Ubuntu16.04でsudo apt-get upgradeができない

sudo apt-get upgradeを実行すると以下のエラーをはきます。

$ sudo apt-get upgrade 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  apt apt-utils dpkg libapt-pkg5.0 libvtk6-dev libvtk6-java libvtk6-qt-dev
  libvtk6.2 libvtk6.2-qt python-vtk6 tcl-vtk6 ubuntu-advantage-tools
  update-notifier update-notifier-common vtk6
The following packages will be upgraded:
  apt-transport-https base-files dpkg-dev grub-common grub-efi-amd64
  grub-efi-amd64-bin grub-efi-amd64-signed grub2-common initramfs-tools
  initramfs-tools-bin initramfs-tools-core libapt-inst2.0 libdpkg-perl
  libgnutls-openssl27 libgnutls30 libpam-modules libpam-modules-bin
  libpam-runtime libpam-systemd libpam0g libpcl-apps1.7 libpcl-common1.7
  libpcl-dev libpcl-features1.7 libpcl-filters1.7 libpcl-io1.7
  libpcl-kdtree1.7 libpcl-keypoints1.7 libpcl-octree1.7 libpcl-outofcore1.7
  libpcl-people1.7 libpcl-recognition1.7 libpcl-registration1.7
  libpcl-sample-consensus1.7 libpcl-search1.7 libpcl-segmentation1.7
  libpcl-surface1.7 libpcl-tracking1.7 libpcl-visualization1.7 libpcl1.7
  libpq-dev libpq5 libprocps4 libseccomp2 libsystemd0 libudev-dev libudev1
  openssh-client openssh-server openssh-sftp-server procps python-apt-common
  python-sip python-sip-dev python-tornado python3-apt python3-distupgrade
  shim shim-signed sip-dev ssh systemd systemd-sysv ubuntu-desktop
  ubuntu-keyring ubuntu-minimal ubuntu-release-upgrader-core
  ubuntu-release-upgrader-gtk ubuntu-standard udev unattended-upgrades
71 upgraded, 0 newly installed, 0 to remove and 15 not upgraded.
Need to get 0 B/24.1 MB of archives.
After this operation, 3,551 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Extracting templates from packages: 100%
Preconfiguring packages ...
dpkg: error: error removing old backup file '/var/lib/dpkg/status-old': Is a directory
E: Sub-process /usr/bin/dpkg returned an error code (2)

一番下のエラーにある
・dpkg: error: error removing old backup file '/var/lib/dpkg/status-old': Is a directory
・E: Sub-process /usr/bin/dpkg returned an error code (2)

について調べると、私のPCの/var/lib/dpkg内には本来あるはず？のstatus-oldファイルがないことが分かりました。satusとstatus-newがあります。
このファイルがないことが原因かもしれないのですが、解決策はございますでしょうか？
まだ別の問題の可能性もありますか？