Psychosocial predictors of outcomes up to one year following total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) aims to relieve pain and improve physical functioning of the knee, however, some patients continue to experience pain and impaired function following TKA which cannot be explained by surgical and implant factors. Psychological factors may influence the outcomes of TKA. The aim of this prospective study was to examine the psychosocial factors that predicted pain, stiffness and physical functioning up to one year following TKA.

METHODS

One hundred and two patients completed pre-operative and one-year questionnaires which assessed a wide range of psychosocial and sociodemographic factors prior to surgery. The Oxford Knee Score (OKS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain, Stiffness and Physical Functioning subscales were used as outcome measures. Pearson correlation analysis and multiple linear regression were conducted to examine relationships between predictor and outcome variables.

RESULTS

Regression analysis showed that regarding variance in WOMAC outcome measures post TKA, our model predicted 31% for physical functioning, 25% for pain and 29% for stiffness at one year. Regarding variance in OKS post TKA, the model predicted 36% at one year. Greater levels of depressive symptoms and neuroticism and worse pre-operative scores significantly predicted poorer outcomes.

CONCLUSIONS

The findings indicate that pre-operative psychosocial factors are important in understanding outcomes of TKA. Psychosocial factors could be considered during pre-operative assessment. Further research conducted on psychological interventions is needed within this population to determine whether early and one-year outcomes can be improved.

Acute kidney injury following prophylactic flucloxacillin and gentamicin in primary hip and knee arthroplasty

Background

Following concerns regarding the emergence of Clostridium difficile infection in 2010, we changed antibiotic prophylaxis in patients undergoing primary hip and knee arthroplasty from cefuroxime to flucloxacillin and single-dose (SD) gentamicin. A subsequent perceived increase in the incidence of post-operative acute kidney injury (AKI) led us to evaluate the AKI incidence between different prophylactic antibiotic regimes used at our centre.

Methods

We examined the incidence of AKI as defined by Kidney Disease: Improving Global Outcomes criteria in 1588 patients undergoing primary hip or knee arthroplasty from January 2010 to January 2015. Patients received the following prophylactic antibiotic regimes: 8 g flucloxacillin in four divided doses and SD gentamicin 1.5 mg/kg ideal body weight (IBW; maximum dose 120 mg; n = 400), 8 g flucloxacillin alone in four divided doses (n = 400), SD cefuroxime (n = 400), triple-dose (TD) cefuroxime (n = 188) and teicoplanin with SD gentamicin 1.5 mg/kg IBW (n = 200).

Results

The incidence of AKI was as follows: flucloxacillin and gentamicin (13%); flucloxacillin alone (8.5%); SD cefuroxime (2%); TD cefuroxime (0.5%); and teicoplanin and gentamicin (3%). Of the six patients who developed Stage 3 AKI, all were in the flucloxacillin and gentamicin group. The odds ratio for the development of AKI derived from a binary logistic regression model was highest in the flucloxacillin and gentamicin group [7.79 (95% confidence interval 3.54–17.14), P < 0.0001].

Conclusions

Our findings suggest that the use of prophylactic high-dose flucloxacillin and gentamicin should be used with caution in patients undergoing primary hip or knee arthroplasty without a clear advantage in reducing surgical site infections given the association with increased rates of AKI.

Acute Kidney Injury After Prophylactic Cefuroxime and Gentamicin in Patients Undergoing Primary Hip and Knee Arthroplasty-A Propensity Score-Matched Study

BACKGROUND

Perioperative acute kidney injury (AKI) can be associated with lower limb arthroplasty and increases morbidity, length of stay, and mortality. AKI is more prevalent in some antibiotic regimes compared with others. The aim of the present study is to assess the impact of cefuroxime (CEF), with or without gentamicin (±G), on AKI rates.

METHODS

A prospective cohort study involving patients undergoing hip or knee arthroplasty was performed, between September 1, 2015 and November 30, 2016. Prophylactic intravenous antibiotics were administered according to local policy. AKI was graded according to the validated Acute Kidney Injury Network criteria based on the changes from baseline serum creatinine values. Propensity score matching was performed to identify risk factors. The local audit department approved the study. Appropriate statistical analyses were performed.

RESULTS

A total of 2560 met the inclusion criteria, with a female preponderance (1447/2560; 56.5%). The mean age was 67.5 ± 10.7 years, with males being significantly younger (65.9 ± 10.9 vs 68.7 ± 10.4 years). AKI developed in 32 cases (1.25%). There was no difference in AKI rates between CEF alone and CEF in combination with gentamicin (1.07% vs 1.36%; P = .524). Overall 31/32 cases were Acute Kidney Injury Network stage I. AKI did not affect the length of stay. Postoperative infection rate was 7/2560 (0.27%). There were no incidences of Clostridium difficile-associated diarrhea. Multivariate analysis demonstrated an increased AKI risk with the use of intravenous gentamicin.

CONCLUSION

C ± G yields low rates of infection and AKI compared with high-dose penicillin-based regimes. It is a safe and effective choice for lower limb arthroplasty.

Knee manipulation for reduced flexion after Total Knee Arthroplasty. Is timing critical?

BACKGROUND

Reduced flexion following knee arthroplasty (TKA) may compromise patient's function and outcome. The timing of manipulation under anaesthesia (MUA) has been controversial. We present our experience in a high volume practice and analyse the impact of timing.

METHODS

All TKA patients requiring MUA from February 1996 to June 2015 under the care of a single surgeon were analysed. MUA was offered to patients who had ≤ 75° of flexion post-op, providing that they had 30° more flexion preoperatively. To address the impact of timing from primary surgery to MUA on flexion gain we looked at 3 groups: Group I ≤ 90 days, Group II 91-180 days and Group III > 180 days.

RESULTS

Sixty two out of 7,423 (0.84%) underwent MUA. The MUA patients were significantly younger than the overall TKA cohort 61.2 vs 70.5 years (p = < 0.01). The median duration between arthroplasty and MUA was 3.9 months (IQR 3.4, Range 1.6-72.5 months). Overall flexion gained at 6-12 Weeks and 1 year post MUA showed significant improvements of 20.9° (p = <0.01) and 25° respectively (p = < 0.01). The flexion gain in group I (≤ 90 days) was significantly better than group III ( > 180 days) both at 6 weeks and 1 year following MUA but not better than group II (90-180 days).

CONCLUSIONS

MUA is an effective treatment for reduced flexion following TKA and should be the first line of management after failed physiotherapy. It can still have benefit beyond 6 months but the gains become less effective with time.

Minimal Incision Total Hip Arthroplasty: A Concise Follow-up Report on Functional and Radiographic Outcomes at 10 Years

In 2005, we conducted a prospective randomized controlled trial that demonstrated that, compared with a standard incision, a minimal incision technique did not improve early outcomes of total hip arthroplasty (THA). There was concern that reduced exposure could compromise long-term outcome. For the current study, all surviving participants were invited to return for 10-year radiographic and clinical evaluation. Outcome scores were available for 152 patients (69.4%) from the original cohort, and radiographs were available for 126 (57.5%). The median duration of follow-up was 124 months. We did not find significant differences in functional status or radiographic outcome between the minimal and standard incision groups at 10 years. The 10-year implant survival rate was 99.1% (95% confidence interval [CI] = 97.3% to 100%) in the standard incision group and 97.9% (95% CI = 95.1% to 100%) in the minimal incision group (p = 0.57). We concluded that minimal incision THA performed by a high-volume surgeon does not compromise long-term results but offers no benefit over a standard incision.

LEVEL OF EVIDENCE

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

Five-year clinical and radiological outcomes in 257 consecutive cementless Oxford medial unicompartmental knee arthroplasties

Aims

Our aim was to examine the clinical and radiographic outcomes in 257 consecutive Oxford unicompartmental knee arthroplasties (OUKAs) (238 patients), five years post-operatively.

Patients and Methods

A retrospective evaluation was undertaken of patients treated between April 2008 and October 2010 in a regional centre by two non-designing surgeons with no previous experience of UKAs. The Oxford Knee Scores (OKSs) were recorded and fluoroscopically aligned radiographs were assessed post-operatively at one and five years.

Results

The median age of the 238 patients was 65.0 years (interquartile range (IQR) 59.0 to 73.0), the median body mas index was 30.0 (IQR 27.5 to 33.0) and 51.7% were male. There were no intra-operative complications. There was a significant improvement in the median OKS at six weeks (34, IQR 31.0 to 37.0), one year (38, IQR 29.0 to 43.0) and five years (37, IQR 27.0 to 42.0) when compared with the pre-operative scores (16, IQR 13.0 to 19.0) (all p = < 0.01). No patient had progressive radiolucent lines or loosening. A total of 16 patients had died by five years. The cumulative survival at five years was 98.8% and the mean survival time was 5.8 years (95% confidence interval 5.6 to 5.9). A total of seven OUKAs (2.7%) were revised; three within five years and four thereafter, between 5.1 and 5.7 years post-operatively. Five (1.9%) had re-operations within five years.

Conclusion

The proportion of patients requiring revision at five years is lower than that generally reported for UKA. These findings add support for the use of the cementless OUKA outside the design centre. Longer follow-up is required. Cite this article: Bone Joint J 2017;99-B:623–31.

Impact of a learning curve on the survivorship of 4802 cementless total hip arthroplasties

AIMS

Our aim was to report survivorship data and lessons learned with the Corail/Pinnacle cementless total hip arthroplasty (THA) system.

PATIENTS AND METHODS

Between August 2005 and March 2015, a total of 4802 primary cementless Corail/Pinnacle THAs were performed in 4309 patients. In March 2016, we reviewed these hips from a prospectively maintained database.

RESULTS

A total of 80 hips (1.67%) have been revised which is equivalent to a cumulative risk of revision of 2.5% at ten years. The rate of revision was not significantly higher in patients aged ≥ 70 years (p = 0.93). The leading indications for revision were instability (n = 22, 0.46%), infection (n = 20, 0.42%), aseptic femoral loosening (n = 15, 0.31%) and femoral fracture (n = 6, 0.12%). There were changes in the surgical technique with respect to the Corail femoral component during the ten-year period involving a change to collared components and a trend towards larger size. These resulted in a decrease in the rate of iatrogenic femoral fracture and a decrease in the rate of aseptic loosening.

CONCLUSION

The rate of revision in this series is comparable with the best performing THAs in registry data. Most revisions were not directly related to the implants. Despite extensive previous experience with cemented femoral components, the senior author noted a learning curve requiring increased focus on primary stability. The number of revisions related to the femoral component is reducing. Any new technology has a learning curve that may be independent of surgical experience. Cite this article: Bone Joint J 2016;98-B:1589-96.

Modification of a receptor-binding surface of epidermal growth factor (EGF): analogs with enhanced receptor affinity at low pH or at neutrality

Six mutants of human epidermal growth factor (EGF), which carry single point substitutions within a surface patch proposed to juxtapose the bound receptor, were prepared and characterized for receptor affinity and mitogenicity. Receptor affinities relative to EGF are G12Q > H16D > Y13W > Q43A approximately = H16A approximately = EGF >> L15A. Notably, the reduced receptor affinity of mutant L15A indicates that Leu15 probably contributes substantially to receptor binding whereas unaltered receptor affinities observed for analogs H16A and Q43A indicate that neither His16 nor Gln43 contributes significantly to this interaction. On the other hand, the observed enhanced receptor affinities of analogs G12Q, Y13W and H16D highlight surface loci where additional productive receptor-binding contacts can be introduced. Interestingly, at acidic pH analog H16A reveals substantially greater receptor affinity than that of EGF, a property which may offer enhanced therapeutic utility in acidic environments in vivo.

Screening of the PDE6B gene in patients with autosomal dominant retinitis pigmentosa

Each of the 22 exons and 140 bp of the 5' untranslated region of the gene encoding the beta-subunit of cGMP-phosphodiesterase (PDE6B) were screened by denaturing gradient gel electrophoresis for mutations in the DNAs of 54 unrelated individuals with autosomal dominant retinitis pigmentosa. Six different sequence variants were found in seven patients. Four of the sequence variants did not segregate with disease in the families of the respective probands and/or were present in control DNAs. The remaining two sequence variants, a Leu228His missense in exon 3 and a G to A transition in the tenth base of the splice acceptor site of intron 8, were both present in the same proband. One or the other of the two sequence variants was present in each affected member of the proband's small family and neither sequence variant was present in the one unaffected member nor in 75 unrelated controls. However, no effect on splicing of mRNA was observed in expression studies of DNA constructs containing the G to A transition. Therefore, mutations in PDE6B could not be shown to be the cause of adRP in this group of patients.

Differential effects of I kappa B molecules on Tat-mediated transactivation of HIV-1 LTR

The tat gene product of the human immunodeficiency virus type 1 (HIV-1) strongly induces the transcription directed by the viral long terminal repeat (LTR). Tat acts by interacting with a target RNA element located immediately downstream of the initiation site. In addition, the action of Tat appears to be assisted by the upstream DNA enhancer elements, including the binding sites for the NF-kappa B/Rel family of host transcription factors. In the present study, we demonstrate that Tat transactivation of the HIV-1 LTR is markedly inhibited by several cytoplasmic inhibitors of NF-kappa B/Rel, suggesting the critical involvement of these host transcription factors in the function of the viral Tat protein. Furthermore, the various NF-kappa B inhibitors appear to have differential effects on Tat. While I kappa B alpha, I kappa B beta, and p100 potently inhibit Tat-mediated transactivation, p105 fails to inhibit, but even moderately synergizes, the action of Tat. We further demonstrate that the action of these NF-kappa B/Rel inhibitors on Tat correlates with their inhibitory activities on the RelA subunit of NF-kappa B. Finally, we show that a degradation-resistant I kappa B alpha mutant is able to potently inhibit Tat-mediated activation of the HIV-1 LTR in both untreated and tumor necrosis factor alpha-stimulated T cells, thus suggesting that such an I kappa B alpha mutant may serve as a constitutive repressor of HIV-1 LTR.

Mutations in the PDE6B gene in autosomal recessive retinitis pigmentosa

We have studied 24 small families with presumed autosomal recessive inheritance of retinitis pigmentosa by a combination of haplotype analysis and exon screening. Initial analysis of the families was made with a dinucleotide repeat polymorphism adjacent to the gene for rod cGMP-phosphodiesterase (PDE6B). This was followed by denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism electrophoresis (SSCPE) of the 22 exons and a portion of the 5' untranslated region of the PDE6B gene in the probands of each family in which the PDE6B locus could not be ruled out from segregating with disease. Two probands were found with compound heterozygous mutations: Gly576Asp and His620(1-bp del) mutations were present in one proband, and a Lys706X null mutation and an AG to AT splice acceptor site mutation in intron 2 were present in the other. Only the affecteds of each of the two families carried both corresponding mutations.

Heart rate response of firefighters to actual emergencies. Implications for cardiorespiratory fitness

Heart rate (HR) and oxygen consumption (VO2) responses during actual fire-suppression emergencies were monitored in 10 male firefighters. These firefighters worked at 157 +/- 8 beats per minute (bpm) for 15 +/- 7 minutes. This was 88 +/- 6% of their previously determined HR max. Based on treadmill testing, the HR x VO2 relationship was established for each firefighter. The predicted VO2 derived from HR monitoring in actual emergencies was 25.6 +/- 8.7 mL.kg-1.min-1 or 63 +/- 14% of VO2 max (40.0 +/- 6.5 mL.kg-1.min-1). These values on the cardiorespiratory response to actual emergencies are very similar to results derived from studies employing fire-suppression simulations. Recommendations for the VO2 max of firefighters ranging from 33.5 to 42.0 mL.kg-1.min-1 that have been generated from simulation testing appear appropriate given the cardiorespiratory responses to actual emergencies.

Plasma free and sulfoconjugated catecholamines during sustained exercise

Previous research established a relationship between circulating sulfoconjugated norepinephrine (NE-SO4) and oxygen consumption at various exercise intensities. In this study, the stability of the NE-SO4 response was examined during sustained exercise at a constant relative intensity. Seven trained men bicycled at 78 +/- 3% of their maximal O2 consumption for 28 min and then rested on the ergometer for a comparable duration. After a 30-min rest, plasma samples were collected through an indwelling catheter at 7-min intervals during the exercise and recovery periods. Free NE and epinephrine increased sixfold during exercise. These changes were accompanied by increases in sulfoconjugated catecholamines, but only NE-SO4 achieved statistical significance (rest, 712 +/- 602; exercise, 1,329 +/- 1,163 pg/ml). This occurred at three collection periods (14, 21, and 28 min). Approximately 35, 52, and 95% of NE, epinephrine, and dopamine, respectively, existed as sulfoconjugated during exercise. Subject variation was present in the sulfoconjugated catecholamine response that could not be attributed to corresponding differences in circulating free catecholamine release. These findings implicate blood flow as a factor in the sulfoconjugation of NE, but not epinephrine or dopamine.

Impact of exercise training on plasma adrenocorticotropin response to a well-learned vigilance task

Plasma adrenocorticotropin hormone (ACTH), cortisol, heart rate, self-reported state anxiety and total reaction time responses in physically active (n = 8) and sedentary (n = 11) middle-aged men were compared during performance of a well-learned, psychologically challenging task. The groups were similar in age (active: 39.9 +/- 8.4 yr vs. sedentary: 44.4 +/- 7.2 yr) and trait anxiety (29.4 +/- 5.2 vs. 34.5 +/- 12.6), but they had different maximal oxygen consumption relative to lean body weight (68.6 +/- 7.1 vs. 44.7 +/- 4.6 ml.kg(-1).min(-1)). During performance of the psychological protocol, the total group had significant increases in heart rate and state anxiety, whereas both ACTH and cortisol remained near baseline levels. ACTH and cortisol were not different between the groups. The sedentary group exercise trained for 4 mo, which resulted in an 18% improvement in maximal aerobic capacity (vO2 max). Exercise intervention did not significantly alter the neuroendocrine response compared to pre-training values or compared to a corresponding control group. These findings suggest that enhanced cardiovascular fitness resulting from exercise training does not affect anterior pituitary-adrenocortical activity during performance of a practiced vigilance task.