Acetabular cup revision combined with tensor facia lata reconstruction for management of massive abductor avulsion after failed total hip arthroplasty

Impact of fatty degeneration on the functional outcomes of 38 patients undergoing surgical repair of gluteal tendon tears

BACKGROUND

Gluteal tendon tears (GTT) can cause pain and weakness of the hip. We analyze the impact of gluteal muscle fatty degeneration, atrophy and tear morphology on clinical outcomes of surgical repair.

METHODS

All sequential patients receiving surgical repair of GTTs via anchor sutures between 1/2015 and 11/2018 were retrospectively identified. MRIs were reviewed by a radiologist for tendon retraction, muscle atrophy and tear size. The Goutallier-Fuchs Classification (GFC) was used to quantify fatty degeneration as < 2° or ≥ 2°. Demographic and clinical variables were abstracted from the electronic records. The surveys HHS Section 1 and HOOS Jr. were obtained at last follow-up. The Pearson correlation and one-way ANOVA tests served for statistical analysis of clinical variance.

RESULTS

38 patients were identified, 29 (76.3%) were female. The average age was 67. Of the 11 (28.9%) patients with a prior hip arthroplasty 87.5% of primary THAs had a direct lateral approach. 29 (76.3%) patients were treated open and 9 (23.7%) arthroscopically. At an average follow-up of 20.9 months, patients reported a significant improvement in pain (97%), analgesic use (85.7%), limp (52.6%) and abduction strength (54.2%) (all: P ≤ 0.01). GFC ≥ 2° were associated with significantly worse outcomes in terms of limp (0.19/3 vs. 1.2/3, P = 0.05), HHS-S1 (58.19 vs. 71.68, P = 0.04) and complication rates (37.5% vs. 0%, P = 0.02). There was a strong correlation between tear retraction (P = 0.005), tear size (P = 0.009) and muscle atrophy (P = 0.001) with GFC ≥ 2° but not with clinical outcomes. GFC ≥ 2° was strongly related to lateral THA exposures (P < 0.001). Surgical approach had no impact on clinical outcomes.

CONCLUSION

While fatty degeneration can negatively impact functional outcomes, pain relief is reliably achieved. Tear morphology and muscle atrophy did not correlate with outcomes in this patient cohort. Patients should be counseled to expect a residual limp after surgery if they have GFC ≥ 2° on MRI.

A roadmap to develop clinical guidelines for open surgery of acute and chronic tears of hip abductor tendons

PURPOSE

Abductor tendon tears are increasingly recognised as a common cause of lateral hip pain. Surgical treatment of these tears has been recommended, but the indications and types of open surgery have not been precisely elucidated yet. This manuscript aimed to critically review the literature concerning all open treatment options for this condition while identifying knowledge gaps and introducing a treatment algorithm.

METHODS

Literature search was conducted, including PubMed, Cochrane library, ScienceDirect and Ovid MEDLINE from 2000 to May 2020. Inclusion criteria were set as: (i) clinical studies reporting outcomes following open surgical treatment of acute or chronic hip abductor tendon tears, (ii) studies reporting an open direct or augmented suturing or muscle transfer procedure, (iii) acute or chronic tears found in native or prosthetic hips.

RESULTS

A total of 34 studies published between 2004 and 2020 were included. The vast majority of studies were uncontrolled case series of a single treatment method. A total of 970 patients (76% women) with an age range between 48 and 76 years were involved. Women between 60 and 75 years old were most commonly treated. Preoperative evaluation of patients and reporting of open surgical technique and outcomes are inconsistent. All studies reported variable improvement of pain, functional outcomes and gait of patients. Overall, complication rates ranged from 0 to 31.2%.

CONCLUSION

The current literature on this topic is highly heterogeneous, and the overall level of the available evidence is low. A roadmap to develop practical guidelines for open surgery of acute and chronic tears of abductor tendons is provided. The anatomy and chronicity of the lesion, the extent of fatty infiltration and neurologic integrity of hip abductor muscles may influence both treatment choice and outcome. Further high-quality studies with standardisation of preoperative evaluation of patients and reporting of outcomes will help delineate best treatments.

LEVEL OF EVIDENCE

IV.

High Incidence of Irradiated Cortical Strut Allograft Resorption Following Revision of Femoral Stems

BACKGROUND

Despite the widespread use of revision total hip arthroplasties using cementless stems and cortical strut allografts, graft resorption has not been explicitly studied.

METHODS

Between 2010 and 2018, 40 femoral strut grafts were used in the revision of femoral stems of 36 patients (18 males and 18 females; average age, 51.9 ± 12.9 years). The mean follow-up was 78.9 ± 37.3 months. Failure was defined as revision surgery for any reason and subsidence of greater than 5 mm.

RESULTS

The survival rate of the stem without the need for revision at 5 years was 95% (mean graft survival time, 10.8 [95% CI, 9.414-12.234] years). Overall survival with graft resorption as the endpoint was 90% at 5 years (mean graft survival time, 8.8 [95% CI, 7.5-10.2] years). Survival with graft nonunion as the endpoint was 90% at 3 years (mean survival time, 11.7 [95% CI, 10.5-12.8] years).

CONCLUSION

The resorption rate increases proportionally to the follow-up duration and can be very severe in a high percentage of cases. Long-term multicenter studies are required to assess the effect of resorption on prosthesis longevity.

[Surgical repair of gluteus medius muscle in hip replacement surgery]

Injury of gluteus medius muscle is a serious often complication after hip replacement surgery followed by pain, claudication and significant deterioration of the quality of life. Prevention of intraoperative injury of this muscle is especially relevant in young patients. Normal function of this muscle provides rapid rehabilitation and early postoperative recovery. However, hip replacement surgery through Hardinge's direct lateral approach is accompanied by fatty degeneration of gluteus medius muscle in 12-20% of cases. Moreover, two or more redo procedures lead to fatty degeneration of almost 70% of anterior and 40% of central muscular segment. Currently, there are many methods of surgical treatment of this complication including transosseous muscle fixation, endoscopic procedures, repair using Achilles tendon, gluteus maximus muscle, lateral head of quadriceps muscle and allografts. However, various publications devoted to this problem have certain disadvantages including short follow-up period, small sample size and often unsatisfactory outcomes. Therefore, the question of surgical repair of hip abductor function remains open.

Cell therapy to improve regeneration of skeletal muscle injuries

Diseases that jeopardize the musculoskeletal system and cause chronic impairment are prevalent throughout the Western world. In Germany alone, ~1.8 million patients suffer from these diseases annually, and medical expenses have been reported to reach 34.2bn Euros. Although musculoskeletal disorders are seldom fatal, they compromise quality of life and diminish functional capacity. For example, musculoskeletal disorders incur an annual loss of over 0.8 million workforce years to the German economy. Among these diseases, traumatic skeletal muscle injuries are especially problematic because they can occur owing to a variety of causes and are very challenging to treat. In contrast to chronic muscle diseases such as dystrophy, sarcopenia, or cachexia, traumatic muscle injuries inflict damage to localized muscle groups. Although minor muscle trauma heals without severe consequences, no reliable clinical strategy exists to prevent excessive fibrosis or fatty degeneration, both of which occur after severe traumatic injury and contribute to muscle degeneration and dysfunction. Of the many proposed strategies, cell-based approaches have shown the most promising results in numerous pre-clinical studies and have demonstrated success in the handful of clinical trials performed so far. A number of myogenic and non-myogenic cell types benefit muscle healing, either by directly participating in new tissue formation or by stimulating the endogenous processes of muscle repair. These cell types operate via distinct modes of action, and they demonstrate varying levels of feasibility for muscle regeneration depending, to an extent, on the muscle injury model used. While in some models the injury naturally resolves over time, other models have been developed to recapitulate the peculiarities of real-life injuries and therefore mimic the structural and functional impairment observed in humans. Existing limitations of cell therapy approaches include issues related to autologous harvesting, expansion and sorting protocols, optimal dosage, and viability after transplantation. Several clinical trials have been performed to treat skeletal muscle injuries using myogenic progenitor cells or multipotent stromal cells, with promising outcomes. Recent improvements in our understanding of cell behaviour and the mechanistic basis for their modes of action have led to a new paradigm in cell therapies where physical, chemical, and signalling cues presented through biomaterials can instruct cells and enhance their regenerative capacity. Altogether, these studies and experiences provide a positive outlook on future opportunities towards innovative cell-based solutions for treating traumatic muscle injuries-a so far unmet clinical need.

Immunomodulatory placental-expanded, mesenchymal stromal cells improve muscle function following hip arthroplasty

BACKGROUND

No regenerative approach has thus far been shown to be effective in skeletal muscle injuries, despite their high frequency and associated functional deficits. We sought to address surgical trauma-related muscle injuries using local intraoperative application of allogeneic placenta-derived, mesenchymal-like adherent cells (PLX-PAD), using hip arthroplasty as a standardized injury model, because of the high regenerative and immunomodulatory potency of this cell type.

METHODS

Our pilot phase I/IIa study was prospective, randomized, double blind, and placebo-controlled. Twenty patients undergoing hip arthroplasty via a direct lateral approach received an injection of 3.0 × 10⁸ (300 M, n = 6) or 1.5 × 10⁸ (150 M, n = 7) PLX-PAD or a placebo (n = 7) into the injured gluteus medius muscles.

RESULTS

We did not observe any relevant PLX-PAD-related adverse events at the 2-year follow-up. Improved gluteus medius strength was noted as early as Week 6 in the treatment-groups. Surprisingly, until Week 26, the low-dose group outperformed the high-dose group and reached significantly improved strength compared with placebo [150 M vs. placebo: P = 0.007 (baseline adjusted; 95% confidence interval 7.6, 43.9); preoperative baseline values mean ± SE: placebo: 24.4 ± 6.7 Nm, 150 M: 27.3 ± 5.6 Nm], mirrored by an increase in muscle volume [150 M vs. placebo: P = 0.004 (baseline adjusted; 95% confidence interval 6.0, 30.0); preoperative baseline values GM volume: placebo: 211.9 ± 15.3 cm³ , 150 M: 237.4 ± 27.2 cm³ ]. Histology indicated accelerated healing after cell therapy. Biomarker studies revealed that low-dose treatment reduced the surgery-related immunological stress reaction more than high-dose treatment (exemplarily: CD16+ NK cells: Day 1 P = 0.06 vs. placebo, P = 0.07 vs. 150 M; CD4+ T-cells: Day 1 P = 0.04 vs. placebo, P = 0.08 vs. 150 M). Signs of late-onset immune reactivity after high-dose treatment corresponded to reduced functional improvement.

CONCLUSIONS

Allogeneic PLX-PAD therapy improved strength and volume of injured skeletal muscle with a reasonable safety profile. Outcomes could be positively correlated with the modulation of early postoperative stress-related immunological reactions.

Reconstruction of chronic abductor deficiency after revision hip arthroplasty using an extensor mechanism allograft

This study reports the clinical outcome of reconstruction of deficient abductor muscles following revision total hip arthroplasty (THA), using a fresh-frozen allograft of the extensor mechanism of the knee. A retrospective analysis was conducted of 11 consecutive patients with a severe limp because of abductor deficiency which was confirmed on MRI scans. The mean age of the patients (three men and eight women) was 66.7 years (52 to 84), with a mean follow-up of 33 months (24 to 41). Following surgery, two patients had no limp, seven had a mild limp, and two had a persistent severe limp (p = 0.004). The mean power of the abductors improved on the Medical Research Council scale from 2.15 to 3.8 (p < 0.001). Pre-operatively, all patients required a stick or walking frame; post-operatively, four patients were able to walk without an aid. Overall, nine patients had severe or moderate pain pre-operatively; ten patients had no or mild pain post-operatively. At final review, the Harris hip score was good in five patients, fair in two and poor in four. We conclude that using an extensor mechanism allograft is relatively effective in the treatment of chronic abductor deficiency of the hip after THA when techniques such as local tissue transfer are not possible. Longer-term follow-up is necessary before the technique can be broadly applied.

Muscle atrophy and metal-on-metal hip implants: a serial MRI study of 74 hips

BACKGROUND AND PURPOSE

Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time.

PATIENTS AND METHODS

We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23-83) years. The median time post-implantation was 83 (35-142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined.

RESULTS

The median blood cobalt was 6.84 (0.24-90) ppb and median chromium level was 4.42 (0.20-45) ppb. The median Oxford hip score was 34 (5-48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02).

INTERPRETATION

Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs.

Significant muscle damage after multiple revision total hip replacements through the direct lateral approach

Intact abductors of the hip play a crucial role in preventing limping and are known to be damaged through the direct lateral approach. The extent of trauma to the abductors after revision total hip replacement (THR) is unknown. The aim of this prospective study was to compare the pre- and post-operative status of the gluteus medius muscle after revision THR. We prospectively compared changes in the muscle and limping in 30 patients who were awaiting aseptic revision THR and 15 patients undergoing primary THR. The direct lateral approach as described by Hardinge was used for all patients. MRI scans of the gluteus medius and functional analyses were recorded pre-operatively and six months post-operatively. The overall mean fatty degeneration of the gluteus medius increased from 35.8% (1.1 to 98.8) pre-operatively to 41% (1.5 to 99.8) after multiple revision THRs (p = 0.03). There was a similar pattern after primary THR, but with considerably less muscle damage (p = 0.001), indicating progressive muscle damage. Despite an increased incidence of a positive Trendelenburg sign following revision surgery (p = 0.03) there was no relationship between the cumulative fatty degeneration in the gluteus medius and a positive Trendelenburg sign (p = 0.26). The changes associated with other surgical approaches to the hip warrant investigation.