyethylene insert, either in a modular version or in a cemented application. Beginning in the early 2000's there was an explosion in technology and options available for the bearing choice in total hip arthroplasty. Highly cross-linked polyethylene was introduced in 1998, and within a few short years the vast majority of polyethylene inserts performed in North America were manufactured from this material. Globally there was a mixed picture with variable market penetration. Surgeons had seen historically poor results with attempts at “improving” polyethylene in the past and many were hesitant to use this new technology. Many randomised clinical trials have been performed and all have shown to a greater or lesser degree, that indeed the highly cross-linked polyethylene insert has undergone less linear and volumetric wear than its more conventional counterpart. This replicates well the hip simulator data. The challenge, however, is as we approached mid-term results, orthopaedic manufacturers began altering the polyethylene to improve wear and improve mechanical strength. Therefore while ten-year and greater data will ultimately be published, the actual polyethylene in use at that time will be a different material. Additionally while wear rates are undoubtedly lower, we are still waiting for long-term results of actual osteolytic lesion development and the effect that highly cross-linked polyethylene will have on this clinical scenario. That being said, with over a decade of clinical experience, unquestionably highly cross-linked polyethylene has truly been a revolution in design, essentially eliminating polyethylene wear as an early failure mode. The question still remains as to the best material for the femoral ball. Essentially two options exist – cobalt chrome (CoCr) and ceramic. There are theoretically advantages to ceramic heads; however, they come at a cost premium:. To date there have been no published reports that demonstrate any improved clinical outcomes with the use of ceramic heads. In fact, the Australian registry demonstrates that the cumulative revision rate is lowest with CoCr heads (at 10 years, 4.3% with CoCr on XLPE and 4.6% with ceramic on XLPE). Costs continue to be significantly higher for ceramic heads. A price premium of 2–4x higher cost for ceramic over CoCr heads exists in most global markets. Trunnion issues. An emerging concern is corrosion at the head neck junction in THA. Ceramic heads should theoretically have a lower incidence of taper corrosion. To date this is unproven, as is the actual incidence of this as a significant clinical problem

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10-year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications