Discharge Opioid Dose Indirectly Associated With Functional Outcomes 2 Weeks After Shoulder and Knee Arthroscopy in a US Military Sample.

INTRODUCTION: Postsurgical opioid utilization may be directly and indirectly associated with a range of patient-related and surgery-related factors, above and beyond pain intensity. However, most studies examine postsurgical opioid utilization without accounting for the multitude of co-occurring relationships among predictors. Therefore, this study aimed to identify factors associated with opioid utilization in the first 2 weeks after arthroscopic surgery and examine the relationship between discharge opioid prescription doses and acute postsurgical outcomes. METHODS: In this prospective longitudinal observational study, 110 participants undergoing shoulder or knee arthroscopies from August 2016 to August 2018 at Walter Reed National Military Medical Center completed self-report measures before and at 14 days postoperatively. The association between opioid utilization and both patient-level and surgery-related factors was modeled using structural equation model path analysis. RESULTS: Participants who were prescribed more opioids took more opioids, which was associated with worse physical function and sleep problems at day 14, as indicated by the significant indirect effects of discharge opioid dose on day 14 outcomes. Additional patient-level and surgery-related factors were also significantly related to opioid utilization dose and day 14 outcomes. Most participants had opioid medications leftover at day 14. CONCLUSION: Excess opioid prescribing was common, did not result in improved pain alleviation, and was associated with poorer physical function and sleep 14 days after surgery. As such, higher prescribed opioid doses could reduce subacute functioning after surgery, without benefit in reducing pain. Future patient-centered studies to tailor opioid postsurgical prescribing are needed.

Knee extension deficit during gait and knee extensor weakness persisting after saucerization and repair of discoid lateral meniscus tears.

BACKGROUND: Physical function and knee kinematics recovery after discoid lateral meniscus (DLM) tear surgery are essential for a better prognosis. However, these alterations remain unclear. Therefore, this study aimed to investigate changes in physical function and knee kinematics following saucerization and DLM tear repair. METHODS: We enrolled 16 patients who underwent saucerization and DLM tear repair. Postoperative changes in knee kinematics during gait, and physical function, were evaluated at 3, 6, and 12 months. RESULTS: The peak flexion angle of the operated limb during weight acceptance was significantly higher than that of the contralateral limb at 3 (operated limb: 34.6 ± 8.9°, contralateral limb: 23.7 ± 8.3°; P < 0.01) and 6 months (operated limb: 32.1 ± 9.7°, contralateral limb: 24.6 ± 8.2°; P = 0.03) postoperatively, but not at 12 months (operated limb: 27.1 ± 7.1°, contralateral limb: 23.1 ± 9.5°; P = 0.22) postoperatively. The knee extensor strength of the operated limb was significantly lower than that of the contralateral limb at 3 (operated limb: 1.00 ± 0.59 Nm/kg, contralateral limb: 1.37 ± 0.59 Nm/kg; P = 0.01), 6 (operated limb: 1.22 ± 0.55 Nm/kg, contralateral limb: 1.48 ± 0.60 Nm/kg; P < 0.01), and 12 months (operated limb: 1.39 ± 0.57 Nm/kg, contralateral limb: 1.55 ± 0.64 Nm/kg; P = 0.04) postoperatively. CONCLUSION: Knee extension deficits and extensor weakness persisted at 6 months after saucerization and repair of DLM tears. Postoperative rehabilitation should be focused on knee extension function.

Persistent altered knee loading in patients with meniscectomy: A systematic review and meta-analysis.

OBJECTIVES: To determine the changes in knee flexion moment (KFM) and knee adduction moment (KAM) during weight-bearing activities following meniscectomy. DESIGN: Meta-Analysis. SETTING: Laboratory. PARTICIPANTS: 332 meniscectomy patients and 137 healthy controls (from 13 qualified studies) MAIN OUTCOME MEASURES: Cohen's d effect sizes (ESs) were calculated to compare KAM and KFM values of the surgical legs to the non-surgical and to healthy control legs. RESULTS: When compared to healthy controls, meniscectomy patients' surgical legs demonstrated a significantly greater KAM (ES = 0.310; P = 0.002) but no significant difference in KFM (ES = -0.182; P = 0.051). When compared to the patients' non-surgical legs, however, the surgical legs showed no difference in KAM (ES = -0.024; P = 0.716) but a significantly lower KFM (ES = -0.422; P < 0.001). High heterogeneity among study ESs was observed in patients' between-limb comparison for KAM (Q-value = 20.08, P = 0.005; I2 = 65.1%) and KFM (Q-value = 43.96, P < 0.001; I2 = 79.5%). However, no significant differences in study ESs (all P > 0.102) of KFM and KAM were identified when comparing studies with various times post-surgery, weight-bearing tasks, walking speeds, or patient demographics. CONCLUSION: Elevated KAM and reduced/asymmetrical KFM observed in meniscectomy patients may contribute to the increased risk of knee OA. Rehabilitation should focus on movement education to restore between-limb KFM symmetry and reduce KAM bilaterally post-meniscectomy.

A comparison of thrombosis in total knee arthroplasty with and without a tourniquet: a meta-analysis of randomized controlled trials.

BACKGROUND: Tourniquets are widely used in total knee arthroplasty (TKA), but the issue of their safety remains controversial. Previous studies have focused on TKA blood loss, duration of surgery, and hemostatic drugs. The purpose of this meta-analysis was to analyze the effect of tourniquet use on postoperative deep venous thrombosis (DVT). METHODS: PubMed, SCOPUS, Web of Science, Embase, and the Cochrane Library were searched for randomized clinical trials published before April 17, 2020, that compared the effect of tourniquet use on postoperative DVT, knee circumference, D-dimers, and pain measured using the visual analog scale (VAS). RESULTS: Fourteen clinical trials that included 1321 unique participants were included in the meta-analysis. Among the total, 721 and 600 participants were randomized to the tourniquet and non-tourniquet groups, respectively. The incidence of postoperative thrombosis in the tourniquet group was significantly higher than in the non-tourniquet group (RR 2.30, 95% CI 1.51-3.49, P < 0.0001, I2 = 0%). On the 1st, 3rd, and 5th to 21st days, and 3 to 6 weeks after surgery, the knee circumference difference of the tourniquet group was significantly larger than that of the non-tourniquet group (P < 0.05). However, 4 to 6 months after the surgery, no significant difference in knee circumference was found between the two groups (MD 0.14, 95% CI -0.02-0.31, P = 0.09, I2 = 0%). The VAS score of the tourniquet group was higher than the non-tourniquet group on the 3rd and 5th days after surgery (P < 0.05). However, this difference was not significant (MD 0.31, 95% CI -0.05-0.66, P = 0.09, I2 = 89%). CONCLUSION: Results of this meta-analysis indicate that tourniquet application could increase the incidence of postoperative DVT and aggravate postoperative pain and swelling in the short term. LEVEL OF EVIDENCE: Level III.

Patient-specific instrumentation combined with a new tool for gap balancing is useful in total knee replacement: a 3-year follow-up of a retrospective study.

OBJECTIVE: The purpose of this study was to determine whether the gap-balancing technique with patient-specific instrumentation (PSI) and a new balancing device in total knee arthroplasty (TKA) can improve knee function to a greater extent than can the measured resection technique. MATERIALS AND METHODS: Data from 150 patients who underwent TKA from August 2014 to June 2016 were studied retrospectively. The gap-balancing technique assisted by PSI and the new balancing device was used in 80 patients (82 knees), and the measured resection technique was used in 70 patients (70 knees). The surgical, imaging, and knee function data were compared. RESULTS: The gap-balancing technique assisted by PSI and the new balancing device was found to be feasible in all operated knees and reliable. In total, 150 patients (152 knees) of ages ranging from 52 to 78 years (mean 67 years) underwent TKA during the study period. The follow-up period ranged from 35 to 52 months (mean 45 months). Only one patient, who was included in the gap-balancing group, underwent a revision surgery at 2 years postoperatively due to infection. There were no differences in the incidence of anterior knee pain between the two groups. The mean flexion angle, KSS scores, and VAS scores did not significantly differ between the measured resection group and gap-balancing group at 12 weeks or 36 weeks postoperatively. The average joint line displacement was 1.3 ± 1.1 mm (range 0-3) proximally in the GB (gap-balancing) group and 1.2 ± 1.4 mm in the MR (measured-resection) group. No outliers >5 mm in either group were recorded. The mean leg axis deviation from the neutral mechanical axis was 1.8°±1.5° varus (range 0°-3°varus) versus the neutral mechanical axis in the GB group and 1.4°±1.2°(range 0°-3°)in the MR group. No outliers with >3° deviation in either group were recorded. CONCLUSIONS: The gap-balancing technique performed with the new balancing device and PSI can yield accurate femoral component alignment as well as outcomes similar to those of measured resection at 3 years. The new balancing device can be taken into consideration by surgeons who prefer performing the gap-balancing technique with PSI.

Differences in lower-extremity kinematics between the male military personnel with and without plantar fasciitis.

OBJECTIVE: To evaluate the factors that influence gait by comparing lower extremity kinematics during the stance phase of the gait cycle between individuals with and without plantar fasciitis. DESIGN: A cross-sectional study. SETTING: Motion analysis research laboratory. PARTICIPANTS: Thirty subjects with plantar fasciitis and 30 aged-matched controls. MAIN OUTCOME MEASURE(S): Range of motion of the lower extremity and multi-segment foot during gait using a three-dimensional motion analysis system. RESULTS: The plantar fasciitis group showed significant differences in motion in the multi-segment foot, ankle, knee, and hip from the control group during various subphases of the stance phase. Specifically, relative to the control group, the plantar fasciitis group had more rearfoot adduction, forefoot eversion, ankle abduction, and hip abduction. They also had less midfoot dorsiflexion, forefoot dorsiflexion, knee extension, knee external rotation, and hip extension (all Ps < 0.05). CONCLUSIONS: Individuals with plantar fasciitis exhibited more flexibility in the ankle-foot complex and poorer quality of lower-extremity movement than the group that did not have plantar fasciitis. Thus, differences in structures in both the ankle-foot complex as well as those in the hip and knee joints appear to be associated with the presence of plantar fasciitis.

Long-term survivorship of total knee arthroplasty with a single-radius, high-flexion posterior stabilized prosthesis.

BACKGROUND: The purpose of this study was to determine functional outcomes, implant survival rate, and complications of a single-radius, high-flexion posterior stabilized (PS) total knee prosthesis at a minimum follow up of 10 years for a consecutive series. METHODS: This retrospective observational study included 395 consecutive patients who underwent 585 single-radius, PS total knee arthroplasties (TKAs) between January 2009 and December 2009. Their functional outcomes, implant survival rates, radiological findings, and complications were evaluated. RESULTS: At a mean follow up of 11.2 years (range, 10.6-11.8 years), 395 (80.8%) patients were available for review. At final follow up, preoperative Knee Society knee scores were improved from 37.3 to 80.1 (P < 0.05) and function scores were improved from 35.7 to 80.5 points (P < 0.05). Sixteen knees (2.7%) in 15 patients required revision surgery due to 11 septic loosening (1.9%) and five aseptic loosening events (0.8%). Cumulative survival for the prosthesis was 97.3% for any cause at 10 years. A total of 34 radiolucent lines (5.8%) were detected an average of 2.4 years following surgery and radiological assessment did not reveal any evidence of component migration at final follow up. CONCLUSIONS: Single-radius, high-flexion PS TKA showed good long-term survival rates and clinical outcomes. Further study is required to determine whether limited radiolucency findings at the tibial component-tibial plateau could progress to or result in the loosening of components.

A longitudinal investigation of landing biomechanics following anterior cruciate ligament reconstruction.

OBJECTIVE: Abnormal movement patterns have been shown during landing in patients who have undergone anterior cruciate ligament (ACL) reconstruction surgery. The purpose of this study was to investigate landing biomechanics over time in this patient group to determine whether asymmetry between limbs reduced with time and after a return to physical activity. DESIGN: Prospective longitudinal study. SETTING: Biomechanics laboratory. PARTICIPANTS: Fourteen patients who had undergone ACL reconstruction surgery. MAIN OUTCOME MEASURE: Single limb landing assessments were made at two time points; within the first year (mean of 10 months) and at 3 years (after patients had returned to sport) following ACL reconstruction. Three-dimensional motion analysis was used to record kinematic and kinetic variables, which were compared across time and limb using ANOVA models. RESULTS: Most biomechanical variables showed little change over time except for the external knee adduction moment at the operated knee, which increased (effect size d = 0.5), but remained less than the contralateral side. In the sagittal plane, asymmetrical landing patterns were seen at both assessments. Patients landed with reduced knee flexion angles (effect size range 0.76-0.9) and moments (effect size range 0.56-0.9) compared to the uninjured limb and made compensations for this by increasing the hip flexion moment (effect size range d = 0.6-0.75). CONCLUSIONS: Asymmetrical landing biomechanics persisted at three years after ACL reconstruction in athletes who returned to sporting activity. Long term implications of controlling the landing by increasing the hip moment are unknown and require further investigation.

Commonly used clinical criteria following ACL reconstruction including time from surgery and isokinetic limb symmetry thresholds are not associated with between-limb loading deficits during running.

OBJECTIVES: We included objective measures of gait and functional assessments to examine their associations in athletes who had recently commenced running after ACL reconstruction. DESIGN: Cross-sectional. SETTING: Sports medicine. PARTICIPANTS: 65 male athletes with a history of ACL reconstruction. MAIN OUTCOME MEASURES: Time from surgery, isokinetic knee extension/flexion strength (60°/s), and peak vertical ground reaction force (pVGRF) measured during running using an instrumented treadmill. We also investigated if a range of recommended isokinetic thresholds (e.g. > 70% quadriceps limb symmetry index) affected the magnitude of pVGRF asymmetry during running. RESULTS: There were significant relationships between quadriceps (r = 0.50) and hamstrings (r = 0.46) peak torque and pVGRF. Quadriceps peak torque explained a quarter of the variance in pVGRF (R2 = 0.24; p < 0.001). There was no association was between running pVGRF and time from surgery. Between-group differences in running pVGRF LSI% were trivial (d < 0.20) for all quadriceps and hamstring peak torque LSI thresholds. CONCLUSIONS: Current clinical criteria including time from surgery and isokinetic strength limb symmetry thresholds were not associated with lower pVGRF asymmetry measured during running. Quadriceps strength is important, but 'minimum symmetry thresholds' should be used with caution.

Gap balancing improve squat function and knee function: a randomized controlled trial comparing gap balancing and measured resection.

OBJECTIVE: We compared the measured resection (MR) technique and the gap balancing (GB) technique in patients with knee osteoarthritis after primary total knee arthroplasty (TKA) in China to understand the effects of the two techniques on knee function and squat function. METHODS: From March 2017 to September 2019, a prospective randomized controlled trial was conducted with 96 patients with knee osteoarthritis undergoing primary TKA from March 2017 to September 2019 randomized to GB group (n = 48) and MR group (n = 48). Intraoperative indicators (operation time, osteotomy volume of medial and lateral of posterior femoral condyles, external rotation angle) were recorded during operation. At 1, 3, 6, and 12 months after surgery, all the patients came to the hospital for review and underwent the pain severity, Western Ontario and McMaster University Osteoarthritis Index (WOMAC), knee joint range of motion, Oxford Knee Score (OKS), and American Knee Society Score (AKSS) tests. All patients were followed up for more than 1 year. RESULTS: The osteotomy volume of the medial femoral condyle in the GB group was higher than that in the MR group (P<0.05), and the operation time in the GB group was shorter than that in the MR group (P<0.05). At 1, 3, 6, and 12 months after surgery, the pain severity in the GB group was lower than that in the MR group (P<0.05), the knee range of motion in the GB group was larger than that in the MR group (P<0.05), the WOMAC of the GB group was lower than that of the MR group (P<0.05), the OKS of the GB group was higher than that of the MR group (P<0.05), the AKSS of the GB group was higher than that of the MR group. The incidence of postoperative complications in the GB group (4.17%) was significantly lower than that in the MR group (18.75%) (P<0.05). CONCLUSION: The GB technique can effectively shorten the operation time, relieve pain, improve knee range of motion, improve squat function and knee function, reduce osteoarthritis index, and reduce the occurrence of complications, which is worthy of clinical popularization and application.

Extreme stiff knee recurvatum following manipulation under anesthesia and botulinum neurotoxin injection.

In this article we report a case of stiff, neglected extreme recurvatum knee deformity in a 17-year-old female. This is the first reported case in the literature of an acquired ligamentous stiff extreme knee recurvatum following manipulation under anesthesia and botulinum neurotoxin injection. Μodified Judet quadricepsplasty combined with Ilizarov external hinged frame fixation was implemented. This dual technique can be considered as a rational approach for such an extreme deformity as it stabilizes, progressively corrects, and prevents recurrence. A patellar tendon rupture caused by the increasing tension of the extensor mechanism following the correction was treated successfully using a cadaveric Achilles tendon allograft.

Poor diet quality is associated with self-reported knee pain in community-dwelling women aged 50 years and older.

In the current study, we aimed to examine the association between knee pain and diet quality in women aged ≥ 50 years using data from the Korea National Health and Nutrition Examination Survey. This was a population-based, cross-sectional study. Diet quality was assessed using the Diet Quality Index-International (DQI-I), and knee pain and osteoarthritis were self-reported. A multivariate logistic regression model was used to adjust for age, body mass index, household income, marital status, education, occupation, smoking status, hazardous alcohol use, regular physical activity, menopause, and chronic diseases, including hypertension, diabetes, dyslipidemia, osteoarthritis, and depression. A total of 3,881 women were included in this study, and the prevalence of knee pain was 25.4%. The intakes of total energy, protein, and fat were lower in women with knee pain than in those without (all P < 0.01), while the carbohydrate intake was higher (P = 0.01). No significant differences were noted in the scores for variety, overall balance, and moderation components, except for the item of total fat intake, between the DQI-I scores for women with and without knee pain, after adjusting for age. Women without knee pain showed higher scores in several items of the adequacy component (P < 0.05) than did women with knee pain. The total DQI-I scores were lower in women with knee pain than in women without knee pain, after adjusting for covariates, including osteoarthritis (OR = 0.985, 95% CI = 0.973-0.997, P = 0.01). Knee pain independent of osteoarthritis was associated with poor diet quality in community-dwelling women aged ≥ 50 years.

Effectiveness of Salvage Knee Rotationplasty on Sarcoma Around the Knee in Adolescents and Young Adults.

BACKGROUND/AIM: This study aimed to investigate the effectiveness of knee rotationplasty (KRP) as salvage surgery for uncontrolled infection and implant failure of total knee arthroplasty (TKA) for sarcoma around the knee in adolescents and young adults (AYA). PATIENTS AND METHODS: This retrospective cohort study included 33 patients who underwent KRP and were grouped based on the treatment received: initial surgery for sarcoma around the knee (n=18) or as salvage surgery (n=15). Musculoskeletal Tumor Society (MSTS) score, range of motion (ROM) and postoperative results were analyzed. RESULTS: All 15 patients who underwent salvage KRP had TKA as an initial surgery. Although there were five infections in salvage KRP, which originated from the initial TKA, all cases were controllable, no implant failure occurred. MSTS score and ROM were deemed acceptable in both groups. CONCLUSION: Salvage KRP is an effective option for uncontrolled complications of initial TKA for sarcoma around the knee.

Correction of coronal plane deformities around knee in children with two-hole tension band plates.

OBJECTIVES: This study aims to present the 10-year results and complications of two-hole tension band plate hemiepiphysiodesis for coronal deformities around knee in a large population from a single center. PATIENTS AND METHODS: Seventy-seven patients (46 boys, 31 girls; mean age 93±36 months; range, 22 to 181 months) who underwent temporary hemiepiphysiodesis around knee between January 2009 and January 2019 with two-hole tension band plates were retrospectively evaluated. Improvement of joint orientation angles and mechanical axis deviations, deformity correction rates, etiology groups, and complications were noted. RESULTS: A total of 166 bone segments (93 femurs, 73 tibias) were included in the study. Mean follow-up duration after the implantation was 36±17 (range, 12 to 88) months. Plates were removed at mean 18±8 (range, 7 to 47) months of implantation. Of the bone segments, 95.2% (n=158) responded successfully to the plates. Mean correction rate of mechanical lateral distal femoral angle in femoral valgum deformity was 0.94±0.43° (range, 0.17 to 2.22)/month and mean correction rate of mechanical medial proximal tibial angle in tibial valgum deformity was 0.62±0.36° (range, 0.11 to 1.55)/month. Mean correction rate of mechanical lateral distal femoral angle in femoral varum deformity was 1.3±0.8° (range, 0.48 to 2.92)/month and mean correction rate of mechanical medial proximal tibial angle in tibial varum deformity was 0.94±0.49° (range, 0.26 to 1.67)/month. The most common complication observed was rebound deformity seen in 41.2% (n=70) of the bone segments. Nine bone segments had persistent hemiepiphysiodesis despite plate removal. Four screw breakages (three metaphysial and one epiphysial) were observed. CONCLUSION: Two-hole tension band plate hemiepiphysiodesis appears to be an effective and safe method for the correction of coronal deformities around knee.

Weight-bearing status affects in vivo kinematics following mobile-bearing unicompartmental knee arthroplasty.

PURPOSE: The effects of weight bearing (WB) on knee kinematics following mobile-bearing unicompartmental knee arthroplasty (UKA) remain unknown. The purpose of this study was to clarify the effects of WB on in vivo kinematics of mobile-bearing UKA during high knee flexion activities. METHODS: The kinematics of UKA were evaluated under fluoroscopy during squatting (WB) and active-assisted knee flexion (non-weight bearing, NWB). Range of motion, femoral axis rotation relative to the tibia, anteroposterior (AP) translation of the medial and lateral sides, and kinematic pathway were measured. RESULTS: There were no differences in knee flexion range and external rotation of the femur in each flexion angle between the WB conditions. The amount of femoral external rotation between minimum flexion and 60° of flexion during WB was significantly larger than that during NWB, and that between 60° and 130° of flexion during NWB was significantly larger than that during WB. There were no differences in medial AP translation of the femur in each flexion angle between the WB conditions. However, on the lateral side, posterior translation of 52.9 ± 12.7% was observed between minimum flexion and 130° of flexion during WB. During NWB, there was no significant translation between minimum flexion and 60° of flexion; beyond 60° of flexion, posterior translation was 41.6 ± 8.7%. Between 20° and 80° of flexion, the lateral side in WB was located more posteriorly than in NWB (p < 0.05). CONCLUSION: Mobile-bearing UKA has good anterior stability throughout the range of knee flexion. WB status affects the in vivo kinematics following mobile-bearing UKA. LEVEL OF EVIDENCE: III.

A cruciate-retaining implant can treat both knees of most windswept deformities when performed with calipered kinematically aligned TKA.

PURPOSE: Surgeons performing total knee arthroplasty (TKA) on the osteoarthritic valgus deformity often use a posterior stabilized (PS) and semi-constrained implants to substitute for the release of a contracted posterior cruciate ligament (PCL) instead of a cruciate retaining (CR) implant. Calipered kinematic alignment (KA) strives to retain the PCL and use a CR implant. The aim of this study of the windswept deformity was to determine whether the level of implant constraint, outcome scores, and alignment after bilateral calipered KA TKA are different between a pair of knees with a varus and valgus deformity in the same patient. METHODS: A review of a prospectively collected database identified all patients with a windswept deformity treated with bilateral TKA (n = 19) out of 2430 consecutive primary TKAs performed between 2014 and 2019. Operative reports determined the level of implant constraint. Patient response to the Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) assessed outcomes at a mean follow-up of 2.3 years. Postoperative alignment was measured on an A-P computer tomographic scanogram of the limb. RESULTS: CR implants were used in 15 of 19 (79%) valgus deformities and 17 of 19 (89%) of varus deformities (n.s.). No knees required a semi-constrained implant. There was no difference in the median postoperative FJS and OKS (n.s.), and a 1° or less difference in the mean postoperative distal lateral femoral angle (p = 0.005) and proximal medial tibial angle (n.s.) between the paired varus and valgus knee deformity. CONCLUSION: Based on this small series, surgeons that use calipered KA TKA can expect to use CR implants in most patients with windswept deformity and achieve comparable outcome scores and alignment between the paired varus and valgus deformity. LEVEL OF EVIDENCE: IV.

Influence of component design on in vivo tibiofemoral contact patterns during kneeling after total knee arthroplasty: a systematic review and meta-analysis.

PURPOSE: Modern TKR prostheses are designed to restore healthy kinematics including high flexion. Kneeling is a demanding high-flexion activity. There have been many studies of kneeling kinematics using a plethora of implant designs but no comprehensive comparisons. Visualisation of contact patterns allows for quantification and comparison of knee kinematics. The aim of this systematic review was to determine whether there are any differences in the kinematics of kneeling as a function of TKR design. METHODS: A search of the published literature identified 26 articles which were assessed for methodologic quality using the MINORS instrument. Contact patterns for different implant designs were compared at 90° and maximal flexion using quality-effects meta-analysis models. RESULTS: Twenty-five different implants using six designs were reported. Most of the included studies had small-sample sizes, were non-consecutive, and did not have a direct comparison group. Only posterior-stabilised fixed-bearing and cruciate-retaining fixed-bearing designs had data for more than 200 participants. Meta-analyses revealed that bicruciate-stabilised fixed-bearing designs appeared to achieve more flexion and the cruciate-retaining rotating-platform design achieved the least, but both included single studies only. All designs demonstrated posterior-femoral translation and external rotation in kneeling, but posterior-stabilised designs were more posterior at maximal flexion when compared to cruciate retaining. However, the heterogeneity of the mean estimates was substantial, and therefore, firm conclusions about relative behaviour cannot be drawn. CONCLUSION: The high heterogeneity may be due to a combination of variability in the kneeling activity and variations in implant geometry within each design category. There remains a need for a high-quality prospective comparative studies to directly compare designs using a common method. LEVEL OF EVIDENCE: Systematic review and meta-analysis Level IV.

Tibiofemoral subluxation in the coronal plane does not affect WOMAC and KOOS after total knee arthroplasty.

PURPOSE: To investigate the effect of preoperative coronal tibiofemoral subluxation (CTFS) on functional outcome, prosthesis type, insert thickness and revision rates in patients who underwent total knee arthroplasty (TKA). METHODS: A total of 224 knees of 186 patients were included. Patients were divided into two groups as either with (Group 1, 114 knees of 86 patients) or without (Group 2, 124 knees of 100 patients) coronal lateral tibiofemoral subluxation. The mean follow-up period was 71.3 ± 7.3 (range 60-84) months in group 1 and 69.4 ± 6.6 (range 61-79) months in group 2 (n.s.). Coronal tibiofemoral subluxation degree was measured in degrees on standing anteroposterior knee radiographs. Group 1 was divided into three subgroups according to amount of subluxation (< 5 mm, 6-10 mm and > 10 mm). Functional outcome was evaluated using the Western Ontario and McMaster Osteoarthritis Index (WOMAC) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at the last follow-up visit. Prosthesis type, insert thickness and revision rates were compared between the two groups. RESULTS: There were no significant differences between the two groups regarding patient demographics, prosthesis type, and revision rates (n.s.). The insert thickness was found significantly higher in group 1 (p < 0.001). The preoperative and postoperative WOMAC and KOOS scores were found no significantly different between the two groups (n.s.). Among subluxation (+) subgroups, there was no significant difference in functional outcome scores and revision rates (n.s.). However, prosthesis type and insert thickness were significantly associated with the amount of subluxation (p = 0.009 and p = 0.001, respectively). There was no significant correlation between the degree of lower extremity deformity and coronal tibiofemoral amount of subluxation (n.s.). CONCLUSION: Preoperative CTFS does not adversely affect the WOMAC score, KOOS and revision rates after TKA. In the clinical practice, surgeons should be aware of the need for a posterior cruciate stabilizing prosthesis and a thicker insert in the presence of CTFS, especially with subluxation greater than 10 mm and to consider a spared bony resection on the tibia in patients suffering from CTFS. LEVEL OF EVIDENCE: IV.

Evolving evidence in the treatment of primary and recurrent posterior cruciate ligament injuries, part 1: anatomy, biomechanics and diagnostics.

The posterior cruciate ligament (PCL) represents an intra-articular structure composed of two distinct bundles. Considering the anterior and posterior meniscofemoral ligaments, a total of four ligamentous fibre bundles of the posterior knee complex act synergistically to restrain posterior and rotatory tibial loads. Injury mechanisms associated with high-energy trauma and accompanying injury patterns may complicate the diagnostic evaluation and accuracy. Therefore, a thorough and systematic diagnostic workup is necessary to assess the severity of the PCL injury and to initiate an appropriate treatment approach. Since structural damage to the PCL occurs in more than one third of trauma patients experiencing acute knee injury with hemarthrosis, background knowledge for management of PCL injuries is important. In Part 1 of the evidence-based update on management of primary and recurrent PCL injuries, the anatomical, biomechanical, and diagnostic principles are presented. This paper aims to convey the anatomical and biomechanical knowledge needed for accurate diagnosis to facilitate subsequent decision-making in the treatment of PCL injuries.Level of evidence V.

Simple Knee Value: a simple evaluation correlated to existing knee PROMs.

PURPOSE: The Simple Knee Value (SKV) is an outcome score in which patients are asked to grade their knee function as a percentage of that of a normal knee. The primary aim of this study was to validate the SKV by measuring its correlation with existing knee-related PROMs. METHODS: This was a prospective study conducted at a teaching hospital to assess the SKV's validity. The study enrolled 47 young patients (16-54 years old), 49 older patients (≥ 55 years) and 30 healthy controls. A paper questionnaire consisting of the Lysholm, IKDC, KOOS, WOMAC and SKV was given to subjects three times (enrolment, 1-month preoperative visit and 6 months postoperative visit). The criterion validity of the SKV was determined by correlating it to existing knee PROMs using the Spearman correlation coefficient (S). SKV test-retest reliability was assessed by the intraclass correlation coefficient (ICC) between two time points (initial consultation at enrolment and preoperative visit, reflecting the same clinical condition). Responsiveness to change was determined by comparing the SKV scores before and after surgery (enrolment consultation and 6 months postoperative). Discriminative ability was determined by comparing the SKV distribution in patients and controls. RESULTS: There was a strong and significant correlation between the SKV and the gold standard Lysholm, IKDC, KOOS and WOMAC in the younger patients and the older patients (p < 0.0001). The reliability between the SKV at the initial consultation and before surgery was excellent (ICC 0.862, 95% CI 0.765; 0.921) in the younger patients, and moderate (ICC 0.506, 95% CI 0.265; 0.688) in the older patients. The SKV was responsive to change in both patient groups (p < 0.0001 for the SKV before versus 6 months after surgery). Like the other knee-specific PROMs (p < 0.0001), the SKV was able to distinguish between patients and controls (p < 0.0001). CONCLUSIONS: The SKV is valid as it is significantly correlated to existing knee PROMs. It is also reliable, responsive to change and discriminating. Its simplicity gives it many advantages and it can be used by physicians in their daily practice. LEVEL OF EVIDENCE: Level II.