An Arthroscopic Second-Look Study on the Effect of Remnant Preservation on Synovialization of Bone-Patellar Tendon-Bone Allograft in Anterior Cruciate Ligament Reconstruction

PURPOSE

To assess the effects of preserved more anterior cruciate ligament (ACL) remnant on synovial coverage, knee stability, and function after bone patellar-tendon-bone (BPTB) allograft reconstruction through second-look arthroscopy and follow-up study.

METHODS

From June 2007 to February 2009, 51 patients received single bundle BPTB allograft ACL reconstruction and second arthroscopic examination. The patients were divided into 4 types according to the types of ACL remnant: type 1, 18 had bridging between the posterior cruciate ligament and the tibia; type 2, 21 had bridging between the intercondylar notch roof and the tibia; type 3, 4 had bridging between the lateral condyle and the tibia; and type 4, 8 subjects had no ACL remnants. Clinical results were evaluated with the KT-1000 maximum displacement test and Lysholm scale at mean 12.3- and 53.5-month follow-up. Second-look synovium coverage was recorded as follows: covering 25% or less, 25% to 50%, 50% to 75%, and more than 75%.

RESULTS

Mean percentage of synovium coverage, Lysholm scale, and KT-1000 side-to-side difference were poorer in types 3 and 4 than the other 2 types at mean 12.3-month follow-up without statistical differences. The result of the final follow-up was comparable with the first one. Four patients had ruptured grafts and accepted revision surgery. Three of them belonged to types 3 and 4, and 1 patient with sport trauma belonged to type 2. There were other 11 patients with different types of impingement and partial absorption of grafts.

CONCLUSIONS

Although lack of statistical power, follow-up study and second-look arthroscopy showed that preserved type 3 and 4 ACL remnant caused poorer synovium coverage and might lead to earlier failure when using BPTB allograft. Early minor laxity at 12.3-month follow-up seemed to be not progressive at the final follow-up.

LEVEL OF EVIDENCE

Level III, case-control study.

Expression, purification, and S-nitrosylation of recombinant histone deacetylase 8 in Escherichia coli

Histone deacetylase (HDAC) 8 is a zinc ion dependent enzyme involved in removing the acetyl group from the core histones and other proteins which belong to Class I HDACs. It was reported that nitric oxide (NO) is a key regulator of HDAC function and S-nitrosylation of HDAC2 induces chromatin remodelling in neurons. This work reports the successful recombinant expression of human HDAC8 in Escherichia coli with two plasmids and the purification and S-nitrosylation in vitro. It was found that HDAC8 can be S-nitrosylated by the NO donor S-nitrosoglutathione (GSNO) in vitro, and the activity of HDAC8 was significantly inhibited when incubated with GSNO and S-nitrosocysteine in a time- and dosage-dependent manner, but sodium nitroprusside (SNP), and dithiothreitol cannot reverse this inhibition. These observations support and extend the concept that NO may regulate HDAC8 function by S-nitrosylation.

[Arthroscopic Bankart lesion repair by double-row vertical mattress suture with anchors for anteroinferior glenohumeral instability]

OBJECTIVES

To introduce a new arthroscopic Bankart repair by vertical mattress suture with anchors, and to evaluate its clinical effectiveness.

METHODS

A new arthroscopic Bankart repair by vertical mattress suture with anchors was performed, including to insert only 2 anchors at 3 o'clock and 5 o'clock position and make vertical mattress suture of labrum-ligament complex at 2, 4 and 6 o'clock of labrum, and to shift up the anterior-inferior capsule. Nine cases of anterior glenohumeral instability without severe glenoid bone defect were followed-up for an average period of 14 months (range from 6 to 26 months). The average surgery age was 28 years (range from 21 to 46 years).

RESULTS

The average surgery time was 51 min (40 - 75 min). Clinical scores as evaluated by the modified Rowe score advanced from 40 +/- 16 points to 92 +/- 19 points (75 - 94). There was no any recurrence and complication. External rotation was reduced by 5 degrees at 0 degrees adduction and by 3 degrees at 90 degrees of abduction.

CONCLUSIONS

The arthroscopic Bankart repair by vertical mattress suture with anchors for anteroinferior glenohumeral instability is favorable as an easy, short-time surgery with excellent clinical results in short-term follow-up.

Structure of an acidic phospholipase A(2) from the venom of Deinagkistrodon acutus in a new crystal form

The three-dimensional structure of an acidic phospholipase A(2) purified from the venom of Deinagkistrodon acutus (Agkistrodon acutus) was determined in a new crystal form by molecular replacement at 0.28 nm resolution with a crystallographic R factor of 21.9% (R-free=25.7%) and reasonable stereochemistry. Being similar to the previous reported crystal form, a significant conformational adaptation of segment 14-23 at the dimer interface was observed. This segment was related to the "interface recognition site" (IRS). It was found that a positively charged residue at position 34 seems to be a common feature for most of hemolytic PLA(2)s belonging to group II. Structural comparison between the two crystal forms showed that NaCl had significant effects on the crystal packing, thus leading to dramatic changes of the unit cell parameters. In the new crystal form, MPD (2-methyl-2, 4-pentanediol) molecules exist in the hydrophobic channel of the enzyme.

Stability of interleukin 1 beta (IL-1 beta) in aqueous solution: analytical methods, kinetics, products, and solution formulation implications

The thermal stability of IL-1 beta in aqueous solution as a function of temperature (5-60 degrees C), pH (2-9), buffer (acetate, citrate, tris, and phosphate), and cyroprotectants (sugars, HSA) was investigated in this study. The analytical methodologies included RP-HPLC, SEC, ELISA, IEF-PAGE, SDS-PAGE, and bioassay. The degradation and inactivation of IL-1 beta at or above 39 degrees C were attributed to autoxidation of the two cysteine residues in the denatured protein, followed by hydrophobic/covalent aggregation and precipitation. At or below 30 degrees C, IEF- and SDS-PAGE results suggest a possible deamidation reaction. The difference in mechanism of degradation precludes the prediction of formulation shelf life from accelerated temperature data. Nonetheless, the good stability observed at 5 degrees C suggests that a solution formulation may be feasible for IL-1 beta.