The Orthopaedic literature suggests that up to 60% of the population will present with backache of such severity that they will seek medical help. The fair majority of these cases will be labelled “mechanical” in nature and will get better over time. In most instances, there won’t be a clear explanation for the backache.
Wrist pain is somehow different: it is usually positional, unlikely to just go away and generally has a specific patho-anatomical cause. A common presentation is a deep stabbing dorsal (back of the wrist) pain when the wrist is loaded with weight in maximum extension: the typical position of the wrist in the Yoga downward dog or chaturanga position or even just pushing yourself out of a chair. Our understanding of dorsal wrist pain has improved with the advent of wrist arthroscopy and better knowledge of wrist biomechanics.
The Scapho-lunate ligament is a very unique C-shaped ligament regulating all wrist movements in the same way that the anterior cruciate ligament synchronises knee movements. The integrity of this intrinsic ligament (especially the dorsal part), with its attachments to the extrinsic ligaments, is the key to understanding wrist pain. When it comes to the scapho-lunate ligament and wrist pain, there is a chicken-and-egg situation with a fallacy.
Let’s start with the fallacy first: There is no such thing as a ‘wrist sprain’ (that will get better from some icing and anti-inflammatories and rest), the way we see with an ankle sprain. However, the mountain biker might well tear his scapho-lunate ligament in a fall, as opposed to fracturing his wrist bones.
The chicken-and-egg situation deals with dorsal wrist pain where there was no specific injury, but rather stabbing pain when loading the wrist in hyperextension, followed by an ongoing dull ache after exercise or a busy day, sometimes keeping you from sleep. This pain has previously been associated with a ganglion (a friendly fluid-filled cyst arising from the scapho-lunate ligament), but our understanding is that the pain could be better explained by an insufficiency of the dorsal scapho-lunate ligament that begins with the loss of the tethering ligament (called the DCSL or Dorsal-capsular-scapho-lunate complex) to the extrinsic ligaments. Whether the ganglion caused the weakening of the ligament or whether the ganglion is the manifestation of the weakening of the ligament, we don’t know.
What we do know, is that the ligament weakening causes mechanical changes that load areas of the bone without cartilage on to each other, causing a significant inflammatory response (synovitis) in the wrist.
If you suffer from dorsal wrist pain, it is probably best to have it checked out sooner rather than later, as progression of this pain can cause further problems in the future.