The Arthroscope
Various instruments are required for arthroscopy of the wrist. First of all, the doctor needs an arthroscope. This is a very thin tube (1.9 – 2.7mm diameter) through which he can look into the joint.
The thickness of the arthroscope depends on which joint is to be examined. The smaller the joint, the smaller the diameter of the arthroscope. The arthroscope is equipped with a so-called trocar.
This allows the arthroscope to be inserted into the selected area. The tip with which the puncture was made can then be pulled out and the optics with light source and camera can be inserted through the remaining channel. There is an entrance on the optics to inject a salt solution into the joint, for example to flush the area under examination freely.
In order to remove the salt solution from the joint, there is also an access for suction on site. The same route that was used for the rinsing solution can be used by connecting a distribution tap (three-way tap) here. This can be used to alternately flush and suction.
As a further possibility, the joint can be punctured at a second location and suction can take place above it. The doctor does not look directly into the joint through the arthroscope; instead, the image is recorded by a small camera and transferred to a computer screen. The arthroscopy can thus be recorded, viewed repeatedly and given to the patient as a film to take home.
Since arthroscopy is now only rarely used as a purely diagnostic measure, additional instruments are required for surgical measures. An important one is the shaver. This is a rod that can be inserted through the arthroscope and at the end of which there is a movable knife that the surgeon can control by hand and use to remove selected areas of the joint.
Other instruments used include palpation hooks, grasping forceps, scissors and punches for miniature biopsies. The wrist is usually arthroscopied over the back of the hand. At the beginning, the various muscle tendons and bone protrusions are often marked out so that the doctor can find his way around more easily and fewer complications arise from injury to other structures.
In the next step, fluid is injected into the joint via a syringe. After 3-5ml a resistance should be felt, which is due to the filling of the joint space with the irrigation fluid. However, if instability is present, a larger amount of fluid is often injected until resistance is felt.
The reason for this is that in the case of instability, the various joint spaces of the wrist are connected to each other. Next, the syringe is removed and a 2-3 mm incision is made with a scalpel at the puncture site, which is then spread with blunt scissors. Now the arthroscope with the trocar can be inserted, and then the above mentioned instruments and tools can be connected and inserted.
