Total knee replacement versus osteochondral allograft in proximal tibia bone tumours

Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions of the knee remain a difficult entity to treat. Current treatment options include arthroscopic debridement, microfracture, autograft or allograft osteochondral transplantation, and cell-based therapies such as autologous chondrocyte transplantation. Osteochondral transplantation techniques restore the normal topography of the condyles and provide mature hyaline cartilage in a single-stage procedure. However, clinical outcomes comparing autograft versus allograft techniques are scarce.

PURPOSE

To perform a comprehensive systematic review and meta-analysis of high-quality studies to evaluate the results of osteochondral autograft and allograft transplantation for the treatment of symptomatic cartilage defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 2.

METHODS

A comprehensive search of the literature was conducted using various databases. Inclusion criteria were level 1 or 2 original studies, studies with patients reporting knee cartilage injuries and chondral defects, mean follow-up ≥2 years, and studies focusing on osteochondral transplant techniques. Exclusion criteria were studies with nonknee chondral defects, studies reporting clinical outcomes of osteochondral autograft or allograft combined with other procedures, animal studies, cadaveric studies, non-English language studies, case reports, and reviews or editorials. Primary outcomes included patient-reported outcomes and failure rates associated with both techniques, and factors such as lesion size, age, sex, and the number of plugs transplanted were assessed. Metaregression using a mixed-effects model was utilized for meta-analyses.

RESULTS

The search resulted in 20 included studies with 364 cases of osteochondral autograft and 272 cases of osteochondral allograft. Mean postoperative survival was 88.2% in the osteochondral autograft cohort as compared with 87.2% in the osteochondral allograft cohort at 5.4 and 5.2 years, respectively (P = .6605). Patient-reported outcomes improved by an average of 65.1% and 81.1% after osteochondral autograft and allograft, respectively (P = .0001). However, meta-analysis revealed no significant difference in patient-reported outcome percentage change between osteochondral autograft and allograft (P = .97) and a coefficient of 0.033 (95% CI, -1.91 to 1.98). Meta-analysis of the relative risk of graft failure after osteochondral autograft versus allograft showed no significant differences (P = .66) and a coefficient of 0.114 (95% CI, -0.46 to 0.69). Furthermore, the regression did not find other predictors (mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location) that may have significantly affected patient-reported outcome percentage change or postoperative failure between osteochondral autograft versus allograft.

CONCLUSION

Osteochondral autograft and allograft result in favorable patient-reported outcomes and graft survival rates at medium-term follow-up. While predictors for outcomes such as mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location did not affect the comparison of the 2 cohorts, proper patient selection for either procedure remains paramount to the success and potentially long-term viability of the graft.

Prosthetic reconstruction following resection of lower extremity bone neoplasms: A systematic review and meta-analysis

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Prosthetics are the mainstay in surgery after resection of extremity bone tumors.

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For these patients gait parameters deteriorated compared to healthy individuals.

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Further refinement of surgical techniques is required.

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New rehabilitation strategies and follow-up programming are needed.

Prosthetic reconstructive procedures have become the mainstay in contemporary surgical treatment following resection of extremity bone neoplasms. Given that these patients are of young age most of the time, achievement of robust functional outcomes is of paramount importance. The aim of this study is to assess the impact of this procedure on the gait parameters of cancer patients compared to healthy individuals. The Medline, Scopus and Cochrane databases were systematically searched until January 2022 for eligible studies. Gait parameters measured by gait analysis after prosthetic reconstruction were the outcomes of interest. Eight cohort studies were included in our analysis. From these, seven studied prosthetic reconstruction of the knee (distal femur or proximal tibia) and only one exclusively studied prostetic reconstructions of the proximal femur. Compared to healthy individuals a significant decrease was evident in gait velocity (-0.16 m/sec, 95 %CI: −0.23 to −0.09, p-value < 0.001), in stride length (-6.07 %height, 95 %CI: −9,36 to −2.78, p-value < 0.001), in cadence (-3.96 stride/min, 95 %CI: −5.41 to −2.51, p-value < 0.001) and significant increase in cycle time (0.10 s, 95 %CI: 0.03 to 0.17, p-value = 0.005). Prosthetic reconstruction following lower limb tumor resection significantly affects the gait of patients. This knowledge can be utilized for further refinement of surgical techniques, rehabilitation strategies and follow-up programming.

Patella cryo-free technique with recycled frozen autograft reconstruction preserves extensor mechanism for proximal tibial malignancy

BACKGROUNDS

We designed a patella cryo-free method to protect patella from cryoinjury during recycled frozen bone-prosthesis-composite reconstruction for proximal tibial malignancy. This study aimed to use animal model to ensure safety and efficacy of this method and reported our clinical outcomes.

METHODS

Six swine proximal tibias along with patella and patellar tendon were harvested and dived into group A (n = 3, traditional patella freezing) and group B (n = 3, patella cryo-free). Temperature curve measurement, histological analysis, and TUNEL assay were performed in both groups. Clinically, we retrospectively reviewed 23 patients with proximal tibia malignant bone tumor (13: traditional patella freezing method; 10: patella cryo-free method). The clinical and functional outcomes were reported and compared in both groups.

RESULTS

Temperature curve of the group B showed that ideal therapeutic temperature (<-60°C) required to kill tumor cells can be achieved in the proximal tibia while the innocent patella can be kept in room temperature at all time. Histological analysis showed better preservation of the cartilage tissue in patella of group B. TUNEL assay showed significantly more apoptotic cells in the frozen tibia of both groups and frozen patella of group A. When reviewing our clinical results, less complication of the patella as well as better functional preservation were found in patients subjecting to patella cryo-free method. No local recurrence was observed in either group.

CONCLUSION

Patellar cryo-free technique could protect patella from cryoinjury during freezing and therefore preserve more extensor functions for patients with proximal tibial malignant bone tumors.

The results of patellar stainless steel wire extensor mechanism reconstruction in proximal tibial tumour excision mega-prosthesis surgeries for proximal tibial sarcomas

BACKGROUND

Extensor mechanism function after a proximal tibial tumour excision is the major determining factor for the limb function. However, problems of extensor lag, delayed healing and poor functional outcomes exist with the previous methods of its reconstruction. We describe a novel technique of using a patellar stainless steel (SS) wire to reconstruct the extensor apparatus of the knee in non-porous coated implants and examine the functional outcome and associated complications.

METHODS

This was a retrospective analytical interventional study. Twenty-six patients operated between 2011 and 2019 were included. Extensor lag measured at 6 months and 12 months postoperative, total range of motion at 12 months and Musculoskeletal Tumor Society (MSTS) score at the final visit were retrieved. Complications that occurred during the follow up period were noted. Patellar position was measured using comparative patellar-position-ratio.

RESULTS

Mean extensor lag at 6 months was 18.5° which improved to 8.7° at 12 months. Patellar malposition and deep infection were found to be the causes of poor functional outcome. A patellar-position-ratio between 0.9 and 1.1 led to a well-functioning extensor apparatus. Four patients underwent above-knee amputations. Deep infection and amputations reduced the MSTS score. An SS wire give way after 6 months did not affect the extensor power. A medial gastrocnemius flap reduced the infection rates.

CONCLUSION

Patellar SS wiring is an effective technique for reconstructing the knee extensor apparatus following a proximal tibial tumour excision mega-prosthesis. Proper position of the SS wire prevents wire-related complications. For a well-functioning extensor apparatus, use of a gastrocnemius flap cover intra-operatively is pertinent along with lack of infection for a pain-free, stable and mobile limb.

Surface Electromyography Applied to Gait Analysis: How to Improve Its Impact in Clinics?

Surface electromyography (sEMG) is the main non-invasive tool used to record the electrical activity of muscles during dynamic tasks. In clinical gait analysis, a number of techniques have been developed to obtain and interpret the muscle activation patterns of patients showing altered locomotion. However, the body of knowledge described in these studies is very seldom translated into routine clinical practice. The aim of this work is to analyze critically the key factors limiting the extensive use of these powerful techniques among clinicians. A thorough understanding of these limiting factors will provide an important opportunity to overcome limitations through specific actions, and advance toward an evidence-based approach to rehabilitation based on objective findings and measurements.

Reconstruction of knee extensor with patellar tendon autograft following intraoperative radiotherapy

BACKGROUND

Patellar tendon autograft after intraoperative extracorporeal radiotherapy has been used for reconstruction of the extensor mechanism following limb-sparing wide tumor resection around the knee. The purpose of this study was to determine the clinical outcome of this reconstruction technique.

METHODS

We retrospectively reviewed six consecutive patients with peripatellar tendon and proximal tibial sarcoma who underwent reconstruction of the knee extensor mechanism. The resection area was planned to be contained with the patellar tendon in order to obtain a wide margin. First, the patella was osteotomized at the midline, and the inferior half of patella, patellar tendon, and tibial tuberosity were excised en bloc. The resected segments were devitalized with intraoperative extracorporeal radiotherapy and reimplanted into the original site. A follow-up evaluation included an assessment of the range of motion, extensor lag, the International Society of Limb Salvage score, and complications.

RESULTS

Six patients were followed up for 121-270 months. One patient underwent an additional reconstruction with total knee arthroplasty due to a collapse of the tibial subchondral bone. A supracondylar fracture of the femur occurred in two patients, and a delayed union of the osteosynthesis site of the tibial shaft was observed in one patient. At the latest follow up, extensor lag had a median of five degrees, and International Society of Limb Salvage scores had a median of 83%. No local recurrence or rupture of the patellar tendon was observed.

CONCLUSIONS

Reconstruction of the knee extensor mechanism using a patellar tendon treated with intraoperative radiotherapy is a reliable and successful method.

Fitness, Function, and Exercise Training Responses after Limb Salvage With a Lower Limb Megaprosthesis: A Systematic Review

OBJECTIVE

To describe the fitness, function, and exercise training responses of patients following reconstruction of the lower limb with a total femoral (TF), proximal femoral (PF), distal femoral (DF), or proximal tibial (PT) megaprosthesis. TYPE: Systematic review.

LITERATURE SURVEY

Five research databases were searched systematically for original studies published in English from 2006 to 2017 that reported fitness, functioning, or exercise training responses for one or more of the four types of lower limb megaprosthesis listed above.

METHODOLOGY

Methodologic quality was assessed using a 22-item modified STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist.

SYNTHESIS

Of the 5342 articles retrieved, 28 met the inclusion criteria. Thirteen studies reported fitness outcomes, primarily in PT, with none in TF. Impaired knee extensor strength of the affected limb was reported following limb salvage with PF, DF, and PT megaprosthetics. Impaired flexibility was reported following limb salvage with DF and PT megaprosthetics. Functional outcomes were described in all studies and were most commonly reported using the Musculoskeletal Tumor Society (MSTS) system score. Results indicated no clear difference in functional outcomes between megaprosthesis locations. No studies evaluated exercise training responses.

CONCLUSIONS

This review identified impairments of lower limb strength and flexibility following limb salvage with a lower limb megaprosthesis. Similarity in functional outcomes for all four reported megaprosthetic locations may indicate a lack of sensitivity in outcome measures, including the absence of items assessing higher-level functioning. Exercise interventions that aim to improve fitness and function in this population have not been evaluated but are required given increasing 5-year survival rates.

LEVEL OF EVIDENCE

I.

Does Patellar Tendon Repair With Gastrocnemius Flap Augmentation Effectively Restore Active Extension After Proximal Tibial Sarcoma Resection?

BACKGROUND

A rotational gastrocnemius flap is often used for soft tissue reconstruction after proximal tibia sarcoma resection. However, little is known about the frequency and severity of complications and the recovery of extensor function after this procedure.

QUESTIONS/PURPOSES

After gastrocnemius flap reconstruction with split-thickness skin grafting (STSG) to augment the extensor mechanism repair after proximal tibial resection for sarcoma, we asked: (1) What ROM was achieved (including extensor lag and active flexion)? (2) How often did complications and reoperations occur and what caused them?

METHODS

Between 1991 and 2014, one surgeon treated 26 patients with proximal tibial resections for primary bone sarcoma. Of these, 18 were reconstructed with the preferred approach: resecting the proximal tibia leaving the patellar tendon in continuity with the tibialis anterior fascia whenever possible (10), cementing a stemmed proximal tibial endoprosthesis, suturing the patellar tendon to the implant, rotating a medial (16) or lateral (two) gastrocnemius flap over the tendon and prosthesis to augment the repair, and covering the flap with STSG. Alternative methods were used when this was technically impossible (one patient), when there was no advantage to secondary soft tissue coverage (two patients), or when the limb could not be salvaged (five patients). Of the 18 treated with gastrocnemius flaps, two were lost to followup or died of disease before the 24-month minimum and excluded; the median followup of the remaining 16 was 6 years (mean, 9.9 years; range, 2.3-21.7 years); three patients died of disease, and four have not been seen within the last 5 years. We reviewed medical records for passive and active extension, maximum flexion achieved, and complications requiring reoperation. ROM in patients with successful limb salvage was graded as excellent (flexion ≥ 110° and no lag), good (flexion 90°-110° and lag ≤ 10°), fair (one function limited: either flexion < 90° or lag > 10°), or poor (both functions limited: flexion < 90° and lag > 10°).

RESULTS

At latest followup, three patients had undergone amputation for deep infection. Of those remaining, median active flexion was 110° (mean, 104°; range, 60°-120°) and extensor lag was 0° (mean, 4°; range, 0°-10°). ROM was excellent in nine patients, good in three, fair in one, and poor in none. We observed 18 complications requiring reoperation in 12 patients, including deep infection (four), patellar tendon avulsion/attenuation (three), and flap necrosis (one). Survivorship free from revision or loss of the gastrocnemius flap was 74% (95% confidence interval [CI], 5.6-95.8) at 2, 5, and 10 years. Survivorship free from reoperation for any cause was 74% (95% CI, 52.0-96.0) at 2 years, 52% (95% CI, 25.8-77.8) at 5 years, and 35% (95% CI, 0-61.5) at 10 years using Kaplan-Meier analysis.

CONCLUSIONS

Although most patients regained functional ROM including active extension, 12 required reoperation for complications including infection and early extensor mechanism failures. Despite the observed risks, we believe the gastrocnemius flap with STSG should be considered a suitable approach to provide active extension and soft tissue coverage given the paucity of good surgical options for extensor mechanism reconstruction in this challenging clinical setting.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Large Osteochondral Allografts of the Knee: Surgical Technique and Indications

Large osteochondral allograft (OCA) transplant has become a valid alternative to restore articular surface in challenging articular lesions in young and active patients, either in primary or in revision procedures. Several studies support the effectiveness and safety of OCA, but costs and graft availability limit their use. The indications are the treatment of symptomatic full-thickness cartilage lesions greater than 3 cm ² , deep lesions with subchondral damage, or revision procedures when a previous treatment has failed. The goal of the transplant is to restore the articular surface with a biological implant, allow return to daily/sports activities, relieve symptoms, and delay knee arthroplasty. Grafts can be fresh, fresh-frozen, or cryopreserved; these different storage procedures significantly affect cell viability, immunogenicity, and duration of the storage. Dowel and shell technique are the two most commonly used procedures for OCA transplantation. While most cartilage lesions can be treated with the dowel technique, large and/or geometrically irregular lesions should be treated with the shell technique. OCA transplantation for the knee has demonstrated reliable mid- to long-term results in terms of graft survival and patient satisfaction. Best results are reported: in unipolar lesions, in patients younger than 30 years, in traumatic lesions and when the treatment is performed within 12 months from the onset of symptoms.

Knee function after limb salvage surgery for malignant bone tumor: comparison of megaprosthesis and distal femur allograft with epiphysis sparing

PURPOSE

Limb salvage surgery is increasingly used for the treatment of distal femur bone sarcomas. Total knee replacement using megaprosthesis and epiphysis-sparing biologic reconstruction using an allograft are widely used in order to preserve joint motion. We aimed to compare the results of these procedures using gait analysis in patients undergoing limb salvage surgery.

METHODS

Fifteen patients were included, nine undergoing allograft with epiphysis sparing (Allograft group) and six undergoing megaprosthesis (Megaprosthesis group). Every patient underwent a gait analysis using the Plug-in-Gait protocol. Spatiotemporal parameters, knee kinematics, and kinetics were compared between the two groups and a cohort of ten asymptomatic subjects. Knee function was assessed by the Gait Deviation Index (GDI) and the Gilette Gait Index (GGI).

RESULTS

Both treatment groups showed decreased knee flexion during the loading response phase. Megaprosthesis patients showed a decreased knee flexion all along stance phase. There was no difference in gait pattern between the treatment groups. GDI was significantly lower in Megaprosthesis and Allograft patients when compared to controls (86.4 and 84.3 vs 94, all p < 0.05). This difference was not clinically relevant.

CONCLUSION

Our study reveals that Megaprosthesis and Allograft patients did not show differences in gait patterns and global function. Even though Allograft and Megaprosthesis patients have significant changes in gait pattern, knee function is acceptable with effective gait mechanisms. Changes occur during stance phase and are due to the quadriceps weakness. The particular pattern of gait in Megaprosthesis patients could be a concern for prosthesis wear and should be investigated on this specific aspect.

LEVEL OF EVIDENCE

4.

Predictors of soft-tissue complications and deep infection in allograft reconstruction of the proximal tibia

BACKGROUND AND OBJECTIVES

Reconstruction of the proximal tibia after wide resection of malignant tumors in the pediatric population is very challenging. Advocates of allograft reconstruction argue as advantages bone preservation, biological reconstruction that facilitates reattachment of the extensor mechanism and other soft-tissue structures, delay of metallic prosthesis use and preservation of the distal femoral growth plate. However, complications are significant, infection being very common.

METHODS

Under IRB-approved protocol, 32 patients (17 males, 15 females), 13 years old in average (2-20), who underwent 33 allograft reconstructions of the proximal tibia, were evaluated for the occurrence of soft-tissue complications and/or deep infection (infection affecting the allograft). Potential predictors of soft-tissue complications and deep infection, categorized as pre- and perioperative variables, were analyzed in relation to the risk for developing a soft-tissue complication or a deep infection.

RESULTS

The prevalence of soft-tissue complications was 48% (16/33). However, we were not able to identify any significant predictors. The prevalence of deep (allograft) infection was 15% (5/33). Multivariate logistic regression determined higher BMI at the index surgical procedure and lower pre-operative WBC to be independent predictors of deep infection. For each unit of increase in BMI, the odds of deep infection increased by 40% (OR = 1.40; CI = 1.07-3.06; P < 0.05). For each one unit (1,000) of increase in the pre-operative white cell-count, the odds of deep infection decreased by 70% (OR = 0.30; 95%CI = 0.01-0.89; P < 0.05). Four of the five deep infections were in patients with soft-tissue complications, mainly wound dehiscence. However, wound dehiscence or soft-tissue complications were not predictive of deep infection.

CONCLUSION

Soft-tissue complications are prevalent in allograft reconstruction of the proximal tibia. Prevention is important as these may progress to deep infection. Careful attention to nutritional (BMI) and immunological status may help in patient selection for allograft reconstruction. If allograft reconstruction is opted for, efforts should focus on optimization of these factors as they proved to be independent predictors of subsequent deep infection. J. Surg. Oncol. 2016;113:811-817. © 2016 Wiley Periodicals, Inc.

lower limbs kinematic assessment of the effect of a gym and hydrotherapy rehabilitation protocol after knee megaprosthesis: a case report

[Purpose] To quantitatively assess the effect of a personalized rehabilitation protocol after knee megaprosthesis. [Subject and Methods] The gait patterns of a 33-year-old male patient with knee synovial sarcoma were assessed by a computerized analysis before and after 40 rehabilitation sessions. [Results] The rehabilitation protocol improved the gait pattern. After rehabilitation, hip flexion was nearly symmetric, with normalized affected limb hip flexion, and improved ankle flexion. Ankle in/eversion was asymmetric and did not improve after physiotherapy. Before physiotherapy, the hip flexion on the affected side anticipated the movement but nearly normalized in the follow-up assessment. Hip abduction range of motion increased, with wider movements and good balance. Knee range of motion nearly symmetrized, but maintained an anticipated behavior, without shock absorption at heel-strike. [Conclusion] Instrumental gait analysis allowed us to gain evidence about the training and how to expand rehabilitative interventions to improve efficacy. In particular, we recommend quadriceps and gastrocnemius eccentric contraction training (to improve the shock absorption phase, preventing early failures of the prosthesis); one-leg standing performance (to improve the support phase of the affected limb); adductor strength training (to aid in hip control during the swing phase); and peroneus strength training (to increase ankle joint stabilization).

Knee salvage procedures: The indications, techniques and outcomes of large osteochondral allografts

The overall incidence of osteochondral defect in the general population is estimated to be 15 to 30 per 100000 people. These lesions can become symptomatic causing pain, swelling and decreased function of the knee, and may eventually progress to osteoarthritis. In the young and active population, partial or total knee arthroplasty (TKA) is rarely the treatment of choice due to risk of early failure. Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients. The treatment reduces pain, improves function and is a viable limb salvage procedure for patients, especially young and active patients for whom TKA is not recommended. Either large dowels generated with commercially available equipment or free hand shell allografts can be implanted in more posterior lesions. Current recommendations for fresh allografts stored at 4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability, following screening and testing protocols. Higher rates of successful allograft transplantation are observed in younger patients, unipolar lesions, normal or corrected malalignment, and defects that are treated within 12 mo of symptom onset. Patients with bipolar lesions, uncorrectable malalignment, advanced osteoarthritis, and those over 40 tend to have less favourable outcomes.

Chondroblastoma of the knee treated with resection and osteochondral allograft reconstruction

Case. This case report describes the operative management of 16-year-old male with a symptomatic chondroblastoma of the distal femur with breach of the chondral surface. Following appropriate imaging and core needle biopsy, the diagnosis was confirmed histologically. The patient then underwent intralesional curettage and osteochondral allograft reconstruction of the defect. At one-year follow-up the patient was pain-free and has obtained excellent range of motion. There is radiographic evidence of allograft incorporation and no evidence of local recurrence. Conclusion. Osteochondral allograft reconstruction is an effective option following marginal resection and curettage of chondroblastoma involving the chondral surface of the distal femur.

The use of osteochondral allograft with bone marrow-derived mesenchymal cells and hinge joint distraction in the treatment of post-collapse stage of osteonecrosis of the femoral head

Osteonecrosis of the femoral head is an entity which occurs mainly in young and active patients aged between 20 and 50. The success of hip joint preserving treatments ranges from 15% to 50% depending on the stage and amount of osteonecrotic lesion. Total hip replacement is indicated in late post-collapse hips but it has unsatisfactory survival because of the wear and osteolysis in young and active patients. Osteochondral allografts have been reported in the treatment of large articular lesions with defects in underlying bone in knee, talus and shoulder. By combining osteoconductive properties of osteochondral allograft with osteogenic abilities of bone marrow-derived mesenchymal cells it has a potential to be an alternative to an autologous graft. The adjunct of hinged joint distraction should minimize stresses in subchondral bone to promote creeping substitution and prevent femoral head collapse. Unlike current treatment modalities, it would provide both structural support and allow bony and articular substitution.

Compensation by nonoperated joints in the lower limbs during walking after endoprosthetic knee replacement following bone tumor resection

BACKGROUND

Endoprosthetic knee replacement is often used to preserve joint function in patients with bone tumors of the distal femur or proximal tibia. Recently, because of improved oncologic outcome, surgeons are focusing more on the functional outcome of patients with musculoskeletal tumors. We hypothesized that patients who have undergone endoprosthetic knee replacement are forced to compensate for deficiency in their operated joint during walking. In this study, we investigated differences in gait kinematics, kinetics, and energetics between patients with endoprosthetic knee replacement and healthy subjects.

METHODS

We performed gait analysis for 8 patients who underwent endoprosthetic knee replacement after bone tumor resection and 8 matched healthy subjects. Gait kinematics, kinetics, and energetics of patients' ipsilateral and contralateral limbs were compared with those of healthy subjects by using Dunnett's test.

FINDINGS

Compared with healthy subjects, patients showed increased negative joint power around the ipsilateral ankle, greater second peak in the contralateral vertical ground reaction forces, and abnormal hip movement on both sides after initial contact.

INTERPRETATION

Patients tended to compensate for dysfunction of the reconstructed knee by muscles around the ipsilateral ankle and contralateral hip, with increased load on the contralateral limb during walking. These differences could lead to secondary impairments. Further analysis, including musculoskeletal simulation and assessment of long-term functional outcome with regard to secondary musculoskeletal impairment, is needed to verify the significance of the change in gait and to determine the need for special care for secondary musculoskeletal dysfunction in these patients.

Extensor function after medial gastrocnemius flap reconstruction of the proximal tibia

BACKGROUND

Reconstruction of the extensor mechanism after resection of the proximal tibia is challenging, and several methods are available. A medial gastrocnemius flap commonly is used, although it may be associated with an extensor lag. This problem also is encountered, although perhaps to a lesser extent, with other techniques for reconstruction of the extensor apparatus. It is not known how such lag develops with time and how it correlates with functional outcome.

QUESTIONS/PURPOSES

We therefore (1) assessed patellar height with time, (2) correlated patellar height with function using the Musculoskeletal Tumor Society (MSTS) score, and (3) correlated patellar height with range of motion (ROM) after medial gastrocnemius flap reconstruction.

METHODS

Sixteen patients underwent tumor endoprosthesis implantation and extensor apparatus reconstruction between 1997 and 2009 using a medial gastrocnemius flap after sarcoma resection of the proximal tibia. These patients represented 100% of the population for whom we performed extensor mechanism reconstructions during that time. The minimum followup was 2 years (mean, 5 years; range, 2-11 years). Fourteen patients were alive at the time of this study. We used the Blackburne-Peel Index to follow patellar height radiographically with time. Functional outcomes were assessed retrospectively using the MSTS, and ROM was evaluated through active extensor lag and flexion.

RESULTS

Eleven patients had patella alta develop, whereby the maximal patellar height was reached after a mean of 2 years and then stabilized. More normal patellar height was associated with better functional scores, a smaller extensor lag, but less flexion; the mean extensor lag (and flexion) of patients with patella alta was 17° (and 94°) compared with only 4° (and 77°) without.

CONCLUSIONS

In our patients patella alta evolved during the first 2 postoperative years. Patella alta is associated with extensor lag, greater flexion, and worse MSTS scores. Surgical fixation of the patellar tendon more distally to its anatomic position or strict postoperative bracing may be advisable.

LEVEL OF EVIDENCE

Level IV, clinical cohort study. See the Guidelines for Authors for a complete description of levels of evidence.

Patterns of improvement following oncologic reconstructrion compared to total knee arthroplasty and revision knee arthroplasty

Limb salvage surgery for primary malignant bone tumors of the lower limbs requires complete resection of the tumor, followed by a reconstruction to restore function. In contrast to the abundant information on total knee arthroplasty, data on the recovery pattern of limb salvage surgery is largely limited. With the aim of guiding patient expectations and optimizing care, we retrospectively compared the clinical outcomes among patients following oncologic knee reconstruction, primary total knee arthroplasty, and revision total knee arthroplasty. From January, 2001 to June, 2009, we identified a cohort of 503 primary total knee arthroplasties, 55 revision knee arthroplasties, and 15 oncologic reconstructions. Outcomes were assessed by the validated Short Form-36 (SF-36) health questionnaire. We found that oncologic patients significantly improved their Physical Component Score at one and minimum two-year follow up compared to baseline (p< 0.05) with the majority of improvement (90%) made within the first year following surgery. This is a similar pattern to that observed following primary and revision total knee arthroplasty.

Cemented endoprosthetic reconstruction of the proximal tibia: how long do they last?

BACKGROUND

The few available studies documenting the long-term survival of cemented proximal tibial endoprostheses for musculoskeletal tumors do not differentiate between stem designs or patient diagnosis. There is wide variation in survival rates reported, possibly a result of this heterogeneity in patient population and implant design.

QUESTIONS/PURPOSES

We therefore asked: (1) How long do proximal tibial endoprostheses last? (2) What is the typical long-term functional result after proximal tibial replacement? And (3) what are the short- and long-term complications associated with endoprosthetic reconstruction of the proximal tibia, particularly with respect to the soft tissue reconstruction?

PATIENTS AND METHODS

We retrospectively reviewed 52 patients with 52 proximal tibial endoprosthetic reconstructions for a tumor-related diagnosis. Kaplan-Meier survivorship analysis was performed using revision of the stemmed components for any reason as an endpoint for implants, and death due to disease progression for patients. Function was assessed using the MSTS scoring system. The minimum followup was 1 month (mean, 96 months: range, 1-284 months; median, 69 months).

RESULTS

Using revision of the stemmed components for any reason as an end point, overall prosthesis survival at 5, 10, 15, and 20 years was 94%, 86%, 66%, and 37%, respectively. The 29 modular implants demonstrated a trend toward improved survival compared to the 23 custom-designed components, with a 15-year survivorship of 88% versus 63%. The mean postoperative Musculoskeletal Tumor Society score at most recent followup was 82% of normal function (mean raw score, 24.6; range, 4-29).

CONCLUSIONS

Cemented endoprosthetic reconstruction of the proximal tibia provides a reliable method of reconstruction following tumor resection.

Bone tumors: osteosarcoma and Ewing's sarcoma

PURPOSE OF REVIEW

Osteosarcoma and Ewing's sarcoma are the two most common primary malignant bone tumors in children and account for approximately 6% of all childhood malignancies. Treatment methods have seen significant advancements, particularly in regard to chemotherapy and limb-sparing surgery. These advancements have led to increased survival rate. With many long-term survivors, it is important to evaluate long-term patient outcomes following treatment, including function and health-related quality of life. We will review the current trends in treatment of these diseases, different reconstructive options available, and the methods and results for evaluating the long-term results.

RECENT FINDINGS

There have been many improvements in the medical treatment of these tumors leading to increasing long-term survival. There have also been improvements in reconstructive techniques for the maintenance of functional extremities in these patients. Newer evaluation methods for both functional outcome and health-related quality of life measures that are more specific to children and adolescents are being developed and in use.

SUMMARY

This report will provide an overview of the current treatment options and long-term complications in primary malignant bone tumors for the pediatrician caring for a child with these problems.