Medial Displacement Calcaneal Osteotomy: A Comparison of Screw Versus Locking Plate Fixation

A Novel Technique of Medial Displacement Calcaneal Osteotomy Using the Intramedullary Fixation of a Conventional Low-Profile Locking Wedge Plate

BACKGROUND

Postoperative heel pain arising from prominent screw heads is a common complication following medial displacement calcaneal osteotomy (MDCO). This study aims to present the clinicoradiographic outcomes of a novel MDCO technique, wherein intramedullary fixation of a conventional low-profile locking wedge plate is employed.

METHODS

A retrospective analysis, involving a comparison of clinical and radiographic parameters among consecutive patients who underwent MDCO was conducted. The patients were subjected to either intramedullary wedge plate fixation through the osteotomy site (IWPF group, n = 45 cases) or conventional cannulated screw fixation from the heel (CCSF group, n = 51 cases). Radiographic evaluation included measurement of hindfoot alignment angle, alignment ratio, and moment arm. Clinical outcomes were measured with the American Orthopaedic Foot & Ankle Society ankle-hindfoot score, and the Foot and Ankle Ability Measure (FAAM) activities of daily living and sports subscales, before and at 6, 12, and ≥24 months postoperatively. The presence of heel pain was evaluated at the postoperative 6 and 12 months in both groups.

RESULTS

For both groups, a marked enhancement in all 3 radiographic parameters was observed. The extent of correction for all clinicoradiographic parameters demonstrated no statistically significant divergence between the 2 groups. However, the FAAM-Sports scores at the 6-month postoperative juncture exhibited a significant elevation in the IWPF group relative to the CCSF group. Importantly, no patient reported heel pain at postoperative 6 and 12 months in the IWPF group whereas the rates of patients having heel pain at postoperative 6 and 12 months were 56.8% (29 cases) and 33.3% (17 cases), respectively, in the CCSF group.

CONCLUSION

Both techniques yield analogous postoperative clinical and radiographic enhancements. However, the utilization of IWPF promotes a swifter clinical improvement with respect to sports activities when juxtaposed with the CCSF from the calcaneal tuberosity.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

A comparison of treatment between mini T-plate and headless cannulated compression screw in calcaneal osteotomy

PURPOSE

In clinical studies, we discovered that when using headless cannulated compression screw fixation, many patients complain of heel pain and frequently need to have the screws removed, whereas this occurrence is uncommon with plate fixation. This study aims to compare the clinical outcome of a mini T-plate and headless cannulated compression screws in calcaneal osteotomy.

METHODS

We reviewed the medical records of patients who had calcaneal osteotomy performed by one senior chief surgeon in our hospital between January 2014 and May 2021. Thirty-nine patients met the selection criteria: 22 were fixed using a mini T-plate through a modified small "L" incision on the lateral aspect of the calcaneus and 17 were fixed using double screws through an oblique incision on the lateral aspect of the calcaneus. Then, we compared the patient demographics, surgical statistics, and postoperative complications in calcaneal osteotomy between a mini T-plate and double 6.5-mm headless cannulated compressed screws.

RESULTS

Each patient attained radiographic union. The average age was 49.23±13.80 (range: 24-76) years and the average follow-up duration was 47.07±8.64 (range: 36-66) weeks. The average operation duration and times of intraoperative fluoroscopy were significantly lower in the mini T-plate group (P<0.05). There was a savings of $838.88 per patient when using double screws for fixation. The incidence of hardware-related pain and implant removal was lower in the mini T-plate group (P<0.05). There is no significant difference between the two groups in terms of delayed incision healing and clinical neurological complications (P>0.05).

CONCLUSIONS

In calcaneal osteotomy, the operation duration, times of intraoperative fluoroscopy, hardware-related pain, and implant removal rate were lower with mini T-plate fixation than with double screws fixation. Therefore, we consider that the mini T-plate would be a good alternative to double screws in calcaneal osteotomy.

Types of Sliding Calcaneal Osteotomy Fixation: A Systematic Review and Meta-Analysis

Introduction Different methods are used to fix a sliding calcaneal osteotomy for hindfoot varus and valgus deformity. However, information about the effectiveness and limitations of each method is limited. In this meta-analysis, we compare the hardware removal rate, union rate, and complications of three different methods of fixation: plate, headed screw, and headless screw. Methods A systematic review and meta-analysis of published articles were carried out, following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We investigated diverse databases, Web of Science, PubMed, the Cochrane Library, Excerpta Medica database (EMBASE), and Cumulative Index of Nursing and Allied Health Literature (CINAHL), to search articles reporting the use of different calcaneal osteotomy fixations from database inception to October 2021. The primary outcome was the hardware removal rate, and the secondary outcomes of interest were the union rate and complications. Results Of 1,903 articles identified, eight met the inclusion criteria. The highest risk ratio (RR) of the hardware removal rate was detected in the headed screw method (RR: 0.39, 95% confidence interval (CI): 0.26-0.58). However, the highest RR of nonunion was detected in the plate method (RR: 0.02, 95%CI: 0.01-0.07). Regarding complications (infections), the headed screw method presented the highest RR of infection (RR: 0.24, 95%CI: 0.06-0.97). Conclusion This comprehensive review and meta-analysis revealed that the headless screw method may be the most effective fixation option for calcaneal osteotomy with the lowest risk of hardware removal rate, nonunion rate, and complications. Obviously, further studies are needed on a larger number of patients to confirm this finding.

Incidence of Lateral Prominence Pain Following Open Medial Displacement Calcaneal Osteotomy and the Efficacy of Crushplasty as a Preventive Technique

BACKGROUND

There has been concern about lateral prominence pain at the osteotomy site following medial displacement calcaneal osteotomy (MDCO). However, no study has investigated this complication. This study aimed to investigate the incidence of lateral prominence pain following MDCO and examine the efficacy of crushplasty as a surgical technique to minimize this complication.

METHODS

This was a retrospective cohort study in which 137 patients (148 feet) who underwent MDCO were divided into 2 groups by whether they had concurrent crushplasty at the time of MDCO (crushplasty [n = 81] vs noncrushplasty group [n = 67]). Crushplasty was performed by flattening the bony step-off using a rongeur and bone impactor. Lateral prominence pain was defined as pain or irritating symptoms over the osteotomy site that persisted over 12 months after MDCO. The overall incidence of lateral prominence pain after MDCO and within each group was investigated. Multiple logistic regression analysis was used to determine the influence of possible risk factors on the development of postoperative lateral prominence pain.

RESULTS

The overall incidence of lateral prominence pain was 9.5% (14 of 148): 3.4% (3 of 87) in the crushplasty group, and 18% (11 of 61) in the noncrushplasty group, and χ² analysis showed a statistically significant relationship between crushplasty and lateral prominence pain (P < .05). A relationship between the amount of medial displacement and the development of lateral prominence pain was observed in the noncrushplasty group (OR = 5.31, 95% CI 2.35-16.4, P < .05), but this was not observed in the crushplasty group (P = .641). The amount of medial displacement was an independent risk factor for the development of lateral prominence pain (OR = 2.72, 95% CI 1.54-4.79, P < .05), and concurrent crushplasty had a negative relationship with lateral prominence pain development (OR = 0.12, 95% CI 0.03-0.57, P < .05).

CONCLUSION

This study revealed that lateral prominence pain is a significant complication of MDCO, especially in the setting of a larger displacement. The crushplasty following MDCO may minimize this complication, particularly when a greater degree of hindfoot correction is attempted.

Adult-Acquired Flatfoot Deformity: Combined Talonavicular Arthrodesis and Calcaneal Displacement Osteotomy versus Double Arthrodesis

Background: Adult-acquired flatfoot deformity due to posterior tibial tendon dysfunction (PTTD) is one of the most common foot deformities among adults. Hypothesis: Our study aimed to confirm that the combined procedures of calcaneal displacement osteotomy and talonavicular arthrodesis are equivalent to double arthrodesis. Methods: Between 2016 and 2020, 41 patients (13 male and 28 females, mean age of 63 years) were retrospectively enrolled in the comparative study. All deformities were classified into Stages II and III of PTTD, according to Johnson and Strom. All patients underwent isolated bony realignment of the deformity: group A (n = 19) underwent calcaneal displacement osteotomy and talonavicular arthrodesis, and group B (n = 23) underwent double arthrodesis. Measurements from the Foot Function Index-D (FFI-D) and the SF-12 questionnaire were collected, with a comparison of pre- and post-operative radiographs conducted. The mean follow-up period for patients was 3.4 years. Results: The mean FFI-D was 33.9 (group A: 34.5; group B: 33.5), the mean SF-12 physical component summary was 43.13 (group A: 40.9; group B: 44.9), and the mean SF-12 mental component summary was 43.13 (group A: 40.9; group B: 44.9). The clinical data and corrected angles showed no significant intergroup differences. Conclusion: Based on the available data, our study confirmed that the combined procedures of talonavicular arthrodesis and calcaneal shift, with preservation of the subtalar joint, can be considered equivalent to the established double arthrodesis, with no significant differences in terms of clinical and radiological outcomes.

Adult Acquired Flatfoot Deformity

Adult acquired flatfoot deformity (AAFD) is a condition commonly seen by orthopaedic surgeons. Posterior tibial tendon dysfunction is thought to be the initial pathoanatomic etiology that leads to this deformity. Successful resolution of the pain associated with AAFD can be achievable with nonsurgical methods. Patients who continue to have pain or functional limitations despite nonsurgical treatment can find improvement with appropriately selected surgical interventions. This article addresses new advances in treatment based on the stage of AAFD and will identify areas of continued development with a focus on surgical management. The literature continues to evolve as demonstrated by a recent update regarding the nomenclature and treatment of this condition to progressive collapsing flatfoot deformity. Future goals of research include understanding the natural history of the disease, from asymptomatic to symptomatic, and studying a wide array of newer treatments and implants that have not been prospectively evaluated.

Biomechanical comparisons of different diagonal screw designs in a novel embedded calcaneal slide plate

BACKGROUND

Medial displacement calcaneal osteotomy (MDCO) is frequently used for the surgical correction of flatfoot. This study aims to investigate the biomechanical effect of the different diagonal screw design on a novel-designed embedded calcaneal plate for MDCO using finite element analysis (FEA), mechanical test and digital image correlation (DIC) measurement.

METHODS

Four groups according to the varied implanted plate were set as control group (Group 1), non-diagonal screw (Group 2), one-diagonal screw (Group 3), and two-diagonal screws groups (Group 4). For FEA, A 450 N load was applied to on the anterior process of the calcaneus from top to bottom. Observational indices included the stress on the cortical and cancellous bone of the calcaneus surrounding the implant, the plate itself as well as screws, and the displacement of the overall structure. In addition, this study also used in vitro biomechanics test to investigate the stiffness of the structure after implantation, and used DIC to observe the displacement of the calcaneus structure after external force.

RESULTS

Under a simulated load in FEA, there are significant overall instability and high stress concentration on the calcaneal surrounding host bone and the plate/screws system, respectively, in group 2 compared with other groups. Regard to the mechanical testing with DIC system, significant increased rotation stability, maximum force and stiffness with the addition of diagonal screws. In comparison to Group 2, the increase of 112% and 157% in maximum force as well as 104% and 176% in stiffness were found in Group 3 and 4, respectively.

CONCLUSION

For reducing stress concentration and enhancing overall stability, more than one-diagonal screw design is recommended and two-diagonal screws design will be superior. This study provided biomechanical references for further calcaneal implants design to prevent clinical failure after MDCO.

Calcaneal Osteotomies in the Treatment of Progressive Collapsing Foot Deformity. What are the Restrictions for the Holy Grail?

The progressive collapsing foot deformity is a complex three-dimensional deformity, including valgus malalignment of the heel. The medial displacement calcaneal osteotomy is an established surgical procedure reliably resulting in an efficient correction of the inframalleolar alignment. However, complications are common, including undercorrection of underlying deformity, progression of hindfoot osteoarthritis and/or deformity, and/or symptomatic hardware.

Medial Displacement Calcaneal Osteotomy for Unilateral Adult Acquired Flatfoot: Effects of Minimally Invasive Surgery on Pain, Alignment, Functioning, and Quality of Life

We aimed to assess the effects of medial displacement calcaneal osteotomy (MDCO) through a minimal skin incision in terms of pain, function, and alignment in patients with unilateral adult acquired flatfoot. American Orthopedic Foot and Ankle Society (AOFAS) hindfoot scale and Numeric Pain Rating Scale (NPRS) were assessed as outcomes at the baseline (T0), at 6 months (T1), and at 1 year (T2) from surgery. We analyzed data of 20 patients (7 male and 13 female), mean aged 46.6 ± 5.34 years, showed significant differences after 6 months in terms of AOFAS total score (44.30 ± 7.39 vs 96.50 ± 4.89; p = .0001), AOFAS subitems (p < .001), and pain (NPRS: 7.95 ± 1.36 vs 1.05 ± 1.05; p = .0001). At 1 year after surgery (T2), all outcome measures still significantly differ from baseline (p < 01). Therefore, percutaneous MDCO through a minimal skin incision seemed to be safe and effective in the middle and long term in reducing pain and improving function and alignment in patients with unilateral adult acquired flatfoot.

Medial displacement calcaneal osteotomy versus lateral column lengthening to treat stage II tibialis posterior tendon dysfunction, a prospective randomized controlled study

PURPOSE

Adult-acquired flatfoot deformity (AAFD) requires optimum planning that often requires several procedures for deformity correction. The objective of this study was to detect the difference between MDCO versus LCL in the management of AAFD with stage II tibialis posterior tendon dysfunction regarding functional, radiographic outcomes, efficacy in correction maintenance, and the incidence of complications.

PATIENT AND METHODS

42 Patients (21 males and 21 females) with a mean age of 49.6 years (range 43-55), 22 patients had MDCO while 20 had LCL. Strayer procedure, spring ligament plication, and FDL transfer were done in all patients. Pre- and Postoperative (at 3 and 12 months) clinical assessment was done using AOFAS and FFI questionnaire. Six radiographic parameters were analyzed, Talo-navicular coverage and Talo-calcaneal angle in the AP view, Talo- first metatarsus angle, Talo-calcaneal angle and calcaneal inclination angle in lateral view and tibio-calcaneal angle in the axial view, complications were reported.

RESULTS

At 12 months, significant improvement in AOFAS and FFI scores from preoperative values with no significant difference between both groups. Postoperative significant improvements in all radiographic measurements in both groups were maintained at 12 months. However, the calcaneal pitch angle and the TNCA were better in the LCL at 12 months than MDCO, 17̊±2.8 versus 13.95̊±2.2 (p=0.001) and 13.70̊±2.2 versus 19.05̊±3.2 (p<0.001) respectively. 11 patients (26.2%) had metal removal, seven (16.6%) in the MDCO, and four (9.6%) in the LCL. Three (7.1%) in the LCL group had subtalar arthritis, only one required subtalar fusion.

CONCLUSION

LCL produced a greater change in the realignment of AAFD, maintained more of their initial correction, and were associated with a lower incidence of additional surgery than MDCO, however, a higher incidence of degenerative change in the hindfoot was observed with LCL.

Outcomes of Idiopathic Flexible Flatfoot Deformity Reconstruction in the Young Patient

Background:

Operative correction of flatfoot deformity has been well studied in the older population. There is a subset of younger patients without congenital foot deformity that also develop a collapsing flatfoot. However, assessment of outcomes across age groups is limited, especially in the young demographic. The purpose of our study was to compare operative outcomes of flatfoot reconstruction between these 2 age groups.

Methods:

Seventy-six feet (41 left, 35 right) in 71 patients who underwent flexible flatfoot reconstruction were divided into 2 groups based on age: ≤30 years (n = 22) and >30 years (n = 54). Exclusion criteria included congenital causes of flatfoot (tarsal coalition, vertical talus, overcorrected clubfoot). Average age was 20.8 years (range, 14-30) and 55.4 years (range, 35-74) in the younger and older cohorts, respectively. Preoperative and minimum 2-year postoperative Patient-Reported Outcomes Measurement Information Systems (PROMIS) scores were compared. Five radiographic parameters were assessed pre- and postoperatively: talonavicular coverage angle, lateral talo–first metatarsal angle, lateral talocalcaneal angle, calcaneal pitch, and hindfoot moment arm. Procedures performed and incidence of minor (removal of symptomatic hardware) and major (revision) reoperations were compared.

Results:

Younger patients were less likely to undergo flexor digitorum longus transfer, first tarsometatarsal fusion, spring ligament repair, and posterior tibial tendon repair (all P < .05). Both younger and older cohorts demonstrated significant improvement in multiple PROMIS domains at an average follow-up of 30.6 (range, 24-44) and 26.8 (range, 24-45) months, respectively ( P = .07). Younger patients demonstrated significantly higher pre- and postoperative Physical Function (mean difference postoperatively, 4.6; 95% confidence interval, 1.5-7.8; P = .03). There were no differences in radiographic parameters postoperatively. There were 8 (36.4%) reoperations (all minor) in the younger group, and 21 (38.9%) reoperations (6 major, 15 minor) in the older group ( P = .84).

Conclusion:

Our data suggest that age may play a role in clinical outcomes, procedures indicated, and subsequent corrective reoperations. Younger patients maintained greater physical function with comparable radiographic correction, with less frequent indication for tendon transfers, arthrodesis, and additional corrective surgeries.

Level of Evidence:

Level III, retrospective comparative study.

Review of Calcaneal Osteotomies Fixed With a Calcaneal Slide Plate

BACKGROUND

The calcaneal slide osteotomy is a common procedure used for the surgical correction of heel varus and valgus deformities. A variety of fixation methods exist including screws and plates. The literature shows a high rate of hardware prominence with screws leading to subsequent removal of hardware. Few studies have examined the use of plates for fixation of a calcaneal osteotomy. The purpose of this study was to assess outcomes following fixation of a calcaneal osteotomy with a calcaneal slide plate.

METHODS

This is a retrospective consecutive case series of all patients who underwent either a medial or lateral calcaneal slide osteotomy using the specialized calcaneal slide plate between September 2013 and December 2018 by a single surgeon. The primary outcome measures were the rate of hardware removal, healing of the calcaneal osteotomy, and any associated complications such as infection or incision healing delays. Patient baseline demographics and procedure-related data were recorded. The minimum follow-up was 4 months. A total of 81 procedures were performed using this calcaneal slide plate.

RESULTS

All of the patients had one or more additional procedures at the same time as the calcaneal osteotomy. All of the calcaneal osteotomies healed without displacement. Only 1 patient (1.2%) returned to the operating room and had removal of the calcaneal slide plate, which was after osteotomy union for an infected wound. There were no cases of hardware failure or removal due to it being symptomatic.

CONCLUSION

A specialized calcaneal slide plate was an effective fixation device for both medial and lateral calcaneal slide osteotomies for a variety of foot and ankle conditions. The union rate was 100% and none of the patients had hardware symptoms, which is an improvement on published reports of symptomatic hardware after calcaneal slide osteotomy.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Flexor digitorum longus tendon transfer to the navicular: tendon-to-tendon repair is stronger compared with interference screw fixation

PURPOSE

To assess whether early rehabilitation could be safe after flexor digitorum longus (FDL) tendon transfer, the current biomechanical study aimed to measure tendon displacement under cyclic loading and load to failure, comparing a traditional tendon-to-tendon (TT) repair with interference screw fixation (ISF).

METHODS

24 fresh-frozen cadaveric below knee specimens underwent FDL tendon transfer. In 12 specimens a TT repair was performed via a navicular bone tunnel. In a further 12 specimens ISF was performed. Using a materials testing machine, the FDL tendon was cycled 1000 times to 150 N and tendon displacement at the insertion site measured. A final load to failure test was then performed. Statistical analysis was performed using two-way ANOVA and an independent t test, with a significance level of p < 0.05.

RESULT

No significant difference in tendon displacement occurred after cyclic loading, with mean tendon displacements of 1.9 ± 1.2 mm (mean ± SD) in the TT group and 1.8 ± 1.5 mm in the ISF group (n.s.). Two early failures occurred in the ISF group, none in the TT group. Mean load to failure was significantly greater following TT repair (459 ± 96 N), compared with ISF (327 ± 76 N), p = 0.002.

CONCLUSION

Minimal tendon displacement of less than 2 mm occurred during cyclic testing in both groups. The two premature failures and significantly reduced load to failure observed in the ISF group, however, indicate that the traditional TT technique is more robust. Regarding clinical relevance, this study suggests that early active range of motion and protected weight bearing may be safe following FDL tendon transfer for stage 2 tibialis posterior tendon dysfunction.

The incision strategy for minimizing sural nerve injury in medial displacement calcaneal osteotomy: a cadaveric study

Background

The skin incision for medial displacement calcaneal osteotomy (MDCO) often damages the sural nerve. We aimed to identify the practical reference area in which the surgeon can incise the skin to minimize the injury of the sural nerve during MDCO.

Methods

The foot and ankles of 20 cadavers were dissected. The landmarks were the following four anatomical references: point A, the tip of the lateral malleolus; point B, the inferior margin of the calcaneus on the vertical line through point A; point C, the posteroinferior apex of the calcaneus; and point D, the lateral border of the Achilles tendon on the horizontal line through point A. The distances from the sural nerve to points A and B in the vertical direction (lines D1 and D2, respectively), to points A and C in the diagonal direction (lines D3 and D4, respectively), and to points A and D in the horizontal direction (lines D5 and D6, respectively) were measured.

Results

The median ratios of D1 to D1+D2, D3 to D3+D4, and D5 to D5+D6 were 0.34 (range 0.25 to 0.45), 0.23 (range 0.16 to 0.33), and 0.38 (range 0.26 to 0.50), respectively.

Conclusions

The distance ratios according to easily identifiable references would be a more practical incision strategy for surgeons to minimize sural nerve injury in both open and minimally invasive/percutaneous MDCO.

A comparison of union rates and complications between single screw and double screw fixation of sliding calcaneal osteotomy

BACKGROUND

The number of screws used for sliding calcaneal osteotomy fixation has not been examined in the literature. The purpose of this paper is to examine this topic.

METHODS

Retrospective chart review was performed on 190 patients who met selection criteria. We compared complication risk for single versus double screw, headed versus headless screw, and short versus longitudinal incision cases.

RESULTS

The mean age was 48.4 (18-83) years and average follow up was 28 (12-150) weeks. All cases achieved radiographic union. Overall complication rate was 19.5% (37/190). Risk of complication did not differ significantly between single and double screw (RR: 1.170; 95% CI: 0.66-2.09; p=0.594) or short and extended incision groups (RR: 0.868; 95% CI: 0.42-1.80; p=0.704). Risk of complication differed significantly between headed and headless screw fixation (RR: 5.558; 95% CI: 2.69-11.50; p<0.0001).

CONCLUSIONS

Single screw fixation of sliding calcaneal osteotomy achieves similar outcomes as double screw fixation. Headless screws are advantageous for minimizing hardware pain and subsequent hardware removal.

Adult-Acquired Flatfoot Deformity

Adult-acquired flatfoot deformity (AAFD) comprises a wide spectrum of ligament and tendon failure that may result in significant deformity and disability. It is often associated with posterior tibial tendon deficiency (PTTD), which has been linked to multiple demographic factors, medical comorbidities, and genetic processes. AAFD is classified using stages I through IV. Nonoperative treatment modalities should always be attempted first and often provide resolution in stages I and II. Stage II, consisting of a wide range of flexible deformities, is typically treated operatively with a combination of soft tissue procedures and osteotomies. Stage III, which is characterized by a rigid flatfoot, typically warrants triple arthrodesis. Stage IV, where the flatfoot deformity involves the ankle joint, is treated with ankle arthrodesis or ankle arthroplasty with or without deltoid ligament reconstruction along with procedures to restore alignment of the foot. There is limited evidence as to the optimal procedure; thus, the surgical indications and techniques continue to be researched.

[Biomechanical comparison of three kinds of fixation instruments for calcaneal osteotomy]

Objective

To compare the biomechanical characteristics of self-made nickel-titanium shape memory alloy stepped plate with calcaneal plate and cannulated compression screws in fixing calcaneal osteotomy.

Methods

Calcaneal osteotomy was operated on 6 fresh-frozen lower limbs collected from donors. Then three kinds of fixation materials were applied in random, including the self-made nickel-titanium shape memory alloy stepped plate (group A), calcaneal plate (group B), and cannulated compression screws (group C). Immediately after fixation, axial loading of 20-600 N and 20 N/s in speed was introduced to record the biomechanical data including maximum displacement, elastic displacement, and maximum load. Then fatigue test was performed (5 Hz in frequency and repeat 3 000 times) and the same axial loading was introduced to collect the biomechanical data. Finally, the axial compression stiffness before and after fatigue test were calculated.

Results

There was no significant difference in the axial compression stiffness between pre- and post-fatigue test in each group ( P>0.05). However, the axial compression stiffness was significant higher in group A than that in groups B and C both before and after fatigue test ( P<0.05). No significant difference was found between group B and group C ( P>0.05).

Conclusion

Self-made nickel-titanium shape memory alloy stepped plate is better than calcaneal plate and cannulated compression screws in axial load stiffness after being used to fix calcaneal osteotomy.