Less risk of conversion to total knee arthroplasty without significant clinical and survivorship difference for opening-wedge high tibial osteotomies in varus knee deformities at 10-year minimum follow-up compared to closing-wedge high tibial osteotomies.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes and survivorship at minimum 10-year follow-up of patients undergoing primary valgisation high tibial osteotomy (HTO) for medial osteoarthritis (OA), treated by Opening-Wedge HTO (OW-HTO) or Closing-Wedge HTO (CW-HTO). METHODS: This was a retrospective cohort study of consecutive patients presenting to a single institution undergoing HTO for isolated medial compartment OA. Two hundred and twenty three HTOs for isolated medial tibio-femoral OA were performed between January 2002 and December 2010. Patients were eligible if they had minimum 10-year follow-up and received either a CW or OW-HTO. Fifteen (6.7%) patients died and twenty-five (11.2%) were lost to follow-up. One hundred and eighty three (82.1%) patients were included in the final analysis and divided into two groups: OW-HTO (96/183; 52.4%) and CW-HTO (87/183; 47.6%). Range of motion, KSS, KOOS scores, and conversion to TKA rate were analyzed between groups. Both groups were comparable regarding age, arthrosis stage, gender, ASA score and BMI at the time of HTO. Survival analysis was conducted with re-intervention for TKA as the end point. RESULTS: At the time of HTO, mean age was 55 years ± 7.9 (27-73.9) with 72.7% of patients being male. The mean follow-up was 13.3 years ± 2.7 (10-19). Sixty-four (34.9%) patients underwent TKA at a mean delay of 9.3 years ± 3 (3-16). The conversion to TKA rate was significantly higher in the CW-HTO group versus the OW-HTO group: 42.5% (37/87) versus 28.1% (27/96) (p = 0.04). The survival at 15-year follow-up was 59.2% in the OW-HTO group versus 54.6% in the CW-HTO group (n.s.). At 13-year follow-up, KSS Function score was significantly better in the OW-HTO (90.9 versus 82.4; p = 0.007). No significant difference was observed between the two groups regarding the KOOS score, KSS Knee Score and complication rate. CONCLUSION: At mean follow-up of 13 years, no significant clinical and survivorship difference was observed between the two groups. The conversion to TKA was significantly lower following OW-HTO. Minor correction was associated with risk of requiring subsequent TKA. LEVEL OF EVIDENCE: Retrospective case series, IV.

Kinematic alignment matches functional alignment for the extension gap: a consecutive analysis of 749 primary varus osteoarthritic knees with stress radiographs.

PURPOSE: The alignment goal in total knee arthroplasty (TKA) remains debated. Two major strategies have emerged based on recreating the native knee: kinematic and functional alignment (KA and FA). Recently a new Coronal Plane Alignment of the Knee (CPAK) classification for KA, based on bony landmarks, was described considering joint line obliquity and the arithmetic HipKneeAnkle angle (aHKA). Valgus corrected HKA medial angle (vcHKA) was measured on distractive valgus preoperative radiographs compensating for cartilage wear and ligament balance in varus osteoarthritis. The purpose of this study was to determine if aHKA accounts for differences in medial laxity for the extension gap by comparing vcHKA to aHKA. The hypothesis was that no significant difference would be observed between the two measurements. METHODS: This is a retrospective analysis of 749 knees in consecutive patients presenting to a single-centre with primary medial osteoarthritis. Patients underwent standardized weight bearing long-leg and valgus stress radiographs. Tibial mechanical angle (TMA), femoral mechanical angle (FMA) and vcHKA were measured using digital software. aHKA and vcHKA were compared to determine differences due to soft tissue balancing. RESULTS: The mean FMA was 91.3 ± 2.2° (range 82°-97°), the mean TMA was 85.7 ± 2.5° (range 75°-98°), the mean aHKA was 177.0 ± 3.0° (range 164°-185°) and the mean vcHKA was 176.6 ± 3.1° (range 165°-192°). No significant difference was observed between aHKA and vcHKA (p = 0.06). A significant correlation was found between vcHKA and TMA (ρ = 0.3; p < 0.001) and between vcHKA and FMA (ρ = 0.41; p < 0.001). CONCLUSION: This study showed that vcHKA was similar to aHKA confirming that aHKA accounts for ligamentous medial laxity. Therefore, kinematic alignment based on the CPAK classification matches the pre-arthritic coronal alignment of the knee for the extension gap. LEVEL OF EVIDENCE: IV.

Similar outcomes to primary total knee arthroplasty achievable for aseptic revision using the same primary posterior-stabilised prosthesis at a mean follow-up of 49 months.

PURPOSE: The aim of the study was to compare clinical and radiological outcomes between primary and aseptic revision TKAs using the same posterior-stabilised (PS) prosthesis. The authors hypothesised similar outcomes between both groups for selected patients. METHODS: This retrospective, case-control study assessed 36 patients who underwent aseptic revision TKA compared to a match group of 72 primary TKA. Both groups had the same PS design implant (ANATOMIC®, Amplitude, Valence, France). The International Knee Society (IKS) score, radiological outcomes (postoperative alignment, patellar tilt and radiolucent lines), re-intervention and revision rate were compared between the two groups with a minimum follow-up of 3 years. RESULTS: The final study cohort included 29 patients and 63 patients respectively in the revision and primary group, with a mean follow-up of 49.1 months (range 36.1-69). Postoperatively, there was no significant difference in IKS scores between the two groups [169.8 for the revision group and 179.6 for the primary group (p = 0.09)]. No statistical difference was observed for post-operative satisfaction 86.2% versus 92.1% (p = 0.46). Between the two groups, there was no difference in mean radiological assessment, including radiolucent lines (p = 0.7). There was no significant difference for overall implant survivorship 96.5% versus 100% (p = 0.13) at 36 months. CONCLUSION: Similar clinical, radiological and survivorship outcomes were found between rTKA and primary TKA groups using the same PS level of constraint in patients undergoing revision surgery for aseptic indications at 3-year follow-up. Use of PS implants in rTKA for the correct indication suggests this to be a safe approach at least in the medium term. LEVEL OF EVIDENCE: IV, retrospective case-control study.

Robotic-assisted total knee arthroplasty with the OMNIBot platform: a review of the principles of use and outcomes.

INTRODUCTION: Technology that enables the orthopaedic surgeon to deliver a surgical plan with precision and reproducibility continues to evolve. Robotic TKA represents the next phase of technological development in knee arthroplasty. Multiple propriety robotic platforms are now available for use in TKA, and one such system is the OMNIBotics platform. We conducted a review of this system, reporting its history and principles of use, published outcomes and our own personal experience performing OMNI robotic-assisted TKAs. MATERIALS AND METHODS: A literature review was conducted using the PRISMA guidelines. Thirteen papers were included for the final review. RESULTS: The OMNIBot is an accurate and consistent delivery tool in TKA surgery and compares favourably to instrumented, navigation-assisted and patient-specific cutting guides. The OMNIBot has been shown to be a reliable tool for delivering different alignment philosophies as well as planning and achieving tibio-femoral coronal balancing. The utility of the system is increased when the robot is used in conjunction with a soft-tissue tensioning device-the BalanceBot. Data regarding PROM's are limited, however results to date show reliable outcomes. Survival analysis of RATKA using the OMNIBot is limited to one study which reported 99.26% survivorship at 3 years. We report our own outcomes using the OMNIBot, having performed 766 TKA's using the OMNIBot, since 2014 with 99.48% survivorship at 6 year follow-up. CONCLUSION: The OMNIBot platform is an imageless, passive robotic system available since 2007, with over 30,000 TKA's being performed with its assistance. It has a small physical footprint, is relatively inexpensive and time efficient. Our review demonstrates a high level of precision of the surgical planning, with a modestly improved accuracy compared to conventional and navigation technology. Published outcomes are limited, however demonstrate good short-term PROM's and survivorship data that compare favourably to other robotic TKA cohorts.

Cannulated screw versus Kirschner-wire fixation for Milch II lateral condyle fractures in a paediatric sawbone model: a biomechanical comparison.

PURPOSE: Lateral condyle fractures of the humerus are common in the paediatric population, accounting for up to 20% of elbow fractures. Traditional management involves internal fixation with Kirschner (K)-wires, however, this has been associated with complications and insufficiently rigid fixation. Recently, cannulated screws have been proposed as a more stable method of fixation. While cannulated screws have been thought to allow earlier range of movement and shorten time to union, data regarding the biomechanical performance and optimal screw placement is scarce. We hypothesize that cannulated screw fixation is superior to K-wire fixation and screw placement can enhance the stability of the construct. METHODS: Paediatric humerus sawbones with Milch II fractures were fixed with one of three methods. Fractures were reduced with either a single cannulated screw either through the centre of the capitellum (oblique), or placed up the lateral column across the growth plate (lateral), or fixed with two K-wires. Fixed sawbone fractures were then mechanically tested in two directions simulating in vivo forces. RESULTS: The lateral screw construct had a higher maximum force to failure, higher stiffness and absorbed higher energy as compared with the K-wire fixation and oblique screw under an anterior force. When loaded from the posterior direction, only the lateral column screw was better than K-wire fixation. CONCLUSIONS: Screw fixation is a biomechanically effective alternative to K-wire fixation, especially when placed up the lateral column of the distal humerus. Further clinical studies are required before transcapitellar screw fixation can be adopted.

Clinical, functional and radiological outcomes of extracorporeal irradiation in limb salvage surgery for bone tumours.

AIMS: We present a retrospective review of patients treated with extracorporeally irradiated allografts for primary and secondary bone tumours with the mid- and long-term survivorship and the functional and radiographic outcomes. PATIENTS AND METHODS: A total of 113 of 116 (97.4%) patients who were treated with extracorporeally irradiated allografts between 1996 and 2014 were followed up. Forms of treatment included reconstructions, prostheses and composite reconstructions, both with and without vascularised grafts. Survivorship was determined by the Kaplan-Meier method. Clinical outcomes were assessed using the Musculoskeletal Tumor Society (MSTS) scoring system, the Toronto Extremity Salvage Score (TESS) and Quality of Life-C30 (QLQ-30) measures. Radiographic outcomes were assessed using the International Society of Limb Salvage (ISOLS) radiographic scoring system. RESULTS: There were 61 (54%) men with a mean age of 22 years (6 to 70) and 52 (46%) women with a mean age of 26 years (3 to 85). There were 23 deaths. The five-year patient survivorship was 82.3% and the ten-year patient survivorship was 79.6%. The mean follow-up of the 90 surviving patients was 80.3 months (2 to 207). At the last follow-up, 105 allografts (92.9%) were still in place or had been at the time of death; eight (7%) had failed due to infection, local recurrence or fracture. Outcome scores were comparable with or superior to those in previous studies. The mean outcome scores were: MSTS 79% (sd 8); TESS 83% (sd 19); QLQ 82% (sd 16); ISOLS 80.5% (sd 19). Pearson correlation analysis showed a strong relationship between the MSTS and ISOLS scores (r = 0.71, p < 0.001). CONCLUSION: This study shows that extracorporeal irradiation is a versatile reconstructive technique for dealing with large defects after the resection of bone tumours with good functional and radiographic outcomes. Functional outcomes as measured by MSTS, TESS and QLQ-30 were strongly correlated to radiographic outcomes. Cite this article: Bone Joint J 2017;99-B:1681-8.