A majority of patients present with varus alignment and predominantly medial compartment disease. The secret of success in osteoarthritis (OA) treatment is patient selection and patient specific treatment. Different wear patterns have been described and that knowledge should be utilised in modern knee surgery. In case of isolated anteromedial OA, unicompartmental knee arthroplasty (UKA) should be one of the therapeutic options available to the knee surgeon. The discussion not to offer a UKA to patients is based on the fear of the surgeon not being able to identify the right patient and not being able to perform the surgery accurately. The common modes of failure for UKA, which are dislocation or overcorrection leading to disease progression, can be avoided with a fixed bearing implant. Wear can probably be avoided with newer polyethylenes and avoidance of overstuffing in flexion of the knee. Revision for unexplained pain and unknown causes should disappear once surgeons understand persistent pain after surgery much better than they do today. The choice in favor of UKA is a choice of function over survivorship, a choice for reduced comorbidity and lower mortality. Many of the common problems in TKA are not an issue in UKA. Component overhang, decreased posterior offset, changed joint line height, gap mismatch, flexion gap instability, lift off and paradoxical motion hardly exist in UKA if the replacement is performed according to resurfacing principles with respect for the native knee anatomy. New technologies like navigation, PSI and robotics will help with alignment and component positioning. Surgeon education and training should allow over time UKA to be performed by all of us

For medial compartment disease UKR has many advantages over TKR. They give better function, faster recovery, lower morbidity and mortality but have a higher revision rate. Matched studies from the England and Wales National Joint Registry showed they are 60% more likely to achieve excellent outcomes (OKS>41) and 30% more likely to have excellent satisfaction. UKR patients were discharged 1.4 days earlier, had 35% less readmissions and 50% less major complications such as DVT/PE, infection, CVA and MI. The death rate was significantly lower: The hazard ratios being 0.2x at 30 days, 0.5x at 90 days and 0.85x at 8 years. However at 8 years the revision rate was 2x higher and the reoperation rate was 1.4x. If 100 patients receiving TKR had UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years. If patients were aware of this most would select a UKR. The main reason why UKR have a high revision rate in registries is that most surgeons do small numbers and restrict their use to patients with very early disease, who often do badly. In the NJR 8% of knees are UKR and surgeons do on average 5 per year. Surgeons doing more than 20% of knees as UKR have a much lower re-operation rate which is similar to that of TKR. The Mobile bearing UKR can safely be used in up to 50% allowing many patients to have the advantages of UKR and a low re-operation rate

The role of unicompartmental knee arthroplasty (UKA) in spontaneous osteonecrosis of the knee (SONK) remains controversial, even though SONK usually involves only medial compartment of the knee joint. We aimed to compare the survival rate and clinical outcomes of UKA in SONK and medial compartment osteoarthritis (MOA) via a meta-analysis of previous studies. MEDLINE database in PubMed, the Embase database, and the Cochrane Library were searched up to January 2018 with keywords related to SONK and UKA. Studies were selected with predetermined inclusion criteria: (1) medial UKA as the primary procedure, (2) reporting implant survival or clinical outcomes of osteonecrosis and osteoarthritis, and (3) follow-up period greater than 1 year. Quality assessment was performed using the risk of bias assessment tool for non-randomised studies (RoBANs). A random effects model was used to estimate the pooled relative risk (RR) and standardised mean difference. The incidence of UKA revision for any reason was significantly higher in SONK than in MOA group (pooled RR = 1.83, p = 0.009). However, the risk of revision due to aseptic loosening and all- cause re-operation was not significantly different between the groups. Moreover, when stratified by the study quality, high quality studies showed similar risk of overall revision in SONK and MOA (p = 0.71). Subgroup analysis revealed worse survival of SONK, mainly related to high failure after uncemented UKA. Clinical outcomes after UKA were similar between SONK and MOA (p = 0.66). Cemented UKA has similar survival and clinical outcomes in SONK and MOA. Prospective studies designed specifically to compare the UKA outcomes in SONK and MOA are necessary

Several attempts have been made to treat medial compartment OA of the knee with mobile spacers. All have met with dismal failure. This presentation explores the history of attempts to treat OA in the younger knee with mobile spacers and explains why they were all doomed to fail. Sources of information for this presentation include the published peer reviewed literature, publically available documents, and an insiders view of some of the failed attempts to solve the problem of medial compartment OA with mobile spacers. All attempts to treat medial compartment OA of the knee with mobile spacers have failed. The unispacer has been a failure with a 60% revision rate at three years. The ABS intercushion had a 100% revision rate at one year and in many cases caused permanent damage to the host knees. The Salucartilage spacer was implanted in one patient only and failed within 48 hours. Mobile spacers do not work, are never likely to work, and are not indicated for the treatment of medial compartment osteoarthritis of the knee

There exists a variety of options for a medial compartment knee with osteoarthritis, specifically a unicompartmental knee, high tibial osteotomy, and total knee arthroplasty. This surgeon prefers a rotating platform posterior stabilised total knee to the unicompartmental knee. Unicompartmental knee arthroplasty (UKA) in younger patients is being performed with increasing frequency. While UKA is a powerful marketing tool because of its minimally invasive nature and quality of knee function that is superior to the total knee arthroplasty (TKA), it has tremendous drawbacks. These include: the selection criteria is very specific and the number of patients that fit in that category is small, there is a steep learning curve for the surgeon to perfect the technique, higher failure due to wear and loss of fixation, and unexplained pain. Based on level 1 and 2 evidence available it is not justified to do more UKAs at present when the results of a TKA are so successful.

While no one would argue the necessary role for the medical management of patients with early knee arthritis, significant controversy remains regarding the ideal treatment for a patient with bone-on-bone osteoarthritis who could equally be treated with a high tibial osteotomy, a uni-compartmental total knee, potentially a patello-femoral replacement if dealing with isolated patello-femoral disease or lastly, a complete total knee replacement. While clearly to date there has not been consensus on this issue, a review of the arguments, both pro and con, should be used as a guide to the surgeon in making this clinical judgment.

Patient Satisfaction - Many ardent supporters of uni-compartmental knee replacements espouse one of the principle benefits of the uni knee as much greater patient satisfaction. Unfortunately, what is never taken into account is the pre-selection bias that occurs in this patient population. Patients with the most minimal amount of arthritis and those with the greatest range of motion are pre-selected to undergo a uni-compartmental knee replacement compared to the more advanced arthritic knee with malalignment and more significant preoperative disability that will undergo a total knee replacement. Additionally the sources of data to draw the conclusions must be carefully analyzed. We must avoid using data from small series with unblinded patients performed by surgeons expert in the technique. Instead registry data, with its broad based applicability, is a much more logical source of information. Of significance, when over 27,000 patients were assessed regarding satisfaction following knee surgery; there was no difference in proportions of satisfied patients whether they had a total knee or a uni-compartmental knee.

Implant Longevity - Once again large prospective cohort data in the form of arthroplasty registries strongly favors total knee arthroplasty over uni-compartmental knee arthroplasty. The Swedish Knee Arthroplasty Registry demonstrated higher revision rates with uni's as compared with total knee replacements. In the Australian Joint Replacement Registry the cumulative 13-year percent revision rate for primary total knee replacements is 6.8% and for uni-compartmental knee replacements is 15.5%. Higher failure rates in uni-compartmental knee replacements seen in Australia has correlated to a significant decrease in the number of uni's being performed, which peaked at 15.1% in 2003 and in 2014 has reduced to 4.7%. There is a direct correlation to age, with younger patients having a significantly higher percentage of revision following uni-compartmental knee replacements (25% failure rate at 11 years if less than 55 years old). There is also tremendous variability in the success rate of the uni in the Australian Registry depending on the implant design (5-year cumulative revision rate range 5.0% to 18.9%), which is simply not seen in the total knee replacement population (5-year cumulative revision rate range 1.6% to 7.7%).

While one can perform the philosophical exercise of debating the merits of a total knee versus uni-compartmental knee, the evidence is overwhelming that in the hands of the masses a total knee replacement patient will have equal satisfaction to a uni-compartmental patient, and will enjoy a much lower probability of revision in the short term and in the long term.

Limited literature exists providing comprehensive assessment of complications following opening wedge high tibial osteotomy (OWHTO). We performed a retrospective study of local patients who underwent OWHTO for isolated medial compartment knee osteoarthritis from 1997–2013.

One hundred and fifteen patients met inclusion criteria. Mean follow-up = 8.4years. Mean age = 47 (range 32–62). Mean BMI = 29.1 (range 20.3–40.2). Implants used included Tomofix (72%), Puddu plate (21%) and Orthofix (7%) (no significant differences in age/ sex/ BMI). Wedge defects were filled with autologous graft (30%), Chronos (35%) or left empty (35%).

Five year survival rate (conversion to arthroplasty) = 80%. Overall complication rate = 31%. 25% of patients suffered 36 complications including minor wound infections (9.6%), major wound infections (3.5%), metalwork irritation necessitating plate removal (7%), non-union requiring revision (4.3%), vascular injury (1.7%), compartment syndrome (0.9%), and other minor complications (4%). No thromboembolic complications were observed.

A higher BMI (mean 34.2) was apparent in those patients suffering complications than those not (mean 26.9). No significant differences existed in complication rates relative to implant type, type of bone graft used or patient age at surgery.

Complications following OWHTO appear higher than previously reported in the literature; serious complications appear rare.

Contemporary indications for unicompartmental knee replacement (UKR) include bone on bone radiographic changes in the medial compartment with relatively preserved lateral and patellofemoral compartments. The role of MRI in identifying candidates for UKR is commonplace. The aim of this study was to assess the relationship between radiographic and MRI pre-operative grade and outcome following UKR. A retrospective analysis of medial UKR patients from 2017 to 2021. Inclusion criteria were medial UKR for osteoarthritis with pre-operative and post-operative Oxford Knee Scores (OKS), pre-operative radiographs and MRI. 89 patients were included. Whilst all patients had grade 4 ICRS scores on MRI, 36/89 patients had grade 3 KL radiographic scores in the medial compartment, 50/89 had grade 4 KL scores on the medial compartment. Grade 3 KL with grade 4 IRCS medial compartment patients had a mean OKS change of 17.22 (Sd 9.190) meanwhile Grade 4 KL had a mean change of 17.54 (SD 9.001), with no statistical difference in the OKS change score following UKR between these two groups (p=0.873). Medial bone oedema was present in all but one patient. Whilst lateral compartment MRI ICRS scores ranged from 1 to 4 there was no association with MRI score of the lateral compartment and subsequent change in oxford score (P value 0.458). Patellofemoral Compartment (PFC) MRI ICRS ranged from 0 to 4. There was no association between PFC ICRS score and subsequent change in oxford knee score (P value .276). Radiographs may under report severity of some medial sided knee osteoarthritis. We conclude that in patients with grade 3 KL score that would normally not be considered for UKR, pre-operative MRI might identify grade 4 ICRS scores and this subset of patients have equivalent outcomes to patients with radiographic Grade 4 KL medial compartment osteoarthritis

Introduction. We assessed the role of four different High Tibial osteotomies (HTOs) for medial compartment osteoarthritis of knee (MCOA): Medial Opening Wedge High Tibial Osteotomy (MOWHTO), Focal Dome Osteotomy with Ilizarov Fixator (FDO-I), intra-articular, Tibial Condylar Valgus Osteotomy with plating (TCVO-P) and intra-articular plus extra-articular osteotomy with Ilizarov(TCVO-I); in correcting three deformity categories: primary coronal plane varus measured by Mechanical Axis deviation (MAD), secondary intra-articular deformities measured by Condylar Plateau Angle (CPA) and Joint Line Convergence Angle (JLCA), and tertiary sagittal, rotational and axial plane deformities in choosing them. Materials and Methods. We retrospectively studied HTOs in 141 knees (126 patients). There were 58, 40, 26, and 17 knees respectively in MOWHTO, FDO-I, TCVO-P and TCVO-I. We measured preoperative (bo) And postoperative (po) deformity parameters. Results. Average age was 56.1, average follow-up was 44.6 months. Mean bo-MAD in MOWHTO, FDO-I, TCVO-P, and TCVO-I were 8.8, −14.7, −11.5, −30.8% respectively. po-MAD was close to Fujisawa point in all except TCVO-P (45.2%). CPA corrected from −4.9° to −1.4° (p=0.02)and JLCA from 5.6° to 3.2° (p=0.001); CPA was better corrected by Intra-articular osteotomies (p=0.01). Conclusions. MOWHTO corrects isolated mild primary varus deformities (bo-MAD≥ 0%). Primary varus (bo-MAD= −25% −0%) with associated tertiary sagittal, rotational, or axial deformities, without secondary intra-articular deformities needed FDO-I. Primary varus (bo-MAD= −25% −0%) with secondary intra-articular deformities, without tertiary deformities, corrected well with TCVO-P. TCVO-I corrects severe primary varus (bo-MAD< −25%) with large deformities in secondary and tertiary categories

Introduction. Unicompartmental knee arthroplasty (UKA) is a recognized procedure for treatment of medial compartment osteoarthritis. Patellofemoral (PF) joint degeneration is widely considered to be a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on consecutive patients who underwent UKA using the Repicci II® UKA prosthesis for medial compartment osteoarthritis. Methods. We prospectively collected data on 147 consecutive patients who underwent the Repicci II® UKA for medial compartment osteoarthritis. All operations were performed between July 1999 and September 2000 by the same surgeon. The status of the PF joint was assessed intra-operatively in all patients, and accordingly patients were divided into two groups, one group with a normal PF joint, and the second group with degenerative changes of the PF joint. Variables measured for outcome included the International Knee Society (IKS) score, limb alignment, and range of motion. Radiographs were assessed for progression of disease or failure of implant. The mean follow-up was 9.4 years (range: 5–10.7 years). Patients were reviewed initially at 2 weeks, and then at 6 months post-operatively. They were subsequently reviewed on an annual basis. All patients completed an IKS score preoperatively and at last follow-up. Age, gender, BMI, length of hospital stay, perioperative complications, all subsequent surgery, including revision of the prosthesis, and survivorship at 10 years was recorded, and results of the 2 groups compared. Results. A total of 147 patients were included in the study. None were lost to follow-up. Sixty nine had associated PF osteoarthritis (group A) while 78 patients had a normal PF compartment when assessed intra-operatively (group B). Post-operative outcomes of the two groups were compared using the ANCOVA analysis with adjustment for pre-operation values firstly, and adjusting also for gender, age, BMI and follow-up secondly. There were no significant differences in terms of IKS, alignment, and flexion between the two groups. However, patients in group B had significantly better extension post-operatively than patients in group A (p < 0.05). Conclusion. We concluded that damage to the articular cartilage of the patellofemoral joint to the extent of full-thickness cartilage loss is not a contraindication to the Repicci II® unicondylar knee arthroplasty for medial compartment osteoarthritis. However, extension is significantly improved post-operatively in those patients with minimal or no PF joint degenerative disease

Background. Unicompartmental knee arthroplasty provides a good alternative to total knee arthroplasty in patients with isolated medial compartment osteoarthritis. Reported ten-year survival for the Oxford medial unicompartmental knee arthroplasty is variable, ranging from 80.2% to 97.7% in the originator series. The aim of this study was to determine the survival and reasons for revision of the Oxford medial unicompartmental knee arthroplasty when performed at a specialist orthopaedic centre. Methods. Details of consecutive patients undergoing Oxford unicompartmental knee arthroplasty at our centre between January 2000 and December 2009 were collected prospectively. Failure of the implant was defined as conversion to total knee arthroplasty. Survival was determined using the Kaplan-Meier method. Results. There were 494 Oxford unicompartmental knee arthroplasties implanted in 425 patients for isolated medial compartment osteoarthritis. Mean age was 62.8 yrs (range 34.6-90.1 yrs) and 53.4% were female. During a mean follow-up time of 3.0 yrs (range 0.5-9.2 yrs), twenty-two knees (4.5%) were revised to a total knee arthroplasty. Reasons for revision were aseptic loosening of the femoral (n=8) or tibial component (n=2), undiagnosed pain (n=5), patellofemoral pain (n=2), infection (n=1), lateral meniscus tear (n=1), periprosthetic fracture (n=1), joint instability (n=1), and dislocation of meniscal bearing (n=1). Mean time to revision surgery from the primary procedure was 3.0 yrs. Eight-year survival for the cohort was 87.4%. The median pre-operative Oxford knee score was 62.5% which reduced to 27.7% at four years post-operatively. Conclusion. This study has demonstrated our revision rate for the Oxford unicompartmental knee replacement is comparable to independent series and national registry data. Post-operative function in patients not revised was good. The commonest reason for failure was aseptic component loosening which usually occurred within two to four years. Extended follow-up may therefore be beneficial in these patients so these cases are identified early and subsequently revised

Introduction:. The number of medial unicompartmental knee arthroplasties (UKA) performed over the last decade has increased by 30%, as studies have demonstrated improved knee kinematics, range of motion, and decreased perioperative morbidity versus total knee arthroplasty. However, concerns remain regarding the future risk of revision due to lateral compartment degeneration. In patients with a varus mechanical alignment and tibiofemoral subluxation secondary to medial compartment osteoarthritis, the femoral and tibial articular surfaces of the lateral compartment subsequently become incongruous, potentially increasing the focal contact stresses seen with loading. The purpose of this study is to evaluate whether the tibiofemoral congruence of the lateral compartment of the knee is improved following a medial UKA. Methods:. This study is a retrospective review of 192 consecutive medial UKAs included in an IRB-approved, single-surgeon database. All UKAs were performed using a robot-assisted surgical technique. Preoperative and postoperative standing, anteroposterior hip-to-ankle radiographs controlling for lower extremity rotation were performed from which the congruence of the lateral compartment was measured. The preoperative and postoperative degree of articular congruence (congruence index, CI) was calculated using an iterative closest point (ICP)-based software code (Matlab, MathWorks Inc., Natick, MA), specially developed to evaluate congruence of knee compartments. Following digitization of the articular surfaces of the femur and tibia, the code performs a rigid transformation that best aligns the articular surfaces and evaluates the current degree of articular congruence. A congruence index (CI) is then calculated, with a value of 1 indicating complete congruence, and a value of 0 indicating a 100% dislocation of the articular surfaces. A student's t-test was used to compare the preoperative and postoperative values of lateral compartment congruence. Results:. The mean, preoperative congruence index of the lateral compartment was 0.88 (± 0.1), which was improved to 0.93 (± 0.07), following implantation of a medial UKA (p < 0.001). Congruence of the lateral compartment was improved in 158 of the UKAs (83%), while 34 (17%) demonstrated a decrease in the congruence index postoperatively. Conclusion:. Implantation of a medial unicompartmental knee arthroplasty improves the articular surface congruence of the lateral compartment in the majority of patients with isolated, medial compartment osteoarthritis (Figure 1). We hypothesize that this factor, combined with a controlled undercorrection of the overall mechanical alignment, will improved load distribution across the lateral compartment, reduce the risk of focal contact stress points, and decrease the risk of subsequent osteoarthritic degeneration of the lateral compartment. Medial UKA not only resurfaces the medial compartment, but also may treat potential lateral compartment degeneration by improving congruence and load distribution

Introduction. Unicompartmental knee arthroplasty (UKA) currently experiences increased popularity. It is usually assumed that UKA shows kinematic features closer to the natural knee than total knee arthroplasty (TKA). Especially in younger patients more natural knee function and faster recovery have helped to increase the popularity of UKA. Another leading reason for the popularity of UKA is the ability to preserve the remaining healthy tissues in the knee, which is not always possible in TKA. Many biomechanical questions remain, however, with respect to this type of replacement. 25% of knees with medial compartment osteoarthritis also have a deficient anterior cruciate ligament [1]. In current clinical practice, medial UKA would be contraindicated in these patients. Our hypothesis is that kinematics after UKA in combination with ACL reconstruction should allow to restore joint function close to the native knee joint. This is clinically relevant, because functional benefits for medial UKA should especially be attractive to the young and active patient. Materials and Methods. Six fresh frozen full leg cadaver specimens were prepared to be mounted in a kinematic rig (Figure 1) with six degrees of freedom for the knee joint. Three motion patterns were applied: passive flexion-extension, open chain extension, and squatting. These motion patterns were performed in four situations for each specimen: with the native knee; after implantation of a medial UKA (Figure 2); next after cutting the ACL and finally after reconstruction of the ACL. During the loaded motions, quadriceps and hamstrings muscle forces were applied. Infrared cameras continuously recorded the trajectories of marker frames rigidly attached to femur, tibia and patella. Prior computer tomography allowed identification of coordinate frames of the bones and calculations of anatomical rotations and translations. Strains in the collateral ligaments were calculated from insertion site distances. Results. Knee kinematics and collateral ligament strains were quite close to the native situation after both UKA and ACL reconstruction for all motor tasks. Nevertheless, some statistically significant differences were detected, which may be relevant clinically and biomechanically. In general, insertion of a UKA led to a knee joint which was somewhat less adducted (Figure 3), with a medial femoral condyle located slightly higher, confirming previously published findings [2]. These effects were slightly reduced both after cutting as well as after reconstructing the ACL. The joint became somewhat less stable in the AP direction after insertion of a UKA and this instability persisted not only after cutting but even after reconstructing the ACL

Purpose. Patients with anterior cruciate ligament (ACL) deficiency and symptomatic medial compartment osteoarthritis (OA) present a challenge in management. These are often younger than typical primary OA patients and aspire to remain athletically active beyond simple ADLs. Combined ACL reconstruction and valgus tibial osteotomy (ACLHTO) is a well documented surgical option for patients deemed wither too young or too active for total knee arthroplasty. Unicompartmental knee arthroplasty (UKA) is an established surgical treatment for symptomatic medial osteoarthritis of the knee refractory to conservative management. A commonly cited contraindications is symptomatic ACL deficiency because of previous reports detailing premature failure through loosening of the tibial component. Improved results and endoscopic ACL reconstructive procedures have led to an enticing concept of combining ACL reconstruction with medial unicompartmental knee arthroplasty (ACLUKR) for those ACL-deficient medial osteoarthritic (OA) knees. We sought to compare the outcomes in 2 cohorts of patients who underwent either ACLHTO or ACLUKR for this clinical problem. Method. Patients presenting with symptomatic bone on bone medial compartment OA and concomitant ACL deficiency (clinical or asymptomatic) were evaluated for surgery after exhausting non operative management. Patients who were under 40 or had plans to return to high impact loading sports and/or who had more moderate OA were offered combined ACL – medial opening wedge tibia osteotomy as a surgical procedure of choice. Patients were considered for combined ACL Oxford replacement if they were primarily seeking pain relief and were not engaged or aspiring to return to high impact or pivoting sports. All cases but one were concurrent ACL with either HTO or UKR with autogenous hamstring grafts used in all but 2 cases. Results. Thirty of 34 consecutive cases were available for follow-up for a rate of 88%. The median ages for 14 cases of ACLUKR was 51 (range 43 60) whereas 16 patients with ACLHTO had median age 43.4 (range 32 −59). Median FU was 4.65 yrs with minimum 2 year follow up (range 2–8.3). Three of the cases were revision ACL cases all from previous Gore-Tex reconstructions. All but the first patient had concomitant ACL and Oxford unicompartmental knee replacement at 1 surgical sitting and are the subject of this report. The first patient had an autogenous patella bone tendon bone graft performed 6 months prior to the UKA. There were similar change scores for patients in both groups. For ACLUKR, WOMAC pain improvements from 48.1 10.2 SD preoperatively to 79.0 17 SD postop. For ACLHTO, WOMAC improvements from 55.1 13.2 SD preoperatively to 85.0 17 SD postop. To date there have been no cases of infection or bearing dislocation in the ACLUKR group. One patient in the ACLHTO group was revised to TKR for ongoing pain and postoperative flexion contracture. Patient activities ranged from ambulation to vigorous hiking, tennis, and downhill skiing in the UKR group whereas a few in the ACLHTO group were also running mid distances. Overall satisfaction was similar in both groups. Conclusion. ACL reconstruction can safely be combined with medial UKR. The procedure has been used in younger patients with a view toward bone preservation while anticipating need for future revision. Both cohorts showed similar improvements and can be considered. The choice should be geared toward patient athletic demand. While short term results are encouraging though longer term data are necessary to thoroughly evaluate the role of this procedure in patients with medial compartment osteoarthritis and ACL deficiency

Since 2005, the author has performed nearly 1000 Oxford medial unicompartmental arthroplasties (UKA) using a mobile bearing. The indications are 1) Isolated medial compartment osteoarthritis with ‘bone-on-bone’ contact, which has failed prior conservative treatment, 2) Medial femoral condyle avascular necrosis or spontaneous osteonecrosis, which has failed prior conservative treatment. Patients are recommended for UKA only if the following anatomic requirements are met: 1) Intact ACL, 2) Full thickness articular cartilage wear limited to the anterior half of the medial tibial plateau, 3) Unaffected lateral compartment cartilage, 4) Unaffected patellar cartilage on the lateral facet, 5) Less than 10 degrees of flexion deformity, 6) Over 100 degrees of knee flexion, and 7) Varus deformity not exceeding 15 degrees. Exclusion criteria for surgery are BMI of more than 30, prior high tibial osteotomy, and inflammatory arthritis. All cases were performed with a tourniquet inflated using a minimally-invasive incision with a quadriceps-sparing approach. Both femoral and tibial components were cemented. Most patients were discharged home the next morning; bilaterals usually stayed a day longer. We have previously described our results and the factors determining alignment. In a more recent study, we have compared the coronal post-operative limb alignment and knee joint line obliquity after medial UKA with a clinically and radiologically (less than Grade 2 medial OA) normal contralateral lower limb. In our series, we have had 1 revision for aseptic loosening of both components, conversion to TKRs in a patient with bilateral UKAs who developed rheumatoid arthritis 3 years later, and 9 meniscal dislocations. There have been no cases of wound infections and thromboembolism. We have reviewed our patients with a minimum 10-year follow-up which will be presented. The vast majority of our patients have been generally very satisfied with the results. Our study shows that most patients (who have no disease in the contralateral knee) regain their ‘natural’ alignment and joint line obliquity comparable to their contralateral limb. Over the past few years our percentage of UKAs has been steadily rising to about a third of our knee cases. UKA serves as a definitive procedure in the elderly. We see it as a suitable procedure in middle-aged patients who want an operation that provides a quick recovery, full function and range of motion, and near-normal kinematics, with the understanding that they have a small chance of conversion to a total knee arthroplasty in the future

INTRODUCTION. Patellofemoral compilcations are among the most frequently observed adverse events after total knee arthroplasty. The posterior location with Femoral component of conventional TKA in AP alignment cause paradoxical movement, but, guide motion TKA (Journey.2.BCS) with anterior post-cam remain a correct AP alignment. The purpose of this study was to investigate patellofemoral (PF) contact stress between Bi-Cruciate Substituting TKA (Journey.2.BCS) and CR TKA (Journey.CR). METHODS. We evaluated 22 knees with medial compartment osteoarthritis who underwent. Simultaneous bilateral TKA. The prospective randomized study was to measure intraoperative PF contact stress by a patellofemoral sensor (Kyowa Co., Ltd., Tokyo, Japan) comparing the identical Bi-Cruciate Substituting or CR Journey.2 total knee prostheses implanted bilaterally in the same patient. RESULTS. The PF contact stress showed significantly greater at CR TKA than at BCS TKA in 120 and 140 degrees of flextion (p=0.04, p=0.018). and showed no significant correlations with postoperative flextion angles. DISCUSSION AND CONCLUSION. In guide motion TKA, CR prosthesis increases PF contact stress than Bi-Cruciate Substituting prosthesis. The femoral rollback with medial pivot motion at CR TKA decreases more as the BCS TKA. Increased PF contact stress in guided motion TKA is not necessarily decrease postoperative flextion angle

Since 2005, the author has performed 422 Oxford medial unicompartmental arthroplasties (UKA) using a mobile bearing. There were 263 females and 119 males, (40 patients had bilateral UKAs) with a mean age of 62 years. The indications were: Isolated medial compartment osteoarthritis with ‘bone-on-bone’ contact, which had failed prior conservative treatment; Medial femoral condyle avascular necrosis or spontaneous osteonecrosis, which had failed prior conservative treatment. Patients were recommended UKA only if the following anatomic requirements were met: Intact ACL, Full thickness articular cartilage wear limited to the anterior half of the medial tibial plateau, Unaffected lateral compartment cartilage, Unaffected patellar cartilage on the lateral facet, Less than 10 degrees of flexion deformity, Over 100 degrees of knee flexion, Varus deformity not exceeding 15 degrees. Exclusion criteria for surgery were BMI of more than 30, prior high tibial osteotomy, and inflammatory arthritis. All cases were performed with a tourniquet inflated using a minimally-invasive incision with a quadriceps-sparing approach. Both femoral and tibial components were cemented. Rehabilitation consisted of teaching the patients 6 exercises to regain strength and range of motion, and weight-bearing as tolerated with a cane began from the evening of surgery. Most patients were discharged home the next morning; bilaterals usually stayed a day longer. We have previously described our results and the factors determining alignment. In a more recent study we have compared the coronal postoperative limb alignment and knee joint line obliquity after medial UKA with a clinically and radiologically (less than Grade 2 medial OA) normal contralateral lower limb. In our series of 423 cases, we have had 1 revision for aseptic loosening of both components, and 4 meniscal dislocations. There have been no cases of wound infections and thromboembolism. We are currently undertaking a review of the 2–10 year follow-up of our cases. The vast majority of our patients have been generally very satisfied with the results. Our study shows that most patients (who have no disease in the contralateral knee) regain their ‘natural’ alignment and joint line obliquity comparable to their contralateral limb. Over the past few years our percentage of UKAs has been steadily rising. UKA serves as a definitive procedure in the elderly. We see it as a suitable procedure in middle-aged patients who want an operation that provides a quick recovery, full function and range of motion, and near-normal kinematics, with the understanding that they have a small chance of conversion to a total knee arthroplasty in the future

Opening-wedge High Tibial Osteotomy (HTO) has been shown to be an effective procedure to treat mild to moderate osteoarthritis of the medial compartment of the knee in active individuals. It has also become a mandatory surgical adjunct to articular cartilage restoration when there is preoperative mal-alignment. However, its efficacy is directly correlated with the accuracy of the correction, which must be within 3° of the preoperative target. Achieving this goal is a significant challenge with conventional techniques. Therefore, computer-assisted navigation protocols have been developed; however, they do not adequately address the technical difficulties associated with this procedure. We present an integrated solution dedicated to the opening-wedge HTO. Advantages to the technique we propose include: 1) a minimum number of implanted bone trackers, 2) depth control of the saw, 3) improved 3-D accuracy in the location of the lateral tibial hinge, and 4) micrometric adjustment of the degree of correction. The proof of concept has been completed on all six specimens. The following key points have been validated: a) Compatibility with a minimally-invasive (5–6 cm) surgical incision b) The compact navigation station can be placed close to the operative field and manipulated through a sterile draping device c) Only two trackers are necessary to acquire the required landmarks and to provide 3-D control of the correction. These can be inserted within the surgical wound without any secondary incisions d) The optimised guide accurately controlled the external tibial hinge in all six cases e) The implant cavity could be milled effectively f) The distractor used to complete the desired realignment maintained stability of the distraction until final fixation with the PEEK implant g) The PEEK implant could be fixed to the tibia with excellent stability in a low-profile fashion. The solution presented here has the potential to help surgeons perform a medial opening-wedge HTO more safely and accurately. This will likely result in an increase in the number of HTOs performed for both isolated medial compartment osteoarthritis as well as for lower extremity realignment in association with cartilage restorative procedures

Opening wedge high tibial osteotomy (OWHTO) is a treatment option for medial compartment osteoarthritis of the knee in the young active adult. Limited evidence exists in the literature regarding return to activities following OWHTO. We performed a retrospective study of local patients who underwent OWHTO from 2005 – 2012 assessing post-operative return to sporting function. Patients with additional knee pathology, surgery or alternative issues affecting activity were excluded. 110 patients met inclusion criteria, 75 were successfully contacted. Mean improvement in pain score = 4.8/10 (95%CI 4.2 to 5.4, p<0.01). Mean pre-operative KOS-SAS score = 0.5/2, mean post-operative KOS-SAS score = 1.1/2, mean change in KOS-SAS score following OWHTO = 0.6 (95% CI 0.5 to 0.7, p<0.01). Mean pre-morbid Tegner score = 5.9/10, pre-operative = 2.7/10, post-operative = 4.2/10. Mean change in Tegner score following OWHTO = 1.5 (95% CI 1 to 1.9, p<0.01). Following OWHTO 25% of patients achieved pre-morbid Tegner scores. Patient BMI, age, type of implant or graft used had no significant effect on outcome. OWHTO can temporarily improve pain, activity and sporting levels in young patients with isolated medial compartment knee OA. Return to pre-morbid activity levels and even high level sports function is possible although not the norm

Purpose. The tibia first technique in unicompartmental knee arthroplasty (UKA) may have the advantage that surgeons can obtain a balanced flexion-extension gap. However, changes of the soft tissue tension during UKA has not been elucidated yet. The purpose of this study was to examine the correlation between the soft tissue tension before the femoral osteotomy and after the femoral component in place using the tensor in UKA. Methods. Thirty UKAs for isolated medial compartmental osteoarthritis or idiopathic osteonecrosis were assessed. The mean age was 71.8±8.5 years old (range: 58–85), and the average coronal plane femorotibial angle (FTA) was 181.2±3.2 degree preoperatively. All the patients received a conventional medial Zimmer Unicompartmental High Flex Knee System (Zimmer Inc, Warsaw, Ind). The actual values of the proximal and posterior femoral osteotomy were calculated by adding the thickness of the bone saw blades to the thickness of the bony cut. Using a UKA tensor which designed to facilitate intra-operative soft tissue tension throughout the range of motion (ROM), the original gap before the femoral osteotomy, the component gap after the femoral osteotomy, and component placement were assessed under 20 lb distraction forces. (Figure 1). Results. The mean actual thickness of the distal femoral osteotomy 6.5 ± 1.3 mm and the posterior femoral osteotomy was 7.4 ± 1.3 mm. The distal thickness of the Zimmer UKA was set to 6.5 mm and the mean posterior thickness of the prosthesis used in this study was 5.8 ± 0.3 mm. There is a positive correlation between the original and component gap throughout the ROM (R > 0.5). The original and component gap showed the same kinematic pattern from full extension to 90 degrees of knee flexion. However, the component gap showed significantly higher compared to the original gap after 120 degrees of knee flexion (p < 0.001). (Figure 2). Conclusions. Despite the fact that the component gap showed significantly higher compared to the original gap in deep flexion, there is a positive correlation between the original and component gap throughout the ROM. The discrepancy during deep flexion was due to the posterior design of the prosthesis that is designed to be thinner than the actual thickness of the posterior osteotomy in order to prevent flexion gap tightness. These results suggest that the tibia first technique with the tensor have the advantage that surgeons can predict final soft tissue tension before femoral osteotomies with the comprehension of the prosthetic design and help restore natural knee kinematics, potentially improving implant survival and functional outcomes