What's New in Carpal Arthroscopy?

The earliest applications of arthroscopy in horses were centred on the carpus. The development of techniques appropriate for clinical use and reports of successful treatment served as a springboard for the discipline (McIlwraith 1983 & 1984; McIlwraith et al 1987). Carpal injuries have long been recognised as a major limiting factor in the training and racing of horses. As a result, arthroscopy of the carpal joints is dominated by, although not exclusive to, racehorses. On the surface, there is little that genuinely is “new” in this area. A review of the literature shows that publications on carpal arthroscopy were most numerous between 1980 and 1990 with numbers declining progressively in subsequent decades. Since the publication of the third edition of Diagnostic and Surgical Arthroscopy in the Horse (2005) there have been only three papers with new information, dealing with the palmar compartments of middle and antebrachiocarpal joints (Cheetham and Nixon 2006), use of a variable-pitched tapered compression screw for the repair of frontal plane slab fractures of the third carpal bone (Hirsch et al 2007) and repair of chip fractures (Wright and Smith 2011). This is important but nonetheless represents only part of the story as corporate experience accrues and techniques are refined, often never to appear in the literature.

Manifestations of adaptive osteochondral failure remain the most common indications in both middle carpal and antebrachiocarpal joints. These can take the form of both complete and incomplete fractures or fragmentation which can be marginal or non-marginal. If tissues are viable, mechanically tolerant, capable of healing and articular congruency is achievable then reconstructive techniques are indicated. When any of the above criteria are not met, and/or surgical trauma or morbidity risks outweigh potential advantages, then current concepts indicate that removal of fragments is logical. The goal, in this instance, is to leave the smallest possible articular deficit such that the second intention healing that ensues will minimise the articular insult and maximise mechanical and biochemical homeostasis. It is important to recognise that following loss of articular surface the joint is not returned to normal. All articular deficits produce incongruity, mal-loading of adjacent articular surfaces and micro-instability. These features, in turn, are limited by a conservative approach to lesion debridement following fragment removal such that as much viable osteochondral tissue as possible is retained. All techniques for arthroscopically guided repair of carpal fractures have evolved from the original concept of Richardson (1986) which enables minimally invasive, accurate reduction and use of percutaneous markers for delineation of fracture margins and implant trajectory.  [...]