Function of reinserted abductor muscles after femoral replacement

Gluteus Maximus Transfer following Total Hip Arthroplasty Does Not Improve Abductor Moment: A Case-Control Gait Analysis Study of 15 Patients with Gluteus Medius Disruption

Gluteus maximus flap transfer (GMT) is a surgical technique used to improve gait kinematics and kinetics, as well as to reduce and ameliorate the functional outcome in patients with hip abductor deficiency following total hip arthroplasty (THA). The purpose of this observational study was to evaluate the gait pre- and postoperatively and examine whether GMT increases the abduction moment. Materials and Methods: A gait analysis based on reflective markers and force plates was performed in 15 patients who underwent GMT and were examined using an optical tracking system before and at a minimum of 13 months after the operation. The median follow-up time was 24 (13−60) months. The primary outcome was hip abduction moment (Nm/kg) during gait. The control group consisted of 15 female subjects without any gait pathology. Results: The mean adduction moment was significantly higher compared with controls before the operation (p = 0.02), but this did not apply to the abduction moment (p = 0.60). At the group level, the abduction moment did not improve postoperatively (p = 0.30). Only six of fifteen patients slightly improved their hip abduction moment postoperatively. However, speed (0.74 to 0.80 m/s) and cadence (94 to 105 steps/min) were improved (p < 0.03). Discussion: The results of this study showed no improvement in the hip abduction moment after GMT surgery. In our experience, abduction deficiency following primary THA is still a difficult and unsolved problem.

A long-term experience with Mutars tumor megaprostheses: analysis of 187 cases

PURPOSE

Modular megaprostheses have widely replaced allografts, as a reconstructive option; however, failures of these devices remain high. Aim of this study was to analyze outcomes, survival of the implants, incidence and types of complications with Mutars modular endoprostheses at long term.

METHODS

Between 2000 and 2019, 187 Mutars prostheses were implanted in two dedicated centers: 72 upper limbs and 115 lower limbs reconstructions. Diagnoses included 107 primary malignant bone or soft tissue tumors, 65 metastases, 8 benign bone tumors and 7 non-oncologic cases. Silver-coated prostheses were used in 118/187 (63%) cases.

RESULTS

At last follow-up, 76.5% of patients had retained their implant. The overall failure rate was 23.5% at a mean of 1.7 years. There were 22 mechanical failures and 22 non-mechanical failures. The overall implant survival to all types of failure was 68% and 52% at 5 and 10 years, respectively. Infection was the most common mode of failure with an incidence of 6.9%. Implant survival to infection was better for silver-coated implants than for standard implants even if with no significant difference (p = 0.56). Functional results were satisfactory in 97% of patients.

CONCLUSIONS

The overall implant survival at long term was satisfactory with Mutars prostheses. The incidence of complications with Mutars prosthesis is in line with the incidence reported in the literature with other types of tumor prosthesis. The most frequent cause of failure was infection with a lower incidence in silver-coated prostheses; silver coating seems to prevent infection in distal femur and proximal tibia. The silver coating seems to be particularly useful in two-stage revisions with a lower incidence of secondary amputation. In higher risk patients, silver-coated prostheses are the preferable choice for the reduction of the reinfection rate. The functional results of Mutars prostheses were excellent or good in most of cases. The current paper is design to enhance the literature on megaprosthesis in tumor surgery, proven that this system is one of the most used all over the word and one of the best performing.

Novel Cemented Technique for Trochanteric Fixation and Reconstruction of the Abductor Mechanism in Proximal and Total Femoral Arthroplasty: An Observational Study

Background

Little evidence exists regarding the clinical outcomes of cemented trochanteric fixation for abductor mechanism reconstruction in proximal or total femoral replacements. Clinical outcomes were assessed for a novel cemented technique for trochanteric fixation in femoral megaprostheses.

Methods

A descriptive series of 13 patients who underwent proximal or total femoral arthroplasty from 2016 to 2019 were reviewed. Radiographic trochanteric displacement >1 cm defined construct failure. A Kaplan-Meier survival analysis was performed to determine survival rates for these cemented constructs. Demographic information was obtained to better characterize the patient population in whom this technique was used.

Results

Eleven patients were included (age = 63.6 years; 45.4% females; body mass index = 31.7). Mean time to final radiographic follow-up was 73.8 weeks. Three of 11 (27.2%) patients had construct failure. Overall, survival at 1 year was 81.8%. At 2 years, survival of cemented constructs was 65.5%. More construct failures occurred in patients who sustained a postoperative dislocation than in those who did not (P = .05).

Conclusions

This novel cemented trochanteric fixation technique for reconstruction of the abductor mechanism in femoral megaprostheses had 81.8% survival at 1 year postoperatively. While longitudinal comparative studies with larger samples are needed, the cemented technique may provide a viable alternative to traditional cementless methods of trochanteric fixation. Increased construct failure rates after postoperative dislocation highlight the importance of robust abductor reconstruction in these implants.

Techniques and outcomes of hip abductor reconstruction following tumor resection in adults

The function of the abductor mechanism (AM) of the hip can be disturbed, or even compromised, following tumor resection in the hip area. The consequences are instability (limping, dislocation), pain and altered walking ability. Several reconstruction techniques can be used for the same AM sacrifice. After defining the AM, this lecture will discuss the best technique for a given type of bone and muscle resection. These reconstruction techniques depend on exactly where the AM was sacrificed. For zone 1 resections of the ilium and/or iliac gluteal insertions, reconstruction is often optional. When muscle from the AM is resected, especially when the gluteal tendon is detached from its trochanteric insertion, isolated reconstruction can be done or reconstruction in combination with a tendon allograft or an allograft and/or tendon transfer from the surrounding area. This sacrifice, whether followed by reconstruction or not, in most cases leads to a good functional outcome, except when a complete musculotendinous unit or the superior gluteal nerve is sacrificed. Isolated resection of the greater trochanter is rare; however, this completely disrupts the continuity of the AM and justifies reconstruction, often using a bone-tendon allograft. Proximal femur resection is the most common scenario. The extent of the trochanteric resection and the gluteal tendon attachments drives the type of prosthesis used. The two most used techniques consist in an allograft sleeve over a long cemented femoral stem (allograft prosthesis composite - APC) or a modular proximal femoral endoprosthesis (megaprosthesis) with a specific AM fixation system (small plate or wire cerclage, resorbable or metal wire, synthetic reattachment tube). These two techniques yield nearly identical long-term functional outcomes with complications specific to each: osteolysis and fracture for APC, failure of tendon reattachment for megaprosthesis. Beyond these technical considerations, one must consider the poor availability of massive bone allografts. This is a highly relevant issue in France, and partially explains the shift to reconstruction with a megaprosthesis. Lastly, we will look at the different clinical and diagnostic tests used to evaluate the function of the AM in an oncology context and the outcomes of the various types of reconstruction.

Clinical and dynamometric results of hip abductor system repair by trochanteric hydroxyapatite plate with modular implant after resection of proximal femoral tumors

INTRODUCTION

The capacity of the hydroxyapatite-coated trochanteric screwed plates used with modular hip implants to restore abductor system efficacy after proximal femoral tumor resection has never been assessed. We therefore conducted a retrospective study aiming to: (1) quantitatively evaluate abduction conservation on dynamometry according to use of digastric reinsertion, conserving continuity between the gluteus medius and vastus lateralis muscles, or not, and of standard versus small-offset; (2) assess radiographic trochanteric plate fixation; (3) assess functional scores; and (4) assess complications.

HYPOTHESIS

Trochanteric reinsertion better conserves abduction strength when reinsertion is digastric.

PATIENTS AND METHODS

Thirty-one patients undergoing proximal femoral tumor resection between 2006 and 2016 with reconstruction by Stanmore METS™ modular implant with trochanteric plate were included. Twenty-one had digastric fixation between the gluteus medius and vastus lateralis and 10 had simple trochanteric fixation without digastric continuity. Abduction strength was compared between sides on dynamometer. Sixteen patients had full assessment of muscle strength, by a single observer; there were 8 deaths, 5 patients lost to follow-up, and 2 cases of material removal.

RESULTS

Abduction strength conservation versus the contralateral side was 55.2±23.3% (range, 5.8-86.1%): 66.6±13.0% (46.4-86.1) with versus 36.0±24.7% (5.8-63.2%) without digastric continuity (p=0.01); severe limp rate was 4/21 when digastric continuity was preserved (19%) versus 6/10 (60%) (p=0.04), and radiologic trochanteric reinsertion stability rate was 19/21 (90%) versus 4/10 (40%) (p=0.005). Standard femoral offset conserved greater abduction strength: 64.9±20.0% versus small-offset 45.4±23.2% (p=0.05). Toronto Extremity Salvage Score (TESS) was 89±9.4%, and Musculoskeletal Tumor Society (MSTS) score 75.4±5.4%. There were 6 complications (19%): 4 infections, 1 dislocation, and 1 plate removal; the single dislocation (3%) was in the digastric conservation group. TESS (90.7±7.8% vs 88.3±4) and MSTS score (75.6±4.0% vs 75.1±3.7) and complications [4/21 (19%) vs 2/10 (20%)] did not differ according to digastric or non-digastric reinsertion (p=1).

CONCLUSIONS

Abduction strength with a modular implant using a hydroxyapatite-coated trochanteric plate was better conserved by digastric trochanteric reinsertion, resulting in less limping, although the complications rate and functional scores were unaffected. Longer term assessment is needed to confirm this conservation of abduction strength.

LEVEL OF EVIDENCE

IV, retrospective study without control group.

Is endoprosthetic replacement of the proximal femur appropriate in the comorbid patient?

INTRODUCTION

Patients with failed hip arthroplasty requiring extensive femoral reconstruction often present with a multitude of comorbidities. Many treatment options limit initial mobilisation relying on bone graft incorporation. The use of endoprosthetic replacement (EPR), despite often being a "last resort", offers an expeditious solution with early mobilisation that is crucial in the comorbid individual. Many perceive that the surgical insult of EPR is associated with an increased mortality. The aim of this study was to report our experience of proximal femoral EPR as the treatment for failed arthroplasty or fracture fixation. Primary outcomes included mortality, complications, revision and function.

METHODS

Retrospective review of proximal femoral EPR undertaken at our institution for non-oncological indications between 2007 and 2015 identified 37 patients with a mean follow-up of 33 months. Patient case notes, demographics and radiographs were studied.

RESULTS

The 90-day mortality following proximal femoral EPR was 2.7%. 9 patients had died at the time of final follow-up (mean time to death was 33 months). The mean preoperative and postoperative Oxford Hip Score improved from 8 to 31 respectively (p<0.05). When considering revision for any cause, 5-year survival was 94.6%. 2 patients suffered periprosthetic joint infection and 1 patient required revision for prosthesis dislocation.

CONCLUSIONS

We report a relatively low incidence of perioperative complications, with a mortality rate similar to other revision options in this high-risk cohort. Whilst further revision may not always be possible, this "last resort" technique is safe in the comorbid population presenting with significant proximal femoral bone deficiency.

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.

Failure mode classification for tumor endoprostheses: retrospective review of five institutions and a literature review

BACKGROUND

Massive endoprostheses provide orthopaedic oncologists with many reconstructive options after tumor resection, although failure rates are high. Because the number of these procedures is limited, failure of these devices has not been studied or classified adequately. This investigation is a multicenter review of the use of segmental endoprostheses with a focus on the modes, frequency, and timing of failure.

METHODS

Retrospective reviews of the operative databases of five institutions identified 2174 skeletally mature patients who received a large endoprosthesis for tumor resection. Patients who had failure of the endoprosthesis were identified, and the etiology and timing of failure were noted. Similar failures were tabulated and classified on the basis of the risk of amputation and urgency of treatment. Statistical analysis was performed to identify dependent relationships among mode of failure, anatomic location, and failure timing. A literature review was performed, and similar analyses were done for these data.

RESULTS

Five hundred and thirty-four failures were identified. Five modes of failure were identified and classified: soft-tissue failures (Type 1), aseptic loosening (Type 2), structural failures (Type 3), infection (Type 4), and tumor progression (Type 5). The most common mode of failure in this series was infection; in the literature, it was aseptic loosening. Statistical dependence was found between anatomic location and mode of failure and between mode of failure and time to failure. Significant differences were found in the incidence of failure mode Types 1, 2, 3, and 4 when polyaxial and uniaxial joints were compared. Significant dependence was also found between failure mode and anatomic location in the literature data.

CONCLUSIONS

There are five primary modes of endoprosthetic failure, and their relative incidences are significantly different and dependent on anatomic location. Mode of failure and time to failure also show a significant dependence. Because of these relationships, cumulative reporting of segmental failures should be avoided because anatomy-specific trends will be missed. Endoprosthetic design improvements should address failure modes specific to the anatomic location.

Endoprosthetic and allograft-prosthetic composite reconstruction of the proximal femur for bone neoplasms

Reconstruction of the proximal femur after tumor resection can be achieved with either an endoprosthesis or an allograft-prosthetic composite. We compared the two modalities for complications, functional outcome, and construct survival. We retrospectively analyzed 52 patients with endoprostheses and 20 with allograft-prosthetic composite reconstructions between 1974 and 2002. Median followup was 146 months and 76 months, respectively. Both methods were associated with low rates of early complications. Infections occurred in two patients with endoprostheses and one patient with an allograft-prosthetic composite reconstruction. Aseptic loosening was the most common (10%) late complication for patients with endoprostheses. Nonunion was the most common (10%) complication for patients with allograft prosthetic composite reconstructions. All host-allograft junctions eventually healed after bone-grafting. The Musculo skeletal Tumor Society scores were similar for patients with endoprostheses (70%) and allograft-prosthetic composites (82%). The median hip abductor strength was greater for patients with allograft-prosthetic composite reconstructions (4.6 of 5) than for patients with endoprostheses (2.8 of 5). Kaplan-Meier survivorship of the implant was 86% for both groups at 10 years. The consistent restoration of abductor muscle strength combined with the low morbidity and high durability support the use of allograft-prosthetic composite reconstruction in patients with long life expectancy.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Proximal femoral replacements with megaprostheses

The exact role of proximal femoral replacement (megaprosthesis) in revision hip surgery is unclear. During the past decade remarkable advances in the field of revision hip reconstruction have been made including the availability of allograft cancellous and cortical bone. With the increased use of cortical strut grafts to augment host bone, the indications for the use of megaprostheses have narrowed. Currently, we reserve the use of megaprostheses for elderly or sedentary patients with massive proximal femoral bone loss that cannot be reconstructed by other reconstructive procedures. This may include failed total hip arthroplasty (THA), nonunion of the proximal femur with multiple failed attempts at osteosynthesis, and hip salvage after a failed resection arthroplasty.

Reconstruction of the pelvis after tumor resection in children and adolescents

Thirty patients younger than 19 years with malignant bone tumors of the pelvis were treated by limb salvage surgery between 1970 and 1998. Functional and oncologic results were reviewed retrospectively. In 10 patients the defect was reconstructed by an endoprosthesis and in 20 patients reconstruction by autologous grafts (n = 7), allograft and prosthesis combinations (n = 2), bone cement reconstruction (n = 1), iliosacral arthrodesis (n = 1), modified Girdlestone procedure (n = 3), or resection without reconstruction (n = 6) was done. Three and one-half reoperations per patient were necessary postoperatively after allograft reconstruction, 2.5 reoperations per patient were necessary after endoprosthetic reconstruction, and 0.8 reoperations per patient were necessary after other or no reconstruction. After a mean followup of 52 months (range, 2-241 months), 17 patients were alive, 15 of whom were continuously disease-free, and 13 patients had died of their disease. Functional ratings were 81% after autograft, 73% after allograft, and 60% after endoprosthetic reconstruction. Defect reconstruction varied according to the type of resection. Type I resections were best reconstructed by biologic methods. Endoprosthetic reconstruction after periacetabular resection with the advantage of preservation of a functional hip and body integrity was associated with a high rate of complications and reoperations. Its role compared with allograft reconstruction, modified Girdlestone procedure, or no reconstruction requires additional investigation.

Proximal femur reconstruction by an allograft prosthesis composite

Twenty-seven patients who had resection of the proximal femur for bone tumors and reconstruction with an allograft prosthesis composite are reported. In most of the patients, the prosthesis was a long-stem revision type, cemented in the allograft and uncemented in the femoral shaft. The abductor muscles and iliopsoas were sutured to the corresponding tendons on the allograft. Implant-related complications and functional results were evaluated and are reported. Twenty-two patients achieved a minimum followup of 36 months (range, 36-126 months; average, 58 months). The implant was removed in two patients (one for infection, one for intraoperative fracture of the allograft). One patient experienced nonunion, whereas in the remaining 24 patients, the allograft eventually united to the host bone. A frequent late complication (17 patients) was fracture of the greater trochanter of the allograft. In the whole series, only four new operations were done for implant-related complications. In 22 patients who could be evaluated, the functional evaluation according to the Musculoskeletal Tumor Society System was excellent in 16 (73%) patients, good in four (18%), and fair in two (9%). These results compare favorably with those of megaprostheses for tumor resection of the proximal femur, where a Trendelenburg gait almost always is present.