Bridging the gap: A technique to avoid limb length discrepancy in arthroplasty for femoral neck fracture - a case report

Equalizing limb length is of paramount importance for optimal outcome in patients undergoing hip arthroplasty(HA). Numerous techniques have been described for avoiding limb length discrepancy (LLD) in patients undergoing HA. However their applicability in patients undergoing HA for neck of femur(NOF) fractures remains questionable due to dissociation between the femur and the head. I hereby describe a novel yet simple technique for better utilization of already established techniques to avoid LLD in NOF fractures undergoing HA. After exposure of hip, the proximal head and neck fragment is extracted taking care not to damage bone at fracture site. Proximal fragment is provisionally fixed to distal fragment in a retrograde manner using 6.5 mm cannulated screws after predrilling over guide wires. Horizontal and vertical offsets are measured. The hip joint is reduced and a mark is made on greater trochanter (GT) utilizing the co-axial stitch method. The joint is dislocated & screws removed.THR is done in a routine manner taking care to establish and recreate native anatomy of hip. Limb length is ascertained utilizing the previous mark on GT. Recreation of proximal femoral anatomy helps in better utilization of already established techniques to avoid LLD and helps us to re-create the native anatomy in HA. It is simple, less time consuming and doesn't require extensive armamentarium or image guidance for its applicability. However it needs to be validated and its advantages might be undermined in old NOF fractures with resorption of the neck or in severely communited fractures.

Error Analysis: How Precise is Fused Deposition Modeling in Fabrication of Bone Models in Comparison to the Parent Bones?

BACKGROUND

Rapid prototyping (RP) is used widely in dental and faciomaxillary surgery with anecdotal uses in orthopedics. The purview of RP in orthopedics is vast. However, there is no error analysis reported in the literature on bone models generated using office-based RP. This study evaluates the accuracy of fused deposition modeling (FDM) using standard tessellation language (STL) files and errors generated during the fabrication of bone models.

MATERIALS AND METHODS

Nine dry bones were selected and were computed tomography (CT) scanned. STL files were procured from the CT scans and three-dimensional (3D) models of the bones were printed using our in-house FDM based 3D printer using Acrylonitrile Butadiene Styrene (ABS) filament. Measurements were made on the bone and 3D models according to data collection procedures for forensic skeletal material. Statistical analysis was performed to establish interobserver co-relation for measurements on dry bones and the 3D bone models. Statistical analysis was performed using SPSS version 13.0 software to analyze the collected data.

RESULTS

The inter-observer reliability was established using intra-class coefficient for both the dry bones and the 3D models. The mean of absolute difference is 0.4 that is very minimal. The 3D models are comparable to the dry bones.

CONCLUSIONS

STL file dependent FDM using ABS material produces near-anatomical 3D models. The high 3D accuracy hold a promise in the clinical scenario for preoperative planning, mock surgery, and choice of implants and prostheses, especially in complicated acetabular trauma and complex hip surgeries.

Undisplaced Intraoperative Fracture Presenting as Early Dislocation with Tapered Wedge Stems in Total Hip Arthroplasty - Case Series and Review of Literature

Introduction:

Periprosthetic fractures and dislocation in the early post-operative period can be disastrous both for the surgeon and the patient. However, undisplaced periprosthetic fractures presenting with dislocation is uncommon. We describe successful management of two cases (one bilateral dislocation and one unilateral dislocation) of undisplaced iatrogenic fractures in total hip arthroplasty (THA) presenting as early dislocation.

Case Report:

Case 1 was a 45-year-old female with osteoarthritis of hip secondary to developmental dysplasia of the hip with bilateral early nontraumatic dislocation with bilateral identical periprosthetic fracture. It was managed by revision to long stem and encirclage wiring. Case 2 presented with early dislocation in the 2^nd week post THA. We found an intertrochanteric fracture intra-operatively with unstable implant. Acetabular component and femoral component revision were done with reconstruction of the greater trochanter.

Discussion:

These fractures could be occult iatrogenic fractures characteristic of taper wedge stems which presented as early nontraumatic dislocation in the post-operative period. The prosthesis subsidence, loss of muscle tension and change of version might be the factors leading to dislocation.

Conclusion:

Unrecognized incomplete intraoperative fracture can occur with tapered wedge uncemented stems which can present as a dislocation in the immediate post-operative period. This will require early revision of the femoral component.

Reference axes for optimal femoral rotational alignment in varus osteoarthritic Indian knees - A CT based study

BACKGROUND

Optimal rotational alignment of femoral component is important for longevity and success of total knee replacement. Whiteside line (WL), posterior condylar axis (PCA) and femoral transepicondylar axis are various intra-operative landmarks to guide femoral rotation. Each of these has its pros and cons. The aims of our study were to assess the relationship of posterior condylar axis and the antero-posterior axis of femur with the surgical epicondylar axis and evaluate whether degree of deformity or severity of osteoarthritis alters the rotational alignment of the femur when posterior condylar axis is taken as a reference. Are we justified in using a 3° external rotation with respect to posterior condylar axis in each knee?

METHODS

The study is a single-centre, CT-based, cross-sectional, radiological study in 56 bilateral osteoarthritic varus Indian knees. The following were deduced using a uniform standardised method: Whiteside-surgical transepicondylar angle and posterior condylar angle. The study population was subdivided based on age, sex, deformity and grade of osteoarthritis.

RESULTS

The mean posterior condylar angle (N = 112) was 3.25 ± 1.379° (95% CI). The posterior condylar angle ranged from '0' degrees to '6' degrees with only 27.7% having an angle of 3°. The mean Whiteside-transepicondylar angle (N = 112) is 89.72 ± 3.537° (95% CI).

CONCLUSIONS

PCA and the WL are comparable in establishing the rotational alignment of the femoral component with respect to the surgical transepicondylar axis. A fixed, 3° external rotation with respect to the PCA is an oversimplification and rotational alignment of the knees should be individualised.

Anatomic variation of palmaris longus and flexor digitorum superficialis of little finger in Indian population

INTRODUCTION

Palmaris longus and flexor digitorum superficialis of the little finger are highly variable anatomically. The tendons vary in different parts of the globe and different regions of the same country. Many studies have negated an association between the tendons. However, most of the studies have a sample size of less than 500 subjects.

AIMS AND OBJECTIVES

The aim was to study the tendons in the Indian population and study the association, if any between the tendons and to test functional significance of the tendons using the Michigan Hand Outcomes Questionnaire.

METHODS AND MATERIAL

It was a single centre cross-sectional study with a sample size of 1500 in the age group of 20-60 years. The subjects were tested for the presence of the tendons and their functionality was assessed by Michigan Hand Outcomes Questionnaire. The data was tabulated and was assessed using SPSS 13.0 software.

RESULTS

Palmaris longus was bilaterally absent in 10.9% and flexor digitorum superficialis of the little finger was bilaterally absent in 42% of the cases. There was a statistically significant association between the tendons when considered bilaterally. The tendons did not have any bearing on the functionality as assessed by the Michigan Hand Outcomes Questionnaire.

CONCLUSIONS

There is significant variability in the palmaris longus and flexor digitorum superficialis tendon to the little finger not only in the different countries but in different regions of the same country. However despite the various clinical and medicolegal aspects concerning both the tendons, they do not have much bearing on the functionality of the hand.

Excellent Functionality Despite Clinico-Radiological Deformity in Osteomyelitis Variolosa - A Case Report

Despite the eradication of smallpox from the world in 1980 the osteo-articular sequelae of smallpox are still occasionally noticed in previously endemic areas. The sequelae of osteomyelitis variolosa may raise a diagnostic challenge to the untrained eyes of the surgeon. We present a case of “osteomyelitis variolosa” in a 70 years old patient. The patient had bilateral dislocation of the elbow joint with multidirectional instability. There was distortion of the articular surfaces and ankylosis of the bilateral proximal radio-ulnar joint. Hypoplasia of the right ulna with short fourth and fifth metacarpals of the left hand and hypoplasia of right fourth metacarpal with cortical thickening was noted radiologically. The patient had minimal disability of his elbows despite the striking radiological abnormality and was functionally independent.

Successful Correction of Idiopathic Bilateral Flexion Deformity of Knee: A Rare Case Report

INTRODUCTION

Bilateral Flexion Deformity commonly results secondary to cerebral palsy, poliomyelitis, haemophilia etc. It is accompanied by valgus deformity and external rotation at knee in long standing cases secondary to the contracture of the iliotibial tract. Flexion deformity at knees is an impediment to the normal ambulation and is difficult to address.

CASE REPORT

A 34 year old male presented with bilateral knee stiffness. He had multifocal tuberculosis and was bed ridden for almost a year and consequently developed bilateral knee flexion deformity of 60o with further flexion upto 120o. Patient was treated with gradual distraction using a modified external fixator and achieved full correction at the end of 6 weeks. At final followup patient was walking comfortably and was able to squat and sit crossed legged.

CONCLUSION

Idiopathic isolated bilateral flexion deformity of knees is very rare and is an impediment to normal ambulation. Arthrodiastasis with indigenously designed fixator using the Ilizarov principle and modified fixator is a simple, efficient and cost effective treatment for flexion deformity of knee.