Journal List > J Korean Soc Surg Hand > v.20(3) > 1106492

J Korean Soc Surg Hand. 2015 Sep;20(3):138-141. English.
Published online September 30, 2015.
Copyright © 2015. The Korean Society for Surgery of the Hand
Physical Therapy-Induced Secondary Bony Mallet Finger Deformity
Hyun Ho Han, Jong Yun Choi and Suk Ho Moon
Department of Plastic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Correspondence to: Suk Ho Moon. Department of Plastic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Korea. TEL: +82-2-2258-6144, FAX: +82-2-594-7230, Email:
Received March 11, 2015; Revised June 20, 2015; Accepted July 23, 2015.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


After operation for fracture in the phalangeal bones, rehabilitation is initiated in order to minimize joint stiffness if in the case, complete bony union is confirmed by hand surgeons. The described case demonstrates that bony mallet deformity can occur during physical therapy following by surgical pinning of a proximal phalangeal fracture. This mallet finger deformity occurred due to vigorous rehabilitation for correction of postoperative joint stiffness. So, when hand surgeons treat patients with proximal phalangeal fracture, it is important to minimize joint space involvement and close follow-ups accompanying imaging studies during rehabilitation period.

Keywords: Mallet deformity; Rehabilitation; Stiffness; Fracture


Mallet finger injury is characterized by discontinuity of the terminal extensor tendon resulting in an extensor lag at the distal interphalangeal (DIP) joint with or without compensatory hyperextension at the proximal interphalangeal (PIP) joint1. This leads to terminal extensor tendon tear or tendon avulsion with a bony fragment.

Snagging the extending finger on a pants cuff, a bedsheet, or other object that suddenly flexes the extending DIP joint are frequent etiologies2. Sometimes, in athletes, it is commonly seen that with a forceful blow to the tip of the finger causes sudden flexion3. And DIP joint hyperextension can also cause mallet finger secondary to a dorsal lip fracture as the hyperextended distal phalanx impacts on the head of the middle phalanx4. If left untreated, mallet finger leads to a swan neck deformity from PIP joint hyperextension and DIP joint flexion2.

The authors present a case of secondary bony mallet injury that occurred while performing physical therapy during a rehabilitation program after proximal phalangeal fracture healing.


A 40-year-old man injured his right little finger by smacking on the floor after slipping down. Radiographs depicted a comminuted fracture of the head of the proximal phalanx of the little finger (Fig. 1A). The patient underwent closed reduction and fixation using longitudinal Kirschner wire at 7 days after injury (Fig. 1B), and at 5 weeks postoperatively, the authors removed the Kirschner wire and confirmed bony union (Fig. 1C). However, the patient had a limited range of motion of the PIP and DIP joints, that was 50° at the PIP joint, and 30° at the DIP joint respectively. Thus, physical therapy was prescribed and treatment was initiated at 1 month after surgery.

Fig. 1
Primary little finger fracture. (A) Radiographs depicted a comminuted fracture of the head of the proximal phalanx. (B) Postoperative radiograph demonstrating anatomic reduction by Kirschner wire fixation at 7 days after injury. (C) Lateral radiograph taken two months after closed reduction demonstrating complete bony union.
Click for larger image

A physical therapist aided in passive exercise for the patient about 1 week, and gentle active exercise was added to the passive exercise. Then the splint was changed to a dynamic one, blocking flexion and extension exercises were done. Compression bandages were used to reduce edema and deep heat therapy and hydrotherapy was also used for rehabilitation.

Lost to follow-up occurred after the patient being transferred to a local rehabilitiation facility. However, the patient had revisited this institution due to a mallet deformity at 5 months after the surgery (Fig. 2A).

Fig. 2
Secondary bony mallet deformity. (A) The patient represented due to a distal phalangeal bone fracture on his little finger. (B) The extension block method was used to treat the bony mallet injury.
Click for larger image

Mallet deformity was treated with extension-block percutaneous Kirschner wire pinning using the Ishiguro technique (Fig. 2B)5. The Kirschner wire was removed 6 weeks after second surgery, and the patient was followed up for 6 months. Finally, the patient's range of motion was 90° at the PIP joint, and 45° at the DIP joint. The fracture united without further complications, and no extension lag was observed.


In our cases, while the fracture was united, the joint motion of the injured finger was limited due to adhesion that hindered tendon gliding and led to joint stiffness caused by fixed Kirschner wire that was passing through the joint.

In patients with phalangeal fractures in hand, rehabilitation is generally initiated when union is confirmed and from then on, the surgeon tends to consider their job completed and delegate treatment to physical therapists. In fact, the subject of this case report presented to a surgeon two weeks after secondary extension lag developed. Lack of observation by a hand surgeon after operation could be a factor for delayed diagnosis.

It has been reported, complication rate (infection, joint incongruity, implant failure and residual pain) after phalangeal fracture treatment was increased during Kirschner wire fixed through involving joint space6, 7. Sometimes, although it has been treated by surgical fixation, these complications led to worse result than conservative treatment7, 8.

As mentioned in our case report, penetrating a joint space during fixation of phalangeal fracture using Kirchner wire could lead to increased joint stiffness, longer rehabilitation period and may affect the range of joint motion. It has provided the authors a valuable lesson that is important to select surgical methods involving minimal joint spaces.

Rehabilitation after proximal phalangeal bone fracture operation is an important treatment step, which aims at mobilizing digital chains as soon as possible to minimize finger stiffness9. Therefore, during physical therapy undertaken to extend the movement range of a joint in a finger fracture patient, surgeon must always remember that the treatment process is not over until the physical therapy is actually finished. Regular X-ray follow-up is important, especially regarding the possibility of mallet deformity due to secondary fracture. It would also be wise to educate physical therapists of this possibility.

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