Pilon fractures of the proximal interphalangeal joint A pilon fracture is an uncommon intraarticular fracture of the proximal interphalangeal (PIP) joint resulting in comminution, central depres sion, and splay, sagittally and coronally, of the articular surface of the base of the middle phalanx. This study reviews three treatment methods and results in 20 patients. Injury was produced by an axial load and occurred primarily to the ulnar digits. Clinical and radiographic follow-up averaged 25 months. Treatment was divided into three categories: splint (four patients), skeletal traction through the middle phalanx (seven patients), and open reduction with Kirschner pins (nine patients). Anatomic restoration of PIP articular contour was not achieved, regardless of technique. No patient regained full mobility at either interphalangeal joint. Treatment by immobilization is undesirable. Open reduction should be approached cautiously and may result in significant complications. Skeletal traction is safe and gives result s that are radiographically and clinically comparable to those achieved with open reduction. (J HArm SURG 1991;16A:844-50.)

Peter J. Stern , MD, Robert J. Roman, MD, Thomas R. Kiefhaber, MD, and John J. McDonough, MD, Cincinnati, Ohio

Derived from the Latin word pilum (a "pounder"), a pilon fracture of the proximal interphalangeal (PIP) joint is defined as an axial loading injury resulting in comminution, central depression, and splay , sagittally and coronally, of the articular surface of the base of the middle phalanx . Pilon fractures are rare injuries. In a series .of intraarticular PIP fractures reported by Hastings and Carroll, 1 there were three such injuries out of 110 fractures of the base of the middle phalanx. These injuries pose a therapeutic problem in terms of aggressiveness of treatment and interval of immobilization. Pain, subluxation, degenerative arthritis, stiffness, and PIP flexion contracture can all be sequelae of pilon fractures. Multiple reports have been published on the treatment of intraarticular PIP fractures and dislocations, including immobilization in an advanced degree of flexion ,2. 3 open reduction.':"extension From the Department of Orthopaedic Surgery and Hand Surgery Consultants, University of Cincinnati College of Medicine, Cincinnati, Ohio . Received for publication April 18, 1990; accepted in revised form Nov. 23, 1990, No benefits in any form have been received or will be received from a commer cial party related directly or indirectly to the subject of this article. Reprint requests: Peter J. Stem , MD, Cincinnati Hand Surgery Consultants , Inc., 2800 Winslow Ave,. Suite 401 , Cincinnati. Ohio 45206 .

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block splinting," dynamic force couple," palmar plate arthroplasty," silicone spacer;'? and tridirectional traction in a banjo frame. II . 12 To our knowledge, there is little documentation of injuries with this definition. We review our experience with three therapeutic methodssplint , skeletal traction , and open reduction-and assess the long-term results.

Materials and methods Twenty patients with closed pilon fractures of the PIP joint were reviewed. The average age was 31 years (range, 17 to 44 years). There were 16 male and 4 female patients. The mechanisms of injury included strike by a ball (13), trauma related to occupation (4), fall (2), and assault (1). Of these injurie s, there were 12 to the small finger, 5 to the ring finger, and 3 to the long finger. The average time from injury to treatment was 2 days (range, 0 to 21 days) , and average interval to follow -up was 25 months (range, 7 to 60 months). The three categories of treatment included splint (four patients), skeletal traction (seven patients), and open reduction (nine patients). Splinting was achieved with a dorsal splint immobilizing the PIP joint in 30 to 45 degrees of flexion. Patients placed in traction were anesthetized with a metacarpal block. A pin was then placed through the diaphysis of the middle phalanx, and axial traction was applied by either banjo traction ll • 12 (six patients) or Schenck traction" (one patient) . In two cases (patients J. M. and R. P.) banjo

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Fig. 1. Skeletal traction. A and B, Anteroposterior and lateral x-ray films of a pilon fracture of the small finger. C and D, Anteroposterior and lateral x-ray films after 7 days of skeletal traction. Note correction of the palmar subluxation but persistent displacement of the dorsal fragment. E and F, Anteroposterior and lateral x-ray films 21 months after injury showing consolidation of the fracture fragments and articular remodeling. G and H, Follow-up shows excellent flexion. However, there is persistent PIP swelling and loss of extension.

Table I. Splint

PI R.M. M. S. L. A.

P.l. Average

Follow-up .(mo) Age Sex

38 24 38 30

F M M F

13 12 26 36

Digit L R R L

ring small small long

Duration of Dominant lnjury-trtmt immobilization (wk} hand (days) R R R R

0 0 0

1 0

6 4 4 5 5

'Grip strength measured with a dynamometer by an average of three trials on a selling of 2. tPain defined as: 0 = pain-free; 1 = pain with axial loading; 2 = pain with heavy activity; 3

Actiw range of motion PIP

I

DIP

Grip strength (lb)*

I

Injured Noninjured Paint

10190 10160 30185 0/55 20190 5/60

= continuous pain.

58 121

90

69 108

80

2 3 3 3 3

Additional treatment

Arthrodesis Arthrodesis

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Table II. Skeletal traction

Pt

Age

Sex

J. D. R. P. J. M. B. B. J. A. J. E. J. R. Average

25

33 35 37 17 27 27

M M M M M M M

Follow-up (mo)

13 43

21 12 24 45

10

Digit

Dominant hand

Injury-trtmt (days)

R small R small R small L small L small L long L small

R R R R R R R

3

Early ROM (days)

4

3 I 3

o o

2 7

3

I I 2.5

o

o I

AROM = Active range of motion; CPM = continuous passive motion. 'Grip strength measured with a dynamometer by an average of three trials on a setting of 2. tPain defined as: 0 = pain-free; I = pain with axialloadin.g; 2 = pain with heavy activity; 3

Duration of traction (wk)

3 4 3 3 3 4 6 4

= continuous pain.

Table III. Open reduction

Digit

Dominant hand

lnjury-trtmt (days)

Duration of immobilization

Pt

Age

Sex

Follow·up (mo)

A.Q.

26

M

52

L ring

L

S. E. M.G. R. H. G.F.

27 30 33

7 18 22 12

L ring R small R small L long

R R L R

0 2 2 2

4 4 4

44

M M F M

N. S. N. R. D. P.

31 38 36

F M M

12 28 30

L small L ring L ring

R R R

2 2 0

2

M.H. Average

20 32

M

60 27

R small

R

= Active range of motion. 'Grip strength measured with a dynamometer by an average of three trials on a setting of 2. tPain defined as: 0 = pain-free; I = pain with axial loading; 2 = pain with heavy activity; 3

[wk}

4

4

5

4 4

ARO~1

traction was combined with continuous passive motion. Open reduction was achieved predominantly by a dorsal approach (six patients) with one midaxial approach. Stabilization was uniformly achieved by means of both Kirschner pins (eight patients) and, in the case of patient A. Q., Kirschner pins combined with external fixation. Bone graft was not used. In no case was anatomic restoration achieved at the time of surgery. Results The long-term results were judged on range of motion, grip strength, pain, swelling, radiographic ap-

= continuous pain.

pearance, and complications. Patients were evaluated by R. J. R., who was not responsible for patient management. Splint (Table I). Splinting averaged 5 weeks (range, 4 to 6 weeks). At follow-up, active range of PIP joint motion was 20/85 and range of DIP joint motion was 5/55. In two patients symptomatic PIP arthritis developed, necessitating surgical arthrodesis. Of the other two patients, one had continuous pain and the other had pain with heavy activity. In addition, both patients had symptomatic PIP swelling and limitation of PIP and distal interphalangeal (DIP) motion. Radiographs

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Pilon fractures of proximal interphalangealjoint

Grip strength (lb)*

AROM PIP

I

0/90 0/80 40/90 25/90 0/90 0/90 20/90 10/90

DIP

Injured

0/80 5/25 0175

I

I

Noninjured

Paint

0110

115 127 85 120

125 118 106 130

0170 0/45 0140 0/50

101 110

105 115

I I 0 0 0 0 2 I

I

DIP

Injured

35170

10110

93

107

0/50 0175 0/60

5170 5150 0/30

90

101

61

61

0/95 10/95 0/90

Traction type Banjo traction Banjo traction + CPM Banjo traction + CPM Schenck traction 12 Banjo traction Banjo traction Banjo traction

Grip strength [lb]"

AROM PIP

847

10170

0/60 0/60

15/90

0165

10/80

5150

Non-injured

Paint

Internal and external fixationPIP pyarthrosis at 3 weeks of immobilization 3 I I 3

55 98 75

70 107 95

I 0 2

79

90

0 I

at follow-up showed articular remodeling with varying degrees of central depression and splaying. Skeletal traction (Table II, Fig. 1). The average duration of traction was 4 weeks (range, 3 to 6 weeks), with active range of motion initiated 2Y2 days after being placed in traction (range, 1 to 7 days). Average range of motion at follow-up was 10/90 at the PIP joint (range, 40/90 to 0/90) and 0/50 at the DIP joint (range, 0110 to 0/80). No patient had subsequent surgery. At follow-up, patients achieved symmetric grip strength, and all patients had some degree of fusiform PIP swelling. Follow-up radiographs showed remodeling of the

Complications and associated injuries

Fell on pin l'h weeks after ORIF; arthrodesis

Left index finger: avulsion of ulnar collateral ligament of MP joint

base of the middle phalanx and varying degrees of splay, both sagittally and coronally, of the base of the middle phalanx. At follow-up, four patients reported no pain, two had pain with axial loading, and one had pain with heavy activity. Open reduction (Table Ill, Fig. 2). Duration of immobilization with Kirschner pins averaged 4 weeks (range, 2 to 5 weeks). Open reduction resulted in seven satisfactory outcomes, with an average range of motion at follow-up of 10/80 at the PIP joint (range, 0/50 to 0/90) and 5/55 at the DIP joint (range, 0/30 to 5/65). In the two unsatisfactory outcomes, patient A. Q. had

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Fig. 2. A and B, Anteroposterior and lateral x-ray films of a pilon fracture of the ring finger treated by both open reduction and internal and external fixation. C, Intraoperative anteroposterior x-ray film in external fixation. Despite the surgeon's best effort , articular congruity was not restored. D, Intraoperative photograph showing external fixation and Kirschner pins. E, Three weeks later, pyarthrosis necessitated removal of the external fixation, incision and drainage, arid a skin graft.

a PIP pyarthrosis after 3 weeks of immobilization, requiring removal of an external fixation device, open drainage, and skin grafting, and patient G. F. fell after I Y2 weeks of immobilization and sheared off the Kirschner pin, which resulted in a loss of reduction and necessitated later PIP arthrodesis, At follow-up, patients had achieved symmetric grip strength, and all had mild PIP swelling. Follow-up x-ray films all showed a lack of anatomic articular restoration and significant remodeling of the articular surface of the base of the middle phalanx. Two were pain free , four had pain with axial loading, one had pain with heavy activity, and two had continuous pain.

Discussion Management of comminuted intrarticular fractures of the base of the middle phalanx poses a therapeutic dilemma. Ideally, one should strive for anatomic restoration of the joint contour and early range of motion to minimize posttraumatic arthritis and stiffness. In reality, however, this goal may be impossible because of excessive intraarticular and subchondral comminution. We found treatment by immobilization undesirable. The inadequacy of this treatment is supported by the results achieved in this study as well as other published reports, which note that articular cartilage has a limited healing and regenerative ability. 13 Immobilization of the

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Fig. 2 (Cont'd). F and G, X-ray films 4 years later depicting articular remodeling. II and I, Range of motion 4 years later. Note satisfactory PIP motion but loss of DIP flexion.

PIP joint interferes with the normal mechanisms of synovial fluid transport (by intermittent compression of the cartilage), which brings in nutrients and diffuses away waste products.'>" Furthermore, reports have shown evidence of degenerative changes in articular cartilage with lack of normal movement. 13. 16 Of interest was the articular remodeling of the base of the middle phalanx. Eaton and Malerich? also noted remodeling of the disrupted joint contour after palmar plate arthroplasty but raised concerns about articular resurfacing when traction was employed. Comparison of the x-ray films of traction versus open reduction in this study showed equivalent remodeling of the articular surface; statistical analysis of the range of motion showed no significant difference (p > 0.13), leading to the conclusion that traction and open reduction will result in similar outcomes.

In our patients, we were unable to achieve anatomic restoration of these complex intraarticular fractures through open reduction. Furthermore, we were unable to achieve rigid fixation, and this necessitated postoperative immobilization for an average of 4 weeks. However, better results might be obtained through improved surgical techniques, including bone grafting and earlier mobilization. I. 18 Considering the risks of internal fixation, traction is a reasonable alternative and, when combined with motion, has the biologic advantage of cartilage and soft tissue nutrition. 12·14. 16. 17 In conclusion, regardless of the treatment, patients had mild limitation of PIP and DIP motion. Splint immobilization is not recommended. Open reduction should be approached cautiously; with this modality, anatomic restoration may be impossible and even unnecessary. Skeletal traction is safe and gives results that

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Stern et al.

are radiographically and clinically comparable to those achieved with open reduction.

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10. Swanson AB, Maupin BK, Gajjar NV, Swanson G. Flexible implant arthroplasty in the proximal interphalangeal joint of the hand. J HAND SURG 1985;IOA:796805. 11. Robertson RC, Cowley JJ, Faris AM. Treatment of fracture-dislocation of the interphalangeal joints of the hand. J Bone Joint Surg 1946;28:68-70. 12. Schenck RR. Dynamic traction and early passive movement for fractures of the proximal interphalangeal joint. J HAND SURG 1986;l1A:850-8. 13. Salter RB, Simmonds DF:, Malcolm BW, Rumble EJ, Macmichael D, Clements ND. The biologic effect of continuous passive motion on the healing of full-thickness defects in articular cartilage. J Bone Joint Surg 1980;62A: 1232-51. 14. Salter RB, Bell RS, Keeley FW. The protective effect of continuous passive motion on living articular cartilage in acute septic arthritis: an experimental investigation in the rabbit. Clin Orthop 1981;159:223-47. 15. Trias A. Effect of persistent pressure on articular cartilage. J Bone Joint Surg 1961;43B:376-86. 16. Salter RB. Presidential address, Canadian Orthopaedic Association, Halifax, N.S. J Bone Joint Surg 1982;64B:251-4. 17. Frank C, Akeson WH, Woo SL-Y, Arnie! D, Coutts RD. Physiology and therapeutic value of passive joint motion. Clin Orthop 1984;185:113-23. 18. Heim U, Preiffer KM, et al. Internal fixation of small fractures: technique recommended by AO-ASIF group. 3rd ed. New York: Springer-Verlag, 1988:207-8.