Distal femoral shortening osteotomy for treatment of sciatic nerve palsy after total hip arthroplasty - a report of 3 cases

Leg Length Discrepancy in Total Hip Arthroplasty: Not All Discrepancies Are Created Equal

The original review article, published in 2006, describing leg length discrepancy after total hip arthroplasty commented that "equal leg length should not be guaranteed." There has been considerable advancement in surgical technique and technology over the past decade, allowing surgeons to "hit the target" much more consistently. In this interval paper, we review leg length discrepancy and introduce some technologies designed to mitigate this complication. In addition, we present challenging clinical scenarios in which perceived leg length may differ from true leg length and how these can be addressed with proper workup and surgical execution.

Total hip arthroplasty with monobloc press-fit acetabular components and large-diameter bearings for atypical acetabula is safe: a consecutive case series of 125 hips with mean follow-up of 9 years

BACKGROUND

Large-diameter head (LDH) total hip arthroplasty (THA) with a monobloc acetabular component improves hip stability. However, obtaining initial press-fit stability is quite challenging in atypical acetabula. The purpose of this study was to assess primary and secondary fixation of monobloc cups in atypical acetabula.

METHODS

In this consecutive case series, the local arthroplasty database was used to retrospectively identify patients with secondary osteoarthritis who underwent primary hip replacement with press-fit only LDH monobloc acetabular components between 2005 and 2018 and who had a minimum of 2 years of follow-up. Radiographic evaluation was performed at last follow-up, and patient-reported outcome measures (PROMs) were assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Forgotten Joint Score (FJS), and the Patient's Joint Perception (PJP) question.

RESULTS

One hundred and six LDH THAs and 19 hip resurfacings were included in the study. Preoperative diagnoses included hip dysplasia (36.8%), Legg-Calve-Perthes disease (32.0%), osteoarthritis with acetabular deficiency (17.6%), periacetabular osteotomy (8.0%), arthrodesis (4.0%), and osteopetrosis (1.6%). After a mean follow-up of 9.2 years, no aseptic loosening of the acetabular component was recorded nor observed on radiologic review. There were 13 (10.4%) revisions unrelated to the acetabular component fixation. The mean WOMAC and FJS scores were 9.2 and 80.9, respectively. In response to the PJP question, 49.4% of the patients perceived their hip as natural, 19.1% as an artificial joint with no restriction, 31.5% as an artificial joint with restriction, and none as a non-functional joint.

CONCLUSION

Primary press-fit fixation of monobloc acetabular components with LDH implanted in atypical acetabula led to secondary fixation in all cases with low revision and complication rates and great functional outcomes. With careful surgical technique and experience, systematic use of supplemental screw fixation is not essential in THA with atypical acetabula.

Midterm results of titanium conical Wagner stem with challenging femoral anatomy: Survivorship and unique bone remodeling

BACKGROUND

Complex anatomy of the proximal femur makes total hip arthroplasty (THA) more challenging. Short, straight, fluted and conical titanium stem like the Wagner Cone can be helpful to address small femoral canal, increased femoral neck version, important leg length discrepancy or proximal femoral deformity. The outcome in these patients is less assured and associated with high rate of complications. Therefore, we did a retrospective study aiming to answer: 1) can the Wagner Cone stem provide acceptable mid- to long-term implant survivorship; 2) help minimizing perioperative adverse events; 3) produce favorable clinical outcome measured by WOMAC score; and 4) be associated with a favorable radiographic femoral bone remodeling at the last follow-up?

HYPOTHESIS

Wagner Cone stem is an advantageous solution for the distorted proximal femur in complex THA.

PATIENTS AND METHOD

Our cohort was derived from the patient registries where medical records of 88 patients (103 hips) who underwent primary THA using the Wagner prosthesis were retrospectively reviewed. Then, data was analyzed for patients' demographics and surgical data, and comparing preoperative, immediate postoperative and last follow-up data. Eleven patients (12 hips) were excluded (7 hips followed up less than 2 years or lost to follow-up, 3 hips that had the Wagner stem for revision and 2 Wagner stems inserted for periprosthetic fracture). This left 77 patients (91 hips) with Wagner cone stems implanted for more than 2 years between March 2003 and February 2017 by 7 surgeons in 3 academic hospitals. Implant revision, reoperations, WOMAC score and radiographic analyses were recorded at last follow-up.

RESULTS

After a mean follow-up of 7.8 (range, 2.0-16.2) years, Wagner stem survivorship was 98.9% (95% CI: 94 to 100%) with one (1.1%) stem revision for failure of osteointegration. Five (5.5%) acetabular revisions, one for aseptic loosening, 2 for adverse reaction to metal debris and 2 for infection. One (1.1%) sciatic neuropathy and 4 (4.4%) intraoperative fractures were encountered. The mean WOMAC score was 90.5±11.4 (59-100). Radiographic analysis showed clear signs of stem osseointegration and hypertrophic bone remodeling in 82 cases (92.1%).

CONCLUSIONS

Used in complex cases with proximal distorted femurs, the Wagner Cone stem demonstrated a low complication rate, a high-rate consistent adaptive bone remodeling, excellent clinical results, and midterm survival. It is a safe, reliable and advantageous option in complex primary THA. However, the contribution of the underlying cause of the secondary osteoarthritis on the long-term survival of the stem remains to be demonstrated.

LEVEL OF EVIDENCE

IV; retrospective study.

Short stature and short distance between the anterior acetabular rim to the femoral nerve are risk factors for femoral nerve palsy following primary total hip arthroplasty using the modified Watson-Jones approach

BACKGROUND

Nerve palsy following total hip arthroplasty (THA) critically impacts patient clinical function. However, few studies have focused on femoral nerve palsy (FNP) following THA via the modified Watson-Jones approach. Previous reports have suggested that THA, regardless of the approach, is associated with several FNP risk factors, including female gender, hip dysplasia, revision surgery, and short stature. Magnetic resonance imaging (MRI) has suggested that a shorter distance between the femoral nerve and the anterior acetabular edge (dFN) is related to FNP after THA. The purposes of this study were: 1) to determine the presumed risk factors through a retrospective investigation of FNP clinical courses, and 2) to identify the relationships between FNP occurrence and the short dFN following primary THA via the modified Watson-Jones approach.

HYPOTHESIS

Short stature is a risk factor for femoral nerve palsy following THA. i.e. a significant difference in dFN exists between patients with and without FNP.

PATIENTS AND METHODS

This retrospective case-control study was performed at a single university hospital. From January 2016 to December 2020, 676 THAs were performed via the modified Watson-Jones approach at our institution. These included 495 THAs performed in the supine position and 181 in the lateral position. In this study, FNP was defined as weakness of the quadriceps femoris (manual muscle test<grade 3) with or without sensory disturbance over the anteromedial aspect of the thigh. The incidence of FNP was calculated. Patient background factors (age, sex, preoperative diagnosis, surgical position, height, weight, body mass index, surgeon experience, type of components, the method of anesthesia, leg lengthening during the surgery, and operation time) were compared between the FNP group and a non-FNP control group. The dFN was measured in T1-weighted MRI axial images at the level of the hip center. The distance between the femoral nerve and the anterior acetabular edges, where retractors are commonly placed during surgery, was also measured and compared between the FNP group and the non-FNP control group. The FNP group and non-FNP control group were extracted by 1:4 matching of patient height and weight. All data were statistically evaluated using the Mann-Whitney U test, and p values less than 0.05 were considered statistically significant.

RESULTS

FNP occurred in 6 out of 676 joints (0.88%) following primary THA via the modified Watson-Jones approach. In all 6 cases, the motor deficit recovered completely within a year. Patient height was significantly shorter in the FNP group than in the non-FNP control group (148.4±3.3cm vs. 155.4±8.1cm [p=0.01]). The dFN was significantly shorter in the FNP group (16.3±4.1mm vs. 21.5±4.0mm [p=0.034]).

CONCLUSION

Short stature and short dFN are risk factors for FNP after THA using the modified Watson-Jones approach.

LEVEL OF EVIDENCE

III, case-control study.