Oversized acetabular socket causing groin pain after total hip arthroplasty

Downsizing and minimising medialisation of the acetabular component: Novel technique to preserve bone in THA

Standard practice for acetabular component placement in total hip arthroplasty (THA) is to medialise the acetabular component. Bone preservation techniques during primary THA are beneficial for possible future revisions. The goal of this study is to examine the effect of downsizing and minimising medialisation of the acetabular component on bone resection volume. The volume of bone resected during acetabular preparation for different sizes of components was calculated and the volume of bone preserved by downsizing the cup was determined. Minimising medialisation of the acetabular component by 1-3 mm from the true floor was calculated. Absolute values and percentage of bone volume preserved when acetabular components are downsized or less medialised is presented. Downsizing the acetabular component by one size (2 mm) preserves between 2.6 cm³ (size 40 vs 42) and 8.4 cm³ (size 72 vs 74) of bone volume and consistently reduces resected bone volume by at least 35% (range 35.2%-37.5%). Similarly, reducing medialisation of a 56 mm acetabular cup (as an example of a commonly implanted component) by 3 mm reduces bone loss by 5.9 cm³- 44% less bone volume resection. Downsizing and minimising medialisation of the cup in THA substantially preserves bone which may benefit future revision surgeries. Surgeons could consider implanting the smallest acceptable acetabular shell to preserve bone without compromising on head size.

Arthroscopic iliopsoas tenotomies: a systematic review of surgical technique and outcomes

PURPOSE

To evaluate the technique, results and complications of arthroscopic iliopsoas tenotomies either on native hips or total hip arthroplasty (THA).

METHODS

A systematic review was performed using 3 databases: PubMed, EMBASE and the Cochrane library from January 2000 to December 2018 in accordance with the PRISMA procedure. The literature search, data extraction and quality assessment were conducted by 2 independent reviewers. Surgical technique, clinical outcomes, recurrences and complication rate were evaluated.

RESULTS

Out of 115 articles reviewed, 20 articles concerned native hips and 8 articles THA. 3 levels of release were described. For native hips, the recurrence rate was higher for central compartment than peripheral or lesser trochanter releases. Complication rates were similar for hip arthroscopy but remained low in all series. Loss of strength was evaluated mainly using the MRC muscle scale. Most studies noted strength recovery. MRI analysis of muscle atrophy was greater for lesser trochanter than for central compartment release but unrelated to loss of strength. The complication rate was low for tenotomy after THA, heterotopic ossification being the most common complication.

CONCLUSIONS

Central compartment releases lead to the highest rate of recurrence due to incomplete release. Peripheral releases have a potential risk of vascular injury. The lesser trochanteric approach has the disadvantage of not having direct access to the joint. The main difficulty with THA lies in the diagnosis of cup/iliopsoas impingement. Diagnostic tests with infiltration should be made before iliopsoas release to prevent its failure. Cup protrusion of over 8mm is a potential indication for acetabular revision.

Dislocation after total hip arthroplasty: does head size really matter?

INTRODUCTION

Recent advances in polyethylene and ceramic technologies has allowed us to use larger sized heads without compromising the wear properties of a total hip arthroplasty (THA). 1 benefit of this change has been proposed to be a lower incidence of dislocation.

METHODS

We retrospectively evaluated the dislocation rate in 913 THAs performed using the same standardised surgical technique employed by a single team of surgeons at our institution between 1995 and 2015. Patients were assigned to 2 groups: small (⩽28 mm), large diameter heads (⩾36 mm and larger). The cup position was measured and plotted to determine its status according to the Lewinnek's safe zone (15° ± 10° for anteversion, 40° ± 10° for inclination).

RESULTS

16 of the 472 small heads dislocated (3.4%) while 5 of the 441 in large head group (1.1%) (p = 0.04). In all of the large head patients that dislocated the cup position was in the safe range of Lewinnek. However, in the large head group only 64.5% of the cups were in the safe zone.

CONCLUSIONS

By changing the head size to 36 mm, we were able to decrease the dislocation rate significantly. Errors of cup positioning according to Lewinnek became oblivious when using large heads. In our opinion, using large heads in THA makes a difference in terms of dislocation.

Dual Mobility Total Hip Arthroplasty Is Not Associated with a Greater Incidence of Groin Pain in Comparison with Conventional Total Hip Arthroplasty and Hip Resurfacing:A Retrospective Comparative Study

BACKGROUND

Groin pain is a common long-term complication of total hip arthroplasty (THA). Femoral head size has been proposed as one of the primary causes. The implants used in dual mobility (DM) THA have large outer-bearing articulations, which could increase the risk of post-operative groin pain. Hip resurfacing (HR), too, has been shown to be associated with a risk of groin pain.

QUESTIONS/PURPOSES

The goals of this study were to compare the incidence of groin pain at 1 year after hip arthroplasty in patients with different femoral head diameters and in patients undergoing conventional THA, DM THA, and HR.

METHODS

After combing an institutional registry for all patients who had undergone THA or HR for primary hip osteoarthritis, we included 3193 patients in the analysis; 2008 underwent conventional THA, 416 underwent DM THA, and 769 underwent HR. We used logistic regression modeling to analyze the relation of groin pain at 1 year after surgery to patient demographics and clinical characteristics, including age, sex, body mass index (BMI), University of California at Los Angeles activity score at 1 year after surgery, bearing couple, and the ratio of acetabular diameter to femoral head diameter. We also measured cup inclination and anteversion in a subset of patients with and without groin pain at 1 year to assess whether pain could be related to implant position.

RESULTS

Overall, 8.7% of patients reported groin pain at 1 year. Patients with groin pain were younger and had lower BMIs. There were increased odds of groin pain with a greater cup-to-head ratio, although DM implants, interestingly, were not significantly associated with groin pain; this may be attributable to so much of their movement taking place inside the implant. Subgroup analysis measuring cup inclination and anteversion showed no difference in cup position between patients with and without pain.

CONCLUSION

In this population of hip arthroplasty patients, the incidence of groin pain 1 year after surgery did not differ among patients undergoing DM and conventional THA; DM THA in particular was not associated with a higher risk of groin pain, despite its comparatively larger femoral head sizes. HR, on the other hand, was associated with a higher risk of pain. Appropriate implant sizing and bearing couple choice may optimize the functional benefit of THA.

The effect of cup medialization and lateralization on hip range of motion in total hip arthroplasty

BACKGROUND

There is little description of the effect of cup position on the hip range of motion in total hip arthroplasty. The purpose is to evaluate the effect of cup medialization/lateralization with a compensatory increase/decrease in femoral offset on the hip range of motion, and whether the bone morphology of the anterior inferior iliac spine affects hip range of motion in total hip arthroplasty.

METHODS

Using the CT data of 100 patients (male; 30, female; 70), 3D-dynamic motion analysis was performed in four scenarios with cup medialization/lateralization with the same/decreased global offset. We calculated the range of motion before component impingement and bony impingement in flexion, internal rotation and external rotation using the software. Furthermore, we measured bony morphological features of anterior inferior iliac spine, and we analyzed the correlations among them.

FINDINGS

We found that the cup medialization with the same stem offset had negative effects on hip range of motion in flexion and internal rotation due to bony impingement, whereas cup medialization caused external rotation to significantly decrease with the same global offset. On the other hand, cup lateralization with the same global offset had negative effects on flexion and internal rotation, whereas external rotation increased. Furthermore, there were negative correlations among flexion and laterally large and steep anterior inferior iliac spine.

INTERPRETATION

Our results demonstrated that the advantage of cup medialization can depend on the individual anatomy such as bony morphology of anterior inferior iliac spine in flexion.

The role of arthroscopy in the treatment of groin pain after total hip arthroplasty: our experience

AIM

The purpose of the study was to present our arthroscopic surgical technique and the results in patient with pain after a hip replacement.

METHODS

Between November 2009 and September 2011, 35 patients with groin pain after total hip arthroplasty (THA) were treated arthroscopically. The patients underwent a preoperative examination consisting in careful history, physical examination, laboratory evaluation, diagnostic evaluation using x-rays and pelvis CT scans. In patients for whom the clinical picture suggested iliopsoas tendonitis, we also performed injection of local anaesthetic on the iliopsoas tendon sheath. All the patients were positioned in the supine decubitus position with traction applied, using 2 arthroscopic portals (AL, MID-A). An extensive debridement of adhesions, periprosthetic tissue and neocapsula were performed; when there were signs of iliopsoas impingement, a transcapsular tenotomy was performed according to Wettstein technique.

RESULTS

The average age was 57 (29-77) years old. The average time to onset of symptoms was 10.8 (5-15) months after THA. The average preoperative Harris Hip Score (HHS) was 44.1 (range 32-56). The average preoperative Medical Research Council (MRC) scale for muscle strenght was 3.27 (range 3-4). After 24 months of follow-up patients show an average HHS of 75.73 (range 50-91). Patients who underwent iliopsoas release show a postoperative HHS of 83.28 (range 61-91). The average postoperative MRC scale was 4.45.

CONCLUSIONS

Hip arthroscopy in treatment of reactive synovitis and adhesions shows good results according to literature. Hip arthroscopy in treatment of anterior iliopsoas impingement is the most useful instrument, being less invasive than the classic open technique.

Comparison of Head Center Position and Screw Fixation Options Between a Jumbo Cup and an Offset Center of Rotation Cup in Revision Total Hip Arthroplasty: A Computer Simulation Study

Jumbo acetabular cups are commonly used in revision total hip arthroplasty (THA). A straightforward reaming technique is used which is similar to primary THA. However, jumbo cups may also be associated with hip center elevation, limited screw fixation options, and anterior soft tissue impingement. A partially truncated hemispherical shell was designed with an offset center of rotation, thick superior rim, and beveled anterior and superior rims as an alternative to a conventional jumbo cup. A three dimensional computer simulation was used to assess head center position and safe screw trajectories. Results of this in vitro study indicate that a modified hemispherical implant geometry can reduce head center elevation while permitting favorable screw fixation trajectories into the pelvis in comparison to a conventional jumbo cup.

Femoral head diameter considerations for primary total hip arthroplasty

The configuration of total hip arthroplasty (THA) implants has constantly evolved since they were first introduced. One of the key components of THA design is the diameter of the prosthetic femoral head. It has been well established that the risk of dislocation is lower as the head diameter increases. But head diameter impacts other variables beyond joint stability: wear, cam-type impingement, range of motion, restoration of biomechanics, proprioception and groin pain. The introduction of highly cross-linked polyethylene and hard-on-hard bearings has allowed surgeons to implant large-diameter heads that almost completely eliminate the risk of dislocation. But as a result, cup liners have become thinner. With femoral head diameters up to 36 mm, the improvement in joint range of motion, delay in cam-type impingement and reduction in dislocation risk have been clearly demonstrated. Conversely, large-diameter heads do not provide any additional improvements. If an "ecologically sound" approach to hip replacement is embraced (e.g. keeping the native femoral head diameter), hip resurfacing with a metal-on-metal bearing must be carried out. The reliability of large-diameter femoral heads in the longer term is questionable. Large-diameter ceramic-on-ceramic bearings may be plagued by the same problems as metal-on-metal bearings: groin pain, squeaking, increased stiffness, irregular lubrication, acetabular loosening and notable friction at the Morse taper. These possibilities require us to be extra careful when using femoral heads with a diameter greater than 36 mm.

Correlation between groin pain and cup design of hip-resurfacing implants: a prospective study

PURPOSE

Cup design has been incriminated as the source of groin pain after hip resurfacing but has not been well described; thus, it was assessed in a prospective study looking at three implant types.

METHODS

A group-match was done between three groups of hip resurfacing devices according to age, sex, body mass index, activity level, osteoarthritis aetiology and pre-operative scores.

RESULTS

The global groin pain rate was 5.7 % at six months and 2.7 % at last follow-up. Groin pain rate was significantly different between the three groups (p = 0.004) and had a strong influence on the subjective results (p = 0.04). No groin pain emerged between six months and last follow-up. No clinical differences were noted in Harris hip score and Merle d'Aubigné-Postel score at last follow-up. However, the Oxford hip score and Devane activity score were significantly lower for cups with macrostructures.

CONCLUSION

The low groin pain rate in this prospective cohort was probably secondary to the specific surgical technique used and seems to be correlated with cup design. Macrostructures on the external part of the cup could be significantly harmful.

Groin pain after replacement of the hip

Persistent groin pain after seemingly successful total hip replacement (THR) appears to have become more common. Recent studies have indicated a high incidence after metal-on-polyethylene and metal-on-metal conventional THR and it has been documented in up to 18% of patients after metal-on-metal resurfacing. There are many causes, including acetabular loosening, stress fracture, and iliopsoas tendonitis and impingement. The evaluation of this problem requires a careful history and examination, plain radiographs and an algorithmic approach to special diagnostic imaging and tests. Non-operative treatment is not usually successful. Specific operative treatment depending on the cause of the pain usually involves revision of the acetabular component, iliopsoas tenotomy or other procedures, and is usually successful. Here, an appropriate algorithm is described.