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Trapezoid rotational bone graft osteotomy for metacarpal and phalangeal fracture malunion
ARTICLE IN PRESS TRAPEZOID ROTATIONAL BONE GRAFT OSTEOTOMY FOR METACARPAL AND PHALANGEAL FRACTURE MALUNION F. C. YONG, S. H. TAN, B. P. B. TOW and L. C. TEOH From the Department of Hand Surgery, Singapore General Hospital, Outram Road, Singapore
Metacarpal and phalangeal fracture malunions with significant angulation deformity are associated with bone shortening, prominence of the metacarpal head in the palm or pseudoclaw deformity and may be symptomatic. If so, they may need corrective osteotomy procedures. Conventional methods of closing, or opening, wedge osteotomy do not restore the length of the bone exactly. Simultaneous correction of the angular deformity and restoration of bone length can be addressed by a trapezoid rotational bone graft osteotomy. A double osteotomy is done and the segment of bone is rotated and re-inserted as a bone graft. This was done successfully in four metacarpal and two phalangeal fracture malunions with angulation deformities. Journal of Hand Surgery (European Volume, 2007) 32E: 3: 282–288 Keywords: metacarpal phalangeal malunion, trapezoid osteotomy
Malunion of metacarpal fractures with dorsal angulation deformity may result in significant metacarpal shortening and/or prominence of the metacarpal head in the distal palm. Proximal phalangeal fracture malunion with volar angulation deformity may result in bone shortening, pseudoclaw deformity and decrease in range of motion of the joints of the finger. Both of these malunions may result in painful hand grasp and/or decreased grip strength. These problems are usually experienced when the angle in the metacarpal shaft is greater than 301 or the shortening is greater than 2 to 5 mm and when the angle is greater than 25 to 301 in the proximal phalanx (Green, 1986; Lee and Jupiter, 2000; Stern, 2005; Wolfe and Elliot, 1996). Correction of these angular deformities has previously been achieved by either a closing wedge or an opening wedge osteotomy at the fracture site. However, these procedures do not restore the length of the bone to its initial pre-fracture length. In a closing wedge osteotomy of 301 or greater, there may be significant shortening in the length of the bone as a result of removal of the wedge of bone (Fig 1). The geometrical gain in length by straightening the bone is, to some extent, negated by this shortening. In an opening wedge osteotomy, there is lengthening of the bone, resulting in an over-correction of bone length (Fig 2). The latter procedure also involves harvesting a bone graft from a distant site, with the inherent risk of donor site morbidity (Cockin, 1971). Stabilisation of the bone graft can also be difficult. Restoration of the bone length, whilst correcting the angular deformity, can be addressed by the trapezoid rotational bone graft osteotomy technique (Fig 3), the use of which is illustrated in five patients in this study.
motion of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. Their pre-operative malunion angles averaged 381 (range 321–451). Another two patients with two proximal phalangeal fracture malunions with volar angulation of the little fingers had pseudoclaw deformities. One of them complained of having decreased grip strength and the other of painful grasp function. The former had decreased range of motion of the MCP joint and the latter had decreased range of motion of the PIP joint. In addition, the former patient had a volar subluxation of the proximal phalanx at the MCP joint. This may have occurred following two previous attempted operations to correct the deformity in his right little finger. He had sustained the injury to his little finger more than ten years earlier and the last operation was approximately five years ago. Their preoperative malunion angles were 601 and 501, respectively. All five patients were men of average age 32.5 (range 20–51) years (Table 1). Corrective osteotomies, as described below, were carried out to the metacarpals and phalanges at the sites of angulation. Surgical technique for metacarpal dorsal angulation (Figs 3 and 4) Pre-operatively, the angle of deformity a1 is measured on the lateral view radiograph of the metacarpal. The operative angle of osteotomy is then calculated. In a closing wedge osteotomy, the osteotomy is performed at two sites, proximal and distal to the apex of the dorsal angulation, at an angle perpendicular to the bone such that they meet at the far cortex and each osteotomy corrects 12a : In our procedure, the osteotomies are done further apart to cut out a trapezoid segment of bone and the angle of osteotomy from the perpendicular to the bone should be 14a ; as this segment of bone is removed, rotated and re-inserted as a free bone graft. The two
PATIENTS AND METHOD Three patients with four metacarpal fracture malunions with dorsal angulation presented with painful hand grasp function, although they had normal ranges of 282
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283
Fig 1 Closing wedge osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). Wedge osteotomy of a1 is as shown and (C) if a wedge of bone is removed, angulation is corrected but bone lengthening, as shown by (b), falls short of the correct and full length.
Fig 3 Trapezoid rotational bone graft osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). An osteotomy at 14a to the perpendicular to the bone is done at two sites to create a trapezoid bone segment, (C) the segment of bone is removed, rotated and re-inserted as shown in (D) then stabilised with a metal plate and screws. The bone length (b) is restored to its initial length.
Fig 2 Opening wedge osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). Perpendicular osteotomy is done at the apex of the angulation of the bone and (C) if an opening ‘‘wedge’’ osteotomy is done and a bone graft inserted, the lengthening (b) obtained is overlong compared to the initial bone length.
sites of the osteotomy are placed at a distance apart such that the shorter cortex of this trapezoid segment of bone is of a sufficient length for the stable placement of a screw, i.e. three times the diameter of the screw-being used. For example, if the diameter of the screw is 1.5 mm, then this cortex length should be at least 4.5 mm. The fixation of the corrective osteotomy is by metal plate and screw internal fixation. A 1.5 mm or
2.0 mm mini-plate may be used, depending on the size of the bone and the surgeon’s choice. A straight plate is used for the metacarpal bone and should be, at least, a six-hole plate. The malunited fracture site is exposed from a dorsal approach. The trapezoid segment of bone is marked out for osteotomy, as described above, such that the palmar cortex will be at least three times the diameter of the metal screws which will be used later for internal fixation of the bone. The angle of osteotomy is measured from the perpendicular to the bone towards the angle of the deformity, proximally and distally (Fig 3B). Placing a K-wire perpendicular to the axis of the bone may facilitate this marking process. Following the osteotomy, the trapezoid segment of bone is removed, rotated 180o% and re-inserted as an interposition bone graft (Fig 3C and D). The bone segments are aligned, reduced and internally fixed with a compression metal plate and screws (Fig 3D).
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Table 1—Patient details pre- and postsurgery Case
Sex
Age (years)
1
M
20
2
M
20
3
M
22
4
M
48
5
M
51
Bone involved
Angulation
Symptoms
Pre-op (degrees)
Post-op (degrees)
Pre-op
Right 5th MC Left 4th MC Left 5th MC Right 5th MC Right little PP
45
0
32
0
Painful grip Painful grip
35
0
40
0
60
15
Right little PP
50
0
Painful grip Pseudoclaw, weak Pseudoclaw, Painful grip
Grip strength (kg force)
Post-op Pre-op (R/L) No pain No Pain
No pain No claw, strong grip No claw, no pain
ROM (MCPj/PIPj)
Bone union (months) Prox/ distal
Post-op (R/L)
Pre-op
Post-op
–
–
Full ROM
Full ROM
3/3
38/40
38/43
Full ROM
Full ROM
4/4
Full ROM
Full ROM
4/4
–
–
-
FROM
4/8
35/45
43/48
601/1001 subluxed MCPJ
801/1001 no subluxed MCPJ
3/3
–
33/36
901/601
901/851
6/4
MC: metacarpal; PP: proximal phalanx; MCPj: metacarpophalangeal joint; PIPj: proximal interphalangeal joint; ROM: range of motion.
The centre screw to the bone graft segment is placed first, followed by compression fixation to the proximal segment with an eccentrically placed screw. This is repeated for compression fixation of the distal bone segment to the middle bone graft segment. The alignment of the reduction and the fingers are checked and confirmed. The remaining screws are then inserted in neutral positions. This procedure restores the bone to its initial pre-fracture length whilst correcting the angulation deformity: no bone is removed or added. Stable ‘‘rigid’’ bone fixation with a mini-plate and screws allows immediate postoperative mobilisation. Surgical technique for proximal phalangeal volar angulation (Fig 5) Similar pre-operative measurements are done. The proximal phalanx is exposed through a dorsal skin incision and the extensor tendon split. Commonly, the fracture malunion site is at the base of the phalanx and the proximal osteotomy site is placed such that there is sufficient length of bone proximally for placement of the transverse arm of the T-plate, which will be used for internal fixation of the bone. Since the apex of the angulation deformity is volar and the surgical approach is dorsal, the angle of osteotomy from the perpendicular to the bone is measured away from the angle of the deformity. Otherwise, the procedure is similar to that for the metacarpal, described above, except that a T-plate and screws are used for stable bone fixation.
The longitudinal arm of the plate should have at least four-holes. Care should be taken when using the power saw for the osteotomy of the proximal phalanx as the flexor tendon lies in a shallow trough on the volar surface of the bone. The flexor tendon was partially cut in case 4 (Table 1) and required repair primarily. He subsequently required flexor tendon rehabilitation incorporated into the post-operative therapy programme. An osteotome was used for completion of the osteotomy in case 5 to avoid this problem. Active and passive joint mobilisation therapy commences on the first postoperative day. It has been our experience that patients will mobilise only the joints that are painless on mobilising through the full range of motion. Thus, therapy is focused on the joints that are expected to be painful with full range of motion. This frequently occurs at the MCP joint in metacarpal fractures and at both the MCP and PIP joints in phalangeal fractures. After the proximal phalangeal osteotomy, a PIP joint extension splint is used between exercise sessions if full active extension is not achieved by two weeks after surgery, to help prevent PIP joint volar plate contracture. The ranges of motion at the MCP and PIP joints were measured at one week and, thereafter, monthly until fracture union was seen on X-rays of the osteotomy. Grip strength was measured at grip position 2 of a Jamar dynamometer (TEC, New Jersey 07012, USA). Radiographs of the metacarpals or phalanges were done postoperatively and at six weeks, three months and,
ARTICLE IN PRESS TRAPEZOID ROTATIONAL BONE GRAFT OSTEOTOMY
thereafter, monthly to confirm retention of the correction and assess bony union.
RESULTS Radiographic illustration of case 1, with malunion of the fifth metacarpal, is shown in Fig 4. The angle of deformity is measured in the lateral view (Fig 4A). The trapezoid shaped rotational bone graft is about the optimal size for placement of one screw i.e. the shorter cortex is about 4.5 mm long which is three times the diameter of the 1.5 mm screw used (Fig 4B and C).
285
Radiographic illustration of cases 2, with fourth and fifth metacarpal malunions, and 5, with proximal phalanx malunion in the little finger, are shown in Figs 5 and 6, respectively. Table 1 shows the details of measurements pre- and postoperatively. The angulation deformities were fully corrected in all the metacarpals and one proximal phalanx and 75% corrected in the other proximal phalanx, which had the largest angle of deformity. The postoperative periods were uneventful. Bone union was achieved by three to four months, except for the proximal interface of the bone graft in case 3 and the distal interface in case 5. These achieved bone
Fig 4 X-rays of malunion of the right fifth metacarpal in case 1: (A) illustration of a 451 angular deformity of the fifth metacarpal on lateral and posteroanterior X-ray views, (B) illustration of stable fixation of the trapezoid bone graft with a plate and screws on a posteroanterior X-ray view and (C) illustration of early union of the bone graft osteotomy on an oblique X-ray view.
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Fig 5 X-rays of malunions of the right fourth and fifth metacarpals in case 2: (A) pre-operative posteroanterior and lateral X-rays illustrating the metacarpal malunions and (B) posteroanterior and lateral X-rays taken at four months, illustrating consolidated bone union of the osteotomies.
union on X-ray at eight and six months, respectively. Considering that this is a bone grafting procedure, we consider bony union at four months to be acceptable. Thus, there was delayed union in 2 out of the 12 of the osteotomy sites, or interfaces of the cortical bone grafts. All of the patients, except case 1, had removal of the implants carried out at seven months to one and a half years after surgery. There were no cases of re-fracture after removal of the implants. Painful grasp was completely relieved in all the cases. The pseudoclaw deformities were corrected in the two
cases with proximal phalangeal malunion. The MCP joint ranges of motion were all maintained at the pre-operative full range of motion. The PIP joint ranges of motion for the cases of proximal phalangeal malunion improved by 201 and 251, respectively. However, they remained short of the normal range by 101 and 151, respectively. Grip strength improved post-operatively in the two cases who had comparative measurements done pre-operatively. Case 4 who suffered an accidental partial cut flexor tendon did not have any complications arising from it and there were no trophic or sensory problems.
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Fig 6 Clinical photographs and X-rays of malunion of the right little finger proximal phalanx in case 5: (A) illustration of the pseudoclaw deformity of the little finger, (B) the deformity is partially corrected postoperatively, although an extension lag at the PIP joint remains, (C) posteroanterior and lateral X-rays showing the malunion of proximal phalanx of the little finger and (D) postoperative posteroanterior and lateral X-rays showing the correction of the malunion, bone union at the proximal osteotomy site and delayed bone union at the distal osteotomy site.
DISCUSSION The common deformity seen in metacarpal shaft fracture malunion is dorsal angulation. In proximal phalanx basal fracture malunion, this volar angulation. These result in shortening of the bone (Fig 1A and B). The metacarpal head may be prominent in the palm, causing discomfort on gripping, and the MCP joint centre of rotation moves more palmar in relation to the intrinsic muscles. A pseudoclaw deformity commonly occurs in angulated fractures of the base of proximal phalanx (Fig 6A). The shortening is greater when the angulation occurs towards the midshaft of the bone. The metacarpal head is more prominent in the palm in distal metacarpal shaft angulation (Wolfe and Elliot, 1996). These factors contribute to the symptoms of painful grasp and decreased grip strength (Seitz and Froimson,
1988; Stern, 2005; Wolfe and Elliot, 1996). Gropper and Bowen (1984) reported their indications for open reduction and internal fixation of acute metacarpal fractures, which included shortening of more than 2 mm and dorsal angulation of 251 in the fourth metacarpal and 30o% in the fifth metacarpal. Most authors report that metacarpal malunion is acceptable if the resultant bone shortening is not greater than 2 to 5 mm and angulation not greater than 201 to 301 (Burkhalter, 1990; Green, 1986; Lee and Jupiter, 2000; Wolfe and Elliot, 1996). In the presence of symptomatic metacarpal and phalangeal shaft fracture malunion with angulation deformity, the surgical procedure should correct the angle of deformity and restore the length of the bone. Correction of the angle of deformity can be achieved by the conventional methods of either a closing, or an opening, wedge osteotomy at the fracture site (Seitz and
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Froimson, 1988). However, neither of these procedures restores the length of the bone exactly. In opening wedge osteotomy, there is a significant lengthening of the bone, resulting in an over correction of bone length (Fig 2). It also involves harvesting a bone graft from a distant site, with the inherent risk of donor site morbidity (Cockin, 1971). Stabilisation of the bone graft may also be difficult. In a closing wedge osteotomy of 301, or greater, there is significant shortening in the length of the bone as a result of the removal of the wedge of bone (Fig 1). Wolfe and Elliot (1996) reported that this dorsal length loss is usually offset by the geometrical length gain achieved by the angular correction. However, this geometrical length gain only offsets the original geometrical length loss resulting from the initial fracture with angulation deformity. It is insufficient to compensate for the additional length of bone loss contributed by the closing wedge osteotomy. The wedge of bone could simply be rotated through 180o% and then re-inserted as a free bone graft. If this is done, the angle of osteotomy should be halved (Yong et al., 2000). However, it is difficult to achieve a stable fixation of the small wedge of bone with the angled edge at the near cortex. If the osteotomy is done similarly at two sites, but further apart, to get a trapezoid block of bone with sufficient length for placement of a screw in a stable plate and screws fixation construct, fixation is easier and more stable. In this reconstruction, the angle of osteotomy will need to be further halved, i.e. onequarter of the angle of deformity (Fig 3). The smaller angle of osteotomy also facilitates a compression fixation technique to enhance bone union. A metal plate and screw compression fixation is recommended for maximum stable internal fixation of the osteotomy (Black et al., 1985). It also enables immediate postoperative joint mobilisation. The osteotomy is done at the site of malunion and no bone is removed, or added. Therefore, it restores bone length to its initial, prefracture length, whilst correcting the angle of deformity. Our patients had metacarpal shaft angular deformities of 321 to 451 and proximal phalanx basal angular deformities of 501 to 601. There were no problems at surgery to correct these angulations except in one case, that with a 601 angulation at the base of the proximal phalanx, which only achieved 75% correction. Four out of five of the patients had symptoms of pain on grasp function. These all resolved and none showed deterioration of their symptoms. Grip strength also improved in the patient who complained of weak grip. Delay of
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union might be considered a complication of this trapezoid osteotomy procedure as this occurred in two of the 12 osteotomy sites. To minimise the likelihood of this occurring, or this having any ill effects, compression plate and screw bone fixation is recommended for this procedure. In this small series, there were no problems at surgery or with ultimate bony union of the resultant free cortical bone graft. Correction of the angular deformity and precise restoration of the metacarpal and phalangeal bone length are possible using this technique and should contribute to pain relief and improvement in grip strength. References Black D, Mann RJ, Constine R, Daniels AU (1985). Comparison of internal fixation techniques in metacarpal fractures. Journal of Hand Surgery, 10A: 466–472. Burkhalter WE. Hand fractures. In: Greene WB (Ed) Instructional course lectures. Chicago, AAOS, 1990, Vol. 39: 249–253. Cockin J (1971). Autologous bone grafting – complications at the donor site. Proceedings and reports of councils and associations. Journal of Bone and Joint Surgery, 53B: 153. Green DP (1986). Complications of phalangeal and metacarpal fractures. Hand Clinics, 2: 307–328. Gropper PT, Bowen V (1984). Cerclage wiring of metacarpal fractures. Clinical Orthopaedics and Related Research, 188: 203–207. Lee SG, Jupiter JB (2000). Phalangeal and metacarpal fractures of the hand. Hand Clinics, 16: 323–332. Seitz WH, Froimson AI (1988). Management of malunited fractures of the metacarpal and phalangeal shafts. Hand Clinics, 4: 529–536. Stern PJ. Fractures of the metacarpals and phalanges. In: Green DP, Hotchkiss RN, Pederson WC, Wolfe SW (Eds) Green’s operative hand surgery, 5th Edn. Philadelphia, Churchill Livingstone, 2005, Vol. 1: 297–299 and 324–327. Wolfe SW, Elliot AJ. Metacarpal and carpometacarpal trauma. In: Peimer CA (Ed). Surgery of the hand and upper extremity, New York, McGraw-Hill, 1996, Vol. 1: 883–920. Yong FC, Teoh LC, Liau KH (2000). A new method of corrective osteotomy for thumb duplication reconstruction in the adults. In: Ogino T (Ed.) Congenital differences of the upper limb. Proceedings of the fifth international symposium on congenital differences of the upper limb, May 2000. Yamagata University School of Medicine, Japan, 2000, 49–54. Received: 18 March 2006 Accepted after revision: 8 January 2007 Dr Fok-Chuan Yong, Senior Consultant Hand Surgeon, Department of Hand Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. Tel.: +65 6321 4588; fax: +65 6227 3573. E-mail: [email protected]
r 2007 The British Society for Surgery of the Hand. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhsb.2007.01.005 available online at http://www.sciencedirect.com
Metacarpal and phalangeal fracture malunions with significant angulation deformity are associated with bone shortening, prominence of the metacarpal head in the palm or pseudoclaw deformity and may be symptomatic. If so, they may need corrective osteotomy procedures. Conventional methods of closing, or opening, wedge osteotomy do not restore the length of the bone exactly. Simultaneous correction of the angular deformity and restoration of bone length can be addressed by a trapezoid rotational bone graft osteotomy. A double osteotomy is done and the segment of bone is rotated and re-inserted as a bone graft. This was done successfully in four metacarpal and two phalangeal fracture malunions with angulation deformities. Journal of Hand Surgery (European Volume, 2007) 32E: 3: 282–288 Keywords: metacarpal phalangeal malunion, trapezoid osteotomy
Malunion of metacarpal fractures with dorsal angulation deformity may result in significant metacarpal shortening and/or prominence of the metacarpal head in the distal palm. Proximal phalangeal fracture malunion with volar angulation deformity may result in bone shortening, pseudoclaw deformity and decrease in range of motion of the joints of the finger. Both of these malunions may result in painful hand grasp and/or decreased grip strength. These problems are usually experienced when the angle in the metacarpal shaft is greater than 301 or the shortening is greater than 2 to 5 mm and when the angle is greater than 25 to 301 in the proximal phalanx (Green, 1986; Lee and Jupiter, 2000; Stern, 2005; Wolfe and Elliot, 1996). Correction of these angular deformities has previously been achieved by either a closing wedge or an opening wedge osteotomy at the fracture site. However, these procedures do not restore the length of the bone to its initial pre-fracture length. In a closing wedge osteotomy of 301 or greater, there may be significant shortening in the length of the bone as a result of removal of the wedge of bone (Fig 1). The geometrical gain in length by straightening the bone is, to some extent, negated by this shortening. In an opening wedge osteotomy, there is lengthening of the bone, resulting in an over-correction of bone length (Fig 2). The latter procedure also involves harvesting a bone graft from a distant site, with the inherent risk of donor site morbidity (Cockin, 1971). Stabilisation of the bone graft can also be difficult. Restoration of the bone length, whilst correcting the angular deformity, can be addressed by the trapezoid rotational bone graft osteotomy technique (Fig 3), the use of which is illustrated in five patients in this study.
motion of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. Their pre-operative malunion angles averaged 381 (range 321–451). Another two patients with two proximal phalangeal fracture malunions with volar angulation of the little fingers had pseudoclaw deformities. One of them complained of having decreased grip strength and the other of painful grasp function. The former had decreased range of motion of the MCP joint and the latter had decreased range of motion of the PIP joint. In addition, the former patient had a volar subluxation of the proximal phalanx at the MCP joint. This may have occurred following two previous attempted operations to correct the deformity in his right little finger. He had sustained the injury to his little finger more than ten years earlier and the last operation was approximately five years ago. Their preoperative malunion angles were 601 and 501, respectively. All five patients were men of average age 32.5 (range 20–51) years (Table 1). Corrective osteotomies, as described below, were carried out to the metacarpals and phalanges at the sites of angulation. Surgical technique for metacarpal dorsal angulation (Figs 3 and 4) Pre-operatively, the angle of deformity a1 is measured on the lateral view radiograph of the metacarpal. The operative angle of osteotomy is then calculated. In a closing wedge osteotomy, the osteotomy is performed at two sites, proximal and distal to the apex of the dorsal angulation, at an angle perpendicular to the bone such that they meet at the far cortex and each osteotomy corrects 12a : In our procedure, the osteotomies are done further apart to cut out a trapezoid segment of bone and the angle of osteotomy from the perpendicular to the bone should be 14a ; as this segment of bone is removed, rotated and re-inserted as a free bone graft. The two
PATIENTS AND METHOD Three patients with four metacarpal fracture malunions with dorsal angulation presented with painful hand grasp function, although they had normal ranges of 282
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283
Fig 1 Closing wedge osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). Wedge osteotomy of a1 is as shown and (C) if a wedge of bone is removed, angulation is corrected but bone lengthening, as shown by (b), falls short of the correct and full length.
Fig 3 Trapezoid rotational bone graft osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). An osteotomy at 14a to the perpendicular to the bone is done at two sites to create a trapezoid bone segment, (C) the segment of bone is removed, rotated and re-inserted as shown in (D) then stabilised with a metal plate and screws. The bone length (b) is restored to its initial length.
Fig 2 Opening wedge osteotomy: (A) initial length of the metacarpal bone, (B) malunion with angular deformity of a1 and shortening of the bone (a). Perpendicular osteotomy is done at the apex of the angulation of the bone and (C) if an opening ‘‘wedge’’ osteotomy is done and a bone graft inserted, the lengthening (b) obtained is overlong compared to the initial bone length.
sites of the osteotomy are placed at a distance apart such that the shorter cortex of this trapezoid segment of bone is of a sufficient length for the stable placement of a screw, i.e. three times the diameter of the screw-being used. For example, if the diameter of the screw is 1.5 mm, then this cortex length should be at least 4.5 mm. The fixation of the corrective osteotomy is by metal plate and screw internal fixation. A 1.5 mm or
2.0 mm mini-plate may be used, depending on the size of the bone and the surgeon’s choice. A straight plate is used for the metacarpal bone and should be, at least, a six-hole plate. The malunited fracture site is exposed from a dorsal approach. The trapezoid segment of bone is marked out for osteotomy, as described above, such that the palmar cortex will be at least three times the diameter of the metal screws which will be used later for internal fixation of the bone. The angle of osteotomy is measured from the perpendicular to the bone towards the angle of the deformity, proximally and distally (Fig 3B). Placing a K-wire perpendicular to the axis of the bone may facilitate this marking process. Following the osteotomy, the trapezoid segment of bone is removed, rotated 180o% and re-inserted as an interposition bone graft (Fig 3C and D). The bone segments are aligned, reduced and internally fixed with a compression metal plate and screws (Fig 3D).
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Table 1—Patient details pre- and postsurgery Case
Sex
Age (years)
1
M
20
2
M
20
3
M
22
4
M
48
5
M
51
Bone involved
Angulation
Symptoms
Pre-op (degrees)
Post-op (degrees)
Pre-op
Right 5th MC Left 4th MC Left 5th MC Right 5th MC Right little PP
45
0
32
0
Painful grip Painful grip
35
0
40
0
60
15
Right little PP
50
0
Painful grip Pseudoclaw, weak Pseudoclaw, Painful grip
Grip strength (kg force)
Post-op Pre-op (R/L) No pain No Pain
No pain No claw, strong grip No claw, no pain
ROM (MCPj/PIPj)
Bone union (months) Prox/ distal
Post-op (R/L)
Pre-op
Post-op
–
–
Full ROM
Full ROM
3/3
38/40
38/43
Full ROM
Full ROM
4/4
Full ROM
Full ROM
4/4
–
–
-
FROM
4/8
35/45
43/48
601/1001 subluxed MCPJ
801/1001 no subluxed MCPJ
3/3
–
33/36
901/601
901/851
6/4
MC: metacarpal; PP: proximal phalanx; MCPj: metacarpophalangeal joint; PIPj: proximal interphalangeal joint; ROM: range of motion.
The centre screw to the bone graft segment is placed first, followed by compression fixation to the proximal segment with an eccentrically placed screw. This is repeated for compression fixation of the distal bone segment to the middle bone graft segment. The alignment of the reduction and the fingers are checked and confirmed. The remaining screws are then inserted in neutral positions. This procedure restores the bone to its initial pre-fracture length whilst correcting the angulation deformity: no bone is removed or added. Stable ‘‘rigid’’ bone fixation with a mini-plate and screws allows immediate postoperative mobilisation. Surgical technique for proximal phalangeal volar angulation (Fig 5) Similar pre-operative measurements are done. The proximal phalanx is exposed through a dorsal skin incision and the extensor tendon split. Commonly, the fracture malunion site is at the base of the phalanx and the proximal osteotomy site is placed such that there is sufficient length of bone proximally for placement of the transverse arm of the T-plate, which will be used for internal fixation of the bone. Since the apex of the angulation deformity is volar and the surgical approach is dorsal, the angle of osteotomy from the perpendicular to the bone is measured away from the angle of the deformity. Otherwise, the procedure is similar to that for the metacarpal, described above, except that a T-plate and screws are used for stable bone fixation.
The longitudinal arm of the plate should have at least four-holes. Care should be taken when using the power saw for the osteotomy of the proximal phalanx as the flexor tendon lies in a shallow trough on the volar surface of the bone. The flexor tendon was partially cut in case 4 (Table 1) and required repair primarily. He subsequently required flexor tendon rehabilitation incorporated into the post-operative therapy programme. An osteotome was used for completion of the osteotomy in case 5 to avoid this problem. Active and passive joint mobilisation therapy commences on the first postoperative day. It has been our experience that patients will mobilise only the joints that are painless on mobilising through the full range of motion. Thus, therapy is focused on the joints that are expected to be painful with full range of motion. This frequently occurs at the MCP joint in metacarpal fractures and at both the MCP and PIP joints in phalangeal fractures. After the proximal phalangeal osteotomy, a PIP joint extension splint is used between exercise sessions if full active extension is not achieved by two weeks after surgery, to help prevent PIP joint volar plate contracture. The ranges of motion at the MCP and PIP joints were measured at one week and, thereafter, monthly until fracture union was seen on X-rays of the osteotomy. Grip strength was measured at grip position 2 of a Jamar dynamometer (TEC, New Jersey 07012, USA). Radiographs of the metacarpals or phalanges were done postoperatively and at six weeks, three months and,
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thereafter, monthly to confirm retention of the correction and assess bony union.
RESULTS Radiographic illustration of case 1, with malunion of the fifth metacarpal, is shown in Fig 4. The angle of deformity is measured in the lateral view (Fig 4A). The trapezoid shaped rotational bone graft is about the optimal size for placement of one screw i.e. the shorter cortex is about 4.5 mm long which is three times the diameter of the 1.5 mm screw used (Fig 4B and C).
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Radiographic illustration of cases 2, with fourth and fifth metacarpal malunions, and 5, with proximal phalanx malunion in the little finger, are shown in Figs 5 and 6, respectively. Table 1 shows the details of measurements pre- and postoperatively. The angulation deformities were fully corrected in all the metacarpals and one proximal phalanx and 75% corrected in the other proximal phalanx, which had the largest angle of deformity. The postoperative periods were uneventful. Bone union was achieved by three to four months, except for the proximal interface of the bone graft in case 3 and the distal interface in case 5. These achieved bone
Fig 4 X-rays of malunion of the right fifth metacarpal in case 1: (A) illustration of a 451 angular deformity of the fifth metacarpal on lateral and posteroanterior X-ray views, (B) illustration of stable fixation of the trapezoid bone graft with a plate and screws on a posteroanterior X-ray view and (C) illustration of early union of the bone graft osteotomy on an oblique X-ray view.
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Fig 5 X-rays of malunions of the right fourth and fifth metacarpals in case 2: (A) pre-operative posteroanterior and lateral X-rays illustrating the metacarpal malunions and (B) posteroanterior and lateral X-rays taken at four months, illustrating consolidated bone union of the osteotomies.
union on X-ray at eight and six months, respectively. Considering that this is a bone grafting procedure, we consider bony union at four months to be acceptable. Thus, there was delayed union in 2 out of the 12 of the osteotomy sites, or interfaces of the cortical bone grafts. All of the patients, except case 1, had removal of the implants carried out at seven months to one and a half years after surgery. There were no cases of re-fracture after removal of the implants. Painful grasp was completely relieved in all the cases. The pseudoclaw deformities were corrected in the two
cases with proximal phalangeal malunion. The MCP joint ranges of motion were all maintained at the pre-operative full range of motion. The PIP joint ranges of motion for the cases of proximal phalangeal malunion improved by 201 and 251, respectively. However, they remained short of the normal range by 101 and 151, respectively. Grip strength improved post-operatively in the two cases who had comparative measurements done pre-operatively. Case 4 who suffered an accidental partial cut flexor tendon did not have any complications arising from it and there were no trophic or sensory problems.
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Fig 6 Clinical photographs and X-rays of malunion of the right little finger proximal phalanx in case 5: (A) illustration of the pseudoclaw deformity of the little finger, (B) the deformity is partially corrected postoperatively, although an extension lag at the PIP joint remains, (C) posteroanterior and lateral X-rays showing the malunion of proximal phalanx of the little finger and (D) postoperative posteroanterior and lateral X-rays showing the correction of the malunion, bone union at the proximal osteotomy site and delayed bone union at the distal osteotomy site.
DISCUSSION The common deformity seen in metacarpal shaft fracture malunion is dorsal angulation. In proximal phalanx basal fracture malunion, this volar angulation. These result in shortening of the bone (Fig 1A and B). The metacarpal head may be prominent in the palm, causing discomfort on gripping, and the MCP joint centre of rotation moves more palmar in relation to the intrinsic muscles. A pseudoclaw deformity commonly occurs in angulated fractures of the base of proximal phalanx (Fig 6A). The shortening is greater when the angulation occurs towards the midshaft of the bone. The metacarpal head is more prominent in the palm in distal metacarpal shaft angulation (Wolfe and Elliot, 1996). These factors contribute to the symptoms of painful grasp and decreased grip strength (Seitz and Froimson,
1988; Stern, 2005; Wolfe and Elliot, 1996). Gropper and Bowen (1984) reported their indications for open reduction and internal fixation of acute metacarpal fractures, which included shortening of more than 2 mm and dorsal angulation of 251 in the fourth metacarpal and 30o% in the fifth metacarpal. Most authors report that metacarpal malunion is acceptable if the resultant bone shortening is not greater than 2 to 5 mm and angulation not greater than 201 to 301 (Burkhalter, 1990; Green, 1986; Lee and Jupiter, 2000; Wolfe and Elliot, 1996). In the presence of symptomatic metacarpal and phalangeal shaft fracture malunion with angulation deformity, the surgical procedure should correct the angle of deformity and restore the length of the bone. Correction of the angle of deformity can be achieved by the conventional methods of either a closing, or an opening, wedge osteotomy at the fracture site (Seitz and
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Froimson, 1988). However, neither of these procedures restores the length of the bone exactly. In opening wedge osteotomy, there is a significant lengthening of the bone, resulting in an over correction of bone length (Fig 2). It also involves harvesting a bone graft from a distant site, with the inherent risk of donor site morbidity (Cockin, 1971). Stabilisation of the bone graft may also be difficult. In a closing wedge osteotomy of 301, or greater, there is significant shortening in the length of the bone as a result of the removal of the wedge of bone (Fig 1). Wolfe and Elliot (1996) reported that this dorsal length loss is usually offset by the geometrical length gain achieved by the angular correction. However, this geometrical length gain only offsets the original geometrical length loss resulting from the initial fracture with angulation deformity. It is insufficient to compensate for the additional length of bone loss contributed by the closing wedge osteotomy. The wedge of bone could simply be rotated through 180o% and then re-inserted as a free bone graft. If this is done, the angle of osteotomy should be halved (Yong et al., 2000). However, it is difficult to achieve a stable fixation of the small wedge of bone with the angled edge at the near cortex. If the osteotomy is done similarly at two sites, but further apart, to get a trapezoid block of bone with sufficient length for placement of a screw in a stable plate and screws fixation construct, fixation is easier and more stable. In this reconstruction, the angle of osteotomy will need to be further halved, i.e. onequarter of the angle of deformity (Fig 3). The smaller angle of osteotomy also facilitates a compression fixation technique to enhance bone union. A metal plate and screw compression fixation is recommended for maximum stable internal fixation of the osteotomy (Black et al., 1985). It also enables immediate postoperative joint mobilisation. The osteotomy is done at the site of malunion and no bone is removed, or added. Therefore, it restores bone length to its initial, prefracture length, whilst correcting the angle of deformity. Our patients had metacarpal shaft angular deformities of 321 to 451 and proximal phalanx basal angular deformities of 501 to 601. There were no problems at surgery to correct these angulations except in one case, that with a 601 angulation at the base of the proximal phalanx, which only achieved 75% correction. Four out of five of the patients had symptoms of pain on grasp function. These all resolved and none showed deterioration of their symptoms. Grip strength also improved in the patient who complained of weak grip. Delay of
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union might be considered a complication of this trapezoid osteotomy procedure as this occurred in two of the 12 osteotomy sites. To minimise the likelihood of this occurring, or this having any ill effects, compression plate and screw bone fixation is recommended for this procedure. In this small series, there were no problems at surgery or with ultimate bony union of the resultant free cortical bone graft. Correction of the angular deformity and precise restoration of the metacarpal and phalangeal bone length are possible using this technique and should contribute to pain relief and improvement in grip strength. References Black D, Mann RJ, Constine R, Daniels AU (1985). Comparison of internal fixation techniques in metacarpal fractures. Journal of Hand Surgery, 10A: 466–472. Burkhalter WE. Hand fractures. In: Greene WB (Ed) Instructional course lectures. Chicago, AAOS, 1990, Vol. 39: 249–253. Cockin J (1971). Autologous bone grafting – complications at the donor site. Proceedings and reports of councils and associations. Journal of Bone and Joint Surgery, 53B: 153. Green DP (1986). Complications of phalangeal and metacarpal fractures. Hand Clinics, 2: 307–328. Gropper PT, Bowen V (1984). Cerclage wiring of metacarpal fractures. Clinical Orthopaedics and Related Research, 188: 203–207. Lee SG, Jupiter JB (2000). Phalangeal and metacarpal fractures of the hand. Hand Clinics, 16: 323–332. Seitz WH, Froimson AI (1988). Management of malunited fractures of the metacarpal and phalangeal shafts. Hand Clinics, 4: 529–536. Stern PJ. Fractures of the metacarpals and phalanges. In: Green DP, Hotchkiss RN, Pederson WC, Wolfe SW (Eds) Green’s operative hand surgery, 5th Edn. Philadelphia, Churchill Livingstone, 2005, Vol. 1: 297–299 and 324–327. Wolfe SW, Elliot AJ. Metacarpal and carpometacarpal trauma. In: Peimer CA (Ed). Surgery of the hand and upper extremity, New York, McGraw-Hill, 1996, Vol. 1: 883–920. Yong FC, Teoh LC, Liau KH (2000). A new method of corrective osteotomy for thumb duplication reconstruction in the adults. In: Ogino T (Ed.) Congenital differences of the upper limb. Proceedings of the fifth international symposium on congenital differences of the upper limb, May 2000. Yamagata University School of Medicine, Japan, 2000, 49–54. Received: 18 March 2006 Accepted after revision: 8 January 2007 Dr Fok-Chuan Yong, Senior Consultant Hand Surgeon, Department of Hand Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. Tel.: +65 6321 4588; fax: +65 6227 3573. E-mail: [email protected]
r 2007 The British Society for Surgery of the Hand. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhsb.2007.01.005 available online at http://www.sciencedirect.com