Background

Multiple randomised controlled trials have demonstrated that arthroscopy provides little benefit in patients with knee osteoarthritis. In 2008, NICE released guidelines to reflect this evidence. Implementation has been sporadic, and arthroscopy for knee osteoarthritis is commonly performed with an annual incidence of 9.9 per 10,000 in England. Our aim was to establish whether previous arthroscopy affects Patient Reported Outcome Measures (PROMs) in Total Knee Replacement (TKR) patients.

This study was designed to identify the radiological changes of the knee that correlated with an unfavorable outcome when treated with an intra-articular knee viscoelastic supplementation. A prospective cohort of 60 patients receiving a standard course of intra-articular knee viscoelastic supplementation with a commercial uncrosslinked hyaluronic acid derivative of an intermediate molecular weight were studied.

Follow-up was for 12 weeks post treatment with clinical improvement measured using the Western Ontario and McMasters Universities Osteoarthritis Index. Radiographs of the relevant knee were viewed and graded for the severity of joint space, osteophyte, tibial spine, sclerosis, cyst formation, alignment and general severity by an observer blinded to the outcome of the treatment.

There were no appreciable differences noted in the age, sex, length of follow up, prior treatment, the severity of symptoms before treatment and number of intra-articular injections given per course in each radiographic category identified. There was a significant amount of improvement in patients with a minor loss of medial and lateral joint space in all outcome measures. Minimal changes in tibial spine and global appearance also indicated a positive outcome in stiffness, pain and overall improvement. Thus, patients with moderate to severe osteoarthritic changes in joint space on radiographic examination would not significantly benefit from intra-articular knee viscoelastic supplementation. In addition, we feel that changes in the tibial spine and global appearance are not reviewed consistently enough to be included as part of our recommendation. As such, we conclude that only patients with a minimal to mild loss in joint space on radiological examination should form part of the target group who are likely to benefit from intra-articular knee viscoelastic supplementation.

Introduction: Fusion of the knee joint should be the last option for salvage of infected total knee arthroplasty (TKA). Although knee arthrodesis implies lost of function, it is a successful treatment in eradicating the infection and in decreasing pain.

External fixation compression devices have been an excellent method for gaining fusion but, there is no documentation about its ability for obtaining adequate limb alignment with a stable fusion of the knee joint.

Material and Methods: We have retrospectively reviewed the results of knee arthrodesis after infection of TKA using an anteriorly placed unilateral external fixator. In addition, we have assessed patient self-satisfaction.

Postoperative radiographs have been evaluated to digitally measure loss of femoral and tibial bone stock using Engh radiological classification. Moreover, we have quantified tibiofemoral alignment and the section of bony fusion. Fusion of the knee joint was assessed with CT. Patients were interviewed and pain was graded using a Visual Analog Scale (VAS) and self-satisfaction as well as current health status using the 12-item social function survey form (SF12).

Results: From 1992 to 2003, 52 arthrodeses were done for treatment of infected TKA. The average age was 71 years (range, 37–83 years). Type III bone defect according with Engh classification, in femur and/or in tibia, was present in 50% of the patients. The average postoperative tibiofemoral alignment was 1.2° (SD 3.79). The mean time to fusion was 11.26 months (range, 3–30 months). Time to fusion was statistical related with severe bone loss and with the tibiofemoral contact section. The average score according VAS was 1.6 (SD 2.60).

Conclusions: Knee arthrodesis using a monolateral external fixator for infected TKA is an effective method to control infection as well as to obtain knee fusion and pain relief. Severe bone loss, frequently present in infected TKA, was found to be the most relevant factor in achieving tibiofemoral union. The individual clinical result according to SF12 shows a lower quality of life both for physical and mental components compare with general population.

Several emerging reports suggest an important involvement of the hindfoot alignment in the outcome of knee osteotomy. At present, studies lack a comprehensive overview. Therefore, we aimed to systematically review all biomechanical and clinical studies investigating the role of the hindfoot alignment in the setting of osteotomies around the knee. A systematic literature search was conducted on multiple databases combining “knee osteotomy” and “hindfoot/ankle alignment” search terms. Articles were screened and included according to the PRISMA guidelines. A quality assessment was conducted using the Quality Appraisal for Cadaveric Studies (QUACS) - and modified methodologic index for non-randomized studies (MINORS) scales. Three cadaveric, fourteen retrospective cohort and two case-control studies were eligible for review. Biomechanical hindfoot characteristics were positively affected (n=4), except in rigid subtalar joint (n=1) or talar tilt (n=1) deformity. Patient symptoms and/or radiographic alignment at the level of the hindfoot did also improve after knee osteotomy (n=13), except in case of a small pre-operative lateral distal tibia- and hip knee ankle (HKA) angulation or in case of a large HKA correction (>14.5°). Additionally, a pre-existent hindfoot deformity (>15.9°) was associated with undercorrection of lower limb alignment following knee osteotomy. The mean QUACS score was 61.3% (range: 46–69%) and mean MINORS score was 9.2 out of 16 (range 6–12) for non-comparative and 16.5 out of 24 (range 15–18) for comparative studies. Osteotomies performed to correct knee deformity have also an impact on biomechanical and clinical outcomes of the hindfoot. In general, these are reported to be beneficial, but several parameters were identified that are associated with newly onset – or deterioration of hindfoot symptoms following knee osteotomy. Further prospective studies are warranted to assess how diagnostic and therapeutic algorithms based on the identified criteria could be implemented to optimize the overall outcome of knee osteotomy. Remark: Aline Van Oevelen and Arne Burssens contributed equally to this work

Increasing expectations from arthroscopic anterior cruciate ligament (ACL) reconstructions require precise knowledge of technical details such as minimum intra-femoral tunnel graft lengths. A common belief of having ≥20mm of grafts within the femoral tunnel is backed mostly by hearsay rather than scientific proof. We examined clinico-radiological outcomes in patients with intra-femoral tunnel graft lengths <20 and ≥20mm. Primary outcomes were knee scores at 1-year. Secondarily, graft revascularization was compared using magnetic resonance imaging (MRI). We hypothesized that outcomes would be independent of intra-femoral tunnel graft lengths. This prospective, single-surgeon, cohort study was conducted at a tertiary care teaching centre between 2015–2018 after obtaining ethical clearances and consents. Eligible arthroscopic ACL reconstruction patients were sequentially divided into 2 groups based on the intra-femoral tunnel graft lengths (A: < 20 mm, n = 27; and B: ≥ 20 mm, n = 25). Exclusions were made for those > 45 years of age, with chondral and/or multi-ligamentous injuries and with systemic pathologies. All patients were postoperatively examined and scored (Lysholm and modified Cincinnati scores) at 3, 6 and 12 months. Graft vascularity was assessed by signal-to-noise quotient ratio (SNQR) using MRI. Statistical significance was set at p<0.05. Age and sex-matched patients of both groups were followed to 1 year (1 dropout in each). Mean femoral and tibial tunnel diameters (P =0.225 and 0.595) were comparable. Groups A (<20mm) and B (≥20mm) had 27 and 25 patients respectively. At 3 months, 2 group A patients and 1 group B patient had grade 1 Lachman (increased at 12 months to 4 and 3 patients respectively). Pivot shift was negative in all patients. Lysholm scores at 3 and 6 months were comparable (P3= 0.195 and P6= 0.133). At 1 year both groups showed comparable Cincinnati scores. Mean ROM was satisfactory (≥130 degrees) in all but 2 patients of each group (125–130 degrees). MRI scans at 3 months and 1 year observed anatomical tunnels in all without any complications. Femoral tunnel signals in both groups showed a fall from 3–12 months indicating onset of maturation of graft at femoral tunnel. Our hypothesis, clinical and radiological outcomes would be independent of intra-tunnel graft lengths on the femoral aspect, did therefore prove correct. Intra-femoral tunnel graft lengths of <20 mm did not compromise early clinical and functional outcomes of ACL reconstructions. There seems to be no minimum length of graft within the tunnel below which suboptimal results should be expected

Increased collection of patient-reported outcome measures (PROM) in registries enables international comparison of patient-centered outcomes after knee and hip replacement. We aimed to investigate 1) variations in PROM improvement, 2) the possible confounding factor of BMI, and 3) differences in comorbidity distributions between registries. Registries affiliated with the International Society of Arthroplasty Registries (ISAR) or OECD membership countries were invited to report aggregate EQ-5D, OKS, OHS, HOOS-PS and KOOS-PS values. Eligible patients underwent primary total, unilateral knee or hip replacement for osteoarthritis within three years and had completed PROMs preoperatively and either 6 or 12 months postoperatively, excluding patients with subsequent revisions. For each PROM cohort, Chi-square tests were performed for BMI distributions across registries and 12 predefined PROM strata (male/female, age 20-64/65-74/>75, high or low preoperative PROM scores). Comorbidity distributions were reported for available comorbidity indexes. Thirteen registries from 9 countries contributed data, n~130000 knee (range 140 to 79848) and n~113000 hip (range 137 to 85281). Mean EQ-5D index values (10 registries) ranged from 0.53 to 0.71 (knee) and 0.50 to 0.70 (hips) preoperatively and 0.78 to 0.85 (knee) and 0.83 to 0.87 (hip) postoperatively. Mean OKS (6 registries) ranged from 19.3 to 23.6 preoperatively and 36.2 to 41.2 postoperatively. Mean OHS (7 registries) ranged from 18.0 to 23.2 preoperatively and 39.8 to 44.2 postoperatively. Four registries reported KOOS-PS and three reported HOOS-PS. Proportions of patients with BMI >30 ranged from 35 to 62% (10 knee registries) and 16 to 43% (11 hip registries). For both knee and hip registries, distributions of patients across six BMI categories differed significantly among registries (p30 were for patients in the youngest age groups (20 to 64 and 65 to 74 years) with the lowest baseline scores. Additionally, females with lowest preoperative PROM scores had highest BMI. These findings were echoed for the OHS and OKS cohorts. Proportions of patients with ASA scores ≥3 ranged from 7 to 42% (9 knee registries) and 6 to 35% (8 hip registries). PROM-score improvement varies between international registries, which may be partially explained by differences in age, sex and preoperative scores. BMI and comorbidity may be relevant to adjust for

Abstract. Introduction. Knee arthrodesis is one of the treatment options for limb salvage of a failed total knee replacement (TKR) when further revisions were contraindicated. The aim of this study is to determine patient outcomes after knee arthrodesis (KA) following a failed TKR. Methodology. A literature search was conducted for studies published from January 2000 through January 2022 via Medline, Web of Science, Embase and Cochrane databases. Only primary research studies were included with independent extraction of articles by two reviewers. Results were synthesised by narrative review according to PRISMA guidelines, with full tabulation of all included study results. Results. A total of 34 studies with 1,034 patients were included in the review; all were longitudinal observational studies, and none were conducted as randomised controlled trials. Reporting methods were very inconsistent in the included studies, and this heterogeneity led to pooled data totals that varied widely in different categories. The mean follow-up was 3.5 years. Overall, 72.0% (167 of 232) of patients used a walking stick and 12.5% (36 of 287) remained non-ambulatory after KA. Only 7.7% (58 of 752) of patients subsequently underwent above-knee amputation. Conclusion. KA is a potential limb salvage procedure after revision arthroplasties have been attempted in cases of failed TKR. Most patients were able to ambulate both at home and in the community, although with an increased rate of using a walking stick after the operation. However, in the absence of randomised controlled trials, these data may allow for a more accurate counselling and decision making

Abstract. Introduction. COMPOSE describes the demographics, fracture characteristics, management and associated outcomes of knee femoral periprosthetic fractures (KFPPF). Methods. Multicentre retrospective cohort study conducted 01/01/2018-31/12/2018. Data collected included: patient demographics, social and mobility characteristics, fracture characteristics, management strategy and post-treatment outcomes (length of stay, reoperation, readmission, 30-day and 12-month mortality). Results. 785 PPFs from 27 NHS sites were included in the COMPOSE cohort. Of these 162 (21%) were related to an isolated knee prosthesis (151 femur, 10 tibia and 1 patella). The KFPPF group had a mean age of 81.1 years, 127 (84%) female, 114 (76%) living in their own home, with 99 (63%) reliant on walking aids/bedbound. Most fractures were B (58%) or C (35%) type and occurred around a primary cemented replacement (141,94%) at a mean of 8.2 years after surgery. 116 (76.8%) KFPPFs were treated operatively. Mean time to surgery was 5 days and the commonest surgical strategy was fixation alone (64%) vs revision+/-fixation (36%). Mean operative time was 126 minutes and 11 (10%) patients required ITU/HDU admission after surgery. Mean LOS was 22 days and 47 patients (31%) experienced a complication prior to discharge. Overall, 5 patients (3%) had a further operation within 12 months, 7 (5%) were readmitted within 30 days and the 30-day and 12-month mortality were 6.6% and 23.2% respectively. Conclusions. KFPPF patients are elderly and frail and have mortality, re-operation and readmission rates comparable to hip fracture patients. However, they wait longer for surgery and surgical treatment is more complex

Aims. Postoperative malalignment of the femur is one of the main complications in distal femur fractures. Few papers have investigated the impact of intraoperative malalignment on postoperative function and bone healing outcomes. The aim of this study was to investigate how intraoperative fracture malalignment affects postoperative bone healing and functional outcomes. Methods. In total, 140 patients were retrospectively identified from data obtained from a database of hospitals participating in a trauma research group. We divided them into two groups according to coronal plane malalignment of more than 5°: 108 had satisfactory fracture alignment (< 5°, group S), and 32 had unsatisfactory alignment (> 5°, group U). Patient characteristics and injury-related factors were recorded. We compared the rates of nonunion, implant failure, and reoperation as healing outcomes and Knee Society Score (KSS) at three, six, and 12 months as functional outcomes. We also performed a sub-analysis to assess the effect of fracture malalignment by plates and nails on postoperative outcomes. Results. The rates of nonunion and reoperation in group U were worse than those in group S (25.0% vs 14.3%; 15.6% vs 5.6%), but the differences were not significant (p = 0.180 and p = 0.126, respectively). Mean KSS in group U at all follow-up periods was significantly worse that in group S (75.7 (SD 18.8) vs 86.0 (SD 8.7); p < 0.001; 78.9 (SD 17.2) vs 89.1 (SD 9.8); p < 0.001; 85.0 (SD 11.9) vs 91.1 (SD 7.2); p = 0.002, respectively). In the sub-analysis of plates, mean KSS was significantly worse in group U at three and six months. In the sub-analysis of nails, the rate of reoperation was significantly higher in group U (28.6% vs 5.8%; p = 0.025), and mean KSS at six and 12 months was significantly worse in Group U. Conclusion. To obtain good postoperative functional results, intraoperative alignment of the coronal plane should be accurately restored to less than 5°. Cite this article: Bone Jt Open 2022;3(2):165–172

Aims

The Coronal Plane Alignment of the Knee (CPAK) classification has been developed to predict individual variations in inherent knee alignment. The impact of preoperative and postoperative CPAK classification phenotype on the postoperative clinical outcomes of total knee arthroplasty (TKA) remains elusive. This study aimed to examine the effect of postoperative CPAK classification phenotypes (I to IX), and their pre- to postoperative changes on patient-reported outcome measures (PROMs).

Aims

Orthopaedic surgery requires grafts with sufficient mechanical strength. For this purpose, decellularized tissue is an available option that lacks the complications of autologous tissue. However, it is not widely used in orthopaedic surgeries. This study investigated clinical trials of the use of decellularized tissue grafts in orthopaedic surgery.

Patient-reported outcome measures (PROMs) are being used increasingly in total knee arthroplasty (TKA). We conducted a systematic review aimed at identifying psychometrically sound PROMs by appraising their measurement properties. Studies concerning the development and/or evaluation of the measurement properties of PROMs used in a TKA population were systematically retrieved via PubMed, Web of Science, Embase, and Scopus. Ratings for methodological quality and measurement properties were conducted according to updated COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology. Of the 155 articles on 34 instruments included, nine PROMs met the minimum requirements for psychometric validation and can be recommended to use as measures of TKA outcome: Oxford Knee Score (OKS); OKS–Activity and Participation Questionnaire (OKS-APQ); 12-item short form Knee Injury and Osteoarthritis Outcome (KOOS-12); KOOS Physical function Short form (KOOS-PS); Western Ontario and McMaster Universities Arthritis Index-Total Knee Replacement function short form (WOMAC-TKR); Lower Extremity Functional Scale (LEFS); Forgotten Joint Score (FJS); Patient’s Knee Implant Performance (PKIP); and University of California Los Angeles (UCLA) activity score. The pain and function subscales in WOMAC, as well as the pain, function, and quality of life subscales in KOOS, were validated psychometrically as standalone subscales instead of as whole instruments. However, none of the included PROMs have been validated for all measurement properties. Thus, further studies are still warranted to evaluate those PROMs. Use of the other 25 scales and subscales should be tempered until further studies validate their measurement properties. Cite this article: Bone Joint Res 2021;10(3):203–217

In total knee arthroplasty (TKA), both intravenous (IV) and/or intra-articular (IA) administration of tranexamic acid (TXA) were showed to reduce blood loss. Moreover, research suggesting TXA decreases postoperative knee swelling, but it is unknown whether this results in improved postoperative rehabilitation outcome. Thus, the aim of this study was to evaluate whether combined IV and IA administration of TXA would associate with improved early rehabilitation outcomes. In this institutional review board approved randomized controlled trial, 179 patients scheduled for unilateral TKA were randomized to one of three regimens: (1) IA administration of 1gm TXA at end of procedure only, (2) additional preoperative IV dose of 15 mg/kg 30min before tourniquet inflation, and (3) additional postoperative dose 4hrs after preoperative dose. Primary outcomes included knee range of motion, Knee Society Score (KSS) at 6-month postoperatively, haemoglobin drop at day-2 post-operatively, and transfusion rate. Secondary outcome was venous thromboembolism (VTE) complications. Baseline characteristics were comparable between the allocation groups. Patients in regimen (3) showed statistically significant better knee extension range (6.2°, 5.9°, 2.9°, p=0.01), and KSS (88.5, 89.9, 93.0, p=0.02) at 6-month postoperatively, and lesser drop in haemoglobin at day-2 post-operatively (2.72, 2.47, 1.75 g/dL, p=0) when compared with patients in other regimens. No patients required transfusion, or complicated by VTE. The combined administration of IA and IV TXA, including both preoperative and postoperative doses, associated with statistically significantly improved early rehabilitation outcomes. The improvement may be related to higher haemoglobin level and decreased knee swelling in patients having regimen (3). For any reader queries, please contact . cpk464@yahoo.com.hk

Aims

Single-shot adductor canal block (ACB) after total knee arthroplasty (TKA) for postoperative analgesia is a common modality. Patients can experience breakthrough pain when the effect of ACB wears off. Local anaesthetic infusion through an intra-articular catheter (IAC) can help manage breakthrough pain after TKA. We hypothesized that combined ACB with ropivacaine infusion through IAC is associated with better pain relief compared to ACB used alone.

Aims

Nearly 99,000 total knee arthroplasties (TKAs) are performed in UK annually. Despite plenty of research, the satisfaction rate of this surgery is around 80%. One of the important intraoperative factors affecting the outcome is alignment. The relationship between joint obliquity and functional outcomes is not well understood. Therefore, a study is required to investigate and compare the effects of two types of alignment (mechanical and kinematic) on functional outcomes and range of motion.

Introduction. The success of total knee arthroplasty (TKA) necessitates precise osteotomies and soft tissue balancing to realign the lower extremity to a neutral mechanical axis. While technological advances have facilitated precise osteotomies, soft tissue balancing has traditionally relied mostly on surgeons’ subjective and variable tactile feedback. As soft tissue imbalance accounts for 35% of early TKA revisions in North America, we aimed to compare outcomes when TKA was balanced free-hand versus a sensor-guided balancing device (VERASENSE, OrthoSensor, Inc (Dania, FL)). Methods. In a randomized-controlled fashion, patients underwent primary TKA soft tissue balancing either free-hand or with VERASENSE (Orthosensor Inc, Dania FL) at our institution beginning January 2018. With VERASENSE, soft-tissue balancing is considered when the pressure difference between the medial and lateral knee compartments was less than 15 pounds. Data regarding patient-reported outcomes, knee range of motion (ROM), pain level, opioid consumption, inpatient ambulation distance, length of stay (LOS), and incidence of arthrofibrosis was collected and analyzed in a two-year minimum follow-up and target patient goal of 120 patients. Results. The study cohort thus far consists of 53 patients, average age 72.4 ± 8.8 years. Soft-tissue balance was conducted freehand in 23 patients and the VERASENSE was used in 30 patients. In the free-hand cohort, preoperative patient-reported outcomes for SF-12 Physical, Mental, WOMAC (pain, stiffness, function) parameters, and knee society function score (KSFS) were 39.3, 45.8, 47.7, 37.5, 48.1, and 50.0, respectively and post-operative at 3 months were 45.0, 53.0, 79.5, 72.5, 81.0, and 72.5, respectively; difference between preoperative and post-operative ROM was +8.4 degrees; average VAS pain score in the first 3 post-operative days was 2.9 ± 2.3; average opioid consumption was 100.7 ± 103.3 mg morphine equivalents; average inpatient ambulation per day was 267.9 ± 187.4 feet; average LOS was 2.3 days. In the VERASENSE cohort, patient reported outcomes for SF-12 Physical, Mental, WOMAC (pain, stiffness, function) parameters, and knee society function score (KSFS) were 38.2, 48.6, 40.1, 30.3, 40.0, and 48.7, respectively and post-operative at 3 months were 41.9, 47.6, 67.2, 59.7, 69.1, and 56.7; difference between preoperative and post-operative ROM was +3.9 degrees; average VAS pain score in the first 3 post-operative days was 2.9 ± 2.3; average opioid consumption was 105.8 ± 86.7 mg morphine equivalents; average inpatient ambulation was 384.6 ± 316.1 feet; average LOS was 2.1 days. There was no incidence of arthrofibrosis and subsequent manipulation under anesthesia in the trial. Conclusion. Short-term follow up of this randomized-controlled trial demonstrates equivalent patient-reported and clinical outcomes when soft-tissue balancing in TKA is performed free-hand versus utilization of VERASENSE, though we hypothesize a difference in the long-term

Aims

The aim of this meta-analysis is to assess the association between exchange of modular parts in debridement, antibiotics, and implant retention (DAIR) procedure and outcomes for hip and knee periprosthetic joint infection (PJI).

Fifteen-year survivorships studies demonstrate that total knee replacements have excellent survivorship, with reports of 85 to 97%. However, excellent survivorship does not equate to excellent patient reported outcomes. Total knee imbalance with either too tight or loose soft tissues account for up to 54% of revisions in one series. This may account for many of the 20% unsatisfactory total knee arthroplasty outcomes. Soft tissue balancing technique is more like an art. The surgeon relies on subjective feel for appropriate ligamentous tension. Surgical experience and case volume play a major role in each surgeon's relative skill in balancing the knee properly. New technology of “smart trials” with embedded microelectronics and accelerometers, used in the knee with the medial retinaculum closed, can provide dynamic, intraoperative feedback regarding knee quantitative compartment pressures and component tracking. After all bone cuts are made using the surgeon's preferred techniques, trial components with the sensor tibial trial are inserted and the knee is taken through a passive range of motion. After visualizing the resultant compartment pressures and tracking data on a graphical interface, imbalance situations such as a too tight MCL or ITB, an incompetent or too tight PCL, or malrotated femoral or tibial component can be identified. A decision can be made as to whether to recut the bone to realign components, do a soft tissue release, or a combination of both. Soft tissue releases can be titrated while observing equalizing compartment pressures. Sensor feedback improves soft tissue balancing. More balanced compartments occur using a sensor trial than with standard soft tissue balancing technique blinded to sensor information. A multicenter three year study has shown that having the medial and lateral compartments in flexion and extension balanced within 15 pounds provides better outcomes. Patients with quantitatively balanced TKA with <15lbf mediolateral load differential have better forgotten knee scores at six weeks and six months. Use of smart trials is a new approach to total knee replacement surgery allowing fine tune balancing and takes soft tissue balancing from art to science

Introduction. Early complication post total knee replacement reported to be higher in obese patient in general. Also the outcome of cruciate retaining and PS knee has been fully discussed before and there was no major difference in the outcomes for all the patients overall regardless of their weight. However, the purpose of this paper is to find out if the CR knee has superiority over PS knee in terms of clinical and functional outcomes and if early complication postTKR such as fracture and instability is more common in PS implant than in CR knee. This is a retrospective study comparing two groups of obese patients. The first using PS implant and the other using CR implant. These two groups were matched for age, body mass and severity of deformity. Materials & Methods. At our institution we have been using Persona implant which has the option of using PS insert or a CR. The decision to proceed with CR or PS mainly depends on the availability of the implant and also the ability to well balance the knee in patients. In most patients we try to proceed with CR implant. However, the flow of implant sometime sometimes limit us from using CR or the imbalance in the ligament force us to process with PS implant. We have reviewed a chart of over 200 patients in each group of obese patient they were done within the last three years. All cases had a minimum follow up of 6 months. Those groups were matched for body mass, age and severity of deformity. After matching the groups we documented Knee Society Score (KSS), Knee Society Function Score (KSFS), blood loss, post – operative pain and complications. All surgeries were performed by the same surgeon. Results. Our study showed that the clinical scores (KSS) in both groups were very close while significant differences were observed in functional scores (KSFS) for the CR knee. We had 8 cases of per-prosthetic fracture in the PS group and one in the CR implant. We had 4 revisions in the PS group for instability and MCL insufficiency and non in the CR implant. Infection, wound complication, blood loss, and patient satisfaction were same in both groups. Discussion. This study suggests a significant difference in functional outcomes, especially walking, stair climbing and the use of walking aids, between CR and PS that favors CR implant which may be related to the CR knee retaining proprioception and ligaments tension with balance. In addition, PS knee have more varus-valgus and mid-flexion laxity than CR knee throughout the range of motion which appear clearly in obese patient. On the other hand, the study clearly shows that the decrease incidence of peri-prosthetic fracture in the CR implant which could be easily explained by the fact that a good cortical bone is resected in order to make room for the PS spine. Also, the fact that resecting the posterior cruciate ligament might cause more stress on the implant versus the CR. Instability also were more common in the PS group. We believe this has to do with the fact that the PCL serve as a secondary constraint to the MCL. The presence of the PCL help maintain the stability in case of incidental injury to the MCL during surgery which was reported to be higher in obese patients. Conclusion. There is clear advantage of improving the outcomes or knee scores and decreasing the early postoperative complications in obese patient using CR knee and we strongly recommend using CR implant in obese patients in order to restore functionality faster and reduce the incidence of peri-prosthetic fracture and the revision for instability

The purpose of the following study was to present the general strategy for preserving the lower extremity by knee arthrodesis and to analyze the outcome of knee arthrodeses performed by a special modular system. Between 2009 and 2014 35 knee arthrodeses were performed. 23 patients were male, 12 female. The average age was 66 years (42 to 83 years). The patients underwent an average of 6 operations because of infected knee arthroplasties previous to the knee arthrodesis. The main pathogen was S. epidermidis followed by MRSA. The arthrodeses system included a non cemented femoral and tibial stem (press fit application plus two static locking screws). These were connected by a special stem to stem clamp. Immediate postoperative full weight-bearing was possible in 32 of 35 patients. We saw 4 recurrent infections (all connected to the patients, who did not show a full weight bearing after knee arthrodesis). In two cases re-revision surgery was successful and lead to a sufficient re-arthrodesis. In two cases above-knee-amputation was necessary. Peri-implant fractures were detected in 3 cases. All of them could be cured by changing the arthrodesis stem and to a longer one bridging the fracture. In one case a stem loosening was seen. This was as well addressed by the use of a longer stem. Knee arthrodesis by a modular non cemented system is a god alternative in order to preserve the weight-bearing lower extremity. The complication rate is rather high due to the fact, that this procedure presents the final alternative to do so in patients, who are in extremis in terms of a long lasting aggressive peri-arthroplasty infection the lead to massive destruction of the soft tissue around the knee and a significant loss of function