USE OF BIOABSORBABLE IMPLANTS FOR HALLUX VALGUS SURGERY

USE OF BIOABSORBABLE IMPLANTS FOR HALLUX VALGUS SURGERY

 Avilov S.M., Gorodnichenko A.I.

 Central State Medical Academy, Moscow, Russia

Hallux (abducto) valgus is the most common term in the literature. It designates any deformations at the level of the medial metatarsophalangeal articulation with valgus declination of the toe in most cases [1].
There is an interesting fact about absence of clear absolute signs for precise determination of the border between the normal value and the valgus declination of the toe, but the values above 15 degrees for the first metatarsophalangeal articulation (hallux valgus angle, HVA) or more than 9 degrees for the first intermetatarsal angle are considered as pathologic. However there are individuals with higher values of the first metatarsophalangeal and intermetatarsal angles, but without symptoms of hallux valgus [2].
Due to absence of any clear criteria determining the disease, it is quite difficult to estimate the incidence of the pathology in the population. According to some authors, it varies from 19 to 70 % [1-3].
The difficulty of pathogenesis of development of the disease requires the differential approach and estimation of direction of medical measures. Some priority directions for treating his pathology have appeared. They can be divided into conservative and surgical, but there is not any uniform opinion about features and volume of radical treatment [3].
Conservative treatment is based on slowing down progression of the pathologic process in the foot and is the method of choice for patients who request medical care for hallux valgus for the first time [4]. It is oriented to decreasing non-fixed valgus deformation, expansion of wrinkled soft tissues around the joint with use of night time splints, and increasing muscular tone of the foot with use of exercises, as well as wearing the orthopedic soles [5]. Juriansz (1996) conducted the randomized study including the patients with night splinting and the patients without treatment. There was not any significant difference in valgus declination, the value of the first intermetatarsal angle and pain intensity between the groups [6]. A similar randomized study of functional orthoses was conducted by Kilmartin et al. (1994). It included 122 children (age of 9-10). Three years later, the examination identified a statistically significant difference in the angle of valgus deformation in the study group [7]. Most researchers concluded that the conservative techniques were inefficient for adults [1, 2, 8].
Since the ancient times the surgeons paid their attention to the pathology of the first metatarsophalangeal articulation. In 1267 Theodorice wrote: “firstly, it is necessary to remove everything around and then to cauterize the spur”. In 1862 Boyer recommended ablation of a cyst in the first metatarsophalangeal articulation. In 1873 Fricke described two cases with round exostoses on the foot. He resected the bones forming the first metatarsophalangeal articulation and received the excellent results. The results of resection of the first metatarsophalangeal articulation were published by Pancoast in 1844 and Hilton in 1853. In 1874 Rose removed the sesamoid bones as a part of joint resection. Reverdin (1881) advocated only removal of exostoses. In 1904 Keller initiated resections of the basis of the proximal phalanx of the toe [1, 8].
In the 20th century the number of operations for correcting hallux valgus increased significantly. Metcalf (1912) summarized 15 different types of surgery, Timmer (1930) described 25 types, Verbrugge (1933) – 51, Perrot (1946) – 68. For the moment of 1990 about 150 various types of surgery (Luthje, 1990) were described. At the present time there are about 400 surgical techniques for static deformations of the anterior part of the foot [9, 10]. The significant amount of surgical techniques indicates the absence of a uniform technique and presence of serious disadvantages. For achievement of good functional outcomes the choice of a surgical technique should depend on the anatomical features and the basics of pathological changes in a patient [2, 8].
For selecting a surgical technique one can use a lot of the classifications, which are based on the various principles: anatomical principle (soft tissues of bones), a type of surgical intervention, surgery localization. The selected technique must correct all elements of deformation: osteophyte of the head of the first metatarsal bone, valgus deformation of the proximal phalanx of the toe, increase in the first intermetatarsal angle, congruity of articular surfaces, subluxation of sesamoid bones and toe pronation [9].
Some types of osteotomy of the first metatarsal bone became popular. The offered techniques include diaphysis and metaphysis osteotomy (the proximal and distal ends of the first metatarsal bone). They are different according to the direction of osteotomy line [10, 11, 12].
Regardless of choice of osteotomy type, fixation is performed with various metal constructs. The analysis of the complications after osteotomy of the first metatarsal bone showed that the significant proportion of the complications was associated with metal implants. Metal implants provide proper fixation of bone fragments, but rigidity of fixation is excessive and it leads to osteolysis on the border between metal and the bone (stress-shielding syndrome) and migration of metal constructs [13, 14, 15]. According to the data from many researchers, this event is associated with diverse elasticity of bone tissue and metal (Young 's modulus – 10-30 GPa for the cortical bone and 100-200 GPa for metal). The second disadvantage of metal fixators is need for recurrent surgery after its removal [16].
Owing to the high incidence in the population, the pathology has both medical and economical meaning. Therefore, the researchers have been trying to improve the outcomes of surgical treatment, to reduce hospital stay and to decrease the costs of treatment. The surgical techniques and the methods of fixation of the first metatarsal bone after osteotomy have been improving [17].
The “ideal” fixator for osteotomy should provide the adequate stability of bone fragments, have sufficient strength up to the moment of full union and absorption after union, with excluding the necessity of recurrent surgery for removal of the fixator [18].

History of biodegradable materials

α-polyhydroxyacids is a class of synthetic ester polymers of α-hydroxyacids. The most common types of this class are polylactic and polyglycolic acids.
Bischoff and Walden synthesized polyglycolic acid (PGA) in 1893. Its high-molecular polymer with elastic properties was synthesized by Higgins in 1954. It became the first absorbing suture material. The polymers of glycolic acid are solid crystal compounds, insoluble in fluid, with the melting temperature of 224-228°C [20]. Biodegradation of complex polyesters is realized by means of non-specific hydrolytic breakdown to carbon dioxide and water [21]. The time of absorption depends on the environment conditions, molecular mass and the implant size. Mechanical strength of PGA disappears after 4-7 weeks, and full absorption of the polymer takes place in 6-12 months (from 12 weeks to 9 months according to the various authors) [22]. According to Vasenius (1990), PGA is the strength material with rigidity, which is sufficient for fixation of most fractures. However because of hygroscopicity, degradation of the polymer is too rapid [23]. Because of fast degradation and development of aseptic synuses, the implants made of “clear” PGA are not used for osteosynthesis [24].
The polymers of lactic acid (polylactides, PLA) are hemicrystalline and hydrophobic. PLA consists of recurrent links of lactic acid, with two stereoisomeric forms of L and D-isomers. L-isomer originates in the human body, for example, as result of anaerobic metabolism of glucose. The level of D-isomer in the body is extremely low. L-isomer is characterized by high mechanical strength and low absorption. Therefore, it is used for production of orthopedic implants. The high-molecular synthetic polymer of lactic acid with thermoplastic properties was created by Schneider in 1955. As compared to other PGA biodegradable implants, poly-L-lactic acid (PLLA) polymers have longer period of degradation (2-6 years) [25, 26]. Degradation of polylactide is caused by non-enzymatic hydrolysis with breakdown to pyruvate. The time of degradation depends on the ratio of polymers in the implant, solidity and molecular weight and it lasts for 9.3 years according to Voutilainen et al. (2002) [27]. The advantages and the disadvantages of each polymer resulted in development of the copolymer implants including L- and D-isomer of lactic acid. The rate of absorption and mechanical strength depend on the quantitative level of various isometric forms of L- and D-monomers in the polymer chain. The strength of PLA copolymers can be significantly increased by mixing with absorbable rubbers such as trimethylene capronate [28].
Biodegradable polymers were firstly mentioned in the literature in the end of 1960s. In 1966 Kulkarni et al. published the report about biocompatibility of L-polylactide (LPLA) in the animals. Polymer was implanted in guinea pigs and rats. The powder form was used. The researchers found that the polymer was non-toxic, without responses in surrounding tissues and with long period of degradation. In 1971 the researchers presented the animal study of biodegradable plates and screws made of the same polymer (LPLA) for fixation of fractures of the lower mandible [28]. At the same time, Cutright et al. published the similar study [29]. Both studies showed that the material did not cause inflammation or response to a foreign body, although absorption was not complete in the end of the study. In 1984 Rokkanen et al. were the first who had used biodegradable implants for fixation of the ankle join in the human (Helsinki, Finland) [30].
Currently, PLA and PGA copolymers, i.e. polylactide-glycolide (PLGA), are used. Bioabsorbable implants have some important advantages as compared to metal implants, for example, gradual increase in load to a healing bone (while degradation of polymer continues) and absence of necessity for removal of the fixator [31]. According to the analysis of Cochrane database (Jainandunsing et al., 2009), there were no statistically significant differences between biodegradable implants and other implants concerning long term results, functional status and complications [32]. The percentage of recurrent surgery is lower for use of these fixators as compared to other groups. The authors concluded that fixation of simple fractures (type A) with biodegradable implants was an appropriate technique of treatment with low rate of complications and 20 % decrease in costs [33].
Some authors state that the biomechanical properties of bioabsorbable screws and plates are similar with metal ones, if used for small tubular bones [34], others believe that bioabsorbable implants have lower mechanical strength and torsion stability as compared to metal [35] that is the advantage for fixing fractures with small fragments, fixation of arthrodesis of small joints, osteotomy of small bones and fixation of ligamentous and soft tissue structures of the humeral and knee joints.

The results of use of bioabsorbable materials for fixation of the first metatarsal bone

The first reports about use of absorbable fixators for correction of hallux valgus described the complications after use: development of granuloma around the implant, soft tissue response, loss of mechanical stability of the implant and lost correction of the first metatarsal bone [36-38]. But the problem of osteolysis was still actual, although bioabsorbable materials were initiated for elimination of this problem. Burns et al. identified the radiological signs of osteolysis in more than 22 % of operated patients, but it did not influence on the functional outcome [39].
There were reports about efficient use of biodegradable screws. Brunetti VA et al. described a single case with use of bioabsorbable screws for fixation of chevron osteotomy with satisfactory outcomes [40].
Along with search of optimal ratio of polymers and improvement in bioabsorbable implants, the researchers reported about the satisfactory results. Hirvensalo et al. produced 78 procedures of chevron osteotomy of the first metatarsal bone and fixation with PGA screws. In 75 % of the cases the results were excellent and good, but 15 % of the patients complained of pain in the first metatarsophalangeal joint during load, and in 10 % - recurrent deformation [35]. Other authors also reported about the positive results of use of biodegradable implants [41-49].
DeOrio and Ware described the results of fixation with use of polydioxanone pins and achieved the satisfactory level of correction. Moreover, there were no such complications as osteolysis, infection, aseptic necrosis of the femoral head or non-union of osteotomy [46].
 Winemaker et al. compared the results of fixation with pins and bioabsorbable screws. The functional index AO FAS was similar in two groups. Pin fixation resulted in complications in 4 patients among 21, with no complications in other group [47].
Barca et Busa conducted 35 procedures of chevron osteotomy with PLA screw fixation. Stable fixation and normal postsurgical bone union were noted in all cases. 90 % of the patients reported about satisfactory functional and cosmetic results. One case was complicated by aseptic necrosis of the head of the metatarsal bone [48]. Surrounding tissue response exists in use of metal fixators and bioabsorbable ones, with manifestations in view of granuloma, sterile sinus, osteolysis and fibrous alteration of tissues around the implant.
Morandi A (2013) published the results of use of bioabsorbable screws for fixation of chevron osteotomy (439 operations for 5 years). The authors concluded that use of polymer screws resulted in good clinical and radiological outcomes (also long term results within 5 years) and the low number of complications [45].
Besides the medical aspects of bioabsorbable screws, some economical issues exist.   Valletjo-Torres L et al. (2011) conducted the study of economical efficiency of bioabsorbable screws as compared to metal ones. They concluded that despite of increasing costs for production of such implants, the final costs for treating one patient decrease due to absence of necessity for recurrent surgery for removal of the fixator [50, 51].

FINAL STATEMENT

Therefore, the analysis of the foreign and domestic literature showed the absence of any uniform opinion about bioabsorbable materials for correction of hallux valgus.
Some authors consider that efficiency and reliability of polymers are similar with metal fixators with low rate of complications. Other researchers state that polymers are fragile and osteolysis develops around the implant, as well as granuloma appears.
The biomaterials have been improving during the last 50 years. In the modern biodegradable implants the percentage ratio of polymers of lactic and glycolic acids is optimal for stable fixation of the bone and degradation of polymer after osteotomy union.
The economic aspect is also discussed. From one side, production of polymers is the expensive high-tech process that influences on the final price of the implant. From other side, there is no need for removal of the implant, i.e. no recurrent admission and decreasing costs for treating one patient.
Considering the above-mentioned facts, the actual issue exists: a possibility for use of the modern bioabsorbable fixators instead of standard metal ones, the influence on the functional status and quality of life in patients with hallux valgus.

CONCLUSION

1. The modern bioabsorbable implants demonstrate the sufficient strength for fixation of bone tissue with degradation of polymer after union of osteotomy of the first metatarsal bone.
2. The characteristics of rigidity of bone tissue and biopolymers are similar. As result, stress-shielding syndrome does not develop.
3. The economic appropriateness of biodegradable implants is not estimated: the production is expensive, but there is no need for removal of the fixator.
4. The rate of complications after use of biodegradable implants and metal ones is similar for fixation of osteotomy of the first metatarsal bone.
5. There are not any studies concerning the quality of life after correcting osteotomy of the first metatarsal bone with use of biodegradable implants.

REFERENCES

1.      Kardanov A. The schemes and the pictures of surgery of the anterior part of the foot. Medpractica. M., 2012. P. 20-25. Russian (Карданов А. Хирургия переднего отдела стопы в схемах и рисунках. Медпрактика. М, 2012. С. 20-25.)
2.      Hetherington V. Hallux valgus and forefoot surgery. Churchill Livingstone, 1994. 582 p.
3.      Lyabakh AP, Zazirny IM, Semeniv IP, Rudenko RI. Etiology and pathogenesis of Hallux valgus (literature review). Herald of Orthopedics, Traumatology and Prosthetics; 2013. 3 (78): 70-72. ( Russian (Лябах А.П., Зазирный И.М., Семенив И.П., Руденко Р.И. Этиология и патогенез Hallux valgus (Обзор литературы) // Вісник ортопедії, травматології та протезування. 2013. № 3 (78). С. 70-72.)
4.      Goleva AV. Hallux valgus. Zemsky Vrach; 2010. 2: 22-24. Russian (Голева А.В. Hallux valgus // Земский врач. 2010. № 2. С. 22-24.)
5.      Ferrari J, Higgins JPT, Williams RL. Interventions for treating hallux valgus (abductovalgus) and bunions (Cochrane Review). The Cochrane Library. 2000. Issue 1. Oxford: UpdateSoftware
6.      Juriansz AM. Conservative treatment of hallux valgus: a randomized controlled clinical trial of a hallux valgus night splints (M.Sc. thesis). King’s College, London University, London 1996
7.      Kilmartin TE, Barrington RL, Wallace WA. A controlled prospective trial of a foot orthosis for juvenile hallux valgus. J Bone Joint Surg Br. 1994; 76: 210-214
8.      Protsko VG. Choice of optimal treatment technique for Hallux valgus : dissertation of candidate of medical science / Peoples' Friendship University of Russia. M., 2004. 124 p. Russian ( Процко В.Г. Выбор оптимального метода лечения вальгусной деформации первого пальца стопы : дисс. канд. мед. наук / Российский университет дружбы народов. М., 2004. 124 с.)
9.      Tertyshnik SS. Surgical treatment of deformations of the anterior part of the foot in Hallux valgus: dissertation of candidate of medical science / Russian Scientific Center “Reconstructive Traumatology and Orthopedics”. Kurgan, 2011. 144 p. Russian (Тертышник С.С. Оперативное лечение деформаций переднего отдела стопы при Hallux valgus: дис. … канд. мед. наук / ФГУН "Российский научный центр "Восстановительная травматология и ортопедия". Курган, 2011. 144 с.)
10.     Kim AD, Kim DS. The methods for correction of hallux valgus. In: Herald of the Public Organization “the Association of Surgeons of Irkutsk Region”: the materials from 20th meeting of the Association of Surgeons of Irkutsk Region, April 26, 2013. Irkutsk: Scientific Center of Reconstructive Surgery of Siberian department of Russian Academy of Medical Science, 2013. P. 153-155. (Ким А.Д., Ким Д.С. Способы устранения hallux valgus // Вестник Общественной организации «Ассоциация хирургов Иркутской области»: материалы XX съезда АХИО, 26 апреля 2013 г. Иркутск: НЦРВХ СО РАМН, 2013. С. 153-155
11.     Tertyshnik SS, Grekova NM, Pfeier AV, Atmanskiy IA, Astapenkov DS. Surgical correction of deformations of the anterior part of the foot in hallux valgus. Chelyabinsk: Elit-pechat publ., 2015. 158 p. Russian (Тертышник С.С., Грекова Н.М., Пфейфер А.В., Атманский И.А., Астапенков Д.С. Оперативная коррекция деформаций переднего отдела стопы при hallux valgus. Челябинск : Издательство Элит-печать, 2015. 158 с.
12.     Golovakha ML, Shishka IV, Banit OV, Babich YuA, Tverdovskiy AO, Zabelin IN. The results of treatment of Hallux valgus with use of CHEVRON-STEOTOMY. Orthopedics, Traumatology and Prosthetics. 2012; 3 (588) : 42-46. Russian (Головаха М.Л., Шишка И.В., Банит О.В., Бабич Ю.А., Твердовский А.О., Забелин И.Н Результаты лечения Hallux valgus с применением CHEVRON-ОСТЕОТОМИИ // Ортопедия, травматология и протезирование. 2012. № 3 (588). С. 42-46.)
13.     Bobrov DS, Slinyakov LYu, Yakimov LA, Khurtsilava ND. Shaft correcting osteotomy SCARF in treatment of foot deformations. Chair traumatology and orthopedics. 2012; (1): 16-19. Russian (Бобров Д.С., Слиняков Л.Ю., Якимов Л.А., Хурцилава Н.Д., Диафизарная корригирующая остеотомия SCARF в лечении деформаций стоп // Кафедра травматологии и ортопедии. 2012. № 1. С. 16-19.)
14.     Perren SM. Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology. J Bone Joint Surg Br. 2002; 84(8):1093-1110
15.     Uhthoff HK, Poitras P, Backman DS. Internal plate fixation of fractures: short history and recent developments. J Orthop Sci. 2006; 11(2):118-126
16.     Ambrose CG, Clanton TO. Bioabsorbable implants: review of clinical experience in orthopedic surgery. Ann Biomed Eng. 2004; 32 (1): 171-177
17.     Sorokin EP, Kardanov AA, Lasunskiy SA, Bezgodkov YuA, Gudz AI. Surgical treatment of hallux valgus and possible complications (literature review). Traumatology and Orthopedics of Russia. 2011; 4 (62): 123-130. Russian (Сорокин Е.П., Карданов А.А., Ласунский С.А., Безгодков Ю.А., Гудз А.И. Хирургическое лечение вальгусного отклонения первого пальца и его возможные осложнения (обзор литературы) // Травматология и ортопедия России. 2011. № 4 (62). С. 123-130.)
18.     Bezgodkov YuA, Al D. Improvement in surgical treatment of hallux valgus. Modern problems of science and education. 2015; (6-0): 194. Russian (Безгодков Ю.А., Аль Д. Совершенствование хирургического лечения hall ux valgus // Современные проблемы науки и образования. 2015. № 6-0. С. 194.)
19.     Schmitt EE, Polistina RA. Polyglycolid acid prosthetic devices: U.S. Patent. 1969. 3 463 158 edn.
20.     Williams DF. Biodegradation of surgical polymers. Journal of Materials Science. 1982; 17 (5): 1233-1246
21.     Vainionpää S, Kilpikari J, Laiho J, Helevirta P, Rokkanen P.U. Törmälä P. Strength and strength retention invitro, of absorbable, self-reinforced polyglycolide (PGA) rods for fracture fixation. Biomaterials. 1987; 8 (1) : 46-48
22.     Vert M, Christel P, Chabot F, Leray J. Bioresorbable plastic materials for bone surgery in Macromolecular biomaterials. Eds. G.W. Hastings & P. Ducheyne. CRC Press, Florida, 1984. P. 119-142
23.     Vasenius J, Vainionpää S, Vihtonen K, Mäkelä EA, Rokkanen PU, Mero M. et al. Comparison of in vitro hydrolysis, subcutaneous and intramedullary implantation to evaluate the strength retention of absorbable osteosynthesis implants. Biomaterials. 1990; 11 (7): 501-504
24.     Böstman OM, Hirvensalo E, Vainionpää S, Vihtonen K, Törmälä P, Rokkanen PU. Degradable polyglycolide rods for the internal fixation of displaced bimalleolarfractures. International orthopaedics. 1990; 14 (1): 1-8
25.     Nakamura T, Hitomi S, Watanabe S, Shimizu Y, Jamshidi K, Hyon SH, et al. Bioabsorption of polylactides with different molecular properties. J Biomed Mater Res. 1989; 23: 1115–1130
26.     Törmälä P, Pohjonen T,Rokkanen P. Bioabsorbable polymers: materials technology and surgical applications. Proc Inst Mech Eng H. 1998; 212 (2): 101-111
27.     Voutilainen NH, Hess MW, Toivonen TS, Krogerus LA, Partio EK, Pätiälä H. A long-term clinical study on dislocated ankle fractures fixed with self-reinforced polylevolactide (SR-PLLA) implants. Journal of long-term effects of medical implants. 2002; 12 (1): 35-52
28.     Kulkarni RK, Moore EG, Hegyeli AF, Leonard F. "Biodegradable poly (lactic acid) polymers". Journal of Biomedical Materials Research. 1971; 5 (3): 169-181
29.     Cutright DE, Hunsuck EE, Beasley JD. Fracture reduction using a biodegradable material, polylactic acid. Journal of oral surgery. 1971; 29 (6): 393-397
30.     Rokkanen PU, Böstman OM, Vainionpää S, Vihtonen K, Törmälä P, Laiho J, et al. Biodegradable implants in fracture fixation: early results of treatment of fractures of the ankle. Lancet. 1985; 1 (8443): 1422-1424
31.     Hanafusa S, Matsusue Y, Yasunaga T, Yamamuro T, Oka M, Shikinami Y, et al. Biodegradable plate fixation of rabbit femoral shaft osteotomies. A comparative study. Clin Orthop Relat Res. 1995; (315): 262-271
32.     Jainandunsing JS, van der Elst M, van der Werken C. WITHDRAWN: Bioresorbable fixation devices for musculoskeletal injuries in adults. Cochrane Database Syst Rev. 2009 Jan 21; (1): CD004324. doi: 10.1002/14651858.CD004324.pub3. Review
33.     Böstman OM, Pihlajamäki HK, Partio EK, Rokkanen PU. Clinical biocompatibility and degradation of polylevolactide screws in the ankle. Clinical orthopaedics and related research. 1995; (320): 101-109
34.     Weiler A, Helling H-J, Kirch U, Zirbes TK, Rehm KE. Foreign-body reaction and the course of osteolysis after polyglycolide implants for fracture fixation. Experimental study in sheep. J Bone Joint Surg Br. 1996; 78 (3): 369–376
35.     Hirvensalo E, Böstman OM, Törmälä P, Vainionpää S, Rokkanen PU. Chevron osteotomy fixed with absorbable polyglycolide pins. Foot Ankle. 1991; 11(4): 212-218
36.     Gerbert J. Effectiveness of absorbable fixation devices in Austin bunionectomies. J Am Podiatr Med Assoc. 1992; 82 (4): 189-195
37.     Miketa JP, Prigoff MM. Foreign body reactions to absorbable implant fixation of osteotomies. J Foot Ankle Surg. 1994; 33(6): 623-627
38.     Pavlovich R Jr, Caminear D. Granuloma formation after chevron osteotomy fixation with absorbable copolymer pin: a case report. J Foot Ankle Surg. 2003; 42(4): 226-9
39.     Burns AE. Biofix fixation techniques and results in foot surgery. J Foot Ankle Surg. 1995; 34(3): 276-282
40.     Brunetti VA, Trepal MJ, Jules KT. Fixation of the Austin osteotomy with bioresorbable pins. J Foot Surg. 1991; 30(1): 56-65
41.     Pihlajamäki H, Böstman O, Hirvensalo E, Törmälä P, Rokkanen P. Absorbable pins of self-reinforced poly-L-lactic acid for fixation of fractures and osteotomies. J Bone Joint Surg Br. 1992; 74(6): 853-857
42.     Hetherington VJ, Shields SL, Wilhelm KR, Laporta DM, Nicklas BJ., Absorbable fixation of first ray osteotomies. J Foot Ankle Surg. 1994. 33(3): 290-294
43.     Small HN, Braly WG, Tullos HS. Fixation of the Chevron osteotomy utilizing absorbable polydioxanon pins. Foot Ankle Int. 1995; 16 (6): 346-350
44.     Caminear DS, Pavlovich R Jr, Pietrzak WS. Fixation of the chevron osteotomy with an absorbable copolymer pin for treatment of hallux valgus deformity. J Foot Ankle Surg. 2005; 44(3): 203-210
45.     Morandi A, Ungaro E, Fraccia A, Sansone V. Chevron osteotomy of the first metatarsal stabilized with an absorbable pin: our 5-year experience. Foot Ankle Int. 2013; 34(3): 380-385
46.     Deorio JK, Ware AW. Single absorbable polydioxanone pin fixation for distal chevron bunion osteotomies. Foot Ankle Int. 2001; 22 (10): 832-835
47.     Winemaker MJ, Amendola A. Comparison of bioabsorbable pins and Kirschner wires in the fixation of chevron osteotomies for hallux valgus. Foot Ankle Int. 1996; 17(10): 623-628
48.     Barca F, Busa R. Austin/chevron osteotomy fixed with bioabsorbable poly-L-lactic acid single screw. J Foot Ankle Surg. 1997; 36(1): 15-20
49.     Vallejo-Torres L, Steuten L, Parkinson B, Girling AJ, Buxton MJ. Integrating health economics into the product development cycle: a case study of absorbable pins for treating hallux valgus. Med Decis Making. 2011; 31(4): 596-610
50.     Khoninov BV, Sergunin ON, Skoroglyadov PA. The analysis of clinical efficiency of use of biodegradable implants in surgical treatment of hallux valgus. Herald of Russian State Medical University. 2015; (3): 20-24. Russian (Хонинов Б.В., Сергунин О.Н., Скороглядов П.А. Анализ клинической эффективности применения биодеградируемых имплантов в хирургическом лечении вальгусной деформации 1 пальца стопы // Вестник Российского государственного медицинского университета. 2015. № 3. С. 20-24.)
51.     Leonova SN, Usoltsev IV. Use of biodegradable screws in treatment of patients with hallux valgus. Herald of East-Siberian scientific center of Surgical department of Russian Academy of Medical Science. 2016; 1 (4): 51-55. Russian (Леонова С.Н., Усольцев И.В. Использование биодеградируемых винтов при лечении пациентов с hallux valgus // Бюллетень Восточно-Сибирского научного центра Сибирского отделения Российской академии медицинских наук. 2016. Т. 1, № 4 (110). С. 51-55.)

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