Characteristic factors of ankle valgus with multiple cartilaginous exostoses

Tibia Valga Correction by Extraperiosteal Fibular Release in Multiple Exostosis Disease

Genu valgum is a frequent deformity encountered in Multiple Hereditary Exostosis (MHE) patients. If left untreated, lower limb deformity leads to poor functional outcomes in adulthood. Our hypothesis was that in some cases, fibular shortening would lead to a lateral epiphysiodesis-like effect on the tibia. We herein report the case of a 6-year-old child with MHE who underwent extraperiosteal resection of the fibula for tibia valga correction. To obtain the lateral release of the calf skeleton, resection included inter-tibio-fibular exostosis along with proximal fibular metaphysis and diaphysis without any osseous procedure on the tibia. Gradual improvement of the valgus deformity occurred during follow-up (HKA from 165° preop to 178° at 27-month follow-up). Lateral release of the fibula led to an increase in the fibula/tibia index (from 93% preop to 96% at follow-up). Studying fibular growth in MHE patients could help understand how valgus deformity occurs in these patients. Even if encouraging, this result is just the report of a unique case. Further research and a larger series of patients are required to assess fibular release as a valuable option to treat valgus deformity in MHE.

Ankle Mortise Instability in Multiple Hereditary Exostoses

Ankle valgus is commonly reported in patients with multiple hereditary exostoses (MHE). We report the characteristics of mortise widening in MHE, its progression over time, and the resultant ankle pain and function at skeletal maturity. Mortise medial space (M), talocrural angle (TC), and tibiotalar angle (TT) measurements were collected on preoperative and last follow-up radiographs. Operative data and complications were recorded. American Orthopaedic Foot and Ankle Society (AOFAS) and short form-36 scores at skeletal maturity were collected. A total of 16 patients (19 ankles) had MHE and mortise widening. Thirteen patients had surgery. Preoperatively, no patient complained of instability. However, 11 ankles (57.9%) were painful and 15 (78.9%) were clinically in valgus. Patients underwent surgery at a mean age of 11.8 ± 2.2 y. Operative interventions included medial distal tibia hemiepiphysiodesis for the majority of patients. There were no statistically significant differences between pre and postoperative M, TC, TT angles. Operative patients showed an improved mean M (5.17 ± 1.17 to 4.63 ± 1.06 mm) and TT (8.71 ± 5.40° to 4.54 ±7.58°), however, neither angle reached normal values. TC representing fibular length-maintained measurements within normal limits (82.2 ± 5.3° to 84.8 ±5.8°). Questionnaires were obtained for 10 (52.6%) ankles. Mean age at questionnaires collection was 19.0 ± 3.6 y. Mean AOFAS score was 74.8 ± 17.6 out of 100. Patients scored 6.5 ± 4.1 out of 10 for alignment, 33.0 ± 6.7 out of 40 for pain, 35.3 ± 9.5 out of 50 for function. All short form-36 scores were above the national mean. Improvement of M and TT angles was modest. TC angle was within normal limits but showed an overall fibular shortening and decreased lateral buttress and potential for talar shift, as reflected in AOFAS score. The underwhelming amount of mortise widening correction achieved may not provide for a stable ankle joint.

Hemiepiphysiodesis Using a Transphyseal Screw at the Medial Malleolus for the Treatment of Ankle Valgus Deformity

Background:

The purpose of this study is to report outcomes of transphyseal screw hemi-epiphysiodesis at the medial malleolus for the treatment of valgus ankle deformity.

Methods:

An institutional review board–approved retrospective review was done of 24 patient charts. Lateral distal tibial angle (LDTA) was measured preoperatively and at final follow-up.

Results:

The average change in LDTA was 8.3 degrees (SD 4.9 degrees; range 0-19 degrees). The average rate of correction was 0.4 degrees per month (SD 0.3; range 0-1.4).

Conclusion:

Medial malleolar transphyseal screw hemiepiphysiodesis is a simple, effective, and safe treatment for valgus ankle deformity in skeletally immature children.

Level of Evidence:

Level IV, case series.

Risk factors for ankle valgus in children with hereditary multiple exostoses: a retrospective cross-sectional study

PURPOSE

The aim of this study was to identify risk factors for ankle valgus in children with hereditary multiple exostoses (HME).

METHODS

We retrospectively reviewed the medical records of patients with HME who were examined at our hospital between 2010 and 2020. Patients' age and sex were recorded along with radiographic variables including mechanical axis deviation (MAD), mechanical lateral distal tibia angle (LDTA), fibula/tibia length ratio (F/T); distal fibula station according to Malhotra's classification, location of exostoses at the ankle joint and fibular neck/physis width (N/P) ratio, which were measured from radiographs. Binary logistic regression analysis was performed to identify significant independent risk factors for ankle valgus.

RESULTS

There were 61 children (20 girls and 41 boys; 122 ankles) who met the inclusion criteria. The mean age was 10.4 years (sd 3.4) and mean LDTA was 83° (sd 7°). Ankle valgus was found in 64 ankles (52%). In addition to younger age, exostoses involving the lateral aspects of the distal tibial and the medial aspect of the distal fibula (odds ratio (OR) = 4.091; 95% confidence interval (CI) 1.065 to 15.712; p = 0.040), F/T ratio < 0.96 (OR = 4.457; 95% CI 1.498 to 13.261; p = 0.007) and N/P ratio > 1.6 (OR = 2.855; 95% CI 1.031 to 7.907; p = 0.043) were associated with an increased risk of developing ankle valgus, while sex and MAD were unrelated to its occurrence.

CONCLUSION

Young age, exostoses involving both the distal tibia and fibula, the F/T ratio < 0.96 and fibular N/P width ratio > 1.6 seemed to be risk factors of developing ankle valgus.

LEVELS OF EVIDENCE

Prognostic studies, IV.

Longitudinal Observation of Changes in the Ankle Alignment and Tibiofibular Relationships in Hereditary Multiple Exostoses

The longitudinal changes in the tibiofibular relationship as the ankle valgus deformity progresses in patients with hereditary multiple exostoses (HME) are not well-known. We investigated the longitudinal changes and associating factors in the tibiofibular relationship during the growing period. A total of 33 patients (63 legs) with HME underwent two or more standing full-length anteroposterior radiographs. Based on the change in ankle alignments, thirty-five patients with an increase in tibiotalar angle were grouped into group V, and 28 patients with a decreased angle into group N. In terms of the change in radiographic parameters, significant differences were noted in the tibial length, the fibular/tibial ratio, and the proximal and distal epiphyseal gap. However, age, sex, initial ankle alignment, location of osteochondroma, and presence of tibiofibular synostosis did not affect the tibiofibular alignment. The tibial growth was relatively greater than the fibular growth and was accompanied by significant relative fibular shortening in the proximal and distal portions. In pediatric patients with HME, age, sex, initial ankle alignment, location of the osteochondroma, and synostosis did not predict the progression of the ankle valgus deformity. However, when valgus angulation progressed, relative fibular shortening was observed as the tibia grew significantly in comparison to the fibula.

Coronal malalignment of lower legs depending on the locations of the exostoses in patients with multiple hereditary exostoses

Backgrounds

Though malalignment of lower legs is a common pathologic phenomenon in multiple hereditary exostoses (MHE), relationship between locations of exostoses and malalignment of lower legs remains unclear. This study examined radiographs of MHE patients in an attempt to evaluate the tendency of coronal malalignment of lower legs with different location of exostoses on lower legs consisting of two parallel long bones.

Methods

Between 2000 and 2017, we retrospectively reviewed the anteroposterior films of the teleo-roentgenographics of 63 patients with MHE. The patients were classified into four different groups depending on the locations of the exostosis, which occurred on both proximal and distal tibiofibular joints (A), proximal tibiofibular joint (B), distal tibiofibular joint (C), and not for the tibiofibular joint area (D). To evaluate the influence of the location of exostoses on coronal malalignment of lower legs, medial proximal tibia angle (MPTA), lateral distal tibia angle (LDTA), and fibular shortening were analyzed for each group.

Results

Significant difference was observed in multiple comparative analyses for each of the four groups. On MPTA radiologic analysis, group A showed greatest value with significant difference compared with groups C and D (vs. (B): p = 0.215; vs. distal joints (C): p = 0.004; vs. (D): p = 0.001). Group B showed significant difference only with group D (vs. distal joints (C): p = 0.388; vs. (D): p = 0.002), but for group C and D showed no significant difference. For LDTA, only group A showed significant difference compared to other groups (p < 0.001). With regard to tibiofibular ratio for evaluation of fibular shortening, group A showed the lowest ratio (vs. (B): p = 0.004; vs. (C): p = 0.655; vs. (D): p < 0.001). Group C also presented the significant lower ratio than group D (p = 0.002).

Conclusions

For evaluation of the coronal malalignment of lower legs in MHE patients, not only ankle around the distal tibiofibular joint but also proximal tibiofibular joint should be examined, in that, lower limb deformity occurred by two parallel long bone which has self-contained joint.

Level of evidence

Level III, retrospective comparative study.

Mitigating Risk of Ankle Valgus From Ankle Osteochondroma Resection Using a Transfibular Approach: A Retrospective Study With Six Years of Follow-Up

To prevent worsening of ankle valgus and functional repercussions, a distal inter-tibiofibular osteochondroma can be removed using a transfibular approach. We evaluated the difference between the preoperative and postoperative tibiotalar tilt at the last follow-up examination and the clinical and radiologic outcomes. We included 10 consecutive ankles that had undergone removal of an osteochondroma using a transfibular approach. The mean patient age was 10.6 years. One ankle was lost to follow-up. The mean postoperative follow-up duration was 5.9 years. The mean preoperative and postoperative tibiotalar tilt was 7.2° and 7.1°, respectively, with no significant difference. The mean postoperative American Orthopaedic Foot and Ankle Society score was 92.4. Tibiofibular synostosis developed in 7 cases. Osteochondroma recurred in 1 case. The transfibular approach stabilizes ankle valgus and is associated with good functional outcomes. However, it is an extensive procedure associated with postoperative synostosis and, thus, should be considered primarily when surgical access for an anterior approach is limited.

Beam Projection Effect in the Radiographic Evaluation of Ankle Valgus Deformity Associated With Fibular Shortening

BACKGROUND

Fibular shortening is one of the most common causes of ankle valgus deformity in children, and is frequently observed in patients with hereditary multiple exostoses (HME). It has been observed that the lateral distal tibial angle (LDTA) measured on the teleoradiograph differs from that on the ankle anteroposterior (AP) radiograph. The effect of the beam projection angle in the measurement of ankle valgus deformity associated with fibular shortening in HME patients was investigated.

METHODS

Fourteen ankles showing valgus deformity associated with fibular shortening from 14 HME patients comprised the short fibula group. Nineteen ankles with normal ankle alignment from 19 patients comprised the control group. The LDTA on the AP radiograph, teleoradiograph, and 3 coronal planes of 3-dimensional computed tomographic scans were measured and compared.

RESULTS

In the short fibula group, the LDTA measured on the ankle AP radiograph was significantly larger than that on the teleoradiograph (79.6±4.3 vs. 75.0±6.2 degrees, P=0.001), whereas there was no significant difference in the control group (P=0.36). In the short fibula group, the LDTAs measured on the 3 coronal planes of 3-dimensional computed tomography showed that the ankle valgus measurement significantly increased from anterior to posterior planes (P=0.001), whereas there was no significant difference in the control group (P=0.85).

CONCLUSIONS

Measurement of ankle valgus deformity depends on the direction of beam projection and ankle valgus deformity is more severe in the posterior coronal plane of the ankle joint. This discrepancy should be taken into consideration in the planning of ankle valgus deformity management.

LEVEL OF EVIDENCE

Level IV-diagnostic.

Is hip dysplasia a common deformity in skeletally mature patients with hereditary multiple exostoses?

BACKGROUND

Various deformities appear in hereditary multiple exostoses (HMEs). Deformities around the knee or ankle joints are easy to detect in this disease because such deformities are visible in appearance. However, deformities in the hip joints of skeletally mature patients are not well understood because their tumors are invisible.

METHODS

To understand deformities around the hip joint in HMEs, we investigated 36 hip joints in 19 skeletally mature patients (12 males, 7 females). The mean age at last X-ray imaging investigation was 29.2 years (14.5-66.5 years). We evaluated the lesions of exostoses around the acetabulum and proximal femur, Wiberg's center-edge angle (CEA), neck-shaft angle (NSA), acetabular depth-width ratio (ADR), and Sharp's acetabular angle.

RESULTS

No exostoses were present in four hips of three cases. Thirty-one hip joints had exostoses on the medial side of the femoral neck. Exostoses existed on the lateral side of the femoral neck in 16 hips. None of the patients had acetabuluar tumors. One patient experienced pain because of impingement between the acetabular rim and medial tumors of the femoral neck. The increase in NSA, which is an index of proximal femoral deformity, was common with a mean NSA of 147.3 °. Two indices of acetabular deformity, Sharp's angle and ADR, were within normal limits with a mean Sharp's angle of 41.3 ° and mean ADR of 269. The average CEA was 29.9 °.

CONCLUSIONS

Hip dysplasia is not necessarily common in skeletally mature patients with HMEs. To determine the possibility of hip dysplasia in skeletally immature patients with HMEs, ADR may be a useful reference index.

[Hereditary multiple exostoses]

BACKGROUND

Hereditary multiple exostosis (HME) is a hereditary autosomal dominant disease in which multiple exostoses occur. Typically, the exostoses are primarily located at the metaphysis and migrate with continued growth towards the diaphysis. Clinical problems are caused by local pain, impingement of muscle tendons and neurovascular structures, malformation - especially in the forearm - and malignant transformation - especially exostoses at the trunc and pelvic girdle.

METHODS

A causal therapy is currently not available. Mechanical irritation is an indication for resection of the exostosis. Axial deviation of the lower extremity is treated according to the same principles as primary malalignments (temporary hemiepiphysiodesis/corrective osteotomy).

RESULTS

The indication for correction of axial deviation at the upper extremity depends on age, extent as well as functional and cosmetic impairment. This should be discussed with the patient in detail. The patient has to be informed about the risk of malignant transformation after cessation of growth. Growing mass or new occurrence of symptoms after end of growth are suspicious and require further diagnostic examinations.

Osteochondromas around the ankle: Report of a case and literature review

INTRODUCTION

An osteochondroma or exostosis is a benign bone tumour consisting of a bony outgrowth covered by a cartilage cap that occurs commonly in the metaphysis of long bones, mainly the distal femur, proximal tibia and proximal humerus.

PRESENTATION OF CASE

We describe an unusual case of a distal tibia osteochondroma affecting the lateral malleolus of a young girl.

DISCUSSION

Most osteochondromas are asymptomatic and seen incidentally during radiographic examination. Osteochondromas are rarely localized in the foot and ankle.

CONCLUSION

Although most of the osteochondromas in children should be treated conservatively until skeletal maturity, those affecting the distal tibia or fibula should be treated with surgical excision in order to prevent ankle deformity, syndesmotic lesions or even fracture due to the expanding nature of this benign tumour.

Correction and recurrence of ankle valgus in skeletally immature patients with multiple hereditary exostoses

BACKGROUND

Ankle valgus is encountered in children with a variety of congenital musculoskeletal disorders, including multiple hereditary exostoses (MHE). Guided growth with temporary distal tibial medial hemiepiphysiodesis (DTMH) may correct the deformity; however, exostoses about the ankle commonly observed in MHE patients may hinder correction and increase the risk of recurrence. Thus, the purpose of this study was to review the outcomes of DTMH in treatment of ankle valgus in MHE versus other diagnosis (non-MHE).

METHODS

Medical records and radiographs of patients undergoing DTMH for ankle valgus between January 1, 2005, and November 1, 2010, at a single pediatric orthopedic hospital were retrospectively analyzed. Radiographs obtained preoperatively and at 6-month intervals postoperatively were reviewed and the tibiotalar angle was measured.

RESULTS

Fifty-eight ankles in 41 patients met inclusion criteria, with minimum follow-up of 12 months (mean, 34 months). Mean age was 10 years (range, 4-14 years). MHE was the most common underlying diagnosis (19 ankles, 33%). The rate of tibiotalar angle correction (mean ± standard deviation) with hardware in place was 0.37 ± 0.28 deg/mo in MHE ankles and 0.51 ± 0.42 deg/mo in non-MHE ankles (P = .161). Following hardware removal, the rate of recurrence was faster in MHE (0.29 ± 0.25 deg/mo) compared with non-MHE ankles (0.12 ± 0.19 deg/mo) (P = .059), and more total recurrent valgus deformity was observed in MHE (7.8 ± 8.2 degrees) than non-MHE ankles (3.4 ± 4.6 degrees) (P = .08) over a similar follow-up period (mean 23.4 vs 23.6 months, respectively), with differences approaching statistical significance.

CONCLUSION

MHE is a common cause of ankle valgus in children. Guided growth interventions in this population can be successful but require special consideration given the potential for relatively gradual deformity correction and rapid recurrence following hardware removal in the skeletally immature.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Total hip and knee arthroplasty in patients with hereditary multiple exostoses

To the authors' knowledge, few reports have been published in the English literature of using total knee arthroplasty and total hip arthroplasty for the treatment of hereditary multiple exostoses. This article describes 2 patients with hereditary multiple exostoses, 1 treated with total hip arthroplasty and 1 treated with total knee arthroplasty. Bony deformities make arthroplasty uniquely challenging in patients undergoing total hip or knee arthroplasty. An expanded metaphysis of the proximal femur, coxa valga deformity, and the presence of hardware from previous reconstructive surgeries can make total hip arthroplasty technically difficult. Substantial bony deformity of the distal femur, valgus deformity of the knee, and sizing issues that necessitate custom implants can make total knee arthroplasty difficult. The most common bony deformities in hereditary multiple exostoses are short stature, limb-length discrepancy, valgus deformity at the knee and ankle, and asymmetry of the pectoral and pelvic girdles. Most reported surgical treatments for patients with hereditary multiple exostoses focus on the pediatric population or the management of malignant transformation of exostoses. Studies that specifically address the conditions associated with knee deformities focus on extra-articular deformity correction rather than arthroplasty.When arthroplasty is necessary in this patient population, an understanding of the commonly occurring deformities can help with preoperative planning and surgical management. All painful lesions must be evaluated for malignant transformation. Bone scans can be useful during workup. All specimens should be sent for pathologic evaluation. Such patients are challenging because of the distorted hip anatomy and valgus knee deformity. The current 2 cases illustrate specific challenges that can be anticipated and underscore key principles for arthroplasty in the management of hereditary multiple exostoses.

Guided growth for ankle valgus

BACKGROUND

Ankle valgus may be insidious and common in a variety of congenital conditions including clubfoot, neuromuscular disorders and others or acquired after fracture, osteotomies, or other manipulations of the lower extremity. This can cause hindfoot pronaton, resulting in lateral impingement and excessive shoe wear. Orthoses do not change the natural history. Medial hemiepiphysiodesis of the tibia is an accepted method of correcting this problem. Difficulties with transmalleolor screw removal prompted us to adopt the tension band method. Our purpose was to outline the technique of using guided growth with a medial tension band plate and discuss the efficacy of this technique.

METHODS

We undertook this retrospective review of 33 patients (57 ankles) who underwent guided growth to correct ankle valgus and were followed until attaining full correction or skeletal maturity. Most of the implants were removed when the ankle was neutral to 5 degrees of varus overcorrection. We obtained weightbearing anteroposterior radiographs of the ankles preoperatively, just before plate removal, and at final follow-up, measuring the lateral distal tibial angle and noting the fibular station. We documented the rate of correction and related complications.

RESULTS

The average age at surgery was 10.4 years (range, 6.1 to 14.6 y) and an average follow-up was 27 months (range, 12 to 57.5 mo). The lateral distal tibial angle improved from an average of 78.7 to 90 degrees at implant removal and measured 88.2 degrees at final follow-up. The rate of correction was calculated to be 0.6 degrees per month. The fibular station remained the same in 36 of 57 ankles and improved in 15 ankles. There were 2 cases of skin breakdown complicated by infection. There were no instances of hardware failure, excessive varus, or premature physeal closure and no patient has required an osteotomy.

CONCLUSIONS

Without appropriate radiographs, ankle valgus may be mistaken for hindfoot valgus and mismanaged accordingly. Guided growth of the distal medial tibia has become our treatment of choice for ankle valgus in the growing child or adolescent. Use of plate epiphysiodesis is safe, well tolerated, may readily be combined with other treatments, and provides a rate of correction comparable to the transmalleolar screw method.

LEVEL OF EVIDENCE

IV, retrospective review, no control series.