02/07/2010
AO Technical Commission Approved

Headless Compression Screw 4.5 mm and 6.5 mm

Fixation of small and large bone fragments require meticulous reconstruction of the articular surface while preserving the surrounding cartilage and soft tissues. In order to achieve stable fixation with primary bone healing, the application of suitable controlled compression is preferred to support a high clinical success rate. Standard screws are problematic in intraarticular applications and in areas with little soft tissue coverage. Protruding heads may damage the joint surface or irritate soft tissue. Therefore, an adequately sized lag screw would be beneficial, one that could be buried below bone surface, for example, in the knee, ankle and foot.

The headless compression screw (HCS) 4.5 and 6.5 function the same way as the existing HCS 2.4 and 3.0. The design of the HCS 4.5 and 6.5 is specifically adapted to treat fractures, osteoarthritis or deformities of small to large bones. The HCS 4.5 is primarily intended for the calcaneus, talus, metatarsus, distal and proximal tibia, distal femur, as well as proximal humerus. The HCS 6.5 may be used for all the above except the proximal humerus.

The headless compression screw 4.5 comes in lengths of 20110 mm with short thread (shaft thread lengths 722 mm) and 30110 mm with long thread (shaft thread lengths 1244 mm).

The headless compression screw 6.5 comes in lengths of 30150 mm with short thread (shaft thread lengths 16 mm), and 45150 mm with long thread (shaft thread length 32 mm).

For the large size HCS the same instrumentation as for the existing HCS can be used. The only additional ones are the attachment for compression sleeve for powered screw insertion, drill bit for predrilling the near cortex, and sleeve for compression sleeve.

Case 1: 62-year-old white female with right stage II posterior tibial tendon insufficiency and II and III overload due to medial cuneiform first metatarsal joint instability treated with UCBL for 6 months after she complained of severe pain and increasing swelling

Case provided by Juan Bernardo Gerstner Garcs, Cali, Colombia

A medial displacement osteotomy of the calcaneus and transfer of the tendon of the flexor digitorum longus to the navicular fixed with an interference screw were performed (see Fig 2a-c). A fusion of the first medial cuneiformmetatarsal I, II, and III modified. Weil osteotomy was performed as well.

The talar axis is aligned to the midshaft of the first metatarsal (see Fig 3a-d).


Case 2: 67-year-old white female

Case provided by Juan Bernardo Gerstner Garcs, Cali, Colombia

Stage II of her left posterior tendon dysfunction and tarso/metatarsal, instability visible on x-ray (see Fig 1a-c).

A medializing calcaneal osteotomy was performed and fixed with two 6.5 mm HCS, a flexor hallucis longus transfer to her navicular is secured with an interference 7 mm screw and a lapidus procedure fixed with two crossing 4.5 HCS (see Fig 2a-b).

Progressive weight bearing was permitted at 8 weeks and UCBL was advised until the fourth postoperative month (see Fig 3a-b).

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