Implant selection in TKA remains highly variable. Surgeons consider pre-operative deformity, patient factors such as BMI and bone quality, surgical experience, retention or substitution for the PCL, type of articulation and polyethylene, cost, and fixation with or without cement. We have most frequently implanted the same implant for the majority of patients. This is based on the fact that multiple large series of TKAs have demonstrated that the most durable TKAs have been non-modular metal-backed tibial components, retention of the PCL, with a cemented all-polyethylene patellar component. Polymer wear must be addressed for long-term durability.

One method for reducing polyethylene wear is eliminating modularity between a metal-backed tray and the articular bearing surface. This can be done with a metal-backed implant as with the IB-1, AGC, Vanguard Mono-lock, or with elimination of the metal backing via a one piece all-polyethylene tibial component. The all-polyethylene implants appear design and patient sensitive. We observed higher clinical failure rates in a flat-on-flat design. Other authors have observed improved survivorship with coronal dishing of the articular surfaces which centralises osseous stresses. All-polyethylene implants have promise in the future but require proven design and fixation design features

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal peri-operative management reducing pain, nausea, and length of stay leading to outpatient joint replacement surgery with recovery at home. The surgical procedures included in the outpatient program have expanded from Partial Knee Arthroplasty to Primary TKA, Primary THA, and selected revision cases. Emerging data demonstrate safety, reduced cost, and reduced resources.

Since 2011, we helped develop and implement an outpatient program as part of 76 participating physician-owned ambulatory facilities in 19 states − 19,415 joint replacements have been performed. The cohort included 6,146 TKA, 5,102 THA, 7,227 partial knee replacements, and 940 revisions and TSA. Patients had a mean age of 58 years and 50% of the patients were female; 97% of patients were discharged same day, the deep infection rate was 0.2%, and the readmission rate was 0.3%.

The outpatient program centers on the patient needs, family engagement, essentials of home recovery, pre-operative education, efficient surgery, and a surgeon controlled environment with highly standardised care. This is a distinct shift in today's health care environment, which has seen the expansion of regulatory demands; focus on Electronic Health Records (EHR), and distractions from real discussions of demonstrated value creation. The future is bright for both ASC and hospital development of successful outpatient joint replacement program for patients and surgeons alike.

Not all degenerative knees need a total knee replacement. Over the last few decades we have shifted our surgical treatment of end-stage osteoarthritis (OA) of the knee to a “compartmental approach” resulting in approximately half of end-stage OA knees receiving a partial knee replacement. Of these an emerging procedure is isolated lateral compartment replacement with the indications being isolated bone-on-bone osteoarthritis or avascular necrosis of the lateral compartment of the knee. Associated significant patellofemoral disease and inflammatory arthritis are contraindications. The purpose of this study is to present the indications, surgical technique, and early outcome of lateral partial knees from our institution.

From Aug 2011 until June 2017 we have performed 3,548 knee arthroplasties. Of these 147 were fixed bearing lateral partial knee replacements via a lateral parapatellar approach (4%), 1,481 medial partial knee replacements (42%), and 1,920 total knee replacements (54%). The average age was 66 years old and 76% were female. Average follow-up in the lateral partials was 1.3 years (range 0.5 years to 6 years). Knee Society Scores improved from 41 (pre-op) to 86 points (post-op). Range of motion improved from 6 – 113 degrees (pre-op) to 0 – 123 degrees (post-op). No knees were revised to a TKA. One knee required I&D for traumatic wound dehiscence.

This is the largest single center series of lateral partial knee replacements. We have observed this cohort to have more female patients and gain additional range of motion compared to our historic cohorts of TKA's. Longer-term follow-up is needed for determination of implant and unreplaced compartment survivorship. We believe the lateral partial knee replacement to be a viable option for isolated lateral compartment disease in approximately 4% of patients.

Refinement of surgical techniques, anesthesia protocols, and patient selection has facilitated this transformation to same day discharge for arthroplasty care, most notably Partial Knee Arthroplasty (PKA). The trend for early discharge has already happened for procedures formerly regarded as “inpatient” procedures such as upper extremity surgery, arthroscopy, ACL reconstruction, foot and ankle procedures, and rotator cuff repair. Our program began focused on PKA and has now expanded to primary TKA and THA, and select revision cases. Over the past few years we have performed 1,230 knee arthroplasty procedures with no readmissions for pain control. Average age and age range is identical to our inpatient cohort for our partial knee cases. Patient selection is based on medical screening criteria and insurance access. PKA is the ideal procedure to begin your transition to the outpatient space. We currently perform medial PKA, lateral PKA, and patellofemoral arthroplasty as an outpatient.

The program centers on the patient, their family, home recovery, preoperative education, efficient surgery, and represents a shift in the paradigm of arthroplasty care. It can be highly beneficial to patients, surgeons, anesthesia, facility costs, and payors as arthroplasty procedures shift to the outpatient space.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. This has reduced length of stay in the inpatient hospital environment opening the opportunity for cost savings and even outpatient joint replacement surgery for appropriately selected patients. The hallmark of this program is meticulous protocol execution. Preemptive pain control with oral anti-inflammatory agents, gabapentin, regional anesthetic blocks that preserve quad function for TKA (adductor canal block) and pericapsular long acting local anesthetics with the addition of injectable ketorolac and IV acetaminophen are key adjuncts. Over the past two years utilizing this type of program over 60% of our partial knee replacement patients are now returning home the day of surgery.

Concerns over readmission are appropriate. The rates of complications and readmissions are less than our inpatient cohort in appropriately selected cases with a standardised care map. We believe this brings the best VALUE to the patients, surgeons, and the arthroplasty system.

Implant selection in TKA remains highly variable. Surgeons consider preoperative deformity, surgical experience, retention or substitution for the PCL, type of articulation and polyethylene, and fixation with or without cement. We have most frequently implanted the same implant for the majority of patients. This is based on the fact that multiple large series of TKA's have demonstrated that the most durable TKA's have been non-modular metal backed tibial components, retention of the PCL, with a cemented all poly patellar component.

The debate of how to handle the PCL continues. In most studies at 10 years there is little reported difference. Second decade concerns usually result from polyethylene issues related to polymer wear. Sagittal “dishing” or ultracongruent implants may be a middle road that allow PCL release or resection and controlled kinematics offering improved short term results. Long term function remains the goal and it appears a CR knee offers that capacity.

Newer implants such as “high flex” and “gender” specific designs have not demonstrated significant functional improvements in controlled series. Uncemented knees in many series have performed well for many surgeons from a fixation standpoint. Polymer wear must be addressed for long term durability.

Subcapital fractures about the hip continue to be a common clinical scenario with which we all face. There are estimated to be over 350,000 hip fractures annually in the U.S. with 40% being displaced femoral neck fractures. The mean cost is over $30,000. Optimizing surgical care is essential with the overall goal being to perform the most effective treatment with the lowest risk of reoperation that provides the best postoperative function and pain relief.

In the “young” (which is often defined as whatever age is younger than you!) reduction and internal fixation is often the most effective retaining the native femoral head. The risk of non-union and AVN is often less than potential complications that can follow an arthroplasty with 40% of displaced fractures treated with ORIF eventually requiring reoperation. Essentially for every 100 patients that undergo ORIF for displaced femoral neck fracture, choosing arthroplasty instead results in 17 conversions avoided.

In the “elderly” in general we treat all displaced fractures with a total hip replacement which reduced re-admissions and is more cost effective for displaced femoral neck fractures. Aside from the medical morbidity following an arthroplasty dislocation is the primary concern. We have found the anterolateral approach reduces this significantly. Non-displaced fractures that are valgus impacted and biomechanically stable are treated with cannulated screws. Perhaps it can be argued that a hemiarthroplasty (bipolar or monopolar) has a lower risk of dislocation compared to a total hip replacement if performed by a surgical team with less frequent total hip replacement experience. However, total hip replacement results in less pain and better function when the patients are independent with intact mental status (patient not the surgeon…!).

My algorithm is non-displaced valgus impacted or “stable” fractures undergo cannulated screws and the displaced fractures receive a total hip arthroplasty via an anterolateral approach.

Acetabular defects often result from osteolysis with or without component loosening. The goals of acetabular reconstruction in the face of significant rim or column deficiencies are to create a stable acetabular construct, which will facilitate acetabular component biologic fixation and long-term stability. Four reconstructive techniques have emerged to treat these defects: 1) Large allografts, 2) Cup / Cage constructs, 3) Metallic augments and uncemented hemispherical cups, and 4) Triflange custom implants.

While all of these techniques have demonstrated success, we have elected to pursue triflange implants to improve fixation on host bone, allow modular liner options, facilitate enhanced fixation surfaces, match patient complex geometries, opportunity to utilise locking screws, and possibly reduce surgical operative time. Furthermore, screw paths and lengths can be planned pre-operatively along with custom pelvic model generation which makes surgical exposure and reconstructive more understandable.

Multiple studies have shown excellent survivorship in series of the most challenging acetabular reconstructions.

Refinement of surgical techniques, anaesthesia protocols, and patient selection have facilitated this transformation to same day discharge for arthroplasty care, most notably Partial Knee Arthroplasty (PKR). The trend for early discharge has already happened for procedures formerly regarded as “inpatient” procedures such as upper extremity surgery, arthroscopy, ACL reconstruction, foot and ankle procedures, and rotator cuff repair. Our program began focused on Partial Knee Arthroplasty (PKA) and has now expanded to primary TKA and THA, and select revision cases. Over the past few years we have performed 1,230 Knee Arthroplasty procedures with no readmissions for pain control. Average age and age range is identical to our inpatient cohort for our partial knee cases. Patient selection is based on medical screening criteria and insurance access. PKA is the ideal procedure to begin your transition to the outpatient space. We currently perform medial PKA, lateral PKA, and patellofemoral arthroplasty as outpatient cases.

The program centers on the patient, their family, home recovery, pre-operative education, efficient surgery, and represents a shift in the paradigm of arthroplasty care. It can be highly beneficial to patients, surgeons, anaesthesia, facility costs, and payors as arthroplasty procedures shift to the outpatient space.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. This has reduced length of stay in the inpatient hospital environment opening the opportunity for cost savings and even outpatient joint replacement surgery for appropriately selected patients. The hallmark of this program is meticulous protocol execution. Pre-emptive pain control with oral anti-inflammatory agents, gabapentin, regional anesthetic blocks that preserve quad function for TKA (adductor canal block) and pericapsular long acting local anesthetics with the addition of injectable ketorolac and IV acetaminophen are key adjuncts. Over the past two years utilizing this type of program over 60% of our partial knee replacement patients are now returning home the day of surgery.

Concerns over readmission are appropriate. The rates of complications and readmissions are less than our inpatient cohort in appropriately selected cases with a standardised care map. We believe this brings the best VALUE to the patients, surgeons, and the arthroplasty system.

Yes the paradigm is changing!!!

Refinement of surgical techniques, anesthesia protocols, and patient selection has facilitated this transformation to same day discharge for arthroplasty care. The trend for early discharge has already happened for procedures formerly regarded as “inpatient” procedures such as upper extremity surgery, arthroscopy, ACL reconstruction, foot and ankle procedures, and rotator cuff repair. Our program began focused on Partial Knee Arthroplasty (PKA) and has now expanded to primary TKA and THA, and select revision cases. Over the past few years we have performed: 138 TKA, 111 THA, 244 Partial KA, 6 RevTKA, and 6 RevTHA with no readmissions for pain control. With preoperative Hgb above 11 combined with Tranexamic Acid we have had no transfusions. Medical optimization is critical to the safety and success of patient selection for same day discharge. We utilise a standardised format for preadmission testing.

The program centers on the patient, their family, home recovery, preoperative education, efficient surgery, and represents a shift in the paradigm of arthroplasty care. It can be highly beneficial to patients, surgeons, anesthesia, facility costs, and payors as arthroplasty procedures shift to the outpatient space.

Perioperative fracture during routine THA represents one of the “not so fresh” feelings that occur for both patients and surgeons. With the increase in the use of uncemented implants and MIS techniques this truly is a problem on the rise. We have examined and quantified the risk factors associated with proximal femoral fracture during THA. Risk factors (risk ratios) identified were: uncemented stems (8.9), anterolateral approach (7.4) and female gender (2.2). Fortunately, treatment with cerclage wiring for uncemented stems has facilitated excellent stem stability and acceptable survivorship with many different femoral component designs. Reduced proximal geometry stems that better match the endosteal osseous anatomy have reduced fracture rates at our institution and maintained excellent stem survivorship. New data examining this design will be presented.

In our series, cemented stems, however, had decreased survivorship in the presence of a proximal femoral fracture. MIS techniques may accelerate rehabilitation but they certainly permit limited visibility of the proximal femoral and acetabular anatomy and may result in less accurate component position. Relatively high fracture rates in series of MIS-THA have been reported. A bigger concern, however, is the unrecognised fracture that displaces postoperatively and requires a return to surgery for treatment with or without revision and mandates that we “see it before it sees us!” Cerclage wiring with looped Luque wires has been our treatment of choice for many years. Wires are significantly less expensive than cables and have proven to be durable in our series. This technique allows intraoperative repositioning and variable tightening in multiple locations. Cable fretting and breakage have been common in our experience with braided cable devices. Acetabular fracture during uncemented THA is most likely an under-reported occurrence and has been associated with elliptical component designs and under-reaming. In the presence of a stable cup, long-term performance has been acceptable.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. The hallmark of this program is preemptive pain control with oral anti-inflammatory agents, gabapentin, IV acetaminophen, regional anesthetic blocks that preserve quadriceps function for TKA (adductor canal block) and pericapsular local anesthetics. Over the past two years utilising this type of program over 50% of our joint replacement patients are now returning home the day of surgery.

Metal-backed tibial components in total knee arthroplasty (TKA) currently dominate the orthopaedic market due to intra-operative flexibility afforded by modularity. Metal-backing was first used in TKA as a method to potentially improve loading distributions over the tibial plateau at the interface between the prosthesis and the supporting cancellous bone. Many studies have compared metal-backed and all-polyethylene tibial components with variable survivorship. We have found decreased clinical survivorship with all-polyethylene Anatomic Graduated Component (AGC) TKA's (Biomet, Inc, Warsaw, Indiana) compared to the non-modular metal-backed design at 10-year follow up, 68% vs 98%, respectively. Loosening or bony collapse beneath the medial plateau accounted for 74% of failures in our AGC all-polyethylene cohort. We hypothesised that all-polyethylene tibial components may lead to increased strains in the proximal tibia with the AGC-TKA design, possibly correlating to osseous overload in the medial compartment and accounting for the increased observed rates of clinical failures in the all-polyethylene group. Finite element studies and our lab studies have shown that metal-backing reduces system stresses in the PMMA bone cement, as well as in the underlying cancellous bone. Overall, in every measurement region with a statistically significant difference in shear strain, higher strain was measured in the all-polyethylene implanted tibiae compared to metal-backed components. Statistically significant increases in strain from 126 μɛ (p=0.0131) to 745 μɛ (p=0.0011) and from 40% (p=0.0010) to 587% (p=0.0054) were seen in the all-polyethylene experimental group. We believe this may correlate with the higher failure rates we have observed in the AGC all-polyethylene cohort compared to the metal-backed cohort from our institution. Other all-poly TKA designs with varied articular congruities may afford improved or equal survivorship to metal backed implants at a reduced cost.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. This has reduced length of stay in the inpatient hospital environment opening the opportunity for cost savings and even outpatient joint replacement surgery for appropriately selected patients. The hallmark of this program is pre-emptive pain control with oral anti-inflammatory agents, gabapentin, regional anesthetic blocks that preserve quad function for TKA (adductor canal block) and pericapsular long acting time release local anesthetics with the addition of injectable ketorolac and IV acetaminophen. Over the past two years utilising this type of program over 60% of our partial knee replacement patients are now returning home the day of surgery.

We currently utilise a long acting local anesthetic delivery medication consisting of microscopic, spherical, lipid-based particles composed of a honeycomb-like structure of numerous nonconcentric internal aqueous chambers containing encapsulated bupivacaine separated from adjacent chambers by lipid membranes. Bupivacaine is released from the particles with diffusion of the drug over an extended period of time that more closely matches the time course of postsurgical pain following joint replacement surgery. Trials have demonstrated that a single dose administered via deep tissue infiltration is effective at reducing pain up to 72 hours. This has been trialed in TKA as well.

Perhaps the most significant developments in joint replacement surgery in the past decade have been in the area of multimodal pain management. This has reduced length of stay and opened the opportunity for cost savings and even outpatient joint replacement surgery for appropriately selected patients. The hallmark of this program is preemptive pain control with oral anti-inflammatory agents, gabapentin, regional anesthetic blocks that preserve quad function for TKA (adductor canal block) and long acting local anesthetics with the addition of injectable ketorolac and acetaminophen. Over the past two years utilising this type of program over 60% of our partial knee replacement patients are now returning home the day of surgery.

We currently utilise a long acting local anesthetic delivery medication consisting of microscopic, spherical, lipid-based particles composed of a honeycomb-like structure of numerous nonconcentric internal aqueous chambers containing encapsulated bupivacaine separated from adjacent chambers by lipid membranes. Bupivacaine is released from the particles with diffusion of the drug over an extended period of time that more closely matches the time course of postsurgical pain following joint replacement surgery. Trials have demonstrated that a single dose administered via deep tissue infiltration is effective at reducing pain up to 72 hours.

Partial knee arthroplasty is making a resurgence as many patients and surgeons are realising that there are good options for preserving normally functioning knee tissues when facing end-stage knee OA without having to automatically proceed to TKA. What are potential advantages of this type of reasoning and could “less be more”? Limited comparative data exists comparing the functional results of partial and total knee replacement surgery. This study will report on patient satisfaction and residual symptoms following TKR, fixed bearing PKR, and mobile bearing PKR. What do the patients say when we aren't around?

TKA is not a benign treatment for isolated unicompartmental knee disease. A multicenter study examining 2,919 TKA's and UKA's found lower rates of overall complications at 11% for TKA's and 4.3% for UKA's. Significant variables for TKA included longer length of stay, more patients sent to an ECF, higher manipulation rate, higher readmission, ICU admission, and transfusion rates. Bolognesi, et al examining 68,790 TKA and UKA, reproduced these results with lower DVT/PE, deep infection rates and lower death rates. The 1 year and 5 year revision rates were higher for UKA's and have been hypothesised to be lower thresholds for revision of dissatisfied UKA vs a TKA with well-fixed implants.

Functional improvements may be better for UKA vs TKA further substantiating the evidence that “less is more” for the surgical treatment of isolated compartmental disease of the knee.

We conducted a multicenter independent survey of 1,263 patients (age 18–75) undergoing primary TKR and PKR for non-inflammatory knee DJD. We examined 13 specific questions regarding pain, satisfaction, and residual symptoms after knee arthroplasty. An independent third party (University of Wisconsin Survey Center) collected data with expertise in collecting healthcare data for state and federal agencies. Multivariate analysis was conducted, significance was set at p<0.05 and adequate power >0.8 was achieved. We controlled for gender, age, income, minority status, and surgical location in the multivariate analysis.

Univariate analysis revealed PKR patients were more likely to be younger, male, and have an income greater than $25,000 than TKR patients. Multivariate analysis showed that mobile bearing PKR patients were 1.81 times more likely to report that their operative knee felt “normal” (p = 0.0109) and 2.69 more likely to report satisfaction with ability to perform activities of daily living than TKR recipients (p = 0.0058). Mobile bearing PKR patients were 44% less likely to report grinding/popping/clicking in the knee (p = 0.0142), 39% less likely to report knee swelling (p = 0.0351), and 40% less likely to report knee stiffness in the last 30 days (p = 0.0167) compared to TKR's. Fixed bearing PKR patients were 51% less likely to experience problems getting in and out of a car compared to TKR patients (p = 0.0129). Fixed bearing PKR's were 60% less likely to be satisfied with the degree of pain relief than TKR (p = 0.0113). The remaining questions revealed a trend for advantages in all categories for the MB-PKR compared to TKR but did not reach statistical significance.

This study demonstrated that patient satisfaction is higher for MB-PKR than TKR with patients more likely reporting the knee to feel normal and that they were more able to perform activities of daily living. Fixed bearing devices were slightly more likely to report less pain relief than TKR. Mobile bearing partial knee replacement had fewer residual symptoms than fixed bearing PKR.

Component and limb alignment are important considerations during Total Knee Arthroplasty (TKA). Three-dimensional positioning of TKA implants has an effect on implant loosening, polyethylene stresses, and gait. Furthermore, alignment, in conjunction with other implant and patient variables such as body mass index (BMI) influence osseous loading and failure rates. Fortunately, implant survivorship after TKA has been reported to be greater than 95% at 20 years, despite up to 28% of TKAs having component position greater than 3 degrees from neutral. How good are we at positioning TKA implants with standard instrumentation? Ritter, et al examined 6,070 primary TKAs and found that from 2 degrees – 7 degrees of valgus, the failure rate was 0.5% for limb alignment. Importantly 28% of the TKAs were outside the 2 degrees – 7 degrees range in the hands of experienced surgeons. What about cases with retained hardware or deformities that preclude IM or EM guides.

Clearly there is room for improvement in surgical technique, but this improvement must be (1) time efficient and cost effective; (2) have a low complication rate, and (3) be reproducible with a minimal learning curve. One of the technologies that has been developed to help surgeons implant and position TKA components is a patient matched guide. Preoperative computerised planning of the arthroplasty, development of patient specific guides, combined with limited mechanical instruments has been a significant step forward for the surgeon and patient.

“The logistical benefits include possible decreased operating room time, decreased turnover time, less time spent sterilising and preparing trays, less inventory, less strain on surgical technicians and nurses, and no capital cost associated with computer navigation. Patient benefits include potentially less tourniquet time, less surgical exposure, no requirement of intramedullary canal preparation, and improved mechanical alignment, which may translate to increased implant longevity. Surgeon benefits include potentially more accurate landmark registration than computer navigation, more efficient surgery, decreased intraoperative stress due to less required decision making, and the ability to perform more surgeries due to time saved.”

Ng, et al compared 569 TKAs performed with patient-specific positioning guides and 155 with manual instruments. The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6 degrees) was similar to manual instrumentation (181.1 degrees), but there were fewer ± 3 degrees hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%).

Peri-operative fracture during routine THA represents one of the “not so fresh” feelings that occur for both patients and surgeons. With the increase in uncemented implants and MIS techniques this truly is a problem on the rise. We have recently examined and quantified the risk factors associated with proximal femoral fracture during THA. Risk factors (risk ratios) identified were: uncemented stems (8.9), anterolateral approach (7.4) and female gender (2.2). Fortunately, treatment with cerclage wiring for uncemented stems has facilitated excellent stem stability and acceptable survivorship with many different femoral component designs. Reduced proximal geometry stems that match the endosteal osseous anatomy have reduced fracture rates at our institution. In our series, cemented stems, however, had decreased survivorship in the presence of a proximal femoral fracture. MIS techniques may accelerate rehabilitation but they certainly permit limited visibility of the proximal femoral and acetabular anatomy and may result in less accurate component position. Relatively high fracture rates in series of MIS-THA have been reported. A bigger concern, however, is the unrecognised fracture that displaces postoperatively and requires a return to surgery for treatment with or without revision and mandates that we “see it before it sees us!” Cerclage wiring with looped Luque wires has been our treatment of choice for many years. Wires are significantly less expensive than cables and have proven to be durable in our series. They allow intraoperative repositioning and variable tightening in multiple locations. Cable fretting and breakage has been common in our experience with braided cable devices. Acetabular fracture during uncemented THA is most likely an under-reported occurrence and has been associated with elliptical component designs and under-reaming. In the presence of a stable cup, long-term performance has been acceptable.

Total Hip Replacement has become the most successful operation in the latter half of the 20th century for relief of pain and restoring function of the arthritic hip. Many improvements in surgical technique and implant technology have enhanced recovery, reduced complications, and increased implant survivorship. Minimising the complications of impingement, dislocation, bearing-wear, and implant loosening remain goals for surgeons and implant design.

Patients at higher risk for post-operative dislocation including patients with high pre-op hip ROM, femoral neck fracture, posterior surgical approaches, smaller femoral head sizes, and most importantly folks undergoing revision THA may influence dislocation as much as component position. A tripolar type of articulation, where there is an additional bearing with a mobile polyethylene component between the prosthetic head and the acetabular shell, increase functional head diameter, reduce neck – component impingement, and reduce dislocation. These implants may greatly assist in the treatment of recurrent dislocation of the hip and in reducing the high rate of dislocation that follows revision THR as proven by many French authors connecting the world to this innovative technology.

Aseptic loosening of monolithic cups (through inadequate initial fixation) and inner smaller femoral head dislocation from the larger polyethylene head remain risks with dual mobility deign that require longer-term follow-up of newer designs before we declare victory in this space. It appears in patients at high risk for dislocation that a dual mobility type articulation may be worth the potential trade off of increased volumetric wear, intra-prosthetic dislocations, and acetabular loosening. Without additional outcomes data in this space wide spread use should be cautious.

Component and limb alignment are important considerations during Total Knee Arthroplasty (TKA). Three-dimensional positioning of TKA implants has an effect on implant loosening, polyethylene stresses, and gait. Furthermore, alignment, in conjunction with other implant and patient variables such as body mass index (BMI) influence osseous loading and failure rates. Fortunately, implant survivorship after TKA has been reported to be greater than 95% at 20 years, despite up to 28% of TKAs having component position greater than 3 degrees from neutral. How good are we at positioning TKA implants? Ritter, et al examined 6,070 primary TKAs and found that from 2–7 degrees of valgus, the failure rate was 0.5% for limb alignment. Importantly 28% of the TKAs were outside the 2–7 degree range in the hands of experienced surgeons. Clearly there is room for improvement in surgical technique, but this improvement must be (1) time efficient and cost effective; (2) have a low complication rate, and (3) be reproducible with a minimal learning curve. A number of technologies have been developed to help surgeons implant and position TKA components including intramedullary guides, patient matched guides based on pre-operative imaging, Computer Assisted Surgery (CAS) based on line-of-sight navigation, and most recently, hand-held navigation. All of these techniques have distinct advantages and disadvantages, but we have found that hand-held navigation in TKA meets the prerequisites. Nam, et al reported the first series with a handheld device in 42 knees, and was able to position 95% of the tibial components within 2 degrees of targeted sagittal slope and 96% within 3 degrees of coronal alignment. Advantages of hand-held navigation include low cost, minimal learning curve, reproducibility surgeon to surgeon, and time efficiency (usually taking less than 3 minutes). The disposable device can be used on all patients with all deformities, including those with retained hardware. Hand held navigation devices create a virtual alignment framework from known osseous landmarks, and this framework is used to position tibial and femoral cutting guides on the bone. Using tibial osseous landmarks, including the ACL footprint proximally and the medial and lateral malleoli distally, the device allows real-time feedback of tibial slope and coronal alignment. On the femur, the device locates and references the centre of rotation of the hip and the centre of the distal femur, which allows for real-time calculation of distal femoral valgus and flexion for the distal femoral cutting block. Receiving three-dimensional, real-time feedback of coronal and sagittal alignment, as well as resection depth, combining limited mechanical instruments aided by hand-held navigation devices is a significant step forward. Thus, this technology represents a significant help to the surgeon and patient.

Partial knee arthroplasty is making a resurgence as many patients and surgeons are realising that there are good options for preserving normally functioning knee tissues when facing end-stage knee OA without having to automatically proceed to TKA. What are potential advantages of this type of reasoning and could “less be more”? TKA is not a benign treatment for isolated unicompartmental knee disease. A multicentre study examining 2,919 TKA's and UKA's found lower rates of overall complications at 11% for TKA's and 4.3% for UKA's. Significant variables for TKA included longer length of stay, more patients sent to an ECF, higher manipulation rate, higher readmission, ICU admission, and transfusion rates. Bolognesi, et al examining 68,790 TKA and UKA, reproduced these results with lower DVT/PE, deep infection rates and lower death rates. The 1 year and 5 year revision rates were higher for UKA's and have been hypothesised to be lower thresholds for revision of dissatisfied UKA vs. a TKA with well-fixed implants.

Hospital costs continue to rise for arthroplasty procedures. Outpatient procedures may decrease cost, improve patient satisfaction, and improve physician efficiency. Our outpatient UKA program includes pre-op medical assessment and education, regional and pre-emptive anesthesia, post-op home care prn, and coordination with family and therapy providers. We utilise risk stratification mobile foot pumps, IV heparin, and oral ECASA for DVT prophylaxis. Patient satisfaction is very high in the outpatient setting.

We have performed 60 inpatient UKAs and 82 outpatient UKAs this year. To date we have had no acute hospital admissions. This program has worked well in our hands but may not be generalisable to all centres and all patients.

Functional improvements may be better for UKA vs. TKA further substantiating the evidence that “less is more” for the surgical treatment of isolated compartmental disease of the knee.

Introduction

This study compares the incidence of post-operative complications (within 90 days) following primary total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA).