Minimal incision surgery as a risk factor for early failure of total hip arthroplasty

Three Differing Methods of Treating Intraoperative Nondisplaced Calcar Fractures Demonstrate Similar Radiographic Stem Subsidence

BACKGROUND

Several management strategies have been described to treat intraoperative calcar fractures during total hip arthroplasty (THA), including retaining the primary implant and utilizing cerclage cables (CCs) or switching the implant to one that bypasses the fracture and achieves diaphyseal fixation. However, the radiographic and clinical outcomes of these differing strategies have never been described and compared.

METHODS

We retrospectively identified 50 patients who sustained an intraoperative calcar fracture out of 9,129 primary total hip arthroplasties (0.55%) performed by one of three surgeons between 2008 and 2022. Each of the three surgeons consistently employed a distinct strategy for the management of these fractures: retention of the primary metaphyseal-engaging implant and placement of CCs; exchange to a modular, tapered-fluted stem (MTF); or exchange to a fully-coated, diaphyseal-engaging stem (FC). Stem subsidence was then evaluated on standing anteroposterior pelvis radiographs at three months and one year postoperatively. Postoperative medical and surgical complication rates were evaluated.

RESULTS

A total of fifteen patients were treated with CC, 15 with MTF, and 20 with FC. At three-month follow-up, mean stem subsidence was 0.43 ± 0.08 mm, 1.47 ± 0.36 mm, and 0.68 ± 0.39 mm for CC, MTF, and FC cohorts, respectively (P = .323). At one-year, mean stem subsidence was 0.70 ± 0.08 mm, 1.74 ± 0.69 mm, and 1.88 ± 0.90 mm for the CC, MTF, and FC cohorts, respectively (P = .485). Medical complications included 2 venous thromboembolic events (4%) within 90 days of surgery. There were 6 reoperations (12%); 3 (6%) for acute periprosthetic joint infection (all within the FC cohort); 2 (4%) for postoperative periprosthetic fractures (one fracture distal to the stem in the FC cohort and one fracture at the level of the stem in the MTF cohort), and 1 (2%) closed reduction for instability (within the CC cohort).

CONCLUSIONS

The three described methods of managing intraoperative nondisplaced calcar fractures demonstrated little radiographic stem subsidence; however, the risk of reoperation was much higher than expected.

[Advances in study of surgical approaches and MRI evaluation of total hip arthroplasty]

Objective

To review the research on different surgical approaches and MRI evaluation of total hip arthroplasty (THA), to clarify the possible muscle damage caused by different approaches, and to help clinicians avoid intraoperative muscle damage and identify the causes of certain muscle-related complications after operation.

Methods

The research literature on different surgical approaches and MRI evaluation of THA at home and abroad was extensively reviewed to summarize the MRI performance of the posterior approach, modified direct lateral approach, direct anterior approach, and minimally invasive anterolateral approach (also called Orthopadische Chirurgie Munchen approach).

Results

The traditional posterior approach mainly damages the short external rotator muscle group and increases the incidence of postoperative dislocation; the piriformis-keeping posterior approach significantly improves the quality of the pyriformis tendon in the postoperative period, but it may lead to damage to the intrapelvic portion of the piriformis muscle. The modified direct lateral approach mainly damages the gluteus medius muscle, which increases the risk of postoperative claudication. The direct anterior approach mainly damages the vastus tensoris muscle and may result in damage to the short external rotator muscle group and the muscles around the incision. The minimally invasive anterolateral approach primarily damages the superior gluteal nerve, which subsequently leads to denervation of the broad fascial tensor fasciae latae, and this approach may also result in injury to the gluteus medius and gluteus minimus muscles. The muscle damage status significantly affects prognosis, and the minimally invasive approach is more suitable for elderly patients.

Conclusion

MRI can clarify the different types of muscle damage caused by different surgical approaches. Minimally invasive approaches can reduce muscle damage and improve postoperative function compared with traditional approaches, and can benefit elderly patients more, but due to the small field, forcing to expand the surgical field will lead to unintended muscle damage and reduce postoperative function.

Taper-wedge stem suitable for anterior approach total hip arthroplasty: Adequate biomechanical reconstruction parameters and excellent clinical outcome at mid-term follow-up

BACKGROUND

The direct anterior approach (DAA) for total hip arthroplasty (THA) is a less invasive and muscle-sparing approach that seems to improve early function and patient satisfaction. Several studies, however, have reported high complication and revision rates due to the technical difficulties related to the femoral preparation.

AIM

To evaluate the usefulness and safety of a new stem equipped with a morphometric design and a size-specific medial curvature in DAA for THA.

METHODS

This retrospective study was based on 130 patients that underwent mini-invasive DAA procedures for THA using the Accolade II stem. A total of 144 procedures were included in the assessment, which was based on postoperative complications, survival rates, functional parameters, and patient related outcomes.

RESULTS

Overall complications were recorded in 6 procedures (4.2%). There were no complications related to the stem implantation and no intraoperative fractures. Only one patient was revised for deep infection. On radiographs, biomechanical hip reconstruction was satisfactory and no stem showed any subsidence greater than 2 mm. Full osseointegration based on Engh scores was seen in all of the implanted stems. Median Harris hip score at final follow-up was 99 points (range 44-100 points), which resulted excellent in 91.3% of patients. The median values of the osteaorthritis outcome score ranged from 87.5 to 95.

CONCLUSION

The mid-term positive outcomes and low complication rate in our consecutive series of patients support the safety and suitability of this new stem design in DAA for THA.

Is Surgical Approach for Primary Total Hip Arthroplasty Associated With Timing, Incidence, and Characteristics of Periprosthetic Femur Fractures?

BACKGROUND

Periprosthetic femur fractures (PFF) involving primary total hip arthroplasty (THA) remain a significant concern. The purpose of this study was to evaluate the effect of surgical approach during primary THA on early PFF with respect to fracture timing, incidence, radiographic parameters, and surgery-related factors.

METHODS

A retrospective review of all patients with PFF during or after primary THA from 2011 to 2019 was conducted at a single, urban academic institution. Of the study cohort of 11,915 patients, 79 patients with PFF were identified (0.66%). Direct anterior (DA), posterior anterior (PA), and laterally based (LA) cohorts were formed based on the surgical approach. PA and LA groups were combined to form a nonanterior (NA) cohort. Radiographic parameters, surgical factors, and fracture mechanism were analyzed.

RESULTS

The incidence of fracture across approaches was 0.70% (33/4707; DA), 0.63% (35/5600; PA), and 0.68% (11/1608; LA) (P = .97). Time from THA to fracture was significantly shorter in the DA cohort (12.5 ± 14.1 days) than the NA cohort (48.2 ± 120.6 days) (P = .05). Postoperatively identified, atraumatic PFFs were more common in the DA cohort (78.3%, 18/23) than the NA cohort (51.6%, 16/31) (P = .045). There were no differences between groups in radiographic or other clinical parameters.

CONCLUSION

Patients who underwent DA THA have significantly shorter time to PFF and were more often identified postoperatively with an atraumatic mechanism than patients who underwent NA approaches. The known difficulty in femoral exposure and stem placement with the DA approach may play a role in contributing to a higher rate of intraoperative or early postoperative PFF.

Does the Surgical Approach Influence the Canal Fill of the Proximal Femur for Hip Arthroplasty?

Background

Choosing the right size of the stem is crucial for uncemented hip arthroplasty. Undersizing can lead to early loosening, peri-prosthetic fracture due to femoral implant insertion, and/or osteointegration failure. The main objective of this study was to find a correlation between the surgical approach and the intramedullary prosthetic canal fill ratio (CFR) of the uncemented femoral implant. The hypothesis of this work was that the surgical approach does not influence the stem sizing during hip arthroplasty.

Methods

In this consecutive series, we analyzed the radiological images of 183 patients who underwent primary hip arthroplasty with 4 different surgical approaches. Dimensions of the implant were evaluated by radiographic measurement of the CFR. In order to assess the shape of the femur, we measured the canal flare index on the preoperative radiographs, and the canal calcar ratio was also measured to establish the shape of the femur according to Dorr's classification.

Results

No significant difference was found between the surgical approach and the CFR measured at 4 different levels (CFR 1, 2, 3, and 4) on the postoperative radiograph. When the shape of the femur was assessed by canal flare index, there was no significant difference in implant, whether the femur had a stovepipe canal shape or a champagne-fluted canal shape.

Conclusion

This study showed that the surgical approach in hip arthroplasty does not influence the canal fill. Therefore, the surgical approach does not factor in undersizing the femoral implant. Despite some difficulties in the exposure of the medullary shaft described by some authors, the anterior approach is not a risk factor for undersizing an anatomical femoral stem.

Level of evidence

4

Supercapsular percutaneously-assisted total hip (SuperPath) versus mini-incision posterolateral total hip arthroplasty for hip osteoarthritis: a prospective randomized controlled trial

Background

Supercapsular percutaneously-assisted total hip (SuperPath) arthroplasty has been proposed to be minimally invasive and tissue sparing, with possible superior postoperative outcomes compared with conventional approaches for total hip arthroplasty (THA). However, previous studies have underlined the shortcomings of conventional THA approaches, including higher dislocation, more blood loss, longer incisions, more tissue damage, and delayed postoperative rehabilitation. In the present study, we compared the short-term outcomes of unilateral THA with those of SuperPath and the mini-incision posterolateral approach (PLA) for hip osteoarthritis (OA).

Methods

Patients with unilateral hip OA were prospectively recruited and underwent either SuperPath (SuperPath group) or mini-incision PLA THA (PLA group). Perioperative status [operative time, incision length, intraoperative blood loss, soft tissue damage, and length of hospital stay (LOS)], and postoperative function outcomes, including range of motion (ROM), pain visual analog scale (VAS), and Harris Hip Score (HHS), were evaluated and compared between the groups at scheduled time points within 12 months postoperatively.

Results

Compared with the PLA group, the SuperPath group yielded a significantly shorter incision length (7.83 vs. 12.45 cm, P<0.001), longer operative time (102.72 vs. 66.22 min, P<0.001), more blood loss (1,007.38 vs. 844.55 mL, P=0.005), and more soft tissue damage (creatine kinase: 1,056.05 vs. 821.50 U/L, P=0.006) on postoperative day 3. The SuperPath group also showed deficient acetabular cup positioning (abduction angle: 36.94° vs. 42.66°, P=0.004) and a greater decrease in ROM (flexion: 107.66° vs. 114.44°, P=0.004; 109.83° vs. 116.11°, P=0.002; 111.66° vs. 118.88°, P<0.001) on postoperative days 1, 3, and 14, as well as severe early-term pain symptoms (pain VAS on postoperative day 3: 7.05 vs. 6.55, P=0.041). However, the LOS, C-reactive protein levels, erythrocyte sedimentation rate (within 2 weeks postoperatively), and HHS were comparable between the groups during the 12 months postoperatively.

Conclusions

SuperPath may be a promising, minimally invasive technique for the treatment of OA in the future. Further investigation is necessary to evidence the possible superiority of SuperPath over other conventional mini-incision THA approaches.

Early Rate of Revision of Total Hip Arthroplasty Related to Surgical Approach: An Analysis of 122,345 Primary Total Hip Arthroplasties

BACKGROUND

A number of surgical approaches are available for total hip arthroplasty (THA), but there are limited large-volume, multi-surgeon data comparing the rates of early revisions following these approaches. The aim of this study was to compare the rate of revision of primary conventional THA related to surgical approach.

METHODS

Data from the Australian Orthopaedic Association National Joint Replacement Registry were analyzed for all patients who had undergone a primary THA for osteoarthritis from January 2015 to December 2018. The primary outcome measure was the cumulative percent revision (CPR) for all causes. Secondary outcome measures were major revision (a revision procedure requiring change of the acetabular and/or femoral component) and revision for specific diagnoses: fracture, component loosening, infection, and dislocation. Age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, femoral head size, and femoral fixation were assessed as potential confounders.

RESULTS

There was a total of 122,345 primary conventional THAs for which the surgical approach was recorded in the registry; 65,791 were posterior, 24,468 were lateral, and 32,086 were anterior. There was no difference in the overall CPR among approaches, but the anterior approach was associated with a higher rate of major revisions. There were differences among the approaches with regard to the types of revision. When adjusted for age, sex, ASA score, BMI, femoral head size, and femoral fixation, the anterior approach was associated with a higher rate of femoral complications-i.e., revision for periprosthetic fracture and femoral loosening. There was a lower rate of revision for infection after the anterior approach compared with the posterior approach in the entire period, and compared with the lateral approach in the first 3 months. The posterior approach was associated with a higher rate of revision for dislocation compared with both the anterior and the lateral approach in all time periods. The anterior approach was associated with a lower rate of revision compared with the lateral approach in the first 6 months only.

CONCLUSIONS

There was no difference in the overall early CPR among the surgical approaches, but the anterior approach was associated with a higher rate of early major revisions and femoral complications (revisions for periprosthetic fracture and femoral loosening) compared with the posterior and lateral approaches and with a lower rate of dislocation and infection.

LEVEL OF EVIDENCE

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

A survey of Hip Society surgeons concerning the direct anterior approach total hip arthroplasty

Aims

To establish whether there was a consensus among the members of the Hip Society (HS) on the role of direct anterior approach (DAA) contemporary primary total hip arthroplasty (THA).

Methods

An online survey was sent to all 112 active and senior members of the HS, to which 71 members responded. The survey was constructed to determine whether they believed that evidence-based medicine proves, in modern clinical practice, that the DAA has significant benefits compared to risks when contrasted with other approaches. In addition, they were asked if they currently used the DAA.

Results

While only 16.9% (12/71) of respondents had been trained in a generic anterior approach during residency, 49.3% (35/71) had used the DAA in their clinical practice in the past or were using it at the present time. Unexpectedly, 42.9% (15/35) of respondents who had used the DAA in the past had abandoned it by the time of this survey. Only 22.5% (16/71) of all respondents believed that evidence-based medicine proves that the DAA has significant benefits compared to risks in contrast to other approaches.

Conclusion

A comprehensive literature review found only three prospective randomized clinical trials (RCT) comparing the DAA with another approach with greater than one-year follow-up. Two showed minor benefits within the early postoperative period only, and one of those showed poorer mid-term results. Most of the published comparison studies with short follow-up show longer surgical times and greater blood loss for the DAA, and many three-month comparison studies show higher complication rates for the DAA using a proprietary traction table. The complications included problems with wound healing, lateral femoral cutaneous nerve injury, femoral component loosening, and femoral fractures. Because of the lack of evidence from RCTs showing superiority of the DAA over other approaches and reports of higher complications, the opinion of a large majority (77.5%; 55/71) of HS surgeons was that the DAA lacks sufficient evidence to warrant its use. Cite this article: Bone Joint J 2020;102-B(7 Supple B):57–61.

Early Failure of Primary Total Hip Arthroplasty: Is Surgical Approach a Risk Factor?

BACKGROUND

In an era of innovation in surgical approaches for total hip arthroplasty (THA), there is concern for increasing trends of early failure. The purpose of this study is to evaluate the incidence of early failure of primary THA stratified by surgical approach.

METHODS

A retrospective review was performed on consecutive primary THAs completed from 2007 to 2014 at a high-volume center. THAs were stratified by surgical approach. Only the direct anterior (DAA) and posterior approaches (PA) were included. The primary outcome measure was early revision (<5 years). Descriptive statistics were performed using SAS software.

RESULTS

In total, 6894 primary THAs performed between 2007 and 2014 were included. Across 2431 DAA THAs and 4463 PA THAs, there were 103 revisions overall. There was no difference in the overall revision rate for DAA THAs (1.69%) compared to PA THAs (1.39%) (P = .33). The DAA had a higher rate of early revisions for femoral component loosening compared to the PA (P = .0003). About 35.7% of DAA THAs were revised for femoral loosening compared to 8% for the PA (P = .0003). Early failure by femoral loosening occurred more often via the DAA in Dorr A bone (P = .03). The PA had a higher incidence of revision for instability (P = .04). There was no difference in modes of failure with regards to time to failure, acetabular loosening, early periprosthetic fracture, or infection.

CONCLUSION

The DAA had a higher incidence of femoral loosening while PA had a higher mode of failure due to instability. Overall revision rates were not statistically different between approaches.

Minimal Incision Total Hip Arthroplasty: A Concise Follow-up Report on Functional and Radiographic Outcomes at 10 Years

In 2005, we conducted a prospective randomized controlled trial that demonstrated that, compared with a standard incision, a minimal incision technique did not improve early outcomes of total hip arthroplasty (THA). There was concern that reduced exposure could compromise long-term outcome. For the current study, all surviving participants were invited to return for 10-year radiographic and clinical evaluation. Outcome scores were available for 152 patients (69.4%) from the original cohort, and radiographs were available for 126 (57.5%). The median duration of follow-up was 124 months. We did not find significant differences in functional status or radiographic outcome between the minimal and standard incision groups at 10 years. The 10-year implant survival rate was 99.1% (95% confidence interval [CI] = 97.3% to 100%) in the standard incision group and 97.9% (95% CI = 95.1% to 100%) in the minimal incision group (p = 0.57). We concluded that minimal incision THA performed by a high-volume surgeon does not compromise long-term results but offers no benefit over a standard incision.

LEVEL OF EVIDENCE

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

Direct Anterior Approach: Risk Factor for Early Femoral Failure of Cementless Total Hip Arthroplasty: A Multicenter Study

BACKGROUND

The direct anterior approach for total hip arthroplasty (THA) is marketed with claims of superiority over other approaches. Femoral exposure can be technically challenging and potentially lead to early failure. We examined whether surgical approach is associated with early THA failure.

METHODS

A retrospective review of 478 consecutive early revision THAs performed within 5 years after the primary THAs at 3 academic centers from 2011 through 2014 was carried out. Exclusion criteria resulted in a final analysis sample of 342 early-failure THAs. The surgical approach of the primary operation that was revised, the time to the revision, and the etiology of the failure leading to the revision were documented.

RESULTS

Analysis of the revisions due to early femoral failure showed them to be more common in patients who had undergone the direct anterior approach (57/112; 50.9%) than in those treated with the direct lateral (39/112; 34.8%) or the posterior (16/112; 14.3%) approach (p = 0.001). In multivariate regression analysis controlling for age, sex, laterality, Dorr bone type, body mass index (BMI) at revision, bilateral procedure (yes/no), and femoral stem type, the direct anterior approach remained a significant predictor of early femoral failure (p = 0.007). The majority of early revisions due to instability were associated with the posterior (19/40; 47.5%) or direct anterior (15/40; 37.5%) approach (p = 0.001 for the comparison with the direct lateral approach [6/40; 15.0%]).

CONCLUSIONS

Despite claims of earlier recovery and improved outcomes with the direct anterior approach for THA, our findings indicate that that approach may confer a greater risk of early femoral failure and, along with the posterior approach, confer a greater risk of early instability compared with the direct lateral approach.

LEVEL OF EVIDENCE

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

Muscular strength after total hip arthroplasty. A prospective comparison of 3 surgical approaches

BACKGROUND AND PURPOSE

Minimizing the decrease in muscular strength after total hip arthroplasty (THA) might allow patients to recover faster. We evaluated muscular strength in patients who were operated on using 3 surgical approaches. PATIENTS AND METHODs: In a prospective cohort study, 60 patients scheduled for primary THA were allocated to the direct lateral, posterior, or anterior approach. Leg press and abduction strength were evaluated 2 weeks or less preoperatively, 2 and 8 days postoperatively, and at 6-week and 3-month follow-up.

RESULTS

Differences in maximal strength change were greatest after 2 and 8 days. The posterior and anterior approaches produced less decrease in muscular strength than the direct lateral approach. 6 weeks postoperatively, the posterior approach produced greater increase in muscular strength than the direct lateral approach, and resulted in a greater increase in abduction strength than the anterior approach. At 3-month follow-up, no statistically significant differences between the groups were found. The operated legs were 18% weaker in leg press and 15% weaker in abduction than the unoperated legs, and the results were similar between groups.

INTERPRETATION

The posterior and anterior approaches appeared to have the least negative effect on abduction and leg press muscular strength in the first postoperative week; the posterior approach had the least negative effect, even up to 6 weeks postoperatively. THA patients have reduced muscle strength in the operated leg (compared to the unoperated leg) 3 months after surgery.

Tissue preserving total hip arthroplasty using superior capsulotomy

OBJECTIVE

The goals of a tissue-preserving minimally invasive approach to the hip are to allow early short-term recovery, achieve hip joint stability, minimize muscle strength loss from surgery, spare the peri-articular soft tissues, and allow unrestricted motion in the long term.

INDICATIONS

Hip arthroplasty in patients with no pre-existing hardware, with a sufficient space between the acetabular rim and greater trochanter; management of subcapital femoral fractures in older patients.

CONTRAINDICATIONS

Protrusio acetabuli. Joint stiffness. This is the main concern when undertaking the superior capsulotomy. Stiffness may result from bone causes, including ankylosis, large osteophytes, bone bridges etc., extra-articular retraction of surrounding soft tissues with capsular contracture of both ligaments and muscles, or a combination of bony and soft tissues causes, resulting in limited adduction. Indeed, maximal adduction is necessary to increase the distance between the apex of the greater trochanter and the superior acetabular edge. In the approach described in the present article, the real limitation is the impossibility to introduce a straight stem through the trochanteric fossa without weakening the trochantericarea. If adduction is restricted, excessive lateralization of the femoral stem would result in postoperative pain and discomfort, especially as we advocate immediate full weight bearing. Even though patients fare better when the trochanteric area is intact, many types of stem such as the GTS (Biomet), or stem Microplasty (Biomet) or even stem Parva (Adler Ortho) may pressurize the internal bone of the trochanteric structures. Therefore, these stems may be implanted in maximal hip adduction. This is the case in coxa profunda or coxa vara, which require more invasive and destabilizing surgical approaches.

SURGICAL TECHNIQUE

Lateral position, 5-8 cm incision from the tip of the greater trochanter, identification and transaction of piriformis tendon. Anterior mobilization of the gluteus minimus and exposure of the trochanteric fossa. Removal of the superior portion (bone block) of the head and neck, and preparation of the femoral canal. Preparation of the acetabulum. Complete muscle relaxion is helpful to proceed to satisfactory trial reduction.

POSTOPERATIVE MANAGEMENT

Patients may progress to motion and weight bearing without restriction.

RESULTS

From April 2009 to December 2010, the first author operated on 463 patients, 275 for osteoarthrosis of the hip, and 188 for subcapital fractures of the femoral neck. Thereof, 375 (75 %) patients could walk with full weight within 6 h from the operation, and climb stairs 24 h later with low loss of blood, and rapid recovery.

Anterior minimally invasive approach for total hip replacement: five-year survivorship and learning curve

Opponents associate minimally invasive total hip replacement (THR) with additional risks, potentially resulting in increased implant failure rates. The purpose was to document complications, quality of implant positioning and five-year survivorship of THR using the AMIS approach and to test the hypothesis that eventual high complication and revision rates would be limited to an early series and be avoided by junior surgeons who get trained by a senior surgeon. A consecutive series of 150 primary THR implanted during the introduction of the AMIS technique in the department was retrospectively analysed for complications, implant positioning and implant survival after a minimum of five years. Survivorship curves of implants were compared between different surgeons and time periods. Due to implant revision for any reason the five-year survival rate was 94.6%, 78.9% for the first 20 and 96.8% for the following 130 AMIS procedures (p = 0.001). The hazard ratio for implant failure was 0.979 indicating a risk reduction of 2% every further case. The five-year implant survivorship of those procedures performed by two junior surgeons was 97.7%. We conclude that adoption of AMIS temporarily exposed patients to a higher risk of implant revisions, which normalised after the first 20 cases and that experience from a single surgeon's learning curve could effectively be taught to junior surgeons.

Distal extension of the direct anterior approach to the hip poses risk to neurovascular structures: an anatomical study

BACKGROUND

The anterior approach to the hip gained popularity for total hip arthroplasty in recent years. Distal extension of the anterior approach, sometimes needed intraoperatively, potentially endangers neurovascular structures to the quadriceps. The aim of this study was to determine the anatomical structures placed at risk by distal extension of the anterior approach to the hip.

METHODS

Seventeen cadaveric hemipelves from twelve human specimens were dissected. The femoral nerve and its branches and the vessels arising from the lateral femoral circumflex artery were assessed in relation to the distal extension of the anterior approach. The damage caused by the introduction of a cerclage cable passer was also investigated.

RESULTS

The area immediately distal to the intertrochanteric line is a common entry point for several nerve branches and is a useful distal landmark for surgeons to use to protect important neurovascular structures. The distal extension of the anterior approach compromises the nerve supply to the anterolateral portions of the quadriceps. Introduction of a cerclage cable passer through the anterior access also jeopardizes nerve branches to the vastus lateralis, lateral parts of the vastus intermedius, and branches of the lateral femoral circumflex artery.

CONCLUSIONS

Distal extension of the direct anterior approach to the hip is challenging to accomplish without neurovascular injury to anterolateral parts of the quadriceps muscle group. In addition, important neurovascular structures are endangered with the introduction of a cable passer through the anterior approach.

CLINICAL RELEVANCE

Distal extension of the direct anterior approach to the hip beyond the intertrochanteric line may compromise neurovascular structures supplying the quadriceps muscle.

[Complications after minimally invasive total hip arthroplasty]

BACKGROUND

The goal of minimally invasive surgery in total hip arthroplasty (MIS-THA) is reduction of surgical trauma without any limitations regarding exposure of the femur and acetabulum to achieve reproducible results. Despite improved instrumentation the implementation of these techniques is associated with a risk of higher complication rates.

AIM

The article describes specific and unspecific complications of MIS-THA and gives hints and tips on how to avoid them.

MATERIAL AND METHODS

In a retrospective study 152 THA revisions following MIS-THA were examined and an error analysis was performed.

RESULTS

The study of 152 MIS-THA revisions included 87 female and 65 male patients. A gender-specific incidence of complications could not be found. The most common indication for revision surgery was due to recurrent dislocation. An increased incidence of fractures of the greater trochanter was observed using the anterolateral approach with the patient in a supine position.

DISCUSSION

The MIS-THA procedure contributes to excellent early rehabilitation when performed correctly. The muscle preserving aspect can be counted as an advantage particularly for young patients. This patient collective has a high risk to undergo revision surgery.

Risk factors for early revision after primary total hip arthroplasty in Medicare patients

BACKGROUND

Patient, surgeon, health system, and device factors are all known to influence outcomes in THA. However, patient-related factors associated with an increased risk of early failure are poorly understood, particularly in elderly patients.

QUESTIONS/PURPOSES

We identified specific demographic and clinical characteristics associated with increased risk of early revision in Medicare patients with THA.

METHODS

The Medicare 5% national sample administrative database was used to calculate the relative risk of revision within 12 months following primary THA as a function of baseline medical comorbidities in 56,030 Medicare patients who underwent primary THA between 1998 and 2010. The impact of 29 comorbid conditions on risk of early revision was examined using Cox regression, controlling for age, sex, race, US Census region, socioeconomic status, and all other baseline comorbidities.

RESULTS

Depression, rheumatologic disease, psychoses, renal disease, chronic urinary tract infection, and congestive heart failure were associated with revision THA within 12 months of the index arthroplasty (p ≤ 0.038 for all comparisons; risk factors listed in order of significance).

CONCLUSIONS

This information is important when counseling elderly patients with THA regarding the risk of early failure and for risk stratifying publicly reported outcomes in Medicare patients with THA.

[Clinical results of minimally invasive total hip arthroplasty]

AIM

This article presents an analysis and review of recent literature with a focus on clinical results after minimally invasive (MIS) total hip arthroplasty (THA) and with special attention to the different approaches currently used.

METHODS

An online database (Medline) search for clinical trials after THA between 2007 and 2011 was performed with a special focus on prospective controlled randomized trials focusing on THA with a MIS approach. The data were analyzed for pain, blood loss, complications, gait analysis, Harris hip and other scores.

RESULTS

A total of 24 studies (19 comparative studies) were included in this study with a total of 801 MIS THA cases and 695 conventionally operated hips. Almost every study showed superior results for the MIS group with respect to postoperative pain, blood loss and rehabilitation but these advantages almost totally disappeared after 3-6 months. The complication rate was comparable in both groups. After 3-6 months the clinical scores, such as the Harris hip score did not show any differences between conventional and MIS groups.

CONCLUSIONS

In this present study all MIS approaches showed advantages over the conventional surgical approach but these benefits disappeared after 3-6 months. With comparable risks for complications, MIS surgical approaches are superior in the early postoperative phase and rehabilitation.

No significant squeaking in total hip arthroplasty: a series of 413 hips in the Asian people

Some studies have reported the presence of audible squeaking in ceramic-on-ceramic total hip arthroplasty (THA), and several factors such as implant malposition or poor soft tissue recovery have been described as the cause. Our purpose was to determine the squeaking rate in the Asian population with a consecutive series of ceramic-on-ceramic THA. From 2003 to 2009, 413 THAs were performed by a single surgeon using a minimally invasive modified anterior-lateral approach. Using both questionnaire and physical examination, no squeaking was identified in any cases with a minimum of 2-year follow-up. Complications occurred in 4 patients. The results of this study suggested squeaking phenomenon after ceramic-on-ceramic THA may be eliminated.

Adverse outcomes in hip arthroplasty: long-term trends

BACKGROUND

Total hip arthroplasty is a common surgical procedure, but little is known about longitudinal trends in associated adverse outcomes. Our objective was to describe long-term trends in demographics, comorbidities, and adverse outcomes for older patients who underwent primary and revision total hip arthroplasty.

METHODS

We identified a retrospective, observational cohort of 1,405,379 Medicare beneficiaries who underwent primary total hip arthroplasty and 337,874 who underwent revision total hip arthroplasty between 1991 and 2008. The primary outcome was a composite representing the occurrence of one or more of the following adverse outcomes during the index admission or during readmission within ninety days after discharge: death, hemorrhage, infection, pulmonary embolism, sepsis, deep venous thrombosis, and myocardial infarction. Secondary outcomes included each of these outcomes assessed individually.

RESULTS

Between 1991 and 2008, the mean age and the mean comorbidity burden increased for all total hip arthroplasty patients. The length of hospital stay after primary and revision total hip arthroplasty declined by approximately 50% over the study period. However, the rate of readmission for any cause has recently increased and has surpassed 10% for primary total hip arthroplasty and 20% for revision total hip arthroplasty. The composite rate of adverse outcomes after primary total hip arthroplasty declined from 4% to 3.4% over the study period, whereas the composite adverse outcome rate after revision total hip arthroplasty slowly increased from 7% to 10.9%. We observed a steady decline in the rates of most individual adverse outcomes after primary total hip arthroplasty over the majority of the study period. Many of these rates stabilized or began to increase slightly near the end of the study period. In contrast, an increase in the rates of many adverse outcomes was observed in the revision total hip arthroplasty population even after accounting for changes in patient complexity. Postoperative hemorrhage has gradually increased after both primary and revision total hip arthroplasty.

CONCLUSIONS

Patients undergoing primary and revision total hip arthroplasty are becoming more complex. Despite this increasing complexity, patient outcomes for primary total hip arthroplasty improved markedly before stabilizing in recent years. In contrast, patient outcomes after revision total hip arthroplasty have gradually worsened, likely reflecting the increase in the medical comorbidities and surgical complexity of these patients. Length of hospital stay has demonstrated a substantial decline, which has recently been coupled with an increased readmission rate.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Minimally invasive surgical approaches and traditional total hip arthroplasty: a meta-analysis of radiological and complications outcomes

Background

Minimally invasive total hip arthroplasty (MITHA) remains considerably controversial. Limited visibility and prosthesis malposition increase the risk of post-surgical complications compared to those of the traditional method.

Methods

A meta-analysis was undertaken of all published databases up to May 2011. The studies were divided into four subgroups according to the surgical approach taken. The radiological outcomes and complications of minimally invasive surgery were compared to traditional total hip arthroplasty (TTHA) using risk ratio, mean difference, and standardized mean difference statistics.

Results

In five studies involving the posterolateral approach, no significant differences were found between the MITHA groups and the TTHA groups in the acetabular cup abduction angle (p = 0.41), acetabular anteversion (p = 0.96), and femoral prosthesis position (p = 0.83). However, the femoral offset was significantly increased (WMD = 3.00; 95% CI, 0.40–5.60; p = 0.02). Additionally, there were no significant differences among the complications in both the groups (dislocations, nerve injury, infection, deep vein thrombosis, proximal femoral fracture) and revision rate (p>0.05). In three studies involving the posterior approach, there were no significant differences in radiological outcomes or all other complications between MITHA or TTHA groups (p>0.05). Three studies involved anterolateral approach, while 2 studies used the lateral approach. However, the information from imaging and complications was not adequate for statistical analysis.

Conclusions

Posterior MITHA seems to be a safe surgical procedure, without the increased risk of post-operative complication rates and component malposition rates. The posterolateral approach THA may lead to increased femoral offset. The current data are not enough to reach a positive conclusion that lateral and anterolateral approaches will result in increased risks of adverse effects and complications at the prosthesis site.

[Minimally invasive surgery in total hip arthroplasty : Surgical technique of the future?]

AIM

A selective analysis of the latest literature was carried out including prospective clinical controlled studies on the comparison between minimally invasive total hip arthroplasty (MIS) and the conventional technique.

METHODS

An online data base search for controlled study designs within the last 3 years (2009-2011) which compared MIS with standard procedures was performed. Data such as operation time, blood loss, Harris hip score, complications and implant positioning were compared.

RESULTS

A total of 11 studies which compared the results of 387 MISs and 264 operations on hips with the standard technique were analyzed. In the majority of the studies reduced levels of creatine kinase and myoglobin as well as reduced intraoperative blood loss were reported. In the early postoperative period up to postoperative week 6 significant advantages in the Harris hip score were reported for the MIS patients. Postoperative complications and implant positioning were comparable in both groups. The operation time was significantly longer in the MIS group for some studies.

CONCLUSIONS

Minimally invasive techniques in total hip arthroplasty are nowadays no longer seen as just cosmetically attractive but rather as a real improvement for the clinical outcome. In this respect prospective clinically controlled studies within the last 3 years showed advantages in the early postoperative period.

A comparison of a less invasive piriformis-sparing approach versus the standard posterior approach to the hip

We undertook a randomised controlled trial to compare the piriformis-sparing approach with the standard posterior approach used for total hip replacement (THR). We recruited 100 patients awaiting THR and randomly allocated them to either the piriformis-sparing approach or the standard posterior approach. Pre- and post-operative care programmes and rehabilitation regimes were identical for both groups. Observers were blinded to the allocation throughout; patients were blinded until the two-week assessment. Follow-up was at six weeks, three months, one year and two years. In all 11 patients died or were lost to follow-up.

There was no significant difference between groups for any of the functional outcomes. However, for patients in the piriformis-sparing group there was a trend towards a better six-minute walk test at two weeks and greater patient satisfaction at six weeks. The acetabular components were less anteverted (p = 0.005) and had a lower mean inclination angle (p = 0.02) in the piriformis-sparing group. However, in both groups the mean component positions were within Lewinnek’s safe zone. Surgeons perceived the piriformis-sparing approach to be significantly more difficult than the standard approach (p = 0.03), particularly in obese patients.

In conclusion, performing THR through a shorter incision involving sparing piriformis is more difficult and only provides short-term benefits compared with the standard posterior approach.

Anti-Glucosaminidase Monoclonal Antibodies as a Passive Immunization for Methicillin-Resistant Staphylococcus aureus (MRSA) Orthopaedic Infections

Recently, methicillin-resistant Staphylococcus aureus (MRSA) has surpassed HIV as the most deadly pathogen in the United States, accounting for over 100,000 deaths per year. In orthopedics, MRSA osteomyelitis has become the greatest concern in patient care, despite the fact that improvements in surgical technique and aggressive antibiotic prophylaxis have decreased the infection rate for most procedures to less than 5%. This great concern is largely due to the very poor outcomes associated with MRSA osteomyelitis, which includes 30-50% failure rates for revision surgery. Thus, there is a need to develop additional therapeutic interventions such as passive immunization, particularly for immunocompromised patients and the elderly who are typically poor responders to active vaccines. Using a novel murine model of implant-associated osteomyelitis in which a stainless steel pin is coated with bioluminescent S. aureus and implanted transcortically through the tibial metaphysis, we discovered that mice protect themselves from this infection by mounting a specific IgG2b response against the peptidoglycan hydrolase, glucosaminidase (Gmd), an enzyme involved in cell wall digestion during binary fission. Since this subunit of S. aureus autolysin is essential for bacterial growth, and no genetic variation has been identified among clinical strains, we propose that monoclonal antibodies against this enzyme would have multiple mechanisms of action, including promotion of opsonophagocytosis and direct inhibition of enzyme function. Here we review the field of MRSA osteomyelitis and our research to date on the development of an anti-Gmd passive immunotherapy.