Comparing the long-term results of two uncemented femoral stems for total hip arthroplasty

A Study of Tibial Cyst Formation in Modular Stemmed Total Ankle Arthroplasty: Exploring a Possible Relationship to Smooth and Porous Coating on the Stem Segments

Vertical fixation through stemmed components has been a successful strategy in total ankle arthroplasty. Research in hip replacement surgery has demonstrated increased rates of stress shielding, aseptic loosening, thigh pain, and cystic formation around stemmed femoral implants extensively coated with porous surfaces. While some ankle prostheses have integrated porous coating technology with stemmed tibial implants, there is little to no research investigating the potential negative effects of bone bonding to the tibial stems and possible impact on tibial cyst formation. We performed a retrospective cohort study comparing the incidence of periprosthetic tibial cyst formation in smooth versus fully porous-coated stemmed tibial implants after undergoing total ankle implant arthroplasty. Radiographs were compared for postoperative rates of tibial cyst formation and bone bonding to the tibial stems. Relative risk for reoperation between the smooth and porous-coated implants was investigated. The smooth-stem group showed no incidence of tibial cyst formation nor signs of significant bone bonding to the tibial stems; however, the follow-up matched porous-coated group showed a rate of 63% of cystic formation with associated evidence of bone bonding on final radiographic follow-up (p < .01). Relative risk for reoperation was 0.74. Despite a higher incidence of tibial cyst formation in the stemmed ankle arthroplasty groups with porous coating, reoperation rates were similar. We theorize that the proximal bonding to the porous stem surface could impact the distal stems and result in the observed increase in cyst formation.

Intermediate to Long-Term Outcomes and Causes of Aseptic Failure of an At-Risk Femoral Stem

BACKGROUND

The Accolade TMZF is a tapered-wedge cementless metaphyseal-coated femoral stem that was widely utilized from 2002 to 2012. In recent years, there have been reports of early catastrophic failure of this implant. The purposes of the present study were to establish the long-term survival of this stem and to analyze patients who underwent aseptic revision to understand the causes and risk factors for failure.

METHODS

We retrospectively reviewed the records of all patients who had undergone primary total hip arthroplasty with use of an Accolade TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented. Survivorship analysis was performed with use of Kaplan-Meier curves to determine the overall and aseptic survival rates at the time of the latest follow-up. Patient and implant factors commonly associated with aseptic failure were extracted, and a Cox proportional hazards model was used.

RESULTS

A consecutive series of 2,609 patients who had undergone unilateral primary total hip arthroplasty with use of an Accolade TMZF femoral stem were included. The mean time from the primary procedure was 11.3 years (range, 0 days to 19.4 years). The cumulative survival rate was 95.5% ± 0.1% at the time of the latest follow-up. One hundred and seven patients underwent revision surgery, with aseptic loosening of the femoral component being the most common cause of aseptic failure in this cohort (33 of 2,609; 1.3%). Smaller femoral size and larger femoral head offset were independent risk factors for aseptic failure.

CONCLUSIONS

To our knowledge, this is the largest series representing the longest follow-up of this tapered-wedge cementless femoral implant. Despite early concerns, the Accolade TMZF stem had excellent survivorship in this cohort. Trunnionosis as the cause for revision surgery was rare.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-Term Outcomes of 496 Anatomical Cementless Modular Femoral Stems: Eleven to Twenty Years of Follow-Up

BACKGROUND

The aim of the study is to assess the long-term outcomes of this specific stem (anatomical cementless modular stem ESOP), to review the survivorship, complication rate, and radiographic and clinical outcomes.

METHODS

Descriptive and analytical retrospective longitudinal observational study of patients was operated on total hip arthroplasty between 1998 and 2007. Four hundred ninety-six prostheses corresponding to 447 patients were reviewed, mean age was 65.8 years (standard deviation [SD] ±11.6 years), and median follow-up time was 13.4 years (range 1-20). The most used cups were cementless (75.8%). The most frequent friction pairs were metal-polyethylene (53.1%) and ceramic-polyethylene (24.2%). Main variables analyzed were stem survival, subsidence, coronal orientation, osteolysis, reintervention, and Oxford Hip Score.

RESULTS

From 496 implants, there were 22 lost to follow-up (4.4%). Stem revision was performed in 51 patients: 26 periprosthetic joint infections (2-stage revision), 16 periprosthetic fractures, and 8 one-stage revisions (6 real aseptic loosening with negative culture after revision). The stem survivorship at more than 15 years for any reason was 89.2% and for aseptic loosening 97.97%. No specific complications were found due to modularity. The mean subsidence and orientation was 2.06 mm (SD ±5.11 mm) and 0.41° varus (SD ±2.20°) respectively. Subsidence >5 mm or varus >5° was associated with a higher revision rate. Osteolysis was found in 110 patients (zone I = 79, VII = 57), associated with zirconium-polyethylene, without relationship to the stem revision rate or Oxford Hip Score.

CONCLUSION

To our knowledge, this study represents the largest series of this stem, revealing an excellent survival rate and long-term clinical outcomes similar to the best results of classical cementless stems published in the literature.

Long Term Performance of an Uncemented, Proximally Hydroxyapatite Coated, Double Tapered, Titanium-Alloy Femoral Stem: Results From 1465 Hips at 10 years Minimum Follow-Up

BACKGROUND

We assessed the survivorship of a proximally hydroxyapatite coated, double tapered, titanium-alloy femoral stem in a single center, at an average follow up of 12.5 years (10.1-15.8). The majority of stems were inserted as part of a Metal on Metal (MoM) Total Hip Replacement (THR).

METHODS

Data was collected prospectively in a local database. A retrospective review was performed of all patients undergoing a primary THR with the prosthesis between 2003 and 2010. Primary outcome was revision of the stem for any cause. Analysis was also performed for stem revision for aseptic loosening, stem revision in the MoM setting and a worst case scenario whereby lost to follow up were presumed to have failed. True stem failure was considered if revision occurred for a stem related complication.

RESULTS

1465 stems were included (1310 patients, 155 bilateral). The bearing surface was cobalt chrome on cobalt chrome in 1351 cases (92%). Seven hips were lost to follow up. Thirty-two stems (31 part of a MoM THR) underwent revision for any cause. Kaplan Meier survival analysis demonstrates an overall 97.4% survivorship. Subset analysis demonstrates 100% survivorship for aseptic loosening, 97.3% in the MoM setting and 96.7% for the worst case senario. Of the 32 cases of stem revision, only 13 were classified as 'true' stem failure.

CONCLUSION

This study represents the largest cohort of this uncemented femoral component with a minimum follow-up longer than 10 years. Our results demonstrate excellent long-term survivorship even in the presence of a challenging MoM environment.

Biomechanical Analysis to Probe Role of Bone Condition and Subject Weight in Stiffness Customization of Femoral Stem for Improved Periprosthetic Biomechanical Response

Stress shielding due to difference in stiffness of bone and implant material is one among the foremost causes of loosening and failure of load-bearing implants. Thus far, femoral geometry has been given priority for the customization of total hip joint replacement (THR) implant design. This study, for the first time, demonstrates the key role of bone condition and subject-weight on the customization of stiffness and design of the femoral stem. In particular, internal hollowness was incorporated to reduce the implant stiffness and such designed structure has been customized based on subject parameters, including bone condition and bodyweight. The primary aim was to tailor these parameters to achieve close to natural strain distribution at periprosthetic bone and to reduce interfacial bone loss over time. The maintenance of interfacial bone density over time has been studied here through analysis of bone remodeling (BR). For normal bodyweight, the highest hollowness exhibited clinically relevant biomechanical response, for all bone conditions. However, for heavier subjects, consideration of bone quality was found to be essential as higher hollowness induced bone failure in weaker bones and implant failure in stronger bones. Moreover, for stronger bone, thinner medial wall was found to reduce bone resorption over time on the proximo-lateral zone of stress shielding, while lateral thinning was found advantageous for weaker bones. The findings of this study are likely to facilitate designing of femoral stems for achieving better physiological outcomes and enhancement of the quality of life of patients undergoing THR surgery.

Cemented versus uncemented total hip replacement for femoral neck fractures in elderly patients: a retrospective, multicentre study with a mean 5-year follow-up

Background

Cemented or uncemented total hip replacement (CTR or UTR) for femoral neck fractures (AO/OTA type 31B/C) is a relatively common procedure in elderly individuals. The recent literature is limited regarding long-term outcomes following CTR versus UTR in the Asian population.

Methods

Using our institutional database, we performed long-term outcome analysis on 268 patients with femoral neck fractures (AO/OTA type 31B/C) who had undergone a primary UTR or CTR (CTR: n = 132, mean age, 67.43 ± 6.51 years; UTR: n = 136, mean age, 67.65 ± 6.13 years) during 2007–2014, and these patients were followed until 2019. Follow-up occurred 1, 3, 6, and 12 months postoperatively and yearly thereafter. The primary endpoint was the Harris hip score (HHS); the secondary endpoint was the incidence of orthopaedic complications.

Results

The mean follow-up time was 62.5 months (range, 50.1–76.1 months). At the final follow-up, the HHS was 79.39 ± 16.92 vs 74.18 ± 17.55 (CTR vs UTR, respectively, p = 0.011). Between-group significant differences were observed regarding the incidence of prosthesis revision, prosthesis loosening, and periprosthetic fracture (7.6% [95% CI, 6.4–8.2] for CTR vs 16.9% [95% CI, 14.7–17.3] for UTR, p = 0.020; 9.8% [95% CI, 8.3–10.7] for CTR vs 19.9% [95% CI, 18.2–20.9] for UTR, p = 0.022; 5.3% [95% CI, 4.4–6.7] for CTR vs 13.2% [95% CI, 12.1–13.8] for UTR, p = 0.026, respectively).

Conclusion

CTR showed superiority to UTR by improving the HHS and decreasing the incidence of orthopaedic complications. Our findings need to be confirmed in a prospective, randomized controlled study to verify whether they can be applicable to a broader population.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BACKGROUND

This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.

METHODS

We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score.

RESULTS

Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.

CONCLUSION

This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

An excellent 5-year survival rate despite a high incidence of distal femoral cortical hypertrophy in a short hip stem

BACKGROUND

Although reported results on short stems sound very promising, the occurrence of distal femoral cortical hypertrophy is often observed. The aim of the present study was to report 5-year survival data of a commercially available trochanter sparing short stem and investigate the clinical impact of distal femoral cortical hypertrophy on the outcome.

METHODS

123 total hip arthroplasties were performed on 120 patients from April 2008 to May 2010 (mean age 62, range 29-89 years; 71 hips from male patients, 58%). Clinical and radiological data were collected preoperative, at 6 weeks, 1, 2, 3, and 5 years postoperative to assess the outcome. Radiographs taken immediately postoperative as well as 1 and 5 years postoperative were used to identify and assess cortical hypertrophy.

RESULTS

1 stem had to be revised due to aseptic loosening, resulting in a Kaplan-Meier survival analysis with endpoint for stem revision of 99.2% (95% Confidence Interval 94.1-99.9) at 5 years. 96 radiological and 95 clinical follow-ups were analysed 5 years postoperative. 68 (71%) hips showed distal femoral cortical hypertrophy after 5 years. The average Harris Hip Score and Oxford Hip Score improved 33 (standard deviation (SD) 15.1, range 2-70), 18 (SD 12.1, range -10-43) points, respectively. Overall 16% of the patients reported thigh pain, unrelated to the presence of cortical hypertrophy.

DISCUSSION

This short stem shows an excellent 5-year survival rate and good clinical outcome despite a high incidence of cortical hypertrophy. However, the question of the mechanism of load transfer arises.

Humeral Stem Loosening Following Reverse Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Aseptic stem loosening following reverse shoulder arthroplasty (RSA) is an uncommon complication. The timing and the factors contributing to aseptic stem loosening remain poorly understood.

METHODS

We performed a systematic review that identified 75 articles; 65 of the included articles were case series (Level-IV evidence), 8 were cohort studies (7 Level III, 1 Level II), and 2 were prospective randomized controlled trials (Level I). A meta-analysis of 1,660 cemented and 805 uncemented RSA stems was performed. We compared the rates of aseptic stem loosening, humeral radiolucent lines, and revision for stem loosening (1) between cemented and uncemented stems in cohorts with short and long mean follow-up periods (<5 and ≥5 years) as well as in all cohorts combined, and (2) among different etiological subgroups.

RESULTS

Aseptic stem loosening occurred more commonly in the cohort with long compared with short follow-up time (2% versus 0.8%, p = 0.01). When comparing cemented with uncemented stems, there was no significant difference in the rates of aseptic stem loosening or revision for stem loosening in either the short or long-term follow-up groups. Humeral radiolucent lines were more common with cemented compared with uncemented stems (15.9% versus 9.5%, p = 0.002). Analyzed by etiology, the highest rate of aseptic stem loosening occurred in the tumor subgroup (10.8%), followed by RSA as a revision procedure after a failed arthroplasty (3.7%). No stems in the acute fracture or fracture sequelae subgroups developed aseptic stem loosening.

CONCLUSIONS

Aseptic stem loosening occurred more commonly in cohorts with longer follow-up. There were no differences in the rates of aseptic stem loosening or revision for stem loosening between cemented and uncemented stems. Patients treated with RSA following excision of proximal humeral tumors and RSA as a revision procedure after a failed arthroplasty were at greater risk of aseptic stem loosening.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Arthroscopic Diagnosis and Treatment of Chronic Hip Pain After Total Hip Arthroplasty and the Role of Anterior Capsule Disruption in Iliopsoas Tendinopathy

Background:

The use of hip arthroscopic surgery in patients suffering from chronic hip pain after total hip arthroplasty (THA) has a limited presence in the literature, with most studies having limited follow-up.

Purpose:

The first goal of this study was to evaluate hip arthroscopic surgery in the diagnosis and management of patients with chronic hip pain after THA. The second goal was to describe a new cause of iliopsoas tendinopathy (IPT) involving disruption of the anterior capsule.

Study Design:

Case series; Level of evidence, 4.

Methods:

We conducted a retrospective analysis with prospectively collected clinical outcomes of patients after THA who underwent hip arthroscopic surgery for chronic hip pain without an identifiable cause. The patients were at least 18 years old and had a minimum follow-up of 24 months.

Results:

The retrospective analysis found that hip arthroscopic surgery led to new diagnostic information in 8 patients (80%). Of the 10 patients diagnosed with IPT, 4 (40%) lacked an anatomic cause; however, these patients had a history of difficult exposure of the anterior capsule and/or a lack of capsular repair during index THA. The mean modified Harris Hip Score (mHHS) was 71.9 ± 15.6, and the mean 6-month postoperative visual analog scale (VAS) pain score was 0.8 ± 2.2, which was significantly lower than preoperatively (P = .0055). There was also significantly improved forward flexion range of motion (P = .0183) and straight leg raise (SLR) strength test results (P = .0263). Hip arthroscopic surgery resulted in 8 patients (80%) continuing to be pain-free at a mean follow-up of 6.8 ± 1.4 years, while 2 patients (20%) progressed to revision arthroplasty. There were no major or minor complications.

Conclusion:

Hip arthroscopic surgery was found to have an important role in the diagnostic and therapeutic management of patients with chronic hip pain after THA, with good clinical outcomes at a mean follow-up of 6.8 years and no complications. We believe that disruption of the anterosuperior acetabular capsule, including the reflected head of the rectus femoris, can allow the iliopsoas tendon to move intra-articularly and precipitate IPT. This disruption may be appreciated on the SLR strength test. Although this study presents a small sample size that cannot substantiate a cause-effect relationship, orthopaedic surgeons performing THA should consider minimizing disruption and/or ensuring repair of the anterior capsule to decrease this potential cause of IPT.

A shortened uncemented stem offers comparable positioning and increased metaphyseal fill compared to a standard uncemented stem

BACKGROUND

Shortened stems are increasingly used in uncemented total hip arthroplasty (THA) as they represent a compromise between the metaphyseal anchorage of short stems and the facilitated axial alignment of standard stems. The purpose of this study was to compare the metaphyseal canal-fill ratio (CFR) and axial alignment of a shortened double-tapered stem with those of a standard stem. The hypothesis was that the shortened stem would achieve greater metaphyseal fill and comparable axial alignment.

METHODS

The authors reviewed routine follow-up anteroposterior radiographs taken 2 months after THA to evaluate metaphyseal fill and axial alignment of a shortened stem (n = 96) and a standard stem (n = 101). The CFR was calculated at the level of the tip and superior margin of the lesser trochanter. Stem alignment was defined as the angle between the stem axis and the proximal anatomic femoral axis. Stems were classified as being in varus or valgus alignment if they deviated by more than 3° from the anatomic axis of the femur.

RESULTS

Hips implanted with shortened and standard stems had comparable demographics and axial alignment (1.1° ± 1.7° vs 0.8° ± 1.2°; p = 0.331). However, varus alignment was observed in 5% of shortened stems compared to only 1% of standard stems, though this difference was not significant (p = 0.111). The femoral CFR was greater using shortened stems than using standard stems, both at the level of the tip of the lesser trochanter (0.91 ± 0.05 vs 0.85 ± 0.08; p < 0.001) and at its superior margin (0.76 ± 0.06 vs 0.72 ± 0.07; p < 0.001).

CONCLUSIONS

Compared to the standard stem, the shortened stem had increased metaphyseal filling and equivalent alignment. These findings suggest that shortened stems could provide adequate metaphyseal fixation and correct alignment. Further studies remain necessary to evaluate how shortened stems perform in terms of osseointegration, clinical outcomes and survival.

Does Robotic Milling For Stem Implantation in Cementless THA Result in Improved Outcomes Scores or Survivorship Compared with Hand Rasping? Results of a Randomized Trial at 10 Years

BACKGROUND

Robotic-assisted THA has been promoted as potentially advantageous due to the precision it may afford when machining the proximal femur. However, few reports have compared the long-term clinical results of robotic techniques for femoral component insertion during THA regarding clinical outcomes scores or loosening.

QUESTIONS/PURPOSES

The purpose of this study was to compare results from a randomized clinical trial (RCT) at a minimum followup of 10 years between robot-assisted and hand-rasped stem implantation techniques with regard to (1) Japanese Orthopaedic Association (JOA) clinical outcomes scores, and (2) aseptic loosening, revision surgery, and heterotopic ossification.

METHODS

This is a concise followup of a previously reported RCT. In that trial, robot-assisted primary THA was performed on 75 hips (69 patients), and a hand-rasping technique was used on 71 hips (61 patients). Five experienced surgeons at two institutions participated in this trial; all THAs were performed through the posterolateral approach and the patients were treated similarly apart from the method used to prepare the femur. In all, 115 of 130 (88%) of patients initially randomized were available for followup at a minimum of 10 years (mean, 135 months; range, 120-152 months). There was no differential loss to followup between the study groups, and the final study groups here included 64 hips in 59 patients in the robotic group, and 64 hips in 56 patients in the hand-milling group. There were no differences between the study groups in terms of age, sex, diagnosis, body-mass index, or baseline JOA scores. The primary study endpoint was the JOA score, which is scored from 0 to 100, with higher scores representing better function and less pain. Secondary outcomes were revision surgery, and radiographic signs of aseptic loosening and heterotopic ossification as assessed using the four-grade Brooker scale by individuals other than the operating surgeon.

RESULTS

At a minimum of 10 years postoperatively, there were no differences between patients treated with robot-assisted surgery or hand rasping in JOA scores (97 ± 5 versus 96 ± 7, mean difference 1.4; p = 0.159). No stems in either group developed aseptic loosening, and there were no revisions in either group. There was no difference between the groups in heterotopic ossification (19 of 64 [30%] in the robot-assisted group versus 12 of 64 [19%] in the hand-rasping group; p = 0.186), severe heterotopic ossification was uncommon in both groups, and no hips developed Grade 4 heterotopic ossification in either group.

CONCLUSIONS

Clinically and radiographically, THAs performed with robotic milling for stem implantation did not result in better 10-year clinical outcomes scores, or a lower risk of loosening or revision, compared with hand-rasping. We recommend against widespread adoption of robotic milling for stem implantation in primary cementless THAs.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Dual offset metaphyseal-filling stems in primary total hip arthroplasty in dysplastic hips after a minimum follow-up of ten years

PURPOSE

The aim of this study was to assess the long-term performance of tapered one-third proximally coated stems in dysplastic hips.

METHODS

This study included 135 dysplasia patients (150 hips) who underwent a total hip arthroplasty and had a minimum follow-up of ten years. Single design tapered stems were used in all patients. There were 112 women (83%) and 23 men (17%) with a mean age of 45 years (23 to 72) at the time of surgery. The mean follow-up was 14.7 years (10 to 16.8). For clinical evaluation, the Harris Hip Score and Merle D'Aubigne scale were used pre-operatively and at the final follow-up. Implant survival was calculated using Kaplan-Meier survivorship analysis, with failure defined as a component revision for any reason.

RESULTS

Overall, one stem was revised for a deep infection. There were no other femoral stem revisions secondary to loosening, wear, periprosthetic fracture, or instability. Radiographic evaluation showed excellent stem osteointegration in all cases. Kaplan-Meier survivorship, with stem revision for any reason as the end point, was 98% at 14 years (95% confidence interval 92.5 to 99.8).

CONCLUSION

This study demonstrates that a dual offset tapered stem achieved excellent survivorship and stability, as well as good clinical outcome scores with minimal thigh pain and stress shielding in patients with arthritis and developmental dysplasia of the hip; a dual offset tapered stem may be a suitable option for primary total hip arthroplasty in this group.

Preoperative Canal Bone Ratio is Related to High-Degree Stress Shielding: A Minimum 5-Year Follow-Up Study of a Proximally Hydroxyapatite-Coated Straight Tapered Titanium Femoral Component

BACKGROUND

Few studies have reported risk factors for stress shielding. We sought to evaluate clinical and radiographic outcomes of a proximally hydroxyapatite-coated straight tapered titanium femoral component stem during a minimum 5-year follow-up and identify factors associated with high-degree stress shielding.

METHODS

A total of 156 total hip arthroplasties (n = 124; 98 women and 26 men; mean age, 56.5 years) with a minimum follow-up period of 5 years were included in the study. Clinical and radiologic measurements at follow-up (range, 5-16.3 years; mean, 10.2 years) were analyzed.

RESULTS

The mean preoperative Harris Hip Score (HHS) was 56.6, and the mean HHS at the latest follow-up was considerably improved at 86.8. Stress shielding at the latest follow-up was low degree in 136 (87%) hips and high degree in 20 (13%) hips. On average, high-degree stress shielding occurred 9.9 years (5-14 years) after surgery. The results of Cox proportional hazard analysis showed that a canal bone ratio ≥ 0.49 was an independent risk factor for high-degree stress shielding (P = .0075; hazard ratio, 3.981). HHS at the latest follow-up was significantly lower in high-degree stress shielding than in low-degree stress shielding (80.7 and 87.7, respectively; P = .0030).

CONCLUSION

Preoperative canal bone ratio ≥ 0.49 is independently associated with high-degree stress shielding. In addition, the number of cases with high-degree stress shielding significantly increased over time during a mean 10-year follow-up.

Acoustic pattern evaluation during cementless hip arthroplasty surgery may be a new method for predicting complications

BACKGROUND

Although surgeons must perform implantation of the cementless stem during total hip arthroplasty (THA) without complications, assessment is left to the surgeon's intuitive judgement, which could contain inter/intra-observer bias variety. We therefore asked (1) whether the sound created during the stem implantation could be evaluated objectively and (2) whether those sounds are correlate to the complication specific to the cementless stems. Our hypothesis is that the sounds produced during stem insertion could be quantified and related to the complications.

PATIENTS AND METHOD

In 71 THAs, we quantified the sound produced during stem insertion and investigated the relationship between these sounds and the occurrence of intraoperative fracture and subsidence.

RESULTS

The sound data were divided into two patterns: Patterns A and B. The difference between the peak value (dB) at the most common frequency (near 7 kHz) and the second most common frequency (near 4 kHz) of strikes during the final phase of implantation in Patterns A and B showed a significant difference. Adverse events on intraoperative fracture and subsidence were significantly less common in patients with Pattern A than in those with Pattern B (six of 42 hips with Pattern A and 13 of 29 hips with Pattern B, p = 0.004). Pattern A in predicting a clinical course without those adverse events was 69.2% and the specificity was 68.4%. Positive and negative predictive values were 85.7% and 44.8%, respectively.

CONCLUSION

The sound generated during stem insertion was quantified. Those sound patterns were associated with complications.

The Synergy cementless femoral stem in primary total hip arthroplasty at a minimum follow-up of 15 years

AIMS

We report on the outcome of the Synergy cementless femoral stem with a minimum follow-up of 15 years (15 to 17).

PATIENTS AND METHODS

A retrospective review was undertaken of a consecutive series of 112 routine primary cementless total hip arthroplasties (THAs) in 102 patients (112 hips). There were 60 female and 42 male patients with a mean age of 61 years (18 to 82) at the time of surgery. A total of 78 hips in the 69 patients remain in situ; nine hips in eight patients died before 15 years, and 16 hips in 16 patients were revised. Clinical outcome scores and radiographs were available for 94 hips in 85 patients.

RESULTS

In all, four stems were revised. One stem was revised for aseptic loosening; two stems because of deep infection; and one because of periprosthetic femoral fracture. There was a significant improvement in all components of the Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up (total: p < 0.001, pain: p < 0.001, stiffness: p < 0.001, function: p < 0.001). The mean Harris Hip Scores improved from 47 points (27 to 59) pre-operatively to 89 points (65 to 100) at the latest follow-up (p < 0.001). Kaplan-Meier survivorship, with stem revision for aseptic loosening as the endpoint, was 98.9% at 15 years (95% confidence interval (CI) 96.9 to 100, number at risk at 15 years: 90) and with stem revision for any reason was 95.7% (95% CI 91.7 to 99.8, number at risk at 15 years: 90).

CONCLUSION

The Synergy cementless femoral stem demonstrates excellent survivorship and functional outcomes at 15 years. Cite this article: Bone Joint J 2017;99-B:29-36.

How do different designs of femoral stem affect total hip arthroplasty applied to Crowe type III and type IV dysplastic hips

PURPOSE

A comparison was made of the clinical and radiological results of cylindrical fully porous-coated femoral stems (Group A) and Zweymüller-type femoral stems (Group B) used for the treatment of hip osteoathrosis, secondary to Crowe III and IV dysplasia, with total hip arthroplasty combined with femoral transverse shortening osteotomy.

METHOD

This study is a retrospective evaluation of 86 hips in 50 patients. Group A comprised of 43 hips and Group B comprised of 43 hips. During final follow-up evaluation, patients were clinically assessed with Harris Hip Score (HHS), Merle d'Aubigne-Postel scale (MAP), and SF-36 scale. For radiological examination the Gulman THA score was used. Femoral osteotomy union, osteolysis around the components and component migration were also recorded and evaluated.

RESULTS

In Group B, nonunion of the osteotomy site was found in 18.6% and delayed union in 20.9% of the hips. In Group A, delayed union was found in 7% of the hips. Patients' mean daily walking distance was found to be lower in Group A when compared to Group B. When the postoperative clinical HSS, and MAP and the radiological Gulman scores were compared, no statistically significant differences (p = 0.275) were found.

CONCLUSIONS

Patients with hip osteoarthritis secondary to Crowe III and IV dysplasia, who were treated with THA and transverse osteotomy showed a higher incidence of osteotomy complications when the Zweymüller femoral stem was used. However, these complications did not affect clinical outcomes.