The National Joint Registry (NJR) for England & Wales provides a useful reference for hospitals to assess and compare their current practice with national figures. We aimed to identify patient and surgical factors at time of primary total knee arthroplasty (TKA) responsible for the revision. A retrospective case note review was performed of all revision TKAs performed at Musgrove Park Hospital 2005–2010. Exclusion criteria included primary TKA performed elsewhere. 38 TKAs and 13 unicompartmental knee arthroplasties (UKAs) were revised. Mean time to revision was 1.8 years and 2.1 years respectively. Reason for revision was pain or disease progression in 54% revised UKAs and infection in 53% revised TKAs. 35% infected cases were therapeutically anticoagulated, 75% ASA 3 and 50% had a BMI >30. No problems were identified with surgeon grade or level of supervision. 5 cases of revision were of a trial primary prosthesis. There were large numbers of high risk patients (increased BMI, ASA grade or on anticoagulants), which may contribute to increased infection rates and subsequent revision. We suggest avoiding trial prostheses and recommend delaying anticoagulation reintroduction until the wound is fully healed. This information may be useful for aiding with patient selection and consent

The main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS). Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years. An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants’ displacement values were always 2 mm during the first 6 months, and then, two different trends were noticed in revised and non-revised implants. MTPM increase between 1 and 2 years of follow-up in non-revised UKAs was always 0.2 mm, whereas it was [0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p 0.001). Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons

Unlike tri-compartmental arthroplasty, unicompartmental knee arthroplasties (UKAs) correct only osteochondral condylar defects and do not include any ligament balancing. Pre-operative deformities of more than 20° strongly suggest that UKA is not indicated. Best results are generally obtained by avoiding hypercorrection and not exceeding 5° of residual deformity post-operatively. Since 1997, 112 UKAs have been implanted. We performed tibial osteotomies with respect to tibial plateau inclination in the frontal plane (metaphyseal axis). Our patients were pre-operatively studied and then re-evaluated after a mean follow-up of 4 years. We used the GIUM (Gruppo Italiano Utilizzatori Monocompartimentali) scoring system. Pre-operative and post-operative radiograms from all patients were collected, and then we correlated the amount of correction of lower limb mechanical axis with GIUM score for each patient. Mean pre-operative mechanical axis of the lower limb showed a varus deformity of 7.43°, whereas post-operative values averaged 5.56° of varus deformity, with a minimal valgus correction of the deformity. Thus, correction of angular deformity was statistically negligible (p> 0.5). Mean pre-operative GIUM score was 20.3, whereas mean post-operative score was 71.6 (p< 0.001). Correlation between entity of correction and GIUM score was significant (r=0.76). The amount of angular correction of the mechanical axis of the lower limb was statistically significant in influencing functional outcomes (p< 0.05). The best results are obtained by correcting excessively valgus knees to a physiologic range, while varus knees have to be minimally corrected. The worst results are obtained with greatest modifications of the mechanical axis of the lower limb

Cementless knee arthroplasty has seen a recent resurgence in popularity due to conceptual advantages, including improved osseointegration providing biological fixation, increased surgical efficiency, and reduced systemic complications associated with cement impaction and wear from cement debris. Increasingly younger and higher demand patients are requiring knee arthroplasty, and as such, there is optimism cementless fixation may improve implant survivorship and functional outcomes.

Compared to cemented implants, the National Joint Registry (NJR) currently reports higher revision rates in cementless total knee arthroplasty (TKA), but lower in unicompartmental knee arthroplasty (UKA). However, recent studies are beginning to show excellent outcomes with cementless implants, particularly with UKA which has shown superior performance to cemented varieties. Cementless TKA has yet to show long-term benefit, and currently performs equivalently to cemented in short- to medium-term cohort studies. However, with novel concepts including 3D-printed coatings, robotic-assisted surgery, radiostereometric analysis, and kinematic or functional knee alignment principles, it is hoped they may help improve the outcomes of cementless TKA in the long-term. In addition, though cementless implant costs remain higher due to novel implant coatings, it is speculated cost-effectiveness can be achieved through greater surgical efficiency and potential reduction in revision costs. There is paucity of level one data on long-term outcomes between fixation methods and the cost-effectiveness of modern cementless knee arthroplasty.

This review explores recent literature on cementless knee arthroplasty, with regards to clinical outcomes, implant survivorship, complications, and cost-effectiveness; providing a concise update to assist clinicians on implant choice.

Cite this article: Bone Jt Open 2021;2(1):48–57.

Aims

Unicompartmental knee arthroplasty (UKA) has become a popular method of treating knee localized osteoarthritis (OA). Additionally, the posterior cruciate ligament (PCL) is essential to maintaining the physiological kinematics and functions of the knee joint. Considering these factors, the purpose of this study was to investigate the biomechanical effects on PCL-deficient knees in medial UKA.

Objectives

Patient-specific (PS) implantation surgical technology has been introduced in recent years and a gradual increase in the associated number of surgical cases has been observed. PS technology uses a patient’s own geometry in designing a medical device to provide minimal bone resection with improvement in the prosthetic bone coverage. However, whether PS unicompartmental knee arthroplasty (UKA) provides a better biomechanical effect than standard off-the-shelf prostheses for UKA has not yet been determined, and still remains controversial in both biomechanical and clinical fields. Therefore, the aim of this study was to compare the biomechanical effect between PS and standard off-the-shelf prostheses for UKA.

The February 2015 Knee Roundup³⁶⁰ looks at: Intra-operative sensors for knee balance; Mobile bearing no advantage; Death and knee replacement: a falling phenomenon; The swings and roundabouts of unicompartmental arthroplasty; Regulation, implants and innovation; The weight of arthroplasty responsibility!; BMI in arthroplasty