Abstract. Objectives. Hip instability following total hip arthroplasty in treatment of intracapsular neck of femur fractures is reported at 8–11%. Utilising the principle of a small articulation to minimize the problems of wear coupled with a large articulation, dual-mobility total hip arthroplasty prostheses stabilise the hip further than conventional fixed-bearing designs. The aim of this study is to compare the rate of dislocation and complication between standard fixed-bearing and dual-mobility prostheses for the treatment of intracapsular neck of femur fractures. Methods. A four-year retrospective review in a large district general hospital was completed. All cases of intracapsular neck of femur fractures treated with total hip arthroplasty were identified through the theatre logbooks. Patient's operative and clinical notes were retrospectively reviewed to collect data. Results. A total of 91 patients underwent total hip arthroplasty for intracapsular neck of femur fracture in the four-year period. 61.5% were dual-mobility design versus 28.5% had fixed-bearing implants. There were no statistical differences between patient group characteristics. Choice of implant was dependent on surgeon preference. There was a 0.0% dislocation rate in the dual-mobility group versus 8.6% in the fixed-bearing prosthesis group. All dislocations occurred in patients who underwent total hip arthroplasty with 36.0mm fixed-bearing prosthesis via posterior surgical approach. There was no statistical difference in mortality between both groups. Conclusion. There was an increasing trend of towards the use of dual-mobility prosthesis for fractured neck of femur within this department with excellent outcomes. Dual-mobility designs provide reduced dislocation rates in total hip arthroplasty in intracapsular neck of femur fractures compared to standard fixed-bearing designs at this institution. The authors recommend that all orthopaedic staff consider the use of dual-mobility prostheses in suitable patients and ensure trainees are suitably trained in use of dual-mobility designs. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

In this study, we examined the impact of dual-mobility (DM) versus fixed-bearing (FB) implants on outcomes following total hip arthroplasty (THA), a common and successful operation. We examined all-cause revision, revision due to dislocation, postoperative complications and functional scores in patients undergoing primary and revision THA. A systematic review was performed according to PRISMA guidelines, and was registered in PROSPERO (ID CRD42023403736). The Cochrane Library, Embase, MEDLINE, Web of Science, and Scopus were searched from inception to 12th March 2023. Eligible studies underwent meta-analysis and methodological assessment using the ROBINS-I tool. Data were pooled using a random-effects maximum-likelihood model. Eight comparative, non-randomised studies involving 2,810 DM implants and 3,188 FB implants were included. In primary THA, the difference in all-cause revision was imprecise (OR 0.82, 95% CI 0.25–2.72), whilst the DM cohort had a statistically significant benefit in revision due to dislocation (OR 0.08, 95% CI 0.02–0.28). In revision THA, the DM cohort showed significant benefit in all-cause revision (OR 0.57, 95% CI 0.31–1.05) and revision due to dislocation (OR 0.14, 95% CI 0.04–0.53). DM implants were associated with a lower incidence of implant dislocation and infection. Functional outcome analysis was limited due to underreporting. No intraprosthetic dislocations were observed. The results suggest that contemporary DM designs may be advantageous in reducing the risk of all-cause revision, revision due to dislocation, and postoperative complication incidence at mid-term follow-up. Further high-quality prospective studies are needed to evaluate the long-term performance of this design, especially in revision cases

Power production in the terminal stance phase is essential for propelling the body forward during walking and is generated primarily by ankle plantarflexion. Osteoarthritis (OA) of the ankle restricts joint range of motion and is expected to reduce power production at that ankle. This loss of power may be compensated for by unaffected joints on both the ipsilateral and contralateral limbs resulting in overloading of the asymptomatic joints. Total ankle arthroplasty (TAA) has been shown to reduce pain and has the potential to restore range of motion and therefore increase ankle joint power, which could reduce overloading of the unaffected joints and increase walking speed. The purpose of this study was to test the hypothesis that ankle OA causes a loss of power in the affected ankle, compensatory power changes in unaffected lower limb joints, and that TAA will increase ankle power in the repaired ankle and reduce compensatory changes in other joints. One hundred and eighty-three patients (86 men, 97 women with average ages 64.1 and 62.4 years respectively) requiring surgical intervention for ankle OA were prospectively enrolled. Implant selection of either a fixed (INBONE or Salto Talaris) or mobile (STAR) bearing implant was based on surgeon preference. Three-dimensional kinematics and kinetics were collected prior to surgery and one year post-operatively during self-selected speed level walking using an eight-camera motion capture system and a series of force platforms. Subject walking speed and lower extremity joint power during the last third of stance at the ankle, knee, and hip were calculated bilaterally and compared before and after surgical intervention across the entire group and by implant type (fixed vs. mobile), and gender using a series of ANOVAs (JMP SAS, Cary, NC), with statistical significance defined as p < 0 .05. There were no gender differences in age, walking speed, or joint power. All patients increased walking as a result of surgery (0.87 m/s±0.26 prior to surgery and 1.13 m/s±0.24 after surgery, p < 0 .001) and increased total limb power. Normalized to total power (which accounts for changes in speed and distribution of power production across joints), prior to surgery the affected ankle contributed 19%±10% of total power while the unaffected ankle contributed 42%±12% (P < 0 .001). After surgery, the affected ankle increased to 25%±9% of total power and the unaffected ankle decreased to 38%±9% of total (P < 0.001). Other joints showed no significant power changes following surgery. Fixed bearing implants provide greater surgical ankle power improvement (61% versus 29% increase, p < 0 .002). Much of that change was due to the fact that those that received fixed-bearing implants had significantly lower walking speed and power before surgery. Ankle OA reduced ankle power production, which was partially compensated for by the unaffected ankle. TAA increases walking speed and power at the affected ankle while lowering power production on the unaffected side. The modifications in power production could lead to increased physical activity and reduced overloading of asymptomatic joints

Converting UKA to TKA can be difficult, and specialised techniques are needed. Issues include bone loss, joint line approximation, sizing, and rotation. Determining the complexity of conversion preoperatively helps predict the need for augmentation, grafting, stems, or constraint. In a 2009 study from our center, 50 UKA revised to TKA (1997–2007) were reviewed: 9 modular fixed-bearing, 4 metal-backed nonmodular fixed-bearing, 8 resurfacing onlay, 10 all-polyethylene step-cut, and 19 mobile bearing designs; 5 knees failed due to infection, 5 due to wear and/or instability, 10 for pain or progression of arthritis, 8 for tibial fracture or severe subsidence, and 22 due to loosening of either one or both components. Insert thickness was no different between implants or failure modes. Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Reestablishing the joint line, ligamentous balance, and durable fixation are critical to assuring a primary outcome. In a 2013 multicenter study of 3 institutions including ours, a total of 175 revisions of medial UKA in 168 patients (average age: 66 years) performed from 1995 to 2009 with a minimum 2-year clinical follow-up were reviewed. The average time from UKA to revision TKA was 71.5 months (2–262). The four most common reasons for failure were femoral or tibial loosening (55%), progressive arthritis of the lateral or patellofemoral joints (34%), polyethylene failure (4%) and infection (3%). Mean follow-up after revision was 75 months. Nine of 175 knees (4.5%) were subsequently revised at an average of 48 months (6–123). The average Knee Society pain and function score increased to 75 and 66, respectively. In the present series, the re-revision rate after revision TKA from UKA was 4.5% at an average of 75 months. In a current study from our center, 184 patients (193 UKA) underwent revision procedures (1996–2015) with minimum 2-year follow-up. Mean age was 63.5 (37–84) years, body mass index was 32.3 (19–57) kg/m. 2. , and interval after UKA was 4.8 (0–35) years. Most prevalent indications for revision were aseptic loosening (42%), arthritic progression (20%) and tibial collapse (14%). At 6.1 years mean follow-up (2–20), 8 knees (4.1%) have required re-revision involving any part, which is similar to what we recently reported at 5.5 years in a group of patients who underwent primary TKA (6 of 189; 3.2%), and much lower than what we observed at 6.0 years in a recent report of patients who underwent aseptic revision TKA (35 of 278; 12.6%). In the study group, Knee Society clinical and function scores improved from 50.8 and 52.1 preoperatively to 83.4 and 67.6 at most recent evaluation, respectively. Re-revisions were for aseptic loosening (3), instability (2), arthrofibrosis (2), and infection (1). Compared to published individual institution and national registry data, re-revision rates of failed UKA are equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA

Converting UKA to TKA can be difficult, and specialised techniques are needed. Issues include bone loss, joint line approximation, sizing, and rotation. Determining the complexity of conversion pre-operatively helps predict the need for augmentation, grafting, stems, or constraint. In a 2009 study from our center, 50 UKA revised to TKA (1997–2007) were reviewed: 9 implants (18%) were modular fixed-bearing, 4 (8%) were metal-backed nonmodular fixed-bearing, 8 (16%) were resurfacing onlay, 10 (20%) were all-polyethylene step-cut, and 19 (38%) were mobile bearing designs; 5 knees (10%) failed due to infection, 5 (10%) due to wear and/or instability, 10 (20%) for pain or progression of arthritis, 8 (16%) for tibial fracture or severe subsidence, and 22 (44%) due to loosening of either one or both components. Insert thickness was no different between implants (P=0.23) or failure modes (P=0.27). Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Failure mode was predictive of complexity. Reestablishing the joint line, ligamentous balance, and durable fixation are critical to assuring a primary outcome. In a 2013 multicenter study of 3 institutions including ours, a total of 175 revisions of medial UKA in 168 patients (81 males, 87 females; average age of 66 years) performed from 1995 to 2009 with a minimum of 2-year clinical follow-up were reviewed. The average time from UKA to revision TKA was 71.5 months (range: 2 months to 262 months). The four most common reasons for failure of the UKA were femoral or tibial loosening (55%), progressive arthritis of the lateral or patellofemoral joints (34%), polyethylene failure (4%) and infection (3%). Mean follow-up after revision was 75 months. Nine of 175 knees (4.5%) were subsequently revised at an average of 48 months (range 6 months to 123 months.) The rate of revision was 1.23 revisions per 100 observed component years. The average Knee Society pain and function score increased to 75 and 66, respectively. In the present series, the re-revision rate after revision TKA from UKA was 4.5 % at an average of 75 months or 1.2 revisions per 100 observed component years. In a current study from our center, 174 patients (180 UKA) underwent revision procedures (1996–2017). Most prevalent indications for revision were aseptic loosening (45%) arthritic progression (17%) and tibial collapse (13%). At 4 years mean follow-up, 5 knees (2.8%) have required re-revision involving any part, which is similar to what we recently reported at 5.5 years in a group of patients who underwent primary TKA (6 of 189; 3.2%), and much lower than what we observed at 6.0 years in a recent report of patients who underwent aseptic revision TKA (35 of 278; 12.6%). Compared to published individual institution and national registry data, re-revision of a failed UKA is equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA

Converting UKA to TKA can be difficult, and specialised techniques are needed. Issues include bone loss, joint line approximation, sizing, and rotation. Determining the complexity of conversion pre-operatively helps predict the need for augmentation, grafting, stems, or constraint. In a 2009 study from our center, 50 UKA revised to TKA (1997–2007) were reviewed: 9 implants (18%) were modular fixed-bearing, 4 (8%) were metal-backed nonmodular fixed-bearing, 8 (16%) were resurfacing onlay, 10 (20%) were all-polyethylene step-cut, and 19 (38%) were mobile bearing designs; 5 knees (10%) failed due to infection, 5 (10%) due to wear and/or instability, 10 (20%) for pain or progression of arthritis, 8 (16%) for tibial fracture or severe subsidence, and 22 (44%) due to loosening of either one or both components. Insert thickness was no different between implants (P=0.23) or failure modes (P=0.27). Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Failure mode was predictive of complexity. Reestablishing the joint line, ligamentous balance, and durable fixation are critical to assuring a primary outcome. In a 2013 multicenter study of 3 institutions including ours, a total of 175 revisions of medial UKA in 168 patients (81 males, 87 females; average age of 66 years) performed from 1995 to 2009 with a minimum of 2-year clinical follow-up were reviewed. The average time from UKA to revision TKA was 71.5 months (range 2 months to 262 months). The four most common reasons for failure of the UKA were femoral or tibial loosening (55%), progressive arthritis of the lateral or patellofemoral joints (34%), polyethylene failure (4%) and infection (3%). Mean follow-up after revision was 75 months. Nine of 175 knees (4.5%) were subsequently revised at an average of 48 months (range 6 months to 123 months). The rate of revision was 1.23 revisions per 100 observed component years. The average Knee Society pain and function score increased to 75 and 66, respectively. In the present series, the re-revision rate after revision TKA from UKA was 4.5% at an average of 75 months or 1.2 revisions per 100 observed component years. Compared to published individual institution and national registry data, re-revision of a failed UKA is equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA

Converting unicompartmental knee arthroplasty (UKA) to total knee arthroplasty can be difficult, and specialised techniques are needed. Issues include bone loss, joint-line, sizing, and rotation. Determining the complexity of conversion preoperatively helps predict the need for augmentation, grafting, stems, or constraint. We examined insert thickness, augmentation, stem use, and effect of failure mode on complexity of UKA conversion. Fifty cases (1997–2007) were reviewed: 9 implants (18%) were modular fixed-bearing, 4 (8%) were metal-backed nonmodular fixed-bearing, 8 (16%) were resurfacing onlay, 10 (20%) were all-polyethylene step-cut, and 19 (38%) were mobile bearing designs; 5 knees (10%) failed due to infection, 5 (10%) due to wear and/or instability, 10 (20%) for pain or progression of arthritis, 8 (16%) for tibial fracture or severe subsidence, and 22 (44%) due to loosening of either one or both components. Complexity was evaluated using analysis of variance and chi-squared 2-by-k test (80% power; 95% confidence interval). Insert thickness was no different between implants (P=0.23) or failure modes (P=0.27). Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Failure mode was predictive of complexity. Reestablishing the joint-line, ligamentous balance, and durable fixation are critical to assuring a primary outcome

Purpose. The mobile-bearing total knee arthroplasty was designed to increase the contact area with the polyethylene bearing, through the functional range of motion, and subsequently decrease the wear rate previously seen in fixed-bearing implants. In the literature there is no clear clinical advantage between the different designs in the short to mid-term follow-up. The purpose of this study was to compare the results between a cruciate retaining mobile-bearing design (SAL II, Sulzer) and two cruciate retaining fixed-bearing designs (AMK, Depuy, and the Genesis II, Smith and Nephew). Method. Ninety patients were randomised to receive either the mobile-bearing or one of the two fixed-bearing designs between 2000 and 2002. Patients were evaluated preoperatively and postoperatively using the WOMAC and the SF-12, both of which are validated scores. One patient was withdrawn due to dementia before three months and eleven patients died. Two patients were revised due to infection (both had received the SAL II). One patient was revised for aseptic loosening and one patient was revised for pain (both had received the Genesis II). Of the 74 patients (77 knees) that remain, they were last seen on average 6.4 years (2–10) after their surgery. Their average age at the surgery was 69.2 years (52–81). Results. There was no statistically significant difference between the change scores (postoperative score minus preoperative score) for each of the outcome measures between the mobile-bearing and the two fixed-bearing designs. Conclusion. In conclusion, after mid-term follow-up there is no clinical difference between a cruciate retaining mobile-bearing design and two cruciate retaining fixed-bearing designs

Introduction. In total knee arthroplasty, the alignment of leg depends on the alignment of the component. In unicompartmental knee arthroplasty, it is determined by the thickness of the implant relative to the bone excised mostly. After initial scepticism, UKA is increasingly accepted as a reliable procedure for unicompartmental knee osteoarthritis with the improvements in implant design, surgical technique and appropriate patient selection. Recently, computer assisted UKA is helpful in accuracy and less invasive procedure. But, fixed bearing or mobile bearing in UKA is still controversy. We compared the early clinical and radiological results of robot-assisted unicompartmental knee arthroplasty using a fixed bearing design versus a mobile type bearing design. Materials and Methods. A data set of 50 cases of isolated compartmental degenerative disease that underwent robot-assisted UKA using a fixed bearing design were compared to a data set of 50 cases using a mobile bearing type design. The operations were performed by one-senior author with the same robot system. The clinical evaluations included the Knee Society Score (knee score, functional score) and postoperative complications. The radiological evaluations was assessed by 3-foot standing radiographs using the technique of Kennedy and White to determine the mechanical axis and femoro-tibial angle for knee alignment. Operative factors were evaluated including length of skin incision, operation time, blood loss, hospital stay and intraoperative complications. Results. There were no statistically significant differences in operation time, skin incision size, blood loss and hospital stay. (p > 0.05) There were no significant differences in Knee Society Scores at last follow up. An average preoperative femorotibial alignment was varus alignment of −1° in both groups. Postoperative patients with fixed-bearing implants had an average +2.1° valgus and the patients with mobile bearing implants had +5.4° valgus in femorotibial alignment, which was different.(p<0.05) There was one case of medial tibia plateau fracture in fixed bearing group in 3 months postoperatively. And there were one case of liner dislocation with unstable knee in 6 weeks postoperatively and one case of femoral component loosening in 1 year postoperatively in mobile bearing group. There was no intraoperative complication. The average preoperative knee score was 45.8, which improved to 89.5 in fixed bearing group and 46.5, which improved to 91.2 in mobile bearing group at last followup. The average preoperative function score was 62.4 which improved to 86.5 in fixed bearing group and 60.7 which improved to 88.2 in mobile bearing group at last followup. Conclusion. In ourearly experience, two types of bearing of robot-assisted UKA groups showed no statistical differences in clinical assessment but there was statistical difference in postoperative radiological corrected alignment. But in aspect of early complications, we think that mobile bearing seems to be requiring more attention in surgery

Introduction: Many types of prosthesis are currently used for total knee arthroplasty. Controversy exists as to whether mobile-bearing or fixed-bearing implants make any difference in achieving earlier or better movement, resulting in earlier patient discharge. Aim: The purpose of our study was to compare the post-operative recovery and early results of 4 different mobile- and fixed-bearing knee implants. Method: Between 19/7/05 and 15/6/07 202 knees were implanted into 190 patients. Patients were randomly selected for 1 of 4 implants (2 mobile-bearing, 2 fixed-bearing). Outcomes were assessed using the American Knee Society Score (AKSS) and range-of-movement, both pre-operatively and at 1 year post-operatively. Range-of-movement was also recorded on discharge. Results: No significant difference was shown between the individual implant groups and the actual mean pre-operative and 1 year post-operative AKSS knee or functional scores or the change in knee score. A difference was noted however in the change in functional score between the 2 mobile-bearing knees (p=0.03). No significant difference was found between the 4 individual implants or the type of bearing used (mobile- or fixed-bearing) with regards to gender, age, length of stay or range-of-movement. Conclusion: The type of implant used does not affect the early or 12 month outcomes in relation to range-of-movement, length of stay or AKSS knee scores

Aims

The aim of this study was to determine whether obesity had a detrimental effect on the long-term performance and survival of medial unicompartmental knee arthroplasties (UKAs).

Aims

The aims were to assess whether joint-specific outcome after total knee arthroplasty (TKA) was influenced by implant design over a 12-year follow-up period, and whether patient-related factors were associated with loss to follow-up and mortality risk.

Introduction and Aims: Fixed bearing and mobile bearing knee designs are currently used in clinical practice with little evidence based research available to determine superiority of one system. The purpose of this study was to compare the results between a cruciate retaining mobile bearing and two cruciate retaining fixed bearing total knee prostheses. Method: We performed a prospective, randomised, blinded clinical trial to compare a mobile bearing to two standard fixed-bearing implants. We evaluated the short- and long-term outcomes of the SAL. ®. (Sulzer) mobile bearing versus the AMK. ®. (Depuy) and Genesis II. ®. (Smith & Nephew) fixed bearing, total knee joint replacements. Ninety patients were randomised to receive one of the three prostheses. Patients were evaluated pre-operatively, at three, 12 months and annually thereafter. Patient demographics, radiographs, and multiple outcome measures (WOMAC, SF-12 and the Knee Society Clinical Rating System) were evaluated. A single observer was used to measure range of motion scores. Results and Discussion: No patients were lost to follow-up. One patient was withdrawn due to dementia before three months, one patient died prior to the two-year follow-up, and one patient was revised for infection at six months, leaving 87 patients at an average follow-up of 3.37 years (range 2.91–4.44 years). There were no significant differences in any outcome measures or radiographic findings. There were no differences in KSCRS at two years (SAL – 167, AMK – 158, GenesisII – 166 ). There were no differences in WOMAC scores or SF-12 survey scores. There were no differences in knee flexion at two years (SAL – 117. °. , AMK – 115. °. , GenesisII – 118. °. ). Therefore, no differences in multiple outcome measures were seen between a cruciate retaining mobile bearing and two cruciate retaining fixed bearing total knee prostheses. Conclusion: In this prospective randomised clinical trial no differences could be seen between a mobile bearing and two fixed bearing designs at a minimum of two years follow-up. Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity

Aims

The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively.

Aims

The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery.

Aims

There are comparatively few randomized studies evaluating knee arthroplasty prostheses, and fewer still that report longer-term functional outcomes. The aim of this study was to evaluate mid-term outcomes of an existing implant trial cohort to document changing patient function over time following total knee arthroplasty using longitudinal analytical techniques and to determine whether implant design chosen at time of surgery influenced these outcomes.

Objectives

Elevated proximal tibial bone strain may cause unexplained pain, an important cause of unicompartmental knee arthroplasty (UKA) revision. This study investigates the effect of tibial component alignment in metal-backed (MB) and all-polyethylene (AP) fixed-bearing medial UKAs on bone strain, using an experimentally validated finite element model (FEM).

Partial knee arthroplasty (PKA), either medial or lateral unicompartmental knee artroplasty (UKA) or patellofemoral arthroplasty (PFA) are a good option in suitable patients and have the advantages of reduced operative trauma, preservation of both cruciate ligaments and bone stock, and restoration of normal kinematics within the knee joint. However, questions remain concerning long-term survival. The goal of this review article was to present the long-term results of medial and lateral UKA, PFA and combined compartmental arthroplasty for multicompartmental disease. Medium- and long-term studies suggest reasonable outcomes at ten years with survival greater than 95% in UKA performed for medial osteoarthritis or osteonecrosis, and similarly for lateral UKA, particularly when fixed-bearing implants are used. Disappointing long-term outcomes have been observed with the first generation of patellofemoral implants, as well as early Bi-Uni (ie, combined medial and lateral UKA) or Bicompartmental (combined UKA and PFA) implants due to design and fixation issues. Promising short- and med-term results with the newer generations of PFAs and bicompartmental arthroplasties will require long-term confirmation.

Cite this article: Bone Joint J 2015;97-B(10 Suppl A):9–15.