Hemi-hamate arthroplasty for pilon fractures of finger.

BACKGROUND: Injury following proximal interphalangeal joint fracture dislocation is determined by the direction of force transmission and the position of the joint at the time of impact. Dorsal dislocations with palmar lip fractures are the most frequently encountered. The degree of stability is directly determined by the amount of middle phalangeal palmar lip involvement.
MATERIALS AND METHODS: Hemihamate arthroplasty procedure was used in the reconstruction in five cases with comminuted, impacted fractures of the proximal end of middle phalanx of the finger. Three patients were presented within 2 weeks; one patient came by one month and the other by three months following the injury. All patients presented with posterior subluxation of PIP joint.
RESULTS: Functional outcome following this procedure in both acute and chronic cases resulted in adequate restoration of joint stability and function.
CONCLUSIONS: Hemihamate arthroplasty is an adjuvant in the treatment of unstable intra-articular pilon fracture involving PIP joint.

INTRODUCTION

Proximal interphalangeal (PIP) joint injuries are commonly seen in athletes, both amateurs and professionals. The injury is initially considered to be “minor” by either the patient or treated by unnecessarily long immobilisation or surgery, both of which may lead to permanent stiffness or deformity. This bicondylar joint has extreme flexibility and stability throughout its arc of motion, which are difficult to replicate after the joint has experienced injury or degenerative changes.[1] Arthroplasty is a well-established treatment option for the PIP joint that has developed pathological characteristics. We present five cases of osteochondral resurfacing arthroplasty using a portion of hamate bone for comminuted, impacted fractures (pilon fractures) of the proximal end of middle phalanx of the finger.

MATERIALS AND METHODS

We present five cases operated in Sushrutha Institute of Plastic, Reconstructive and Aesthetic surgery, during the period of 2009–2011, with comminuted, unstable palmar lip fractures of middle phalanx with dorsal dislocation or subluxation of the joint. All the injuries were due to axial loading over the fingers due to hit by cricket ball. Three patients who came for treatment within 2 weeks were treated immediately by hemi-hamate arthroplasty procedure. One patient came 1 month and the other by 3 months following injury. Both these patients underwent distraction initially for relaxing the extensor apparatus which had contracted following subluxated position of the PIP joint. Hemi-hamate procedure was done later following adequate distraction.

Indications for hemi-hamate arthroplasty

Comminuted, unstable palmar lip fractures of middle phalanx with dorsal dislocation/subluxation of the joint

Comminuted lateral plateau fracture of the base of middle phalanx

Salvage after failed external fixation, open reduction and internal fixation (ORIF), volar plate arthroplasty (VPA) for complex fracture dislocation of PIP joint

Contraindications for hemi-hamate arthroplasty

Patient inability to comply with postoperative physiotherapy

Associated bone diseases

Substance defect of the base of middle phalanx

Preoperative planning

Acute and subacute injuries present with mild to moderate swelling about the PIP joint. Palmar fracture of the base of the middle phalanx may lead to a clinical deviation and rotational deformity of the digit. Injury may be associated with fracture of distal interphalangeal joint (DIP) joint resulting in bony mallet deformity or a tendinous injury which should be ruled out by clinical examination and radiographic assessment. Range of movement should be measured for both DIP and PIP joints. Anteroposterior and lateral X-rays of the PIP joint are taken. PIP joint subluxation on lateral radiographs present a “V” sign [Figure 1].

Figure 1

X-ray demonstrating the “V” sign due to dorsal subluxation

Surgical technique

A general or regional block anaesthetic is administered. Patient is placed in supine position with the involved extremity supported by a hand table. Brachial tourniquet is applied. The arm is prepared up to the tourniquet level. The first step in the volar approach is a Bruner incision centred over the flexion crease of the PIP joint [Figure 2]. The skin flap is elevated, and care is taken to protect the radial and ulnar digital neurovascular bundles. The flexor tendon sheath is then entered between the A2 and A4 pulleys. As the sheath is entered, it is protected so that it can be repaired at the end of the procedure. A Penrose drain is then placed under the flexor tendons so that they can be retracted either radially or ulnarly to allow for greater visibility of the joint. The proximal aspect of the volar plate is reflected from the proximal phalanx. Care is taken to maintain the volar plate's distal attachment on the middle phalanx. The volar plate will be repaired at closure. The collateral ligaments are then mobilised from the proximal phalanx but are reinserted again at the end of the procedure. At this point, with the volar plate and collateral ligaments released, the joint can be shotgun opened [Figure 3] to expose the particular surfaces. Comminution and depression of the volar middle phalangeal articular base is identified. Joint involvement is estimated from direct intraoperative measurement. Schematic representation of the area of comminuted articular base to be resected is shown in Figure 4. A 4-mm oscillation saw is used to resect the comminuted articular fragments and create a box-like recipient defect. Longitudinal incision is made over the fourth and fifth carpometacarpal (CMC) joints [Figure 5] with mobilisation of dorsal sensory branches of the ulnar nerve. Fourth and fifth CMC joints are exposed between the extensor digitorum communis of the ring finger and the extensor digiti quinti tendons. Schematic diagram shows bifaceted nature of the hamate and graft location [Figure 6]. Measurement and marking of the donor graft is done. Graft is removed [Figure 7]. Fascia and capsule over the CMC joint are closed. Wound is closed in layers. Graft is placed and fixed in position with screws [Figure 8]. After positioning the graft, volar plate is repaired on the lateral side. Tendon sheath is repaired and wound closed in layers. Passive flexion is done after wound closure to confirm the position of the graft.

Figure 2

Bruner type of incision centred over PIP joint

Figure 3

Shotgun opened joint exposing the fracture

Figure 4

Schematic representation of the area of comminuted segment to be removed, (a) PIP joint - Lateral view, (b) PIP joint - Volar view

Figure 5

Longitudinal incision over the fourth and fifth carpometacarpal joints to expose the hamate

Figure 6

Schematic diagram shows bifaceted nature of the hamate and graft location

Figure 7

Fourth and fifth carpometacarpal joints are exposed between the extensor digitorum communis of the ring finger and the extensor digiti quinti tendons to remove the autograft

Figure 8

Schematic diagram for fixation of graft in position with screws (a) PIP joint - volar view, (b) PIP joint - later view

Postoperative management and rehabilitation

Postoperatively, bulky supportive dressing is done with volar splint holding the wrist in 30° of dorsiflexion, with the metacarpophalangeal joints in flexion and the interphalangeal joints in 20° flexion. The part is immobilised for the first 2 weeks. At 10-14 days, the sutures are removed. Flexion movements are allowed. Extension movement is restricted with extension block (30°-40°) for the next 4 weeks. Postoperative radiographs are taken 2 weeks and 6 weeks following surgery. Full mobilisation is started at the end of 6 weeks. Fully unrestricted use is anticipated by 12 weeks.

RESULTS

The mean period of follow-up was 22 months (7–32 months). There was a mean delay of 32 days (14–90 days) between the injury and surgery [Table 1]. All patients presented with posterior subluxation of PIP joint, with the range of movement from 5°–15° associated with pain and loss of grip involving the adjacent fingers. The average range of motion of the PIP joint at final follow-up was 0°–96° (0°–100°). Proper reduction and congruency of the joint was noted on final anteroposterior and lateral radiographs. At final evaluation, no instability of the joints was observed. All patients including the chronic cases presented with pain during movement preoperatively. Except for the immediate postoperative pain, no patients had complaints of pain during mobilisation or movement of fingers after surgery. Average size of the graft used for reconstruction was about 1–1.5 cm in length and 0.5–0.75 cm in breadth. All the grafts united with normal maintenance of joint space without evidence of resorption or degenerative changes. There were no complications at the donor site. There was no functional deficit in the 4th and 5th CMC joint following the procedure.

Table 1

Masterchart representing the list of patients and outcome of hemihamate arthroplasty

CASE REPORTS

Case 1

A 26-year-old male sustained injury to the ring finger while playing. The patient reported after 7 days following injury. He did not have any co-morbidity. Hemi-hamate arthroplasty was done [Figures 9–15].

Figure 9

Preoperative X-ray showing dorsal dislocation

Figure 15

Late postoperative picture showing finger mobilisation

Preoperative clinical picture with swelling and deformity of PIP joint of the left ring finger

Intraoperative picture showing screw fixation of graft

Intraoperative picture showing mobilisation of finger after graft fixation

Immediate postoperative hand picture

Late postoperative X-ray

Case 2

A 29-year-old male sustained injury to the index finger while playing cricket, and he reported after 14 days. He did not have any co-morbid factors. Hemi-hamate arthroplasty was done [Figures 16–19].

Figure 16

Preoperative picture showing deformity and swelling due to dorsal subluxation of left index finger PIP joint

Figure 19

Late postoperative X-ray of the left index finger (a) anteroposterior view (b) lateral view

Postoperative picture of the hand

(a) Late postoperative picture showing finger mobilisation. (b) Late postoperative picture showing finger mobilisation

Case 3

A 32-year-old male who sustained injury to the left middle finger reported after 3 months following injury with no co-morbid factors. The injury was severe in intensity with peri-articular soft tissue contracture. Initially, distraction of the PIP joint was done for 2 weeks and then arthroplasty was done [Figures 20–27].

Figure 20

Preoperative picture showing deformity of the finger due to pilon fracture of the left middle finger

Figure 27

Preoperative picture and plan of incision

Preoperative picture showing the deformity in the left middle finger–volar view

X-ray showing the deformity of the left middle finger

C-arm X-ray view following distraction for 2 weeks with Joshi's External stabilization System

Intraoperative picture showing fixation of graft by screws

Intraoperative picture showing joint mobilisation following arthroplasty

C-arm X-ray picture showing the position of hemi-hamate graft and joint congruity

DISCUSSION

Fracture dislocation of the PIP joint of the hand, although relatively uncommon, is a potentially disabling injury which leads to persistent pain and stiffness.[2-4] The management of intra-articular fractures of the PIP joint is a therapeutic problem.[5] Multiple systems of categorising this injury exist. We used the classification devised by Joseph J. Dias et al.[6] Descriptions of type of classification used in the treatment section are represented in schematic diagram [Figure 28]. Unstable palmar lip fractures involve greater than 50% of the palmar articular surface of the middle phalanx base and those involving 30–50% require more than 30° of flexion to maintain concentric reduction of the PIP joint. Treatment is aimed at restoring or stabilising the cup-shaped geometry of the base of the middle phalanx by reconstructing its palmar deficiency, which is responsible for the instability of these fractures. Slades et al.[7] used a dynamic distraction external fixator device for the unstable fracture of PIP joint in 26 patients. This procedure relies on ligamentotaxis for indirect fracture reduction which requires a pin that can be problematic from an infection or functional point of view. Dynamic distraction procedure has been viewed as a less invasive treatment option, but its effectiveness on reduction of joint and aligning the depressed fracture fragments remains doubtful.

Figure 28

Schematic diagram showing classification of fracture dislocation of interphalangeal joint

Two unique methods have been designed for the treatment of unstable palmar lip fractures: Palmar plate arthroplasty and hamate osteochondral autograft arthroplasty. Described by Eaton and Malerich,[8] VPA involves advancement of the palmar plate into the defect at the base of the middle phalanx to resurface the damaged articular surface and to restrain dorsal subluxation of the joint.[8] The procedure and useful modifications have been well described in the literature.[8-10] Complications of VPA include recurrent subluxation, inadequate PIP motion, and DIP joint stiffness. For the management of severe dorsal PIP fracture dislocations, the hemi-hamate arthroplasty has several advantages over alternative treatments. Comminuted articular fractures prohibit, or at least increase, the technical difficulty of open reduction and internal fixation.[1112] VPA is less reliable for fractures involving over 50% of the base of the middle phalanx.[813] External fixation, which relies on ligamentotaxis for indirect fracture reduction, is most effective acutely and requires pins that can be problematic from an infection or functional standpoint. Patient with single fragment fractures amenable to internal fixation were not offered hemi-hamate reconstruction and are believed to be a population expected to recover with minimal disability. With increased number of fracture fragments, ORIF may restore motion similar to hemi-hamate reconstruction. The surgeon must decide whether the fragment size is sufficient for reliable fixation or if debridement and placement of a hamate autograft would be technically more feasible. Patients presenting with more complex fracture patterns are offered VPA when the fractures involve less than 50% of the joint surface. Hemi-hamate arthroplasty is recommended for fractures involving over half of the joint surface on the basis of our perceived risk of recurrent instability with VPA. The results of hemi-hamate reconstructions for severe dorsal PIP joint fracture dislocations are promising. In chronic cases, distraction was initially done for relaxing the extensor apparatus which had contracted following subluxated position of the PIP joint. In chronic cases, we allowed distraction at least for 2 weeks till adequate joint space was obtained. Hemi-hamate procedure was done later following adequate distraction.

Ellis et al.[14] reported four patients with fractures of 50% of the articular surface that regained 88° of PIP motion with external fixation. Hastings et al.[15] reported five patients who were treated with hemi-hamate arthroplasty and recovered 77° of PIP motion at 10 months postoperatively. Williams et al.[16] subsequently published results of 13 reconstructions at a mean of 16 months with recovery of 85° of PIP motion. In our series, we regained approximately 0°-96° of PIP joint range of motion even in chronic cases. Restoration of PIP motion was similar between chronic and acute reconstruction which was comparable to the outcome achieved by Stern et al.[17] However, a large number of patients will need to be examined serially over time to validate the long durability of this reconstruction. Hemi-hamate arthroplasty may be considered as the treatment of choice for acute and chronic PIP joint fracture dislocations involving at least 50% of the volar articular surface, which are not amenable to primary internal fixation.

CONCLUSIONS

Hemi-hamate resurfacing arthroplasty procedure is definitely a useful adjuvant in the treatment of Type 4 unstable intra-articular pilon fractures of middle phalanx involving PIP joint. In late cases, distraction of the peri-articular soft tissue should be done to avoid redislocation.