Soft tissue restricts impingement-free mobility in total hip arthroplasty

Evaluating computed bony range of motion (BROM) by registering in-vitro cadaver-based functional range of motion (FROM) to a hip motion simulation

BACKGROUND

While modern hip replacement planning relies on hip motion simulation (HMS), it lacks the capability to include soft-tissues and ligaments restraints on computed bony range of motion (BROM), often leading to an overestimation of the in-vivo functional range of motion (FROM). Furthermore, there is a lack of literature on BROM assessment in relation to FROM. Therefore, the study aimed to assess computed BROM using in-vitro cadaver-derived FROM measurements, registered to a CT-based in-house HMS, and to further investigate the effect of functional and anatomical hip joint centres (FHJC and AHJC) on BROM.

METHOD

Seven limiting and three non-limiting circumducted passive FROM of four cadaver hips were measured using optical coordinate measuring machine with reference spheres (RSs) affixed to the pelvis and the femur, following CT-scan of the specimen. The RSs' centres were used to register the measured FROM in HMS, enabling its virtual recreation to compute corresponding BROM by detecting nearest bony impingement. FHJC, estimated from non-limiting FROM, was compared with AHJC to examine their positional differences and effect on BROM.

RESULTS

Differences in BROM and FROM were minimal in deep flexion (3.0° ± 4.1°) and maximum internal rotation (IR) at deep flexion (3.0° ± 2.9°), but substantially greater in extension (53.2° ± 9.5°). Bony impingement was observed during flexion, and IR at deep flexion for two hips. The average positional difference between FHJC and AHJC was 3.1 ± 1.2 mm, resulting in BROM differences of 1°-13° across four motions.

CONCLUSIONS

The study provided greater insight into the applicability and reliability of computed BROM in pre-surgical planning.

Direct Anterior Approach Provides Superior Prosthesis Adaptability in the Early Postoperative Period of Total Hip Arthroplasty

OBJECTIVES

Prosthesis awareness is the perception of foreign bodies, which has a critical effect on the function of the prosthetic joint. In total hip arthroplasty (THA), the direct anterior approach (DAA) has more advantages than the posterior approach (PA), including superior rehabilitation outcomes. This study was to evaluate the recovery of "prosthesis awareness" through these two approaches.

METHODS

Three hundred and seventy-six patients who received THA with either DAA (n = 41) or PA (n = 335) from January 2016 to December 2017 were retrospectively analyzed. The Forgotten Joint Score-12 (FJS-12), Harris hip score (HHS), and visual analog scale (VAS) analyses were used to evaluate the recovery of "prosthesis awareness" in these patients 2 weeks, 1, 3, 6, and 12 months after surgery. The student t-test, Wilcoxon rank sum test, chi-square test, and MANOVA were used to compare the differences among groups.

RESULTS

We found that DAA patients had higher FJS-12 scores than PA patients at 2 weeks (42.15 ± 3.36 vs. 38.09 ± 3.28, p = 0.042), 1 month (49.06 ± 5.14 vs. 41.11 ± 5.21, p = 0.038), and 3 months (53.23 ± 4.07 vs. 48.09 ± 3.71, t = 3.152, p = 0.045). And the recovery rates of FJS-12 scores in DAA and PA groups at 2 weeks, 1 month, and 3 months after surgery were 75.46% ± 6.04%, 84.05% ± 6.57%, 91.37% ± 7.13%, and 74.14% ± 5.54%, 78.16% ± 6.01%, 88.23% ± 6.42%, respectively. To compare the recovery effects of the two procedures in more detail, we classified the 12 items in FJS-12 that evaluate different types of gravity center motions into three categories: low-movement group (LG), middle-movement group (MG), and high-movement group (HG). Interestingly, DAA patients had significantly higher HG than PA patients at 2 weeks, 1 month, and 3 months after operation (t = 3.225, p = 0.022 at 2 weeks, t = 3.081, p = 0.041 at 1 month and t = 2.783, p = 0.046 at 3 months), whereas no significant differences were observed in LG- and MG-related items. In addition, there were no significant differences in HHS and VAS scores between DAA and PA patients at 2 weeks (p = 0.102, p = 0.093), or from 1 month to 12 months (each p > 0.05).

CONCLUSIONS

DAA-mediated THA is superior to PA in terms of prosthesis adaptability and recovery of hip joint motion in the first 3 months after surgery, especially concerning high-movement gravity center motions.

Sarcopenia Is Associated with an Increased Risk of Postoperative Complications Following Total Hip Arthroplasty for Osteoarthritis

Sarcopenia is a state of catabolic muscle wasting prevalent in geriatric patients. Likewise, osteoarthritis is an age-related musculoskeletal disease affecting patients with similar demographics. Late-stage hip osteoarthritis is often treated with total hip arthroplasty (THA). As sarcopenia influences the surgical outcomes, this study aimed to assess the impact of sarcopenia on the outcomes of THA. A 1:3 matched case-control study of sarcopenic to control patients was performed using a large national database. In total, 3992 patients were analyzed. Sarcopenic patients undergoing THA were more likely to experience dislocation (odds ratio (OR) = 2.19, 95% confidence interval (CI) 1.21-3.91) within 1 year of THA. Furthermore, sarcopenic patients had higher urinary tract infection rates (OR = 1.79, CI 1.32-2.42) and a greater risk of 90-day hospital readmission (hazard ratio (HR) = 1.39, CI 1.10-1.77). Sarcopenic patients experienced more falls (OR = 1.62, CI 1.10-2.39) and fragility fractures (OR = 1.77, CI 1.34-2.31). Similarly, sarcopenic patients had higher day of surgery costs (USD 13,534 vs. USD 10,504) and 90-day costs (USD 17,139 vs. USD 13,394) compared with the controls. Ultimately, sarcopenic patients undergoing THA experience higher rates of postoperative complications and incur greater medical costs. Given the potential risks, orthopedic surgeons may consider treating or reducing the severity of sarcopenia before surgery.

Does fusion length matter? Total hip arthroplasty dislocation after extension of lumbosacral fusion: a case report

CASE

Hip-spine syndrome is a complex challenge for orthopedic surgeons. We present a 60-year-old female with a history of spinal fusion and total hip arthroplasty. The patient underwent extension of the previous fusion with sacropelvic fixation, and 5 months later she presented with left posterior prosthetic hip dislocation which required sedation and closed reduction.

CONCLUSION

Even with no change in lumbar lordosis or pelvic tilt and adequate acetabular cup position, extension of the fusion construct may predispose patients to dislocation. This may be the result of an increased lever arm acting at the hip joint, thereby leading to instability.

Association Between the Amount of Limb Lengthening and Hip Range of Motion After Total Hip Arthroplasty

AIMS

The relationship between prosthetic position and range of motion (ROM) after total hip arthroplasty (THA) has been rigorously examined. However, the effects of limb lengthening on postoperative hip ROM remain unclarified. We aimed to examine the effect of limb lengthening on hip ROM after THA.

METHODS

We retrospectively reviewed the data from 120 patients who underwent unilateral THA. Univariate and multivariate regression models were used to evaluate the effects of the following patient- and surgery-related covariates on hip flexion ROM at 3, 6, and 12 months after THA: age, sex, body mass index, diagnosis, preoperative University of California Los Angeles activity score, preoperative Oxford Hip Score, preoperative flexion ROM, amount of leg lengthening, cup inclination, and cup anteversion.

RESULTS

A large preoperative hip flexion ROM was the strongest predictor of a large hip flexion ROM at 12 months after THA (standardized coefficient: 0.519, P < 0.0001). A larger amount of leg lengthening was associated with a smaller postoperative hip flexion ROM (standardized coefficient: -0.159, P = 0.039), and male sex was another predictor of a smaller postoperative hip flexion ROM (standardized coefficient: -0.204, P = 0.014). Cup inclination (P = 0.99) and anteversion (P = 0.18) were not significantly associated with hip flexion ROM at 12 months after THA.

DISCUSSION

A large amount of limb lengthening was associated with decreased hip flexion ROM after THA. In THA, minimizing the leg length discrepancy is important; however, the postoperative improvement in hip flexion ROM may be limited when a large amount of leg lengthening is needed.

Discrepancy in the Responsiveness to Hip Range of Motion Between Harris and Oxford Hip Scores

Background

The primary objectives of total hip arthroplasty (THA) include mobility improvement and pain relief; however, the correlation between hip range of motion (ROM) and function remains unclear. We aimed to explore how ROM affects hip functions after THA and compare the responsiveness of each component of the modified Harris Hip Score (mHHS) and Oxford Hip Score (OHS) to preoperative and postoperative ROM.

Methods

This prospective observational study involved 120 patients who underwent unilateral THA. Univariate regression analyses were performed using the University of California Los Angeles activity score and mHHS and OHS to determine the effects of preoperative and postoperative flex ROM on clinical scores at 12 months. Multivariate regressions were performed to adjust for the confounding effects of patient factors: age, sex, body mass index, and diagnosis.

Results

A larger preoperative flexion ROM was associated with a higher score in the mHHS socks component (standardized coefficient [SC] = 0.26, P = .0041) at 12 months; the effect on the OHS socks component was not significant (P = .34). A larger flexion ROM at 12 months was associated with higher scores in the mHHS support (SC = 0.21, P = .026), stairs (SC = 0.35, P = .0002), and socks (SC = 0.32, P = .0007) components but had no significant effect on any OHS component. The effects of ROM on University of California Los Angeles activity score were limited.

Conclusions

A discrepancy was noted in the responsiveness to ROM between the two major measurement tools; this difference might be because mHHS and OHS are surgeon- and patient-administered questionnaires, respectively. This discrepancy also suggests that the patients have higher satisfaction than that assumed by the surgeons.

Anatomic stem inserted according to native anteversion could reproduce the native anterior distance of the femoral head and decrease bony impingement in total hip arthroplasty

PURPOSE

To investigate whether anatomic and straight stems could reproduce the anteroposterior distance (AD) of the native femoral head and evaluate the effect of AD of the femoral head on range of motion (ROM) and bony impingement.

METHODS

This retrospective simulation study included 64 patients who had undergone primary total hip arthroplasty between 2012 and 2014. Using computed tomography (CT)-based templating software, anatomic and straight stems were inserted with same alignment. AD of the head centre was compared between the two stems and native anatomy. Furthermore, post-operative ROM was calculated, and correlation between AD and ROM was assessed.

RESULTS

There was a strong positive correlation between native anteversion (mean 21.9°) and anatomic stem anteversion (mean 22.5°) (R = 0.975, P < 0.001). There was no significant difference in AD between the native and anatomic stems (mean 37.7 and 38.8 mm, respectively), but AD of the straight stem was significantly lower than that of the native and anatomic stems. The straight stem showed a significantly lower ROM in flexion and internal rotation angles with 90° flexion (IR) than the anatomic stem (P < 0.05 and P < 0.001, respectively). AD showed a stronger correlation with ROM of IR than with stem anteversion.

CONCLUSIONS

The anatomic stem could reproduce AD of the native femoral head centre, but the head centre of the straight stem in the same anteversion with anatomic stem translated significantly posterior, significantly decreasing the ROM of flexion and IR and increasing bony impingement of IR. To avoid bony impingement and acquire sufficient ROM, reproducing AD was important.

Clinical accuracy and precision of hip resurfacing arthroplasty using computed tomography-based navigation

PURPOSE

To avoid malalignment of components during hip resurfacing arthroplasty (HRA), we used a computed tomography (CT)-based navigation system for guidance. This study aimed to evaluate the clinical accuracy and precision of HRA performed using the CT-based navigation systems.

METHODS

HRA was performed on 17 hips guided by the CT-based navigation systems. We measured cup alignment deviation, deviation of the stem position, and alignment from the plan by image matching between pre-operative and post-operative CT images.

RESULTS

Cup anteversion was within 5° of that in the plan in all cases. Cup inclination was within 5° of that in the plan in 82.4% and within 10° in all cases. The angular difference of the stem was within 5° in all cases, and the entry point of the stem was within 4 mm in all cases.

CONCLUSION

The CT-based navigation system for HRA guided accurate component placement according to the plan.

Effect of soft-tissue impingement on range of motion during posterior approach Total Hip Arthroplasty: an in vivo measurement study

PURPOSE

While implant impingement and bony impingement have been recognized as causes of poor outcomes in total hip arthroplasty (THA), reports of soft-tissue impingement are rare. To clarify the issue, the effect of anterior capsule resection on hip range of motion (ROM) was quantitatively measured in vivo during posterior approach THA using a CT-based hip navigation system.

MATERIALS AND METHODS

For 47 patients (51 hips), hip ROM was measured intraoperatively before and after resection of the anterior hip capsule, and the difference was compared.

RESULTS

Resection of the anterior hip capsule brought about an average 6° increase of ROM in the direction of flexion with internal rotation and did not markedly change ROM in other directions.

CONCLUSIONS

During THA through a posterior approach, soft-tissue impingement by the anterior hip capsule can occur. Clinically, we expect that resection of the anterior hip capsule can reduce the risk of posterior instability without increasing the risk of anterior instability.