Predicting Delayed In-Hospital Recovery of Physical Function After Total Knee Arthroplasty.

Objective: To identify patients at high risk of delayed in-hospital functional recovery after knee replacement surgery by developing and validating a prediction model, including a combination of preoperative physical fitness parameters and patient characteristics. Design: Retrospective cohort study using binary logistic regression. Setting: University hospital, orthopedic department. Participants: 260 adults (N=260) (≥18y) with knee osteoarthritis awaiting primary unilateral total knee arthroplasty and assessed during usual care between 2016 and 2020. Intervention: Not applicable. Main Outcome Measures: Time to reach in-hospital functional independence (in days), measured by the modified Iowa Level of Assistance Scale. A score of 0 means completely independent. Potential predictor variables are a combination of preoperative physical fitness parameters and patient characteristics. Results: Binary logistic regression modeling was applied to develop the initial model. A low de Morton Mobility Index (DEMMI), walking aid use indoors, and a low handgrip strength (HGS) were the most important predictors of delayed in-hospital recovery. This model was internally validated and had an optimism-corrected R2 of 0.07 and an area under curve of 61.2%. The probability of a high risk of delayed in-hospital recovery is expressed by the following equation:Phighrisk=(1/(1+e(-(2.638-0.193×DEMMI+0.879×indoorwalkingaid-0.007×HGS))))×100%. Conclusions: The model has a low predictive value and a poor discriminative ability. However, there is a positive association between preoperative physical fitness and postoperative recovery of physical function. The validity of our model to distinguish between high and low risk, based on preoperative fitness values and patient characteristics, is limited.

SnoRNA signatures in cartilage ageing and osteoarthritis.

Osteoarthritis presents as a change in the chondrocyte phenotype and an imbalance between anabolic and catabolic processes. Age affects its onset and progression. Small nucleolar RNAs (SnoRNAs) direct chemical modification of RNA substrates to fine-tune spliceosomal and rRNA function, accommodating changing requirements for splicing and protein synthesis during health and disease. Articular cartilage from young, old and OA knees was used in a microarray study to identify alterations in snoRNA expression. Changes in snoRNAs in osteoarthritis-like conditions were studied in chondrocytes using interleukin-1 and osteoarthritic synovial fluid. SNORD26 and SNORD96A knockdown and overexpression were undertaken using antisense oligonucleotides and overexpression plasmids. We identified panels of snoRNAs differentially expressed due to ageing (including SNORD96A, SNORD44) and osteoarthritis (including SNORD26 and SNORD116). In vitro experiments using osteoarthritis-like conditions affected snoRNA expression. Knockdown or overexpression of SNORD26 or SNORD96A resulted in changes in chondrogenic, hypertrophic, rRNA and osteoarthritis related gene expression. We demonstrate that snoRNA expression changes in cartilage ageing, and osteoarthritis and in osteoarthritis-like conditions, and when the expression of these snoRNAs is altered this affects chondrogenic and hypertrophic gene expression. Thus, we propose an additional dimension in the molecular mechanisms underlying cartilage ageing and osteoarthritis through the dysregulation of snoRNAs.

Enhanced recovery in usual health care improves functional recovery after total knee arthroplasty.

BACKGROUND: The success of total knee arthroplasty (TKA) is determined by an effective surgical procedure as well as a well-organized clinical care pathway. Research has shown that day-of-surgery mobilization decreases length of stay (LOS) and complication rates. We developed, implemented, and evaluated a new clinical care pathway for patients undergoing TKA, that included early mobilization, using 'Lean Six Sigma (LSS)', with the aim of accelerating functional recovery and reducing LOS. METHODS: Data derived from physical therapy reports and LOS were compared between the old (n = 85) and the new (n = 85) clinical care pathways for time to functional recovery (using the modified Iowa Level of Assistance Scale), LOS and joint-related readmission. Group differences were evaluated using Mann-Whitney and Chi-Square tests. The clinical care pathway was redesigned using LSS-methods. RESULTS: After implementation of the new pathway, median time to functional recovery improved from 4 (2-5) to 2 days (1-8)(P < 0.001) and LOS from 7 (5-11) to 4 days (3-12)(P < 0.001), joint-related readmission declined (3.5-2.4%)(P = 0.65). CONCLUSION: Implementation of the new clinical care pathway accelerated functional recovery and reduced LOS for patients undergoing TKA. Future research should focus on having multiple discharge moments per day which might encourage patients to achieve functional recovery as soon as possible.

Accuracy of the Precision Saw versus the Sagittal Saw during total knee arthroplasty: A randomised clinical trial.

BACKGROUND: The aim of this study was to compare the accuracy of the oscillating tip saw system (Precision Saw=PS) with the more conventional fully oscillating blade system (Sagittal Saw=SS) during computer-assisted total knee arthroplasty (CAS-TKA). METHODS: A prospective, randomised, controlled trial included 58 consecutive patients who underwent primary CAS-TKA and were randomly assigned in the PS group or the SS group to compare the accuracy of both blades. The primary outcome was the difference between the intended cutting planes and the actual cutting planes in degrees (°) in two planes of both the femur and the tibia. The secondary outcome was total surgery time. RESULTS: Tibia: In the VV-plane no significant differences were registered for the mean absolute deviation (p=0.28). The PS was more accurate in the AP-plane (p=0.03). Femur: The PS showed significantly fewer mean absolute deviations in the VV-plane (p=0.03); however, the SS revealed better accuracy in the FE-plane (p=0.04). The difference in the surgery time between the groups was not statistically significant (p=0.45). Two outliers were measured using the SS, while seven outliers were detected using the PS. CONCLUSION: The Precision Saw is not proven to be overall more accurate than the Sagittal Saw. Significantly better accuracy was shown with the PS in the two cutting planes, with the exception of one cutting plane that favoured the SS. Greater number of outliers were found using the PS. LEVEL OF EVIDENCE: II.

Measurement of lower limb alignment: there are within-person differences between weight-bearing and non-weight-bearing measurement modalities.

PURPOSE: Previous studies have compared weight-bearing mechanical leg axis (MLA) measurements to non-weight-bearing measurement modalities. Most of these studies compared mean or median values and did not analyse within-person differences between measurements. This study evaluates the within-person agreement of MLA measurements between weight-bearing full-length radiographs (FLR) and non-weight-bearing measurement modalities (computer-assisted surgery (CAS) navigation or MRI). MATERIALS AND METHODS: Two independent observers measured the MLA on pre- and postoperative weight-bearing FLR in 168 patients. These measurements were compared to non-weight-bearing measurements obtained by CAS navigation or MRI. Absolute differences in individual subjects were calculated to determine the agreement between measurement modalities. Linear regression was used to evaluate the possibility that other independent variables impact the differences in measurements. RESULTS: A difference was found in preoperative measurements between FLR and CAS navigation (mean of 2.5° with limit of agreement (1.96 SD) of 6.4°), as well as between FLR and MRI measurements (mean of 2.4° with limit of agreement (1.96 SD) of 6.9°). Postoperatively, the mean difference between MLA measured on FLR compared to CAS navigation was 1.5° (limit of agreement (1.96 SD) of 4.6°). Linear regression analysis showed that weight-bearing MLA measurements vary significantly from non-weight-bearing MLA measurements. Differences were more severe in patients with mediolateral instability (p = 0.010), age (p = 0.049) and ≥3° varus or valgus alignment (p = 0.008). CONCLUSION: The clinical importance of this study lies in the finding that there are within-person differences between weight-bearing and non-weight-bearing measurement modalities. This has implications for preoperative planning, performing total knee arthroplasty (TKA), and clinical follow-up after TKA surgery using CAS navigation or patient-specific instrumentation. LEVEL OF EVIDENCE: III.

Hereditary bilateral genu recurvatum: Case report of a family.

BACKGROUND: Genu recurvatum is a rare condition in children and adolescents. The origin can be osseous, ligamentous and mixed. METHODS: We describe for the first time a family inclusive two brothers and their mother with hereditary bilateral genu recurvatum of unknown etiology. The possible underlying pathology and treatment are discussed. RESULTS: The underlying pathology of the early closure of the apophysis of the tibial tuberosity remained unclear. The mother was never treated, one of the brothers received a tibial osteotomy as a young adult. Both patients developed end-stage osteoarthritis of both knees which was successfully treated by a bilateral computer-navigated TKA. At seven to eight years after implantation in the older brother (left and right knee, respectively) and three to four years after implantation in the younger brother (right and left knee, respectively), the Visual Analogue Scale (VAS) pain score on a 0 to 100 scale was 0 of both brothers, the EQ-5D health status was 80 (scale of 0 to 100), the satisfaction was 10 (scale of 10) of both brothers. The Knee Injury and Osteoarthritis Outcome Score (KOOS) function of the younger brother of 75 (scale 0 to 100) and of the older brother 100. The KOOS sport of the younger brother was 10 (scale 0 to 100), whereas that of the older brother 85. CONCLUSIONS: Hereditary bilateral genu recurvatum with end-stage osteoarthritis can be successfully treated with computer-navigated TKAs; however, impingement of the patella on the proximal tibia and the position of the tibial keel are of concern.

Noise Exposure in TKA Surgery; Oscillating Tip Saw Systems vs Oscillating Blade Saw Systems.

BACKGROUND: Historically it has been suggested that noise-induced hearing loss (NIHL) affects approximately 50% of the orthopedic surgery personnel. This noise may be partially caused by the use of powered saw systems that are used to make the bone cuts. The first goal was to quantify and compare the noise emission of these different saw systems during total knee arthroplasty (TKA) surgery. A second goal was to estimate the occupational NIHL risk for the orthopedic surgery personnel in TKA surgery by quantifying the total daily noise emission spectrum during TKA surgery and to compare this to the Dutch Occupational Health Organization guidelines. METHODS: A conventional sagittal oscillating blade system with a full oscillating blade and 2 newer oscillating tip saw systems (handpiece and blade) were compared. Noise level measurements during TKA surgery were performed during cutting and hammering, additionally surgery noise profiles were made. RESULTS: The noise level was significantly lower for the oscillating tip saw systems compared to the conventional saw system, but all were in a range that can cause NIHL. The conventional system handpiece produced a considerable higher noise level compared to oscillating tip handpiece. CONCLUSION: NIHL is an underestimated problem in the orthopedic surgery. Solutions for decreasing the risk of hearing loss should be considered. The use of oscillating tip saw systems have a reduced noise emission in comparison with the conventional saw system. The use of these newer systems might be a first step in decreasing hearing loss among the orthopedic surgery personnel.

Tibial component rotation in total knee arthroplasty.

BACKGROUND: Both the range of motion (ROM) technique and the tibial tubercle landmark (TTL) technique are frequently used to align the tibial component into proper rotational position during total knee arthroplasty (TKA). The aim of the study was to assess the intra-operative differences in tibial rotation position during computer-navigated primary TKA using either the TTL or ROM techniques. The ROM technique was hypothesized to be a repeatable method and to produce different tibial rotation positions compared to the TTL technique. METHODS: A prospective, observational study was performed to evaluate the antero-posterior axis of the cut proximal tibia using both the ROM and the TTL technique during primary TKA without postoperative clinical assessment. Computer navigation was used to measure this difference in 20 consecutive knees of 20 patients who underwent a posterior stabilized total knee arthroplasty with a fixed-bearing polyethylene insert and a patella resurfacing. RESULTS: The ROM technique is a repeatable method with an interclass correlation coefficient (ICC2) of 0.84 (p < 0.001). The trial tibial baseplate was on average 4.56 degrees externally rotated compared to the tubercle landmark. This difference was statistically significant (p = 0.028). The amount of maximum intra-operative flexion and the pre-operative mechanical axis were positively correlated with the magnitude of difference between the two methods. CONCLUSIONS: It is important for the orthopaedic surgeon to realise that there is a significant difference between the TTL technique and ROM technique when positioning the tibial component in a rotational position. This difference is correlated with high maximum flexion and mechanical axis deviations.

Computer-assisted total knee arthroplasty using mini midvastus or medial parapatellar approach technique: A prospective, randomized, international multicentre trial.

BACKGROUND: Despite the growing evidence in the literature there is still a lack of consensus regarding the use of minimally invasive surgical technique (MIS) in total knee arthroplasty (TKA). METHODS: A prospective, randomized, international multicentre trial including 69 patients was performed to compare computer-assisted TKA (CAS-TKA) using either mini-midvastus (MIS group) or standard medial parapatellar approach (conventional group). Patients from 3 centers (Maastricht, Zwickau, Adelaide) with end-stage osteoarthritis of the knee were randomized to either an MIS group with dedicated instrumentation or a conventional group to receive cruciate retaining CAS-TKA without patella resurfacing. The primary outcome was to compare post operative pain and range of motion (ROM). The secondary outcome was to measure the duration of surgery, blood loss, chair rise test, quadriceps strength, anterior knee pain, Knee Society Score (KSS),WOMAC scores, mechanical leg axis and component alignment. RESULTS: Patients in the MIS group (3.97 ± 2.16) had significant more pain at 2 weeks than patients in the conventional group (2.77 ± 1.43) p = 0.003. There was no significant difference in any of the other primary outcome parameters. Surgery time was significantly longer (p < 0.001) and there were significantly higher blood loss (p = 0.002) in the MIS group as compared to the conventional group. The difference of the mean mechanical leg alignment between the groups was not statistically significant (-0.43° (95% CI -1.50-0.64); p = 0.43). There was no significant difference of component alignment between the two surgical groups with respect to flexion/extension (p = 0.269), varus/valgus (p = 0.653) or rotational alignment (p = 0.485) of the femur component and varus valgus alignment (p = 0.778) or posterior slope (p = 0.164) of the tibial component. CONCLUSION: There was no advantage of the MIS approach compared to a conventional approach CAS-TKA in any of the primary outcome measurements assessed, however the MIS approach was associated with longer surgical time and greater blood loss. MIS-TKA in combination with computer navigation is safe in terms of implant positioning. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT02625311 8 December 2015.

Recurrent patella loosening and extra-articular migration after TKA.

Loosening and subsequent extra-articular migration of the patella component is a rare complication of total knee arthroplasty. We report a case of recurrent aseptic loosening and extra-articular migration of a patella component. Eventually, treatment consisted of removing the patellar component without replacement.

Experimental results of donor site filling for autologous osteochondral mosaicplasty.

PURPOSE: Autologous osteochondral mosaicplasty has become a treatment option for focal chondral and osteochondral defects in recent years. Excessive postoperative bleeding from the donor site was reported as a possible complication of the procedure. The purpose of this study was to investigate different biodegradable materials for donor site filling, which could prevent excessive postoperative bleeding from these sites but would allow reasonable blood clot formation on the articular surfaces of donor tunnels. TYPE OF STUDY: Basic science evaluation. METHODS: In an experimental model, "donor site plugs" made from hydroxylapatite, carbon fiber, polyglyconate-B, compressed collagen, and 2 versions of polycaprolactones were used to fill the bony tunnels created by harvesting. These materials were tested in 100 knees of 50 German Shepherd dogs to determine the quality of the repair tissue formation on the surfaces of the harvesting holes filled by these materials. Arthroscopies of the dogs were performed at several intervals, from 4 weeks to 26 weeks, and macroscopic studies were performed on euthanized animals between 8 weeks and 30 weeks to evaluate donor site filling and coverage. Empty donor tunnels served as controls for the evaluation of the different filling materials. RESULTS: All tested materials effectively decreased postoperative bleeding. Hydroxylapatite, carbon rods, polyglyconate-B, and melted polycaprolactone materials showed a good integration to the surrounding cancellous bone, but these fillings showed only a limited repair tissue formation, even at 30 weeks postoperatively. Second-look arthroscopy and histologic evaluation of necropsies showed the best fibrocartilage coverage after filling by compressed collagen. Technical details of the filling also had certain importance in the quality of the repair tissue formation. CONCLUSIONS: According to histologic results, compressed collagen appears to be a good material to fill donor tunnels of osteochondral graft harvest. This material is substituted gradually by bone formation and its articular surface can serve as an appropriate scaffold for fibrocartilage coverage created by the natural intrinsic repair process.