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The PIP joint can dislocate dorsally, laterally or volarly. Most dislocations can be treated con-servatively, the exception being an unstable frac-ture-dislocation.

Lateral injury to the PIP joint

Injuries to the collateral ligaments occur more frequently on the radial aspect of the joint and often have some involvement of the volar plate.

They result from unilateral stress applied to the

extended digit. A ligament injury can be regarded as a sprain if the injured joint has sufficient capsular support to prevent displacement under appropriate stress. If the lateral stress test produces a deformity of greater than 20 degrees, this will indicate complete disruption of the collateral ligament. These injuries are managed conserva-tively following reduction.

In the acute phase, these injuries are painful and accompanied by significant oedema which effec-tively ‘splints’ the joint in a semi-flexed position.

While the oedema has some protective role, its prolonged presence will prevent movement and will result in adherence of joint structures.

Treatment

Oedema control and protective splinting A single layer of 2.5 cm Coban wrap is applied to the digit in a distal to proximal direction. This is applied with great care to avoid lateral stress to the PIP joint. The finger is then rested in a thermoplastic finger splint in slight PIP joint flexion, i.e about 20 degrees if volar plate involvement is suspected or in maximum extension if the injury is regarded as a sprain of the collateral ligaments. The splint is worn for the first 3 to 7 days following injury to allow Figure 11.4. The injured PIP joint usually presents

with soft swelling in the early stages after injury, and later with fibrotic periarticular thickening. Note the absence of skin creases over the PIP joint. Stiffness of both IP joints is common.

Figure 11.5. A single layer of Coban is applied to the swollen digit. A dorsal finger splint provides support during the first few postinjury days. If involvement of the volar plate is suspected, the PIP joint is placed in slight flexion, otherwise the IP joints are splinted in maximum extension. This may not be achievable on the first visit.

pain and swelling to settle. This period may be extended if there has been complete rupture and significant pain and swelling (Fig. 11.5).

Exercises

Gentle active stabilized IP joint flexion/extension exercises are then commenced through the Coban wrap. These exercises are performed on an hourly basis with 5 to 10 movements initially. As tolerance to exercise improves, the number of movements is increased. Movements are carried out gently and slowly and the end range position should be held for several seconds before the movement is repeated (Fig. 11.6).

Buddy-strapping

After the splinting period, the injured finger is taped to an adjacent digit to provide lateral support during activity. Coban wrap and Micropore tape are both suitable for this purpose. A buddy-strap fashioned from Velcro can be used if the joints of the two adjoining fingers are relatively level.

Intrinsic stretches

Adherence of the lateral bands or oblique reti-nacular ligament can occur following injury to the collateral ligaments. To help prevent contracture,

intrinsic stretches are incorporated into the exer-cise programme. The intrinsic muscles are stret-ched by holding the MCP joints in the extended position while passively flexing the IP joints (Fig.

11.7). This is followed by stabilized active DIP flexion exercises with the PIP joint held in extension; this manoeuvre places the oblique retinacular ligament on maximum stretch.

Overcoming PIP joint flexion deformity The first line of defence in correcting and control-ling a PIP joint flexion deformity is a neoprene fingerstall. The stall can be sewn in minutes and is easily applied and removed. It controls oedema, allows flexion and frequently reduces joint pain (Fig. 11.8). To gain the last 20 degrees or so of extension range, a Capener splint may be required (Fig. 11.9). Efforts to overcome the flexion deformity need to be balanced with consistent attention to regaining passive/active flexion range at both IP joints. The patient is advised to wear the neoprene stall around the clock other than when performing hourly flexion exercises.

Flexion strapping of interphalangeal joints Where IP joint stiffness is marked, gentle flexion bandaging prior to active exercise is recommended.

An IP joint flexion strap made from neoprene is used when the patient has achieved sufficient flexion range to hold the strap in place. Coban wrap (25 mm) or Microfoam tape also make effective flexion straps (Fig. 11.10). The tension of the strap Figure 11.6. Hourly active stabilized IP joint

flexion/extension exercises are performed through the Coban wrap.

Figure 11.7. Intrinsic stretches are performed by holding the MCP joints in the extended position and gently passively flexing the IP joints. This manoeuvre maintains the length of the lateral bands and oblique retinacular ligament.

Accessory ligament

Collateral ligament proper

Ruptured volar plate Joint injuries of the fingers and thumb 137

should be sufficient to provide a gentle stretch without causing pain or restricting circulation. It is left in place for 10 to 15 min every few hours during the day. Resisted exercises and activities are delayed until at least 6 weeks after injury.

Maintenance of home programme

Ligaments are notoriously slow to heal. Persisting pain, stiffness and recurrent joint swelling are common. The patient is therefore encouraged to maintain the exercise and splinting programme for some months following injury. Even when flexion range has been restored, the propensity for recur-rent flexion deformity is great. Intermittent exten-sion splinting by way of a neoprene fingerstall, Capener or static finger splint should be main-tained until the joint no longer ‘relapses’ when

these devices are left off for several consecutive days. Use of the neoprene stall during the day allows unimpeded use of the digit. A Capener or static splint can then be used at night.

Dorsal dislocation of the PIP joint

Dorsal dislocation of the PIP joint is the most common dislocation in the hand. It results from hyperextension of the joint and is usually asso-ciated with a distal rupture of the volar plate from the base of the middle phalanx with or without an avulsed bone fragment (Fig. 11.11).

Figure 11.8. A neoprene fingerstall is the first line of defence in overcoming a PIP joint flexion deformity.

As well as exerting a gentle extension force, the stall will reduce oedema and frequently relieve joint pain.

Active flexion exercises can be carried out with the stall in place.

Figure 11.9. A dynamic Capener splint may be needed to overcome the last 20 to 25 degrees of deformity.

Figure 11.10. Frequent use of an IP joint flexion strap throughout the day will help restore flexion range. The strap can be made from neoprene/velcro, or

alternatively, Coban wrap or Microfoam tape which is shown here.

Figure 11.11. Dorsal dislocation of PIP joint. The collateral ligament proper remains attached and intact and usually provides stability after joint reduction. The accessory portion of the collateral ligament remains with the volar plate which ruptures from the base of the middle phalanx, either on its own or with a small avulsion fragment.

Treatment

The majority of these hyperextension and dorsal dislocations injuries can be reduced satisfactorily and treated conservatively. The PIP joint is splinted in 25 to 30 degrees of flexion for 1 to 2 weeks.

Gentle active exercise is commenced 2 to 3 days after injury when the initial swelling and oedema have subsided. Oedema is managed with Coban wrap. Following removal of the splint, the digit is buddy-strapped to an adjacent finger for support.

Extension splinting is delayed until the 5th week and consists of the same regimen as that which has been described for lateral joint injury.

Unstable fracture-dislocation of