Failure of capsular enhanced short external rotator repair after total hip replacement

Dislocation of primary total hip arthroplasty: Analysis of risk factors and preventive options

Total hip arthroplasty (THA) is one of the most successful elective operations in orthopedic surgery for improving pain and functional disability in patients with end-stage joint disease. However, dislocation continues to be a troublesome complication after THA, as it is a leading cause of revision and is associated with substantial social, health, and economic costs. It is a relatively rare, usually early occurrence that depends on both the patients' characteristics and the surgical aspects. The most recent and important finding is the special attention to be given preoperatively to spinopelvic mobility, which is closely related to the incidence of dislocation. Consequently, clinical and radiographic assessment of the lumbar spine is mandatory to identify an altered pelvic tilt that could suggest a different positioning of the cup. Lumbar spinal fusion is currently considered a risk factor for dislocation and revision regardless of whether it is performed prior to or after THA. Surgical options for its treatment and prevention include the use of prostheses with large diameter of femoral head size, dual mobility constructs, constrained liners, and modular neck stems.

Prospective comparative evaluation of intraoperative joint stability and component placement between posterior approach to hip and its quadriceps coxae sparing modification for primary hip arthroplasty

Background

Efforts at minimizing the propensity of posterior approach of hip for post-operative dislocation after total hip arthroplasty have been a subject of continual research. We comparatively evaluated the posterior approach to hip and its quadriceps coxae sparing (QCS) modification with regard to joint stability and component placement.Questions/Purposes: (1) Does sparing of Quadriceps Coxae tendons vis a vis their sectioning in posterior approach help in achieving better intraoperative stability? (2) Does sparing of Quadriceps Coxae tendons come in the way of adequate surgical exposure sufficient to place hip components accurately? (3) Does sparing of Quadriceps Coxae tendons result in better early functional outcome?

Methods

Seventy-two patients requiring THA were enrolled prospectively and randomized into two groups: group A (posterior approach) and group B quadriceps coxae sparing (QCS) approach. They were compared for intraoperative joint stability, accuracy of component placement, duration of surgery, blood loss, any event of hip dislocation, and functional outcome.

Results

QCS approach resulted in better intraoperative hip stability as the hips tolerated a higher value of 43.50±3.5⁰ mean internal rotation (at 90⁰ of flexion and 20⁰ of adduction) in this group versus a mean value of 33.50±5.5⁰ in posterior approach group (p < 0.01). No significant difference was observed for femoral version, acetabular inclination, and acetabular version in the two groups (p > 0.05). There was no difference between the two groups in terms of duration of surgery, intraoperative blood loss, and functional outcome at one year (p > 0.05). No event of hip dislocation was observed in QCS approach, whereas, one such event happened in the posterior-approach group.

Conclusion

Preservation of the QC tendons improves the intraoperative stability of THA and they do not cause any hindrance in the exposure required for optimum component placement.

Insufficient stem antetorsion and lower cup abduction is a combined risk factor for posterior hip dislocation in patients undergoing THA for femoral neck fractures: a retrospective analysis

BACKGROUND

The role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements.

METHODS

We retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured.

RESULTS

The study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters.

CONCLUSIONS

Insufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation.

LEVEL OF EVIDENCE

Prospective comparative study Level II.

The short external rotators in the anterior approach hip arthroplasty: do the tendons heal or not? A prospective MRI study

INTRODUCTION

Release of some of the short external rotator tendons may be needed in the direct anterior approach (DAA) for Total Hip Arthroplasty (THA). It is unknown if these tendons heal. The purpose of this prospective study is to examine short external rotator tendon healing after release and the associated effect on muscle volume. In addition, we examined the relation with external rotation force and patient reported outcome measures (PROMs).

METHODS

In 21 DAA THA patients, preoperative MRI was compared with postoperative MRI at 6 weeks and 12 months. PROMs and rotation force of both hips were assessed. Tendon integrity and muscle volume of the obturator internus and piriformis were assessed on MRI using dedicated software.

RESULTS

In 5 patients all tendons remained intact, in 4 patients only the conjoined tendon was released and in 12 patients both the conjoined and piriformis were released. Obturator externus remained intact in all patients. In patients with tendon release, mean volume of obturator internus and piriformis muscle decreased 27% (SD 11) and 23% (SD 16) 6 weeks after surgery, respectively. Released tendons and muscle volume loss did not recover 12 months after surgery. We found no relation between tendon release and hip rotation force or PROMs.

CONCLUSIONS

We found absent tendon healing and muscle volume loss when the conjoined or piriformis tendons were released. Although we found no relation between tendon detachment and hip force or PROMs, we have adapted our operative technique to make it more preserving for the piriformis.

MRI Findings of Muscle Damage after Total Hip Arthroplasty Using the Complete Muscle Preserving Anterolateral Supine Approach

Background and Objectives: We performed anterolateral total hip arthroplasty (ALS THA) with the purpose of complete muscle-tendon preservation without muscle-tendon dissection. This study aimed to evaluate muscle damage in the periprosthetic hip joint muscles of patients undergoing ALS THA at 1-year post-operative hip magnetic resonance imaging (MRI). Materials and Methods: We evaluated changes in the muscle cross-sectional area (M-CSA) and fatty atrophy of the periprosthetic muscles. We also assessed the Harris hip score on pre-operative and 12-month post-operative MRI in 66 patients who underwent ALS THA. The grade of M-CSA atrophy was classified into no atrophy, slight atrophy, moderate atrophy, and severe atrophy. Fatty atrophy was classified as improved, no change, and worsened using the Goutallier classification. Results: More than 90% of patients’ M-CSA had no atrophy in the obturator internus (Oi), obturator externus (Oe), gluteus medius (Gmed), and gluteus minimus (Gmin), and some improvement was observed in terms of fatty atrophy. In contrast, M-CSA of the tensor fascia latae (TFL) muscle was clearly decreased, and there was no improvement in the TFL fatty atrophy. However, the presence or absence of TFL atrophy did not affect clinical outcome. Conclusions: We performed the complete muscle preserving procedure, ALS THA, with attention to preserving the Oi and Oe by direct visual confirmation and gentle treatment of the Gmed and Gmin with effective retraction. Post-operative M-CSA atrophy evaluation on MRI showed that the Oi, Oe, Gmed, and Gmin were satisfactorily preserved; however, the TFL was clearly atrophic. In the ALS approach, where entry is made between Gmed and TFL, atrophy of the TFL due to superior gluteal nerve injury must be tolerated to some extent.

Conjoined tendon preserving posterior approach in hemiarthroplasty for femoral neck fractures: A prospective multicenter clinical study of 322 patients

PURPOSE

The posterior approach is widely used in femoral hemiarthroplasty. The major problem with this approach is the high risk of postoperative dislocation. A modified posterior approach, the conjoined tendon preserving posterior approach (CPP), was developed to reduce postoperative dislocations. The objective of this multicenter study was to evaluate the efficacy and safety of hemiarthroplasty performed using the CPP approach for femoral neck fractures.

METHODS

A total of 322 patients with femoral neck fracture, from 10 facilities, were prospectively studied. Bipolar hemiarthroplasty using the CPP approach was performed, using the same type of implants. Hip joint movement was not restricted following surgery, regardless of a patient's cognitive status. Final follow-up was performed 9.1 ± 1.5 months after surgery.

RESULTS

Hemiarthroplasty was undertaken in 320 patients using the CPP approach. The mean age, operative time, and intraoperative blood loss were 83.3 ± 7.4 years, 70.0 ± 22.7 min, and 134.8 ± 107.9 mL, respectively. No postoperative dislocations were observed during the study period. Intraoperative adverse events related to the hip joint included femoral fractures in five patients (1.6%) and trochanteric fractures in four patients (1.3%). Postoperative hip joint adverse events included a periprosthetic fracture in one patient (0.3%), deep infection in two patients (0.6%), and stem subsidence in one patient (0.3%). Postoperative deaths occurred in 23 patients (7.2%). One patient (0.3%) had a severe non-hip adverse event unrelated to surgery that prevented independent living, while five patients (1.6%) had a moderate non-hip adverse event that required treatment.

CONCLUSION

The CPP approach prevented postoperative dislocation following femoral hemiarthroplasty in elderly patients, with no CPP-associated specific adverse events.

Clinical results of short external rotators preserving posterolateral approach for hemiarthroplasty after femoral neck fractures in elderly patients

INTRODUCTION

Even though the dislocation rate is lower in the hemiarthroplasty (HA) than total hip arthroplasty, it has still developed as one of serious complications in elderly patients. We have used short external rotators (SER) preserving posterolateral approach to reduce dislocation after hip arthroplasty, especially in elderly patients. The present study was conducted to introduce SER preserving posterolateral approach and report the dislocation rate after HA via this approach in elderly patients with femoral neck fractures.

METHODS

Between January 2015 and July 2019, 307 consecutive elderly patients aged over 70 years who underwent cementless bipolar HA for femoral neck fractures and were followed up for at least one year, were enrolled in this study. All surgeries were performed using the SER preserving posterolateral approach. The demographic and perioperative data were examined and the complications including dislocation were investigated.

RESULTS

Mean operation time was 54.3 min, and mean estimated blood loss was 252.4 cc. The mean follow-up time was 22.1 months, HHS was 67.5 points at the final examination Dislocation following HA developed in only one patient (0.3%) with dementia during hospital stay, which was reduced closely with no subsequent recurrence. Periprosthetic femoral fracture occurred in two patients, which was treated with internal fixation in one patient and with stem revision in the other patient. There was no surgical site infection or periprosthetic infection as complications.

CONCLUSION

The SER preserving technique in posterolateral approach effectively can be effective for reducing the dislocation after HA in elderly patients with femoral neck fracture. It can be encouraged in posterolateral approach for HA, especially in elderly patients under the risk of dislocation.

MRI Assessment of Muscle Damage After the Posterolateral Versus Direct Anterior Approach for THA (Polada Trial). A Randomized Controlled Trial

BACKGROUND

There is controversy in literature whether the direct anterior approach (DAA) results in less muscle damage compared with the posterolateral approach (PLA) for total hip arthroplasty. The aim of this randomized controlled trial was to assess muscle damage between these two approaches.

METHODS

Forty-six patients were included. Muscle atrophy, determined with the Goutallier classification, and muscle surface of twelve muscles were analyzed on magnetic resonance imaging images made preoperatively and one year postoperatively. Differences in component placement after DAA or PLA were assessed on radiographs. Harris hip scores and Hip disability and Osteoarthritis and Outcome Score were used as functional outcomes.

RESULTS

External rotator musculature was damaged in both approaches. After PLA, the obturator muscles showed significantly more atrophy and a decrease in muscle surface. After DAA, the tensor fascia latae showed an increased muscle atrophy and the psoas muscle showed a decreased muscle surface. An increase in muscle surface was seen for the rectus femoris, sartorius, and quadratus femoris after both approaches. The muscle surface of the gluteus medius and iliacus was also increased after PLA. No difference in muscle atrophy was found between the approaches for these muscles. The inclination angle of the cup in PLA was significantly higher. No differences were found in functional outcomes.

CONCLUSION

Different muscle groups were affected in the two approaches. After PLA, the external rotators were more affected, whereas the tensor fascia latae and psoas muscles were more affected after DAA.

Durability of transosseous repair of posterior soft tissues after primary total hip arthroplasty: a prospective randomized controlled trial

PURPOSE

Posterior soft tissue repair is one of the methods for preventing dislocation after total hip arthroplasty (THA). This study aimed to evaluate durability of two separate suture materials in THA patients who underwent posterior soft tissue repair.

METHODS

42 THA patients were included in the study. The patients were randomly divided into two groups, where braided nonabsorbable suture was used in group A (n = 22), while braided absorbable suture was used in group B (n = 20). While repairing the posterior soft tissues, the piriformis and triceps coxae tendons together with the capsule were reattached to the greater trochanter via pull out sutures. Two hemoclips were attached as distance markers to both pull out sutures on the medial and lateal sides of the greater trochanter. Anteroposterior radiographs were taken one day, 15 days, 3 months and 6 months after operation. Distances between the hemoclips medial and lateral to the greater trochanter were measured on the radiographs, and the closest distances were recorded. The repair was considered a failure if the difference of distances between the first and any of the follow-up measurements exceeded 15 mm.

RESULTS

No statistically significant difference was observed between the groups. In both groups, elongation magnitudes in all time intervals were statistically significant while the results obtained from measurements taken 15 days after operation were more significant (p < 0.01). No dislocations were observed.

CONCLUSION

We conclude that for transosseous posterior soft tissue repair in THA, both absorbable and nonabsorbable sutures are similarly durable and can be routinely performed.

Comparative prospective randomized study of minimally invasive transpiriformis approach versus conventional posterolateral approach in total hip arthroplasty as measured by biology markers

Background

Minimally invasive surgery is becoming increasingly common, but evidence of the advantages of the minimally invasive transpiriformis approach in total hip arthroplasty is limited. Therefore, our single-centre randomized controlled trial evaluated the benefits of this approach versus the posterolateral approach.

Methods

Forty-nine patients undergoing the minimally invasive transpiriformis approach and 57 patients undergoing the posterolateral approach total hip arthroplasty were analyzed. The operative time, length of hospital stay, incision length, and peri-operative data related to the surgery were recorded. In both groups, serum CRP, IL-6, HGb, Hct, MB, CK-MB, and CK levels, Harris hip scores, and VAS scores were recorded.

Results

Patients who underwent the minimally invasive transpiriformis approach had a smaller surgical incision (9.10 ± 0.94 vs. 15.56 ± 1.20 cm, P = 0.00) and shorter hospital stay (6.20 ± 1.54 vs. 12.26 ± 2.97 days, P = 0.00) than those who underwent the posterolateral approach. Serum levels of CRP, IL-6, MB, CK-MB, and CK were also lower. According to the Harris hip score, the minimally invasive transpiriformis group showed significant improvement at one week and one month after surgery.

Conclusion

Compared to the posterolateral approach, the minimally invasive transpiriformis approach for total hip arthroplasty provided rapid functional recovery, elicited a significantly reduced post-operative inflammatory response, and caused less muscle damage.

[Prognostic evaluation of hip joint function following capsule repair based on a threedimensional finite element analysis model]

OBJECTIVE

To construct a three-dimensional (3D) finite element mechanical model of total hip arthroplasty for comparison of biomechanical differences of the hip joint following capsule repair and postoperative rehabilitation.

METHODS

Six frozen specimens of hip joint posterior capsule ligament complex were collected in a bone-capsule-bone manner, and the load-strain curve and other mechanical properties of the specimens were tested using a universal material testing machine. Thin-section CT data of the pelvis and lower limbs obtained from a volunteer were imported into Mimics software to construct a 3D model of the hip joint. Digital models of the cup, femoral prosthesis and joint capsule were created in CATIA software and imported into Mimics to simulate total hip arthroplasty; the assembled data were imported into ABAQUS software. The properties of the capsule were set according to results of the mechanical test, anatomical studies, and constitutive equations, and the biomechanics of the anatomically repaired and conventionally repaired capsules were compared during hip flexion.

RESULTS

The results of testing on the 6 capsule specimens showed a mean ultimate tensile strain of (39.21±5.23)% and a mean of ultimate tensile strength of 1.65±0.38 MPa. The stress-strain curve of the finite element model was consistent with the results of mechanical test on the specimens and the biochemical characteristics of the capsule. The stress was distributed evenly in the anatomically repaired capsule during hip flexion but not in the capsule repaired through the conventional approach; the tensile stress in the lower part of the conventionally repaired capsule reached the ultimate tensile stress measured on the capsule specimens at a 90° flexion.

CONCLUSIONS

The finite element model allows dynamic, quantitative and visual assessment of stress distribution in the hip joint capsule, and compared with the conventional approach, anatomical repair can achieve better biomechanical properties of the capsule.

Minimally invasive posterolateral hip approach with SPARTAQUUS (Spare the Piriformis And Respect The Active QUadratus femoris and gluteus mediUS) technique

Interest in the different surgical approaches to total hip arthroplasty remains high, but without any real consensus on which approach is the most beneficial. Several recent technical innovations have made it possible to reduce the risk of dislocation, therefore improving the efficacy of the posterolateral approach. Since 2003, we have been using a modified minimally invasive posterolateral approach called SPARTAQUUS (Spare the Piriformis And Respect The Active QUadratus femoris and gluteus mediUS), which spares the piriformis tendon, the quadratus femoris muscle and the gluteus medius muscle, and involves direct capsular repair. The "active posterosuperior hammock" effect of the piriformis tendon is therefore coupled with the "passive posterosuperior hammock" effect of the capsular repair, thus limiting the risks of posterior dislocation of the prosthetic hip joint.

A Specific Capsular Repair Technique Lowered Early Dislocations in Primary Total Hip Arthroplasty Through a Posterior Approach

BACKGROUND

Dislocation is a challenging problem after total hip arthroplasty (THA). We sought to evaluate the incidence of early dislocation with 2 different posterior repair techniques after THA using a posterior approach.

METHODS

From September of 2008 to August of 2019, we evaluated 841 THAs performed by a single surgeon using a posterior approach. Before November of 2015, the capsule was repaired to the greater trochanter (group 1, 605 patients). Starting November 2015, the posterior capsule was repaired in a side-to-side fashion (direct soft-tissue repair) (group 2, 236 patients). There was a mean follow-up of 31.1 months (range, 2.5-122.5 months). A multivariable logistic regression model was constructed to assess the impact of baseline patient and operative factors on the dislocation rate.

RESULTS

There were 22 dislocations, all of which occurred in group 1. There were no dislocations in group 2. After adjusting for patient and operative factors, the direct soft-tissue repair had a large impact on the overall multivariable model as indicated by its effect likelihood ratio of 10.33 (P = .001); however, the odds ratio was not calculable for this factor, given that there were no dislocations in hips with direct soft-tissue repair. Increasing age was associated with an increased odds of dislocation (odds ratio, 1.04, P = .017), with an effect likelihood ratio of 6.25 (P = .012).

CONCLUSIONS

Switching from a capsular repair to the greater trochanter to a side-to-side capsular repair was associated with a decreased rate of dislocation in primary THA through a posterior approach.

Postoperative Failure Frequency of Short External Rotator and Posterior Capsule With Successful Reinsertion After Primary Total Hip Arthroplasty: An Ultrasound Assessment

BACKGROUND

The reinsertion of the short external rotators and posterior capsule to the greater trochanter in the posterolateral approach has been considered an effective strategy to reduce the risk of dislocation. However, during clinical practice, no verification and monitoring of the status of such reinsertions is carried out. The objective of this study is to estimate the frequency of postoperative failure with successful reinsertion of the short external rotator and posterior capsule of the hip through ultrasound after primary total hip arthroplasty (THA) using the posterolateral approach.

METHODS

A prospective observational study was conducted involving patients with primary total hip arthroplasty via posterolateral approach in which reinsertion of hip's short external rotators and posterior capsule were successful reinserted during surgery from January to December 2019. The status of the reinsertion was assessed with an ultrasound between the 6 and 8 weeks after surgery. Reinsertion failure was considered when the reinserted structures were not fully visualized in the ultrasound during internal and external rotation.

RESULTS

Sixty-eight patients were included in this study (mean age: 58.7 ± 13.8 years; 44.1% (30) women). The incidence of failure of the reinsertion of short external rotators and posterior capsule was 16.2% (n = 11) (95% confidence interval 9.3-26.7). A postoperative increased femoral offset was found more frequently in cases with failure (36.4% vs 17.5%); a similar trend was observed in the leg length discrepancy (36.4% vs 22.8%). However, these differences were not statistically significant (P > .05).

CONCLUSION

Between the 6th and 8th postoperative week, approximately 2 of the 10 short external rotator and posterior capsule reinsertions fail in cases with successful intraoperative repair using absorbable suture. This estimate is comparable and even lower than previous reports.

EVIDENCE LEVEL

II, Prospective Observational Study.

The effect of posterior capsule repair in total hip arthroplasty: a systematic review and meta-analysis

Background

Prior studies have compared the posterior capsule repair group in primary total hip arthroplasty by posterior approach with the control group without posterior capsule repair suggesting that the posterior capsule repair group had better clinical outcomes. However, it is still a controversy which treatment is more helpful for hip diseases. The purpose of our article is to obtain the postoperative outcomes between the 2 procedures.

Methods

We performed a systematic search by browsing the MEDLINE, EMBASE, Cochrane Library. There is no restriction on the date of publication. Before we submit our manuscript, we have re-searched the literatures again, including the articles which directly compared the postoperative outcomes of the 2 procedures.

Results

A total of 8 comparative studies were included in our meta-analysis. The posterior capsule repair group showed less dislocation rate, higher HHS, and even less postoperative bleeding volume. Meanwhile, there is no significant difference in ROM between 2 groups.

Conclusion

In conclusion, according to current evidences, repairing posterior capsule during primary THA may have better functional outcomes, less dislocation incidence, and less loss of blood.

Modified osteotomy of posterolateral overhanging part of the trochanter via posterior approach for hip arthroplasty: an anatomical study

Backgroud

The osteotomy of the posterolateral overhanging part (PLOP) of the greater trochanter via posterior approach has been used for the hip arthroplasty for decades with good results. However, the osteotomy method remains undefined and the precise adjacent structures around PLOP have not been reported. The purpose of this study was to present a modified PLOP osteotomy approach and perform a detailed study of the topographic and surgical anatomy of the PLOP.

Methods

The peri-PLOP soft tissue and the bony parameters were measured using 10 cadavers with 20 hips and 20 skeletal hip specimens, respectively.

Results

A 1.8-cm vertical osteotomy did not jeopardize the femoral neck, and a 1.8-cm wide bone block did not damage the insertions of the short external rotators. The average distances between the most distal branch of the superior gluteal nerve/artery and the 1.8-cm point of the greater trochanter were 5.70 ± 0.66 cm and 6.33 ± 0.56 cm, respectively.

Conclusion

For osteotomy of the PLOP, we suggested that the width of the upper side from the lateral to medial greater trochanter should be 1.8 cm, depth of vertical osteotomy should be 1.8 cm, and length of the posterior edge should be 4 cm. Obturator externus tendon should be kept within the bone block of osteotomy. The proximal extension of the gluteus medius muscle split should be limited to 5.5 cm at the 1.8 cm-point of the greater trochanter.

Level of evidence

Prospective comparative study Level II.

The direct superior approach in total hip arthroplasty

The direct superior approach is a modification of the minimally invasive posterior approach for total hip arthroplasty which preserves the iliotibial band and external rotators except for the piriformis or conjoint tendon. This review explores the existing scientific evidence on clinical, functional and radiological outcomes in total hip arthroplasty performed using the direct superior approach. The direct superior approach reduces iatrogenic periarticular soft tissue injury compared to the direct anterior approach for total hip arthroplasty. The learning curve for the direct superior approach is 40 operative cases with operative times comparable to those of conventional approaches for total hip arthroplasty after surgical proficiency has been achieved. The direct superior approach provides improvements in pain and short-term functional outcomes after total hip arthroplasty as assessed using the Harris Hip Score. The minimally invasive posterior approach provides comparable pain scores and improved University of California, Los Angeles (UCLA) activity scale functional scores to the direct superior approach at 1-year follow up. Existing studies using plain radiographs have shown that the direct superior approach enables accurate femoral and acetabular implant positioning.

Tension-free closure with capsular lengthening in mini posterior total hip replacement

PURPOSE:

Choice of the best mini invasive surgical approach for total hip replacement remains a controversial topic. The posterior approach is traditionally associated with a higher dislocation rate and the obligation of postoperative restrictions. Soft tissue repair reduces the risk of dislocation yet, posterior closure it is often challenging because of capsular and external rotator contractures. In this article, an original procedure of capsular lengthening and tension-free closure is described and the results of a retrospective single surgeon series of minimally invasive posterior total hip replacement (THR) with capsular repair are presented.

METHODS:

A total of 925 mini posterior total hip replacements performed between 2009 and 2015 were retrospectively reviewed. 2 original types of capsulorrhaphy to decrease tension of the repaired tissues were employed. Absence of posterior envelope stretch during flexion and internal rotation was confirmed intraoperatively with a dynamic test. No postoperative restrictions were used.

RESULTS:

Capsular lengthening with 1 of the described techniques was required in over 50% of cases for a tension-free closure. 3 patients dislocated in the 867 reviewed procedures (0.35%), 1 requiring revision for instability (0.11%).

CONCLUSIONS:

This soft tissue repair technique after mini posterior approach THR is technically easy, provides a tension-free closure and a low dislocation rate.

The incidence of hip dislocation and suture failure according to two different types of posterior soft tissue repair techniques in total hip arthroplasty: a prospective randomized controlled trial

PURPOSE

Although the posterolateral approach for hip arthroplasty is popular and has numerous advantages, it has been known to have a propensity for dislocation. The repair of short external rotator muscles with capsule is important for reducing dislocation. The purpose of this study is to investigate the incidence of suture failure, dislocation, and time to failure for two repair techniques for posterior soft tissue repair during total hip arthroplasty.

METHODS

In this study of 167 total hip arthroplasties in 159 patients, we reattached the short external rotator tendon with posterior capsule to the greater trochanter transosseously (tendon-to-bone, 87 hips) or the gluteus medius tendon (tendon-to-tendon, 80 hips). Radiopaque markers were attached to each suture side < 1.2 cm apart. The distance between the markers was radiographically measured at variable time points postoperatively. Failure was defined by a distance between markers of ≥ 2.5 cm or marker invisibility. The mean follow-up period was 28.8 (12-45) months.

RESULTS

Suture failure was observed less frequently in the tendon-to-bone group (18.4%) than in the tendon-to-tendon group (65%; p < 0.001). Failure mostly occurred within two weeks post-operatively: 93.8% for tendon-to-bone repair (p < 0.001) and 90.4% for tendon-to-tendon repair (p = 0.025). The dislocation rate was significantly higher in the tendon-to-tendon group (7. vs 1.1%; p = 0.041). A significant correlation was observed between suture failure and dislocation (p = 0.013).

CONCLUSIONS

Tendon-to-bone repair is superior to tendon-to-tendon repair based on lower suture failure and dislocation rates.

Primary total hip arthroplasty using modified posterior approach through quadratus femoris flap osteotomy; comparison with conventional posterior approach

INTRODUCTION

The quadratus femoris muscle has not attracted attention as a structure for surgical exposure during posterior hip approaches. We sought to introduce a modified posterior approach through the quadratus femoris muscle area only, by flap osteotomy, which we have named the quadratus femoris osteotomy (QFO) approach. We compare this with the conventional posterior approach to determine the effectiveness of the new technique.

METHODS

We retrospectively reviewed the medical records of 329 patients (383 hips) who had undergone primary total hip arthroplasty (THA) between March 2006 and January 2013 by a single hip surgeon. The conventional group consisted of consecutive 118 patients (138 hips) who had undergone THA using the conventional posterior approach. The QFO group consisted of consecutive 101 patients (120 hips) who were treated with THA using the QFO approach.

RESULTS

The 2-year postoperative average Harris hip score were 88.8 ± 6.6 in the conventional group and 93.1 ± 6.9 in the QFO group. The 2-year postoperative average WOMAC scores were 20.8 ± 6.7 in the conventional group and 14.1 ± 6.6 in the QFO group. Complications in the conventional group were 2 deep vein thrombosis (DVT)s, 1 intraoperative fracture, and 6 posterior dislocations; the QFO group experienced 1 DVT and 3 intraoperative fracture. No dislocation was noted within 2 years after surgery.

CONCLUSIONS

Although further studies are needed to confirm the validity of our findings, a modified posterior approach using a quadratus femoris flap osteotomy could be an option worth considering among the variants of posterior approaches in THA.

The analysis of posterior soft tissue repair durability after total hip arthroplasty in primary osteoarthritis patients

BACKGROUND AND PURPOSE

The posterior soft tissue repair is 1 of the preventing factors for dislocation after total hip arthroplasty (THA).The aim of our study was to analyse THA patients with posterior soft tissue repair in terms of suture durability, time of suture failure and correlate the changes in leg length and offset postoperatively to suture durability.

METHODS

A total of 37 consecutive THA patients operated for osteoarthritis were included in the study. The posterior repair included reattaching the piriformis, conjoined tendons and posterior capsule to the greater trochanter through 2, 2 mm drill holes with 2 grasping stitches. A metal indicator wire was stitched into the piriformis tendon at distance of 1 cm from the greater trochanter after the prosthesis had been implanted and the joint reduced. Anteroposterior radiographs were taken immediately after the patients returned from the operating theatre to the intensive care unit, the next day after mobilisation, and at the 5th day of stay and at 3 months postoperatively.

RESULTS

Out of 37 THA hips, 6 (16%) had failed immediately after surgery, 25 (68%) at the 1st postoperative day after mobilisation, 2 (5%) at the 5th postoperative day, and 1 (3%) repairs had failed at 3 months after THA. In the remaining 3 hips no failure occurred.

INTERPRETATION

We conclude that posterior soft tissue repair in THA often fails and suggest that new posterior soft tissue repair methods be developed.

MR imaging of hip arthroplasty implants

Hip arthroplasty has become the standard treatment for end-stage hip disease, allowing pain relief and restoration of mobility in large numbers of patients; however, pain after hip arthroplasty occurs in as many as 40% of cases, and despite improved longevity, all implants eventually fail with time. Owing to the increasing numbers of hip arthroplasty procedures performed, the demographic factors, and the metal-on-metal arthroplasty systems with their associated risk for the development of adverse local tissue reactions to metal products, there is a growing demand for an accurate diagnosis of symptoms related to hip arthroplasty implants and for a way to monitor patients at risk. Magnetic resonance (MR) imaging has evolved into a powerful diagnostic tool for the evaluation of hip arthroplasty implants. Optimized conventional pulse sequences and metal artifact reduction techniques afford improved depiction of bone, implant-tissue interfaces, and periprosthetic soft tissue for the diagnosis of arthroplasty-related complications. Strategies for MR imaging of hip arthroplasty implants are presented, as well as the imaging appearances of common causes of painful and dysfunctional hip arthroplasty systems, including stress reactions and fractures; bone resorption and aseptic loosening; polyethylene wear-induced synovitis and osteolysis; adverse local tissue reactions to metal products; infection; heterotopic ossification; tendinopathy; neuropathy; and periprosthetic neoplasms. A checklist is provided for systematic evaluation of MR images of hip arthroplasty implants. MR imaging with optimized conventional pulse sequences and metal artifact reduction techniques is a comprehensive imaging modality for the evaluation of the hip after arthroplasty, contributing important information for diagnosis, prognosis, risk stratification, and surgical planning.

Posterior Soft Tissue Repair After Primary THA is Durable at Mid-term Followup: A Prospective MRI Study

BACKGROUND

The enhanced posterior soft tissue repair has reduced the frequency of dislocation after primary THA performed through the posterolateral approach. However, the long-term integrity of the repair is unknown and could influence surgeon choice regarding surgical technique and THA approach.

QUESTIONS/PURPOSES

We asked: (1) What is the durability of the enhanced posterior soft tissue repair at a minimum of 49 months using MRI to evaluate soft tissue to bone integrity? (2) How does the appearance of the posterior soft tissues change during this time? (3) Are there patient characteristics associated with the long-term imaging appearance of the posterior repair?

METHODS

All patients without a contraindication for MRI who were undergoing unilateral primary uncemented THA through a posterior approach between February and May 2005 were eligible for inclusion. Ninety percent consented to participate (36 of 40 patients), and 30 patients were followed prospectively with MRI postoperatively and again at 3 months; of those, 22 (73%; 12 men, 10 women) completed the study by having another MRI study at a minimum of 49 months (mean, 51 months; range, 49-59 months). Each patient underwent metal-artifact-reduction sequence MRI to evaluate the integrity of the posterior soft tissues, which had been repaired anatomically during primary THA at a minimum of 4 years earlier. The results were compared with those of prior MR images obtained immediately after surgery and at 3 months postoperatively. All patients were given a self-reported modified Harris hip score at the time of the most recent MRI study (maximum score = 81).

RESULTS

At latest followup, 21 of 22 (96%) patients had a posterior capsule in contact with bone, and 21 of 22 (96%) had an intact quadratus femoris. Twenty-one patients (96%) had soft tissue or a scar from the piriformis and conjoined tendons in continuity with bone. In these cases, the interface between the piriformis and conjoined tendons and the greater trochanter observed immediately postoperatively and at 3 months postoperatively became filled with hypointense tissue, with signal characteristics similar to tendon. Time from surgery was most associated with changes in native tendon-to-bone distances (p < 0.001) and MRI signal intensity of the repair (p < 0.001).

CONCLUSIONS

At followup of just more than 4 years, the posterior capsule and quadratus femoris most often were healed to bone. In the majority of patients, scar tissue between the piriformis and conjoined tendons and bone matured to achieve orientation and signal intensity resembling native tendon. We believe the enhanced posterior soft tissue repair facilitates this process. Our results provide a plausible explanation for improved postoperative stability observed in patients receiving an enhanced soft tissue repair compared with those in whom a repair is not performed.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Evolution of the human hip. Part 2: muscling the double extension

Part 1 of this article outlined the extensive osseous adaptations around the hip that occurred in the development of a habitual bipedal gait in modern humans. The shortest summary of these osseous changes is 'double extension', i.e. extension of both the hip joint and the lumbar spine. Not surprisingly, these osseous changes went hand in hand with major muscular changes. The primary changes that accompanied the double extension were changes in relative muscle volume for the quadriceps, gluteus maximus and hamstrings, changes in moment arms for the iliopsoas, gluteus maximus and hamstrings, a change in function for the gluteus medius and minimus, while the functional anatomy of the adductors and hip rotators changed only slightly. The effect of these osseous and muscular changes was improved energy efficiency of human bipedal walking and (long distance) running. However, this occurred at the expense of maximum power, characteristic for activities such as tree climbing (in the apes), but equally so for sprinting. Recognizing these changes and their consequences may help us better understand and treat soft-tissue disorders around the hip.

The surgical anatomy of the piriformis tendon, with particular reference to total hip replacement

The piriformis muscle is an important landmark in the surgical anatomy of the hip, particularly the posterior approach for total hip replacement (THR). Standard orthopaedic teaching dictates that the tendon must be cut in to allow adequate access to the superior part of the acetabulum and the femoral medullary canal. However, in our experience a routine THR can be performed through a posterior approach without sacrificing this tendon.

We dissected the proximal femora of 15 cadavers in order to clarify the morphological anatomy of the piriformis tendon. We confirmed that the tendon attaches on the crest of the greater trochanter, in a position superior to the trochanteric fossa, away from the entry point for broaching the intramedullary canal during THR. The tendon attachment site encompassed the summit and medial aspect of the greater trochanter as well as a variable attachment to the fibrous capsule of the hip joint. In addition we dissected seven cadavers resecting all posterior attachments except the piriformis muscle and tendon in order to study their relations to the hip joint, as the joint was flexed. At flexion of 90° the piriformis muscle lay directly posterior to the hip joint.

The piriform fossa is a term used by orthopaedic surgeons to refer the trochanteric fossa and normally has no relation to the attachment site of the piriformis tendon. In hip flexion the piriformis lies directly behind the hip joint and might reasonably be considered to contribute to the stability of the joint.

We conclude that the anatomy of the piriformis muscle is often inaccurately described in the current surgical literature and terms are used and interchanged inappropriately.

Cite this article: Bone Joint J 2013;95-B:764–9.

Intertrochanteric partial osteotomy for posterior hip approach

The posterior dislocation remains one unresolved complication of the posterior approach to the hip joint. In this study, a variation of the posterior hip approach - a partial osteotomy of the greater trochanter - was performed in order to investigate whether it provides better stability to the operated hip joint and reduces the risk of dislocation. We carried out a partial intertrochanteric osteotomy, initially in a cadaveric model and then in 68 patients (30 acute neck of femur fractures and 38 patients with hip osteoarthritis) requiring a total hip replacement. The osteotomised fragment was reattached with wires. All arthroplasties were cemented with Müller acetabular component and Charnley-type stem with a 28-mm interchangeable neck. Intraoperatively, all hips were tested for stability. After the osteosynthesis of the osteotomised fragment, hip dislocation points were increased more than 15% in the flexion and 10% in the internal rotation plane of movement. At one year follow up, no dislocation was observed in the clinical component of the study. This technique was found reliable in providing a stable hip joint.

Assessment of pronator quadratus repair integrity following volar plate fixation for distal radius fractures: a prospective clinical cohort study

PURPOSE

To assess prospectively the integrity of pronator quadratus (PQ) muscle repair following volar plate fixation of distal radius fractures and to compare the clinical and radiographic outcomes of durable versus failed repairs in 24 subjects. In addition, by grading the degree of PQ injury, an attempt was made to correlate failure of repair with the PQ injury severity.

METHODS

The extent of PQ injury was graded for each fracture. After fracture fixation, the PQ muscle was repaired along its radial and distal borders. Radiopaque hemoclips were attached to each side of the PQ repair, 2 radially and 2 distally. The distance between these markers at time 0 versus x-rays taken at approximately 2 weeks, 6 weeks, and 3 months was recorded. Clip displacement of 1 cm or more compared to time 0 indicated repair failure.

RESULTS

One of 24 repairs (4%) failed at 3 months. No statistical difference was noted between the type of PQ injury and wrist flexion/extension, pronation/supination, and grip strength.

CONCLUSIONS

Pronator quadratus repairs after volar plate fracture fixation are generally durable. They withstand forces that occur at the distal radius during the healing process with a 4% failure rate. No correlation was shown between type of PQ injury and radiographic failure of the repair.

Minimally invasive total hip arthroplasty using a transpiriformis approach: a preliminary report

BACKGROUND

Continuing efforts have been made to develop minimally invasive surgery techniques for THA. One of the most commonly performed of these techniques is the mini-posterior approach. All reported series using this approach describe surgical detachment of the short external rotators of the hip. In 2008, Penenberg et al. described an innovative surgical technique that preserves the short external rotators. We present the results of a single-incision modification of this technique in 135 patients.

DESCRIPTION OF TECHNIQUE

This technique is based on preservation of all of the short external rotators of the hip with the exception of the piriformis or conjoined tendon. This single-incision technique required the development of specialized instrumentation for exposure and reaming of the acetabulum. The specialized retractors also successfully minimized trauma to the skin and subcutaneous tissue.

METHODS

For the 135 patients undergoing THA with this technique, we analyzed demographic and operative data. We recorded complications, evaluated postoperative clinical function using the Harris hip score, and assessed cup abduction angle, cup anteversion, and stem alignment on radiographs. Minimum followup was 14 months (mean, 22 months; range, 14-33 months).

RESULTS

There were no dislocations, no sciatic nerve palsies, no wound complications, and low transfusion rates (8%). The postoperative Harris hip score averaged 96.5 (range, 87-100). Overall acetabular cup abduction angle averaged 41° (range, 21°-49°) and anteversion averaged 21° (range, 15°-27°). Four percent and 2% of femoral components were inserted into more than 2° varus and 2° valgus alignment, respectively.

CONCLUSIONS

This technique shows promise as an alternative tissue-sparing method for minimally invasive THA.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The effect of hip position on the length of trochanteric muscles: potential implications for early postoperative management of hip arthroplasty

We investigated the effect several lower limb positions have on muscles that are detached to perform hip arthroplasty through posterior and lateral approaches. We used string models and computer navigation to measure the length changes in these muscles throughout hip movements in the anatomical planes and while simulating several sitting and lying postures. Piriformis and the obturators were shortened by sitting and lying postures when the femur was externally rotated and abducted; the clinical implication being that such postures have the potential to best protect their repair after a posterior approach. The anterior part of gluteus medius was lengthened with femoral external rotation. This lengthening was prevented, and therefore, theoretically, the gluteus medius repair protected after a lateral approach, by neutral or internal femoral rotation.

Relationship between the hip joint capsule and piriformis tendon in a simulation of the modified Watson-Jones anterolateral approach in THA cadaver study

Fifteen fresh frozen cadavers were used for a simulation of the modified Watson-Jones anterolateral approach in an anatomical study. Several parameters were measured to evaluate the relation between the piriformis tendon insertion and hip joint capsule insertion. The anteroposterior diameter of the piriformis tendon was found to be greater than the medial-lateral diameter, and that the posterior part of the incised hip joint capsule is distant from the piriformis tendon as the piriformis is inserted into the extra-articular portion. We also found that it was important not to dissect the anteroproximal portion of the greater trochanter to prevent rupture of the piriformis tendon, whereas the posterior portion was relatively safe.

Surgical technique: a simple soft-tissue-only repair of the capsule and external rotators in posterior-approach THA

BACKGROUND

Posterior soft tissue repair after posterior THA reportedly decreases the risk of dislocation. Previously described techniques often require drill holes through the greater trochanter, do not include both the short external rotators and the capsule, or require a complex series of multiple sutures. We therefore describe a technique to address these issues.

DESCRIPTION OF TECHNIQUE

The posterior soft tissues were repaired with a single nonabsorbable suture passed through the external rotators and posterior capsule and then through the capsule and posterior border of minimus in a figure-of-eight pattern. This repair remains pliable and obliterates the dead space.

METHODS

We retrospectively reviewed 165 patients who underwent 178 primary THAs through a mini-posterior THA and also underwent soft tissue repair using our technique. We determined the rate of dislocation and complications associated with this technique. The minimum clinical followup was 1 year (mean, 23 months; range, 12-37 months).

RESULTS

This repair was associated with a low risk of dislocation at 1 year (one of 178 hips, 0.56%) and no apparent complications related to the technique.

CONCLUSIONS

This soft tissue to soft tissue repair technique after posterior-approach THA is technically straightforward and reliable with a low associated dislocation rate.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The capsule's contribution to total hip construct stability--a finite element analysis

Instability is a significant concern in total hip arthroplasty (THA), particularly when there is structural compromise of the capsule due to pre-existing pathology or due to necessities of surgical approach. An experimentally grounded fiber-direction-based finite element model of the hip capsule was developed, and was integrated with an established three-dimensional model of impingement/dislocation. Model validity was established by close similarity to results from a cadaveric experiment in a servohydraulic hip simulator. Parametric computational runs explored effects of graded levels of capsule thickness, of regional detachment from the capsule's femoral or acetabular insertions, of surgical incisions of capsule substance, and of capsule defect repairs. Depending strongly upon the specific site, localized capsule defects caused varying degrees of construct stability compromise, with several specific situations involving over 60% decrement in dislocation resistance. Construct stability was returned substantially toward intact-capsule levels following well-conceived repairs, although the suture sites involved were often at substantial risk of failure. These parametric model results underscore the importance of retaining or robustly repairing capsular structures in THA, in order to maximize overall construct stability. 

The posterior approach in THR: assuring capsular stability

Repair of the posterior capsule is advocated to reduce dislocation after total hip replacement (THR). To date, no predictable physical findings are reported in the literature to assess the capsular integrity and risk of hip dislocation after the posterior approach. The internal rotation test is performed at 4 to 6 weeks postoperatively with the hip and knee flexed at 90° while the patient is supine. The test is positive if a firm endpoint is felt with internal rotation of ≤15°. Between January 2007 and January 2008, twenty-three patients who had magnetic resonance imaging (MRI) at a mean 1.8±0.7 years after posterior-approach THR were included in this study. Magnetic resonance images were reviewed by a blinded radiologist for the integrity of the posterior capsule and quadratus, the distance between the piriformis and conjoined tendon to bone, and the amount of piriformis obturator internus atrophy. Magnetic resonance imaging results in patients with positive internal rotation tests showed an intact posterior capsule and scarring of the tendons with no severe muscle atrophy. In patients with a negative internal rotation test, MRI showed incomplete healing of the tendons and severe muscle atrophy. Sensitivity and specificity of the internal rotation test for tendon/scar healing were 100% and 93%, respectively. The internal rotation test is a simple, reproducible test that, if positive, has a high correlation with capsule/tendon healing.

Emerging ideas: soft tissue applications of radiostereometric analysis

BACKGROUND

Currently, the movement that occurs at the site of soft tissue repair cannot be measured accurately in vivo. Radiostereometric analysis (RSA) is the gold standard for measuring movement between two skeletal segments in vivo but its application to studying soft tissue migration has been limited by the unknown stability of tantalum beads in tendons and ligaments and their ability to define rigid bodies in these structures.

HYPOTHESIS

RSA can be used to accurately measure movement between two tendon segments or between a bony and a tendon segment in vivo.

METHODS OF STUDY

The stability of tantalum beads and the ability to use such beads to define rigid bodies in some soft tissues will be investigated in animal models of tendon repair. Several tantalum bead insertion techniques will be tested using in vivo RSA measurements of bead movement followed by morphologic studies of the repaired tendon and soft tissue reaction to the tantalum beads.

SIGNIFICANCE

RSA performed on tantalum beads encapsulated in muscles and tendons could be a powerful new tool to study the in vivo motion at the site of soft tissue repairs, for instance, the tendon gap formation. If RSA could be used to evaluate the efficiency of different tendon repair techniques in vivo, enhanced rehabilitation protocols could be developed and complications associated with prolonged protection or failure of repair could be reduced.

Which procedure better restores intact hip range of motion: total hip arthroplasty or resurfacing? A combined cadaveric and computer simulation study

Previous comparisons of hip range of motion (ROM) after THA and surface replacement arthroplasty (SRA) are inconclusive due to the lack of soft tissue considerations and dissimilar control groups. The normal ROMs of 8 intact cadaveric hips were determined by placing specimens in 6 discrete, predefined positions of rotation at a standard torque. In each position, the limiting factor of ROM, either bony impingement or soft tissue restriction, could be determined. Total hip arthroplasty and SRA components were virtually implanted, and ROM until impingement was determined. With a THA, the ROM was comparable to that of the intact hip. With an SRA, flexion (111° ± 13°) was less than for the intact hip (131° ± 6°). Surface replacement arthroplasty, but not THA, significantly decreases the ROM compared to intact hips.

The history of the anterior approach to the hip

The anterior approach is a safe, reliable, and feasible technique for total hip arthroplasty, permitting optimal soft tissue preservation. Since Hueter first described this interval, many surgeons have approached the hip anteriorly to perform a myriad of surgical procedures. The anterior approach allows optimal muscle preservation, and it is a truly internervous approach to the hip. An understanding of the evolution of the anterior approach to the hip will help the orthopedic community understand these advantages and why so many have used this approach in the treatment of hip pathology and for the implantation total hip arthroplasty.

MRI shows biologic restoration of posterior soft tissue repairs after THA

Although posterior capsule repair reduces the incidence of dislocation after THA, radiographic imaging studies suggest a high failure rate of the repair. Using MRI, we prospectively followed patients to evaluate the integrity of the posterior soft tissue repair after primary THA. Thirty-six patients (21 men, 15 women) underwent arthroplasty using a standard posterior approach. The posterior capsule and external rotators were repaired as separate layers using nonabsorbable sutures through two drill holes in the greater trochanter. Patients observed postoperative hip precautions for 6 weeks after surgery. All patients underwent initial MRI between postoperative Days 2 and 4. Thirty patients returned for followup MRI 3 months after surgery. At 3 months followup, the posterior capsule remained intact in 27 of 30 patients (90%) and the quadratus femoris repair remained intact in 29 of 30 patients (97%). Thirteen of 30 piriformis tendon repairs (43%) and 17 conjoined tendon repairs (57%) showed a gap between the hypointense tendon end and the greater trochanter greater than 25 mm. Our data show repaired posterior soft tissues provide a biologic scaffold allowing formation of a posterior pseudocapsule.

Modified posterior approach to total hip arthroplasty to enhance joint stability

We modified the posterior approach by preserving the external rotator muscles to enhance joint stability after primary THA. We asked whether this modified posterior approach would have a lower dislocation rate than the conventional posterior approach, with and without a repair of external rotator muscles. We retrospectively divided 557 patients (670 hips) who had undergone primary THA into three groups based on how the external rotator muscles had been treated during surgery: (1) not repaired after sectioning, (2) repaired after sectioning, or (3) not sectioned and preserved. The minimum followup was 1 year. In the group with preserved external rotator muscles, we observed no dislocations; in comparison, the dislocation rates for the repaired rotator group and the no-repair group were 3.9% and 5.3%, respectively. This modified posterior approach, which preserves the short external rotator muscles, seemed effective in preventing early dislocation after primary THA.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The unstable total hip replacement

BACKGROUND

Dislocation is one of the most common complications of total hip arthroplasty with a reported dislocation rate of 3.2%. Despite increased experience with hip replacement, the overall rate has not yet changed. The aim of this paper is to review the most recent literature published on this topic and indexed in Medline, in order to clarify the main risk factors, and to standardize a treatment protocol of such an important complication of prosthetic surgery.

MATERIALS AND METHODS

Medline database was searched using key words: "hip dislocation", "hip instability" from 1980-2007. Studies were eligible for review and included if they met the following criteria: (1) publication in English, (2) clinical trials (3) review papers.

RESULTS

The risk of first-time dislocation as a function of time after the surgery is not well understood. Most, but not all, series have demonstrated that the risk of dislocation is highest during the first few months after hip arthroplasty; however, first-time late dislocation can also occur many years after the procedure. Several risk factors were described, including the surgical approach, the diameter of the head, impingement, component malposition, insufficient abductor musculature. In addition, there are also many treatment options, such as long-term bracing after closed reduction, component reorientation, capsulorraphy, trochanteric advancement, increasing offset, exchange of the modular head and the polyethylene liner, insertion of constrained liner.

CONCLUSION

Preventing hip dislocation is obviously the best strategy. Surgeons must take into account patient and surgical risk factors. For patients at high risk for dislocation the surgeon should accurately restore leg length and femoral offset; the use of larger femoral heads, posterior transosseous repair of the capsulotendinous envelope if posterior approach is chosen or the use of a lateral approach should be considered. Proper patient education and postoperative care are very important.

Capsular-enhanced repair of the short external rotators after total hip arthroplasty

Higher dislocation rates have been reported with the posterior approach to the hip. Empirical studies suggest that careful repair of the posterior structures significantly reduces this risk. However, studies examining the integrity of repair using plain radiographs and metallic markers have reported high failure rates. To explain this discrepancy, we performed a study using radiostereometric analysis to assess the repair. Ten patients were recruited. Markers were placed into the capsule and bone. The capsule and conjoined short external rotators were repaired through drill holes in bone. At 3 months, stress radiostereometric analysis radiographs were taken in internal and external rotation. Eight of 10 patients had a mean of 3.51-mm difference in separation, suggesting that the repair was intact. We recommend careful repair of posterior structures when using the posterior approach to reduce the risk of dislocation.

Abduktorennahtversagen und Nervenschädigung beim transglutealen Zugang zur Hüfte

BACKGROUND

When used for total hip replacement, the lateral approach is associated with two frequently iatrogenic, but virtually insoluble problems: limping attributable to abductor insufficiency and pain at the greater trochanter. They can result from injury to the inferior branch of the superior gluteal nerve and/or failure of the abductor repair.

MATERIAL AND METHODS

These complications are due to the interruption of a voluminous abductor mass at the trochanter, which has to be done to allow undisturbed work on the femoral shaft and implantation of a straight femoral component while the leg is in the classic figure 4 position. When the lateral approach is used they cannot be avoided except by application of a technique that does not require the hip to be forced into flexion by the figure 4 position. This is possible with only slight detachment of anterior parts of the abductors, as described by Watson-Jones, and preparation of the femoral shaft as reported by Röttinger, with the hip in extension.

RESULTS

In comparison with the Röttinger technique, in which the surgeon manages without detaching the abductors, the technique with the slight detachment lessens the traction on the abductors and lowers the risk of nerve damage in the interval between abductor and tensor.

CONCLUSION

Whichever technique is ultimately selected, it is of decisive importance that in the case of an approach to the hip joint by way of an anterior capsulotomy with the abductors shifted in the posterior direction, the femoral shaft is prepared with the hip in extension.

Anterior capsular repair in total hip arthroplasty performed for late-presenting displaced femoral neck fractures

Dislocation after total hip arthroplasty performed for femoral neck fractures occurs frequently due to the significantly higher range of movement of the postoperative hip joint. Proper wound closure can prevent the loss of structural support provided by the capsule and myofascial structures, and is essential for postoperative hip stability. On 32 consecutive patients (four men, 28 women; mean age 64 years, range 48-83 years) with unilateral late-presenting displaced femoral neck fractures, a careful anterior capsule repair technique during total hip arthroplasty was performed by a single surgeon between 1997 and 2000. At one-year follow-up, no dislocation had occurred in any patient. Intraoperative protection and careful anatomic reattachment of the hip joint capsule may increase the stability of the hip joint after total hip arthroplasty and lead to a lower incidence of dislocation.

Minimal-invasive Hüftendoprothetik

Minimally invasive surgery aims at reducing soft tissue trauma to reduce blood loss and postoperative pain, to shorten the necessary stay in hospital, to accelerate the rehabilitation and to improve the cosmesis of the scar. The article describes the technique of minimally invasive total hip arthroplasty via an anterior approach utilizing the interval between the tensor fasciae latae, gluteus medius et minimus muscle laterally and the sartorius and rectus femoris muscle medially. The proposed method is a safe procedure, which allows correct placement of cup and stem. It may be performed within a reasonable time and blood loss is low. The procedure leads to cosmetically pleasing scars. As the patients usually do not suffer from considerable postoperative pain and experience accelerated rehabilitation, they agree to early discharge.

Integrity of repaired posterior structures after THA

Various studies have questioned the benefit of repairing the posterior structures after total hip arthroplasty because their integrity can appear disrupted at followup. However, these studies did not directly examine the posterior structures. We hypothesized that repaired posterior structures remain intact after total hip arthroplasty, and that their integrity could be evaluated by ultrasonography. We performed evaluations in the hips of 18 patients that had either the short external rotators and capsule repaired, or the capsule, short external rotators, and quadratus femoris repaired. Nine patients in each group were examined using ultrasonography at 6 weeks and 3 months postoperatively. The short external rotators and capsule were intact in 89% of patients in both groups at 6 weeks and 3 months postoperatively. At both time points, the quadratus femoris had continuity in 44% of hips with the standard posterior repair and 78% of hips with the enhanced posterior repair (p = 0.15). Ultrasonography can be used to effectively assess the integrity of the posterior repair after total hip arthroplasty. The posterior structures were intact in the majority of patients 3 months after total hip arthroplasty.

The effect of EPSTR and minimal incision surgery on dislocation after THA

Dislocation rates after posterior approach THA have decreased with the advent of enhanced posterior soft tissue (EPSTR) repairs that incorporate the external rotators. We examined three posterior approaches (simple posterior repair, EPSTR, and posterior minimal incision surgery using enhanced posterior soft tissue repair) performed by one surgeon in 390 consecutive primary THA operations (390 patients) from 1992-2003. A simple posterior repair of the external rotators done through three drill holes was performed in the first 90 patients. EPSTR incorporating the external rotators and posterior capsule in one continuous sleeve was performed in 180 patients. A 10 cm mini incision with EPSTR was performed in 120 patients. The overall dislocation rate for the series was 2.3% (9 of 390 procedures) with a 1% (4 of 390 procedures) revision rate for dislocation. The simple repair group had a greater dislocation rate (5.5%) compared to the group with EPSTR (1.3%) and the minimal incision with EPSTR group (1.7%). EPSTR decreased dislocation after total hip arthroplasty performed with a posterior approach. A 10 cm mini incision posterior approach with EPSTR maintained the low dislocation rate. Revision rate for dislocation was equivalent between the 3 groups.