Modification of the extension block Kirschner wire technique for mallet fractures

A modification of the extension block Kirschner wire technique that is used for closed reduction of mallet fractures is described. Eighteen mallet avulsion fractures of the distal phalanx treated with this modification were included in this prospective study. The fingers affected were nine small fingers, eight ring fingers, and one long finger. Surgical indications included fractures involving more than 33% of the articular surface and fractures associated with subluxation of the distal phalanx that could not be corrected by closed reduction. The average joint surface involvement was 39.8%. At followup, only one patient had pain, and that was graded as minimal. Objectively, congruous and satisfactory joint surfaces were present in 17 patients. No patient had pseudarthrosis. The average active flexion of the distal interphalangeal joint was 81.1 degrees and the average extensor lag was 1.6 degrees. Neither pin tract infections nor migration of the pins occurred. The average followup was 27.3 months. This modification increased range of motion at the distal interphalangeal joint and showed a trend toward reduced permanent extensor lag when compared with the original method. This technique should be considered when treatment of the mallet fracture is being planned using the extension block Kirschner wire technique.     

The Ishiguro extension block technique for the treatment of mallet finger fracture: indications and clinical results

The results of extension block Kirschner wire fixation for the treatment of mallet fractures of the distal phalanx were retrospectively assessed in 65 consecutive patients. The indications for this technique were the presence of a large bone fragment, and palmar subluxation or the loss of joint congruity of the distal interphalangeal joint. Using the Wehbé and Scheider classification there were 27 type IB, 19 type IIB, 17 type IA, and 2 type IIA fractures. According to the Crawford rating system there were 46% excellent, 32% good, 20% fair and 2% poor results. We believe that this technique, when properly applied, produces satisfactory results.     

Simultaneous fracture-dislocations of the distal and proximal interphalangeal joints

Sixteen cases of simultaneous fracture-dislocations of both the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints in the same finger that were treated during the past 10 years were classified into three types: the swan-neck injury (dorsal fragment of the base of the distal phalanx at the DIP joint and palmar fragment of the base of the middle phalanx at the PIP joint); the double-hyperextension injury (palmar fragments at the DIP and PIP joints); and the straight-finger injury (with dorsal and palmar bone fragments at the DIP joint). The results of treatment were more satisfactory in PIP joints than in DIP joints.     

Mallet fractures

In a review of 160 mallet fingers, forty-four were found to have a fracture of the distal phalanx. Of these mallet fractures, twenty-one could be followed for a mean of 3.25 years (range, six months to eight years). Six had been treated surgically and fifteen had simply been splinted. Of these twenty-one mallet fractures, all but one had a good result irrespective of the form of treatment. Bone-remodeling occurred in all digits (including two with fibrous union), with reconstitution of the articular surface and preservation of the joint space as seen on radiographs. There was also a near-normal range of painless motion in all but one finger. Poor patient compliance was an occasional difficulty when conservative treatment was used. Surgical treatment was difficult and unreliable; it offered no advantage over conservative treatment and had a greater rate of morbidity. The major "complication" of both forms of treatment was a bone prominence on the dorsum of the distal interphalangeal joint. These findings suggest that most mallet fractures can be treated conservatively, ignoring joint subluxation and the size and amount of displacement of the bone fragment.     

A biomechanical study of distal interphalangeal joint subluxation after mallet fracture injury

PURPOSE: There is no consensus in the literature regarding the size of a mallet fracture fragment that may lead to subluxation of the distal interphalangeal (DIP) joint. The purpose of this study was to determine the relationship between the size of the dorsal articular fragment and DIP joint subluxation in a cadaveric mallet fracture model. METHODS: Twenty-nine fresh-frozen fingers without evidence of DIP joint osteophytes were dissected to the metacarpal base. The mean age of the 17 donors at the time of death was 69 years (range, 46 to 89 years). Obliquely oriented fractures through the dorsal lip of the distal phalanx were randomly created with an osteotome (range, 27% to 69% of the joint surface). Each finger was fully flexed and extended 1,200 times by applying alternating tension to the flexor and extensor tendons. Fluoroscopic images were obtained and digitized for measurements of fracture fragment size and DIP joint subluxation. RESULTS: Sixteen DIP joints remained reduced and 13 distal phalanges subluxated palmarward. Subluxation was not observed when the fracture fragment measured less than 43% of the joint surface, whereas subluxation consistently occurred when the defect measured greater than 52% of the articular surface. Subluxation averaged 18% +/- 7% of the overall joint surface in these specimens. There was no correlation between the amount of joint subluxation and the percentage of articular surface damage (p = .22). CONCLUSIONS: This study supports the concept that a mallet fracture with a large articular fragment may be unstable. Palmar subluxation of a DIP joint without preexisting arthritic deformity is expected when more than one half of the dorsal articular surface is injured.     

Modified extension-block K-wire fixation technique for the treatment of bony mallet finger

This article describes the treatment of a bony mallet finger deformity using 2 extension-block Kirschner wires (K-wires) with a transarticular K-wire fixation technique for precise alignment of the terminal extensor tendon-bone relationship and effective immobilization of the distal interphalangeal joint. Twenty-nine patients (33 fingers) with a bony mallet finger deformity and fracture fragment involving more than one-third of the articular surface were treated surgically. The fracture fragment was fixed and the mallet finger deformity was corrected in all patients using modified extension-block K-wires (2 dorsal extension-block pins) with a transarticular K-wire (volar side pin) fixation technique. Active motion of the proximal interphalangeal and metacarpophalangeal joints was not restricted. The wires are removed in the clinic 6 weeks postoperatively when the bridging trabeculae were observed in the radiographs, and immobilization in a stock splint was continued for an additional 2 weeks. According to Crawford's evaluation criteria, there were 24 (73%) excellent, 7 (21%) good, and 2 (6%) fair results. Three patients showed radiological signs of mild degenerative changes, which did not limit their daily activities. Nail ridging occurred in 3 cases (9%), which disappeared after an average of 6 months with normal growth, and mild scarring at the dorsal pin site occurred in 2 cases (6%). Modified extension-block K-wires with a transarticular K-wire fixation technique is an acceptable alternative treatment modality for the management of bony mallet finger deformities with or without subluxation of the distal phalanx.     

Extension-block pinning for treatment of displaced mallet fractures

Mallet injuries are common in active individuals, particularly those who participate in sports such as basketball and football. Although a majority of patients with displaced mallet fractures are treated conservatively with extension splinting, their treatment is often complicated by residual loss of extension and fracture displacement secondary to unfavorable fracture biomechanics and poor patient compliance. An attractive alternative to nonoperative treatment is the minimally invasive technique of extension-block percutaneous pinning. Extension-block percutaneous pinning allows anatomic restoration of the articular surfaces and avoids the complications associated with closed treatment. The technique is easy to perform and is an effective, safe alternative to the conservative treatment of displaced mallet fractures, particularly those associated with joint subluxation.     

Mallet finger and fractures

Mallet finger is often associated with a dorsal fracture of the base of the terminal phalanx. This is sometimes referred to as a mallet finger fracture but such a term is unwise because it may be applied to all fractures in this position. The purpose of this paper is to justify this warning and to distinguish between such fractures with and without mallet finger. However treated, mallet finger, with or without fracture, often leads to persistent loss of some active extension of the finger. In 11 cases of fracture without mallet finger in which there was no subluxation, full function was regained by comfortable support and early activity; operation was not required. In 2 cases with subluxation, the joint became stiff and open fixation may lead to a better result.     

Unstable mallet fractures: a comparison between three different techniques in a multicenter study

Objective： Management of mallet fractures is still a matter of discussion throughout the literature. For some authors, mallet fractures involving more than 1/3 of the articular surface and palmar subluxation of the distal phalanx require surgical treatment. In this study we retrospectively compared three different techniques for mallet fractures： Kirschner wire fixation with extension block pinning （EBP） of the distal interphalangeal joint, Kirschner wires used as joysticks （KWJ） and interfragmentary miniscrews for open reduction and internal fixation （ORIF）.
Methods： Fifty-eight mallet fractures with palmar subluxation in 58 patients were treated with the aforementioned surgical techniques. Twenty mallet fractures in 20 patients 18 to 70 years old （average 42 years） were operated upon by EBP, 16 patients 22 to 56 years old （average 56 years） were operated upon using KWJ and 22 patients 22 to 54 years old （average 36 years） received OR/F. Follow-up time was 6 to 58 months （average 21 months）. The following intraoperative parameters were considered： intraoperative time, number of Kirschner wires/screws and technical problems. Postoperative parameters included work absence and complications. The radiological evaluation was based on A-P and lateral views preoperatively and interviews at follow-up time. Bone union was defined by radiological evidence of bone trabeculae crossing the fracture site on at least one view. Clinical evaluation involved range of motion （ROM） test with a goniometer. Based on these measurements, a functional Crawford score was established.
Results： All fractures healed. In the KWJ group, intraoperative time was shorter and total ROM was wider （72° vs 58° and 54 °）; in the ORIF group, return to work was faster （2.7 weeks vs 7.2 weeks and 6 weeks） but a little higher complication rate due to screw positioning has been found. Functional results as to total ROM, distal interphalangeal lag extension and Crawford classification were similar.
Conclusions： We demonstrate the advantages of the use of the three techniques and bone consolidation in all cases with no signs ofosteoarthritis. Screw fixation is more technically demanding （longer intraoperative time and more complications） but allows earlier mobilization and faster returning to work. EBP and KWJ techniques are faster to perform with no complications but require a careful management of the pin tracts. There is no statistically significant difference as to functional results.     

Operative treatment of mallet finger due to intra-articular fracture of the distal phalanx

Treatment of a mallet finger due to an intra-articular fracture of the distal phalanx involving one-third or more of the articular surface is controversial. Thirty-three digits with such fractures were treated by open reduction and internal fixation with Kirschner wires. Of these 33 fractures, 13 were associated with subluxation of the distal phalanx. After an average follow-up period of 29 months, the average loss of extension of the distal phalanx was 4 degrees, and the average flexion of the distal interphalangeal joint was 67 degrees. Radiographs of the distal joint in 27 digits appeared normal, while in the remaining 6 digits, slight degenerative changes were noted. In one there was a minor surgical complication. By using the operative technique described, a congruous reduction of the inta-articular fracture and satisfactory function were achieved.     

Mallet finger

Mallet finger involves loss of continuity of the extensor tendon over the distal interphalangeal joint. This common hand injury results in a flexion deformity of the distal finger joint and may lead to an imbalance between flexion and extension forces more proximally in the digit. Mallet injuries can be classified into four types, based on skin integrity and the presence or absence of bony involvement. Although various treatment protocols have been proposed, splinting of the distal interphalangeal joint for 6 to 8 weeks has yielded good results while minimizing morbidity in the majority of patients. Surgical management may be considered for acute and chronic mallet lesions in patients who have failed nonsurgical treatment, are unable to work with the splint in position, or have a fracture involving more than one third of the joint surface.     

Conservative treatment of mallet thumb

Four cases of mallet thumb were treated conservatively by splinting the interphalangeal joint of the thumb in extension using the Stack splint. Two patients had sharply cut the extensor tendon on the dorsum of the proximal phalanx and two had avulsion of the extensor tendon from the base of the distal phalanx. Eight weeks of continuous splinting was followed by 2 weeks of night splinting. Six months of follow-up revealed excellent range of motion in all four cases.     

Base of distal phalanx fracture in children: a mallet finger mimic

The authors present a series of seven juxtaepiphyseal fractures at the base of the distal phalanx of the finger. Prior to closure of the epiphysis, the fracture line is usually through the growth plate (Salter-Harris type I or II) or 1 to 2 mm distal to the plate. Clinically the injury looks like a mallet finger, but the pathoanatomy is not that of the classic mallet. All seven of these fractures were treated by closed reduction, six fractures were fixed by a Kirschner wire, and one was held by splinting only. All healed without complications.     

Current concepts: mallet finger

Loss of the extensor mechanism at the distal interphalangeal (DIP) joint leads to mallet finger also known as baseball finger or drop finger. This can be secondary to tendon substance disruption or to a bony avulsion. Soft tissue mallet finger is the result of a rupture of the extensor tendon in Zone 1, and a bony mallet finger is the result of an avulsion of the extensor tendon from the distal phalanx with a small fragment of bone attached to the avulsed tendon. Mallet finger leads to an imbalance in the distribution of the extensor force between the proximal interphalangeal (PIP) and DIP joints. If left untreated, mallet finger leads to a swan neck deformity from PIP joint hyper extension and DIP joint flexion. Most mallet finger injuries can be managed non-surgically, but occasionally surgery is recommended for either an acute or a chronic mallet finger or for salvage of failed prior treatment.     

伸肌腱止点重建治疗锤状指畸形

目的介绍应用重建伸肌腱止点治疗锤状指畸形的方法和疗效。方法对13例锤状指患者,于末节指骨终腱止点处作粗糙面熏取掌长肌腱游离移植。肌腱近端用3/0缝合线重叠缝合,远端用4/0丝线作“8”字缝合后绕行至指端皮肤外打结。远侧指间关节用直径1.0mm克氏针固定过伸位10°～15°,近侧指间关节石膏托固定屈曲位30°～40°。4周后拆除牵引线及外固定进行近侧指间关节及掌指关节功能锻炼,6周后拔除克氏针进行末节屈伸功能锻炼。结果随访2个月～2年,按Dargan功能评定法:优11例,良1例,可1例,优良率92.3%。结论伸肌腱止点重建术是治疗锤状指畸形的有效方法。     

Outcomes Following Operative Treatment of Adolescent Mallet Fractures

Background

Many surgeons advocate for surgical intervention of adult mallet fractures that involve either subluxation of the distal interphalangeal (DIP) joint or those that involve more than one-third of the articular surface. However, the efficacy of operative treatment and complication rates are unclear regarding the adolescent population.

Questions/Purposes

The goal of this study is to evaluate the clinical outcomes following operative fixation of bony mallet fractures in the adolescent population.

Methods

Seventeen patients with bony mallet fractures treated surgically were retrospectively reviewed. Twelve patients were treated by closed reduction with extension block pinning. The other patients underwent an open reduction and pin fixation. The average age was 15.2 years (13–18). Most injuries were sport related. The average time from injury to presentation was 17 days and from injury to surgery was 24.5 days. Nine patients had subluxation at the DIP joint and all involved at least one-third of the articular surface.

Results

The average time from surgery to pin removal was 28 days (19–46). All distal phalanx physis were closed or nearly closed. One patient reported pain at the final follow-up. Two patients (11.8%) had major complications. One had an extension contracture postoperatively, did not attend therapy, and re-fractured 5 months later requiring reoperation. The second was treated delayed (32 days) and lost fixation, requiring revision surgery and antibiotics for a superficial infection. Two patients with delayed treatment (32 and 44 days) had an extensor lag (11.8%).

Conclusions

Operative treatment of mallet fractures with subluxation or involving more than one-third of the articular surface appears effective. Pin removal 4 weeks postoperatively appears adequate. Complications occurred with delayed presentation and non-compliance.

     

Repair of chronic mallet finger deformity using Mitek micro arc bone anchor

Surgical correction of chronic mallet finger caused by terminal tendon disruption was carried out in 22 patients. The distal stump of the tendon was fixed to the base of the distal phalanx with a Mitek micro arc bone anchor. In all patients the mallet finger deformity was corrected. There were 15 patients with excellent results, 5 with good results, and 2 with fair results. None of the patients had a poor result. No further treatment was needed. The Mitek micro arc bone anchor system is a reliable alternative for the treatment of chronic mallet finger deformity without proximal interphalangeal hyperextension.     

Fractures of the proximal interphalangeal joint

Fractures of the proximal interphalangeal joint constitute a broad spectrum of injuries. An understanding of the anatomy, the potential for joint instability, and the treatment options is essential to management of these fractures. Commonly observed fracture patterns involve one or both condyles of the proximal phalanx or the base of the middle phalanx. Fractures of the middle phalanx may involve the palmar lip or the dorsal lip or may be a "pilon" type of injury involving both the palmar and the dorsal lip with extensive intra-articular comminution. Intra-articular injuries may lead to joint subluxation or dislocation and must be identified in a timely manner to limit loss of motion, degenerative changes, and impaired function. These injuries range from those requiring minimal intervention to obtain an excellent outcome to those that are challenging to the most experienced surgeon. The treatment options include extension-block splinting, percutaneous pinning, traction, external fixation, open reduction and internal fixation, and volar-plate arthroplasty. Prompt recognition of the complexity of the injury and appropriate management are essential for an optimal functional outcome.     

Open reduction and screw fixation of mallet fractures

Twelve patients with mallet fractures treated by open reduction and internal fixation with small screws were reviewed at an average of 31 months after surgery. The indication for surgery was a fracture involving more than one-third of the distal phalanx articular surface or with subluxation of the distal interphalangeal joint. Loss of reduction occurred in one patient and in another one screw loosened slightly without loss of reduction. There were no nail deformities, infections, or secondary procedures. The mean range of motion was from 6 degrees (range, 0-30 degrees ) (extensor lag) to 70 degrees (range, 60-90 degrees ) flexion. Ten patients had no evidence of degenerative changes, one had minor joint space narrowing and one had significant deformity. Open reduction and screw fixation with small screws can lead to satisfactory outcome in appropriate patients.     

Treatment of mallet finger due to intra-articular fracture of the distal phalanx

When a mallet finger deformity results from an intra-articular fracture of the distal phalanx comprising more than one third of the articular surface, an accurate reduction of this fracture is necessary to prevent secondary degenerative arthritis. A technique for open reduction is described in which the distal interphalangeal joint is exposed by dividing the extensor tendon and permitting a precise reduction of the fracutre fragment. Elective division of the extensor tendon had not compromised the results.