Is Modular Prosthesis Superior to Monoblock Variant in Hemiarthroplasty for Fracture Neck of Femur?

Background

The incidence of hip fractures is increasing every year worldwide. Even though hemiarthroplasty is one of the most common procedures performed for a fractured neck of the femur, there is very little research comparing the outcomes of monoblock and modular systems, the two most commonly used prostheses in neck of the femur fractures. It was hypothesized that in narrow femoral canals, the single-size monoblock stem would be more difficult to insert and lead to complications like limb lengthening and intra-operative calcar fractures. The objective of our study was to compare the outcomes of a modular prosthesis with that of a monoblock prosthesis in a fractured neck of the femur.

Materials and Methods

This study analyzed the surgical outcomes of 192 cases of hemiarthroplasties performed over a 4-year period using a modular system and compared it to 192 cases performed using a single-sized monoblock system.

Results

The monoblock systems were more likely to cause post-operative limb lengthening compared to their modular counterparts (P = 0.01). The incidence of intra-operative fractures was also more in the monoblock system, although it was not statistically significant. Up to 45% of patients required a femoral stem size smaller than the single-sized monoblock system as the optimum size for their femoral canals, which was available only in the modular system.

Conclusions

Modular prosthesis was found to have lower chances of post-operative limb lengthening and lower chances of intraoperative calcar fractures compared to monoblock prosthesis. Careful pre-operative radiologic planning is essential in cases where monoblock systems are used, and the modular system might serve as a viable solution in such scenarios.

Hip offset and leg-length restoration in revision hip arthroplasty with a monoblock, hydroxyapatite-coated stem

AIMS

Restoration of normal hip biomechanics in arthroplasty surgery is important in order to achieve good muscle function and joint stability.

METHODS

In this retrospective cohort study, we examined the postoperative radiographs of 131 femoral revision arthroplasty procedures using a monoblock, fully hydroxyapatite (HA)-coated titanium stem. Femoral offset, modified-global offset and leg length were measured of the operated and contralateral hips.

RESULTS

Femoral offset was restored to ±10 mm in 108 cases (82%), modified-global offset was restored ±10 mm in 93 cases (71%) and leg length was restored to ±10 mm in 102 cases (81%). There were 4 dislocations with a mean follow-up period of 38 months.

CONCLUSIONS

Restoration of hip biomechanics is achievable with a monoblock stem and thus is a viable option in revision hip arthroplasty.

The 45-year evolution of the Mathys RM monoblock cups: have the paradigm shifts been worthwhile?

INTRODUCTION

The Robert Mathys (RM) monoblock uncemented cup is a design less commonly used in primary total hip replacement. It's purported advantages over modular cemented cups are: (1) its modulus of elasticity approximating bone, thus mimicking load transmission and the biomechanical behaviour of the cup to better match stresses on the acetabulum, leading to bone-preservation; and (2) as a 1-piece cup there is absence of a mobile interface between a liner and shell, preventing backside wear. Since its inception in 1983 there have been 3 major design changes: the RM Classic, the RM Pressfit, and the RM Vitamys with the most modern polyethylene (vitamin E).

METHODS

In a retrospective cohort study of the New Zealand Joint Registry, all designs of RM acetabular cup were reviewed. Data were included from1998 to 2018. All-cause revision rates, reasons for revision and the Oxford Hip Score (OHS) were assessed.

RESULTS

In total 13,272 acetabular cups were included. The all-cause revision rates did not differ between the designs. Revision rates for aseptic loosening in the RM Vitamys were lower, but the follow-up was shorter and more larger heads were used. There was no difference in the OHS.

CONCLUSION

All implant designs were safe. The use of larger heads led to a decrease in revisions due to dislocation. It has to be waited out whether the RM Vitamys performs superior in the long-term due to the highly cross-linked polyethylene.

Use of a monoblock dual-mobility acetabular component in primary total hip arthroplasty in patients at high risk of dislocation

INTRODUCTION

Dislocation is amongst the most common complications following total hip arthroplasty (THA). Dual-mobility bearings have been suggested as one way to reduce the risk of dislocation, particularly among patients at increased risk. The purpose of this study was to determine the outcomes of a monoblock dual-mobility shell for patients at high risk for dislocation following primary THA.

METHODS

A total of 155 primary THAs with a monoblock, cementless dual-mobility acetabular component were performed in patients at high risk for dislocation. Two patients died prior to their two-year follow-up. The remaining 153 THAs were followed for a mean of 5.1 years (range: 2.1 to 9.3).

RESULTS

There were no dislocations; however, four patients underwent revision surgery: one for an early periprosthetic acetabular fracture, one for an early periprosthetic femoral fracture, one for a late periprosthetic femoral fracture, and one for leg-length discrepancy. Intraoperative complications included one periprosthetic acetabular fracture treated with protected weight-bearing and one intraoperative proximal femoral fracture treated with cerclage wiring. Harris Hip Scores improved from a mean of 42.4 points preoperatively to a mean of 82.4 points postoperatively (p < 0.001). No cups were radiographically loose. At a mean follow-up of 5.1 years, survivorship of the acetabular component was 99.3% (95% CI, 98.1-100%) and survivorship without any reoperation was 97.4% (95% CI, 95.9-100%).

DISCUSSION

Although there were no dislocations in this high-risk population, periprosthetic fractures of the femur and acetabulum were common with the implants utilised.

The Effect of Femoral Head Size on Groin Pain in Total Hip Arthroplasty

BACKGROUND

Although increased femoral head size reduces the risk of instability in total hip arthroplasty (THA), it may lead to iliopsoas irritation and increased anterior groin pain. The purpose of this study is to compare outcomes between non-modular dual-mobility (NDM) implants and small (≤32 mm) and large (≥36 mm) fixed-bearing (FB) constructs.

METHODS

A retrospective review of all primary total hip arthroplasties from 2011 to 2021 was conducted at a single, urban academic institution. Patients were separated into 3 cohorts: NDM implant ≤32 mm and FB implant ≥36 mm. Demographics and outcomes such as length of stay, dislocation, and anterior groin pain were assessed. Patients were deemed as having groin pain if they received an iliopsoas injection or had extended physical therapy ordered beyond 3 months postoperatively.

RESULTS

There were 178 NDM implants, 936 ≤32-mm FB, and 2,454 ≥36-mm FB implants included. Length of stay significantly differed between the groups (48.4 ± 43.3 vs 63.2 ± 40.6 vs 57.2 ± 38.1 hours; P = .001). Although not statistically significant, the ≥36-mm FB cohort had the highest rate of dislocations (0.6% vs 0.7% vs 0.9%; P = .84). Although no patients with an NDM implant received an iliopsoas injection, 9 patients (0.9%) with a ≤32-mm FB implant and 9 patients (0.4%) with a ≥36-mm implant received an injection (P = .06). However, 18 (10.1%) patients with an NDM implant, 304 (32.5%) patients with a ≤32-mm FB implant, and 355 (14.5%) patients with a ≥36-mm FB implant received extended physical therapy 3 months after surgery (P < .001).

CONCLUSION

NDM implants, as well as FB implants with both small and large head sizes are effective at preventing dislocation. NDM implants did not result in an increase in anterior groin pain compared to ≤32-mm and ≥36-mm FB constructs.

LEVEL III EVIDENCE

Retrospective cohort study.

Survival of monoblock RM vitamys compared with modular PINNACLE cups: mid-term outcomes of 200 hips performed by a single surgeon

INTRODUCTION

Monoblock cups have theoretical advantages over modular cups; however, their superiority in terms of survival has not been confirmed in comparative studies.

METHODS

We compared the mid-term survivorship of 107 RM Pressfit vitamys monoblock cups (Mathys Ltd., Bettlach, Switzerland) with 93 modular pressfit Pinnacle cups (DePuy Synthes, Warsaw, IN, USA). All cases were registered in the Arthroplasty Registry Thessaloniki and performed by a senior surgeon through the same approach between 2013 and 2014. The groups were comparable in sex distribution, preoperative diagnosis, follow-up, cup diameter, head diameter, type and use of screws, HOOS and HSS preop scores; the recipients of RM cup were significantly younger.

RESULTS

3 sockets were revised. The 6-year survival for any reason was 99.1% for the RM and 97.8 % for the PINNACLE group. There was no difference in survival for aseptic loosening and any reason between groups (log-rank test p = 0.921 and p = 0.483, respectively). The age (95% CI, 0.79-1.1), sex (95% CI, 0.2-45.0), cup diameter (95% CI, 0.18-1.1), head diameter (95% CI, 0.004-6.2), preoperative diagnosis and use of screws (95% CI, 0.02-4.3), did not influence hazard ratio for revision between groups. HHS and HOOS were comparable at the last follow-up.

CONCLUSIONS

Our study demonstrated that both cup designs had similar revision rates at mid-term follow-up, regardless the fact that the RM vitamys was used in a cohort of younger patients; which according to the literature would have led to earlier failures. Further long-term data are needed to evaluate the superiority of RM vitamys in the clinical setting, especially in the young.

A cohort comparison of humeral implant designs in reverse shoulder arthroplasty: does implant design lead to lower rates of complications and revision?

INTRODUCTION

The purpose of this study was to evaluate the outcomes, revisions, and complications between a first-generation cemented modular humeral implant and a second-generation monolithic, primarily uncemented humeral implant in reverse total shoulder arthroplasty with 135° neck-shaft angle and varying degrees of metallic glenosphere offsets.

METHODS

We retrospectively evaluated patients undergoing reverse total shoulder arthroplasty from 2004 to 2014 with a first-generation cemented modular humeral implant (400 patients) or second-generation monolithic humeral stem (231 patients), who had at minimum 2-year clinical and radiographic follow-up.

RESULTS

Both groups of patients had similar improvement of clinical outcomes (American Shoulder and Elbow Surgeons +30 points vs. +34 points, respectively) with improvements in all planes of motion (forward flexion +70° vs. +75°, abduction +61° vs. +71°, external rotation +23° vs. +22°, and internal rotation +1.6 vs. +1.5 level improvement, respectively). The incidence of humeral loosening for the cemented group was 3.6%, whereas in the uncemented group it was 0.4% (P = .01). A total of 28 shoulders treated with the cementing technique (4.0%) and 6 patients treated with the press-fit technique (1.5%) were revised (P = .028). The rate of postoperative acromial fractures within the first year was 3.4% in the cemented group and 1.8% in the uncemented group (P = .177).

CONCLUSIONS

Both the first-generation cemented modular humeral stem implant and the second-generation monolithic humeral stem implant had equivalent clinical outcomes. In addition, with the monolithic stem primarily using press-fit fixation, there was a significant reduction in the incidence of radiographic loosening and the need for revision compared with a cemented stem.

Long-Term Results of Revision Total Hip Arthroplasty Using a Modern Extensively Porous-Coated Femoral Stem

BACKGROUND

The use of an extensively porous-coated uncemented cobalt-chrome monoblock femoral stem for revision total hip arthroplasty (THA) is well established with excellent mid-term results. The aim of this study is to report the long-term survivorship of these implants in femoral stem revisions.

METHODS

This is a long-term retrospective review of prospectively collected data of 55 femoral stem revisions in 55 patients using a contemporary, cementless extensively porous-coated cobalt-chrome monoblock stem. All patients between 2001 and 2006 who underwent first time femoral stem revision with a contemporary, cementless extensively porous-coated cobalt-chrome monoblock stem were included. Harris Hip Score, Western Ontario and McMaster Universities Index, and University of California Los Angeles activity scores were recorded preoperatively and at latest follow-up. Radiographs were analyzed for evidence of loosening, subsidence, osteolysis, and bony union. This study included 55 patients, comprising of 36 females (66%) and 19 males (34%) with a mean age of 66.4 ± 9.3 years at the time of surgery. The mean time interval from index procedure was 9.8 ± 2.9 years. Mean time from revision THA to final follow-up was 13.2 ± 2.17 years with a minimum of 10 years of follow-up.

RESULTS

Indications for revision included aseptic loosening (33), prosthetic joint infection (13), and periprosthetic fracture (10). Significant improvement in Harris Hip Score (85.1 ± 1.77 vs 51.8 ± 2.3, P < .001), Western Ontario and McMaster Universities Index (17.6 ± 0.77 vs 33.3 ± 0.8, P < .001), and University of California Los Angeles (5.25 ± 0.2 vs 2.7 ± 0.36, P < .001) scores were found at latest follow-up compared to preoperative. Fifty-four patients (98%) achieved stable bony ingrowth on radiographic analysis. All 10 patients treated for periprosthetic fractures achieved bony union of their fractures. Two patients suffered intraoperative periprosthetic fractures and were treated with a cable-plating system. There were no mechanical failures and no femoral stem re-revisions. One patient was diagnosed with a deep infection and was treated with chronic suppressive antibiotic therapy due to significant medical comorbidities.

CONCLUSION

Revision of the femoral component with a contemporary extensively porous-coated cobalt-chrome femoral stem has excellent functional outcomes, radiographic outcomes, and long-term survivorship with minimal complications.

Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite-Coated Titanium Stem in Revision Hip Arthroplasty

BACKGROUND

We evaluated the survivorship, incidence of complications, radiological subsidence, proximal stress shielding, and patient-reported outcomes of a conservative, monoblock, hydroxyapatite-coated femoral stem.

METHODS

This retrospective cohort study reports on 254 revision hip arthroplasties between January 2006 and June 2016. The mean age of patients was 71 years. The mean length of follow-up was 62 months (range 12-152).

RESULTS

There were 13 stem re-revisions: infection (4), periprosthetic fracture (4), aseptic stem loosening (3), stem fracture (1), and extended trochanteric osteotomy nonunion (1). Kaplan-Meier aseptic stem survivorship was 97.33% (confidence interval 94-100) at 6 years. There were 29 intraoperative fractures. There were 6 cases of subsidence greater than 10 mm; however, none required revision. Ninety-six percent of cases showed no proximal stress shielding. Thigh pain was reported in 3% of cases.

CONCLUSION

This study confirms that this stem provides good survivorship at 6 years, acceptable complication rates, adequate proximal bone loading, low incidences of thigh pain, and reliable clinical performance in revision hip arthroplasty.

KEY MESSAGE

A monoblock, fully hydroxyapatite-coated titanium stem is reliable in revision arthroplasty with mild-moderate femur deficiencies.

The Morscher Press-Fit Acetabular Component: An Independent Long-Term Review at 18-22 Years

BACKGROUND

There are relatively few 20-year results of uncemented acetabular components, and most of these are modular designs. This study reports the 20-year results of a monoblock press-fit acetabular component.

METHODS

A total of 122 total hip arthroplasties (111 patients) using the Morscher cup were reviewed at a mean of 19.7 years. The average age at implantation was 57.3 years (range, 36-74 years), and 81 (66%) were men.

RESULTS

Twenty-two patients (25 hips) had died. Seven hips were revised, including 5 acetabular revisions. Six patients (6 hips) declined to participate but were known not to have been revised. The mean Oxford hip score was 41.1 (range, 22-48), and the mean reduced Western Ontario and McMaster Universities Osteoarthritis Index score was 5.7/48 (range, 0-24). Eccentric wear was seen in 13 (15.7%) and major osteolysis in 14 (17%) of 82 surviving hips with radiographs. The all-cause revision rate was 0.32 per 100 observed component years (95% confidence interval [CI], 0.13-0.66). The 20-year Kaplan-Meier survival was 93.4% (CI, 86.6-96.8) for all-cause revisions, 95.5% (CI, 89.4-98.1) for any acetabular revision, and 97.1% (CI, 91.2-99.1) for acetabular aseptic loosening, wear, or osteolysis.

CONCLUSION

The Morscher acetabular component has continued to perform well at 20 years despite using conventional polyethylene with results that match or surpass other cementless acetabulae.

Biological post

Anterior tooth fracture as a result of traumatic injuries, is frequently encountered in endodontic practice. Proper reconstruction of extensively damaged teeth can be achieved through the fragment reattachment procedure known as “biological restoration.” This case report refers to the esthetics and functional recovery of extensively damaged maxillary central incisor through the preparation and adhesive cementation of “biological post” in a young patient. Biological post obtained through extracted teeth from another individual–represent a low-cost option and alternative technique for the morphofunctional recovery of extensively damaged anterior teeth.

Epiphany sealer penetration into dentinal tubules: Confocal laser scanning microscopic study

AIMS

The aim of the following study was to evaluate the percentage and average depth of epiphany sealer penetration into dentinal tubules among the coronal, middle and apical thirds of the root using the confocal laser scanning microscopy (CLSM).

MATERIALS AND METHODS

A total of 10 maxillary central incisors were prepared and obturated with Resilon-Epiphany system. Sealer was mixed with fluorescent rhodamine B isothiyocyanate dye for visibility under confocal microscope. Teeth were cross-sectioned into coronal, middle and apical sections-2 mm thick. Sections were observed under CLSM. Images were analyzed for percentage and average depth of sealer penetration into dentinal tubules using the lasso tool in Adobe Photoshop CS3 (Adobe systems incorporated, San jose, CA) and laser scanning microscopy (LSM 5) image analyzer.

STATISTICAL ANALYSIS USED

One-way analysis of variance with Student Neuman Keuls post hoc tests, Kruskal-Wallis test and Wilcoxon signed-rank post hoc tests.

RESULTS

The results showed that a higher percentage of sealer penetration in coronal section-89.23%, followed by middle section-84.19% and the apical section-64.9%. Average depth of sealer penetration for coronal section was 526.02 μm, middle-385.26 μm and apical-193.49 μm.

CONCLUSIONS

Study concluded that there was higher epiphany sealer penetration seen in coronal followed by middle and least at apical third of the roots.