ObjectivesTo define Patient Acceptable Symptom State (PASS) thresholds for the Oxford hip score (OHS) and Oxford knee score (OKS) at mid-term follow-up.MethodsIn a prospective multicentre cohort study, OHS and OKS were collected at a mean follow-up of three years (1.5 to 6.0), combined with a numeric rating scale (NRS) for satisfaction and an external validation question assessing the patient’s willingness to undergo surgery again. A total of 550 patients underwent total hip replacement (THR) and 367 underwent total knee replacement (TKR).ResultsReceiver operating characteristic (ROC) curves identified a PASS threshold of 42 for the OHS after THR and 37 for the OKS after TKR. THR patients with an OHS ≥ 42 and TKR patients with an OKS ≥ 37 had a higher NRS for satisfaction and a greater likelihood of being willing to undergo surgery again.ConclusionsPASS thresholds appear larger at mid-term follow-up than at six months after surgery. With- out external validation, we would advise against using these PASS thresholds as absolute thresholds in defining whether or not a patient has attained an acceptable symptom state after THR or TKR.Cite this article: Bone Joint Res 2014;3:7–13.

ObjectivesWe aimed first to summarise minimal clinically important differences (MCIDs) after total hip (THR) or knee replacement (TKR) in health-related quality of life (HRQoL), measured using the Short-Form 36 (SF-36). Secondly, we aimed to improve the precision of MCID estimates by means of meta-analysis.MethodsWe conducted a systematic review of English and non-English articles using MEDLINE, the Cochrane Controlled Trials Register (1960–2011), EMBASE (1991–2011), Web of Science, Academic Search Premier and Science Direct. Bibliographies of included studies were searched in order to find additional studies. Search terms included MCID or minimal clinically important change, THR or TKR and Short-Form 36. We included longitudinal studies that estimated MCID of SF-36 after THR or TKR.ResultsThree studies met our inclusion criteria, describing a distinct study population: primary THR, primary TKR and revision THR. No synthesis of study results can be given.ConclusionsAlthough we found MCIDs in HRQoL after THR or TKR have limited precision and are not validated using external criteria, these are still the best known estimates of MCIDs in HRQoL after THR and TKR to date. We therefore advise these MCIDs to be used as absolute thresholds, but with caution.

Purpose A major challenge in metastatic spinal disease is timely identification of patients. Left untreated, spinal metastases may lead to gross mechanical instability and/or neurological deficits, often requiring extensive invasive surgical treatment. The aim of this cohort study was to assess the correlation between delayed treatment of patients with spinal metastases and functional performance, quality of life and survival. Methods All patients surgically treated for metastatic spinal disease at a tertiary care facility were included for analysis. Patients who underwent elective surgery were considered as timely treated, whereas patients requiring emergency surgery were considered to be treated in a delayed fashion. EQ-5D scores, KPS scores and mortality rates were compared between the two groups. Results A total of 317 patients (215 timely treated, 102 delayed) had survivorship data available and 202 patients (147 timely treated, 55 delayed) had clinical data available. Multivariate analyses showed delayed treatment was associated with lower EQ-5D and KPS scores and higher mortality rates, independent of confounders such as baseline EQ-5D/KPS scores, neurological status, tumor prognosis and patient age. Conclusions The results from the present study show delayed treatment of patients with symptomatic spinal metastases has both direct and indirect adverse consequences for functional performance status, quality of life and survival. Optimization of referral pattern may accelerate the time to surgical treatment, potentially leading to better quality of life and survival.

Background: Symptoms associated with spinal metastases are often non-specific and resemble non-cancer-related. Therefore, patients with spinal metastases are at risk for delayed referral and treatment. Delayed presentation of symptomatic spinal metastases may lead to the development of neurological deficits, often followed by emergency surgery. Objective: The aim of this cohort study was to analyze the effect of delayed referral and treatment of spinal metastases on clinical outcome. Methods: We included all patients surgically treated for spinal metastases at our tertiary care center. Based on the (in)ability to undergo elective surgery, patients were identified as timely treated or delayed. Patient-and tumor-characteristics, surgical variables, and postoperative variables such as complication rate, the ability to return home and length of hospital stay were recorded and compared between the two groups. Results: Based on the urgency of treatment at admission, 206 patients were identified as timely treated and 98 as delayed. At baseline, the two groups did not differ significantly except for the extent of neurological symptoms. Timely treated patients underwent less invasive procedures (52.9% vs 13.3% percutaneous pedicle screw fixations), less median blood loss (200cc vs 450cc), shorter median admission time (7 vs 13 days), lower complication rate (26.2% vs 48.0%) and higher chances of being discharged home immediately (82.6% vs 41.1%) compared to delayed patients. Using multivariate regression models these correlations remained present independent of tumor prognosis, preoperative mobility and ASA-score. Conclusion: The delayed presentation of patients with spinal metastases to a spinal surgeon is strongly and independently associated with worse surgical and postoperative outcome parameters. Improvements in referral patterns could potentially lead to more scheduled care, negating the detrimental effects of delay.

Skeletal diseases and their surgical treatment induce severe pain. The innervation density of bone potentially explains the severe pain reported. Animal studies concluded that sensory myelinated A@-fibers and unmyelinated C-fibers are mainly responsible for conducting bone pain, and that the innervation density of these nerve fibers was highest in periosteum. However, literature regarding sensory innervation of human bone is scarce. This observational study aimed to quantify sensory nerve fiber density in periosteum, cortical bone, and bone marrow of axial and appendicular human bones using immunohistochemistry and confocal microscopy. Multivariate Poisson regression analysis demonstrated that the total number of sensory and sympathetic nerve fibers was highest in periosteum, followed by bone marrow, and cortical bone for all bones studied. Bone from thoracic vertebral bodies contained most sensory nerve fibers, followed by the upper extremity, lower extremity, and parietal neurocranium. The number of nerve fibers declined with age and did not differ between male and female specimens. Sensory nerve fibers were organized as a branched network throughout the periosteum. The current results provide an explanation for the severe pain accompanying skeletal disease, fracture, or surgery. Further, the results could provide more insight into mechanisms that generate and maintain skeletal pain and might aid in developing new treatment strategies.Perspective: This article presents the innervation of human bone and assesses the effect of age, gender, bone compartment and type of bone on innervation density. The presented data provide an explanation for the severity of bone pain arising from skeletal diseases and their surgical treatment.