Biomechanical evaluation of a new cross-pin technique for the fixation of different sized bone–patellar tendon–bone grafts

To overcome the disadvantages of interference-screw fixation of bone–patellar tendon–bone (BPTB) grafts, new fixation techniques for anterior cruciate ligament (ACL) grafts using biodegradable pins have been developed. The hypothesis of the present study was that cross-pin fixation techniques provide a primary stability that is comparable to that of interference screws. A biomechanical in vitro study was discussed. Human BPTB grafts of 8, 9 and 10 mm diameter were fixed in bovine knees with biodegradable cross pins (diameter: 2.0, 2.7 or 3.2 mm) or biodegradable interference screws. Stiffness and ultimate load were evaluated. For 9 and 10 mm BPTB grafts, no statistically significant difference in maximum load and stiffness was found between the four fixation techniques tested. For 8 mm bone blocks the maximum load of the 3.2 mm pins (274.2 N) was significantly lower than for the 2.0 mm pins (479.8 N) and the interference screws (504.0 N). Predominant failure mode in this group was bone-block fracture. Thicker grafts (9 and 10 mm) fixed with the 2.0 mm pins predominantly failed by implant fracture. Femoral fixation of 8, 9 and 10 mm BPTB grafts using cross pins leads to biomechanical properties that are comparable to biodegradable interference screws when tested by a single-cycle load to failure. Cross pins provide a rigid fixation for 9 and 10 mm BPTB grafts.     

Long-term results of arthroscopic Bankart repair: Minimum 10 years of follow-up

Purpose

This study investigated the long-term results of arthroscopic Bankart repair in terms of rates and timelines of recurrence of instability, with special interest in young adult patients aged ≤20 years.

Methods

Between 2000 and 2005, 186 shoulders [182 patients, 50 women, median age 26 (range 15–58) years] were operated on at a university hospital using arthroscopic Bankart repair because of instability after traumatic anteroinferior shoulder dislocation. Medical records were retrospectively reviewed and patients were assessed using postal questionnaires or telephone interview after a minimum of 10 years of follow-up [median 12.2 (range 10–16) years]. The primary outcome measure was recurrence of instability (assessed from 167 shoulders), other outcome measures included Oxford instability score (OIS), subjective shoulder value (SSV), and Western Ontario instability index (WOSI) (assessed from 157 shoulders).

Results

At the end of follow-up, 50/167 shoulders (30%) had recurrence of instability and 30/167 (18%) were subjected to reoperation due to instability symptoms. Twenty-six (52%) failures occurred within ≤2 years, 11 (22%) within 2–5 years, and 13 (26%) >5 years after surgery. Failure rate was 19/35 (54%) for patients aged ≤20 years and 31/132 (24%) for patients aged >20 years; reoperation rates were 11/35 (31%) and 19/132 (14%), respectively. Mean OIS was 20 (SD 9, range 12–50), SSV 83% (SD 21, range 10–100), and WOSI score 80 (SD 22, range 33–100).

Conclusions

Nearly one-third of patients had recurrence of instability after arthroscopic Bankart repair after a minimum of 10-year follow-up. Patients aged ≤20 years did poorly with more than half of the patients having recurrence; alternative stabilization techniques should probably be considered for these patients.

Level of evidence

IV.

     

A new “miniSTR-multiplex” displaying reduced amplicon lengths for the analysis of degraded DNA

A multiplex PCR was designed for the loci D2S1338, D16S539, D18S51, TH01 and FGA using redesigned primers in order to reduce the lengths of the amplification products compared to the designs used in commercially available multiplex PCR kits, also including amelogenin. The new PCR primers were used to amplify highly degraded DNA from casework samples, which had shown no or only poor results for these loci in previous analyses with standard primer sets. The application of the new miniSTR-multiplex resulted in an increased overall typing success rate for degraded DNA samples. In a concordance study between the conventional and the newly designed primers, no genotype differences were revealed in 124 randomly selected individuals.     

The “turn-over” technique for selective cerebral angiography

In older patients with severe aortic atherosclerosis or pronounced tortuosity of the brachiocephalic vessels, selective catheterisation may be impossible. In order to overcome this difficulty we introduced a new turn-over technique. This involves introduction of a long guidewire through the catheter, advancing it and turning it over just above the aortic valves and finally introducing it into each major vessel, followed by the catheter. Selective catheterisation was completely achieved with the turn-over technique in 13 patients. Turning over the catheter just above the aortic valves and introducing it into the vessels was very easy.     

A simple and safe technique for sterile autologous platelet labelling using “Monovette” vials

A simple technique of autologous platelet labelling is described, which allows labelling within 40 min, and has the advantage of low costs, as no laminar air flow is required. Blood (16 ml) was withdrawn into 4 ml ACD, 500 ng prostacyclin was added. After 10 min sedimentation the vials were centrifuged for 5 min at 150 g. The plateletrich plasma in the supernatant was centrifuged at 500 g for 10 min to obtain a platelet pellet. The platelet-poor plasma was preserved in a sterile syringe and the platelet pellet was resuspended in 1 ml tyrode buffer. The cell suspension was labelled at 37° C for 5 min with 100 Ci ¹¹¹In-oxine sulphate and reinjected after dilution with the plasma. Mean labelling efficiency was 90%±3%, mean recovery 2 h after reinjection 76%±3% (mean±SD).     

A new type of 81Rb81mKr generator for medical use

A new ⁸¹Rb^81mKr generator is described. The new generator-type is suitable for ventilation and perfusion studies. By implantation of 60 keV ⁸¹Rb⁺-ions into Mylar or polyethylene foils, the pure ^81mKr daughter can be eluted by an air-flow or by an isotonic NaCl solution.     

Sclerotherapy for venous malformations using a “negative subtraction” technique

We describe a technique of injecting alcohol into venous malformations (VM) under slow digital subtraction angiography (DSA) which eliminates the need to pre-mix the alcohol with a contrast agent. The technique presented here is especially helpful when Metrizamide is not available or not permitted for use. It offers an elegant way to visualize, in real time, the alcohol injected into the VM, while preserving its high concentration and potency as a sclerosing agent.     

The “paraglider-wing” sign: an arthroscopic indicator of partial-thickness bursal-surface tears of the supraspinatus tendon

Partial-thickness bursal-surface tears of supraspinatus tendon may be missed on preoperative investigations and can be overlooked at surgery if not specifically sought. The authors describe an arthroscopic sign to detect these tears, when they involve more than half the tendon fibres, from the articular-side of the joint. The "paraglider-wing" sign, visualized during diagnostic glenohumeral arthroscopy, is demonstrated as an upward bulge of the capsulo-tendinous layer through the bursal-surface tear, under pressure of the inflow fluid. A positive sign indicates (1) presence of a partial-thickness bursal-side tear of the supraspinatus tendon, (2) significant depth (stage II or III) of the tear, and (3) the medial extent of the tear along the length of the tendon. A meticulous subacromial bursoscopy and excision of the bursa is then performed to visualize the tear from the subacromial space. Repair of the tear is performed with a double-row suture anchor fixation technique; the medial row of sutures is passed through the intact region of the tendon using the "paraglider-wing" sign as a guide.     

Intraoperative seed placement for thoracic malignancy—A review of technique,indications, and published literature

PurposeThis review examines the role of permanent radioactive seed implantation in thoracic malignancy. This technique can be used intraoperatively to provide additional highly localized radiation therapy in cases where optimal oncologic margins are unattainable or to palliate unresectable disease.Methods and materialsRelevant trials were identified through a systematic literature search using Pubmed.ResultsThe intraoperative placement of brachytherapy seeds has been described after sublobar resection for non–small-cell lung cancer (NSCLC), where surgical margins are close or microscopically positive and in the presence of macroscopic residual disease. This brachytherapy technique is currently the focus of a randomized prospective trial in the USA in patients unfit for lobectomy for early-stage NSCLC.ConclusionsThis review summarizes the methods of brachytherapy seed placement and the published experience of brachytherapy implants within the thorax, also examining radiation safety and postoperative dosimetry. This technique has the potential to improve local control with optimal sparing of normal tissue owing to its highly conformal radiotherapy delivery.     

Predicting adherence of dose–volume constraints for personalized partial-breast irradiation technique

PurposeMulticatheter interstitial brachytherapy (MIB) and external-beam (EB) radiotherapy are established partial-breast irradiation (PBI) techniques. Although EB-PBI is widely available, it requires extra irradiated margins for target uncertainties. We examined the impact of EB-PBI on dose–volume constraints as compared to MIB-PBI.Methods and MaterialsAmong 653 patients receiving MIB-PBI between October 2008 and April 2020, consequent 159 patients after September 2018 were examined. Clinical target volume (CTV) included the lumpectomy cavity plus 1.0 cm. Planning target volume (PTV) for EB-PBI was defined as CTV with 1.0-cm expansion. Because the ratio of PTV to breast volume (RPB) was related to cosmesis, <25% of RPB was defined as suitable for the ipsilateral breast constraints. Preoperative breast size was classified as very small (<350 cm³), small (350–699 cm³), and medium or large (≥700 cm³). According to each category, the dose–volume constraints of the organs at risk were compared between the two PBI techniques.ResultsPatients including 84 very small, 59 small, and 16 moderate to large breasts were examined. Although RPB was suitable in all patients receiving MIB-PBI, it was achieved in 74 patients (46.5%) receiving EB-PBI (p < 0.0001). The suitable RPB in patients with very small, small, and moderate to large breast was 32.1%, 55.9%, and 100%, respectively (p < 0.0001). Normal-tissue constraints for the other organs could be satisfied in patients with moderate to large breasts.ConclusionAlthough EB-PBI may be an appropriate option for patients with moderate to large breasts, MIB-PBI could still be a crucial technique, especially for patients with small breasts.