Foot and Ankle Surgery 20 (2014) 20–25
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Foot and Ankle Surgery journal homepage: www.elsevier.com/locate/fas
Lengthening scarf osteotomy for recurrent hallux valgus Barry Rose MA, FRCS (Eng)*, Nicholas Bowman FRCS (Tr & Orth), Huw Edwards MB, BS, BSc, Samuel S. Rajaratnam FRCS (Tr & Orth), Andrew R. Armitage FRCS (Tr & Orth), Andrew D. Skyrme FRCS (Tr & Orth) Eastbourne District General Hospital, East Sussex, UK
A R T I C L E I N F O
A B S T R A C T
Article history: Received 26 June 2013 Received in revised form 6 August 2013 Accepted 22 August 2013
Background: We describe using the scarf osteotomy to correct a recurrent hallux valgus deformity and lengthen the shortened first metatarsal in symptomatic iatrogenic first brachymetatarsia. Methods: Thirty-six lengthening scarf osteotomies were undertaken in 31 patients. Clinical and radiographic measures were taken pre and postoperatively. Results: Mean age at presentation was 53.4 years, and mean followup 3.9 years. The mean lengthening achieved was 4.9 mm. All osteotomies united with no complications. The mean IMA reduction was 4.08 (p < 0.001) and HVA 13.08 (p < 0.001). The mean AOFAS score increase was 33.8 (p < 0.001). There was a positive trend but no correlation (r = 0.28) between amount of metatarsal lengthening and AOFAS score change. Conclusions: We describe the largest lengthening scarf osteotomy series for recurrent hallux valgus with iatrogenic first brachymetatarsia. The results suggest the procedure is successful, with a low complication rate. We anticipate that restoring first metatarsal length and alignment may reduce biomechanical transfer metatarsalgia over time. ß 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Hallux valgus Metatarsalgia Osteotomy Bone lengthening
1. Introduction A myriad of procedures have been described to surgically correct hallux valgus. There is a variable but significant recurrence risk following such surgery. Patients may present with a recurrence of their deformity, pain at the medial metatarsal eminence or transfer metatarsalgia [1]. Such symptoms may be the result of an iatrogenic first brachymetatarsia following the index surgical procedure. Shortening of the first metatarsal has been shown to correlate with the onset of transfer metatarsalgia [2–5], although many other causes of forefoot pain do exist. The scarf osteotomy has been popularised by Barouk in recent years as a technique for primary hallux valgus surgery [6]. This zstep carpentry term was originally described as a metatarsal osteotomy by Meyer in 1926 [7], but not widely used. It was redescribed in 1976 by Burutaran [8]. The z-step osteotomy is potentially a powerful surgical tool, allowing for correction of moderate to severe deformities. By altering the configuration of the bone cuts one can translate the metatarsal head in both the mediallateral (sagittal) as well as the plantar-dorsal (coronal) planes.
Furthermore, the osteotomy may enable rotation, to correct an increased distal metatarsal articulation angle (DMAA), and can facilitate shortening or lengthening of the metatarsal. It can therefore be used to address the first brachymetatarsia seen in some patients presenting with recurrent symptomatic hallux valgus or transfer metatarsalgia as a result of an iatrogenic shortened first ray [9]. Singh and Dudkiewicz [9] describe a prospective cohort series of 16 patients undergoing scarf osteotomy for metatarsalgia as a result of iatrogenic first brachymetatarsia following a Wilson’s osteotomy. The authors report good results with first metatarsal lengthening of at least 8 mm. Other evidence within the literature for the employment of the scarf osteotomy for this use is scanty. The purpose of this study therefore was to further assess the results of a lengthening scarf osteotomy in a prospective cohort of patients with symptomatic hallux valgus recurrence and iatrogenic first brachymetatarsia. We anticipate that restoring the length and alignment may reduce medial metatarsal eminence pain and lesser ray pain as a result of biomechanical transfer metatarsalgia over time. 2. Methods
* Corresponding author at: 18 Mereworth Road, Tunbridge Wells, Kent TN4 9PL, UK. Tel.: +44 7779620019. E-mail address: [email protected] (B. Rose).
A prospective cohort of patients was recruited from specialist foot and ankle clinics run by the senior author in three institutions
1268-7731/$ – see front matter ß 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fas.2013.08.004
B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25
between 2006 and 2010. All patients underwent clinical and radiographic assessment. All patients who had undergone previous hallux valgus bony surgery were considered. The nature of the surgery did not preclude inclusion. Patients were considered eligible for lengthening scarf osteotomy if they presented with recurrent hallux valgus and medial metatarsal eminence pain. They also required radiographic evidence of iatrogenic first brachymetatarsia (significant first metatarsal shortening from normal, judged using the ipsilateral lesser metatarsal arcade as a reference for the native first metatarsal length) (Fig. 1). Radiographs from prior to the index procedure were unavailable. The presence of transfer metatarsalgia (defined as pain felt under the lesser metatarsal heads, with or without associated plantar callosities) was noted from the history and examination. This was investigated as indicated by blood testing and further imaging to exclude other causes of pain including inflammatory arthropathy and interdigital neuromas. Excluded patients included: those skeletally immature individuals, those medically unfit for surgery and those with concurrent midfoot or hindfoot pathology, or previous midfoot or hindfoot surgery. A minimum of 12 months followup was necessary for inclusion. All patients were seen and assessed by the senior author (AS) preoperatively. Their symptoms were evaluated clinically using the American Orthopaedic Foot and Ankle Society (AOFOS) score [10] and the Short Form 12 (SF12) inventory [11]. Radiographic assessment of weight-bearing views measured the Hallux Valgus Angle (HVA) and Intermetatarsal Angle (IMA), standard measures of the severity and nature of hallux valgus (Fig. 2) [12]. All radiographs were made available from the hospital Patient Archiving Communication System (PACS). Angles were measured using the in-built PACS tools, and rounded to the nearest whole number. These measurements were performed for all radiographs by two independent observers (BR and NB), and repeated after an interval of two weeks, enabling the calculation of Pearson’s product moment correlation coefficient to assess inter and intraobserver reliability.
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Hospital-approved written clinical information leaflets were available to patients explaining the nature of surgery, including the postoperative course. All patients gave written informed consent for surgery. In all cases the senior author performed a scarf osteotomy with lateral translation and/or rotation of the distal fragment as part of the standard procedure. The osteotomy incorporated first metatarsal lengthening to re-establish the bone length by angling the z-step cuts distally, facilitating a gain in length when rotation and/or translation occurred. The length gain was predicted radiographically preoperatively and determined intra-operatively by the appearance and soft-tissue tension. The maximum planned lengthening was 10 mm. The actual gain in length was measured intra-operatively with callipers and a ruler. No attempt was made to plantarflex the first ray, which can theoretically be used to achieve a similar effect to lengthening the metatarsal. The remainder of the procedure followed the standard principles of hallux valgus surgery, including a complete lateral soft tissue release in all cases to ensure correct soft tissue tension and prevent postoperative stiffness at the metatarsophalangeal joint (MTPJ). The range of motion at the MTPJ was assessed prior to closure to ensure no inherent stiffness. Lesser metatarsal Weil osteotomies were undertaken as necessary solely to restore the arcade of the metatarsal heads, but not with the aim of achieving paradoxical first metatarsal lengthening. Symptomatic preoperative transfer metatarsalgia in itself was not an indication to perform Weil osteotomies. Any lesser toe procedures were undertaken concurrently. Postoperatively, patients were seen in our clinic as per standard postoperative protocol. Once full recovery had occurred, clinical assessment was undertaken with the AOFAS score and SF12 inventory re-performed, and the same radiographic measures repeated. Data was analysed using IBM SPSS Statistics Version 19 (IBM Corporation, Armonk, New York, USA). Categorical data were expressed as a number and continuous data as a mean. The differences between pre and postoperative radiographic results and AOFAS scores were assessed using paired sample t-tests. Pearson’s product moment correlation coefficient was calculated
Fig. 1. Example of pre and post-operative radiographs.
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B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25
Fig. 2. Example of pre and post-operative radiographs annotated to calculate IMA and HVA.
to determine the relationship between the amount of lengthening and the change in objective and subjective parameters. A p value of less than 0.05 was considered statistically significant. This study was performed within the confines of the Research Governance Framework and the 2008 Declaration of Helsinki [13,14]. 3. Results Thirty-one patients (28 female, three male) were identified and included in the cohort. Thirty-six lengthening scarf osteotomies were undertaken. No patient underwent simultaneous bilateral procedures. The mean age at presentation was 53.4 (range, 26–76) years. In all 36 cases, patients described recurrence of hallux valgus with pain at the medial metatarsal eminence, and in 20 cases, transfer metatarsalgia was also described. The mean time of revision surgery from the index surgical procedure was 10.0 (range, 1–31) years. The index procedures are summarised in Table 1. The mean followup was 3.9 (range, 1–5) years. Radiographic data was incomplete in seven cases (19%): two without preoperative imaging and five without postoperative imaging available. In four cases (11%) the AOFAS score was incomplete and in five cases (14%) the SF12 inventory was not completed, despite a minimum of three attempts to contact the individuals. This data was excluded from analysis.
Table 1 Breakdown of index procedure. Index surgical procedure
Number (percentage)
Wilson osteotomy Bunionectomy Chevron osteotomy Mitchell osteotomy Scarf osteotomy Unknown
17 11 3 3 1 1
(47%) (31%) (8%) (8%) (3%) (3%)
The mean first metatarsal lengthening achieved was 4.9 (range, 1–8) mm. There were 27 Akin osteotomies, and 24 lesser toe procedures, including Weil osteotomies in 16 cases. There was no significant difference (p = 0.07) between the length gained in the group undergoing concurrent Weil osteotomies (mean 5.4 mm), and the group without a lesser metatarsal osteotomy (mean 4.4 mm). There were no other pre or postoperative distinguishing features between these two groups, either clinical or radiographic. All osteotomies united clinically and radiographically. In no cases was there a loss of first MTPJ range of movement. There were no cases of infection, wound healing problems, fracture, overcorrection or chronic regional pain syndrome. There were no cases of further recurrent hallux valgus at followup. Several patients did undergo further lesser toe surgery, all at the phalangeal level. For those with complete data (29 cases) the mean preoperative IMA was 12.98 (range, 6–198), the mean postoperative IMA was 8.98 (range, 2–148), and the mean IMA reduction was 4.08 (range, 3–108, p < 0.001). For those with complete data (29 cases) the mean preoperative HVA was 27.78 (range, 8–408), the mean postoperative HVA was 14.68 (range, 2–298), and the mean HVA reduction was 13.08 (range, 3–328, p < 0.001). The mean AOFAS score preoperatively was 49.6 (range, 14–75), and postoperatively was 83.4 (range, 52–100). The mean increase was 33.8 (range, 5–61, p < 0.001). These results are summarised in Table 2. There was no correlation between change in IMA and AOFAS score (r = 0.13) or improvement in HVA and AOFAS score (r = 0.02). There was a positive trend but no correlation (r = 0.28) between amount of lengthening and AOFAS score change (to signify statistical correlation at p < 0.05 level, r > 0.31). When stratifying patients into smaller or larger length increases, using 4 mm as a cut-off, no correlation was seen. However, when using 5 mm as a cut-off, there was a positive correlation when the lengthening was 6 mm, but no correlation when 5 mm.
B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25 Table 2 Summary of results.
Preoperative Postoperative Improvement Significance
Mean IMA
Mean HVA
Mean AOFAS
12.98 8.98 4.08 p < 0.001
27.78 14.68 13.08 p < 0.001
49.6 83.4 33.8 p < 0.001
The interobserver correlation coefficient for the IMA was 0.95 (95% confidence intervals 0.88–0.98) and for the HVA was 0.90 (0.96–0.99). The intraobserver correlation coefficient was 0.99 (0.99–1.0). There were no significant differences before and after surgery for the SF12 sub-domains of general health, mental health and vitality. Those that showed improvements were physical functioning, physical role functioning, emotional role functioning, social functioning and bodily pain. 4. Discussion The significant improvement in both clinical and radiographical measures suggest that, in our series, lengthening scarf osteotomy for recurrent hallux valgus secondary to iatrogenic first brachymetatarsia is a successful procedure. We hypothesise that restoring both the length and alignment to a short first metatarsal enables greater weight-bearing to take place under the first metatarsal head. This reduces the load transferred laterally under the lesser metatarsal heads and may reduce biomechanical transfer metatarsalgia, as well as addressing medial metatarsal eminence pain. The relationship between first brachymetatarsia and transfer metatarsalgia is well described. Several authors suggest no causative link [15,16], whilst others believe the converse [2–4]. Toth et al. demonstrated a positive correlation between metatarsalgia of the second to fourth rays and first ray shortening [5]. It is uncertain whether the amount of shortening correlates with increased incidence of transfer metatarsalgia, with conflicting reports [2,16–18]. The significant AOFAS score improvement suggests that patients were symptomatically and functionally better after surgery. Only one patient had a reduced AOFAS score (from 57 to 52 as a result of worsening of her pain). All but two improved by a minimum of 15 points. The SF12 results indicate that overall there was no improvement in general health following recovery from surgery, however improvement was seen within physical and pain sub-domains. Mental well-being overall was not affected, although the emotional role functioning sub-domain did improve. Both scoring systems have been validated [19,20], and are widely used although there are some statistical concerns regarding the AOFAS score [21]. The SF-12 inventory has been validated for a variety of differing musculoskeletal conditions, but not specifically in the foot and ankle setting [22]. The radiographic measures indicate good deformity correction, with significant reduction seen in both the IMA and HVA. These angles are well described, easily understood and reproducible. Much is written regarding their reliability. Studies have shown that both inter and intraobserver reliability are excellent, and improved by using digital radiographs and measurements rather than manual techniques [23–25]. We appreciate that there is an element of interobserver variability, especially in the revision setting, where reliable measurements may be more difficult due to anatomical variation following primary osteotomy. However, in our series the inter and intraobserver reliability was excellent. We used standardised weight-bearing
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radiographs at all times to minimise this error and accurately assess the deformity. Use of the scarf osteotomy as a revision procedure for recurrent hallux valgus is well described. Bock et al. performed a retrospective study analysing a 60 patient cohort who underwent scarf osteotomy following failed primary hallux valgus surgery resulting in painful recurrence [12]. They reported excellent clinical and radiographic results for 39 feet. Importantly, however, the study excluded 19 patients for reasons including a large deformity or the presence of transfer metatarsalgia, and made no mention of lengthening. Use of the lengthening scarf osteotomy has been previously described. Singh and Dudkiewicz [9] described a prospective cohort series of scarf osteotomies for metatarsalgia as a result of iatrogenic first brachymetatarsia. This was a relatively small series (16 patients), although such a procedure for this indication had only been previously described once [26]. All had previously undergone a Wilson osteotomy (unlike our series, where the primary procedure was variable), were complaining of transfer metatarsalgia and had callosities under the second metatarsal head. In each case a 10 mm bone graft block was interposed at the distraction site. In five cases the extensor hallucis longus tendon was lengthened, and in two of these the proximal phalanx was shortened to prevent first MTPJ stiffness. The authors reported good results with first metatarsal lengthening of at least 8 mm, with no stiffness identified. Relief of metatarsalgia symptoms was inadequate in those lengthened less than 8 mm. The osteotomy cut angles were altered after the first four cases, improving results, but adding a layer of data heterogeneity. Furthermore, the analysis was not particularly robust, utilising crude radiographic and clinical signs, with no formal validated scoring systems employed, and no statistical analysis performed. In our series we assessed for stiffness intra-operatively ensuring the lengthening amount was not over-ambitious to the extent that it might result in MTPJ stiffness. Although preoperatively we selected our maximum lengthening as 10 mm in order to prevent any potential stiffness, identical to Singh [9], we achieved a maximum of 8 mm. This approach, combined with patients being instructed on mobilising the first MTPJ early, resulted in no stiffness identified in our series. Singh suggested that lengthening less than 8 mm is inadequate. We identified a positive trend but no correlation between amount of lengthening and change in AOFAS score but were unable to prove statistical significance for this, or when stratifying patients into larger or smaller amounts of lengthening. Unlike previous reports, we did not use interposition bone graft, and experienced no problems maintaining the lengthening or with the development of non-union. Iatrogenic first brachymetatarsia may be treated using alternative techniques, including distraction osteogenesis, one-stage lengthening using bone graft or shortening of adjacent metatarsals. These have mostly been developed to treat congenital brachymetatarsia. One-stage lengthening enables a shorter recovery period than distraction osteogenesis, but may produce donor site morbidity, tendons may become tethered and only a small length gain may be possible if there is neurovascular compromise [27,28]. A maximum of 15 mm lengthening is recommended [27]. It may be used with adjacent metatarsal shortening, using the excised bone as graft for the first metatarsal [29]. The use of distraction osteogenesis has been well described, mostly for congenital deformities, with good results [28,30–34]. There has been one small study successfully demonstrating its use for iatrogenic first brachymetatarsia without complications [31]. It does not require bone grafting, enables tissue stretching over a longer time period and potentially enables a greater length gain.
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B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25
Potential disadvantages include pin site infection, scarring, MTPJ stiffness, cavus or angulation deformity and longer recovery time [27,28,30,32]. Stiffness may be avoided if the gain in length is less than 40% of the original metatarsal length [27]. In our series the hallux valgus deformity added an extra plane in which correction was required compared to congenital brachymetatarsia. It may not be legitimate therefore to compare the above procedures for recurrent hallux valgus correction. The complication levels may be increased, especially within distraction osteogenesis, where development of hallux valgus deformity itself is a recognised complication [30]. Isolated metatarsalgia has traditionally been treated surgically by Weil osteotomy. For this indication, good results are well described [35–37]. The most common complications are MTPJ stiffness, floating toe, ongoing pain (due to insufficient shortening) and further transfer metatarsalgia laterally (due to excessive shortening) [35,37,38]. None of these studies refer to recurrent hallux valgus, and none with first brachymetatarsia. If this is the underlying cause of patients’ symptomatic transfer metatarsalgia, it is possible to shorten the remaining four rays, thereby paradoxically lengthening the first ray. This would not address the hallux valgus deformity, which would still require an osteotomy. There is no evidence for this in the recurrent hallux valgus setting. Furthermore, in addition to the previously described complications, the forefoot will shorten, further altering the anatomy. In our study, the cohort additionally undergoing Weil osteotomies did not differ in any significant fashion from those simply undergoing a lengthening scarf osteotomy either in preoperative or postoperative findings. We therefore believe that this can be excluded as a confounding factor from the results we have seen and the conclusions we draw. Our study does have several limitations. The series is from a single surgeon (AS) with no randomisation, control group or blinding. Interpretation of radiographs, and acquisition of scores inevitably adds a layer of subjectivity, although these have been validated, and we have demonstrated excellent inter and intraobserver reliability. The index hallux valgus procedure within the cohort was highly variable, but the number of cases did not allow for further stratification. The initial procedure may have affected the anatomy and foot biomechanics differently. Lengthening the first metatarsal can increase the joint reaction force at the first MTPJ, which may pre-dispose to early degenerative change. Longer followup may reveal this, or an as-yet unseen recurrence rate. Larger numbers and improved followup may enable the results to achieve greater statistical significance, preventing a type two error. 5. Conclusion We have described the largest series of lengthening scarf osteotomy for recurrent hallux valgus with medial metatarsal eminence pain and iatrogenic first brachymetatarsia. Our results suggest the procedure is successful, with a low complication rate. Lengthening did not reduce the range of movement. We anticipate that restoring both the length and alignment to a short first metatarsal improves medial metatarsal eminence pain and enables greater weight-bearing to take place under the first metatarsal thus reducing transfer metatarsalgia over time. Conflict of interest statement The authors have had no conflict of interests in the preparation of this work. The authors have not directly or indirectly benefited financially, or otherwise, in the preparation of this work.
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Contents lists available at ScienceDirect
Foot and Ankle Surgery journal homepage: www.elsevier.com/locate/fas
Lengthening scarf osteotomy for recurrent hallux valgus Barry Rose MA, FRCS (Eng)*, Nicholas Bowman FRCS (Tr & Orth), Huw Edwards MB, BS, BSc, Samuel S. Rajaratnam FRCS (Tr & Orth), Andrew R. Armitage FRCS (Tr & Orth), Andrew D. Skyrme FRCS (Tr & Orth) Eastbourne District General Hospital, East Sussex, UK
A R T I C L E I N F O
A B S T R A C T
Article history: Received 26 June 2013 Received in revised form 6 August 2013 Accepted 22 August 2013
Background: We describe using the scarf osteotomy to correct a recurrent hallux valgus deformity and lengthen the shortened first metatarsal in symptomatic iatrogenic first brachymetatarsia. Methods: Thirty-six lengthening scarf osteotomies were undertaken in 31 patients. Clinical and radiographic measures were taken pre and postoperatively. Results: Mean age at presentation was 53.4 years, and mean followup 3.9 years. The mean lengthening achieved was 4.9 mm. All osteotomies united with no complications. The mean IMA reduction was 4.08 (p < 0.001) and HVA 13.08 (p < 0.001). The mean AOFAS score increase was 33.8 (p < 0.001). There was a positive trend but no correlation (r = 0.28) between amount of metatarsal lengthening and AOFAS score change. Conclusions: We describe the largest lengthening scarf osteotomy series for recurrent hallux valgus with iatrogenic first brachymetatarsia. The results suggest the procedure is successful, with a low complication rate. We anticipate that restoring first metatarsal length and alignment may reduce biomechanical transfer metatarsalgia over time. ß 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Hallux valgus Metatarsalgia Osteotomy Bone lengthening
1. Introduction A myriad of procedures have been described to surgically correct hallux valgus. There is a variable but significant recurrence risk following such surgery. Patients may present with a recurrence of their deformity, pain at the medial metatarsal eminence or transfer metatarsalgia [1]. Such symptoms may be the result of an iatrogenic first brachymetatarsia following the index surgical procedure. Shortening of the first metatarsal has been shown to correlate with the onset of transfer metatarsalgia [2–5], although many other causes of forefoot pain do exist. The scarf osteotomy has been popularised by Barouk in recent years as a technique for primary hallux valgus surgery [6]. This zstep carpentry term was originally described as a metatarsal osteotomy by Meyer in 1926 [7], but not widely used. It was redescribed in 1976 by Burutaran [8]. The z-step osteotomy is potentially a powerful surgical tool, allowing for correction of moderate to severe deformities. By altering the configuration of the bone cuts one can translate the metatarsal head in both the mediallateral (sagittal) as well as the plantar-dorsal (coronal) planes.
Furthermore, the osteotomy may enable rotation, to correct an increased distal metatarsal articulation angle (DMAA), and can facilitate shortening or lengthening of the metatarsal. It can therefore be used to address the first brachymetatarsia seen in some patients presenting with recurrent symptomatic hallux valgus or transfer metatarsalgia as a result of an iatrogenic shortened first ray [9]. Singh and Dudkiewicz [9] describe a prospective cohort series of 16 patients undergoing scarf osteotomy for metatarsalgia as a result of iatrogenic first brachymetatarsia following a Wilson’s osteotomy. The authors report good results with first metatarsal lengthening of at least 8 mm. Other evidence within the literature for the employment of the scarf osteotomy for this use is scanty. The purpose of this study therefore was to further assess the results of a lengthening scarf osteotomy in a prospective cohort of patients with symptomatic hallux valgus recurrence and iatrogenic first brachymetatarsia. We anticipate that restoring the length and alignment may reduce medial metatarsal eminence pain and lesser ray pain as a result of biomechanical transfer metatarsalgia over time. 2. Methods
* Corresponding author at: 18 Mereworth Road, Tunbridge Wells, Kent TN4 9PL, UK. Tel.: +44 7779620019. E-mail address: [email protected] (B. Rose).
A prospective cohort of patients was recruited from specialist foot and ankle clinics run by the senior author in three institutions
1268-7731/$ – see front matter ß 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fas.2013.08.004
B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25
between 2006 and 2010. All patients underwent clinical and radiographic assessment. All patients who had undergone previous hallux valgus bony surgery were considered. The nature of the surgery did not preclude inclusion. Patients were considered eligible for lengthening scarf osteotomy if they presented with recurrent hallux valgus and medial metatarsal eminence pain. They also required radiographic evidence of iatrogenic first brachymetatarsia (significant first metatarsal shortening from normal, judged using the ipsilateral lesser metatarsal arcade as a reference for the native first metatarsal length) (Fig. 1). Radiographs from prior to the index procedure were unavailable. The presence of transfer metatarsalgia (defined as pain felt under the lesser metatarsal heads, with or without associated plantar callosities) was noted from the history and examination. This was investigated as indicated by blood testing and further imaging to exclude other causes of pain including inflammatory arthropathy and interdigital neuromas. Excluded patients included: those skeletally immature individuals, those medically unfit for surgery and those with concurrent midfoot or hindfoot pathology, or previous midfoot or hindfoot surgery. A minimum of 12 months followup was necessary for inclusion. All patients were seen and assessed by the senior author (AS) preoperatively. Their symptoms were evaluated clinically using the American Orthopaedic Foot and Ankle Society (AOFOS) score [10] and the Short Form 12 (SF12) inventory [11]. Radiographic assessment of weight-bearing views measured the Hallux Valgus Angle (HVA) and Intermetatarsal Angle (IMA), standard measures of the severity and nature of hallux valgus (Fig. 2) [12]. All radiographs were made available from the hospital Patient Archiving Communication System (PACS). Angles were measured using the in-built PACS tools, and rounded to the nearest whole number. These measurements were performed for all radiographs by two independent observers (BR and NB), and repeated after an interval of two weeks, enabling the calculation of Pearson’s product moment correlation coefficient to assess inter and intraobserver reliability.
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Hospital-approved written clinical information leaflets were available to patients explaining the nature of surgery, including the postoperative course. All patients gave written informed consent for surgery. In all cases the senior author performed a scarf osteotomy with lateral translation and/or rotation of the distal fragment as part of the standard procedure. The osteotomy incorporated first metatarsal lengthening to re-establish the bone length by angling the z-step cuts distally, facilitating a gain in length when rotation and/or translation occurred. The length gain was predicted radiographically preoperatively and determined intra-operatively by the appearance and soft-tissue tension. The maximum planned lengthening was 10 mm. The actual gain in length was measured intra-operatively with callipers and a ruler. No attempt was made to plantarflex the first ray, which can theoretically be used to achieve a similar effect to lengthening the metatarsal. The remainder of the procedure followed the standard principles of hallux valgus surgery, including a complete lateral soft tissue release in all cases to ensure correct soft tissue tension and prevent postoperative stiffness at the metatarsophalangeal joint (MTPJ). The range of motion at the MTPJ was assessed prior to closure to ensure no inherent stiffness. Lesser metatarsal Weil osteotomies were undertaken as necessary solely to restore the arcade of the metatarsal heads, but not with the aim of achieving paradoxical first metatarsal lengthening. Symptomatic preoperative transfer metatarsalgia in itself was not an indication to perform Weil osteotomies. Any lesser toe procedures were undertaken concurrently. Postoperatively, patients were seen in our clinic as per standard postoperative protocol. Once full recovery had occurred, clinical assessment was undertaken with the AOFAS score and SF12 inventory re-performed, and the same radiographic measures repeated. Data was analysed using IBM SPSS Statistics Version 19 (IBM Corporation, Armonk, New York, USA). Categorical data were expressed as a number and continuous data as a mean. The differences between pre and postoperative radiographic results and AOFAS scores were assessed using paired sample t-tests. Pearson’s product moment correlation coefficient was calculated
Fig. 1. Example of pre and post-operative radiographs.
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B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25
Fig. 2. Example of pre and post-operative radiographs annotated to calculate IMA and HVA.
to determine the relationship between the amount of lengthening and the change in objective and subjective parameters. A p value of less than 0.05 was considered statistically significant. This study was performed within the confines of the Research Governance Framework and the 2008 Declaration of Helsinki [13,14]. 3. Results Thirty-one patients (28 female, three male) were identified and included in the cohort. Thirty-six lengthening scarf osteotomies were undertaken. No patient underwent simultaneous bilateral procedures. The mean age at presentation was 53.4 (range, 26–76) years. In all 36 cases, patients described recurrence of hallux valgus with pain at the medial metatarsal eminence, and in 20 cases, transfer metatarsalgia was also described. The mean time of revision surgery from the index surgical procedure was 10.0 (range, 1–31) years. The index procedures are summarised in Table 1. The mean followup was 3.9 (range, 1–5) years. Radiographic data was incomplete in seven cases (19%): two without preoperative imaging and five without postoperative imaging available. In four cases (11%) the AOFAS score was incomplete and in five cases (14%) the SF12 inventory was not completed, despite a minimum of three attempts to contact the individuals. This data was excluded from analysis.
Table 1 Breakdown of index procedure. Index surgical procedure
Number (percentage)
Wilson osteotomy Bunionectomy Chevron osteotomy Mitchell osteotomy Scarf osteotomy Unknown
17 11 3 3 1 1
(47%) (31%) (8%) (8%) (3%) (3%)
The mean first metatarsal lengthening achieved was 4.9 (range, 1–8) mm. There were 27 Akin osteotomies, and 24 lesser toe procedures, including Weil osteotomies in 16 cases. There was no significant difference (p = 0.07) between the length gained in the group undergoing concurrent Weil osteotomies (mean 5.4 mm), and the group without a lesser metatarsal osteotomy (mean 4.4 mm). There were no other pre or postoperative distinguishing features between these two groups, either clinical or radiographic. All osteotomies united clinically and radiographically. In no cases was there a loss of first MTPJ range of movement. There were no cases of infection, wound healing problems, fracture, overcorrection or chronic regional pain syndrome. There were no cases of further recurrent hallux valgus at followup. Several patients did undergo further lesser toe surgery, all at the phalangeal level. For those with complete data (29 cases) the mean preoperative IMA was 12.98 (range, 6–198), the mean postoperative IMA was 8.98 (range, 2–148), and the mean IMA reduction was 4.08 (range, 3–108, p < 0.001). For those with complete data (29 cases) the mean preoperative HVA was 27.78 (range, 8–408), the mean postoperative HVA was 14.68 (range, 2–298), and the mean HVA reduction was 13.08 (range, 3–328, p < 0.001). The mean AOFAS score preoperatively was 49.6 (range, 14–75), and postoperatively was 83.4 (range, 52–100). The mean increase was 33.8 (range, 5–61, p < 0.001). These results are summarised in Table 2. There was no correlation between change in IMA and AOFAS score (r = 0.13) or improvement in HVA and AOFAS score (r = 0.02). There was a positive trend but no correlation (r = 0.28) between amount of lengthening and AOFAS score change (to signify statistical correlation at p < 0.05 level, r > 0.31). When stratifying patients into smaller or larger length increases, using 4 mm as a cut-off, no correlation was seen. However, when using 5 mm as a cut-off, there was a positive correlation when the lengthening was 6 mm, but no correlation when 5 mm.
B. Rose et al. / Foot and Ankle Surgery 20 (2014) 20–25 Table 2 Summary of results.
Preoperative Postoperative Improvement Significance
Mean IMA
Mean HVA
Mean AOFAS
12.98 8.98 4.08 p < 0.001
27.78 14.68 13.08 p < 0.001
49.6 83.4 33.8 p < 0.001
The interobserver correlation coefficient for the IMA was 0.95 (95% confidence intervals 0.88–0.98) and for the HVA was 0.90 (0.96–0.99). The intraobserver correlation coefficient was 0.99 (0.99–1.0). There were no significant differences before and after surgery for the SF12 sub-domains of general health, mental health and vitality. Those that showed improvements were physical functioning, physical role functioning, emotional role functioning, social functioning and bodily pain. 4. Discussion The significant improvement in both clinical and radiographical measures suggest that, in our series, lengthening scarf osteotomy for recurrent hallux valgus secondary to iatrogenic first brachymetatarsia is a successful procedure. We hypothesise that restoring both the length and alignment to a short first metatarsal enables greater weight-bearing to take place under the first metatarsal head. This reduces the load transferred laterally under the lesser metatarsal heads and may reduce biomechanical transfer metatarsalgia, as well as addressing medial metatarsal eminence pain. The relationship between first brachymetatarsia and transfer metatarsalgia is well described. Several authors suggest no causative link [15,16], whilst others believe the converse [2–4]. Toth et al. demonstrated a positive correlation between metatarsalgia of the second to fourth rays and first ray shortening [5]. It is uncertain whether the amount of shortening correlates with increased incidence of transfer metatarsalgia, with conflicting reports [2,16–18]. The significant AOFAS score improvement suggests that patients were symptomatically and functionally better after surgery. Only one patient had a reduced AOFAS score (from 57 to 52 as a result of worsening of her pain). All but two improved by a minimum of 15 points. The SF12 results indicate that overall there was no improvement in general health following recovery from surgery, however improvement was seen within physical and pain sub-domains. Mental well-being overall was not affected, although the emotional role functioning sub-domain did improve. Both scoring systems have been validated [19,20], and are widely used although there are some statistical concerns regarding the AOFAS score [21]. The SF-12 inventory has been validated for a variety of differing musculoskeletal conditions, but not specifically in the foot and ankle setting [22]. The radiographic measures indicate good deformity correction, with significant reduction seen in both the IMA and HVA. These angles are well described, easily understood and reproducible. Much is written regarding their reliability. Studies have shown that both inter and intraobserver reliability are excellent, and improved by using digital radiographs and measurements rather than manual techniques [23–25]. We appreciate that there is an element of interobserver variability, especially in the revision setting, where reliable measurements may be more difficult due to anatomical variation following primary osteotomy. However, in our series the inter and intraobserver reliability was excellent. We used standardised weight-bearing
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radiographs at all times to minimise this error and accurately assess the deformity. Use of the scarf osteotomy as a revision procedure for recurrent hallux valgus is well described. Bock et al. performed a retrospective study analysing a 60 patient cohort who underwent scarf osteotomy following failed primary hallux valgus surgery resulting in painful recurrence [12]. They reported excellent clinical and radiographic results for 39 feet. Importantly, however, the study excluded 19 patients for reasons including a large deformity or the presence of transfer metatarsalgia, and made no mention of lengthening. Use of the lengthening scarf osteotomy has been previously described. Singh and Dudkiewicz [9] described a prospective cohort series of scarf osteotomies for metatarsalgia as a result of iatrogenic first brachymetatarsia. This was a relatively small series (16 patients), although such a procedure for this indication had only been previously described once [26]. All had previously undergone a Wilson osteotomy (unlike our series, where the primary procedure was variable), were complaining of transfer metatarsalgia and had callosities under the second metatarsal head. In each case a 10 mm bone graft block was interposed at the distraction site. In five cases the extensor hallucis longus tendon was lengthened, and in two of these the proximal phalanx was shortened to prevent first MTPJ stiffness. The authors reported good results with first metatarsal lengthening of at least 8 mm, with no stiffness identified. Relief of metatarsalgia symptoms was inadequate in those lengthened less than 8 mm. The osteotomy cut angles were altered after the first four cases, improving results, but adding a layer of data heterogeneity. Furthermore, the analysis was not particularly robust, utilising crude radiographic and clinical signs, with no formal validated scoring systems employed, and no statistical analysis performed. In our series we assessed for stiffness intra-operatively ensuring the lengthening amount was not over-ambitious to the extent that it might result in MTPJ stiffness. Although preoperatively we selected our maximum lengthening as 10 mm in order to prevent any potential stiffness, identical to Singh [9], we achieved a maximum of 8 mm. This approach, combined with patients being instructed on mobilising the first MTPJ early, resulted in no stiffness identified in our series. Singh suggested that lengthening less than 8 mm is inadequate. We identified a positive trend but no correlation between amount of lengthening and change in AOFAS score but were unable to prove statistical significance for this, or when stratifying patients into larger or smaller amounts of lengthening. Unlike previous reports, we did not use interposition bone graft, and experienced no problems maintaining the lengthening or with the development of non-union. Iatrogenic first brachymetatarsia may be treated using alternative techniques, including distraction osteogenesis, one-stage lengthening using bone graft or shortening of adjacent metatarsals. These have mostly been developed to treat congenital brachymetatarsia. One-stage lengthening enables a shorter recovery period than distraction osteogenesis, but may produce donor site morbidity, tendons may become tethered and only a small length gain may be possible if there is neurovascular compromise [27,28]. A maximum of 15 mm lengthening is recommended [27]. It may be used with adjacent metatarsal shortening, using the excised bone as graft for the first metatarsal [29]. The use of distraction osteogenesis has been well described, mostly for congenital deformities, with good results [28,30–34]. There has been one small study successfully demonstrating its use for iatrogenic first brachymetatarsia without complications [31]. It does not require bone grafting, enables tissue stretching over a longer time period and potentially enables a greater length gain.
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Potential disadvantages include pin site infection, scarring, MTPJ stiffness, cavus or angulation deformity and longer recovery time [27,28,30,32]. Stiffness may be avoided if the gain in length is less than 40% of the original metatarsal length [27]. In our series the hallux valgus deformity added an extra plane in which correction was required compared to congenital brachymetatarsia. It may not be legitimate therefore to compare the above procedures for recurrent hallux valgus correction. The complication levels may be increased, especially within distraction osteogenesis, where development of hallux valgus deformity itself is a recognised complication [30]. Isolated metatarsalgia has traditionally been treated surgically by Weil osteotomy. For this indication, good results are well described [35–37]. The most common complications are MTPJ stiffness, floating toe, ongoing pain (due to insufficient shortening) and further transfer metatarsalgia laterally (due to excessive shortening) [35,37,38]. None of these studies refer to recurrent hallux valgus, and none with first brachymetatarsia. If this is the underlying cause of patients’ symptomatic transfer metatarsalgia, it is possible to shorten the remaining four rays, thereby paradoxically lengthening the first ray. This would not address the hallux valgus deformity, which would still require an osteotomy. There is no evidence for this in the recurrent hallux valgus setting. Furthermore, in addition to the previously described complications, the forefoot will shorten, further altering the anatomy. In our study, the cohort additionally undergoing Weil osteotomies did not differ in any significant fashion from those simply undergoing a lengthening scarf osteotomy either in preoperative or postoperative findings. We therefore believe that this can be excluded as a confounding factor from the results we have seen and the conclusions we draw. Our study does have several limitations. The series is from a single surgeon (AS) with no randomisation, control group or blinding. Interpretation of radiographs, and acquisition of scores inevitably adds a layer of subjectivity, although these have been validated, and we have demonstrated excellent inter and intraobserver reliability. The index hallux valgus procedure within the cohort was highly variable, but the number of cases did not allow for further stratification. The initial procedure may have affected the anatomy and foot biomechanics differently. Lengthening the first metatarsal can increase the joint reaction force at the first MTPJ, which may pre-dispose to early degenerative change. Longer followup may reveal this, or an as-yet unseen recurrence rate. Larger numbers and improved followup may enable the results to achieve greater statistical significance, preventing a type two error. 5. Conclusion We have described the largest series of lengthening scarf osteotomy for recurrent hallux valgus with medial metatarsal eminence pain and iatrogenic first brachymetatarsia. Our results suggest the procedure is successful, with a low complication rate. Lengthening did not reduce the range of movement. We anticipate that restoring both the length and alignment to a short first metatarsal improves medial metatarsal eminence pain and enables greater weight-bearing to take place under the first metatarsal thus reducing transfer metatarsalgia over time. Conflict of interest statement The authors have had no conflict of interests in the preparation of this work. The authors have not directly or indirectly benefited financially, or otherwise, in the preparation of this work.
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