Page 52 - Read Online

Page 10 of 14 Pinnamaneni et al. J Cancer Metastasis Treat 2021;7:7 I http://dx.doi.org/10.20517/2394-4722.2020.94

may be difficult to locate depending on access to tissue banks and available stock. The treatment of these
potential complications is case dependent.

[13]
Outcomes: A 1990 series of 16 patients from Massachusetts General reported 68% survivorship at 5 years .
[13]
Mean MSTS score decreased from 81% at 14 months to 70% at 34 months . In a 2015 series of 19 patients
from the Buenos Aires, graft survival rate was 55% at 10 years with mean MSTS score of 76% in patients
[9]
with retained allografts .
Endoprosthesis
Reconstruction of the proximal humerus may also be done with an endoprosthesis construct using readily
available modular implants [Figures 3 and 4]. Their modularity allows for restoration of humeral height,
soft-tissue tensioning, and amount of constraint but does not provide the potential for soft-tissue healing to
the reconstruction.

Indications: Endoprosthesis reconstructions should be considered in patients who have intra-articular
tumor involvement and those with limited expected survival who need immediate stability and early
functionality. Most endoprosthesis implants are usually implanted as hemiarthroplasties [Figures 3 and 4],
but some modern endoprosthesis implants have the convertibility to be placed in a reverse total shoulder
arthroplasty (RTSA) configuration and accommodate a glenosphere.

Technique: As for any planned proximal humeral resection/reconstruction, the planned length of resection
should be measured on preoperative advanced imaging, and preservation of soft tissues that can be
repaired during the reconstruction should be accomplished during the resection. The deltoid insertion
should be spared if possible. The glenohumeral capsule and the respective tendon stumps should be tagged
with sutures for later identification. These structures are useful in achieving joint stability by attaching
these soft-tissue attachments to the endoprosthesis. After measuring the resected specimen, the defect
is reconstructed by combining the modular humeral head, body, and shaft endoprosthetic components
to achieve optimal soft-tissue tensioning. If adequate distal fixation is not achieved with uncemented
intramedullary stem, cemented techniques should be used.

Soft-tissue repair to endoprosthesis can utilize attachment of soft tissue proximally to holes in the
endoprosthesis with non-absorbable sutures. Soft-tissue repair can be augmented by an aortic synthetic
[14]
mesh graft placed over the endoprosthesis to which the soft tissues can be sutured .

In RTSA endoprostheses, adequate lateralization and standard glenosphere placement techniques should
be used. Since endoprosthetic reconstruction after oncologic resection has a higher instability risk
compared to non-oncology patients, when using a RTSA, techniques to increase stability include increased
lateralization of the glenosphere, a larger glenosphere, and a constrained humeral insert.

Postoperatively, the patient is placed in a sling. Initially, the patient is non-weightbearing and range of
motion to the shoulder is limited. Often with endoprosthesis reconstruction, immediate light weightbearing
and active assisted range of motion exercises can be initiated.

Advantages [Table 5]: The advantages of endoprosthesis reconstruction are modularity, early return to
function, lower reported complication rates, and superior implant survival [15-17] . This reconstruction option
also eliminates allograft specific concerns including allograft-host integration, subchondral collapse,
allograft fractures, and non-union.