CONCLUSION

Our study of using modern biodegradable implants in osteoplastic stabilization of shoulder joint with bone defect more than 20 % of scapula

articular surface showed its effectiveness and safety in patients of young and active working age (2A in the Oxford CEBM Levels of Evidence).

BIODEGRADABLE IMPLANTS IN TREATMENT

OF CHRONIC POSTTRAUMATIC ANTERIOR

SHOULDER INSTABILITY WITH BONE DEFECT

OF SCAPULA ARTICULAR PROCESS

Vasily V. Monastyrev, Vyacheslav Y. Vasilyev, Marina E. Puseva, Nikolay S. Ponomarenko

Irkutsk Scientific Centre of Surgery and Traumatology, Irkutsk, Russia

INTRODUCTIONBone defect of scapula articular process is the major cause of recurring chronic posttraumatic shoulder instability. It requires surgical treatment for anatomical-functional stabilization of humeral head. For estimation of the bone defect volume MSCT with 3D-rectonstruction of scapula articular process is used. If the bone defect is more than 20 % of scapula articular surface, free iliac crest autograft is applied. The autograft is fixated to the bone defect with two metal screws using standard technique (fig. 1).

MATERIALS AND METHODSNovember 2010 – December 2015 – admission of the patients to theclinic of Irkutsk Scientific Center of Surgery and Traumatology foropen single-center controlled randomized partially blind study.

Inclusion criteria: 1) traumatic primary shoulder dislocation; 2) one-side injury of shoulder; 3) two and more shoulder dislocations in theanamnesis; 4) postoperative recurrence of shoulder dislocation;5) bone defect of anterioinferior margin of scapula articular process notless than 20 % of scapula articular surface; 6) age – 18–60 years.

Exclusion criterion: III–IV degree of blade-humerus jointosteoarthrosis.26 patients in total – the group of treatment (10 patients,biodegradable screws) and the group of comparison (16 patients,metal screws).

Biodegradable screwsWe used 4.5 mm biodegradable compressing screws (ActivaScrew™ PLGA 85L/15G) which maintain strong fixation during first 8 weeks after the insertion with full degradation within about 2 years. The polymers dissolve in vivo during hydrolytic degradation into α-hydroxyacids, which are excreted metabolically. The screws are compatible with AO instruments and have metal single-use adaptor for insertion.

X-ray diagnosticsPreoperative period: standard two-dimensional X-rays, multi-layer spiral CT with 3D-reconstruction of shoulder (intact and injured side). This allowed us to estimate and to plan the extent of surgical procedure. Postoperative period: check-up X-ray of operated shoulder (right after the surgery) and CT-3D (in 3 months after the surgery).

RESULTSThe results of surgical treatment were estimated within 12 months after the surgery (fig. 2, 3).

DISCUSSION3D-reconstruction of glenoid cavity allows us to estimate bone defect zones (location) and to calculate bone defect size (width, length, thickness) and its area in comparison with intact side. Inclusion and exclusion criteria for osteoplasty (bone defect more than 20 %) and autograft size are determined.

Advantages of using biodegradable implants: ▪ no repeated surgeries for the implant removal are required (which

also means lesser financial load for insurance companies);▪ lowering the chances of technical difficulties (i.e. metal screws, bone

canals from the screws, latent infection in the area of metal implants etc.) in case of repeated surgeries of an operated segment;

▪ opportunity of using any visualization methods without risk of artefacts.

AIMTo assess the effectiveness and safety of biodegradable implants in the treatment of chronic posttraumatic anterior shoulder instability under conditions of glenoid cavity margin bone defect of more than 20 % of scapula articular surface.

Limitations of metal screws application: reoperation is necessary (to remove the implant); screws may become artefacts in further MRI scanning; metal may affect biological tissues.

We did not observe either any failures of union, formations of false joint,

screw fractures in bone tissue nor any postoperative complications,

such as hematomas, infections, or synovitis.

Fig. 2. Patient K., comparison group. CT-3D before (a, b) and after (c, d) the surgery

a b

c d

Fig. 1. Scheme of fixation of an implant

Rowe Score for Instability:

the group of treatment – 14,9 points

increase (in 6 months).

ASES Shoulder Score: the group

of treatment – 11,6 points increase.

Range of motions in shoulder

joint (in 6 months): 35° increase

in abduction, 25° - in external

rotation (р < 0.05) (fig. 4). a b

c d

Fig. 3. Patient N., treatment group. CT-3D before (a, b) and after (c, d) the surgery

X-ray evidence: consolidation

of free autograft without osteolysis

or widening of a drilled hole.

The proper (edge-to-edge with

the joint) position of bone autografts.

Range of motions in shoulder joint (abduction )

Median; Box: 25%-75%; Whisker: Non-Outlier Range

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Fig. 4. Range of motions (abduction, external fixation) in treatment and comparison groups before and in 3, 6 and 12 months after the surgery.

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