Proximal metatarsal osteotomies: a comparative geometric analysis conducted on sawbone models

We evaluated the change in position of the first metatarsal head using a three-dimensional digitizer on sawbone models. Crescentic, closing wedge, oblique shaft (Ludloff 8 degrees and 16 degrees), reverse oblique shaft (Mau 8 degrees and 16 degrees), rotational "Z" (Scarf), and proximal chevron osteotomies were performed and secured using 3-mm screws. The 16 degrees Ludloff provided the most lateral shift (9.5 mm) and angular correction (14.5 degrees) but also produced the most elevation (1.4 mm) and shortening (2.9 mm). The 8 degrees Ludloff provided lateral and angular corrections similar to those of the crescentic and closing wedge osteotomies with less elevation and shortening. Because the displacement osteotomies (Scarf, proximal chevron) provided less angular correction, the same lateral displacement, and less shortening than the basilar angular osteotomies, based upon this model they can be more reliably used for a patient with a mild to moderate deformity, a short first metatarsal, or an intermediate deformity with a large distal metatarsal articular angle. These results can serve as recommendations for selecting the optimal osteotomy with which to correct a deformation.     

Mechanical comparison of cyclic loading in five different first metatarsal shaft osteotomies

The purposes of the current study were: 1. to analyze the relative fatigue endurance of five different first metatarsal shaft osteotomies (proximal crescentic, proximal chevron, Ludloff, Mau, and Scarf), as performed on sawbone models using the most common fixation techniques (part I); and 2. to compare the two more commonly used techniques (per part I results) in matched-pair cadaver specimens (part II). In part I, the proximal chevron and Mau osteotomies were significantly more stable (P < or = 0.005) than all other osteotomies except the Ludloff. In part II, there was no significant difference in fatigue endurance between the proximal chevron and Ludloff osteotomies.     

Strength of fixation of Ludloff metatarsal osteotomy utilizing three different types of Kirschner wires: a biomechanical study

Static biomechanical studies have demonstrated that the Ludloff shaft metatarsal osteotomy is significantly more stable than other commonly used proximal (basilar) osteotomies, such as the proximal crescentic and the proximal chevron. High average static bending failure moments have been recorded for the screw fixation Ludloff osteotomy construct. The objective of the current study was to find a reasonable alternative method of fixation in cases where a short osteotomy may not be amenable to adequate screw fixation and in cases where an inadvertent intraoperative fracture of the metatarsal occurs and subsequent screw fixation is precarious due to inadequate bone stock. A Ludloff osteotomy was performed on 24 matched pairs of cadaveric specimens to compare the strength of fixation of three different types of Kirschner wires (smooth, threaded, and SOC threaded). Biomechanical testing with plantar force was carried out, and failure load and stiffness were measured for each specimen. The current results indicate that the threaded pin construct provides adequate strength for fixation of the Ludloff osteotomy in the clinical setting.     

Angular correction and complications of proximal first metatarsal osteotomies for hallux valgus deformity

Purpose

Proximal first metatarsal osteotomies are recommended for the surgical treatment of moderate to severe hallux valgus deformity. This study aimed to compare correction of intermetatarsal and hallux valgus angles and complications of proximal crescentic, Ludloff, proximal opening wedge, proximal closing wedge, proximal chevron and other proximal first metatarsal osteotomies.

Methods

A systematic search for the keywords “(bunion OR hallux) AND (proximal OR crescentic OR basilar OR opening OR closing OR shelf OR Ludloff) AND osteotomy” in the online databases MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews was performed.

Results

There was a mean correction of hallux valgus angle of 20.1° [confidence interval (CI) 18.7–21.4] and of intermetatarsal angle of 8.1° (CI 7.7–8.9). The overall complication rate reached 18.7 %.

Conclusions

The results of this study reveal higher corrective power of proximal osteotomies compared to meta-analysis data on diaphyseal osteotomies.     

Supplementary axial Kirschner wire fixation for crescentic and Ludloff proximal metatarsal osteotomies: a biomechanical study

BACKGROUND: Loss of reduction of proximal metatarsal osteotomies may result from poor bone quality, suboptimal fixation, and limitations inherent in the bony geometry of the osteotomy. This study evaluated the mechanical benefit of adding two supplementary Kirschner wires to the crescentic and Ludloff osteotomies. METHODS: Eleven and 10 matched pairs of cadaver foot specimens were used for the Ludloff and the proximal crescentic metatarsal osteotomies, respectively. Each metatarsal head specimen was then loaded to failure using a servohydraulic MTS Mini Bionix test frame (MTS Systems Corp, Eden Prairie, MN), and the failure gap was measured with an extensometer. To account for variable bone quality in the study specimens, the failure loads were normalized with the measured bone mineral density (BMD) values of the metatarsal specimens. A paired Student's t-test analysis was used to compare the failure loads between the specimens with the conventional osteotomies and the osteotomies supplemented with two axial Kirschner wires. RESULTS: The load-to-failure of the Ludloff osteotomy with two screws and with one proximal screw and two Kirschner wires was 858.5 N cm(2)/gm and 692.3 N cm(2)/gm, respectively (p > 0.05). The average load-to-failure of crescentic osteotomy with one screw and two axial Kirschner wires (458.8 N cm(2)/gm) was significantly higher than the strength of crescentic osteotomy fixed with one screw only (367.5 N cm(2)/gm) (p = 0.05). For the Ludloff osteotomy, 16 specimens (72.7%) failed by more than 2 mm of gapping. The crescentic osteotomy failures included 16 2-mm gap failures (80%). The Ludloff osteotomy showed a trend toward increased fixation stability as compared with both crescentic osteotomy constructs. CONCLUSION: The use of two supplemental axial Kirschner wires offers a simple and effective means to improve the initial mechanical stability of the proximal crescentic osteotomy and can be used in the standard Ludloff osteotomy to replace the second screw when screw purchase is poor without significant loss of fixation strength. The possible advantage of Kirschner wire flexibility in restoring position after gapping of the osteotomy site should be investigated.     

Clinical results with the Ludloff osteotomy for correction of adult hallux valgus

BACKGROUND: Biomechanically, the Ludloff osteotomy fixed with lag screw compression has been shown to be more rigid than proximal crescentic and other proximal first metatarsal osteotomies for correction of symptomatic hallux valgus with a moderate to severe increase in the first intermetatarsal angle. The Ludloff osteotomy may, therefore, have a lower incidence of dorsal malunion and transfer metatarsalgia than other proximal first metatarsal osteotomies, such as the crescentic or chevron. METHODS: We reviewed the results of 82 consecutive cases of moderate to severe hallux valgus deformities corrected with the Ludloff oblique metaphyseal-diaphyseal osteotomy of the first metatarsal combined with a distal soft-tissue procedure and medial eminence resection. RESULTS: Follow-up was possible in 70 cases (85%) at an average of 30 months (range, 18 to 42 months). Preoperatively, the mean hallux valgus and first intermetatarsal angles were 31 degrees and 16 degrees, respectively. Postoperatively, these values improved to an average of 11 degrees and 7 degrees. In the sagittal plane, the first metatarsal was plantarflexed by an average of 1 mm, and there were no symptomatic transfer lesions of the second metatarsal. The mean AOFAS hindfoot score improved from 54 to 91 points. Complications included prominent hardware requiring removal (5), hallux varus (4), delayed union (3), superficial infection (3), and neuralgia (3). CONCLUSIONS: The use of the Ludloff oblique first metatarsal osteotomy resulted in excellent correction of the first intermetatarsal angle in patients with moderate to severe hallux valgus. With the plane of the osteotomy and rigidity of fixation, immediate ambulation was possible with minimal risk of dorsiflexion malunion of the first metatarsal.     

Fixation of metatarsal osteotomies in the treatment of hallux valgus

Osteotomies as a treatment for hallux valgus require careful preoperative planning and meticulous attention to surgical technique. The procedure selected should be tailored to fit the deformity. For a patient with mild hallux valgus, the chevron osteotomy is the most intrinsically stable of the distal osteotomies and has the least potential for complications. Interest in the Ludloff osteotomy has had a resurgence because of its improved stability compared with more traditional osteotomies for correction of metatarsus primus varus. This osteotomy, however, is less forgiving and more dependent on technique than other procedures. The proximal chevron osteotomy, with plantar-to-dorsal screw placement, is easier to perform than the Ludloff and provides excellent stability. Regardless of the osteotomy used, screw fixation has been shown to be mechanically superior to all other modes of fixation (K-wire, staples, or no fixation). Postoperatively, a hard-soled postoperative shoe that permits weight-bearing on the heel and lateral foot is recommended; however, for the more unstable osteotomies and for those performed in patients with poor bone quality, a period of non-weight-bearing should be considered. Future studies with cyclic loading may help modify these current postoperative restrictions.     

Relative Strength of Tailor’s Bunion Osteotomies and Fixation Techniques

A paucity of data is available on the mechanical strength of fifth metatarsal osteotomies. The present study was designed to provide that information. Five osteotomies were mechanically tested to failure using a materials testing machine and compared with an intact fifth metatarsal using a hollow saw bone model with a sample size of 10 for each construct. The osteotomies tested were the distal reverse chevron fixated with a Kirschner wire, the long plantar reverse chevron osteotomy fixated with 2 screws, a mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, the mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, and an additional cerclage wire and a transverse closing wedge osteotomy fixated with a box wire technique. Analysis of variance was performed, resulting in a statistically significant difference among the data at p <.0001. The Tukey-Kramer honestly significant difference with least significant differences was performed post hoc to separate out the pairs at a minimum α of 0.05. The chevron was statistically the strongest construct at 130 N, followed by the long plantar osteotomy at 78 N. The chevron compared well with the control at 114 N, and they both fractured at the proximal model to fixture interface. The other osteotomies were statistically and significantly weaker than both the chevron and the long plantar constructs, with no statistically significant difference among them at 36, 39, and 48 N. In conclusion, the chevron osteotomy was superior in strength to the sagittal and transverse plane osteotomies and similar in strength and failure to the intact model.     

Osteotomies of the fifth metatarsal.

Although the literature is limited primarily to retrospective small case series of the operative technique of fifth metatarsal osteotomies with a short follow-up, some important information can be learned. Stabilization of the osteotomy with Kirschner wire fixation appears to decrease dorsal displacement of the distal fragment and distal osteotomies; this leads to decreased incidence of transfer metatarsalgia. Kirschner wire fixation is advocated. The proximal chevron osteotomy of the fifth metatarsal, although stable, has a 20% delayed union rate, most likely resulting from the unique vascular anatomy in this region. The radiographic and clinical results appear to be compatible between distal and proximal osteotomies. Based on this information, primary use of a proximal osteotomy technique is not recommended. The oblique diaphyseal osteotomy technique requires an incision for the osteotomy as well as a distal incision at the metatarsophalangeal joint for correction of this joint. Hardware removal was performed in most patients, and the complications included two cases of delayed union. Time to healing was reported to be 8 weeks, 1.5 times the reported time to healing in distal chevron osteotomies. A significant radiographic correction was noted with the oblique diaphyseal osteotomy; however, radiographic measurements can be altered with foot position and lack of x-ray standardization and technique. Kitaoka et al found no correlation with the degree of radiographic correction and post-operative clinical symptoms. The authors agree with Kitaoka et al that the oblique diaphyseal osteotomy should be reserved for patients who fail an initial distal osteotomy technique. Distal oblique osteotomies appear to have less stability and more complications with malunion, transfer metatarsalgia, and delayed union and should be abandoned for a more stable chevron technique. The distal chevron osteotomy has a small incidence of transfer metatarsalgia; however, it appears to improve the clinical radiographic appearance of [table: see text] the foot with a shortened time to healing (4 to 6 weeks). A biplanar technique can be employed with a distal chevron osteotomy to improve plantar callosity symptoms. More studies are needed to examine critically patient outcomes with uniplanar and biplanar techniques using the distal chevron osteotomy.     

The effect of screw type on the biomechanical properties of SCARF and crescentic osteotomies of the first metatarsal

The basilar crescentic osteotomy is a popular method for correcting moderate to severe hallux valgus. However, inadvertent dorsiflexion of the osteotomy can result from intraoperative malposition or from malunion after fixation failure. The mechanical properties of osteotomies are dependent on the nature of the osteotomy and the type of fixation. This study examines the mechanical properties of the SCARF and crescentic osteotomies of the first metatarsal by using a cannulated asymmetric pitched screw or AO cancellous screws. Sixteen human cadaveric first metatarsal specimens were tested in plantar to dorsiflexion cantilever bending by using a mechanical testing machine. The data was compared with our recent work on the mechanical properties of the SCARF and crescentic osteotomies. Ultimate load and stiffness of the SCARF osteotomy were superior to the crescentic osteotomy but were not dependent on screw type. Screw type was a prominent factor in the stiffness but not in the strength of the crescentic osteotomy. The ultimate load and the stiffness of SCARF osteotomy fixed with the cannulated asymmetric pitched screws were not significantly different compared with AO screws (ultimate load, 124.6 N [SD = 56.8] v 105.3 N [SD = 57.0]; stiffness, 52.0 N/mm [SD = 48.0] v 31.8 N/mm [SD = 19.0]). Modes of failure were fracture of the cortical bone bridge between the screw hole and the osteotomy in all crescentic osteotomies and fracture of the proximal dorsal bridge in all SCARF osteotomies. The superior mechanical properties of the SCARF osteotomy, fixed with cannulated asymmetric pitched screws, make this a more secure construct, with less risk of malunion than the crescentic osteotomy. Stiffness is an important mechanical factor that helps distinguish the mechanical performance of different osteotomy techniques.     

Correction of hallux valgus. Metatarsal osteotomy versus excision arthroplasty

The long-term retrospective results (followup range, 10-22 years) of an uncontrolled series of basal metatarsal closing wedge osteotomies and Keller's excision arthroplasties performed in patients 14 to 40 years of age are analyzed. In the osteotomy group, 34 patients (50 feet) were available for clinical review and 26 patients (37 feet) were available for radiologic review. In the Keller group, 24 patients (37 feet) were reviewed clinically and 23 patients (34 feet) were reviewed radiologically. Patients were assessed using the Hallux Metatarsophalangeal Interphalangeal Scale of the American Foot and Ankle Society, an additional clinical score, weightbearing radiographs, the patient's record, and clinical investigation. Statistical analysis revealed significantly better results of the clinical and radiologic outcomes after osteotomy. In the osteotomy group, the first metatarsal was elevated dorsally in 14 feet (38%). The incidence of varus deformities was higher with basal osteotomy (18% versus 5.4%). Metatarsalgia occurred similarly in both groups (28% versus 27%). It is known that these techniques should be applied to different patient populations. However, they formerly were used for the same indication. This long-term analysis shows that the Keller arthroplasty should be abandoned for the treatment of hallux valgus in young and active patients. The basal metatarsal closing wedge osteotomy is conceptually the correct treatment for hallux valgus deformity for the younger patient; nevertheless, it is technically demanding and is associated with a higher risk of failure. The long-term results of both procedures are unacceptable for the patient and the surgeon. The short and middle-term results of the newer basal type osteotomies, such as the proximal crescentic osteotomy, the proximal chevron osteotomy, or the proximal oblique osteotomy combined with distal soft tissue releases, suggest a more satisfying long-term outcome.     

Multiplanar phalangeal and metatarsal osteotomies for hallux rigidus

Many articles have been published on the various treatments of hallux rigidus/limitus but few, if any, have focused solely on the osteotomies performed in the treatment of this disorder and provided a thorough review of the literature and critique of the procedures. Here, we describe the most commonly used, most widely accepted, and most effective osteotomies in the treatment of hallux limitus/rigidus. Along with this discussion are figures and tables to make the information accessible and user friendly. Among the procedures discussed are Keller arthroplasty, Keller interpositional arthroplasty, Bonney-Kessel, Mayo-Stone, Regnauld, Youngswick, Watermann, Watermann-Green, tricorrectional metatarsal osteotomy, sagittal V, LADO (long-arm decompression osteotomy), Drago, Lambrinudi (plantarflexory closing base wedge osteotomy), sagittal Scarf/sagittal Z, and Weil/Mau/distal oblique osteotomy.     

Mau osteotomy: an alternative procedure to the closing abductory base wedge osteotomy

The authors analyzed the postoperative results of the closing abductory wedge osteotomy and the Mau osteotomy for the reduction of metatarsus primus adductus deformity in terms of radiographic position of the first metatarsal. A review of 21 Mau osteotomies was performed. Data were collected on preoperative and long-term postoperative x-rays to evaluate first metatarsal shortening and elevation.     

Plantar pressure and load in cadaver feet after a Weil or chevron osteotomy

BACKGROUND: Since metatarsal osteotomy was first used to treat metatarsalgia in the early twentieth century, many techniques have been described to accomplish the basic aim of reduction of load transmission through the operated metatarsal and reduction of localized high pressure on the plantar surface of the metatarsal. Our study examined two popular distal metatarsal neck osteotomies used for the relief of central metatarsalgia and the biomechanical changes that result from their use in a cadaver forefoot model. METHODS: After applying 445 N (100 lbs) of axially directed force, we measured plantar pressure using the TekScan HR Mat (TekScan, Inc., South Boston, MA) in twelve paired, thawed, fresh-frozen intact cadaver legs, then after either a Weil or chevron osteotomy of the second metatarsal and finally after the addition of the same osteotomy of the third metatarsal. RESULTS: Load in the forefoot was not significantly affected by the Weil osteotomy. A significant increase in load was produced in the first metatarsal region, and significant decreases in load were produced beneath the operated metatarsal heads after the chevron osteotomy. Average pressure in the contact area of the forefoot showed similar trends; however, load and pressure changes occurred independently, owing to the changes in contact area produced by the osteotomies. No significant changes were observed in the nonoperated metatarsal regions. CONCLUSIONS: In this model, the chevron osteotomy more effectively reduced load and plantar pressure in the operated metatarsal regions; however, increases in load and pressure were observed in the first metatarsal region. The increase in pressure without a change in load in region 3 (third metatarsal) after a Weil osteotomy of the third metatarsal was attributed to the creation of a plantar prominence. This study did not show a reduction in load transmission as a result of the Weil osteotomy, which contradicts the proposed mechanism of clinical benefit. An intact first ray likely prevents transfer of load or pressure to adjacent lesser metatarsals with chevron osteotomy.     

Bunion surgery using locking-plate fixation of proximal metatarsal chevron osteotomies

BACKGROUND: Symptomatic large hallux valgus deformities commonly require surgical intervention with a proximal metatarsal osteotomy. A number of fixation methods have been described for proximal chevron osteotomies; one of the most recent is locking plates. METHODS: We retrospectively reviewed the records of 16 consecutive patients (20 feet) with severe bunion deformities who had locking-plate fixation of proximal chevron osteotomies. Clinical evaluation focused on osteotomy healing, transfer lesions, and hardware-related complications. Preoperative and postoperative radiographic evaluation included the hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), medial 1-2 intermetatarsal distance (MIMD; the amount of narrowing of the foot), sesamoid position, first metatarsal elevation, and metatarsal length change. A postoperative American Orthopaedic Foot and Ankle Society (AOFAS) score was obtained in all patients. RESULTS: The average radiographic improvements were HVA, 16.0 degrees, IMA, 7.6 degrees, and MIMD, 9.0 mm. Sesamoid position improved in 16 of 20 feet. First metatarsal elevation averaged 0.8 degrees, and the average metatarsal shortening was less than 1 mm. The AOFAS score averaged 94.1 points. Two complications were unrelated to plate fixation. CONCLUSIONS: The locking plate held alignment and position of the first ray after chevron osteotomy without clinical evidence of transfer lesions or hardware-related symptoms. Locking plates may improve stability of the proximal metatarsal after a chevron osteotomy for correction of hallux valgus.     

Three-dimensional analysis of different first metatarsal osteotomies in a hallux valgus model

BACKGROUND: This study evaluates and compares three-dimensional (3-D) changes in geometry of the first metatarsal (MT1) independent of soft tissue corrections of 5 common osteotomies: three distal (Chevron, Mitchell, and Wilson), one proximal (Stephens basal), and one combined proximal/distal (Scarf), using standardized synthetic bone models. MATERIALS AND METHODS: A digitizing system was used to measure and record points on the synthetic bone models in 3-D space. Computer vector analysis calculated 3-D rotations and translations of the MT1 head plus the conventional intermetatarsal angle (IMA) and distal metatarsal articular angle (DMAA). RESULTS: The Wilson and Mitchell's osteotomies produced significant shortening (p < 0.001) in contrast to the three other osteotomies. All the osteotomies produced a reduction in the 3-D IMA. The Scarf and Stephens basal osteotomies reduced the DMAA. All of the osteotomies resulted in lateral translations and depression of the MT1 head. While there were no significant (p > 0.05) translational differences between the Scarf and Stephens basal osteotomies, there were rotational differences, with the Stephens basal producing significantly more plantar flexion (p = 0.000) and pronation (p < 0.001) than the Scarf. CONCLUSION: This geometric study indicated many of the MT1 head changes following metatarsal osteotomy to be out-of-plane translational and multiplanar rotations which cannot be determined using AP radiographs alone. CLINICAL RELEVANCE: We advocate judicious choice of osteotomy to achieve the desired correction of hallux valgus in each individual.     

Plantar-to-dorsal compared to dorsal-to-plantar screw fixation for proximal chevron osteotomy: a biomechanical analysis

BACKGROUND: A change in screw orientation in fixing the chevron proximal first metatarsal osteotomy was noted anecdotally to improve fixation strength. The authors hypothesized that plantar-to-dorsal screw orientation would be more stable than the conventional dorsal-to-plantar screw orientation for fixation of the chevron osteotomy. The purpose of this study was to determine if the load-to-failure and stiffness of the chevron type proximal first metatarsal osteotomy stabilized using plantar-to-dorsal screw fixation were greater than with the more conventional dorsal-to-plantar screw fixation method. METHODS: One foot from each of eight matched cadaver pairs was randomly assigned to one of two groups: 1) fixation with a dorsal-to-plantar lag screw or 2) fixation with a plantar-to-dorsal lag screw. A proximal chevron osteotomy was then created using standard technique and the metatarsal was fixed according to previously established method. The bone was potted in polyester resin, and the construct was fitted into a materials testing system machine in which load was applied to the plantar aspect of the metatarsal until failure. The two groups were compared using a two-tailed Student t test. RESULTS: The average load-to-failure and stiffness of the chevron osteotomy fixed with the plantar-to-dorsal lag screw were significantly greater (p < 0.05) than the group fixed with more conventional dorsal-to-plantar lag screws. CONCLUSION: Plantar-to-dorsal screw orientation was more stable than the conventional dorsal-to-plantar screw orientation for fixation of the proximal chevron osteotomy. Plantar-to-dorsal screw orientation should be considered when using the chevron proximal first metatarsal osteotomy.     

Surgical treatment of severe hallux valgus: the state of practice among academic foot and ankle surgeons

BACKGROUND: The purpose of this study was to evaluate the operative procedures used for treatment of severe hallux valgus by academic foot and ankle surgeons practicing in the United States. METHODS: A patient with severe hallux valgus deformity was developed as a hypothetical case: a 50-year-old woman with a severe deformity (intermetatarsal angle = 20 degrees; hallux valgus angle = 42 degrees). The patient was symptomatic with pain, did not improve with conservative measures, and wanted the deformity corrected. This case was sent to academic foot and ankle surgeons in a survey to determine their preferred operative treatment for this case. The overall response rate was 84% (128 of 153). To be included in the study group each surgeon had to have 1) foot and ankle patients comprising 50% or more of his clinical practice and 2) direct responsibility for teaching orthopaedic residents. One hundred and five respondents met the inclusion criteria and formed the study group; however, three surveys with invalid responses were deleted. RESULTS: Fifty-two percent (54 of 102) of the respondents chose a metatarsal osteotomy, 26% (26 of 102) a first metatarsophalangeal (MTP) joint arthrodesis, and 24% (24 of 102) a Lapidus procedure. Two respondents chose both an arthrodesis and a metatarsal osteotomy. Among the 54 respondents who chose metatarsal osteotomies, 24 used a Ludloff, 16 a proximal crescentic, eight a proximal chevron, two a scarf, two a distal chevron, and two other. In addition, secondary procedures to enhance the correction included a Weil osteotomy in 46% (47 of 102) and an Akin osteotomy in 30% (31 of 102). CONCLUSIONS: There was a wide variation in the type of procedure used to correct this severe hallux valgus deformity; approximately 50% of the respondents chose a metatarsal osteotomy, 25% chose a first MTP joint arthrodesis, and 25% a Lapidus procedure.     

Ludloff截骨和基底斜楔形截骨治疗中重度拇外翻的结果比较

目的比较Ludloff截骨和跖骨基底斜楔形截骨治疗中、重度拇外翻的近期临床结果。方法 2008年7月至2009年2月,对21例中、重度拇外翻患者（男2例,女19例）29足实行拇外翻矫形手术。Ludloff截骨术7例（11足）,基底楔形截骨14例（18足）。采用AOFAS评分对患足进行临床功能评价,同时拍负重位的正侧位X线片进行影像学评价。随访结果使用SPSS10.0统计软件包进行处理。结果随访时间5～13个月。最后一次随访时,23足基本无痛（Ludloff截骨9例,基底斜楔形截骨14例）,6足偶有疼痛或轻微疼痛（Ludloff截骨2例,基底斜楔形截骨4例）。有两足拇外翻纠正欠佳（基底斜楔形截骨）,但无疼痛症状。18人,26足基本恢复正常活动。3人,3足（其中1人为双侧,但只有1足有症状,Ludloff截骨术1例,基底截骨术2例）在长距离或长时间行走时出现疼痛。术后AOFAS评分平均为83分（58～92分）。患者自我感觉良好的有17人,24足（Ludloff截骨术10例,基底截骨14例）;感觉较好的2人,3足;感觉一般的2人,2足（Ludloff截骨术1例,基底截骨1例）。对外形满意的19人,26足（Ludloff截骨术10例,基底截骨16例）;一般的1人,1足（Ludloff截骨术）;不满意的1人,1足（基底截骨术）。结论两种手术方式都是治疗中、重度拇外翻可靠有效的方法,但最终的临床结果没有显著不同。     

Biomechanical analysis of two fixation methods for proximal chevron osteotomy of the first metatarsal

Purpose

The proximal chevron osteotomy provides high correctional power. However, relatively high rates of dorsiflexion malunion of up to 17 % are reported for this procedure. This leads to insufficient weight bearing of the first ray and therefore to metatarsalgia. Recent biomechanical and clinical studies pointed out the importance of rigid fixation of proximal metatarsal osteotomies. Therefore, the aim of the present study was to compare biomechanical properties of fixation of proximal chevron osteotomies with variable locking plate and cancellous screw respectively.

Methods

Ten matched pairs of human fresh frozen cadaveric first metatarsals underwent proximal chevron osteotomy with either variable locking plate or cancellous screw fixation after obtaining bone mineral density. Biomechanical testing included repetitive plantar to dorsal loading from 0 to 31 N with the 858 Mini Bionix^® (MTS^® Systems Corporation, Eden Prairie, MN, USA). Dorsal angulation of the distal fragment was recorded.

Results

The variable locking plate construct reveals statistically superior results in terms of bending stiffness and dorsal angulation compared to the cancellous screw construct. There was a statistically significant correlation between bone mineral density and maximum tolerated load until construct failure occurred for the screw construct (r = 0.640, p = 0.406).

Conclusion

The results of the present study indicate that variable locking plate fixation shows superior biomechanical results to cancellous screw fixation for proximal chevron osteotomy. Additionally, screw construct failure was related to levels of low bone mineral density. Based on the results of the present study we recommend variable locking plate fixation for proximal chevron osteotomy, especially in osteoporotic bone.