The association of knee injury and obesity with unilateral and bilateral osteoarthritis of the knee

The prevalence of bilateral and ipsilateral radiographic osteoarthritis is high in White, Asian and Native Hawaiian/Pacific Islanders presenting for unilateral knee or hip arthroplasty

BACKGROUND

It is estimated that one-third of patients presenting with unilateral joint pain have contralateral osteoarthritis (OA) at first presentation. Most studies have primarily examined White patient cohorts. The purpose of this study was to determine the prevalence of contralateral joint OA for patients presenting for unilateral total knee (TKA), unicompartmental knee (UKA) or total hip arthroplasty (THA) among Asian, Native Hawaiian/Pacific Islander and White patients.

METHODS

Bilateral radiographic reports at initial presentation of 2,312 subjects who underwent unilateral arthroplasties (332 UKAs, 933 TKAs and 1,047 THAs) were reviewed. The presence of contralateral OA was recorded and compared by racial group and type of arthroplasty performed. Parametric statistical analyses were performed to determine differences between groups. Multivariable analyses were completed for each arthroplasty group to determine the influence on the presence of contralateral OA, presented as odds ratios and 95% confidence intervals.

RESULTS

Contralateral joint OA was present in 86.7%, 90.4% and 70.4% of UKA, TKA and THA patients, respectively. Concurrent hip OA was present in 41.6% and 59.5% of UKA and TKA patients. No racial differences in the prevalence of contralateral knee OA were found for knee arthroplasty patients. White patients (74.6%) had a greater prevalence of contralateral hip OA compared to Asians (66.5%, p = 0.037) amongst THA recipients. Increased age and body mass index were significantly associated with the presence of contralateral knee OA. Increased age, being male and being White were significant contributors for the presence of contralateral hip OA.

CONCLUSION

The prevalence of contralateral joint OA and concurrent hip OA is high in all three racial groups. Due to the extensive prevalence of contralateral and concurrent knee and hip OA, bilateral radiographic evaluation should be considered for all patients presenting with unilateral hip or knee pain due to OA.

Contralateral knee osteoarthritis is a risk factor for ipsilateral knee osteoarthritis progressing: a case control study

BACKGROUND

Knee osteoarthritis (KOA) is a highly disabling disease, and studying its progression is crucial. However, it is still unclear whether the progression of ipsilateral knee osteoarthritis is influenced by contralateral knee osteoarthritis.

METHODS

Data were collected from the OAI database and divided into two study cohorts (right/left KOA cohort). Each cohort had a target knee (right/left knee) and was further divided into two groups (exposure/control group). The demographic data of both cohorts were balanced at baseline by propensity score matching (PSM), and the data included rating scale and radiographic and clinical data. After checking for balance in the matched variables, we then compared the differences between the two groups in each cohort. Our primary focus was on the minimum joint space width (mJSW) of the target knee, which was measured four years after baseline. The secondary outcome was the arthroplasty rate of the target knee within nine years.

RESULTS

In this study, a total of 678 participants were enrolled and matched. After 1:1 PSM of the baseline demographic data, 98 participants in the right KOA cohort (RKOAC) were successfully matched, and 117 participants in the left KOA cohort (LKOAC) were successfully matched. Furthermore, the standardized mean difference (SMD) of the matched variables in both cohorts was less than 0.25. After analyzing the outcome metrics, we found that the target knee had a significantly lower mJSW in the fourth year after baseline and a significantly greater arthroplasty rate within nine years in the exposed group than in the control group. RKOAC: mJSW (exposure: 2.6(1.1 ~ 3.6) vs. control: 3.3(2.0 ~ 4.2), P < 0.05), arthroplasty rate (exposure: 14(14.3%) vs. control: 4(4.1%), P < 0.05); LKOAC: mJSW (exposure: 3.1(2 ~ 3.9) vs. control: 3.4(2.6 ~ 4.2), P < 0.05), arthroplasty rate (exposure: 16(13.7%) vs. control: 7(6%), P < 0.05).

CONCLUSIONS

Patients with knee osteoarthritis experienced greater progression of osteoarthritis when the contralateral knee was also affected.

Chronic neck pain is associated with increased mortality in individuals with osteoarthritis: results from the NHANES database prospective cohort study

BACKGROUND

Neck pain (NP) is a common symptom reported in the elderly. However, no study has examined the relationship between NP and osteoarthritis (OA) so far, and this study aimed to investigate the association of neck pain with the prevalence and mortality of OA.

METHODS

A total of 5965 participants were included in this cohort study based on the National Health and Nutrition Examination Survey data set of the USA (NHANES). Death outcomes follow-up information was ascertained by linkage to National Death Index (NDI). The association between NP and OA was studied by multi-various logistic regression models after adjusting for potential confounding factors. Cox proportional hazards models were used to elucidate the relationship between NP and all-cause mortality in OA patients.

RESULTS

Among all participants, 8.18% had osteoarthritis, and 5.92% suffered from neck pain. Neck pain was associated with osteoarthritis [1.932 (1.232, 3.028), p < 0.01], which still reminded significant after adjustments [2.519 (1.325, 4.788), p < 0.01] and stratified analysis by sex, race, and smoke status. In OA patients, chronic neck pain (over 1 year) was significantly associated with higher risks of all-cause mortality before [2.94 (1.61, 5.37), p < 0.01] and after adjustment [3.30 (1.23, 45.85), p < 0.05].

CONCLUSION

Neck pain was strongly associated with osteoarthritis. Moreover, chronic neck pain over 1 year significantly increased the mortality of OA patients. Our study demonstrates the need to screen osteoarthritis in the neck pain population and select a more appropriate treatment strategy promptly for those patients.

Culture-expanded mesenchymal stromal cell therapy: does it work in knee osteoarthritis? A pathway to clinical success

Osteoarthritis (OA) is a degenerative multifactorial disease with concomitant structural, inflammatory, and metabolic changes that fluctuate in a temporal and patient-specific manner. This complexity has contributed to refractory responses to various treatments. MSCs have shown promise as multimodal therapeutics in mitigating OA symptoms and disease progression. Here, we evaluated 15 randomized controlled clinical trials (RCTs) and 11 nonrandomized RCTs using culture-expanded MSCs in the treatment of knee OA, and we found net positive effects of MSCs on mitigating pain and symptoms (improving function in 12/15 RCTs relative to baseline and in 11/15 RCTs relative to control groups at study endpoints) and on cartilage protection and/or repair (18/21 clinical studies). We examined MSC dose, tissue of origin, and autologous vs. allogeneic origins as well as patient clinical phenotype, endotype, age, sex and level of OA severity as key parameters in parsing MSC clinical effectiveness. The relatively small sample size of 610 patients limited the drawing of definitive conclusions. Nonetheless, we noted trends toward moderate to higher doses of MSCs in select OA patient clinical phenotypes mitigating pain and leading to structural improvements or cartilage preservation. Evidence from preclinical studies is supportive of MSC anti-inflammatory and immunomodulatory effects, but additional investigations on immunomodulatory, chondroprotective and other clinical mechanisms of action are needed. We hypothesize that MSC basal immunomodulatory "fitness" correlates with OA treatment efficacy, but this hypothesis needs to be validated in future studies. We conclude with a roadmap articulating the need to match an OA patient subset defined by molecular endotype and clinical phenotype with basally immunomodulatory "fit" or engineered-to-be-fit-for-OA MSCs in well-designed, data-intensive clinical trials to advance the field.

Comparative effectiveness of early initiation of oral nonsteroidal anti-inflammatory drug and oral acetaminophen therapies on the time to knee replacement in patients with knee osteoarthritis in Japan

BACKGROUND

Although disease-modifying properties of nonsteroidal anti-inflammatory drugs (NSAIDs) for osteoarthritis (OA) have been reported, the effects of NSAIDs on OA progression remain controversial. The purpose of this study was to investigate the effect of early initiation of oral NSAID therapy on the progression of knee OA.

METHODS

In this retrospective cohort study, we extracted data of patients newly diagnosed with knee OA between November 2007 and October 2018 from a Japanese claims database. The primary outcome was the time to knee replacement (KR), and the secondary outcome was the time to composite event including joint lavage and debridement, osteotomy, or arthrodesis in addition to KR. Weighted Cox regression analysis with standardized mortality/morbidity ratio (SMR) weight was performed to compare the outcomes between patients prescribed oral NSAID (NSAID group) and those prescribed oral acetaminophen (APAP) (APAP group) early after a diagnosis of knee OA. Propensity scores were calculated using logistic regression conditioned on potential confounding factors, and SMR weights were calculated using the propensity scores.

RESULTS

The study population comprised 14,261 patients, who were divided into two groups as follows: 13,994 in the NSAID group and 267 in the APAP group. The mean ages of patients in the NSAID and APAP groups were 56.9 and 56.1 years, respectively. Furthermore, 62.01% and 68.16% patients in the NSAID and APAP groups, respectively, were female. The NSAID group had a reduced risk of KR compared with the APAP group in the analysis using SMR weighting (SMR-weighted hazard ratio, 0.19; 95% confidence interval, 0.05-0.78). While no statistically significant difference was found for the risk of composite event between the two groups (SMR-weighted hazard ratio, 0.56; 95% confidence interval, 0.16-1.91).

CONCLUSIONS

The risk of KR in the NSAID group was significantly lower than that in the APAP group after accounting for residual confounding using SMR weighting. This finding suggests that oral NSAID therapy early after the initial diagnosis is associated with a reduced risk of KR in patients with symptomatic knee OA.

Volume index as a new measure of cartilage loss: a retrospective MRI-based study of chondral injury patterns in adult patients with knee pain

BACKGROUND

Knee pain is one of the commonest symptoms in patients who attend the Orthopaedic outpatient clinics. Chondral defects result in a painful knee. Incidence of chondral defect is reported to be between 5 and 10% over the age of 40. It is well documented that chondral defects can lead to osteoarthritis. Early detection of these lesions and cartilage repair surgery can delay the onset of osteoarthritis. The purpose of this study is to highlight the incidence, associations and correlations between opposing cartilage defects in patients who present to the knee clinic with pain.

METHODS

A retrospective analysis was carried out on patients who had Magnetic Resonance Imaging scans for painful knees between June 2017 and May 2019. About 227 consecutive knees were studied for the incidence of chondral defects, number of lesions, grade and size of lesion, geographical location and associated pathology in the knee.

RESULTS

All the 227 patients had chondral lesions. Most patients had 2-3 lesions (66.1%) with patellar lesions (76.6%) being the commonest followed by medial femoral condyle (59.9%). Significant correlation was found in grade and size between opposing surface lesions in patella-trochlea, Medial Femoral Condyle-Medial Tibial Plateau and Lateral Femoral Condyle-Lateral Tibial Plateau. Females were more predisposed to patella lesions. Significance between age and lesions were established.

CONCLUSION

Incidence of cartilage defects in the knee is very high. Kissing lesions must be considered when treating cartilage lesions. Volume index could be a promising method to quantify lesions.

Short Interval Staged Bilateral Total Knee Arthroplasty: Safety Compared to Simultaneous and Later Staged Bilateral Total Knee Arthroplasty

BACKGROUND

Simultaneous bilateral total knee arthroplasty (sim-BTKA) is reported to be safe in a select group of patients. Patients with symptomatic bilateral knee arthritis who are not candidates for sim-BTKA require staged surgery (stag-BTKA). This study aimed to compare the safety and complications associated with sim-BTKA with stag-BTKA performed at 2 time intervals.

METHODS

This retrospective study of prospectively collected data includes bilateral TKA cases performed between 2001 and 2019. A cohort of sim-BTKA (n = 2728) was compared to a cohort of stag-BTKA (n = 1658). The staged group was subdivided according to the interval between surgeries: ≤90 days (early) and ≥91 days (later). Multivariate logistic regression analyses were used to adjust for confounding variables.

RESULTS

In-hospital complication rates were lower in both arms of the stag-BTKA groups vs the sim-BTKA. The sim-BTKA group had higher odds ratio of anemia, electrolyte disturbances, pulmonary embolism, and respiratory, urinary, gastrointestinal, and neurological complications. Lower rates of all-cause revision were found in stag-BTKA vs sim-BTKA groups. There was a trend toward revision due to deep infection when increasing the interim before the second stag-BTKA procedure. No differences in complication rates after the second surgery were detected between the early and later stag-BTKA.

CONCLUSION

This study demonstrates that sim-BTKA is associated with more complications and revisions when compared to stag-BTKA. Performing the second-stage TKA at 90 days or less after the first TKA is not associated with increased risk of complications. Performing sim-BTKA, simply for convenience, is not warranted and should be reserved for a select group of patient matching specific criteria.

Effects of Isometric Strengthening Exercises on Pain and Disability Among Patients With Knee Osteoarthritis

Introduction

Osteoarthritis (OA) is the most common form of arthritic disease of the joint worldwide, with the knee joint being the most affected in the body. This study investigated the effects of isometric strengthening exercises on pain and disability among patients with knee osteoarthritis.

Methods

This randomized control trial research design was carried out at the Physiotherapy Departments of Nnamdi Azikiwe University Teaching Hospital, Nnewi, and Chukwuemeka Odumegwu Ojukwu University Teaching Hospital, Amaku, Awka in Anambra State, Nigeria. A total of 40 subjects, nine (22.5%) males and 31 (75.5%) females, were randomly assigned into exercise and control groups. Prior to intervention, the weight and height of each subject were measured. Pain intensity, active range of motion (AROM) and passive range of motion (PROM), and functional ability of both groups were recorded using the Numerical Pain Rating Scale (NPRS), universal goniometer, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. All participants in the exercise group performed isometric quadriceps and straight leg raise exercises, and the control group received no intervention whatsoever. After six weeks, the pain intensity, AROM, PROM, and functional ability scores were re-measured and documented.

Results

While comparing the pre-test and post-test scores using paired t-test, the exercise group showed a significant difference in each parameter (NPRS, AROM, PROM, and WOMAC = 0.000), while the control group showed no significant difference. Independent sample t-test outcome at six weeks (exercise and control groups) showed significant reduction of pain intensity (NPRS = 0.000), increased range of motion (AROM = 0.000, PROM = 0.003), as well as improvement in function (WOMAC = 0.000) at a significant level of p ˂ 0.05.

Conclusion

At the end of the six weeks, isometric strengthening exercises showed a significant effect on pain intensity, range of motion, and functional ability among subjects with knee osteoarthritis.

Trends of Obese and Morbidly Obese Patients in Same-Day Bilateral Total Knee Arthroplasty from 2009 to 2016

As obesity in the United States increases, the proportion of obese and morbidly obese patients undergoing same-day bilateral total knee arthroplasty (sd-BTKA) remains unknown. Therefore, this study analyzed: (1) incidence, (2) patient demographics, (3) patient course, and (4) patient outcomes in obese and morbidly obese patients undergoing sd-BTKA in the United States from 2009 to 2016. The National Inpatient Sample was queried for all sd-BTKA patients from 2009 to 2016, yielding 39,901 obese and 20,394 morbidly obese patients. Analyzed variables included overall incidence, age, length of stay (LOS), sex, race, payer, Charlson comorbidity index (CCI) status, disposition, complications, location/teaching status, region of hospital, costs, and charges. Categorical variables were evaluated with chi-square analysis, while continuous variables were analyzed by Student's t-tests. Overall, the number of sd-BTKAs decreased over the study period, although the proportion of both obese and morbidly obese patients increased (p < 0.001 for all). The most common CCI status, 3 + , decreased in proportion for both groups (p < 0.001 for all). Hospital costs decreased and charges increased for both groups (p < 0.001 for all). Mean LOS decreased and patients were most commonly discharged to skilled nursing facilities, although these proportions decreased (p < 0.001 for all). Respiratory failures (p < 0.001 for all) increased for both groups, while proportion of deep vein thromboses and hematomas/seromas (p < 0.001 for all) increased for obese patients and proportion of pulmonary emboli (p < 0.001) increased for morbidly obese patients. The results of this study appear to portray improving optimization and patient selection of higher body mass index (BMI) individuals undergoing this procedure. More information is needed comparing the safety of the sd-BTKA across patients of all BMI groups.

Association of Sports Participation With Osteoarthritis: A Systematic Review and Meta-Analysis

Background:

The association between participating in sport and osteoarthritis is not fully understood.

Purpose:

To investigate the association between osteoarthritis and participating in sports not listed in previous reviews: American football, archery, baseball, bobsleigh, curling, handball, ice hockey, shooting, skeleton, speed skating, and wrestling.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

We searched 4 electronic databases and hand searched recent/in-press editions of relevant journals. The criteria for study selection were case-control studies, cohort studies, nested case-control studies, and randomized trials with a control group that included adults to examine the effect of exposure to any of the included sports on the development of osteoarthritis.

Results:

The search returned 6197 articles after deduplication. Nine studies were included in the final review, covering hip, knee, and ankle osteoarthritis. There were no studies covering archery, baseball, skeleton, speed skating, or curling. The 6 sports included in the review were analyzed as a collective; the results of the meta-analysis indicated that participation in the sports analyzed was associated with an increased risk of developing osteoarthritis of the hip (relative risk [RR] = 1.67 [95% confidence interval (CI), 1.15-2.41]; P = .04), knee (RR = 1.60 [95% CI, 1.23-2.08]; P < .001), and ankle (RR = 7.08 [95% CI, 1.24-40.51]; P = .03) as compared with controls. Meta-analysis suggested a significantly increased likelihood of developing hip osteoarthritis through participating in wrestling (RR = 1.78 [95% CI, 1.20-2.64]; P = .004) and ice hockey (RR = 1.70 [95% CI, 1.27-2.29]; P < .001), while there was no significant difference through participating in handball (RR = 2.50 [95% CI, 0.85-7.36]; P = .10). Likelihood of developing knee osteoarthritis was significantly increased in wrestling (RR = 2.22 [95% CI, 1.59-3.11]) and ice hockey (RR = 1.52 [95% CI, 1.18-1.96]; both P < .002). According to the meta-analysis, shooting did not have a significant effect on the RR of knee osteoarthritis as compared with other sports (RR = 0.43 [95% CI, 0.06-2.99]; P = .39).

Conclusion:

The likelihood of developing hip and knee osteoarthritis was increased for ice hockey and wrestling athletes, and the risk of developing hip osteoarthritis was increased for handball athletes. The study also found that participation in the sports examined, as a collective, resulted in an increased risk of developing hip, knee, and ankle osteoarthritis.

Incidence and risk factors for poor ankle functional recovery, and the development and progression of posttraumatic ankle osteoarthritis after significant ankle ligament injury (SALI): the SALI cohort study protocol

Background

Ankle sprains are one of the most common musculoskeletal injuries, accounting for up to 5% of all Emergency Department visits in the United Kingdom. Ankle injury may be associated with future ankle osteoarthritis. Up to 70% of ankle osteoarthritis cases may be associated with previous ankle injury. There is limited research regarding the association between ankle sprain and ankle osteoarthritis development. The current study aims to phenotype those who suffer significant ankle ligament injuries, identify potential risk factors for ankle injuries and subsequent poor recovery, examine why individuals may develop osteoarthritis, and what factors influence this chance.

Methods

In this multicentre cohort study participants were recruited from nine Emergency Departments and two Urgent Care Centres in the United Kingdom. Participants (aged 18–70 years old) were defined as those who had suffered an isolated acute ankle sprain, which was Ottawa Ankle Rules positive, but negative for a significant ankle fracture on x-ray. Age and sex matched controls were also recruited. The controls were individuals who had not suffered a significant ankle injury, including ankle pain, function affected for more than 7 days, or the ankle caused them to report to an Emergency Department. Data is collected through a series of seven questionnaires (at baseline, 3 months, 1 year, 3 years, 5 years, 10 years, and 15 years later). The questionnaires include four sections (demographic questions; index injury, and injury history questions; functional assessment questions; and quality of life questions) and are designed to collect detailed information about the individual, their injury, potential risk factors for ankle sprains and ankle osteoarthritis, plus their medical history and any medication consumed.

Discussion

The Significant Ankle Ligament Injury (SALI) study aims to add to the limited knowledge regarding which factors can predict ankle sprains, complaints, and osteoarthritis. This is important because despite ankle sprains being regarded as a benign injury that resolves quickly, residual symptoms are not uncommon months and years after the injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04230-8.

Serum fatty acid chain length associates with prevalent symptomatic end-stage osteoarthritis, independent of BMI

Higher body mass index (BMI) is associated with osteoarthritis (OA) in both weight-bearing and non-weight-bearing joints, suggesting a link between OA and poor metabolic health beyond mechanical loading. This risk may be influenced by systemic factors accompanying BMI. Fluctuations in concentrations of metabolites may mark or even contribute to development of OA. This study explores the association of metabolites with radiographic knee/hip OA prevalence and progression. A ¹H-NMR-metabolomics assay was performed on plasma samples of 1564 cases for prevalent OA and 2,125 controls collected from the Rotterdam Study, CHECK, GARP/NORREF and LUMC-arthroplasty cohorts. OA prevalence and 5 to 10 year progression was assessed by means of Kellgren-Lawrence (KL) score and the OARSI-atlas. End-stage knee/hip OA (TJA) was defined as indication for arthroplasty surgery. Controls did not have OA at baseline or follow-up. Principal component analysis of 227 metabolites demonstrated 23 factors, of which 19 remained interpretable after quality-control. Associations of factor scores with OA definitions were investigated with logistic regression. Fatty acids chain length (FALen), which was included in two factors which associated with TJA, was individually associated with both overall OA as well as TJA. Increased Fatty Acid chain Length is associated with OA.

Examining the Association of Knee Pain with Modifiable Cardiometabolic Risk Factors

OBJECTIVE

There is a well-established link between obesity and knee osteoarthritis, and recent research has implicated diabetes as a potential cause of cartilage degeneration. This study uses the National Health and Nutrition Examination Survey (NHANES) database to examine the association between knee pain and various metabolic factors.

METHODS

A retrospective cross-sectional study of the NHANES database from 1999 to 2004 was performed. The main outcome was any knee pain and bilateral knee pain. Main effects of interest were body mass index (BMI), and hemoglobin A1c (HbA1c). We additionally assessed various patient factors including age, race, poverty, gender and smoking status. Multivariable logistic regression models and interaction terms were analyzed.

RESULTS

Data on 12,900 patients was included. In the main adjusted analysis, the modifiable risk factors associated with any knee pain were: overweight (OR 0.91; 95% CI 0.85, 0.97), obesity (OR 1.54; 95% CI 1.42, 1.66), glycemic control (OR 1.20; 95% CI 1.03, 1.38), and current smokers (OR 1.15; 95% CI 1.05, 1.27), all p<0.05. These same factors remain significant for bilateral knee pain. Subgroup analysis showed patients under 65 years old have a 5% increase in risk of any knee pain as their body mass index increases, but patients 65 years and older have a 10% increase in risk.

CONCLUSION

This study confirms the association of knee pain with increased weight, glycemic control, current smoking and age. Most of these risk factors can be modified in patients with knee pain and should be discussed when providing conservative treatment options.

Obesity and its effect on outcomes in same-day bilateral total knee arthroplasty

Background

The niche surgery of same-day bilateral total knee arthroplasty (sd-BTKA) continues to create debate amongst specialists in arthroplasty. To date, there is a significant lack of literature on obese patients undergoing sd-BTKA, and no study has evaluated outcomes of this procedure when compared to non-obese patients. Therefore, this study will perform a retrospective analysis to compare (I) incidence, (II) demographics, and (III) complications of sd-BTKA in non-obese, obese, and morbidly obese patients in the United States from 2009 to 2016.

Methods

The National Inpatient Sample (NIS) database was queried for all individuals that underwent sd-BTKA from 2009 to 2016. This returned 184,844 non-obese patients, 39,901 obese patients, and 20,394 morbidly obese patients. Analyzed variables included mean age, mean length of stay (LOS), race, payer, age-adjusted Charlson Comorbidity Index score, discharge disposition, hospital charges, hospital costs, and complications. Chi-square analyses and analyses of variance were utilized to assess categorical and continuous variables, respectively.

Results

Non-obese patients most commonly underwent sd-BTKA over the course of the study. As weight status increased, mean age decreased and the proportion of females, LOS, hospital charges and costs, and proportion of discharges to skilled nursing facilities increased. Regression analysis demonstrated obese and morbidly obese cohorts were at an overall increased odds for experiencing complications. Specifically, obese patients were at increased risk for pulmonary emboli, periprosthetic joint infections, and respiratory failures, while morbidly obese patients are at increased risk for pulmonary emboli, respiratory failures, and urinary tract infections.

Conclusions

Surgeons should thoroughly evaluate the risks and benefits of performing sd-BTKA on obese and morbidly obese patients, as both confer higher overall complication rates and increased length of stay. More research is necessary to characterize the cost analysis of this procedure, as health care models continue to transition to more cost-effective procedures.

Ex vivo physiological compression of human osteoarthritis cartilage modulates cellular and matrix components

Mechanical stimulation appears to play a key role in cartilage homeostasis maintenance, but it can also contribute to osteoarthritis (OA) pathogenesis. Accumulating evidence suggests that cartilage loading in the physiological range contributes to tissue integrity maintenance, whereas excessive or reduced loading have catabolic effects. However, how mechanical stimuli can regulate joint homeostasis is still not completely elucidated and few data are available on human cartilage. We aimed at investigating human OA cartilage response to ex vivo loading at physiological intensity. Cartilage explants from ten OA patients were subjected to ex vivo controlled compression, then recovered and used for gene and protein expression analysis of cartilage homeostasis markers. Compressed samples were compared to uncompressed ones in presence or without interleukin 1β (IL-1β) or interleukin 4 (IL-4). Cartilage explants compressed in combination with IL-4 treatment showed the best histological scores. Mechanical stimulation was able to significantly modify the expression of collagen type II (collagen 2), aggrecan, SOX9 transcription factor, cartilage oligomeric matrix protein (COMP), collagen degradation marker C2C and vascular endothelial growth factor (VEGF). Conversely, ADAMTS4 metallopeptidase, interleukin 4 receptor alpha (IL4Rα), chondroitin sulfate 846 epitope (CS846), procollagen type 2 C-propeptide (CPII) and glycosaminoglycans (GAG) appeared not modulated. Our data suggest that physiological compression of OA human cartilage modulates the inflammatory milieu by differently affecting the expression of components and homeostasis regulators of the cartilage extracellular matrix.

A randomised pilot equivalence trial to evaluate diamagnetically enhanced transdermal delivery of key ground substance components in comparison to an established transdermal non-steroidal anti-inflammatory formulation in males with prior knee injury

Objective

This pilot study assessed the efficacy of a knee guard device, which used magnetophoresis to transdermally deliver Glucosamine, Chondroitin and Hyaluronic Acid in a cohort of individuals with prior knee injury. The aim was to determine if the change in physical function and pain with the knee guard device was equivalent to the change produced by an established topical NSAID formulation containing diclofenac sodium 1%.

Methods

A randomized, controlled, equivalence trial evaluated outcomes following treatment with the knee guard device or NSAID formulation. The study recruited 114 male participants (aged 40–55 years). Participants were randomly allocated to wear the knee guard device or to use a NSAID gel daily for two weeks. The primary outcomes were the knee injury osteoarthritis function score (KOOS-F) and an aggregated function score (AFS). The lower extremity functional scale (LEFS), pain numerical rating scale (PNRS), global rating of change (GROC) and other KOOS scores were also evaluated.

Results

Multiple linear regression analyses indicated that there were no significant differences between the interventions for changes in the primary outcomes of AFS and KOOS_F. The 95% confidence interval (-2.89 to 5.15) of the estimated treatment difference for KOOS-F was within the lower (-5.61) and upper (5.61) bounds of the 7% equivalence margin for that measure, The mean value for the AFS was within, but the 95% CI (-3.11 to 7.37) exceeded the 7% equivalence margin (-2.97 to 2.97) for that measure. There was a significant difference in PNRS, which favored the knee guard device.

Conclusion

The knee guard device demonstrated equivalence for the KOOS-F measure but not the AFS measure of function over the two week trial period when compared to a widely available NSAID gel that has been shown to be superior to placebo. The knee guard produced a greater reduction in pain report (p = 0.002) than the NSAID gel. Users of the knee guard device experienced more skin irritation than participants using the NSAID gel. Further research is required to fully evaluate the therapeutic potential of this innovative treatment approach.

US National Health and Nutrition Examination Survey Arthritis Initiatives, Methodologies and Data

The US National Health and Nutrition Examination Survey (NHANES) has collected population-based, nationally representative examination, laboratory, and radiographic data for arthritis and musculoskeletal diseases for more than 50 years. The resulting body of data and publications are substantial, yet much data remain unpublished. This review provides a basic understanding of the design and capabilities of the NHANES survey, reviewing the major accomplishments in the area of arthritis and musculoskeletal diseases. Currently available US National Health and Nutrition Examination Survey arthritis-related datasets are identified. Guidelines for using these data, and opportunities for data analysis and designing future studies are presented.

Prevalence of knee osteoarthritis in former athletes: a systematic review with meta-analysis

BACKGROUND

Prevalence of knee osteoarthritis in former athletes is still unclear.

OBJECTIVE

To investigate prevalence of knee osteoarthritis in former athletes. Moreover, the secondary aim was to investigate whether poor methodological quality of included studies, different diagnosis criteria for knee osteoarthritis, different sports modality or sex impact on overall estimated prevalence of knee osteoarthritis in former athletes.

METHODS

Searches on MEDLINE, EMBASE, AMED, SPORTDiscus and CINAHL from the earliest record to February 2018 and hand-searching identified studies investigating prevalence of knee osteoarthritis in former athletes. Meta-analysis was conducted and the GRADE system summarized strength of the current recommendations. Sensitivity analyses investigated whether methodological quality, diagnostic criteria, type of sports or sex impacted on the overall estimated prevalence in former athletes. This review was registered at PROSPERO (CRD42016050903).

RESULTS

Fifteen studies were included and pooling of 3100 participants estimated overall prevalence of knee osteoarthritis in former athletes of 30.0% (95% CI: 20.0 to 40.0%). The strength of the current recommendations was low-quality. Sensitivity analyses suggested that different diagnostic criteria for knee osteoarthritis and type of sports may impact on the overall estimated prevalence.

CONCLUSIONS

Prevalence of knee osteoarthritis in former athletes was 30.0%. Researchers, clinicians and policymakers should be careful about potential prevalence differences among type of sports and diagnostic criteria. Current low-quality evidence shows that future high-quality studies are likely to impact on the estimated prevalence.

Factors that determine kinematic coupling behavior of calcaneal pronation/supination and shank rotation during weight bearing: ananalysis based on foot bone alignment using radiographic images

[Purpose] This study aimed to identify factors that determine the kinematic coupling behavior of calcaneal pronation/supination and shank rotation in a standing position. [Participants and Methods] Study participants included 15 healthy adults (30 legs). Kinematic coupling behavior was quantified as the linear regression coefficient (kinetic chain ratio [KCR]) of the angle of shank rotation against the angle of calcaneal pronation-to-supination measured using a 3-dimensional motion analysis system during pronation and supination of both feet while standing. The relationship between the KCR and the foot bone alignment was also analyzed using 35 parameters that were evaluated based on plain radiography. [Results] Greater the height of the medial longitudinal arch, and greater the backward tilt of the long axis of the talus and the backward tilt of the talar articular surface of the calcaneus, larger the KCR. This alignment differed between the genders. [Conclusion] This study suggested that the KCR increases as the subtalar joint axis approaches the long axis of the shank secondary to the lifting of the medial longitudinal arch of the foot and decreases as the subtalar joint axis approaches the long axis of the foot secondary to the lowering of the medial longitudinal arch of the foot.

Long-term results of posterior cruciate ligament tear with or without reconstruction: A nationwide, population-based cohort study

BACKGROUND

There is increasing interest in the long-term outcomes of patients with posterior cruciate ligament (PCL) tears following conservative treatment or reconstruction. However, limited information is available regarding these results because of the relative rarity of cases and lack of long-term follow-up.

PURPOSE

The goals of this study are to (1) compare the occurrence of secondary meniscal tears, osteoarthritis (OA) or subsequent total knee replacement (TKR) in patients with or without PCL injury, and (2) evaluate the potential protective effect of PCL reconstruction against long-term sequela in patients with PCL deficiency.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective cohort study evaluated the long-term results of PCL deficiency with or without reconstruction in Taiwan based on data from the National Health Insurance Research Database (NHIRD) from 2000 to 2015. The cumulative incidence rates of meniscus tear, OA and TKR were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

A total of 4,169 patients diagnosed with PCL tear from 2000 to 2015 in Taiwan were included in the study. There was a higher cumulative incidence of meniscus tear (1.13%), OA (2.71%) and subsequent TKR (0.91%) among patients with a PCL tear than among patients without one (0.22%, 1.90%, 0.62%; all p < 0.05). PCL reconstruction patients had a decreased cumulative incidence of meniscus tear (0.41%), OA (2.30%) and subsequent TKR (0.48%) compared with non-reconstructed patients (2.44%, 3.46%, 1.69%; all p < 0.05). After adjusting for covariates, PCL-injured patients who underwent reconstruction within one year after PCL injury showed a significantly lower risk of subsequent sequelae than those who never underwent reconstruction (within 1 month: adjusted HR = 0.390, 95% CI = 0.284-0.535; 1 month to 1 year: adjusted HR = 0.546, 95% CI = 0.398-0.748).

CONCLUSIONS

Patients with PCL tears have a significantly higher risk of meniscus tear, OA and subsequent TKR than patients without PCL tears. PCL reconstruction could decrease the cumulative incidence of these outcomes. The results suggest that PCL-injured patients should undergo reconstruction as early as possible (within one year) to reduce the risk of further degeneration.

Mortality and Implant Survival With Simultaneous and Staged Bilateral Total Knee Arthroplasty Experience From the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

Total knee arthroplasty (TKA) is an effective procedure for relieving pain and restoring function in osteoarthritis, with a significant proportion of patients having severe disease bilaterally. However, although there are differences in patient selection criteria for bilateral procedures, there is no consensus regarding the optimal timing for bilateral TKA. The aim of this study was to compare rates and causes of revision and 30-day mortality between simultaneous and staged bilateral TKA using data from the Australian Orthopaedic Association National Joint Replacement Registry.

METHODS

Data for over 36,000 bilateral TKAs were collected from September 1999 to December 2015. Rates and causes of revision and 30-day mortality rates were obtained for simultaneous bilateral and staged procedures with intervals of 1 day-6 weeks, 6 weeks-3 months, and 3-6 months. Yearly cumulative percent revision or cumulative percent survival with 95% confidence intervals calculated using the Kaplan-Meier method and adjusted hazard ratios were used for comparisons.

RESULTS

There was no significant difference between revision rates or reasons for revision between staged bilateral and simultaneous TKA (hazard ratio 1.09 [95% confidence interval {CI} 0.85-1.40; P = .511] for 1 day-6 weeks, 0.93 [95% CI 0.77-1.14; P = .494] for 6 weeks-3 months, and 1.10 [95% CI 0.98-1.23; P = .115] for 3-6 months). The most common reasons for revision were loosening/lysis and infection. The 30-day mortality rates were lower in the 6 weeks-3 months group than simultaneous bilaterals (P = .007).

CONCLUSION

This study demonstrates that simultaneous and staged bilateral TKA have similar rates of revision over the medium term but that 30-day mortality is reduced in the 6 weeks-3 months group.

Staggered Rather Than Staged or Simultaneous Surgical Strategy May Reduce the Risk of Acute Kidney Injury in Patients Undergoing Bilateral TKA

BACKGROUND

The strategy for bilateral total knee arthroplasty (TKA) depends on the timing of surgery for each knee. The purpose of this study was to determine whether the type of surgical strategy for bilateral TKA (staggered, staged, or simultaneous) influences the incidence of acute kidney injury (AKI) and related complications.

METHODS

Enrolled patients from a single tertiary teaching hospital were divided into 3 groups according to the surgical strategy for bilateral TKA: staggered (≤7 days between the first and second procedure; n = 368), staged (8 days to 1 year between the first and second procedure; n = 265), or simultaneous (n = 820). The incidence of AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria was assessed. The rates of major postoperative complications, major adverse cardiovascular and cerebral events, intensive care unit (ICU) admissions, and mortality were also evaluated. To reduce the influence of possible confounding factors, inverse probability of treatment weighting based on propensity-score analysis was used.

RESULTS

The primary outcome was the incidence of AKI according to surgical strategy. The staggered group had a lower rate of AKI compared with the other 2 groups (p < 0.001): 2.4% (9 of 368 patients), 6.0% (16 of 265), and 11.2% (92 of 820) in the staggered, staged, and simultaneous groups, respectively.

CONCLUSIONS

The type of bilateral TKA strategy was an independent risk factor for the development of AKI. The assessment of additional risk factors for the development of AKI is essential before deciding on surgical strategy.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Females, younger patients and patients with high BMI have the highest pre-operative knee awareness measured using the Forgotten Joint Score

PURPOSE

The Forgotten Joint Score (FJS) is a novel measurement for patients' awareness of their knee in daily life. By identifying factors that could explain pre-operative FJS levels, the clinician could better prioritize and single out patients who would benefit most from TKA. The aim of this study was to identify possible factors that may explain the variance of pre-operative FJS levels and evaluate the relationship between pre-operative FJS and pre-operative Oxford Knee Score (OKS).

METHODS

Four-hundred and six individual knees undergoing primary TKA between 2014 and 2016 were included in the study. Age, gender, body mass index (BMI), pre-operative FJS and pre-operative OKS were obtained maximum 2 weeks prior to surgery. Kellgren-Lawrence (K-L) grade, alignment and joint space width (JSW) were evaluated on pre-operative radiographs.

RESULTS

Mean FJS was 21.1 ± 15.6. Females, younger patients and patients with high BMI had significantly the worst pre-operative FJS (p < 0.005). Females scored 6.5 FJS points lower than males. A 0.2-point increase in FJS for every added year indicated improvement in knee awareness with age. A 0.4-point decrease in FJS points for every added BMI point indicated worse knee awareness with higher BMI. There was a strong positive correlation between pre-operative FJS and pre-operative OKS according to the Spearman's rank order test (p < 0.005).

CONCLUSIONS

Females, younger patients and patients with high BMI had significantly the worst pre-operative joint awareness. FJS had a strong positive correlation to OKS in pre-operative patients for primary TKA. This information can be used for improved patient selection; clinically continuous low FJS despite weight loss and/or the passing of time may be indication for TKA.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Risk factors for progression of radiographic knee osteoarthritis in elderly community residents in Korea

BACKGROUND

Knee osteoarthritis (OA) is the most common form of arthritis affecting the elderly. Understanding the risk factors for knee OA has been derived from cross sectional studies. There have been few longitudinal studies of risk factors for knee OA among Asian populations. The purpose of this study was to evaluate the risk factors for knee OA in elderly Korean community residents.

METHODS

This prospective, population-based study was conducted on residents over 50 years of age in Chuncheon who participated in the Hallym Aging Study. Standardized weight-bearing semi-flexed knee anteroposterior radiographs were obtained in 2007 and in 2010. Of 504 participants at baseline, 322 participants (male: female = 150:172) underwent follow-up knee radiographs. Radiographic knee OA was defined as Kellgren/Lawrence (K-L) grade of ≥ 2. Risk factors assessed at baseline were tested for their association with incidence, progression, and worsening of radiographic knee OA by logistic regression analysis.

RESULTS

The median age of these participants at follow-up was 71 years (interquartile range 66-75 years). Incident OA was observed in 33 (10.2%) and progression of OA (defined as an increase of Kellgren-Lawrence (K-L) grade at follow-up, from grades 2 or 3 at baseline) in 43 (13.55%) participants. In multivariate logistic regression analysis, only females were significantly associated with the progression of radiographic knee OA (odds ratio [OR] = 4.41, 95% confidence interval [CI] 1.32-14.77).

CONCLUSIONS

In this 3-year longitudinal study, the yearly incidence and progression of knee OA was higher than those previously reported in Western populations.

Baseline varus deformity is associated with increased joint loading and pain of non-operated knee two years after unilateral total knee arthroplasty

BACKGROUND

The goals of this study were (1) to document the gait pattern of patients with unilateral knee osteoarthritis (OA), (2) to determine the knee adduction moment (KAM) changes in the non-operated knee, and (3) to identify the predictors of change in KAM in the non-operated knee.

METHODS

The study recruited 23 patients with advanced unilateral knee OA. The preoperative Kellgren-Lawrence (KL) grade of the non-operated knee was one or two; non-operated knee pain, rated using a numeric rating scale (NRS), was less than three out of 10 points. We used a commercial gait analysis system to evaluate kinetics and kinematics. Radiological and gait measurements at the two-year follow-up were compared with baseline data.

RESULTS

The preoperative asymmetrical gait cycle characterized by elongation of the stance phase of the non-operated knee became symmetrical after TKA. The average KAM of the non-operated knee increased (P=0.010) and it was best predicted by the baseline mechanical axis of the non-operated knee. If the baseline mechanical axis was varus four degrees or above (varus group), the average KAM increased by 0.64 (% body weight×height, P=0.015), while for varus less than four degrees (non-varus group), KAM was unchanged. The KL grade was increased in the varus group (P=0.020) but it was unchanged in the non-varus group. Average pain NRS score was also higher (P=0.044) in the varus group.

CONCLUSIONS

Close follow-up is necessary for patients with a baseline varus deformity of the non-operated knee because of the higher possibility of developing pain, subsequent arthritis and increased joint loading of the non-operated knee.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Advancing osteochondral tissue engineering: bone morphogenetic protein, transforming growth factor, and fibroblast growth factor signaling drive ordered differentiation of periosteal cells resulting in stable cartilage and bone formation in vivo

Background

Chondrogenic mesenchymal stem cells (MSCs) have not yet been used to address the clinical demands of large osteochondral joint surface defects. In this study, self-assembling tissue intermediates (TIs) derived from human periosteum-derived stem/progenitor cells (hPDCs) were generated and validated for stable cartilage formation in vivo using two different animal models.

Methods

hPDCs were aggregated and cultured in the presence of a novel growth factor (GF) cocktail comprising of transforming growth factor (TGF)-β1, bone morphogenetic protein (BMP)2, growth differentiation factor (GDF)5, BMP6, and fibroblast growth factor (FGF)2. Quantitative polymerase chain reaction (PCR) and immunohistochemistry were used to study in vitro differentiation. Aggregates were then implanted ectopically in nude mice and orthotopically in critical-size osteochondral defects in nude rats and evaluated by microcomputed tomography (µCT) and immunohistochemistry.

Results

Gene expression analysis after 28 days of in vitro culture revealed the expression of early and late chondrogenic markers and a significant upregulation of NOGGIN as compared to human articular chondrocytes (hACs). Histological examination revealed a bilayered structure comprising of chondrocytes at different stages of maturity. Ectopically, TIs generated both bone and mineralized cartilage at 8 weeks after implantation. Osteochondral defects treated with TIs displayed glycosaminoglycan (GAG) production, type-II collagen, and lubricin expression. Immunostaining for human nuclei protein suggested that hPDCs contributed to both subchondral bone and articular cartilage repair.

Conclusion

Our data indicate that in vitro derived osteochondral-like tissues can be generated from hPDCs, which are capable of producing bone and cartilage ectopically and behave orthotopically as osteochondral units.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0787-3) contains supplementary material, which is available to authorized users.

Cost Analysis, Complications, and Discharge Disposition Associated With Simultaneous vs Staged Bilateral Total Knee Arthroplasty

BACKGROUND

Simultaneous vs staged bilateral total knee arthroplasty (BTKA) has long been debated. The primary objective of this study was to compare actual hospital costs and complication rates in patients undergoing simultaneous BTKA (simBTKA) and staged BTKA (staBTKA) at a single institution.

METHODS

A total joint arthroplasty database from a single hospital was used to identify all patients who underwent primary BTKA from 2013 to 2016 and divided into simultaneous and staged groups. StaBTKA patients were included if both procedures were performed within 1 year by the same surgeon. The combined total hospital cost of both procedures was used, and inpatient rehabilitation (IPR) costs were added for all patients discharged to IPR.

RESULTS

There were 225 simBTKA and 337 staBTKA patients. SimBTKA patients were younger (61 ± 8 vs 66 ± 8 years, P < .001), had lower body mass index (31.3 ± 5.9 vs 34.0 ± 7.2, P < .001), were more predominately male (48% vs 38%, P = .029), and more likely to require IPR as compared with staBTKA patients. There was no difference in total hospital cost for simBTKA as compared with staBTKA ($24,596 ± $5652 vs $24,915 ± $5756, P = .586). Complications were more prevalent in the simBTKA group, including venous thromboembolism (5.4% vs 1.4%, P = .006) and blood transfusions (15.8% vs 6.2%, P < .001).

CONCLUSION

There were higher complication rates with no significant cost savings in actual hospital costs associated with simBTKA, when accounting for the cost of IPR, as compared with staBTKA. The total cost analysis of simBTKA vs staBTKA, using actual cost data, merits further evaluation.

Method for Estimating Three-Dimensional Knee Rotations Using Two Inertial Measurement Units: Validation with a Coordinate Measurement Machine

Three-dimensional rotations across the human knee serve as important markers of knee health and performance in multiple contexts including human mobility, worker safety and health, athletic performance, and warfighter performance. While knee rotations can be estimated using optical motion capture, that method is largely limited to the laboratory and small capture volumes. These limitations may be overcome by deploying wearable inertial measurement units (IMUs). The objective of this study is to present a new IMU-based method for estimating 3D knee rotations and to benchmark the accuracy of the results using an instrumented mechanical linkage. The method employs data from shank- and thigh-mounted IMUs and a vector constraint for the medial-lateral axis of the knee during periods when the knee joint functions predominantly as a hinge. The method is carefully validated using data from high precision optical encoders in a mechanism that replicates 3D knee rotations spanning (1) pure flexion/extension, (2) pure internal/external rotation, (3) pure abduction/adduction, and (4) combinations of all three rotations. Regardless of the movement type, the IMU-derived estimates of 3D knee rotations replicate the truth data with high confidence (RMS error < 4 ° and correlation coefficient r ≥ 0.94 ).

Knee osteoarthritis has doubled in prevalence since the mid-20th century

Knee osteoarthritis (OA) is believed to be highly prevalent today because of recent increases in life expectancy and body mass index (BMI), but this assumption has not been tested using long-term historical or evolutionary data. We analyzed long-term trends in knee OA prevalence in the United States using cadaver-derived skeletons of people aged ≥50 y whose BMI at death was documented and who lived during the early industrial era (1800s to early 1900s; n = 1,581) and the modern postindustrial era (late 1900s to early 2000s; n = 819). Knee OA among individuals estimated to be ≥50 y old was also assessed in archeologically derived skeletons of prehistoric hunter-gatherers and early farmers (6000-300 B.P.; n = 176). OA was diagnosed based on the presence of eburnation (polish from bone-on-bone contact). Overall, knee OA prevalence was found to be 16% among the postindustrial sample but only 6% and 8% among the early industrial and prehistoric samples, respectively. After controlling for age, BMI, and other variables, knee OA prevalence was 2.1-fold higher (95% confidence interval, 1.5-3.1) in the postindustrial sample than in the early industrial sample. Our results indicate that increases in longevity and BMI are insufficient to explain the approximate doubling of knee OA prevalence that has occurred in the United States since the mid-20th century. Knee OA is thus more preventable than is commonly assumed, but prevention will require research on additional independent risk factors that either arose or have become amplified in the postindustrial era.

Total Knee Arthroplasty for Osteoarthritis in Patients Less Than Fifty-Five Years of Age: A Systematic Review

BACKGROUND

The proportion of younger patients undergoing total knee arthroplasty (TKA) is increasing and predictions state that the <55 age group will be the fastest growing group by 2030. We aim to collate data across studies to assess functional outcomes following TKA in patients <55 years of age using a systematic review.

METHODS

The search identified 980 studies for title and abstract review. Forty-three full texts were then assessed. Thirteen studies underwent quality assessment and data extraction. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed throughout. Outcomes extracted included pre-operative and post-operative functional scores, range of motion, and patient satisfaction. Clinical complications and survival were also recorded.

RESULTS

Across 13 studies we were able to demonstrate 54-point improvement in clinical Knee Society Score and a 46-point improvement on functional Knee Society Score. A 2.9° improvement in range of motion was found at final follow-up. Satisfaction rate was 85.5%. Cumulative percentage all-cause revision rate was 5.4% across 1283 TKAs at a mean 10.8 years of follow-up. Ten-year survival, for aseptic loosening alone, was 98.2%.

CONCLUSION

TKA is an excellent treatment option for the young osteoarthritic knee with a >50% improvement in functional knee scores. Satisfaction is high and the revision rate remains 0.5% per year.

Association of anterior cruciate ligament injury with knee osteoarthritis and total knee replacement: A retrospective cohort study from the Taiwan National Health Insurance Database

Objective

This study aimed to support the potential protective role of anterior cruciate ligament (ACL) reconstruction against the development of osteoarthritis (OA).

Methods

In this retrospective cohort study, the long-term results of ACL reconstruction in Taiwan were evaluated based on data from the National Health Insurance Research Database (NHIRD). In total, 8,769 eligible cases were included from 11,921 ACL-injured patients. The cumulative incidence rates of OA and total knee replacement (TKR) were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of OA.

Results

There was a lower cumulative incidence of OA among ACL-reconstructed patients (271, 33.1%) than among non-reconstructed patients (1,874, 40.3%; p < 0.001). Patients who underwent ACL reconstruction had a lower cumulative incidence of TKR during the follow-up period (0.6%) than the non-reconstructed patients (4.6%, p < 0.001). After adjusting for covariates, ACL-injured patients who underwent reconstruction within one month after ACL injury showed a significantly lower risk of OA than those who never underwent reconstruction (adjusted HR = 0.83, 95% CI = 0.69–0.99).

Conclusions

These results indicate that ACL reconstruction might not provide complete protection from OA development after traumatic knee injury but does yield a lower cumulative incidence of OA development and TKR. Moreover, based on the present study, ACL-injured patients should undergo reconstruction as early as possible (within one month) to lower the risk of OA.

Primary Cartilage Lesions of the Knee Joint in Young Male Adults. Overweight as a Predisposing Factor. An Arthroscopic Study

Background and Aims:

This study was undertaken to evaluate the relationship between overweight and severity of arthroscopically confirmed primary cartilage lesions of the knee.

Material and Methods:

The hospital records of 88 young male adults (98 knees), who underwent arthroscopy of the knee and were diagnosed of primary cartilage lesion during 1997–98, were reviewed. The depth of the lesions was graded according to Beguin and Locker classification.

Results:

73.5 % of the lesions were patellar and 12.0 % in the medial condyle of the femur. 74.5 % of the patients had superficial (grade I—II) and 25.5 % deep (grade III—IV) lesions. Patients with deep lesions had a significantly higher body mass index (BMI 25.3 vs. 22.9, p < 0.001) and they were older (20.8 vs. 19.7 years, p = 0.023) than other patients. Similarly, patients with overweight (BMI ≥ 25.0) had significantly more often deep lesions than other patients (50 % vs. 10.4 %, p < 0.001).

Conclusions:

These results suggest, that overweight may predispose young patients to more severe cartilage lesions independent of other etiologic factors, and support the hypothesis of the cumulative effect of overweight on cartilage injuries during early adult life.

Simultaneous Bilateral Versus Unilateral Total Knee Arthroplasty: A Comparison of 30-Day Readmission Rates and Major Complications

We queried the National Surgical Quality Improvement Program to compare the rate of 30-day readmissions and major complications between simultaneous bilateral and unilateral total knee arthroplasty (TKA). We identified 1771 patients who underwent simultaneous (same-day) bilateral TKA and matched them to a control group of 6790 patients who underwent unilateral TKA. The simultaneous bilateral TKA patients had longer surgery, were more commonly performed under general anesthesia, had a higher rate of postoperative transfusion, and a greater proportion of patients discharged to rehabilitation facilities. Simultaneous bilateral TKA has a low incidence of major complications and was not associated with more readmissions as compared to unilateral TKA (3.6% versus 3.5% respectively). Nonetheless, the odds of major complications was slightly higher following simultaneous bilateral TKA (OR=1.58).

Joint distraction attenuates osteoarthritis by reducing secondary inflammation, cartilage degeneration and subchondral bone aberrant change

OBJECTIVE

Osteoarthritis (OA) is a progressive joint disorder. To date, there is not effective medical therapy. Joint distraction has given us hope for slowing down the OA progression. In this study, we investigated the benefits of joint distraction in OA rat model and the probable underlying mechanisms.

METHODS

OA was induced in the right knee joint of rats through anterior cruciate ligament transaction (ACLT) plus medial meniscus resection. The animals were randomized into three groups: two groups were treated with an external fixator for a subsequent 3 weeks, one with and one without joint distraction; and one group without external fixator as OA control. Serum interleukin-1β level was evaluated by ELISA; cartilage quality was assessed by histology examinations (gross appearance, Safranin-O/Fast green stain) and immunohistochemistry examinations (MMP13, Col X); subchondral bone aberrant changes was analyzed by micro-CT and immunohistochemistry (Nestin, Osterix) examinations.

RESULTS

Characters of OA were present in the OA group, contrary to in general less severe damage after distraction treatment: firstly, IL-1β level was significantly decreased; secondly, cartilage degeneration was attenuated with lower histologic damage scores and the lower percentage of MMP13 or Col X positive chondrocytes; finally, subchondral bone abnormal change was attenuated, with reduced bone mineral density (BMD) and bone volume/total tissue volume (BV/TV) and the number of Nestin or Osterix positive cells in the subchondral bone.

CONCLUSION

In the present study, we demonstrated that joint distraction reduced the level of secondary inflammation, cartilage degeneration and subchondral bone aberrant change, joint distraction may be a strategy for slowing OA progression.

Web-Based Study of Risk Factors for Pain Exacerbation in Osteoarthritis of the Knee (SPARK-Web): Design and Rationale

Background

Knee osteoarthritis (OA) is the most frequent cause of limited mobility and diminished quality of life. Pain is the main symptom that drives individuals with knee OA to seek medical care and a recognized antecedent to disability and eventually joint replacement. Many persons with symptomatic knee OA experience recurrent pain exacerbations. Knowledge and clarification of risk factors for pain exacerbation may allow those affected to minimize reoccurrence of these episodes.

Objective

The aim of this study is to use a Web-based case-crossover design to identify risk factors for knee pain exacerbations in persons with symptomatic knee OA.

Methods

Web-based case-crossover design is used to study persons with symptomatic knee OA. Participants with knee pain and radiographic knee OA will be recruited and followed for 90 days. Participants will complete an online questionnaire at the baseline and every 10 days thereafter (totaling up to 10 control-period questionnaires); participants will also be asked to report online when they experience an episode of increased knee pain. Pain exacerbation will be defined as an increase in knee pain severity of two points from baseline on a numeric rating scale (NRS 0-10). Physical activity, footwear, knee injury, medication use, climate, psychological factors, and their possible interactions will be assessed as potential triggers for pain exacerbation using conditional logistic regression models.

Results

This project has been funded by the National Health and Medical Research Council (NHMRC). The enrollment for the study has started. So far, 343 participants have been enrolled. The study is expected to be finished in October 2015.

Conclusions

This study will identify risk factors for pain exacerbations in knee OA. The identification and possible modification/elimination of such risk factors will help to prevent the reoccurrence of pain exacerbation episodes and therefore improve knee OA management.

Association of Meniscal Status, Lower Extremity Alignment, and Body Mass Index With Chondrosis at Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND

Knees undergoing revision anterior cruciate ligament reconstruction (rACLR) have a high prevalence of articular cartilage lesions.

HYPOTHESIS

The prevalence of chondrosis at the time of rACLR is associated with meniscal status and lower extremity alignment.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Data from the prospective Multicenter ACL Revision Study (MARS) cohort were reviewed to identify patients with preoperative lower extremity alignment films. Lower extremity alignment was defined by the weightbearing line (WBL) as a percentage of the tibial plateau width, while the chondral and meniscal status of each weightbearing compartment was recorded at the time of surgery. Multivariable proportional odds models were constructed and adjusted for relevant factors to examine which risk factors were independently associated with the degree of medial and lateral compartment chondrosis.

RESULTS

The cohort included 246 patients with lower extremity alignment films at the time of rACLR. Mean (±SD) patient age was 26.9 ± 9.5 years and body mass index (BMI) was 26.4 ± 4.6. The medial compartment had more chondrosis (grade 2/3, 42%; grade 4, 6.5%) than did the lateral compartment (grade 2/3, 26%; grade 4, 6.5%). Disruption of the meniscus was noted in 35% of patients on the medial side and 16% in the lateral side. The mean WBL was 0.43 ± 0.13. Medial compartment chondrosis was associated with BMI (P = .025), alignment (P = .002), and medial meniscal status (P = .001). None of the knees with the WBL lateral to 0.625 had grade 4 chondrosis in the medial compartment. Lateral compartment chondrosis was significantly associated with age (P = .013) and lateral meniscal status (P < .001). Subjects with "intact" menisci were found to decrease their odds of having chondrosis by 64% to 84%.

CONCLUSION

The status of articular cartilage in the tibiofemoral compartments at the time of rACLR is related to meniscal status. Lower extremity alignment and BMI are associated with medial compartment chondrosis.

Knee pain, knee injury, knee osteoarthritis & work

Symptomatic knee osteoarthritis (OA) can be viewed as the end result of a molecular cascade which ensues after certain triggers occur and ultimately results in irreversible damage to the articular cartilage. The clinical phenotype that knee OA can produce is variable and often difficult to accurately predict. This is further complicated by the often poor relationship between radiographic OA and knee pain. As a consequence, it can be difficult to compare studies that use different definitions of OA. However, the literature suggests that while there are multiple causes of knee OA, two have attracted particular attention over recent years; occupation related knee OA and OA subsequent to previous knee injury. The evidence of a relationship, and the strength of this association, is discussed in this chapter.

Adipokines as potential prognostic biomarkers in patients with acute knee injury

This review considers adipokines as predictive biomarkers for early onset post-traumatic knee osteoarthritis (KOA). Serum concentrations of leptin and resistin can predict radiographic changes and are elevated in early KOA, with higher leptin concentrations independently associated with more severe knee changes. Plasma concentrations of resistin are chronically elevated after injury. Leptin, resistin, chemerin and vistfatin induce catabolic enzymes associated with cartilage degeneration. Available literature on adipokines in post-traumatic KOA pathogenesis suggests that they could contribute to risk prediction of early onset post-traumatic KOA. Further research is needed to further understand the association between adipokines, synovitis and long-term outcomes in this population.

Early and late-term results of arthroscopic surgery on patients with gonarthrosis

OBJECTIVE

To provide guidance in the selection of the appropriate patient for arthroscopic debridement.

MATERIALS AND METHODS

Ninety patients who were diagnosed with gonarthrosis according to modified American College of Rheumatology (ACR) criteria and who underwent arthroscopic debridement and meniscectomy were evaluated. Functional assessment of patients was made based on preoperative as well as 1 month and 1 year postoperative results of the Lysholm Knee Score and the Visual Analog Scale (VAS). One year postoperatively, the Tapper-Hoover Scoring System was used to calculate long-term results. Analyses were conducted using SPSS 18 software. For this study ethics committee approval was received from the ethics committee of Ataturk University Medical Studies Department Head on 08.10.2010 at the 6th meeting with regards to the document written on 16.06.2010 with number 998.

RESULTS

Differences between preoperative and 1-month and 1-year postoperative values in the Western Otorino and McMaster Universities Osteoarthrosis (WOMAC) Index, Lysholm and VAS were found to be statistically significant (p<0.001) (Table 1). According to Tapper-Hoover results, 82.8% of patients benefited from arthroscopic debridement in the long term (Table 2). Among body mass index (BMI) groups, the WOMAC, Lysholm and VAS values of obese patients were worse than those of normal weight and underweight patients, and the difference was statistically significant (p<0.005). Late-term results of patients younger than 55 were superior to those over 55.

CONCLUSION

In the treatment of patients with gonarthrosis, arthroscopic debridement is a good option. Patients who have a low BMI and are younger than 55 years old experience more benefit from arthroscopic debridement.

Is loss in femorotibial cartilage thickness related to severity of contra-lateral radiographic knee osteoarthritis?--longitudinal data from the Osteoarthritis Initiative

OBJECTIVE

Anti-catabolic disease modifying drugs (DMOADs) aim to reduce cartilage loss in knee osteoarthritis (KOA). Testing such drugs in clinical trials requires sufficient rates of loss in the study participants to occur, preferably at a mild disease stage where cartilage can be preserved. Here we analyze a "progression" model in mild radiographic KOA (RKOA), based on contra-lateral radiographic status.

METHODS

We studied 837 participants (62.4 ± 9 yrs; 30 ± 4.9 kg/m²; 61.8% women) from the Osteoarthritis Initiative (OAI) with mild to moderate RKOA (Kellgren Lawrence grade [KLG] 2-3) and with/without Osteoarthritis Research Society International (OARSI) atlas radiographic joint space narrowing (JSN). These had quantitative measurements of subregional femorotibial cartilage thickness from magnetic resonance imaging (MRI) at baseline and 1-year follow-up. They were stratified by contra-lateral knee status: no (KLG 0/1), definite (KLG2) and moderate RKOA (KLG 3/4).

RESULTS

KLG2 knees with JSN and moderate contra-lateral RKOA had (P = 0.008) greater maximum subregional cartilage loss -220 μm [95% confidence interval (CI) -255, -184 μm] than those without contra-lateral RKOA -164 μm [-187, -140 μm]. Their rate of subregional cartilage loss was similar and not significantly different (P = 0.61) to that in KLG 3 knees without contra-lateral RKOA (-232 μm; [-266; -198 μm]). The effect of contra-lateral RKOA status was less in KLG2 knees without JSN, and in KLG3 knees.

CONCLUSION

KLG2 knees with JSN and moderate contra-lateral RKOA, display relatively high rates of subregional femorotibial cartilage loss, despite being at a relatively mild stage of RKOA. They may therefore provide a unique opportunity for recruitment in clinical trials that explore the efficacy of anti-catabolic DMOADs on structural progression.

Long-term sequelae and management following anterior cruciate ligament injury

This article discusses a case in which a patient who sustained an anterior cruciate ligament (ACL) injury returned with anterior knee pain in the same knee approximately 20 years later. He underwent reconstruction at the time of the injury and had a revision reconstruction performed 10 years later. The case highlights the long-term consequences of ACL injury and subsequent reconstruction for the knee joint, as this patient has developed anterior knee pain during his mid-40s. Additionally, non-operative management of knee osteoarthritis is discussed.

Brief report: reconstruction of joint hyaline cartilage by autologous progenitor cells derived from ear elastic cartilage

In healthy joints, hyaline cartilage covering the joint surfaces of bones provides cushioning due to its unique mechanical properties. However, because of its limited regenerative capacity, age- and sports-related injuries to this tissue may lead to degenerative arthropathies, prompting researchers to investigate a variety of cell sources. We recently succeeded in isolating human cartilage progenitor cells from ear elastic cartilage. Human cartilage progenitor cells have high chondrogenic and proliferative potential to form elastic cartilage with long-term tissue maintenance. However, it is unknown whether ear-derived cartilage progenitor cells can be used to reconstruct hyaline cartilage, which has different mechanical and histological properties from elastic cartilage. In our efforts to develop foundational technologies for joint hyaline cartilage repair and reconstruction, we conducted this study to obtain an answer to this question. We created an experimental canine model of knee joint cartilage damage, transplanted ear-derived autologous cartilage progenitor cells. The reconstructed cartilage was rich in proteoglycans and showed unique histological characteristics similar to joint hyaline cartilage. In addition, mechanical properties of the reconstructed tissues were higher than those of ear cartilage and equal to those of joint hyaline cartilage. This study suggested that joint hyaline cartilage was reconstructed from ear-derived cartilage progenitor cells. It also demonstrated that ear-derived cartilage progenitor cells, which can be harvested by a minimally invasive method, would be useful for reconstructing joint hyaline cartilage in patients with degenerative arthropathies.

Relationship of gene expression in the injured human meniscus to body mass index: a biologic connection between obesity and osteoarthritis

OBJECTIVE

Higher body mass index (BMI) increases the risk of meniscus injury and knee osteoarthritis (OA). However, it is unknown if and how obesity affects meniscus biology. We analyzed transcriptome-wide gene expression profiles of injured human menisci to test the hypothesis that meniscal gene expression signatures relate to patient BMI.

METHODS

Meniscus samples were obtained from patients undergoing arthroscopic partial meniscectomy. Transcriptome-wide analysis of gene expression followed by validation of selected transcripts by QuantiGene Plex assay was performed. Correlations of gene expression with BMI and relative fold changes (≥1.5-fold) in 3 BMI categories (lean [BMI 18.5-24.9 kg/m(2) ], overweight [BMI 25.0-29.9 kg/m(2) ], and obese [BMI >30.0 kg/m(2) ]) were analyzed, and integrated functional classifications were probed computationally.

RESULTS

The obese versus overweight comparison resulted in the largest set of differences (565 transcripts) followed by obese versus lean (280 transcripts) and overweight versus lean (125 transcripts). Biologic reproducibility was confirmed by cluster analysis of expressed transcripts. Differentially regulated transcripts represented important functional classifications. Transcripts associated with oxygen transport, calcium ion binding, and cell homeostasis were elevated with BMI, while those related to extracellular matrix deposition, cell migration, and glucosamine metabolic processes were repressed. While these functional classifications may play key roles in cartilage/meniscus homeostasis, failure of extracellular matrix deposition and increase in calcium ion binding likely contribute to OA development following meniscal injury.

CONCLUSION

Our results indicate greater differences in gene expression between obese and overweight groups than between overweight and lean groups. This may indicate that there is a weight threshold at which injured meniscus responds severely to increased BMI. BMI-related changes in gene expression present a plausible explanation for the role of meniscal injury in OA development among obese patients.

Mechanical forces induce changes in VEGF and VEGFR-1/sFlt-1 expression in human chondrocytes

Expression of the pro-angiogenic vascular endothelial growth factor (VEGF) stimulates angiogenesis and correlates with the progression of osteoarthritis. Mechanical joint loading seems to contribute to this cartilage pathology. Cyclic equibiaxial strains of 1% to 16% for 12 h, respectively, induced expression of VEGF in human chondrocytes dose- and frequency-dependently. Stretch-mediated VEGF induction was more prominent in the human chondrocyte cell line C-28/I2 than in primary articular chondrocytes. Twelve hours of 8% stretch induced VEGF expression to 175% of unstrained controls for at least 24 h post stretching, in promoter reporter and enzyme-linked immunosorbent assay (ELISA) studies. High affinity soluble VEGF-receptor, sVEGFR-1/sFlt-1 was less stretch-inducible than its ligand, VEGF-A, in these cells. ELISA assays demonstrated, for the first time, a stretch-mediated suppression of sVEGFR-1 secretion 24 h after stretching. Overall, strained chondrocytes activate their VEGF expression, but in contrast, strain appears to suppress the secretion of the major VEGF decoy receptor (sVEGFR-1/sFlt-1). The latter may deplete a biologically relevant feedback regulation to inhibit destructive angiogenesis in articular cartilage. Our data suggest that mechanical stretch can induce morphological changes in human chondrocytes in vitro. More importantly, it induces disturbed VEGF signaling, providing a molecular mechanism for a stress-induced increase in angiogenesis in cartilage pathologies.

Targeted delivery to cartilage is critical for in vivo efficacy of insulin-like growth factor 1 in a rat model of osteoarthritis

OBJECTIVE

Acute articular injuries lead to an increased risk of progressive joint damage and osteoarthritis (OA), and no therapies are currently available to repair or protect the injured joint tissue. Intraarticular delivery of therapeutic proteins has been limited by their rapid clearance from the joint space and lack of retention within cartilage. The aim of this study was to test whether targeted delivery to cartilage by fusion with a heparin-binding domain would be sufficient to prolong the in vivo function of the insulin-like growth factor 1 (IGF-1).

METHODS

We produced a humanized and optimized recombinant HB-IGF-1 fusion protein. By injecting HB-IGF-1, IGF-1, or saline alone into the knee joints of adult Lewis rats, we tested whether fusion with a heparin-binding domain 1) altered the kinetics of retention in joint tissues, 2) prolonged functional stimulation as measured by radiolabel incorporation, and 3) enhanced efficacy in a rat model of surgically induced OA, using weekly injections.

RESULTS

Fusion of heparin-binding domain with IGF-1 prolonged retention in articular and meniscal cartilage from <1 day to 8 days after injection. Unmodified IGF-1 had no functional effect 2 days after injection, whereas HB-IGF-1 stimulated meniscal cartilage at least 4 days after injection. HB-IGF-1, but not IGF-1, significantly slowed cartilage damage in a rat model of OA.

CONCLUSION

Heparin-binding domain fusions can transform rapidly cleared proteins into potential intraarticular therapies by targeting them to cartilage.