Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) have both been shown to be effective treatments for osteoarthritis (OA) of the knee. Many studies have compared the outcomes of the two treatments, but less so with the use of robotics, or individualized TKA alignment techniques. Functional alignment (FA) is a novel technique for performing a TKA and shares many principles with UKA. Our aim was to compare outcomes from a case-matched series of robotic-assisted UKAs and robotic-assisted TKAs performed using FA. From a prospectively collected database between April 2015 and December 2019, patients who underwent a robotic-assisted medial UKA (RA-UKA) were case-matched with patients who had undergone a FA robotic-assisted TKA (RA-TKA) during the same time period. Patients were matched for preoperative BMI, sex, age, and Forgotten Joint Score (FJS). A total of 101 matched pairs were eligible for final review. Postoperatively the groups were then compared for differences in patient-reported outcome measures (PROMs), range of motion (ROM), ability to ascend and descend stairs, and ability to kneel.Aims
Methods
Functional alignment (FA) in total knee arthroplasty (TKA) aims to achieve balanced gaps by adjusting implant positioning while minimizing changes to constitutional joint line obliquity (JLO). Although FA uses kinematic alignment (KA) as a starting point, the final implant positions can vary significantly between these two approaches. This study used the Coronal Plane Alignment of the Knee (CPAK) classification to compare differences between KA and final FA positions. A retrospective analysis compared pre-resection and post-implantation alignments in 2,116 robotic-assisted FA TKAs. The lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were measured to determine the arithmetic hip-knee-ankle angle (aHKA = MPTA – LDFA), JLO (JLO = MPTA + LDFA), and CPAK type. The primary outcome was the proportion of knees that varied ≤ 2° for aHKA and ≤ 3° for JLO from their KA to FA positions, and direction and magnitude of those changes per CPAK phenotype. Secondary outcomes included proportion of knees that maintained their CPAK phenotype, and differences between sexes.Aims
Methods
The aim of this study was to report patient and clinical outcomes following robotic-assisted total knee arthroplasty (RA-TKA) at multiple institutions with a minimum two-year follow-up. This was a multicentre registry study from October 2016 to June 2021 that included 861 primary RA-TKA patients who completed at least one pre- and postoperative patient-reported outcome measure (PROM) questionnaire, including Forgotten Joint Score (FJS), Knee Injury and Osteoarthritis Outcomes Score for Joint Replacement (KOOS JR), and pain out of 100 points. The mean age was 67 years (35 to 86), 452 were male (53%), mean BMI was 31.5 kg/m2 (19 to 58), and 553 (64%) cemented and 308 (36%) cementless implants.Aims
Methods
Robotic Assisted Arthroplasty (RAA) is increasingly proliferative in the international orthopaedic environment. Traditional bibliometric methods poorly assess the impact of surgical innovations such as robotic technology. Progressive Scholarly Acceptance (PSA) is a new model of bibliographic analysis which quantitatively evaluates the impact of robotic technology in the orthopaedic scientific community. A systematic literature search was conducted to retrieve all peer-reviewed, English language publications studying robotic assisted hip and knee arthroplasty between 1992 and 2017. Review articles were excluded. Articles were classified as either “initial investigations” or “refining studies” according to the PSA model, described by Schnurman and Kondziolka. The PSA end-point is defined as the point in time when the number of studies focussed on refining or improving a novel technique (RAA) outnumbers the number of initial studies assessing its efficacy.Introduction and aims
Methods
The International Orthopaedic community is eagerly adopting Robotic Assisted Arthroplasty (RAA) technology. However, the evidence for the benefits of this technology are unproven and at best equivocal. This study is a comprehensive bibliometric analysis of all published research in the field of RAA. A systematic literature search was conducted to retrieve all peer-reviewed, English language, publications studying robot- assisted hip and knee arthroplasty between 1992 and 2017. Review articles were excluded. Articles were classified by type of study and level of evidence according to the Oxford Centre for Evidence-based Medicine (OCEBM) Levels of Evidence System. The number of citations, authorship, year of publication, journal of publication, and country and institution of origin were also recorded for each publication.Introduction and aims
Methods
Hydroxyapatite coatings for uncemented fixation in total knee
arthroplasty can theoretically provide a long-lasting biological
interface with the host bone. The objective of this study was to
test this hypothesis with propriety hydroxyapatite, peri-apatite,
coated tibial components using component migration measured with radiostereometric
analysis over two years as an indicator of long-term fixation. A total of 29 patients at two centres received uncemented PA-coated
tibial components and were followed for two years with radiostereometric
analysis exams to quantify the migration of the component.Aims
Patients and Methods
The Accolade II taper stem incorporates design features which maximize proximal stem fit and bone contact and avoids more distal taper engagement which has been shown to be problematic. RSA was used in this study to analyze stem micromotion to 2 years post-surgery, providing an indication of long-term fixation. Pain, function and health-related quality of life were also compared before and after total hip arthroplasty (THA.) This prospective, single centre case-series enrolled 35 patients into Parts A and B. The first 5 subjects were recruited to Part A of the study (learning curve), the subsequent 30 patients to part B. Radiopaque tantalum beads were inserted intra-operatively into each patient, with RSA radiographs taken immediately post-operatively, and at 3, 6, 12 and 24 months. These radiographs were digitized to DICOM file format and exported, allowing for independent analysis using the UmRSA system. Three Patient Reported Outcome Measurements; WOMAC, EQ-5D-3L and VAS pain were collected pre-operatively and at 6, 12 and 24 month intervals for all patients.Introduction
Method
Immediate post-operative stability of a cementless hip design is one of the key factors for osseointegration and therefore long-term success [1]. This study compared the initial stability of a novel, shortened, hip stem to a predicate standard tapered wedge stem design with good, long-term, clinical history. The novel stem is a shortened, flat tapered wedge stem design with a shape that was based on a bone morphology study of 556 CT scans to better fit a wide array of bone types [2]. Test methods were based on a previous study [3]. Five stems of the standard tapered wedge design (Accolade, Stryker Orthopaedics, Mahwah, NJ) and the novel stem (Accolade II, Stryker Orthopaedics, Mahwah, NJ) were implanted into a homogenous set of 10 synthetic femora (Figure 1) utilizing large left fourth generation composite femurs (Sawbones, Pacific Labs, Seattle, WA). The six degrees-of-freedom (6 DoF) motions of the implanted stems were recorded under short-cycle stair-climbing loads. Minimum head load was 0.15 kN and the maximum load varied between 3x Body Weights (BW) and 6 BW. Loading began with 100-cycles of “normal” 3 BW and was stepped up to 4 BW, 5 BW & 6 BW for 50-cycles each. Prior to each load increase, 50 cycles of 3 BW loading was applied. This strategy allowed a repeatable measure of cyclic stability after each higher load was applied. The 6 DoF micromotion data, acquired during the repeated 3 BW loading segments, were reduced to four outcome measures: two stem migrations (retroversion and subsidence at minimum load) and two cyclic motions (cyclic retroversion and cyclic subsidence). Data were analyzed using repeated measures ANOVA with a single between-subjects factor (stem type) and repeated measures defined by load-step (3 BW, 4 BW, 5 BW 6 BW).INTRODUCTION
METHODS
Over the past ten years we have seen a move to less invasive surgical approaches and simplification of OR procedures; hence, there has been a renewed interest in the use of rectangular wedge-taper design hip stems. I present a personal series of over five hundred Accolade (Stryker) stems with a high (6%) early failure rate. Cases are drawn from a personal database. These patients presented with either pain or difficulty with stair-climbing. Several remain asymptomatic, but radiographs are early identical in all cases. Impressive radio-lucent and sclerotic lines are seen on the lateral radiograph in Gruen zones VIII and XIV at between three and six months, and later appear in Gruen I. Most occurred in type A or AA bone. These failures are interesting as they are due to rotational loosening, not axial subsidence. To date, 6 of 12 have been revised, all showing complete lack of ingrowth to proximal porous coating. Rectangular wedge-taper design stems have enjoyed high success rates in several published series. However, the author believes that the use of this stem in Type A or AA bone leads to preferential distal (diaphyseal) taper engagement, which negates proximal (meta-diaphyseal) taper engagement, and predisposes the stem to rotational micromotion, failure of ingrowth, and subsequent loosening. To our knowledge, this is the first paper to recognise this mode of failure. The authors strongly believe stems of this type should be used with caution in males with type A or AA bone.
We used dual-energy X-ray absorptiometry (DEXA) to measure the bone mineral content (BMC) of both tibiae in 13 patients who had been treated for a tibial fracture by rigid plate fixation. Within two weeks of plate removal the BMC was significantly greater in the bone that had been under the plate than at the same site in the control tibia. An unplated area of bone near the ankle showed a significant decrease in BMC at the time of plate removal with subsequent return to the level of the control tibia during the ensuing 18 months. We conclude that osteoinductive influences outweigh the potential causes of osteopenia, such as stress shielding and disuse, and that, contrary to expectation, demineralisation is not a factor in the diminished strength of the tibia after plating for fracture.
