Treatment of Large Femoral and Tibial Bone Defects With Plate-Assisted Bone Segment Transport

OBJECTIVES

The purposes of this study were to assess clinical and radiographic outcomes following plate-assisted bone segment transport (PABST) in large bone defects of the lower extremities.

METHODS

DESIGN

Retrospective study of prospectively collected data.

SETTING

Level-1 trauma center located in Germany.

PATIENT SELECTION CRITERIA

Patients who underwent PABST and were at least 1 year postoperatively were included.

OUTCOME MEASURES AND COMPARISONS

Demographic data were collected. Radiographic apparent bone gap (RABG), time to consolidation, time to full weight-bearing, and consolidation index were calculated. Numeric rating scale, lower extremity functional scale (LEFS), and complications were assessed.

RESULTS

Fifteen patients [13 male; mean age 51 years (range, 20-75)] underwent PABST and had follow-up at a mean of 29.1 months. The tibia was affected in 8 and the femur in 7 patients. Preoperative RABG was 60 mm [interquartile range (IQR): 40-125], and bone defects were caused by septic nonunions in 73% of patients. Fourteen patients (93%) demonstrated consolidated transport callus at 7.3 months [95% confidence interval (95% CI), 6-8.5], and 9 patients (60%) demonstrated complete consolidation of both docking site and transport callus at 11.5 months (95% CI, 7.3-15.3). Postoperative RABG was 0.1 mm (IQR: 0-0.8), and consolidation index was 1.9 months/cm (95% CI, 1.3-2.5). All patients achieved full weight-bearing at 8.7 months (IQR: 6.5-10.3). LEFS was 42 (95% CI, 34-50), and numeric rating scale was 3 (95% CI, 2-4). Patients treated for tibial defects had a significantly higher consolidation rate compared with patients treated for femoral defects ( P = 0.040).

CONCLUSIONS

PABST demonstrated high consolidation of transport callus with few complications. Although full weight-bearing was achieved in all patients, complete consolidation of the docking site was only present in 60% of cases.

LEVEL OF EVIDENCE

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

Chlorophyll b is involved in long-wavelength spectral properties of light-harvesting complexes LHC I and LHC II

Chlorophyll (Chl) molecules attached to plant light-harvesting complexes (LHC) differ in their spectral behavior. While most Chl a and Chl b molecules give rise to absorption bands between 645 nm and 670 nm, some special Chls absorb at wavelengths longer than 700 nm. Among the Chl a/b-antennae of higher plants these are found exclusively in LHC I. In order to assign this special spectral property to one chlorophyll species we reconstituted LHC of both photosystem I (Lhca4) and photosystem II (Lhcb1) with carotenoids and only Chl a or Chl b and analyzed the effect on pigment binding, absorption and fluorescence properties. In both LHCs the Chl-binding sites of the omitted Chl species were occupied by the other species resulting in a constant total number of Chls in these complexes. 77-K spectroscopic measurements demonstrated that omission of Chl b in refolded Lhca4 resulted in a loss of long-wavelength absorption and 730-nm fluorescence emission. In Lhcb1 with only Chl b long-wavelength emission was preserved. These results clearly demonstrate the involvement of Chl b in establishing long-wavelength properties.