Custom total hip arthroplasty in skeletal dysplasia

Hip Arthroplasty in Patients with Osteogenesis Imperfecta

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Osteogenesis imperfecta (OI) is a rare congenital disorder that affects connective tissue.

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Modern medicine has mitigated the mortality that is associated with OI, allowing patients to live a near-normal life span.

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The degenerative process in OI is probably accelerated because of subclinical intra-articular fractures, joint laxity, and distorted femoral and acetabular anatomy.

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Total hip arthroplasty is seldom performed in patients with OI; it is technically difficult due to bone fragility, deformity, soft-tissue alteration, acetabular protrusion, the risk of intraoperative and postoperative fractures, and joint laxity.

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This review highlights that patients with OI need hip arthroplasty procedures at an early age and that early revision surgery can be expected. New-generation uncemented implants may improve implant survivorship.

Total hip arthroplasty combined with subtrochanteric shortening osteotomy for Crowe type IV hip dysplasia in dwarfism: a case report

Dwarfism is a condition of extreme short stature. Total hip arthroplasty (THA) in patients with dwarfism is a very demanding procedure due to their specific joint deformity and small bone size, which increases the technical difficulty of the THA procedure in such patients with hip dysplasia. This current case report describes a 29-year-old female patient that was admitted due to shortening of the right lower limb, as compared with the contralateral side, which had been present for 18 years. She also complained of pain in the right hip that had been present for 2 months. The hip pain was aggravated by physical exertion, but relieved by rest. She had pituitary dwarfism without mental retardation or delayed sexual development and Crowe type IV dysplasia of the right hip. A THA combined with femoral shortening osteotomy was undertaken, which resolved the pain symptoms and improved her ability to undertake activities of daily living such as walking without pain. Dwarfism with hip dysplasia is a rare but extremely challenging problem that can be successfully treated with THA combined with femoral shortening osteotomy using an S-ROM stem.

Joint Replacements in Individuals With Skeletal Dysplasias: One Institution's Experience and Response to Operative Complications

BACKGROUND

Skeletal dysplasias are a heterogeneous group of >400 genetic disorders characterized by abnormal bone growth. Many individuals experience joint pain and limitation, coming to require joint replacement much earlier than the average-statured population. In addition, prosthesis survival rate is less in the dysplastic population. The purpose of this study is to identify risk factors for surgery and provide recommendations to improve surgical outcomes.

METHODS

This a retrospective review of 29 individuals with a skeletal dysplasia who had 64 joint replacements between April 1985 and January 2019 at a single institution. We collected demographics, physical examination, medical history, imaging studies, surgical indication, and complications.

RESULTS

Spondyloepiphyseal dysplasia was the most common skeletal dysplasia (7), followed by pseudoachondroplasia (4) and multiple epiphyseal dysplasia (4). Average age of the cohort was 40.6 years (range 14-64). Hip arthroplasty (34) was the most commonly performed surgery. The majority of arthroplasties (75%) required custom components. Complication rate was 37.3%, most commonly pulmonary embolism (3) and pneumonia (3). Most complications (81.8%) occurred in individuals with either a pre-existing cardiopulmonary comorbidity or lumbar/sacral deformity. Body mass index did not correlate with complication severity (R = -0.042, P = .752) or rate (R = 0.006, P = .963).

CONCLUSION

Surgical complications are highest in patients with pre-existing cardiopulmonary conditions. Body mass index does not predict complications in this cohort. Preoperative evaluations for individuals with skeletal dysplasias should include comprehensive work-up of spine issues and extraskeletal systems that present an operative risk. Intraoperative protocol should include special consideration for placement on the table, airway maintenance, and spinal cord monitoring in select cases.

Perioperative Outcomes and Complications After Primary Total Hip Arthroplasty in Patients With Disproportionately Short Stature: A Matched Cohort Analysis

BACKGROUND

This study compared (1) perioperative outcomes, (2) postoperative complications, and (3) reoperation rates after primary total hip arthroplasty (THA) between short stature patients and matched control patients.

METHODS

A review of primary THA patients from 2012 to 2017 using an institutional database was conducted. This yielded 12,850 patients of which 108 were shorter than 148 cm. These patients were matched 1:1 by age (P = .527), gender (P = .664), and body mass index (P = .240) to controls. The final study population with minimum 1-year follow-up that was included for analysis comprised 47 patients in the short stature cohort and 57 patients in the control cohort. The following outcomes/complications were compared: operative times, lengths of stay (LOSs), intraoperative fractures, minor complications, 90-day readmissions, and revisions.

RESULTS

Operative times were significantly longer in the short stature cohort than in the matched control cohort (133 ± 65 minutes vs 104 ± 30 minutes, P = .005). In addition, hospital LOS was slightly longer in the short stature group than in the matched control groups (3.2 ± 1.5 days vs 2.6 ± 1.0, P = .017). Rates of intraoperative fractures (P = 1.000), minor complications P = .406), 90-day readmissions (P = .5000), and revision (P = .202) were similar between the short stature and control cohorts.

CONCLUSION

Patients with disproportionately short stature had longer operative times and slight longer LOS. However, complication and readmission rates were similar. Future studies with larger sample sizes are warranted to confirm these findings and further evaluate implant survivorship in this unique THA patient population.

Patients with musculoskeletal dysplasia undergoing total joint arthroplasty are at increased risk of surgical site Infection

INTRODUCTION

Musculoskeletal dysplasias (MSD) are inherited conditions of abnormal cartilage and bone development and remodeling which include, amongst others, multiple epiphyseal dysplasia (MED), spondyloepiphyseal dysplasia (SED), achondroplasia, and hypochondroplasia. The aim of this study was to compare patient characteristics and in-hospital complications between MSD and non-MSD patients undergoing total joint arthroplasty (TJA).

HYPOTHESIS

MSD patients undergoing TJA are at increased risk of in-hospital post-operative complications and mortality compared to non-MSD patients.

MATERIALS AND METHODS

The Nationwide Inpatient Sample (NIS) from the years 2005 to 2014 was used for this retrospective cohort study. International Classification of Diseases, Clinical Modifications (ICD-9-CM) procedure codes identified primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) procedures and were used to separate MSD and non-MSD patients. Patients with trauma or malignancy as primary diagnoses, non-elective procedures, revision procedures, and concurrent bilateral surgeries were excluded. Patients were compared using linear regression or multivariate logistic regression analysis to control for confounders. All statistical analyses were performed taking into account the NIS sampling scheme and associated sampling weights.

RESULTS

A total of 1,255 patients comprised the MSD group and 8,027,181 patients the non-MSD group. MSD patients were younger than non-MSD patients (50.9 vs. 65.8 years, p<0.001), with less comorbidities including: hypertension (40.2% vs. 64.5%, p<0.001), coronary artery disease (5.5% vs. 12.9%, p<0.001), diabetes mellitus (9.4% vs. 19.0%, p<0.001), and hypothyroidism (7.8% vs. 14.7%, p=0.002). MSD patients had higher risks of surgical site infection (0.8% vs. 0.2%; OR, 4.16; 95% CI, 1.03-16.75; p=0.044), and perioperative hemorrhage (2.1% vs. 0.7%; OR, 3.20; 95% CI, 1.32-7.76; p=0.010).

DISCUSSION

MSD patients undergoing TJA were younger with less co-morbidity compared to non-MSD patients, and had no significant difference in overall perioperative medical and surgical complication rates. However, they are at increased risk for surgical site infection and perioperative hemorrhage possibly due to the anatomical complexity encountered.

LEVEL OF EVIDENCE

III, Retrospective Cohort.

[Total hip arthroplasty in young patients : Bearings and custom-made prostheses]

BACKGROUND

Carefully and correctly implanted components are the prerequisite for the lifespan of a prosthesis. Whether higher levels of activity lead to prior failure of total hip arthroplasty in young patients is controversially discussed. The right choice of bearings is still of great relevance.

BEARINGS

Ceramic-on-ceramic as well as polyethylene-on-ceramic bearings achieve comparable results, although ceramic-on-ceramic bearings should be avoided in patients with high demands on their range of motion. Polyethylene-on-metal bearings also show good clinical results, if corrosion between head and stem is absent. Metal-on-metal bearings lead to adverse systemic effects due to metal wear and should be implanted in individual cases only, e. g. as hip resurfacing. Alternative bearings have to give proof of effectivity first. Custom-made prostheses constitute an option for young patients with special conditions of hip anatomy. Planning and study results of these prostheses are elucidated in this review article.

A 20-year follow-up evaluation of total hip arthroplasty in patients younger than 50 using a custom cementless stem

AIM

The purpose of this study is to report the 20-year follow-up of a continuous series of 232 total hip arthroplasties (THAs) performed in patients aged less than 50 at the index surgery.

PATIENTS AND METHODS

This is a retrospective monocentric study which reports the clinical, radiographical and survival results of 232 THAs performed with a custom cementless femoral stem in 212 patients evaluated at follow-up ranging from 14 to 27 years.

RESULTS

At the time of follow-up, the mean Harris Hip Score was 94.1 (range 48-100). The Hip disability and Osteoarthritis Outcome Score was >80 points in all 5 categories for 146 patients (68.9%). 18 hips (8.5%) showed radiographical femoral abnormalities. 23 hips (10.8%) underwent revision of the implants. 13 were isolated cup revisions. 3 more hips had bipolar revisions for aseptic loosening at 15, 20 and 21 years. Taking stem revision for aseptic loosening as an endpoint, survivorship was 96.8% at 20 years (95% confidence interval, 95.1-98.5; patients at risk 76) and 94.5% at 25 years (91.7-97.3; patients at risk 12).

CONCLUSIONS

The results of this study confirm that THA using this custom-designed stem can provide excellent clinical and radiographical outcomes at a mean follow-up of 20 years in patients younger than 50. The individual 3D femoral stem and prosthetic neck has been able to restore extra- and intramedullary functional anatomy in this young and active cohort of patients.

Midterm Survivorship and Complications of Total Knee Arthroplasty in Patients With Dwarfism

BACKGROUND

Dwarfism is associated with skeletal dysplasias and joint deformities that frequently result in osteoarthritis requiring treatment with total knee arthroplasty (TKA). These surgeries can be challenging because of alignment deformities, poor bone stock, and smaller components. This study aims to compare TKA implant survivorship and complications between dwarf and nondwarf patients.

METHODS

A retrospective case-control study was performed from 1997-2014 evaluating 115 TKAs in patients under the height threshold of 147.32 cm. This cohort was compared with 164 patients of normal height. Medical records were reviewed for demographics, surgical characteristics, and outcomes. All cases had 2-year minimum follow-up.

RESULTS

The revision rate was 8.7% in dwarfs compared with 3.7% in controls (P = .08). The 2-, 5-, and 10-year implant survivorship in dwarfs was 96.4%, 92.5%, and 90.2%, respectively; and 96.6%, 95.6%, and 94.8% for controls, respectively (P = .24). Dwarfs underwent significantly more manipulations for arthrofibrosis (P = .002). There was greater femoral (17.4% vs 2.1%, P < .01) and tibial (6.5% vs 2.7%, P < .01) component overhang in dwarfs compared with controls.

CONCLUSION

Despite a 2-fold increase in the revision rate of the dwarf cohort, the midterm survivorship is comparable between the dwarf and nondwarf patients. However, dwarfs were more likely to become stiff and undergo manipulation; the increased propensity for stiffness may be associated with oversized components, as evidenced by greater component overhang. Surgeons should be aware of this increased risk and may consider using smaller or customized implants to account for the morphological differences in this patient population.

Survivorship and complications of total hip arthroplasty in patients with dwarfism

BACKGROUND

Total hip arthroplasty (THA) is a common procedure used to treat bony hip deformities and skeletal dysplasia in dwarfism. These surgeries are often more difficult than conventional THA as they may involve malformed joints and poor bone quality, and may require smaller prostheses. This study aims to investigate whether implant survivorship and revision rates vary among patients with and without dwarfism undergoing THA.

METHODS

A retrospective case-control study was performed for 102 THAs completed between 1997 and 2014 in patients under the height threshold of 147.32 cm. This cohort was matched 1:1.5 with patients of normal height with respect to age, gender, year of surgery, and Charlson comorbidities. All cases had a minimum follow-up of 1 year. A chart review was performed to identify patient and surgical characteristics, including outcomes. Radiographs were assessed for deformity, loosening, and periprosthetic fractures among other factors.

RESULTS

The 2-, 5-, and 10-year survivorship of THA in patients with dwarfism was 92.9%, 92.9%, and 80.7%, respectively; and 94.4%, 86.4%, and 86.4% for controls, respectively (p = 0.95). The dwarfism cohort demonstrated an OR of 3.81 and 3.02 for revision for periprosthetic fractures (p = 0.11) and mechanical wear (p = 0.21), respectively.

CONCLUSIONS

THA in patients with dwarfism achieves comparable results to a non-dwarfism population with regards to implant survivorship; however, there is a trend toward increased periprosthetic fractures and wear-related failures. Surgeons should be aware of this potentially higher risk in this population and take morphological differences into account during surgical planning and technique.

Custom hemiarthroplasties for retention of existing hardware associated with osteogenesis imperfecta

Osteogenesis imperfecta is a rare genetic disorder that presents with heterogeneous phenotypes ranging from brittle bones to impaired hearing. Because of the decreased bone mineral density frequently observed in this patient population, many patients experience recurring and long-term fractures, which often require orthopaedic management. With the advancement of nonsurgical and surgical management and increased longevity of patients with osteogenesis imperfecta, the incidence of osteoarthritis has risen, presenting new orthopaedic challenges. However, compromised bone integrity and size combined with frequent existing hardware render traditional surgical therapies for osteoarthritis technically challenging in this patient population. In this report, we present a case in which we retained a portion of the patient's existing hardware, while performing staged bilateral custom hemiarthroplasties in a patient with osteogenesis imperfecta.

Cementless hip implants: an expanding choice

INTRODUCTION

Total hip replacement is a successful procedure with long survival records compared to other joint arthroplasties. Cemented implants have been available for many years, however the complications associated with loosening and, ultimately, failure over time has led to the development of cementless stems and implants.The ideal prosthesis should recreate a biomechanically normal hip joint, allow pain-free function and last the patient's life span without requiring revision. Optimal results with uncemented femoral stems rely on obtaining initial stability, osseointegration, biological fixation, and uniform stress transfer to the proximal bone.There are a multitude of factors that can affect the integration, stability and fixation of these stems into bone, and understanding these factors is the key to choosing the appropriate implant for a specific femur.

METHODS

This article aims to discuss cementless prostheses based on evidence-based practice. Geometry, roughness, stem coating, technique and bone quality are among the factors discussed. This was achieved through a review of the current literature.

CONCLUSIONS

Uncemented femoral stems have shown good, long-term survivorship and functional outcome, with promising results in younger patients.Limitations in the current literature make it difficult to assess and compare different designs to determine optimal indications for each type.Biological fixation, in which the prosthesis is directly fixed to the bone, is the preferred fixation method.Future studies of cementless implants should consistently address patient age, activity level, bone type, and deformities so that more definitive conclusions can be drawn about when to use each design.

The Wagner Cone Stem for the Management of the Challenging Femur in Primary Hip Arthroplasty

BACKGROUND

Splined conical stems offer design features that facilitate their use in the misshapen, dysplastic proximal femur.

METHODS

This study assessed the survivorship of a conical prosthesis when applied to secondary coxarthrosis because of a range of pathologies. Fifty-one prostheses were implanted in 50 patients with a mean age of 50 (range, 15-80) and a median follow-up of 34 months (range, 24-73 months). Indications for the stem included developmental (36), neuromuscular (7), post-traumatic or surgical (7), and inflammatory conditions (1). Survivorship, functional outcome (WOMAC [Western Ontaria and McMaster University Osteoarthrits Index], Oxford Hip Score, and UCLA [University of California Los Angeles]), health status (short form-12 [SF-12]), satisfaction, and osseointegration were determined.

RESULTS

Survivorship for aseptic loosening was 100% at 2 years and 98.04% for septic revision. Eight patients required reoperation, 4 for instability, and 1 each for infection, impingement, adverse reaction to metal debris, and pelvic insufficiency fracture. The mean WOMAC score was 85 (standard deviation [SD], 18), the mean Oxford Hip Score 84 (SD, 18), the mean physical SF-12 score was 48.3 (SD, 8.6), and the mean mental SF-12 was 53.7 (SD, 9.2), the mean satisfaction score was 91.5 (SD, 3.9), and the mean UCLA was 6 (SD, 1.6). All femoral components demonstrated osseointegration.

CONCLUSION

The cone femoral prosthesis demonstrates excellent early survival and osseointegration when applied to the challenging femur. Because of these encouraging results, we recommend this prosthesis be considered for the small, abnormal femur in primary hip arthroplasty.

Study of three-dimensional morphology of the proximal femur in developmental adult dysplasia of the hip suggests that the on-shelf modular prosthesis may not be an ideal choice for patients with Crowe type IV hips

PURPOSE

The purpose of this study was to investigate the three-dimensional morphological features of the proximal femur of developmental dysplasia of the hip (DDH).

METHODS

From January 2012 to December 2014, 38 patients (47 hips) of DDH were admitted and 30 normal hips were selected as controls. All hips from both groups were examined by CT scan. CT data were imported into Mimics 17.0. Three-dimensional models of the proximal femur were then reconstructed, and the following parameters were measured: neck-shaft angle, neck length, offset, height of the centre of femoral head, level of isthmus, height of the tip of greater trochanter, the medullary canal diameter of isthmus(Di), the medullary canal diameter 10 mm above the apex of the lesser trochanter(DT + 10), the medullary canal diameter 20 mm below the apex of the lesser trochanter(DT-20), and then DT + 10/Di, DT-20/Di and DT + 10/DT-20 were calculated.

RESULTS

There was no significant difference in neck-shaft angle between Crowe I, Crowe II-III DDH and the control group, while the neck-shaft angle was much smaller in Crowe IV DDH. The neck length of Crowe IV DDH was also much smaller than those of Crowe I and Crowe II-III DDH. Height of the tip greater trochanter in Crowe IV was greater than that in Crowe I, Crowe II-III DDH and the control group. The centre of femoral head in Crowe IV DDH was lower than those in Crowe I, Crowe II-III DDH and the control group. The level of isthmus in Crowe IV was much higher than those in Crowe I, Crowe II-III DDH and the control group. DT + 10, DT-20, DT + 10/Di and DT-20/Di were much smaller in Crowe IV DDH than those in Crowe I, Crowe II-III and the control group.

CONCLUSIONS

Neck-shaft angle in the DDH groups was not larger than that in the control group. Comparing to Crowe I, Crowe II-III DDH and the control group, Crowe IV DDH had a dramatic change in the intramedullary and extramedullary parameters, especially the dramatic narrowing of medullary canal around the level of the lesser trochanter. The on-shelf modular prosthesis may not be an ideal choice for the Chinese patients with Crowe IV hips.

Total Hip Arthroplasty in Patients with Skeletal Dysplasia

127 patients with a height ≤ 150 cm (non metric ≤ 4 feet and 11 inches) who received hip arthroplasty surgery between July 1, 2006 and May 30, 2013 at our institution were enrolled. Retrospective data evaluation was performed for two different times of follow-up (1 year and 5 years respectively). 115 patients were evaluated for 1-year follow up. Out of these, 27 patients were available for 5-year follow up. The mean Harris Hip Score increased from 40 ± 13 on admission to 82 ± 20 (P<0.001) at 1-year follow-up and 79 ± 17 (P<0.001) at 5-year follow-up. Hip arthroplasty can be performed in patients with dwarfism with good clinical benefits. However, survival rates are worse compared to the general population.

Total knee arthroplasty in patients with skeletal dysplasia

INTRODUCTION

Dwarfism is a challenge in arthroplasty. The anatomical features provide a lot of pitfalls. The aim of this study was to follow-up growth-restricted patients after endoprosthetic treatment.

MATERIALS AND METHODS

138 knee arthroplasties in patients with a height ≤150 cm between January 1, 2000 and May 5, 2013 at our institution were enrolled in this study. 124 cases were available for 1-year follow-up. Out of these, 43 cases were available for 5-year follow-up so far. 14 patients were lost to follow-up.

RESULTS

IKS score increased from 35 ± 16 on admission to 67 ± 22 (p < 0.001) at 1-year follow-up and 65 ± 23 (p < 0.001) at 5-year follow-up. Function Score increased from 40 ± 29 on admission to 64 ± 21 (p < 0.001) at 1-year follow-up and 63 ± 23 (p < 0.001) at 5-year follow-up. Revision surgery was required in one case (0.8 %) after 1-year follow-up, and in an additional three cases (7 %) after 5-year follow-up.

CONCLUSIONS

Knee arthroplasty can be performed in patients suffering from dwarfism with good clinical benefits. However, survival rates are worse compared to the general population.

[Ipsilateral THA after stemmed TKA: Risk of interprosthetic fracture?]

BACKGROUND

There is an increasing number of patients who have undergone stemmed total knee arthroplasty and total hip arthroplasty in the same leg. These patients may be at increased risk of periprosthetic and interprostethic fracture. Etiology and the potential therapy strategies are not well represented in the current literature.

OBJECTIVES

Determination of the risk factors for interprosthetic fractures and possible prevention.

MATERIALS AND METHODS

We performed a review of the literature and additionally a survey among experts (members of the German Association for Arthroplasty [AE]) to investigate the risk and the necessity for a preventive internal fixation.

RESULTS

There are only a few biomechanical studies. The interprosthetic distance seems to have little influence on the fracture risk, but the thickness of the cortex and the cortical area at the diaphysis seems to be important. The value of a bridging osteosynthesis remains uncertain. Ninety experts took part in the survey. The risk of fracture risk was estimated to be only slight to medium. Opinions regarding the necessity of preventive internal fixation were heterogeneous.

CONCLUSIONS

The indication for preventive internal fixation could be derived neither from the literature nor from the survey of experts. The thickness of the cortex and co-morbidities (osteoporosis, tendency to fall, and medication) seem to be more important than the interprosthetic distance.

Outcome of custom-made IMP femoral components of total hip arthroplasty: a follow-up of 15 to 22 years

A total of 1659 primary THAs using a cemented custom-made intra-operative manufactured prosthesis (IMP)-stem were studied. The end point for survival was defined as revision of the stem for any reason. Revision arthroplasty was performed in 49 cases. The IMP-stems had a revision free 20-year survival rate of 95.5%. Revisions were performed mainly because of aseptic loosening. There were no drawbacks like increased infection risk due to the prolonged surgical time needed for the intra-operative production of the stem. These data provide evidence that the cemented IMP-stem is able to provide good long-term results.

The ratio of femoral head diameter to pelvic height in the normal hips of a Chinese population

OBJECTIVE

The aim of this study was to determine whether the ratio between the femoral head diameter and pelvic height in a Chinese population is the same as that found in Westerners.

MATERIALS AND METHODS

Standard pelvic radiography was performed on a group of 187 Chinese adult subjects consisting of 81 males and 106 females with a mean age of 40 years (21-68 years). Femoral head diameter (vertical distance from the femoral head-neck junction to the highest point of the femoral head) and pelvic height (vertical distance from the highest point of the iliac crest to the edge of the ischial tuberosities) were measured.

RESULTS

There were significant differences between males and females (p < 0.001), and between persons of high height versus low height (p = 0.011) and medium height (p = 0.039). There were no significant differences between persons of different age (p = 0.244), body mass index (p = 0.091), or between persons of low- and medium-height groups (p = 0.69). The overall mean ratio between the femoral head diameter and pelvic height was 0.215 (0.173-0.249) with a 95 % CI = 0.214-0.217. The mean ratios in males and females were 0.221 (0.194-0.249) and 0.211 (0.173-0.238), respectively.

CONCLUSION

The mean ratio in Chinese population was similar to the reported ratio in a western population (about 1:5). We suggest that Chinese surgeons may be able to use the Crowe classification to classify patients with hip dysplasia.