Restoring global offset and lower limb length with a 3 offset option double-tapered stem

No differences in clinical and radiographic outcomes between standard offset and high offset short cementless stems

PURPOSE

To compare clinical and radiographic outcomes of total hip arthroplasty (THA) using standard offset versus high offset short cementless stems.

METHODS

We reviewed a consecutive series of 204 primary THAs performed over 5 years using a short cementless collared stem. At a minimum follow-up of 2 years, 6 patients had deceased, 6 were not evaluated radiographically and, 2 were lost to follow-up. This left a final cohort of 190 hips, of which 72 had received a standard offset stem and 118 had received a high offset stem. Outcomes collected included: Oxford hip score (OHS), forgotten joint score (FJS), canal fill ratio (CFR), canal-bone ratio (CBR), stem subsidence (≥ 3 mm), stem misalignment (> 5°), radiolucent lines (≥ 2 mm), cortical hypertrophy, and calcar modifications.

RESULTS

There were no significant differences in postoperative clinical and radiographic outcomes between the standard offset and high offset groups, except for incidence of stems in varus (6% vs 17%; p = 0.001). Multivariable analyses revealed that OHS was significantly worse for patients of greater age (β = 0.1; p = 0.001), higher BMI (β = 0.2; p = 0.018), or with inflammatory arthropathy (β = 4.7; p = 0.005); while FJS was significantly worse for patients with higher BMI (β = - 0.7; p = 0.003); and cortical hypertrophy was significantly associated with CBR (OR > 100; p = 0.008).

CONCLUSIONS

There were little to no differences in clinical or radiographic outcomes of THA performed using standard offset versus high offset short cementless stems. Although high offset stems are more frequently aligned in varus, while cortical hypertrophy occurs in wider intramedullary canals.

Offset restoration in total hip arthroplasty: Important: A current review

Normal vertical and horizontal offset is essential for hip biomechanics, muscle functioning and gait pattern. Total hip arthroplasty (THA) should aim to restore normal offset with implantation of femoral and acetabular components. This would be possible with proper preoperative planning, templating and ensuring implant options are available for offset restoration. Templating is essential for understanding the vertical and horizontal offset change, especially in hip arthritis presenting late with significant limb length discrepancy at THA. Planning should include appropriate soft tissue releases and the use of ideal implants to achieve restoration of horizontal and vertical offset. Under correction of horizontal offset at THA for fracture neck of femur could result in abductor fatigue, limp and increased wear. Restoration of horizontal offset is imperative at THA for a fractured neck of the femur to achieve optimal abductor function. Horizontal offset is necessary for optimal abductor muscle tension and function. Revision THA for acetabular bone loss would require hip center restoration with the acetabular and femoral offset correction to achieve limb length correction and abductor length. The inability to achieve vertical and horizontal offset correction could lead to dislocation or signs of abductor fatigue. Careful vertical and horizontal femur offset restoration is required for normal hip biomechanics, decreased wear and increased longevity.

The modern state of femoral, acetabular, and global offsets in total hip arthroplasty: a narrative review

Offsets in the frontal plane are important for hip function. Research on total hip arthroplasty (THA) surgery agrees that increasing femoral offset up to 5 mm could improve functional outcome measures. The literature indicates that global offset is a key parameter that physicians should restore within 5 mm during surgery and avoid decreasing. Substantiated findings on acetabular offset are lacking despite its recognized importance, and the medialization approach must be assessed in light of its shortcomings. Future research, possibly through improved measurement, unified definitions, patient-specific surgical planning, and technology-enhanced surgical control, with specific focus on acetabular offset, is needed to better understand its impact on THA outcomes.

Clinical Outcomes for Total Hip Arthroplasty with and without Previous Curved Periacetabular Osteotomy

There are currently no reports on the clinical outcomes after total hip arthroplasty (THA) with previous curved periacetabular osteotomy (CPO), although the outcomes after THA with non-CPO types of periacetabular osteotomy have been reported. This study aimed to clarify the differences in clinical outcomes and radiographic features after THA with or without previous CPO. We performed a retrospective case-control with individual matching study. The participants were 10 patients with 11 hips that underwent cementless THA between October 1998 and October 2018 with previous CPO (osteotomy group). For the control group, we matched age, sex, and follow-up period, and included 32 patients with 33 hips that underwent cementless THA without previous CPO at a 1:3 ratio. The Harris Hip Score (HHS), cup size, position, and alignment, global offset (GO), operative time, perioperative blood loss, frequency of osteophyte removal, and major complications were compared between the two groups. The osteotomy group had no cases with revision surgery and dislocation. No significant differences were found between the two groups as follows: mean HHS, 94.9 points in the osteotomy group versus 92.7 points in the control group at the final follow-up; mean GO, 70.1 mm in the osteotomy group versus 71.4 mm in the control group; cup size, position, and alignment after THA; operative time; and perioperative blood loss. The frequency of osteophyte removal was higher in the osteotomy group. The take-home messages were that the clinical outcomes, including HHS, and radiographic features, including GO, after THA were equivalent in the two groups.

Radiographic results on acetabular cup placement with the SuperPath technique: a retrospective study of 756 cases

Background

The Supercapsular percutaneously assisted total hip (SuperPath) technique is a relatively new minimally invasive approach for total hip arthroplasty (THA). Good clinical outcomes related to its use are reported in the literature. Nonetheless, there are still uncertainties about its validity in terms of radiographic outcomes.

Main purpose of the study is to evaluate the effectiveness of the SuperPath in acetabular cup positioning through radiographic evaluation of acetabular inclination angle (IA) and acetabular anteversion (AA) angle within the safe zone described by Lewinnek. The leg length discrepancy (LLD), femoral offset (FO), and acetabular offset (AO) were also measured to ascertain the radiographic effectiveness of SuperPath in the acetabular cup placement.

Methods

Between January 2016 and December 2019, all SuperPath cases eligible for the study were included. They were operated by three orthopaedic surgeons with long-standing experience in THA via conventional posterolateral approach and who have performed SuperPath training fellowship. The Mann-Whitney U test was used for statistical assessments (p-value < 0.05). Means ± standard deviation (SD) of the radiographic IA and AA were calculated for each year.

Results

A retrospective analysis of 756 THAs was performed. The average percentage of IA within the Lewinnek’s safe zone was from 80 to 85%, while the average percentage of AA was from 76 to 79%. Both IA and AA showed no statistically significant difference between two consecutive years. Good results, in the ranges of normal values, were also obtained for LLD, FO and AO, with homogeneous outcomes between 1 year and the following one.

Conclusion

It is possible to achieve good radiographic values of acetabular cup orientation through the SuperPath within the Lewinnek’s safe zone. These results are similar to those reported in the literature by authors using SuperPath. Low rate (0,3%) of hip dislocations were reported. Therefore, the SuperPath technique represents a good alternative THA approach. Nevertheless, there is not a statistically significant improvement in these radiographic parameters over a four-year time.

Level of evidence

Level IV, retrospective study.

Clinical and radiological results of high offset tri-lock bone preservation stem in unilateral primary total hip arthroplasty at a minimum follow-up of 3 years

Background

Although the high offset Tri-Lock bone preservation stem (BPS) was used widely, few studies explored the clinical and radiological results. The purpose of this study was to determine the clinical and radiological results of high offset Tri-Lock BPS in unilateral primary total hip arthroplasty (THA) at a minimum follow-up of 3 years.

Methods

55 patients who underwent cementless THA with high offset Tri-lock BPS from 2017 to 2018 were followed for a minimum follow-up of 3 years. Patients were assessed clinically for complications, Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Oxford Hip Score (OHS). Femoral offset (FO), acetabular offset (AO), hip offset (HO), HO difference, and leg length discrepancy (LLD) were measured on the anteroposterior (AP) pelvic radiograph. Standard pelvic AP and lateral radiographs were used to evaluate for evidence of bone ingrowth, stem subsidence, stem alignment, radiolucent line around the stem, osteolysis, loosening, ectopic ossification, and femoral stress shielding.

Results

No patients reported complications during hospitalization nor the follow-up period. At a mean follow-up of 42.5 months, the mean HHS, WOMAC, and OHS scores showed a significant improvement from preoperative to the latest follow-up. No patients reported thigh pain. No revision nor sign of radiographic loosening had been detected. The high offset Tri-Lock BPS significantly improved the FO and HO postoperatively. HO difference and LLD were balanced postoperatively. No sign of stem subsidence, radiolucent line, osteolysis, loosening, ectopic ossification, nor severe stress shielding (more than grade 3–4) were observed at the latest follow-up.

Conclusion

The high offset Tri-Lock BPS demonstrated excellent clinical and radiographic outcomes at a minimum follow-up of 3 years. HO difference and LLD between legs decreased significantly and achieved balance postoperatively. Long-term follow-up is required for a definitive conclusion.