Pyoderma Gangrenosum After Bilateral Total Knee Arthroplasty

Pyoderma gangrenosum is a neutrophilic dermatosis, which mimics both infection and necrotizing fasciitis, that can present after surgical interventions. We present the case of a 62-year-old male who underwent one-stage bilateral total knee arthroplasty. Nine days after the surgery, he presented with wound breakdown, high fever, and elevated white blood cell count. Repeated debridement was performed, and empiric antibiotics were given. All tissue cultures and aspirates remained negative throughout treatment course, and the patient remained unresponsive to therapy. The patient was eventually diagnosed with pyoderma gangrenosum after infectious etiologies were ruled out and after a skin biopsy and dermatologic consultation. His condition rapidly improved after treatment with corticosteroids, and soft-tissue defects were repaired with skin substitute and full-thickness skin grafting. In patients with aseptic wound breakdown after total knee arthroplasty, pyoderma gangrenosum is a rare but devastating complication and should be considered.

Lateral intercostal artery perforator (LICAP) flap for breast volume augmentation: Applications for oncoplastic and massive weight loss surgery

Background

Lateral intercostal artery perforator (LICAP) flap for breast volume augmentation provides the benefits of addressing axillary tissue excess and avoiding intramuscular dissection. Previous experience with the LICAP flap in patients with prior breast conservation therapy (BCT) has led to the development of an extended version for massive weight loss (MWL) patients as well.

Methods

A retrospective review of all cases of LICAP flaps was performed by a single surgeon. Data were subsequently extracted and analyzed including patient demographics, indication and timing of volume augmentation, complications, and follow-up length.

Results

From 2016 to 2020, 12 patients underwent 16 LICAP flaps for volume augmentation. Indications for volume augmentation included deficits from prior oncologic surgery (ten patients) and loss of volume due to MWL (two patients). The average BMI was 29.9 kg/m². Among the oncologic group, eight patients had delayed reconstruction, while two were immediate. Nine patients underwent radiation prior to volume augmentation. Eight of the 14 patients simultaneously received fat grafting. There were 4 cases of delayed wound healing that improved with local wound care. There were no statistically significant differences in complication rates between the oncologic and MWL groups. The average length of follow-up was 11.4 months.

Conclusions

This study supports that the application of the LICAP flap can be effectively broadened from the oncologic population to the MWL population. If needed, extending the flap provides an option to simultaneously address excess axillary and back tissue.

Short-term results of a new self-locking cementless femoral stem: a prospective cohort study of the Lima MasterSL

BACKGROUND

Total hip arthroplasty is a successful treatment for hip osteoarthritis. Primary and secondary implant fixation is dependent on implant design and plays an important role in the longevity of an implant. In this study, we assessed the self-locking cementless Master^SL femoral stem.

MATERIALS AND METHODS

In this single-centre prospective study, 50 consecutive hips with the indication for total hip arthroplasty, who met the inclusion criteria, received the Master^SL stem from LIMA Corporate. Patients had pre- and post-operative clinical and radiological assessment and completed patient-reported outcome measures [Oxford Hip Score (OHS), Harris Hip Score (HHS) and Forgotten Joint Score (FJS)] at the 6-week and 6-, 12- and 24-month mark. Post-operative X-rays were assessed for osteointegration (Engh Score), alignment and subsidence.

RESULTS

After 2 years, aseptic survival was 100%. One hip had to be explanted due to early deep infection and was excluded from the study. At 2 years, the patients reported a significant improved HHS and OHS of 95.3 ± 5.8 and 46.1 ± 3.6 (mean ± standard deviation), respectively, compared to preoperatively. The mean ± standard deviation for the FJS was 86.4 ± 18.7 with two-thirds of the patients reporting a score above 85. The mean Engh score is 15.1 ± 5.9 (mean ± standard deviation) with no patient scoring below 1 which suggests good osteointegration in all femoral stems.

CONCLUSIONS

The Master^SL femoral stem performed well in this short-term follow-up study, with high patient satisfaction and good signs of osteointegration. Long-term follow-up will be necessary to evaluate longevity.

LEVEL OF EVIDENCE

Level 3, Prospective cohort study.

TRIAL REGISTRATION

The study was registered on the 30.03.2016 with Australia New Zealand Clinical Trials Registry (ACTRN12617000550303).

Measurement of the tensor structure function b1 of the deuteron

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <x> <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <Q2> <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Evidence for quark-hadron duality in the proton spin asymmetry A1

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2 above 1.6 GeV2.

Q2 dependence of nuclear transparency for exclusive rho0 production

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle straight phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinstraight phi moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.