Role and results of the high hip center

Morselized bone autograft for high placement of acetabular component closure with hip arthroplasty revision after 3-years screws and cup loosening: A case report

INTRODUCTION AND IMPORTANCE

Aseptic loosening in high placement of the acetabular component seriously affects the hip and femoral head loads. Surgery revision is highly recommended with defect closure in previous place.

CASE PRESENTATION

A-40-year-old man came with chief complaint of right groin pain and noticeable leg length discrepancy gait. The first hip arthroplasty through pseudo-acetabulum cup was done three years ago after neglected femoral head necrosis due to eight years of unknown hip dislocation in vehicle accident. On hip x-ray there is a screws and cup loosening, without any sign of infection from blood or from soft tissue which undergoes pathological and mold examination. The patient than assessed with periprosthetic aseptic loosening of hip dextra and simple total hip arthroplasty revision using true acetabulum location was done. The pseudo-acetabulum area closed with morselized bone autograft. One weeks after surgery, the wound healed properly. Hence, the patient sent to the rehabilitation.

CLINICAL DISCUSSION

Hip arthroplasty revision of aseptic loosening in high placement acetabular component should perform by returning to anatomical acetabular position. Cancellous morselized bone autograft (MBA) was used to closed the defect formed by previous procedure.

CONCLUSION

Revision of hip arthroplasty combined with morselized bone autograft can be considered for high placement acetabular component defect closure to provide better stability and strength in weight loads transfer.

Effect of Hip Joint Center on Multi-body Dynamics and Contact Mechanics of Hip Arthroplasty for Crowe IV Dysplasia

OBJECTIVE

To investigate the hip joint forces, Von Mises stress, contact pressure and micro-motion of hip prosthesis for developmental dysplasia of the hip (DDH) patients under different hip joint centers using musculoskeletal (MSK) multi-body dynamics and finite element analysis.

METHODS

Both MSK multi-body dynamics model and finite element (FE) model were based on CT data of a young female DDH patient with total hip replacement and were developed to study the biomechanics of the S-ROM hip prosthesis. The same offset of hip joint center along all six orientations compared with the standard position was set to predict its effects on both MSK multi-body dynamics and contact mechanics during one gait cycle.

RESULTS

The hip joint forces in the entire walking gait cycle showed two peak values and clear differences between them under different hip joint centers. The hip joint force increased when the hip joint center moved posteriorly (2101 N) and laterally (1969 N) to the anatomical center (1848 N) at the first peak by 13.7% and 6.6%, respectively. The hip joint force increased sharply when the hip center deviated laterally (2115 N) and anteriorly (2407 N), respectively, from the standard position (1742 N) at the second peak. For the sleeve of the S-ROM prosthesis, the maximum Von Mises stress and contact pressure of the sleeve increased if the hip joint center deviated from the anatomical center posteriorly at the first peak. However, the Von Mises stresses and contact pressure increased at anterior and lateral orientations, compared to that of the standard position at the second peak. Small changes were observed for the maximum relative sliding distance along most of the orientations at both peaks except in the lateral and medial orientations, in which an increase of 8.6% and a decrease of 13.6% were observed, respectively.

CONCLUSION

The hip joint center obviously influenced the hip joint forces, stress, contact pressure and micro-motion of the hip implant for this female patient.

Jumbo cup in hip joint renovation may cause the center of rotation to increase

BACKGROUND

Utilizing the large jumbo cup in revision total hip arthroplasty is an effective approach to cure many lacunar and segmental peripheral bone defects. However, with the use of the jumbo cup, the center of the hip joint may become elevated relative to the primary acetabulum, and the diameter of the large cup is greater.

AIM

To study the height and the significance of the elevation of the hip joint center.

METHODS

Eighty-eight patients matched the criteria for this condition and were included in the study. The center height of the hip joint was measured relative to the opposite normal hip joint. The diameter of the jumbo cup was measured and checked according to operation notes, and the diameter of the jumbo cup was measured with a prosthesis label. Then, the horizontal and vertical centers of rotation were measured on the surgical side and opposite side. The average center height of the hip joint on the renovated side and the opposite side and the position of the hip cup relative to the teardrop were compared using a paired t-test.

RESULTS

Radiometric analysis showed that the average hip joint center was elevated by 7.6 mm. The rotational center height delta of the renovated hip was 7.6 ± 5.6 mm, and there was an obvious difference between the two groups (P = 0.00). The difference in horizontal distance was 0.5 ± 5.1 mm (-11.5 -14.0 mm), and there was no obvious difference between the two groups (P = 0.38). According to the foreign standard, the rotational center height delta of the renovated hip was 7.5 ± 6.2 mm, and there was a significant difference between the two groups (P = 0.00). There was no obvious difference between the domestic and foreign standards (P > 0.05) between the two groups.

CONCLUSION

The application of the jumbo cup elevates the rotational center of the hip joint, but it is feasible and effective to use the jumbo cup.

[What are the benefits of patient-specific reconstruction in total hip replacement?]

BACKGROUND

The success of primary total hip replacement (THR) is predominately determined by the primary stability of the implant and the restoration of the patient-specific joint biomechanics. The three-dimensional (patho-) anatomy, size, geometry, and shape of the acetabulum and proximal femur is highly variable in patients with advanced hip osteoarthritis. Accurate preoperative planning is an essential prerequisite for all replacement procedures.

CURRENT SITUATION

Current data demonstrates clinical advantages for patient-specific reconstruction of functional joint geometry via surrogate parameters (offset and leg length). Frequently cited "target zones" for the positioning and orientation of the cup are increasingly in the focus of scientific discussion, as individually adjusted target zones for implant positioning allow for a potential reduction of impingement risk. Patients with spinal fusions or pathologic spinopelvic alignment require that particular attention be paid to patient-specific preoperative preparation, the surgical technique, and implant selection in order to reduce the risk of postoperative instability.

Primary Total Hip Arthroplasty in Severe Dysplastic Hip Osteoarthritis With a Far Proximal Cup Position

BACKGROUND

Developmental hip dysplasia is the most common cause of secondary hip osteoarthritis. Due to severe acetabular bone deficiency, cup positioning in total hip arthroplasty (THA) of dysplastic hips remains a surgical challenge. The aim was to analyze the functional outcome of far proximal cup positions in primary THA.

METHODS

Fifty patients (61 hips) with THA for severe dysplastic osteoarthritis and a far proximal cup position were included. Patients were divided according to the heights of the implanted cups with increasing vertical distance from the interteardrop line (group A: 55-65 mm, group B: 65-75 mm, group C: >75 mm). Functional outcome was assessed at latest follow-up (38 ± 16 months) by Lower Extremity Functional Score, Tegner Activity Score, and Harris Hip Score (HHS). Patients answered a Patient Satisfaction Questionnaire. Leg length discrepancy was estimated radiographically.

RESULTS

The Lower Extremity Functional Score significantly decreased in C (45.3 ± 25) compared to A (66.7 ± 15.3) and B (67.9 ± 9.9). The Tegner Activity Score significantly increased in all subgroups from preoperative to postoperative (2.2 ± 1.3 to 4.1 ± 1.4; P < .05). The mean overall HHS was 89.3 ± 14.7 (A: 89.5 ± 14.3, B: 94.3 ± 6.5, C: 78.3 ± 22.1). The HHS domains of activity of daily life and gait were significantly reduced in C (P < .05). Patients described a high satisfaction level with the surgery. No significant differences were found with regard to preoperative and postoperative leg lengthening (P = .881). Neither dislocations, impingement problems nor neurologic complications were observed.

CONCLUSION

Primary THA without any concomitant surgical interventions with a far proximal cup position offers a safe and effective treatment option in severe dysplastic hip osteoarthritis.

Use of Oversized Highly Porous Cups in Acetabular Revision

This study assessed the efficacy of highly porous cups in revision total hip arthroplasty for Paprosky types II and III acetabular bone loss. The authors identified 33 acetabular revisions in 29 patients from a prospective database (66% type III, 7 with pelvic dissociation). Initial stability was achieved with interference fit between the anterior inferior iliac spine, pubis, and ischium with cups that were 2 to 4 mm larger than the reamed acetabulum and augmented with multiple screw fixations without allograft or wedges. At mean follow-up of 6 years (range, 2.7-7.7 years) after revision surgery, no dislocation, infection, or reoperation was noted. Mean satisfaction score was 6±3.2. Mean anteversion and abduction angles were 43°±4.6° and 21.5°±4.4°, respectively. Complications included limp in 13% of patients, wound issues in 10%, and heterotopic ossification in 17%. Osteointegration was seen in all cups, without any migration. Mean overall osteointegration, based on the average percentage of the 3 zones in both views, was 55%±21% (range, 25%-95%). The most osteointegration was seen in zone I (superior) and zone VI (posterior), and the least osseointegration was seen in zone II (medial) and zone IV (anterior). This method can provide reproducible results in acetabular revision arthroplasty.

Cementless Total Hip Arthroplasty With a High Hip Center for Hartofilakidis Type B Developmental Dysplasia of the Hip: Results of Midterm Follow-Up

BACKGROUND

Acetabular reconstruction in adults with Hartofilakidis type B developmental dysplasia of the hip is a major technical challenge. The purpose of this retrospective study was to evaluate hip function and radiographic outcomes regarding high hip center at midterm follow-up.

METHODS

From January 1, 2007 to December 31, 2009, 37 patients who had Hartofilakidis type B developmental dysplasia of the hip underwent a primary total hip arthroplasty using a high hip center technique. Functional, radiographic, and survivorship outcomes were evaluated.

RESULTS

Of the 37 patients, 31 patients (83.8%) were available for the mean follow-up of 6.1 years (range, 1.5-7.6 years). Thirty-one cementless cups were located at an average vertical distance of 38.1 ± 3.3 mm and at a mean horizontal distance of 35.5 ± 3.4 mm. The mean ratio of the height of the hip center was 2.4% (range, 2.0%-2.9%). The Harris Hip Scores were improved from 50.3 points (range, 38-63 points) preoperatively to 92.3 points (range, 85-100 points) at the final follow-up (P < .001). Four patients continued to present with Trendelenburg gait pattern at the last follow-up. With use of revision for any reason and aseptic loosening as the end point, the 5-year survival rates were 90.3% (95% CI, 79.9%-100%) and 93.3% (95% CI, 84.3%-100%), respectively.

CONCLUSIONS

The high hip center technique in conjunction with a cementless acetabular component seems to be a valuable alternative to achieve satisfactory midterm outcomes for Hartofilakidis type B developmental dysplasia of the hip.

Hemispheric hydroxyapatite-coated cups with impacted graft for severe bone defects in acetabular reconstruction: ten year follow-up

Cementless acetabular reconstruction with bone grafting has been limited to moderate bone defects. We report the outcomes of 57 acetabular revisions in 45 patients with severe bone defects (Paprosky type IIIA) using hemispheric hydroxyapatite (HA)-coated cups and impacted graft. After a mean follow-up of 10 years, all but 2 cups (3.5%) remained radiologically stable. There was clear radiological consolidation and medial wall remodelling of the graft in 62% of the cases. In 2 cases (3.5%), nonprogressive lucencies were found; in 3 cases (5.3%) a medial gap of 2 mm, detected postoperatively, was progressively filled by newly formed bone during follow-up. Mean MDA score rose from 7.3 points preoperatively to 16.8 points in the last evaluation, with an excellent pain relief report. These results suggest that the combined use of HA-coated hemispheric cups with impacted graft to treat Paprosky IIIA defects provides a long-lasting stable implant, restores bone stock, and yields excellent clinical results.

Do jumbo cups cause hip center elevation in revision THA? A computer simulation

BACKGROUND

Acetabular revision THA with use of a large (jumbo) cup is an effective treatment for many cavitary and segmental peripheral bone defects. However, the jumbo cup may result in elevation of the hip center and protrusion through the anterior acetabular wall as a result of the oversized geometry of the jumbo cup compared with the physiologic acetabulum.

QUESTIONS/PURPOSES

The purpose of this computer simulation was to determine how much elevation of the hip center and anterior wall protrusion occurs in revision THA with use of a jumbo cup technique in which the inferior edge of the jumbo cup is placed at the inferior acetabular rim and the superior edge of the jumbo cup is placed against host bone at the superior margin of a posterosuperior bone defect.

METHODS

Two hundred sixty-five pelvic CT scans were analyzed by custom CT analytical software. The computer simulated oversized reaming. The vertical and anterior reamer center shifts were measured, and anterior column bone removal was determined.

RESULTS

The computer simulation demonstrated that the hip center shifted 0.27 mm superiorly and 0.02 mm anteriorly, and anterior column bone removal increased 0.86 mm for every 1-mm increase in reamer diameter.

CONCLUSIONS

Our results indicate that the jumbo cup technique results in hip center elevation despite placement of the cup adjacent to the inferior acetabulum. For a hypothetical increase from a 54-mm socket to a 72-mm socket, as one might see in the context of the revision of a failed THA, our model would predict an elevation of the hip center of approximately 5 mm and loss of approximately 15 mm of anterior column bone. This suggests that an increase in femoral head length may be needed to compensate for the hip center elevation caused by the use of a large jumbo cup in revision THA. A jumbo cup may also result in protrusion through the anterior wall.

Displacement of the hip center of rotation after arthroplasty of Crowe III and IV dysplasia: a radiological and biomechanical study

To study the direction and biomechanical consequences of hip center of rotation (HCOR) migration in Crowe type III and VI hips after total hip arthroplasty, post-operative radiographs and CT scans of several unilaterally affected hips were evaluated. Using a three-dimensional model of the human hip, the HCOR was moved in all directions, and joint reaction force (JRF) and abductor muscle force (AMF) were calculated for single-leg stance configuration. Comparing to the normal side, HCOR had displaced medially and inferiorly by an average of 23.4% and 20.8%, respectively, of the normal femoral head diameter. Significant decreases in JRF (13%) and AMF (46.13%) were observed in a presumptive case with that amount of displacement. Isolated inferior displacement had a small, increasing effect on these forces. In Crowe type III and IV hips, the HCOR migrates inferiorly and medially after THA, resulting in a decrease in JRF, AMF, and abductor muscle contraction force.

Total hip arthroplasty for adult hip dysplasia

Preoperative planning is essential to define anatomy, clarify the operative approach and exposure, and ensure that suitable implants are available.Concerns exist regarding the long-term effectiveness and safety of hip resurfacing arthroplasty for the young dysplastic hip.In light of current evidence, concerns exist regarding the use of metal-on-metal articulations for hip arthroplasty in the young dysplastic hip.The ideal bearing surface is not known, although the longest data available support the use of metal-on-polyethylene.

High hip center technique using a biconical threaded Zweymüller cup in osteoarthritis secondary to congenital hip disease

BACKGROUND

The high hip center technique used for a deficient acetabulum is reconstruction of the hip at a high center of rotation. In the literature, there is no consensus regarding the value of this technique.

QUESTIONS/PURPOSES

We investigated whether the new-generation biconical threaded Zweymüller cup fixed in a high nonanatomic position in patients with arthritis secondary to congenital hip disease experienced different rates of polyethylene wear and long-term survivorship when compared with anatomically positioned cups.

PATIENTS AND METHODS

We studied the polyethylene wear rate and Kaplan-Meier survivorship of 104 titanium threaded Zweymüller cups in 88 patients (81 females), placed in 70 hips at near-normal hip center and in 34 hips at a high hip center position at a distance of 31.1 to 60 mm (mean, 39.7 mm) from the interteardrop line. Minimum followup was 2 years (mean +/- SD, 8.6 +/- 3.5 years; range, 2-15 years).

RESULTS

The mean linear polyethylene wear rates in the near-normal and high hip center groups were not different (0.110 +/- 0.050 mm and 0.113 +/- 0.057 mm, respectively). The Kaplan-Meier 15-year cup survivorship rates with revision for any reason as an event of interest in the near-normal and high hip center groups also were not different (97.2% [95% confidence interval, 88.5%-99.3%] and 97.1% [95% confidence interval, 73.8%-99.3%], respectively).

CONCLUSIONS

The high hip center technique using a biconical threaded Zweymüller cup in patients with arthritis secondary to congenital hip disease results in a polyethylene wear rate and long-term cup survivorship comparable to those observed in anatomically positioned cups.

LEVEL OF EVIDENCE

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

Ilizarov distraction before revision hip arthroplasty after resection arthroplasty with profound limb shortening

We report the results of Ilizarov gradual distraction to regain 6.7 cm of leg length in a severely contracted hip 11 months after a resection arthroplasty. Restoration of leg length allowed revision hip arthroplasty. At 24 months after the revision arthroplasty, the patient is ambulating independently and pain free. The use of Ilizarov gradual distraction restored leg length and facilitated postoperative function.

Effect of superior placement of the hip center on abductor muscle strength in total hip arthroplasty

We evaluated 100 limbs in 50 patients who had undergone unilateral primary total hip arthroplasty with a normal contralateral hip. The 50 patients were divided into 2 groups by postoperative acetabular cup position, specifically by inferior and superior placement (inferior and superior groups). Hip abductor muscle strength was evaluated qualitatively by the modified Trendelenburg test and quantitatively by handheld dynamometer. The ratio of normalized strength of the reconstruction side to that of the nonoperated side was calculated (strength ratio). The modified Trendelenburg test was positive in 5 of 23 patients in the inferior group and 11 of 27 in the superior group (P < .05). The strength ratio of the superior group was decreased by 7.7% in comparison with that of the inferior group (P < .01).

A review of the treatment of pelvic discontinuity

Pelvic discontinuity is a complex entity with a high surgical complication rate and no standardized treatment to date. Revision hip arthroplasty in cases of massive bone loss remains a difficult and unsolved problem. The goal of the surgeon is to preserve limb function by restoring bone stock and the biomechanics of the hip. In cases of severe acetabular bone loss, biologic fixation is often inadequate, requiring extensive bone grafting and reconstructive cages. Reconstructive cages are the most commonly used devices and are designed to bridge bone defects, protect the bone graft, and reestablish the rotation center of the hip. A major limitation of current cages is that they do not allow for biologic fixation. We review the options for treating patients with massive bone loss and pelvic discontinuity and discuss therapeutic options and the clinical and radiological criteria for success.

Acetabular revision with the Contour antiprotrusio cage: 2- to 5-year followup

The Contour cage introduced in 1999 was designed to improve fixation and provide a surface for bone ongrowth. To determine whether the rates of radiographic loosening and/or revision have been reduced with the Contour design, we retrospectively reviewed the medical records and radiographs of 29 patients (average age, 68.1 years) undergoing 31 acetabular revisions with a Contour cage. The minimum followup was 24 months (mean 30 months, range, 24-58 months). Based on the Paprosky classification, two hips were Type 2B, seven were Type 3A, and 22 were Type 3B. Two hips (7%) were revised for loosening; one of these two was also infected. An additional five hips (16%) had signs of radiographic loosening. The mean Harris hip score improved from 45 to 80; functional scores improved less than the pain scores. Only 14 hips (45%) had an excellent or good clinical result and three of these 14 hips had radiographic signs of loosening; presuming these three hips eventually fail, only 35% of the hips had a good or excellent result. We found an association between number of previous surgeries and radiographic loosening and revision. Our data suggest the Contour cage offers little advantage over other antiprotrusio cages and highlight the substantial limitations of current methods available for treating patients with extensive acetabular bone loss.

Acetabular anatomy and transacetabular screw fixation at the high hip center

A quadrant system that defines the safe acetabular locations for screw placement exists for the anatomic hip center. We wanted to develop a similar system for the high hip center. The purposes of our study were to identify the anatomic structures at risk during placement of transacetabular screws in the high hip center, to identify maximum bone depth for screw purchase, and to determine if a high hip center quadrant system could be validated to guide placement of screws during acetabular arthroplasty. For this cadaver study of nine pelves, an acetabulum was reamed superiorly into the high hip center a distance equal to (1/2) of the native acetabular diameter. Screws exiting the acetabular bone by 15 mm were inserted before a computed tomography scan and a precise anatomic dissection were done. Structures at risk of penetration by screws include the external iliac vessels, the obturator nerve and vessels, the superior gluteal nerve and vessels, and the sciatic nerve. We found that a quadrant system at the high hip center can demarcate safe zones for screw placement. At the high hip center, only the peripheral (1/2) of the posterior quadrants are safe for screw placement.

Outcome of revision hip arthroplasty in patients with a previous total hip replacement for developmental dysplasia of the hip

Our aim was to determine if the height of the cup, lateralisation or the abduction angle correlated with functional outcome or survivorship in revision total hip replacement in patients with a previous diagnosis of developmental dysplasia of the hip. A retrospective investigation of 51 patients (63 hips) who had undergone revision total hip replacement was performed. The mean duration of follow-up was 119 months. Forty-one patients (52 hips) were available for both determination of functional outcome and survivorship analysis. Ten patients (11 hips) were only available for survivorship analysis.

The height of the cup was found to have a statistically significant correlation with functional outcome and a high hip centre correlated with a worse outcome score. Patients with a hip centre of less than 3.5 cm above the anatomical level had a statistically better survivorship of the cup than those with centres higher than this. Restoration of the height of the centre of the hip to as near the anatomical position as possible improved functional outcome and survivorship of the cup.

Acetabular medial wall displacement osteotomy in total hip arthroplasty: a technique to optimize the acetabular reconstruction in acetabular dysplasia

Twenty-six patients (30 hips) who had acetabular dysplasia were operated on by circumferential acetabular medial wall displacement osteotomy to reconstruct the acetabulum during total hip arthroplasty. All patients had cementless acetabular components implanted. The average acetabular component size was 50 mm (range, 44-56 mm). Only 2 hips needed structural bone graft. The mean follow-up period was 22 months (range, 6-32 months). Harris hip score had changed from 47.31 (range, 19-69 points) to 94.69 (range, 85-100 points) postoperatively (P < .01). Using the Ranawat acetabular triangle to determine the optimal hip center of rotation, the postoperative hip biomechanical environment had been improved. Our short-term follow-up suggests this technique is reliable and reproducible and generally avoids the use of bone graft and graft site morbidity. In addition, it allows the use of standard modular cementless components in patients with acetabular dysplasia.

Outcome of acetabular revision using an uncemented hydroxyapatite-coated component: two- to five-year results and review

This is a retrospective review of 50 uncemented acetabular revisions with porous, hydroxyapatite-coated cups. The acetabulum alone was revised in 22 hips and both components were revised in 28 hips. The majority of hips (26) had type 2A (Paprosky) acetabular bone loss. All the revisions were carried out through a posterior approach. The mean duration of follow-up was 32 months (range, 24-52 months). Clinically, there was significant improvement in pain and moderate improvement in movement and mobility, and there is no radiological sign of failure of any cup so far. Re-revision was performed in 3 hips (6%) for recurrent dislocation. Our early results favor the use of this type of cup in acetabular revisions with moderate bone loss, but longer-term follow-up will be required. Key words: acetabulum, hydroxyapatite, revision, bone deficiency, complications.

The high hip center

Revision of a failed acetabular component presents many challenges to the arthroplasty surgeon. The goal in most cases should be to reconstruct the acetabulum by positioning the hip center as close as possible to the anatomic hip center. However, severe acetabular bone stock deficiency and distorted acetabular anatomy often preclude placement of the acetabular component at the true anatomic hip center. In these cases, many options exist for reconstruction of the acetabulum, including placement of the cup superiorly at a high hip center. Although biomechanical studies have shown that superolateral placement of the hip center may lead to increased moments and forces across the hip (leading to potentially higher rates of loosening), superior only displacement of the hip center does not seem to adversely affect the forces about the hip. Proximal placement of the hip center facilitates contact between intact, viable host bone and the acetabular implant, thereby reducing the need for structural bone grafts, and increasing the chances for stable bony ingrowth. With proper patient selection and meticulous surgical technique, the high hip center can be a useful technique for reconstruction of the deficient acetabulum in the patient with a loose acetabular component after total hip arthroplasty.