Purpose. Traumatic articular cartilage (AC) defects are common in young adults and frequently progresses to osteoarthritis. Matrix-Induced Autologous Chondrocyte Implantation (MACI) is a recent advancement in cartilage resurfacing techniques and is a variant of ACI, which is considered by some surgeons to be the gold standard in AC regeneration. MACI involves embedding cultured chondrocytes into a scaffold that is then surgically implanted into an AC defect. Unfortunately, chondrocytes cultured in a normoxic environment (conventional technique) tend to de-differentiate resulting in decreased collagen II and increased collagen I producing in a fibrocartilagous repair tissue that is biomechanically inferior to AC and incapable of withstanding physiologic loads over prolonged periods. The optimum conditions for maintenance of chondrocyte phenotype remain elusive. Normal oxygen tension within AC is <7%. We hypothesized that hypoxic conditions would induce gene expression and matrix production that more closely characterizes normal articular chondrocytes than that achieved under normoxic conditions when chondrocytes are cultured in a collagen scaffold. Method. Chondrocytes were isolated from Outerbridge grade 0 and 1 AC from four patients undergoing total knee arthroplasty and embedded within 216 bovine collagen I scaffolds. Scaffolds were incubated in hypoxic (3% O2) or normoxic (21% O2) conditions for 1hr, 21hr and 14 days. Gene expression was determined using Q-rt-PCR for col I/II/X, COMP, SOX9, aggrecan and B actin. Matrix production was determined using glycosaminoglycan (GAG) content relative to cell count determined by DNA quantification. Cell viability and location within the matrix was determined by Live/Dead assay and confocal microscopy. Statistical analysis was performed using a two-tailed T-test. Results. Chondrocytes cultured under hypoxic conditions showed an upregulation of all matrix related genes compared to normoxic conditions noted most markedly in col II, COMP and SOX9 expression. There were similar numbers of chondrocytes between hypoxic and normoxic groups (P=0.68) but the chondrocytes in the hypoxic group produced more GAG per cell (P= 0.052). Viable cells were seen throughout the matrix in both groups. Conclusion. Important matrix related genes (col II, COMP, SOX9) were most significantly upregulated in hypoxic conditions compared to normoxic conditions. This was supported by an increase in GAG production per cell in hypoxic conditions. The results indicate that hypoxia induces an upregulation in the production of extracellular matrix components typical of AC with only modest increases in col I (possibly related to the col I based scaffold used in this experiment). These results indicate that hypoxic conditions are important for the maintenance of chondrocyte phenotype even when the cells are cultured in a 3D environment. In conclusion, hypoxic culture conditions should be used to help maintain chondrocyte phenotype even when culturing these cells in a 3D scaffold

Introduction. Measuring the step off during total knee replacement (TKR) is a newly developed operative strategy (“spacer technique”; Heesterbeek et al, KSSTA 2014;22(3):650–9) to determine the optimal contact point (CP) of the femur with the tibia postoperative and to balance the posterior cruciate ligament (PCL) in cruciate-retaining TKR. Engineers have calculated the ideal step off for every size of the TKR, for which the tibiofemoral contact point in 90° will be at the designed position. With this study we determined the postoperative CP in CR-TKA and investigated whether (adverse) clinical outcome was correlated with the CP. Methods. 23 patients presenting with non-inflammatory osteoarthritis, a good functioning PCL, and indication for surgery with a PCL-retaining TKR were selected. Intraoperative PCL balancing was performed with the spacer technique. At 3 months postoperative, a pair of mediolateral radiographs was made using a set-up used for radiostereometric analysis (RSA). The patient was positioned standing with the operated leg in 90 degrees, 50% weight-bearing, knee flexion on a 30 cm-step. Model-based RSA software (RSAcore) was used to determine the 3D positions of the femur and tibia component, that were exported to custom-written software for determining the CP. The CP was defined as the point with the smallest distance between both the medial and lateral femur condyles and tibia plateau. It is expressed as the ratio of the anterior-posterior CP distance and the maximum anterior-posterior tibia plateau size, with 0 being anterior, 1 being posterior. Patients with reduced flexion capacity at follow-up, leading to manipulation under anaesthesia and/or scopic releases, were categorized as COMP, the other patients as no-COMP. CP was compared between these groups. Results. Preliminary data show that the mean medial CP of the total group was 0.51 (sd 0.05), mean lateral CP was 0.61 (sd 0.03) (p<0.001). Six out of 23 patients had flexion-related complications and for this reason further patient inclusion was stopped. The medial CP of the COMP-group (n=6) was at 0.54 (sd 0.01), which was significantly more posterior than the medial CP of the no-COMP group (n=17) (0.50 (sd 0.05)) (p=0.004). (Figure 1) The lateral CP was similar for both groups (p=0.76). Discussion. The medial CP relates to clinical outcome; patients with reduced flexion capacity had a more posterior CP. This might be an indication for a too tightly balanced PCL, but we need to investigate this further. None of the patients had a medial CP at the theoretically optimal position

Total knee arthroplasty is a reliable and durable solution to knee arthritis that fails conservative management. However, there are clinical pitfalls awaiting the surgeon, which can be avoided with forethought and analysis. The majority of early TKR failures are related to technical error on the part of the surgeon! The top 10 errors are: . 10. The knee attached to secondary gain: worker's comp, depression, etc. will make a successful outcome less likely. 9. Wound complications: raising large subcutaneous flaps, failure to respect pre-existing incisions about the knee, and delay in obtaining closure with flaps, etc. will almost guarantee infection!. 8. Prolonged observation of the draining wound: another invitation to infection!. 7. Internal rotation of the femoral component: patellar maltracking, and flexion instability await!. 6. Infection: discipline for the OR staff and surgeon alike are necessary to minimise this complication. 5. Varus position of the tibial component: early loosening and accelerated polyethylene wear are assured. 4. Failure to restore a neutral mechanical axis of the limb: early wear and loosening are the outcome of failure to pay attention to this very important basic principle of TKR. 3. Patellar tilt or dislocation: lateral retinacular release is less common with current designs, but is still required for proper patellar tracking. 2. Failure to balance soft tissue: collateral ligament, and the posterior cruciate ligament must be balanced throughout the range of motion for a successful result. And the #1 way to ruin a good result is…. Operating too early! Don't operate on the x-ray, and exhaust all reasonable conservative therapy and non-arthroplasty alternatives before resorting to prosthetic arthroplasty. The patient needs to understand the limitations of technology, and have reasonable expectations. Make sure the pre-op symptoms justify the procedure!

Aims

The increase in prescription opioid misuse and dependence is now a public health crisis in the UK. It is recognized as a whole-person problem that involves both the medical and the psychosocial needs of patients. Analyzing aspects of pathophysiology, emotional health, and social wellbeing associated with persistent opioid use after injury may inform safe and effective alleviation of pain while minimizing risk of misuse or dependence. Our objectives were to investigate patient factors associated with opioid use two to four weeks and six to nine months after an upper limb fracture.