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Total knee arthroplasty covered with pedicle peroneal flap
The Journal of Arthroplasty Vol. 11 No. 4 1996
Case Report
Total Knee Arthroplasty Covered With Pedicle Peroneal Flap Kazuo Ikeda, MD, Yutaka Morishita, Eiji S h i m o z a k i ,
MD, Tadami Matsumoto,
MD, Akira Nakatani, MD, and Katsuro
MD,
Tomita, MD
Abstract: Three cases of total knee arthroplasty (TICA) covered with pedicle peroneal flaps are reported. One peroneal flap was performed after TKA to correct postTKA skin necrosis. Two peroneal flaps were performed before TKA to replace previous traumatic scar formed around the knee. All three TKAs were successful after the procedure. The thickness, elasticity, appearance, and durability of the peroneal flaps were more suitable for the skin around the knee than the gastrocnemius muscle flap or the local fasciocutaneous flap. As the peroneal flap was elevated as a pedide flap, freedom of transfer was good, microanastomosis was not necessary, and no donor sites were needed from the contralateral limb. Scar tissue around the knee can be effectively replaced by the pedicle peroneal flap before TKA. Key words: total knee arthroplasty, peroneal flap, infection, scar tissue, complication.
Case Reports
As m o d e r n design and technique of total knee arthroplasty (TKA) advance, the indications for this procedure h a v e increased year after year; however, complication rates h a v e also increased. The worst complication of TKA is infection. Infection rates after TKA have b e e n reported as 0.63% [1], 1.6% [2], 8.2% [3], a n d 1.2 to 12.4% [4]. A fairly freq u e n t cause of infection post-TIC¢ has b e e n skin necrosis. About 62% of infected TIC_As have had a history of prolonged postoperative drainage with failure of p r i m a r y w o u n d healing [5]. Preoperative skin condition a r o u n d the knee is also e x t r e m e l y important. Poor blood circulation and preoperative scar formation w o u l d hinder w o u n d healing. The following are three cases of TKA covered with pedicle peroneal flap that has salvaged or p r e v e n t e d skin necrosis (Table 1).
Case 1 A 53-year-old w o m a n c o m p l a i n e d of right knee pain. She h a d sustained an o p e n fracture of her right distal f e m u r complicated by osteomyelitis 30 years earlier. There was a large scar that e x t e n d e d f r o m the anterior to the lateral side of the right knee. During the operation, skin over the k n e e was handled with e x t r e m e care. As the patella could not be t u r n e d over secondary to contracture, the tibial tuberosity was elevated and fixed using screws after i m p l a n t a t i o n of prosthesis. Necrosis of the lateral edge of the incision was n o t e d on postoperative day 3 and d e m a r c a t i o n was clear o n postoperative day 10 (Fig. 1A); however, there was no sign of infection. Two weeks after the initial operation, we debrided the lesion a n d p e r f o r m e d a pedicle p e r o n e a l flap for soft tissue coverage. We designed a p e r o n e a l flap 15 cm long and 4.5 cm wide f r o m the ipsilateral leg, and the perforator f r o m the p e r o n e a l artery to the flap was identified
From the Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, Kanazawa, Japan. Reprint requests: Kazuo Ikeda, MD, Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920, Japan.
478
TKA Covered With Pedicle Peroneal Flap
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Ikeda et al.
479
Table 1. Characteristics of Three TICA Cases
Case 1 Age (years)/Sex Operations Follow-up period (years) Previous injury Length of pedicle (cm) Size of flap (cm) Location of flap
53/F Flap 3 weeks after TKA 2.5 Open fracture of the right distal femur complicated by osteomyelitis 30 years earlier 12 15 x 4.5 Top of patella
b y a D o p p l e r f l o w m e t e r (Fig. 1B). The flap was elev a t e d as a pedicle t h a t i n c l u d e d the p e r o n e a l a r t e r y a n d vein. The l e n g t h of the pedicle w a s 12 c m a n d long e n o u g h to be transferred to the lesion. Necrotic tissue o v e r the k n e e w a s c o m p l e t e l y resected. After resection, the prosthesis w a s exposed. The flap w a s passed t h r o u g h a t u n n e l u n d e r the skin a n d s u t u r e d using w a t e r t i g h t techn i q u e to c o v e r the prosthesis (Fig. 1C). The d o n o r site was t h e n c o v e r e d w i t h a split-thickness skin graft h a r v e s t e d f r o m the ipsilateral i n g u i n a l area. For the p u r p o s e of w o u n d control, the right l o w e r e x t r e m i t y was splinted a n d elevated for 7 days. D u r i n g this period, the p a t i e n t w a s a l l o w e d to a m b u l a t e w i t h a wheelchair. Physical t h e r a p y a n d r a n g e - o f - m o t i o n exercises w e r e started o n p o s t o p -
Case 2
Case 3
78tF TKA 3 months after flap 1.5 Trauma on the left tibial tuberosity during childhood
48/M TKA 3 months after flap 1.0 Open fracture dislocation of the right knee during childhood
10 9x 6 Lateral of final tuberosity
15 13 x 7 Medial of femoral condyle
erative d a y 7 a n d w e i g h t b e a r i n g w a s p e r m i t t e d o n p o s t o p e r a t i v e day 10. P o s t o p e r a t i v e r e c o v e r y w a s u n e v e n t f u l . The p a t i e n t has b e e n f o l l o w e d for 2.5 years. D u r i n g the interim, t h e r e w e r e n o signs of infection, a n d the flap w a s intact a n d cosmetically appealing. Case 2
A 7 8 - y e a r - o l d w o m a n c o m p l a i n e d of left k n e e pain. There was a large scar a n t e r i o r a n d lateral o v e r the tibial tuberosity, s e c o n d a r y to t r a u m a sustained during childhood. Poor postoperative w o u n d healing w a s anticipated f r o m o u r e x p e r i e n c e w i t h case I. R e p l a c e m e n t of extensive scar tissue w i t h a pedicle p e r o n e a l flap w a s p l a n n e d before TKA.
Fig. 1. Case i: a 53-year-old woman. (A) Ten-day postoperative view; the lateral skin edge of the incision is necrotic. (B) Design of the pedicle peroneal flap. The flap is 15 cm long and 4.5 cm wide. A dot in the flap marks the perforator branch of the peroneal artery, which is identified using a Doppler flowmeter. (C) The necrotic tissue is replaced by the pedicle peroneal flap passed through the tunnel under the skin.
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The Journal of Arthroplasty Vol. 11 No. 4 June 1996
pedicle peroneal flap 9 cm long a n d 6 cm wide f r o m the left leg was designed. The length of the pedicle was 10 cm. As the scar was inferior to the patella, a shorter pedicle w o u l d be sufficient. The scar was excised a n d the flap was passed t h r o u g h a tunnel u n d e r the skin to reach the lesion. The older age of the patient did not m a k e the procedure itself or the postoperative care m o r e complicated. Complete w o u n d healing and full recovery of muscle strength w e r e acheived before the left TIC_A, w h i c h was p e r f o r m e d 3 m o n t h s after the initial operation. The incision for the TKA was placed t h r o u g h the flap but there was no postoperative skin necrosis. The patient has b e e n followed for 1.5 years, and the flap has b e e n in excellent condition.
Case 3 A 4 8 - y e a r - o l d m a n c o m p l a i n e d of right k n e e pain. There was a large scar o n the m e d i a l side of the k n e e (Fig. 2A), s e c o n d a r y to an o p e n fracture dislocation of the right k n e e during childhood. As the p a t i e n t has extensive scar f o r m a t i o n , a pedicle p e r o n e a l flap was p l a n n e d before the TKA. A pedicle p e r o n e a l flap 13 c m long a n d 7 cm wide f r o m the right leg was designed (Fig. 2B). The length of the pedicle was 15 cm a n d was sufficient to r e a c h the opposite side of the leg. The flap was passed t h r o u g h a skin t u n n e l created o v e r the popliteal area to c o v e r the excised lesion (Fig. 2C). A posterior transfer was chosen, as an anterior transfer w o u l d h a v e placed the pedicle u n d e r
the incision for the later TKA. The d o n o r site was covered w i t h a split-thickness skin graft. Full a m b u l a t i o n was p e r m i t t e d on p o s t o p e r a t i v e day 7. A TKA was p e r f o r m e d 3 m o n t h s after the initial operation. R e c o v e r y was u n e v e n t f u l . The patient has b e e n followed up for a y e a r a n d e x p e r i e n c e d no complications.
Discussion Total knee arthroplasty was successful in salvaging and preventing poor w o u n d healing. Preoperative scar or necrotic tissue a r o u n d the knee was replaced using pedicle peroneal flaps after TKA (1 case) or before TKA (2 cases). If there is scar formation a r o u n d the knee joint due to previous t r a u m a or surgery, infection rate increases [2]. Skin necrosis occurs at a high incidence w h e n previous scar tissue is incised or elevated. Incidence increases w h e n the scar is thin and a d h e r e n t to the bone. In such cases, previous studies have reported using gastrocnemius muscle flap with skin graft [6-9] or a local fasciocutaneous flap [10]. Although the muscle flap can cover the lesion, there are some disadvantages: the skin graft is vulnerable, the coverage area is limited due to size, and the freedom of transfer is inadequate [9]. Moreover, the final result is cosmetically unpleasing [6]. In addition, because the w o u n d cannot be closed tightly, this might lead to prolonged postoperative drainage and infection. Local fasciocutaneous flaps do not have e n o u g h freedom for
Fig. 2. Case 3: a 48-year-old man. (A) Preoperative view; there is scar formation on the medial side of the right knee. (B) The flap is 13 cm long and 7 cm wide. A dot in the flap marks the perforator branch of the peroneal artery. (C) The scar is replaced by the pedicle peroneal flap.
TKA Covered With Pedicle Peroneal Flap
transfer because the pedicle is short and wide. Hence, the indication of the fasciocutaneous flap is limited. A n o t h e r m e t h o d to replace scar tissue is to use the tissue expander on the neighboring skin. The tissue e x p a n d e r is usually used in h e a d and neck cases w h e r e the skin has rich blood supply and good elasticity; however, the skin a r o u n d the k n e e is less elastic and difficult to expand. Use of tissue expanders in the leg has b e e n reported but this procedure requires long preoperative expansion [11 ]. The p e r o n e a l flap is c o m m o n l y used to cover skin defects in the l o w e r leg [12,13]. The pedicle p e r o n e a l flap has m a n y advantages in covering TKA prostheses. First, this p r o c e d u r e is not a free tissue flap; m i c r o s u r g e r y is not necessary, operative time is relatively short (average operative time, 3.5 h o u r s in the three cases), and postoperative care is simple (no particular postoperative protocol). Second, the p e r o n e a l flap is usually large e n o u g h to c o v e r the k n e e area; h o w e v e r , if the skin defect is too extensive, for e x a m p l e , in t u m o r resection, free tissue transfers w o u l d still be n e e d e d [14,15]. Areas requiring skin flaps are usually scars t h a t w e r e f o r m e d o v e r b o n y p r o m i n e n c e s a r o u n d the knee. These areas include the patella, the m e d i a l a n d lateral condyles, a n d the tibial tuberosity. As the m a x i m u m size of the pero n e a l flap is a b o u t 17 c m long a n d 14 cm wide [13], the flap is usually sufficient in size. Third, the vascular pedicle of the peroneal flap is rather long with little anatomic variations [16]. This enables the flap to h a v e a wide freedom of transfer and the procedure itself is not complicated. The perforator b r a n c h f r o m the peroneal artery to the skin m u s t be identified with a Doppler f l o w m e t e r before designing the flap. Skin should be raised along the posterior border of the design to expose the perforating branch that is coming f r o m the s e p t u m b e t w e e n the peroneus longus a n d gastrocnemius muscle. The perforating branch is exposed to the branchpoint f r o m the peroneal artery and vein that r u n along the fibula. The distal ends of the peroneal vessels are ligated and cut, and the pedicle is elevated along the course of the peroneal vessels proximally. Tile peroneal vessels join the posterior tibial vessels at the popliteal region. The length of the p e d i d e depends on w h e r e this division is. Fourth, as the contralateral limb is not used as a d o n o r site, the patient can easily a m b u l a t e using the contralateral limb after the operation. Last, because this flap does n o t sacrifice muscles like the gastrocnemius muscle flap, there is less postoperative disability. Pedicle p e r o n e a l flap has b e e n d e m o n s t r a t e d to be a valuable t e c h n i q u e for soft tissue coverage
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a r o u n d the knee. With the increasing n u m b e r of TKAs, pedicle p e r o n e a l flaps can be used b o t h before a n d after TKA to p r e v e n t p o o r w o u n d healing.
Acknowledgments The a u t h o r thanks Dr. Hashiba, C. D. Nichols, and B e n j a m i n Ma for assistance in presenting part of this study a n d in completing this study.
References l. Scuderi GR: Total knee arthroplasty. Clin Orthop 276:26, 1992 2. Wilson MG: Infection as a complication of total knee-replacement arthroplasty. J Bone Joint Surg 72A:878, 1990 3. Gordon SM: Risk factors for wound infections alter total knee arthroplasty. Am J Epidemol 131:905, 1990 4. Windsor RE: Management of total knee arthroplasty infection. Orthop Clin North Am 22:531, 1991 5. Burger RR: Implant salvage in infected total knee arthroplasty. Clin Orthop 273:105, 1991 6. Sanders R: The gastrocnemius myocutaneous flap used as a cover for the exposed knee prosthesis. J Bone Joint Surg 63B:383, 1981 7. Greenberg B: Salvage of jeopardized total-knee prosthesis: The role of the gastrocnemius muscle flap. Plast Reconstr Surg 83:85, 1989 8. Browne EZ: The use of muscle flaps for salvage of failed total knee arthroplasty. Br J Plast Surg 47:42, 1994 9. Gerwin M: Gastrocnemius muscle flap coverage of exposed or infected knee prostheses. Clin Orthop 286:64, I993 10. Hallock GG: Salvage of total knee arthroplasty with local fasciocutaneous flaps. J Bone Joint Surg 72A: 1236, 1990 1 l. Serra JM: Use of calf prosthesis and tissue expansion in aesthetic reconstruction of the leg. Plast Reconstr Surg 89:684, 1992 12. Yoshimura M: Peroneal flap for reconstruction in extremity: preliminary report. Plast Reconstr Surg 74:402, 1984 13. Yoshimura M: Peroneal island flap for skin defects in the lower extremity. J Bone Joint Surg 67A:935, 1985 14. Ikeda K: Use of latissimus dorsi flap for reconstruction with prostheses after tumor resection. Microsurgery 15:73, 1994 15. Lesavoy MA: Muscle-flap coverage of exposed endoprostheses. Plast Reconstr Surg 83:90, 1989 16. Yoshimura M: The vasculature of the peroneal tissue transfer. Plast Reconstr Surg 85:917, 1990
Case Report
Total Knee Arthroplasty Covered With Pedicle Peroneal Flap Kazuo Ikeda, MD, Yutaka Morishita, Eiji S h i m o z a k i ,
MD, Tadami Matsumoto,
MD, Akira Nakatani, MD, and Katsuro
MD,
Tomita, MD
Abstract: Three cases of total knee arthroplasty (TICA) covered with pedicle peroneal flaps are reported. One peroneal flap was performed after TKA to correct postTKA skin necrosis. Two peroneal flaps were performed before TKA to replace previous traumatic scar formed around the knee. All three TKAs were successful after the procedure. The thickness, elasticity, appearance, and durability of the peroneal flaps were more suitable for the skin around the knee than the gastrocnemius muscle flap or the local fasciocutaneous flap. As the peroneal flap was elevated as a pedide flap, freedom of transfer was good, microanastomosis was not necessary, and no donor sites were needed from the contralateral limb. Scar tissue around the knee can be effectively replaced by the pedicle peroneal flap before TKA. Key words: total knee arthroplasty, peroneal flap, infection, scar tissue, complication.
Case Reports
As m o d e r n design and technique of total knee arthroplasty (TKA) advance, the indications for this procedure h a v e increased year after year; however, complication rates h a v e also increased. The worst complication of TKA is infection. Infection rates after TKA have b e e n reported as 0.63% [1], 1.6% [2], 8.2% [3], a n d 1.2 to 12.4% [4]. A fairly freq u e n t cause of infection post-TIC¢ has b e e n skin necrosis. About 62% of infected TIC_As have had a history of prolonged postoperative drainage with failure of p r i m a r y w o u n d healing [5]. Preoperative skin condition a r o u n d the knee is also e x t r e m e l y important. Poor blood circulation and preoperative scar formation w o u l d hinder w o u n d healing. The following are three cases of TKA covered with pedicle peroneal flap that has salvaged or p r e v e n t e d skin necrosis (Table 1).
Case 1 A 53-year-old w o m a n c o m p l a i n e d of right knee pain. She h a d sustained an o p e n fracture of her right distal f e m u r complicated by osteomyelitis 30 years earlier. There was a large scar that e x t e n d e d f r o m the anterior to the lateral side of the right knee. During the operation, skin over the k n e e was handled with e x t r e m e care. As the patella could not be t u r n e d over secondary to contracture, the tibial tuberosity was elevated and fixed using screws after i m p l a n t a t i o n of prosthesis. Necrosis of the lateral edge of the incision was n o t e d on postoperative day 3 and d e m a r c a t i o n was clear o n postoperative day 10 (Fig. 1A); however, there was no sign of infection. Two weeks after the initial operation, we debrided the lesion a n d p e r f o r m e d a pedicle p e r o n e a l flap for soft tissue coverage. We designed a p e r o n e a l flap 15 cm long and 4.5 cm wide f r o m the ipsilateral leg, and the perforator f r o m the p e r o n e a l artery to the flap was identified
From the Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, Kanazawa, Japan. Reprint requests: Kazuo Ikeda, MD, Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920, Japan.
478
TKA Covered With Pedicle Peroneal Flap
•
Ikeda et al.
479
Table 1. Characteristics of Three TICA Cases
Case 1 Age (years)/Sex Operations Follow-up period (years) Previous injury Length of pedicle (cm) Size of flap (cm) Location of flap
53/F Flap 3 weeks after TKA 2.5 Open fracture of the right distal femur complicated by osteomyelitis 30 years earlier 12 15 x 4.5 Top of patella
b y a D o p p l e r f l o w m e t e r (Fig. 1B). The flap was elev a t e d as a pedicle t h a t i n c l u d e d the p e r o n e a l a r t e r y a n d vein. The l e n g t h of the pedicle w a s 12 c m a n d long e n o u g h to be transferred to the lesion. Necrotic tissue o v e r the k n e e w a s c o m p l e t e l y resected. After resection, the prosthesis w a s exposed. The flap w a s passed t h r o u g h a t u n n e l u n d e r the skin a n d s u t u r e d using w a t e r t i g h t techn i q u e to c o v e r the prosthesis (Fig. 1C). The d o n o r site was t h e n c o v e r e d w i t h a split-thickness skin graft h a r v e s t e d f r o m the ipsilateral i n g u i n a l area. For the p u r p o s e of w o u n d control, the right l o w e r e x t r e m i t y was splinted a n d elevated for 7 days. D u r i n g this period, the p a t i e n t w a s a l l o w e d to a m b u l a t e w i t h a wheelchair. Physical t h e r a p y a n d r a n g e - o f - m o t i o n exercises w e r e started o n p o s t o p -
Case 2
Case 3
78tF TKA 3 months after flap 1.5 Trauma on the left tibial tuberosity during childhood
48/M TKA 3 months after flap 1.0 Open fracture dislocation of the right knee during childhood
10 9x 6 Lateral of final tuberosity
15 13 x 7 Medial of femoral condyle
erative d a y 7 a n d w e i g h t b e a r i n g w a s p e r m i t t e d o n p o s t o p e r a t i v e day 10. P o s t o p e r a t i v e r e c o v e r y w a s u n e v e n t f u l . The p a t i e n t has b e e n f o l l o w e d for 2.5 years. D u r i n g the interim, t h e r e w e r e n o signs of infection, a n d the flap w a s intact a n d cosmetically appealing. Case 2
A 7 8 - y e a r - o l d w o m a n c o m p l a i n e d of left k n e e pain. There was a large scar a n t e r i o r a n d lateral o v e r the tibial tuberosity, s e c o n d a r y to t r a u m a sustained during childhood. Poor postoperative w o u n d healing w a s anticipated f r o m o u r e x p e r i e n c e w i t h case I. R e p l a c e m e n t of extensive scar tissue w i t h a pedicle p e r o n e a l flap w a s p l a n n e d before TKA.
Fig. 1. Case i: a 53-year-old woman. (A) Ten-day postoperative view; the lateral skin edge of the incision is necrotic. (B) Design of the pedicle peroneal flap. The flap is 15 cm long and 4.5 cm wide. A dot in the flap marks the perforator branch of the peroneal artery, which is identified using a Doppler flowmeter. (C) The necrotic tissue is replaced by the pedicle peroneal flap passed through the tunnel under the skin.
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The Journal of Arthroplasty Vol. 11 No. 4 June 1996
pedicle peroneal flap 9 cm long a n d 6 cm wide f r o m the left leg was designed. The length of the pedicle was 10 cm. As the scar was inferior to the patella, a shorter pedicle w o u l d be sufficient. The scar was excised a n d the flap was passed t h r o u g h a tunnel u n d e r the skin to reach the lesion. The older age of the patient did not m a k e the procedure itself or the postoperative care m o r e complicated. Complete w o u n d healing and full recovery of muscle strength w e r e acheived before the left TIC_A, w h i c h was p e r f o r m e d 3 m o n t h s after the initial operation. The incision for the TKA was placed t h r o u g h the flap but there was no postoperative skin necrosis. The patient has b e e n followed for 1.5 years, and the flap has b e e n in excellent condition.
Case 3 A 4 8 - y e a r - o l d m a n c o m p l a i n e d of right k n e e pain. There was a large scar o n the m e d i a l side of the k n e e (Fig. 2A), s e c o n d a r y to an o p e n fracture dislocation of the right k n e e during childhood. As the p a t i e n t has extensive scar f o r m a t i o n , a pedicle p e r o n e a l flap was p l a n n e d before the TKA. A pedicle p e r o n e a l flap 13 c m long a n d 7 cm wide f r o m the right leg was designed (Fig. 2B). The length of the pedicle was 15 cm a n d was sufficient to r e a c h the opposite side of the leg. The flap was passed t h r o u g h a skin t u n n e l created o v e r the popliteal area to c o v e r the excised lesion (Fig. 2C). A posterior transfer was chosen, as an anterior transfer w o u l d h a v e placed the pedicle u n d e r
the incision for the later TKA. The d o n o r site was covered w i t h a split-thickness skin graft. Full a m b u l a t i o n was p e r m i t t e d on p o s t o p e r a t i v e day 7. A TKA was p e r f o r m e d 3 m o n t h s after the initial operation. R e c o v e r y was u n e v e n t f u l . The patient has b e e n followed up for a y e a r a n d e x p e r i e n c e d no complications.
Discussion Total knee arthroplasty was successful in salvaging and preventing poor w o u n d healing. Preoperative scar or necrotic tissue a r o u n d the knee was replaced using pedicle peroneal flaps after TKA (1 case) or before TKA (2 cases). If there is scar formation a r o u n d the knee joint due to previous t r a u m a or surgery, infection rate increases [2]. Skin necrosis occurs at a high incidence w h e n previous scar tissue is incised or elevated. Incidence increases w h e n the scar is thin and a d h e r e n t to the bone. In such cases, previous studies have reported using gastrocnemius muscle flap with skin graft [6-9] or a local fasciocutaneous flap [10]. Although the muscle flap can cover the lesion, there are some disadvantages: the skin graft is vulnerable, the coverage area is limited due to size, and the freedom of transfer is inadequate [9]. Moreover, the final result is cosmetically unpleasing [6]. In addition, because the w o u n d cannot be closed tightly, this might lead to prolonged postoperative drainage and infection. Local fasciocutaneous flaps do not have e n o u g h freedom for
Fig. 2. Case 3: a 48-year-old man. (A) Preoperative view; there is scar formation on the medial side of the right knee. (B) The flap is 13 cm long and 7 cm wide. A dot in the flap marks the perforator branch of the peroneal artery. (C) The scar is replaced by the pedicle peroneal flap.
TKA Covered With Pedicle Peroneal Flap
transfer because the pedicle is short and wide. Hence, the indication of the fasciocutaneous flap is limited. A n o t h e r m e t h o d to replace scar tissue is to use the tissue expander on the neighboring skin. The tissue e x p a n d e r is usually used in h e a d and neck cases w h e r e the skin has rich blood supply and good elasticity; however, the skin a r o u n d the k n e e is less elastic and difficult to expand. Use of tissue expanders in the leg has b e e n reported but this procedure requires long preoperative expansion [11 ]. The p e r o n e a l flap is c o m m o n l y used to cover skin defects in the l o w e r leg [12,13]. The pedicle p e r o n e a l flap has m a n y advantages in covering TKA prostheses. First, this p r o c e d u r e is not a free tissue flap; m i c r o s u r g e r y is not necessary, operative time is relatively short (average operative time, 3.5 h o u r s in the three cases), and postoperative care is simple (no particular postoperative protocol). Second, the p e r o n e a l flap is usually large e n o u g h to c o v e r the k n e e area; h o w e v e r , if the skin defect is too extensive, for e x a m p l e , in t u m o r resection, free tissue transfers w o u l d still be n e e d e d [14,15]. Areas requiring skin flaps are usually scars t h a t w e r e f o r m e d o v e r b o n y p r o m i n e n c e s a r o u n d the knee. These areas include the patella, the m e d i a l a n d lateral condyles, a n d the tibial tuberosity. As the m a x i m u m size of the pero n e a l flap is a b o u t 17 c m long a n d 14 cm wide [13], the flap is usually sufficient in size. Third, the vascular pedicle of the peroneal flap is rather long with little anatomic variations [16]. This enables the flap to h a v e a wide freedom of transfer and the procedure itself is not complicated. The perforator b r a n c h f r o m the peroneal artery to the skin m u s t be identified with a Doppler f l o w m e t e r before designing the flap. Skin should be raised along the posterior border of the design to expose the perforating branch that is coming f r o m the s e p t u m b e t w e e n the peroneus longus a n d gastrocnemius muscle. The perforating branch is exposed to the branchpoint f r o m the peroneal artery and vein that r u n along the fibula. The distal ends of the peroneal vessels are ligated and cut, and the pedicle is elevated along the course of the peroneal vessels proximally. Tile peroneal vessels join the posterior tibial vessels at the popliteal region. The length of the p e d i d e depends on w h e r e this division is. Fourth, as the contralateral limb is not used as a d o n o r site, the patient can easily a m b u l a t e using the contralateral limb after the operation. Last, because this flap does n o t sacrifice muscles like the gastrocnemius muscle flap, there is less postoperative disability. Pedicle p e r o n e a l flap has b e e n d e m o n s t r a t e d to be a valuable t e c h n i q u e for soft tissue coverage
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a r o u n d the knee. With the increasing n u m b e r of TKAs, pedicle p e r o n e a l flaps can be used b o t h before a n d after TKA to p r e v e n t p o o r w o u n d healing.
Acknowledgments The a u t h o r thanks Dr. Hashiba, C. D. Nichols, and B e n j a m i n Ma for assistance in presenting part of this study a n d in completing this study.
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