Leg length and total hip arthroplasty: old problem, new standards?

Do Cementless Stems Match Any Hip? A Description of Anthropometric Measurements of the Proximal Femur in Colombia

Background

Leg length discrepancy following hip arthroplasty causes dissatisfaction to the patient; thus, preoperative planning and implant selection is critical. The purpose of this study was to measure the articular-trochanteric distance (ATD) and femoral neck length (FNL) in our population and compare them to those of 3 of the most used uncemented stems.

Methods

In this cross-sectional study, 401 hip radiographs of healthy adults were collected between January and July 2022. The vertical ATD and FNL were measured. A linear regression model was used to identify the relationship between these measurements and age, sex, and height. A logistic regression model was used to assess the matching of native hips with the neck length of the stem.

Results

Mean age was 60 years, and 74.56% were women. In 94.3% of hips, the ATD was negative, 3.73% neutral, and 2% positive. In our population, 0.25% of FNL were shorter than POLARSTEM (Smith & Nephew, UK), 10.72% shorter than MetaFix stem (Corin, UK), and 11.97% shorter than Corail stem (DePuy Synthes, USA). In the logistic regression analysis, matching for the POLARSTEM was associated with age but not with sex or height. Conversely, for MetaFix and Corail, stem matching was associated with sex and height.

Conclusions

Anthropometric hip measurements vary among individuals, and variables such as age, sex, and height must be considered during preoperative planning and implant selection to avoid leg length discrepancy. Additional studies, including different implants, are required to guide surgeons in selecting a femoral stem that best matches the patient's native hip.

Peripheral Nerve Blockade in Total Hip Arthroplasty: A Retrospective Study with Propensity Score Matching

The effect of peripheral nerve block (PNB) according to leg lengthening following total hip arthroplasty (THA) has not been studied yet. The purpose of this study was to investigate the effect of PNB according to the change in leg length after THA. From January 2016 to August 2021, 353 patients who underwent unilateral THA for osteonecrosis of the femoral head or osteoarthritis of the hip joint were retrospectively reviewed. The patients were divided into two groups for comparison: 217 patients who controlled postoperative pain using only intravenous venous patient-controlled analgesia (IV PCA) (PCA group) and 136 patients who controlled postoperative pain using PNB and IV PCA (PCA + PNB group). We further divided the patients into two groups (leg lengthening after surgery < 10 mm and >10 mm) and compared them. After propensity score matching, the PCA and PCA + PNB groups, with 134 patients each, were compared and analyzed. The pain intensity at rest was significantly lower in the PCA + PNB group compared with that in the PCA group at postoperative 6, 24, and 48 h (p = 0.0001, 0.0009, and <0.0001, respectively). In the subgroup analysis, for patients whose limb lengthening was less than 10 mm after THA, the pain intensity at rest was significantly lower in the PCA + PNB group compared with that in the PCA group at postoperative 24 and 48 h (p = 0.0165 and 0.0015, respectively). However, in patients whose limb lengthening was more than 10 mm after THA, there was no significant difference between the pain intensity at activity and rest in the two groups at postoperative 6, 24, and 48 h (p > 0.05). PNB did not show superiority in terms of pain reduction in patients whose limb lengthening was more than 10 mm after THA. Further investigations on methods for reducing pain in patients whose leg length is increased by more than 10 mm are needed.

Managing early complications in total hip arthroplasty: the safety of immediate revision

PURPOSE

Immediate revision refers to a reoperation that involves resetting, draping, and exchanging the implant, after wound closure in total hip arthroplasty. The purpose of this study is to investigate the impact of immediate revision after total hip arthroplasty on subsequent infection and complication rates.

METHODS

A total of 14,076 primary total hip arthroplasties performed between 2010 and 2020 were identified in our institutional database, of which 42 underwent immediate revision. Infection rates were determined 2 years after the index arthroplasty. The cause and type of revision, duration of primary and revision surgeries, National Nosocomial Infections Surveillance score, implant type, changes in implants, complications, and preoperative and intraoperative antibiotic prophylaxis were all determined.

RESULTS

No infections were observed within 2 years after the index arthroplasty. Leg length discrepancy (88%, n = 37) and dislocation (7.1%, n = 3) were the main causes of immediate revision. In most cases of discrepancy, the limb was clinically and radiologically longer before the immediate revision. The mean operative time was 48 ± 14 min for the primary procedure and 23.6 ± 9 min for the revision. The time between the first incision and last skin closure ranged from 1 to 3 h. None of the patients were extubated between the two procedures. Two patients had a National Nosocomial Infections Surveillance score of 2, 13 had a score of 1, and 27 had a score of 0.

CONCLUSION

Immediate revision is safe for correcting clinical and radiological abnormalities, and may not be associated with increased complication or infection rates.

STUDY DESIGN

Retrospective cohort study; level of evidence, 3.

Robotic-assisted versus manual total hip arthroplasty in obese patients: a retrospective case-control study

Aims

The objective of this study was to evaluate the accuracy of acetabular cup positioning in the obese patients when using robotic-assisted technology during total hip arthroplasty (THA).

Methods

Data were retrospectively collected from patients who underwent primary (THA) with a body mass index (BMI) ≥ 28 kg/m² and ≥ 1 year of follow-up between January 2018 and December 2019. Their demographics, diagnosis, acetabular cup positioning, American Society of Anesthesiologists (ASA) score, Harris Hip Score (HHS), and Forgotten Joint Score (FJS) at the final follow-up were recorded for analysis.

Results

There were no statistically significant differences between the two groups in height, weight, BMI, ASA score, or preoperative Harris Hip Score (HHS). Also, there was no difference in inclination angle between the two groups (R-THA: 41.29° ± 3.04°; manual THA (M-THA): 40.47° ± 5.46°; P = 0.312). However, the mean anteversion angle was greater in the R-THA group (20.71° ± 1.98° vs. 19.08° ± 4.04°; P < 0.001). Compared to M-THA, R-THA more frequently achieved an acetabular cup angle within 5° of the target (anteversion, 98.1% vs. 78.1% P = 0.001; inclination, 88.5% vs. 53.1%, P < 0.001). The R-THA group was more advantageous in restoring the hip center of rotation (COR) and leg length difference (LLD). There was no statistical difference in postoperative HHS (P = 0.404) or FJS (P = 0.497) between the two groups.

Conclusions

Compared to manual technique, robotic-assisted technique provided more precise acetabular cup positioning and better leg length restoration for obese patients. The robotic-assisted technique was more advantageous in recovering the center of rotation position and achieved a higher proportion of the acetabular cup placed in the target safety zone. Further studies are needed to confirm the clinical outcomes of surgeries in obese patients using robotic-assisted technology.