An electrosurgical apparatus for ligament tightening, the apparatus comprising: an electrosurgical generator arranged to generate and output microwave electromagnetic energy; a probe connected to the electrosurgical generator, the probe comprising: a flexible shaft containing a coaxial transmission line for conveying the microwave EM energy; and an applicator at a distal end of the flexible shaft, the applicator having an energy delivery structure arranged to receive the microwave EM from the coaxial transmission line and emit the received microwave EM energy into a treatment zone adjacent to the applicator; a detector arranged to monitor a property of the treatment zone; and a controller arranged to control an energy delivery profile of the microwave EM energy delivered to the probe based on information obtained by the detector, wherein the energy delivery profile is either: (i) a measurement energy delivery profile, or (ii) a therapeutic energy delivery profile, wherein a power magnitude of the therapeutic energy delivery profile is larger than a power magnitude of the measurement energy delivery profile; wherein the detector comprises a power sensing module arranged to detect a forward power signal of the measurement energy delivery profile travelling from the electrosurgical generator to the probe and a reflected power signal reflected back from the probe, wherein the controller is arranged to process the detected forward and reflected power signals to obtain information indicative of a type of body tissue in the treatment zone, and wherein the controller includes a memory storing reference data and a microprocessor arranged to: execute software commands to compare the information indicative of type of body tissue in the treatment zone with the reference data, and detect the presence of nerve tissue in the treatment zone from the comparison; and select the therapeutic energy delivery profile when it is determined that nerve tissue is absent from the treatment zone. an electrosurgical generator arranged to generate and output microwave electromagnetic energy; a probe connected to the electrosurgical generator, the probe comprising: a flexible shaft containing a coaxial transmission line for conveying the microwave EM energy; and an applicator at a distal end of the flexible shaft, the applicator having an energy delivery structure arranged to receive the microwave EM from the coaxial transmission line and emit the received microwave EM energy into a treatment zone adjacent to the applicator; a flexible shaft containing a coaxial transmission line for conveying the microwave EM energy; and an applicator at a distal end of the flexible shaft, the applicator having an energy delivery structure arranged to receive the microwave EM from the coaxial transmission line and emit the received microwave EM energy into a treatment zone adjacent to the applicator; a detector arranged to monitor a property of the treatment zone; and a controller arranged to control an energy delivery profile of the microwave EM energy delivered to the probe based on information obtained by the detector, wherein the energy delivery profile is either: (i) a measurement energy delivery profile, or (ii) a therapeutic energy delivery profile, (i) a measurement energy delivery profile, or (ii) a therapeutic energy delivery profile, wherein a power magnitude of the therapeutic energy delivery profile is larger than a power magnitude of the measurement energy delivery profile; wherein the detector comprises a power sensing module arranged to detect a forward power signal of the measurement energy delivery profile travelling from the electrosurgical generator to the probe and a reflected power signal reflected back from the probe, wherein the controller is arranged to process the detected forward and reflected power signals to obtain information indicative of a type of body tissue in the treatment zone, and wherein the controller includes a memory storing reference data and a microprocessor arranged to: execute software commands to compare the information indicative of type of body tissue in the treatment zone with the reference data, and detect the presence of nerve tissue in the treatment zone from the comparison; and select the therapeutic energy delivery profile when it is determined that nerve tissue is absent from the treatment zone. execute software commands to compare the information indicative of type of body tissue in the treatment zone with the reference data, and detect the presence of nerve tissue in the treatment zone from the comparison; and select the therapeutic energy delivery profile when it is determined that nerve tissue is absent from the treatment zone.