Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2000-02-03
2001-08-07
Smith, Jeffrey A. (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
Reexamination Certificate
active
06270503
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for repairing a detached osteochondral flap. More specifically, the present invention relates to fixation of osteochondritis dissecans fragments using a parallel guide sleeve.
2. Description of the Related Art
Osteochondritis dissecans is a condition of complete or incomplete separation of a portion of joint cartilage and underlying bone. Usually involving the knee, the disorder also can affect the talar dome of the ankle and capitellum of the elbow. Reports of lesions in the shoulder, hands, wrist, and hip are rare. In the knee, the lesions are found most commonly on the medial femoral condyle, and less so on the lateral femoral condyle and the patella. On the medial femoral condyle, the lesions are most commonly found on the lateral, non-weight bearing surface.
Treatment usually involves osteochondral flap reattachment or abridement. Reattachment is preferred where possible, but the current methods of fixation using, e.g., a Kirschner wire, can be improved upon to simplify the technique and improve fixation strength.
SUMMARY OF THE INVENTION
The present invention provides a instrumentation for and a method of fixation of osteochondritis dissecans fragments using bioabsorbable chondral darts inserted through a clear guide sleeve. The instruments provide compression to an osteochondral fragment during insertion of the chondral darts below the surface of the articular cartilage. Dart insertion provides a strong, bioabsorbable fixation of smaller osteochondral flaps, particularly those of 5 mm to 20 mm in diameter. The present invention provides instrumentation that is designed for insertion of individual darts or, alternatively, multiple parallel dart insertion.
The single shot instruments of the present invention are designed to insert individual darts. The sheath is placed against the fragment to provide compression. A stainless steel trocar passes through the sheath to a controlled depth to form a hole. The chondral dart is inserted directly into the sheath and the sheath is positioned firmly over the drilled hole. The dart depth is controlled such that the dart is countersunk 2 mm below the surface of the cartilage into subchondral bone.
According to an alternative method of use and instrumentation, multishot instrumentation offers a controlled method to manage larger fragments using multiple darts. Clear guide sleeves, preferably having 2 or 4 parallel holes provide atraumatic compression to the fragment throughout the procedure while allowing the surgeon to see the passage of instruments and underlying fragment through the sheath. A set of drill pins having stepped lengths is used. The step design of the drill pins allows easy access for drilling and removing. These pins stabilize the guide sleeve to create necessary pilot holes for dart insertion. The dart is inserted through one of the channels into the subchondral bone 2 mm below the surface of the cartilage.
According to a preferred embodiment, darts are inserted by replacing drill pins in a last in, first out method. Thus, while holding the osteochondral flap fragment in place using the guide sleeve, a hole is drilled through the fragment and into the bone to a predetermined depth using the longest drill. The drill then is removed from the guide sleeve. A fragment-retaining dart implant is inserted into the hole to secure the fragment to the bone using the guide sleeve as a guide. The sequence then is repeated with the next longest drill, until all of the drills are removed. An auxiliary pin is used to hold the guide in place during the last installation sequence, which is performed using the shortest drill.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
REFERENCES:
patent: 4465065 (1984-08-01), Gotfried
patent: 4744353 (1988-05-01), MacFarland
patent: 5129906 (1992-07-01), Ross et al.
patent: 5250055 (1993-10-01), Moore et al.
patent: 5531751 (1996-07-01), Schulthesis et al.
patent: 5683400 (1997-11-01), McGuire
patent: 5766221 (1998-06-01), Benderev et al.
Arthrex Inc.
Ostrolenk Faber Gerb & Soffen, LLP
Robert Eduardo C.
Smith Jeffrey A.
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